Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：HARBIN INSTITUTE TECHNOLOGY PUBLISHERS  

Multiple-way power divider/combiner's with a rectangular waveguide port for input/output signal and microstrip line ports for output/input signals are presented. A number of dividing/combining units are successively connected in the chain structure. The unit is composed of the rectangular waveguide section with the microstrip-line probe pair and the thin narrow section. Using as the divider, the chain structure has wideband performance due to the traveling-wave opeartion. High isolation between the paired ports in the unit is established by connecting the paired microstrip lines via a chip resistor. The four-way divider/combiner operating at X-band is designed. The broadband characteristics and. high isolations among the furcated ports are confirmed by the prototype divider/combiner.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SCRIPTA TECHNICA-JOHN WILEY & SONS  

The system configuration, fundamental operation, and PSK modulation of the output wave are discussed for the phased array operation of a mutually coupled one-dimensional oscillator array when signals with different phases are injected at the two ends to make use of the mutual locking and injection locking phenomena. First, the equivalent circuit is analyzed and the condition of phased array operation is derived. It is shown that both the desired mode, appropriate for the phased array operation, and other modes exist. It is demonstrated that injecting the injection signal at the center of the array is effective in enhancing the stability of the desired mode. The transient response of the array is analyzed when a PSK signal is used as the injection signal. A possible means of obtaining a PSK modulated wave as the output is presented. An experiment in the X band, using waveguide oscillators and an active patch antenna array is described. The results are close to the theoretical predictions. (C) 1997 Scripta Technica, Inc.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：CITY UNIVERSITY HONG KONG  

Full wave FD-TD analysis has been carried out for coaxial probe inserted into a waveguide so as to achieve coaxial-waveguide transition. Including cases for probes with large diameter and extension length, equivalent admittances agreed well with corresponding measured results and have been provided as useful data for circuit design. Field concentration which ought to be taken into account for high power application design has been also discussed by field distribution.

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Other Link： http://orcid.org/0000-0003-2642-5296

Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：CITY UNIVERSITY HONG KONG  

We investigate an axially symmetrical Fabry-Perot oscillator with active devices inserted in a dielectric substrate for power combining of many more devices in microwave and millimeter wave frequency range. Empirically in this oscillator, efficient power combining can be done when it oscillates approximately at the frequency which corresponds to the wavelength equal to twice the spacing between devices. The wavelength in tile dielectric is shorter than in free space, so we tried to insert tile devices in the dielectric substrate in order to increase the number of the devices. By measuring the oscillation frequency of the oscillator with sixteen devices at X-band, we confirmed that the spacing between devices was about a half wavelength in the dielectric. We achieved almost perfect power combining of sixteen devices.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：CITY UNIVERSITY HONG KONG  

In order to realize useful active phased array antennas, we have investigated the phased array behavior of a microwave coupled oscillator system which has locking sources at both ends and is controlled by the phases of the injection signals. By numerical analysis, we show that free-running frequency shift of the end oscillator of the array is effective for enlarging the scanning range of the radiated beam. An experiment on a system of waveguide type oscillators has confirmed the analytical result and rye have successfully scanned the wave radiated from an array with five active patch antennas mounted with Gunn diodes.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：I E E E  

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Measurements of scattering parameters of devices with rectangular waveguide ports and coaxial line ports have been investigated. Unknown "thru" calibration was employed for characterizing a transition for converting the coaxial line test port to the waveguide. Transmission phase of the unknown "thru" must be known to within ±90° in the calibration procedure. A transition from the coaxial line to the waveguide used as the unknown "thru" was designed with an electromagnetic field simulator, and simulated values of the transmission phase was adopted as the required known values. The scattering parameters of a waveguide section with a coaxial probe were measured with a fabricated unknown "thru."

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Language：English   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

A rectifying antenna is one of the most important components for wireless power transmission applications. In our previous papers, some RF-DC conversion circuits with high conversion efficiency at low input power are proposed. However, these RF-DC conversion circuits have some parts of which size depends on operating frequency, so the circuit size becomes large at low operating frequency. And, the composition of these RF-DC conversion circuits is complicated. Therefore, in this paper, a new RF-DC conversion circuit composed of only chip devices is proposed. This circuit has higher conversion efficiency than the previously proposed circuits. And, size reduction of the RF-DC conversion circuit is realized. Moreover, the composition of the circuit is simple, so the circuit size does not depend on operating frequency. For design of the RF-DC conversion circuits, LE-FDTD method is used. The measurement results agree with analytical results of the LE-FDTD method very well, and availability of the LE-FDTD method is discovered. It is shown that LE-FDTD method is a powerful analytical way which can give efficient design of RF-DC conversion circuit with high conversion efficiency.

DOI： 10.1587/transele.E93.C.1323

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Loss reduction of a power divider mechanical-controlling dividing ratio has been investigated. The divider consists of a rectangular waveguide section with a coaxial probe in order to deliver microwave power from the waveguide to the coaxial line, and three rotary fins and one metal rod are incorporated for mechanical-control of the dividing ratio. High power experiments and electromagnetic field simulations revealed to be that the cause of high insertion loss of the divider is the conductor loss by large current flowing on surfaces of the fin edges and the H plane waveguide walls facing each other. The rotary fins with the shape of character "H" are employed for reduction of the large current. It was confirmed that the power insertion loss ratio of the prototype divider is less than 6.5%.

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For designing a high-efficiency RF DC conversion circuit, simulations and trial and error usually occupy a large part of the work. Such design method needs much time. The important part of design is to design an input circuit. The efficiency of a conversion circuit mainly depends on input circuit. However, it is difficult to design the input circuits. This study takes notice of the voltage when the DC load resistance is open. The open DC load voltage is an important quantity for design of the high-efficiency RF DC conversion circuit. We show by experiments and simulations that the efficiency of an RF DC conversion circuit tends to increase with the open DC load voltage. This relation can make it easier to design RF DC conversion circuit.

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A power divider mechanical-controlling dividing ratio for the microwave power distribution system in buildings has been investigated. The divider consists of a rectangular waveguide section with a coaxial probe in order to deliver microwave power from the waveguide to the coaxial line, and three rotary fins and one metal rod are incorporated for mechanical-control of the dividing ratio. The divider with the range of the delivered power ratio to the coaxial line from 1.6% to 67.6% under less than -24.6dB return loss was designed by electromagnetic field simulations. By experiments of a prototype power divider based on the design, the capability of controlling the dividing ratio was confirmed.

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This paper proposes the compact size rectenna using the open ended diamond antenna which is radiation pattern of sharp. This antenna which is fabricated at the planer has same dimension as the patch antenna. In addition,this antenna's half beamwidth is more narrow than the patch antenna. To realize the compact size rectenna,the dimension of the rectification circuit is smaller than the antenna. So the rectification circuit is constructed of the chip device has the 59.5% of conversion efficiency and the dimension of this circuit has 10mm x 10mm at 5.8GHz. The rectenna array which is composed of 2 elements is fabricated, and confirm operating. As a result the output voltage is 117mV at 0.6m, and 69mV at 1.0m.

DOI： 10.1109/EUMC.2009.5295939

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One-dimensional CRLH transmission lines are aligned to construct two-dimensional medium with imaging capability not found in homogeneous materials. Mimicking electromagnetic field distribution on a surface of the perfect lens, high resolution imaging is demonstrated. Unlike transmission configurations such as in a lens, the imaging operation proposed in this paper is not disturbed by dissipation or index mismatch, leading to wide band operations.

DOI： 10.1109/EUMC.2009.5296485

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In recent years, the development of the in-vivo medical devices are remarkable. Generally, in-vivo devices need the internal battery. The life of internal battery is limited, and the maintenance of the battery is necessary.
For overcoming this problem, the ultrasonic wireless power transmission technology is studied. In the past reports, the transducer of ultrasonic wireless power transmission system is not designed for electrical matching with input source, amplifier circuit, and rectification circuit, etc.
In this paper, we propose the efficient ultrasonic wireless power transmission system. For realizing the efficient system, the impedance matching between the input source, amplifier circuit and the ultrasonic transducer is considered. And the optimum position of two transducers necessary for achieving a high transmission efficiency is searched. Moreover, the voltage booster circuit to obtain the high DC oputput voltage is designed. In the transmission experiment, it is confirmed that the high DC output voltage for the operation of the in-vivo devices is achieved.

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Recently, various wireless applications have hugely become popular. Especially, mobile terminals such as mobile phones are actively developed. In developments of mobile terminals, miniaturization and frequency multiband of antennas are very important issues. However, there are no rational design strategy in small antenna designs. So, antenna developments depends on electromagnetic simulators or capability of engineer. And many cut-and-try processes are necessary for achieving desired characteristic. This makes many problems such as prolongation of developments. Then, now, automatic design techniques of antenna using genetic algorithm (GA) are paid attention.
In this paper, the new design strategy for miniaturization of antennas is proposed by operation of chromosome-length in GA. Proposed design technique provides a minimum area necessary for keeping characteristics of a antenna. And, efficient miniaturization of a antenna and removing many undesirable conductors in a design ares are possible. Removing undesirable conductors provides lower-cost designing of antennas. The new design method can become rational design strategy for antennas miniaturization.

DOI： 10.1109/APMC.2009.5384162

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

Cylindrical power divider/combiner's with broadband coaxial-conical-radial line transition have been studied, which have broadband and low loss characteristics required for the power dividing-combining systems in order to realize microwave high power solid-state amplifiers. The power divider/combiner's is composed of the coaxial-conical-radial line transition as the central part, and the peripheral part in which the coaxial probes are line. In the transition, the coaxial line is converted via two sections of the conical lines to the radial line. The characteristic impedance of the radial line has an imaginary part, and so that the conical line of the second stage is used as a matching line such as the quarter-wavelength transformer. Therefore, the transition can be designed which have lower return loss in the wide frequency range. The validity of the design procedure was confirmed with the experiments for the prototype twelve-way dividers.

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Inverse class-C frequency doubling operation has been discussed for frequency doublers and second harmonic oscillators with high output power and high efficiency. It was demonstrated that high second harmonic output power can be obtained with high drain efficiency higher than 60% when the load whose impedance is infinity at all odd harmonicfrequencies including fundamental frequency and the same resistance at all even harmonic frequencies is used by inverse class-C operation. the drain efficiency higher than 80% can be achieved by the larger input power.

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A Rectifying Antenna (Rectenna) is one of the most important components for a wireless power transmission. It has been developed for many applications such as Space Solar Power System (SSPS), Radio Frequency IDentification (RF-ID), and electric vehicle etc. The Rectenna consisting of RF-DC conversion circuits and receiving antennas needs to be designed for high conversion efficiency to achieve efficient power transmission. In this paper, we investigated the RF-DC conversion circuits by the theoretical analysis. And, we propose the theoretical formula for calculating the output DC voltage in giving the input voltage. The result that is calculated by the formula agreed with the simulator's result, so, we confirmed the validity of the formula we derived. The theory and the formula we derived are useful in order to know the basic operation of the RF-DC conversion circuit, and to design the circuit efficiently.

DOI： 10.1109/EMICC.2008.4772306

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Transmission line metamaterials based on composite right-left handed (CRLH) structures with pseudoperiodicity are proposed and analyzed experimentally. These metamaterials can be used in various microwave circuits to control not only amplitude but also phase responses of electromagnetic waves. Introducing some kinds of pseudoperiodicity can control phase responses of reflected waves, without affecting severely on electromagnetic bandgap (EBG) properties of periodic structures. Equivalent circuit approaches including distributed line sections are used to design non-periodic structures, resulting in an efficient design procedure. Pseudoperiodic design is also useful for homogenization of conventional metamaterials.

DOI： 10.1109/EUMC.2008.4751685

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DOI： 10.1109/APMC.2008.4958300

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DOI： 10.1109/APMC.2008.4958657

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The trend of microwave circuits has been toward highly integrated systems. Most design tools for designing microwave circuits mounted the linear or the nonlinear devices adopt the fundamental circuit theory using the S matrix on the frequency domain. The harmonic balance method is also used to correspond to the nonlinear circuit. Therefore, the effect of the electromagnetic field, for example, a mutual coupling between sub-circuits through the, space is almost disregarded. To calculate these circuits included its surrounding electromagnetic field, the finite difference time domain method combined with the equivalent circuit simulation had been presented as the lumped element FDTD (LE-FDTD) method. In general, even if an analytical target is a linear circuit, the FDTD method requires very long analytical time. In this paper, we propose an efficient LE-FDTD method to reduce the analytical time. We investigate its efficiency to compare with the conventional LE-FDTD method or measurements, consequently, it is confirmed that the proposal method requires only at analytical time of 1/10 compared with the conventional method. We also show that the proposal method is able to analyze characteristics of the active integrated antenna (AIA) which are practicably impossible to analyze by using the conventional method.

DOI： 10.1093/ietele/e90-c.9.1776

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In the second harmonic generation with FETs, optimum configuration of input circuits connected to the gate terminal and output circuits connected to the drain terminal have been investigated. Circuit simulations and experiments of frequency doublers revealed that the input circuits which are conjugately matched with the gate terminal or the fundamental component and has an appropriate reactance at the second harmonic frequency, and the output circuit with the fundamental reactive termination for the inverse class-C operation are required for efficient frequency doubling. By applying the optimum input and output circuits to the single ended second harmonic oscillators, output powers of higher than 20mW and drain efficiencies of higher than 20% were obtained in both cases of the fundamental oscillation frequency of 4GHz and 6GHz.

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A Rectifying Antenna (Rectenna) is one of the most important components for a wireless power transmission. It has been developed for many applications such as Space Solar Power System (SSPS), and Radio Frequency Identification (RFID) etc. The Rectenna consisting of RF-DC conversion circuits and receiving antennas needs to be designed for high conversion efficiency to achieve efficient power transmission. In this paper, we try to design the mw-Class RF-DC conversion circuit using full-wave rectification.

DOI： 10.1109/EUMC.2007.4405340

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In order to obtain high output power in higher frequency range such as millimeter wave, an input gate network for second harmonic FET oscillators has been investigated. In the frequency doubler, by using the input network which matches the gate terminal to signal source impedance for fundamental component and has pure reactance at both second and third harmonic frequencies, considerably high output power of second harmonic component was obtained compared with the case using a simple 50Ω line as an input network. The same input network was implemented with the second harmonic oscillator with the fundamental oscillation frequency of 4GHz, and high output power of second harmonic was obtained as 26mW.

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The trend of microwave circuits has been toward highly integrated systems. Most design tools for circuits are based on the fundamental circuit theory using the S matrix combined with the harmonic-balance method. Consequently, the electromagnetic effect is ignored or approximated at best. Therefore, the extended finite-difference time-domain(FDTD) method combined with the equivalent circuit simulation had been presented. However, it takes very long times to analyze any circuits. In this paper, we propose a novel extended FDTD method to reduce calculation resources. We investigate its efficiency to compare with the conventional extended FDTD method or measurements, consequently, it is confirmed that the proposal method is required calculation resources less than 10% compared with the conventional method. We also show that the proposal method is able to analyze characteristics of the active integrated antenna(AIA) which are practicably impossible to analyze by using the conventional method. Copyright 2006 IEICE.

DOI： 10.1109/APMC.2006.4429570

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A Rectenna is one of the most important components for a wireless power transmission. It has been developed for many applications such as Space Solar Power System (SSPS), and RFID etc. The rectenna consisting of RF-DC conversion circuits and receiving antennas needs to be designed for high conversion efficiency to achieve efficient power transmission. In this paper, the extended FDTD method is proposed as a method for calculating the RF-DC conversion circuit, and the availability of this method is confirmed. Furthermore, the output power from the circuit including the radiation power is investigated. Copyright 2006 IEICE.

DOI： 10.1109/APMC.2006.4429790

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In order to realize more miniaturized wireless terminals with multi-function, an active integrated antenna which receives RF signal and down-converts it into IF signal has been investigated. The active antenna consists of a patch antenna and a feedback oscillator operating as a self-oscillating harmonic mixer where the IF is equal to difference between the RF and double of local oscillating (LO) frequency. Characteristics of a used FET were measured so that optimum LO input signal level to the gate and optimum feedback factor in local oscillation with maximum RF-IF conversion efficiency were obtained. By experiments of the self-oscillating mixer with the optimum feedback factor, the maximum conversion efficiency was obtained. In the active integrated antenna with the optimum mixer, high RF-IF conversion efficiency of -0.8dB was achieved.

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Active integrated antenna techniques have high potential for giving smaller size, lighter weight, lower cost and higher efficiency, in particular to millimeter-wave circuit-antenna systems. This paper gives a review of active integrated antenna techniques with emphasis on beam steering and retrodirective antenna arrays. Various beam steering operations of integrated antenna oscillator arrays using locking phenomena are presented. Beam steering arrays of such type have the feature that phase shifters are not necessary in the arrays. Arrays with higher harmonic output radiation can enlarge the beam steering range. Arrays of locked active antennas which operate as self-oscillating mixers can be beam controllable receiving antennas.

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Language：English   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

Active integrated antenna techniques have high potential for giving smaller size, lighter weight, lower cost and higher efficiency, in particular to millimeter-wave circuit-antenna systems. This paper gives a review of active integrated antenna techniques with emphasis on beam steering and retrodirective antenna arrays. Various beam steering operations of integrated antenna oscillator arrays using locking phenomena are presented. Beam steering arrays of such type have the feature that phase shifters are not necessary in the arrays. Arrays with higher harmonic output radiation can enlarge the beam steering range. Arrays of locked active antennas which operate as self-oscillating mixers can be beam controllable receiving antennas.

DOI： 10.1093/ietele/e88-c.7.1358

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Beam control using active antenna arrays with selfoscillating harmonic mixers has been investigated. The active antenna is composed of a patch antenna receiving RF signal and a parallel feedback type oscillator which operates as the self-oscillating harmonic mixer, and down-converts the received RF signal into IF signal. The mixer has two ports for local oscillating (LO) signal. One is an output port extracting the LO signal. The other is an input port for an injection signal to synchronize the local oscillation. The mixers can be coupled unilaterally without other nonreciprocal components by connecting the output port to the input port in the next mixer. In the unilaterally coupled array, the phase differences of the LO signals between the adjacent mixers can be varied without phase shifters in injection locking state by changing the local free-running frequencies of the self-oscillating mixers. The receiving pattern can be controlled by combining the IF signals from the individual active antennas, which have phases associated with the LO signals. The IF is difference between the RF and double of the LO frequency so that arbitrary phase differences from 0 to 2 pi radian can be provided to the output IF signals. The experiments using the two- and three-element arrays demonstrated beam control capability.

DOI： 10.1093/ietele/e88-c.7.1375

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In order to obtain high output power in higher frequency range such as millimeter wave, optimum fundamental load impedance for second harmonic oscillator has been investigated. First, fundamental load reactance of frequency doublers for maximum second harmonic output power was obtained by an approximated equivalent model for the used FET and experiments of the fabricated doublers. When the second harmonic oscillator with fundamental oscillation frequency of 6GHz had the fundamental load impedance whose the imaginary part was nearly equal to the value for the frequency doubler with the same FET, second harmonic output power and drain efficiency were obtained as 27mW and 26%, respectively.

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The rectangular waveguide chain power divider/combiner with microstrip line probe pairs has been presented. The divider/combiner is composed by connecting successively dividing/combining units each of which consists of microstrip line probes inserted into a rectangular waveguide and a thin narrow waveguide section and has broadband performance. High isolation between the paired branch ports in the unit can be obtained with coupling of the paired microstrip lines via a chip resistor. The experiments at X-band showed wideband dividing characteristics and high isolation among the furcated ports of the prototype four-way divider/combiner.

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For applications of the microwave power transmission technology, it is necessary to realize high efficiency rectennas or rectification circuits. Especially, RF-ID's or ubiquitous power sources demand high RF-DC conversion efficiency for below, mW microwave inputs. However, almost all past rectennas or rectification circuits were designed for over 100 mW rectifying and the RF-DC conversion efficiencies were less than 20% at 1mW microwave input. In this paper, we investigate rectification circuits for developing mW-class rectennas. Discussing diode mount structures in order to increase the efficiency below 10 mW microwave input, we succeeded in developing a rectification circuit whose efficiency is 62.8% for a 10 mW microwave input. We also find that approximately 30% of the input microwave power is consumed by the diode in the rectification circuit.

DOI： 10.1109/EUMC.2005.1610187

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In this paper, we analize rectification circuit for low power microwave rectenna mounting a shottky diode to use FDTD method, and investigate parameters to archive a high RF-DC conversion efficiency by the voltage waveform and the current distribution. In addition, we confirm the availability of this method by comparing the load voltage obtained by FDTD analysis with the measured result.

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In this paper, we argue about miniaturization of circularly polarized wave patch antenna with cross-shaped slits. By comparing result of analysis to result of experiment, we check the adequacy of FDTD method, and we set up some notches or some cross-shaped slits on the patch antenna to make it small, and we consider miniaturization of circularly polarized wave patch antenna quantitatively by FDTD method. As a result we show 60% miniaturization when we set up four 12mm notches and we show 50% miniaturization when we set up four 12mm cross-shaped slits. Furthermore patch antenna has a high order mode resonance when we set up some notches or cross-shaped slits. We show the factor of this resonance.

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Cylindrical power divider/combiner's with coaxial-conical-radial line transformation have been studied, which have broadband and low loss characteristics required for the power dividing-combining system in order to realize microwave high power solid-state amplifiers. The divider/combiner is composed of the central part in which has coaxial-conical-radial line transformation, and the peripheral part in which the coaxial probes are inserted into the radial line. Each part is designed with the electromagnetic simulator in order to have wide bandwidth. The divider/combiner's are constructed by connecting the optimum central and peripheral parts. In the experiment for the prototype twelve-way divider/combiner, the relative bandwidth, in which the return loss is less than -20dB, was achieved with 68.9%.

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A conical-radial wave power divider/combiner has been studied, which has broadband and low loss characteristics required for the power dividing-combining system in order to realize microwave high power solid-state amplifiers. In this paper, the optimum design with the electromagnetic simulator for the divider is presented. The divider is composed of the central part in which the input coaxial line is transformed into the conical line followed by the radial line, and the peripheral part in which the coaxial probes are inserted into the radial line. Each part is designed in order to have wide bandwidth. The divider is constructed by connecting the optimum central and peripheral parts. The designed twelve-way divider has the relative bandwidth of 44% in which the return loss is less than -20dB. In the experiment, the wider relative bandwidth was achieved with 47%.

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A phased array behavior of a unilaterally coupled active antennas has been investigated. The active antenna is composed of a patch antenna and a parallel feedback type oscillator which can be coupled unilaterally to other oscillators without other nonreciprocal components. Numerical calculations of the reduced equations describing the behavior of the coupled oscillators array demonstrated that the phase differences between the oscillators can be varied up to about pi/2 by giving the frequency changes from the injection locking frequency to the oscillators except of the first one. The oscillator mounted with the varactor diode for wide tuning range exhibited the property suitable for constructing the unilaterally coupled array. In the experiments, at X-band, the electromagnetic wave radiated from the five element array was successfully scanned.

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In order to realize high power circularly polarized microwave and millimeter-wave radiating sources, spatial power combining of circularly polarized active antennas have been investigated. Circularly polarized active antennas with single point feeds were designed for this purpose, and were measured their circular polarization characteristics under their single active antenna operation. In mutual synchronization for both cases of radiative coupling and transmission-line coupling between two active antennas, the relation of synchronized frequency and output radiation power versus the interval between the active antennas was measured to obtain the synchronization characteristics. Spatial power combining experiment was carried out for one and two dimensional arrays of radiative coupling and for one dimensional arrays of transmission-line coupling. The experimental results show that spatial power-combining of low axial ratios and high combining efficiencies could be attained.

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In order to obtain a stable signal in the higher frequency range, second harmonic oscillators injection-locked subharmonically have been investigated. The oscillator had the optimum load impedance for second harmonic generation at both the fundamental frequency and the second harmonic frequency so that high harmonic output wave could be obtained with the frequency around 17GHz. By experiments on the oscillator injection-locked subharmonically with factor of 1/2 , the stabilization of the oscillation frequency and the degradation of the phase noise were confirmed. The measurements of the locking bandwidth with the injection power level showed that the bandwidth increases with decreasing the subharmonic factor.

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An axially symmetrical Fabry-Perot resonator with active devices inserted in a dielectric has been investigated for power combining of many more devices in microwave and millimeter wave frequency range. By previous experiments, it was shown that the output power of the individual devices can be combined efficiently when the spacing between the adjacent devices is nearly equal to half wavelength at the operating frequency. The active devices are inserted in the dielectric, in which the wavelength is shorter than that in free space, in order to increase the number of the devices. The device mount was designed by numerical calculation using the boundary element method. In the experiments at X-band, the fabricated combiners with Gunn diodes oscillated stably, and almost perfect power combining was achieved in both the cases of the sixteen diodes and the twenty-two diodes.

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In order to scan a radiation beam more widely, the phased array behavior of active antennas radiating a second harmonic output wave has been investigated. In numerical calculations of a coupled oscillator system modeled on the active antenna array, when the oscillators are coupled by only the fundamental output wave, the variation of the phase differences of the second harmonic output waves between the adjacent oscillators can reach up to 2π, which is twice as much as in the case of the phased array outputting the fundamental wave. By the experiments using the two and four elements arrays, the calculated results were confirmed and the wider scanning ranges of the second harmonic output wave than that of the fundamental output wave were obtained.

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The active phased array antenna with self-oscillating harmonic mixers has been investigated. The active antenna is composed of a patch antenna receiving RF signal and a parallel feedback type oscillator which operates as the self-oscillating harmonic mixer, and down-converts the received RF signal into IF signal. The oscillator has two ports for output of the oscillated power and for injection signal so that the oscillators can be coupled unilaterally without other nonreciprocal components. In the unilaterally coupled array, the phase differences between the local oscillating signals can be varied by changing the local free-running frequencies of the self-oscillating mixers. The receiving directivity can be controlled by combining the IF signals from the individual active antennas. In the experiment using the two-element array, the receiving pattern was scanned successfully. © 2002 IEEE.

DOI： 10.1109/EUMA.2002.339424

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The new traveling-wave power divider/combiner with the coplanar waveguide probes has been presented. The divider/combiner is composed by connecting successively the dividing units which consist of the coplanar waveguide probe-pair inserted into the rectangular waveguide and the thin narrow section. By the experiment at X-band, it was confirmed that the four-and six-way divider/combiners had the wideband characteristics conparable to the divider/combiner with the coaxial probes. In the four-and six-way dividing-combining systems, the bandwidth wider than 1.7GHz was obtained.

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The phased array behavior of active antennas with self-oscillating mixers has been investigated. The active antenna is composed of a patch antenna and a two-port oscillator with the unilateral characteristics which operates as the self-oscillating mixer, and down-converts received RF signal into IF signal. In the unilaterally coupled array of the active antennas, the phase differences between local oscillating signals can be obtained by changing the local free-running frequencies of the antennas. When all the IF signals from the individual active antennas are combined, the receiving directivity can be controlled. In the experiment using the two-element array, the receiving pattern was scanned successfully.

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A power combining technique using a Fabry-Perot resonator with many more active devices is investigated. The Fabry-Perot power combiner consists of two mirrors with a circular groove mounted with the active devices. The power combiner has an axially symmetrical structure and operates at an axially symmetrical TEM01n mode so that uniform device-field coupling required for perfect power combining can be realized. By numerical calculation using the boundary element method, it was shown that high combining efficiency can be obtained when the active devices are mounted in the circular groove of larger radius on either of the two mirrors. In experiments at X-band, power combining efficiency over 90% was obtained for the case of twelve devices on either of the mirrors and the output powers of the twenty or twenty-four devices on both the mirrors were almost perfectly combined.

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Power combining techniques using the ladder oscillator which is mounted with multiple Gunn diode along the hyper NRD guide have been demonstrated. In order to determine the distances between the adjacent diodes, the susceptance of the diode with the mount structure is necessary, so that the value of the susceptance was estimated from the measured oscillator characteristic of the oscillator mounted with the two diodes. The oscillators mounted with the more than two diodes were designed by the derived value of the susceptance. In experiments at X-band, almost perfect power combining of the outputs of the three or four diodes was obtained.

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The new traveling-wave power divider with the coplanar waveguide probes is investigated. The divider is composed by connecting successively the dividing units which consist of the coplanar waveguide probe-pair inserted into the rectangular waveguide and the thin narrow section. By the experiments on the four- and six-way dividers, the wideband characteristics comparable to the divider with the coaxial probes is demonstarted.

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A conical-radial wave power divider/combiner has been developed exmerimentally, which has broadband and low loss characteristics required for the power dividing-combining system. Electromagnetic field analysis is necessary for the optimum design of the divider/combiner. In this paper, numerical calculation is carried out using the FD-TD method in cylindrical coordinate system. The divider/combiner is divided into three parts, that is, a converting part from the coaxial line to the radial line through the conical line, a matching window, and peripheral coaxial probes. The scattering parameters of the individual parts are calculated by FD-TD method. The reflection coefficients of the dividers are obtained by combination of these parameters using an equivalent circuit, and are compared with the measured results.

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An axially symmetrical Fabry-Perot oscillator with active devices inserted in a dielectric is investigated in order to combine output powers of many more devices in the microwave and millimeter wave frequency range. The mount structure of the active devices was designed by a numerical calculation using the boundary element method. In the experiments at X-band, the oscillator operated stably when the resonator length of the Fabry-Perot resonator was varied, and almost perfect power combining of sixteen Gunn diodes was achieved. © 2000 IEEE.

DOI： 10.1109/EUMA.2000.338777

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In order to not only obtain a higher frequency radiation but also scan its beam more widely, an active phased array using second harmonic generation is investigated. The active antenna consists of a patch antenna radiating the second harmonic wave, and a FET oscillator which plays owo roles in fundamental oscillator and frequency multiplying. The structure of a coupling network between the adjacent active antannas suitable for the phased array behavior is found by measuring the external quality factor looking at the coupling line of the active antenna. In the experiments, the radiated beam of the second harmonic waves from the two or three element active antenna array were scanned more widely than that in the case of the fundamantal wave radiation.

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In order to realize an active phased array antenna, a phased array behavior of a microwave unilaterally coupled active antenna array which is controlled by frequency changes of the oscillators has been investigated. The active antenna array is couposed by coupling active antennas which consist of patch antennas and parallel feedback type oscillators with unilateral characteristics. A tuning range of the free-running frequency of the oscillator is widened by inserting a varactor diode into a feedback loop of the oscillator. An experiment of a system of two oscillators without antennas has confirmed the phased array behavior. Electromagnetic waves radiated from two, three and four active patch antenna array were successfully scanned.

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A Gunn diode oscillator using a Hyper NRD guide have been investigated. The operating mode of the Hyper NRD guide is lower order than the ordinary NRD guide case, so the mode conversion to undesired modes can be supperssed. In experiments at X-band for the oscillator by mounting a single or double Gunn diode in the dielectric strip of the Hyper NRD guide, the oscillation frequencies could be varied by a movable shorting plane for the single diode case and a perfect power combining operation was obtained for the double diode case.

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In order to not only obtain a higher frequency radiation but also scan its beam more widely, an active phased array using second harmonic generation is investigated. The active antenna consists of a FET oscillator which plays two roles in fundamental oscillation and frequency multiplying, and the patch antenna resonated at the second harmonic frequency. In the experiments, the radiated beam of the second harmonic wave from the two element active antenna array was scanned more widely than that in the case of the fundamental wave radiation. © 1999 IEEE.

DOI： 10.1109/EUMA.1999.338375

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A unilateral coupling scheme for two-dimensional active antenna arrays was developed. Each oscillator is coupled to one of its neighbor oscillators unilaterally in a comb-like arrangement. The phase shifts along both axes of the array can be controlled by adjusting the frequency of only the back oscillators. Two paths, which are different in length and each contains an amplifier, were employed for unilateral coupling. Turning on the desired one out of two amplifiers, one can change the range in which the phase shift can be varied. In a 2×2 experimental oscillator array, the main beam could be scanned 40° in H-plane and 25° in E-plane totally. © 1999 IEEE.

DOI： 10.1109/EUMA.1999.338342

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In coupled oscillator arrays, it is possible to control the inter-element phase shift up to 180 degrees by free-running frequency distribution based on injection-locking phenomenon. In this paper, a new technique to control the inter-element phase shift electronically up to the maximum extent of 360 degrees is reported. Oscillators are unilaterally coupled to the preceding oscillator through one of the two paths, which differ from each other 180 degrees in electrical length and each includes an amplifier. Turning on the desired amplifier one can control the phase shift either -180 degrees to 0 degrees or 0 degrees to 180 degrees. The technique was applied in a three-element oscillator array each coupled to a patch antenna via a round aperture. The radiation beam of the array could be scanned 47 degrees in total.

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Design of circularly polarized active antennas of dual-fed square patch type is given, and spatial power combining and phased array operation of the antennas have been successfully achieved. In a phased array experiment of the arrays with two and three active antennas by the method of varying their free-running oscillation frequencies, we obtained the scan angles from -12 degrees to + 13 degrees and those from -13 degrees to + 13 degrees, respectively and good axial ratios together with high spatial power-combining efficiencies.

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In order to derive high radiated power in the higher frequency range, the spatial power combining of the second harmonic wave using the active antenna array is investigated. The active antenna consists of a FET oscillator which plays two roles in fundamental oscillation and frequency multiplying, and the patch antenna which has the measured optimum impedance for second harmonic generation. In the experiment, two active antennas were synchronized and their second harmonic output powers were combined in free space.

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A unilateral coupling scheme for two-dimensional active antenna arrays was developed. Each oscillator couples to a single oscillator unilaterally in a comb-like arrangement. The phase shifts along both axes of the array can be controlled by the free-running frequency of the initial oscillators under injection locking phenomenon. Two paths, which are different in length and each contains an amplifier, were employed for unilateral coupling. Turning on the desired amplifier, one can shift the range in which the phase shift can be varied. In a 2×2 experimental oscillator array, the main beam could be scanned 40° in H-plane and 25° in E-plane totally.

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DOI： 10.1109/APMC.1999.828044

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Full-wave FD-TD analysis has been carried out for coaxial probes inserted into waveguides. Both single and symmetrically placed paired coaxial probe structures have been discussed and we have revealed the relation between equivalent circuit parameters and structural parameters of the coaxial probes including cases for large diameter and extension length, which is usuful for practical waveguide circuit design. The equivalent circuit parameters calculated from the scattering parameters agreed well with corresponding measured data. From the calculated field in a waveguide, field concentration at sharp edges of probe sole or base, which ought to be taken into account for high power application design has been also discussed. Besides, amplitudes of higher order modes in waveguides excited by coaxial probes or pairs of coaxial probes has been calculated so as to estimate the range beyond which higher order modes decay sufficiently. This estimation is necessary for simple and easy design of probe using circuit theory.

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In order to realize the spatial power combining and the phased array behavior of microwave and millimeter-wave circularly polarized active antennas, we designed and manufactured circularly polarized active antennas. We measured their circular polarization characteristics in single active antenna operation, and the mutual synchronization characteristics of two active antennas with similar characteristics to obtain experimentally the relation between the antenna separation and the coupling phase. We carried out phased array experiments using two and three active antennas, and attained the scan angles from -12° to +13° and those from -13° to +13°, respectively, and good axial ratios together with high spatial power-combining efficiencies.

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We have investigated an active phased array antenna which is constructed by connecting each oscillator of a unilaterally coupled system to a slot antenna. The unilaterally coupled oscillators system can be composed by the coupling oscillators with unilateral characteristics which consist of FET amplifiers and directional couplers. The slot antenna is electromagnetically coupled to FET oscillators and the array antenna can operate as the phased array by controlling free-running frequencies of the oscillators. Actually we have successfully scanned electromagnetic waves radiated from two antenna array and three antenna array.

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In order to combine spatially powers of active devices using an active antenna array, we have investigated a mutual locking behavior of active slot antennas, which are composed of microstrip oscillators using Gunn diodes coupled electromagnetically to slot antennas. We measure characteristics of the microstrip oscillator and the slot antenna electromagnetically coupled to the microstrip line, respectively, so that we design the active slot antenna. A measured radiation pattern whose the active slot antenna is fabricated actually is shown. A coupling coefficient between the active antennas coupled radiatively is caluculated analytically and its phase is compared whith results of experiments on the mutual locking of two antenna array and three antenna array.

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Several types of transmission-line coupling are analyzed to use in one- and two-dimensional active antenna arrays, and a method is developed to scan the beam of the arrays using the mutual locking theory. To compensate the undesired effect of strong radiative coupling of the nearest neighbor elements on the phased array performance, addition of resistive stubs to the end elements is proposed. In a 1×4 array it was observed that after the connection of resistive stubs, the scanning range of the array increased considerably. The effect of oscillator amplitudes on the phased array behavior is explored numerically. In the experiments main beam of 2×2 and 3×3 active antenna arrays were steered up to 25° and 15°, respectively in the H-plane.

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Techniques for phased array operations of active antenna arrays are reviewed. The active antennas which are composed of active devices and antennas are coupled with their adjacent ones in the array so that they can operate at a single frequency due to locking phenomena and their output powers are combined spatially. Various methods for the phased array behaviors by controlling phases of injection signals or frequency changes of the active antennas are described.

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In order to realize an active phased array antenna, we have investigated a phased array behavior of a microwave unilaterally coupled oscillators system which is controlled by frequency changes of the oscillators. The unilaterally coupled oscillators system can be composed by coupling oscillators with unilateral characteristics which consist of FETs and directional couplers. By approximate and numerical analyses, we show that the phased array behavior can be realized by varying the frequencies changes of the oscillators except the first oscillator. An experiment on a system of three oscillators has confirmed the phased array behavior. Finally, we have scanned electromagnetic wave using two patch antennas array connected to the FET oscillators.

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Full wave FD-TD analysis has been carried out for single or paired coaxial probes inserted into a rectangular waveguide, including cases for large diameter and extension length of probe structure. For the probe structures, field distribution in waveguide and coaxial probe were calculated. Reflection coefficient and equivalent admittance of the probe agreed very well with experimental results. Maximum operating power which ought to be taken into account for high power application has been also discussed.

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Full wave FD-TD analysis has been carried out for single or paired coaxial probes inserted into a rectangular waveguide, including cases for large diameter and extension length of probe structure. For the probe structures, field distribution in waveguide and coaxial probe were calculated. Reflection coefficient and equivalent admittance of the probe agreed very well with experimental results. Maximum operating power which ought to be taken into account for high power application has been also discussed.

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We investigate an axially symmetrical Fabry-Perot oscillator with active devices inserted in a dielectric substrate for power combining of many more devices in microwave and millimeter wave frequency range. Empirically in this oscillater, efficient power combining is caused when it oscillates approximately at the frequency which corresponds to the wavelength equal to twice the spacing between devices. The wavelength in the dielectric is shorter than in free space, so we tried to insert the devices in the dielectric substrate in order to increase the number of the devices. By measuring the oscillation frequency of the oscillator with twelve devices at X-band, we confirmed that the spacing between devices was about half wavelength in the dielectric. And we achieved almost perfect power combining of sixteen devices.

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In order to realize an active phased array antenna, we have investigated a phased array behavior of a microwave coupled oscillators system which has locking sources at both ends and is controlled by phases of the injection signals and frequency change of the oscillator. By approximate and numerical analyses, we show that the phased array behavior can be realized controlled by phase differnecs between two injection signals and frequency change of the oscillator at one end. An experiment on a system of waveguide type oscillators has confirmed the phased array behavior. Finally, we have scanned electromagnetic wave using five active patch antennas array mounted with Gunn diode.

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We investigate an axially symmetrical Fabry-Perot oscillator with many more active devices operating in axially symmetrical TEM_01n mode, which has an excellent feature of uniform device-field coupling required for high power combining efficiency. By numerical calculation using the boundary element method, it was shown that high combining efficiency can be obtained when a circular groove of larger radius is installed on either the plane mirror or the concave mirror. In experiments at X-band, power combining efficiency as high as 90% was attained for the case of twelve devices on either of the mirrors and almost perfect power combining of twenty or twenty-four devices mounted on both the mirror was achieved.

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We propose an axially symmetrical Fabry-Perot multiple-device oscillator operating at an axially symmetrical TEM(01n)-mode, which has an excellent feature of uniform device-field coupling required for high efficiency power combining. By carrying out the boundary element analysis, it is shown that a plane-mirror output structure is remarkably advantageous compared with a concave-mirror output structure to obtain an adequate output coupling and to enable stable operation characteristic with respect to the axial mode number n. Experiments in X-band confirmed this excellent performance and achieved almost perfect power combining of efficiency as high as 106% and 99% for six- and eight-device case, respectively.

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In order to realize an active phased antenna array, we propose a new phased coupled microwave oscillators system which has a phase-locking source at one end and is controlled by fequency change of the oscillator at the other end. We derive a fundamental equation from a generalized model of the system and give an approximate condition for uniform phase difference between neighboring oscillators. In addition, exact behaviors of the system are obtained numerically. An experiment on a system of three waveguide type oscillators has confirmed the phased array behavior. Actually we have scanned electromagnetic wave using a two active patch antennas array in X-band.

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We propose a new waveguide type traveling-wave microwave power divider that is adequate for high power applications. The divider is composed of multiple stages of reflectionless dividing units, each having two output ports. Design formulas for reflectionless equal-power dividing are first derived. Structural parameters for wideband design of two- to six-stage dividers are then obtained by means of numerical analyses based on an equivalent circuit Comparison of experiments at X-band shows good qualitative agreement with the analyses. Typical measured bandwidth for relative divided powers deviation of less than ±0.5 dB was 2.7 GHz, and that for -20 dB return loss was more than 3.2 GHz for the four-stage (eight-way) divider. The divider presented here has excellent features
the bandwidth for equal-power dividing decreases very little and the bandwidth for low return loss increases with increasing number of the dividing stages. It also has advantages of low insertion loss and flexibility over the number of the dividing stages. Index Terms—Microwave, power dividing, power combining, traveling-wave operation. © 1995 IEEE

DOI： 10.1109/22.363014

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A fundamental study on the phase control of two-dimensional oscillator arrays is reported.Nonlinear differential equations describing the two-dimensional oscillator array behavior are derived and applied to the class of nearest neighbor coupled oscillators.Those equations are linearized to obtain a relationship between the oscillator phases aiad their free-running frequencies. A nonhnear integration routine was used to simulate the actual oscillator behaviors to compare with the theoretical results.It is shown that detuning the free-running frequencies of the symmetric elements in the same amount but in opposite directions establishes a constant phase progressions along the both directions.

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We propose an axially symmetrical quasi-optical multiple-device oscillator using a Fabry-Perot resonator which consists of a plane mirror and a concave mirror.The plane midrror has a circular groove mounted with many solid-state devices so that efficient power combining can be achieved using axially symmetric TEM_01n> or TEM_11n> mode due to uniform device-field coupling. We calculated the electric and magnetic field in the resonater by boundary element method in order to investigate the effect of the groove and a circular output window installed on the plane or the concave mirror.Experiments were carried out at X-band for the case of octuple-device oscillator and satisfactory agreement with the calculation was obtained.By use of a circular output window on the plane mirror,a remarkable increase in power combining efficiency was attained

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Basic studies on the phased-array behaviors of two types of chain coupled microwave oscillator systems are presented.The first type is a unidirectionally coupled oscillator chain in which one end oscillator is different from the others in free-running oscillation frequency.The second type is a mutually coupled oscillator chain in which the free-running oscillation frequencys of both the end oscillators deviate oppositely from the others.It is analytically shown that after attaining synchronization,the systems can operate as active phased arrays which are controlled by the oscillation frequency difference.Experiments on both the systems using three Gunn oscillators agreed well with the analyses.

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J-GLOBAL

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The use of an asymmetric Mach-Zender interferometric amplitude modulator to measure a relatively low frequency electric field strength is described. The sensitiviy of an electric field sensor using a Ti: LiNbO3 optical modulator is strongly affected by the shape of a electrode (probe antenna). To measure the low frequency electric field, a probe antenna of wide effective area is more useful than the usual dipole antenna. As proof of this, the optical modulator was fabricated with a plate-type probe antenna and the usefulness of this antenna tested for measuring low frequency electric field strength.

DOI： 10.1049/ip-j.1993.0023

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

In order to develop a new possibility of a spatially power combining oscillators array,we discuss behavior of a one- dimensional coupled oscillators system which has two locking signals with different phases injected at both the ends.We obtain differential equations which describes the system behavior and calculate both the amplitude and phase responses to variation of the phase difference between two injection signals under various conditions.Especially the effect of relative magnitude of injection signals on the phased-array characteristics and the stability of an operating mode against phase disturbance are numerically investigated.A fundamental experiment on the phased array characteristics of three Gunn oscillators system were carried out and the theoretical predictions were confirmed with satisfactory agreement.

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Authorship：Lead author   Language：English   Publisher：TAYLOR & FRANCIS  

We have investigated a waveguide bend having enhanced curvature with reduced loss. The waveguide width is made wider toward the inner side of the bend. The numerical analysis, by means of the beam propagation method, showed that the loss of the proposed bend is lower than that of an abrupt bend or a smooth bend of constant curvature. For a typical waveguide, we have optimized the structure of the bend and achieved one order of loss reduction in comparison with an abrupt bend of the same angle.

DOI： 10.1080/01468039008202922

Web of Science

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CiNii Article

CiNii Books

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Authorship：Lead author   Language：Japanese   Publisher：レ-ザ-学会  

DOI： 10.2184/lsj.15.734

CiNii Article

CiNii Books

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Authorship：Lead author   Language：Japanese   Publisher：電子通信学会  

CiNii Article

CiNii Books

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Event date： 2022.9.6 - 2022.9.9

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2022.3.15 - 2022.3.18

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2022.3.15 - 2022.3.18

Language：Japanese   Presentation type：Oral presentation (general)  

Event date： 2021.9.14 - 2021.9.17

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2021.5.20

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2021.3.9 - 2021.3.12

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2021.3.9 - 2021.3.12

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2021.3.9 - 2021.3.12

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2020.11.28 - 2020.11.29

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2020.10.24

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2020.6.4

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2020.3.17 - 2020.3.20

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2019.9.10 - 2019.9.13

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2019.5.16

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2019.3.19 - 2019.3.22

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2018.9.11 - 2018.9.14

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2018.5.24 - 2018.5.25

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2018.3.20 - 2018.3.23

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2018.3.20 - 2018.3.23

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2017.12.2 - 2017.12.3

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2017.5.18 - 2017.5.19

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2017.5.18 - 2017.5.19

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2017.3.22 - 2017.3.25

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2017.3.22 - 2017.3.25

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2017.3.22 - 2017.3.25

Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2016.9.20 - 2016.9.23

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2016.5.19 - 2016.5.20

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2016.5.19 - 2016.5.20

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2015.9.8 - 2015.9.11

Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2014.3.18 - 2014.3.21

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2013.10.19

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岡山市  

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Event date： 2013.9.17 - 2013.9.20

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2013.5.30 - 2013.5.31

Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2013.3.19 - 2013.3.22

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2013.3.19 - 2013.3.22

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2012.9.11 - 2012.9.14

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：富山市  

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Event date： 2012.3.20 - 2012.3.23

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2011.12.15 - 2011.12.16

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2011.10.22

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：広島市  

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Event date： 2011.9.13 - 2011.9.16

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：札幌市  

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Event date： 2011.3.14 - 2011.3.17

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2010.12.16 - 2010.12.17

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2010.10.23

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岡山県総社市  

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Event date： 2010.10.23

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岡山県総社市  

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Event date： 2010.10.23

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岡山県総社市  

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Event date： 2010.10.23

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岡山県総社市  

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Event date： 2010.10.23

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岡山県総社市  

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Event date： 2010.5.13 - 2010.5.14

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2010.3.16 - 2010.3.19

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：仙台市  

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Event date： 2010.3.16 - 2010.3.19

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：仙台市  

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Event date： 2010.3.16 - 2010.3.19

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：仙台市  

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Language：Japanese   Presentation type：Poster presentation  

Venue：宇部市  

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Language：Japanese   Presentation type：Poster presentation  

Venue：宇部市  

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Event date： 2009.10.17

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：広島市  

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Event date： 2009.10.17

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：広島市  

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Language：Japanese   Presentation type：Oral presentation (general)  

Venue：新潟市  

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Event date： 2009.5.28

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：岡山市  

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Venue：愛媛県松山市  

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Venue：愛媛県松山市  

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Event date： 2009.3.17 - 2009.3.20

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：愛媛県松山市  

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Event date： 2008.12.12

Presentation type：Oral presentation (general)  

Venue：富山市  

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Event date： 2008.11.21 - 2008.11.23

Presentation type：Poster presentation  

Venue：広島市  

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Presentation type：Poster presentation  

Venue：広島市  

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Event date： 2008.11.21 - 2008.11.23

Presentation type：Poster presentation  

Venue：広島市  

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Event date： 2008.10.25

Presentation type：Oral presentation (general)  

Venue：鳥取市  

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Event date： 2008.10.25

Presentation type：Oral presentation (general)  

Venue：鳥取市  

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Event date： 2008.10.25

Presentation type：Oral presentation (general)  

Venue：鳥取市  

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Event date： 2008.10.25

Presentation type：Oral presentation (general)  

Venue：鳥取市  

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Event date： 2008.10.25

Presentation type：Oral presentation (general)  

Venue：鳥取市  

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Event date： 2008.10.25

Presentation type：Oral presentation (general)  

Venue：鳥取市  

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Event date： 2008.9.18 - 2008.9.20

Presentation type：Oral presentation (general)  

Venue：広島市東広島市  

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Venue：神奈川県川崎市  

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Presentation type：Oral presentation (general)  

Venue：神奈川県川崎市  

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Presentation type：Oral presentation (general)  

Venue：神奈川県川崎市  

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Presentation type：Oral presentation (general)  

Venue：大阪府豊中市  

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Presentation type：Oral presentation (general)  

Venue：北九州学術研究都市  

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Event date： 2008.3.18 - 2008.3.21

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Venue：北九州学術研究都市  

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Event date： 2008.3.18 - 2008.3.21

Presentation type：Oral presentation (general)  

Venue：北九州学術研究都市  

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Event date： 2007.10.20

Presentation type：Oral presentation (general)  

Venue：広島県東広島市  

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Event date： 2007.9.13

Presentation type：Oral presentation (general)  

Venue：鳥取市  

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Event date： 2007.9.10 - 2007.9.14

Presentation type：Oral presentation (general)  

Venue：鳥取市  

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Event date： 2007.8.29

Presentation type：Oral presentation (general)  

Venue：福岡市  

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Event date： 2007.5.22

Presentation type：Oral presentation (general)  

Venue：兵庫県姫路市  

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Event date： 2007.3.21

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Venue：名古屋市  

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Event date： 2007.3.20

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Venue：名古屋市  

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Event date： 2007.3.20

Presentation type：Oral presentation (general)  

Venue：名古屋市  

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Event date： 2006.10.21

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Event date： 2006.9.23

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Event date： 2006.9.22

Venue：金沢市  

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Event date： 2006.9.22

Venue：金沢市  

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Event date： 2006.9.20

Venue：金沢市  

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Event date： 2006.9.19

Venue：金沢市  

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Event date： 2006.8.25

Venue：中華人民共和国成都  

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Event date： 2006.5.18

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Event date： 2006.3.26

Venue：東京都世田谷区  

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Event date： 2006.3.25

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Event date： 2006.3.24

Venue：東京都世田谷区  

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Event date： 2004.9.24

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Event date： 2004.9.9

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Event date： 2004.9.9

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Event date： 2004.8.5

Venue：中華人民共和国ハルピン  

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Event date： 2004.7.23

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Event date： 2004.5.14

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Event date： 2004.3.22

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