川﨑 繁男

This paper proposes a novel rectifier design method using a standard 0.18 mu m CMOS MMIC and a GaN (Gallium Nitride) diode by hybrid semiconductor integrated circuit (HySIC) technology. The target RF input power is around 10W at 5.8 GHz and output DC power is 2-3W. To achieve such high input/output power with small CMOS chip, low impedance and wide thin-fiIm micro-strip (TFMS) lines are used as impedance matching circuits. To protect capacitors from high voltage generation, series capacitor pairs are used as DC block and RF short circuits. A high linearity 3-stage nMOS SPST switch is also employed for the impedance match tuning. The GaN diode is modeled by measurement, and designed to be connected via eight bonding wires. The simulation results show that input return loss is lower than -14 dB, power efficiency is around 30% with 10 w RF input. The chip size is only 1.2 mm x 2.3 mm.

In this letter, a wireless sensor network system powered by microwave power transmission (MPT) technology within a prototype reusable spacecraft is proposed and evaluated. The evaluation was based on a 5.8 GHz, 50 W class MPT integrated with a 2.4 GHz band wireless communication system. Experiments to evaluate energy balance under 25 cm line-of-sight conditions and to test multi-sensor operation under non line-of-sight conditions within the prototype spacecraft, called a reusable vehicle test (RVT).

This paper presents the enhancement and optimization of a backscatter radios coverage, by using special designed waveforms for a dedicated WPT path, the backscatter radio is built using a specific frequency path for powering up the device, and several waveforms are tested to power up the overall systems, those include multi-sines and modulated signals. It was proved that a multisine signal with 0 degrees phase between the tones can produce better DC values when compared with a single tone excitation with same input power. With the use of modulated signals it was shown that, compared with CW, yielded better results in efficiency.

Wireless Communication and Power Transmission (WiCoPT) systems can transfer data and power, simultaneously. This paper investigates the impact of the modulation scheme and input power on rectifier RF-DC power conversion efficiency for such systems. As the reference, we use the same rectifier with continuous wave (CW) input signal. The paper introduces simulation and measurement results to clarify the impact of QPSK/16 QAM modulated input signals with various symbol rates and input powers on the efficiency. The efficiency exhibits three characteristics depending on the input power. The efficiency drastically degrades in the high input power region. On the other hand, rectifier efficiency is significantly enhanced in the lower input power region (basically start-up region). In the middle input power region, signal modulation slightly improves the efficiency. We also show that the efficiency depends on the symbol rate of the input signal.

Wireless sensor networks depend strongly on the battery duration, creating a passive sensor network scheme is one of the key strategies for IoT and or space oriented WSN systems. One of the possibilities for implementing this is to use backscatter radios, which uses a mechanism for switching the antenna load between two values and with that implement a simple and low power modulation scheme. Nevertheless, depending on the load, the energy harvesting mechanism is degraded in one of the impedance loads. This paper presents a rectifier design to harvest electrical energy for powering WSN's in both load conditions, by using two different frequencies. We found that, regarding the effect on the RF-DC conversion by modulation, almost no degradation was observed by changing modulation method under the low peak-to-average conditions.

PROCYONは,超小型衛星による小惑星フライバイ探査ミッションを目的として,はやぶさ2のピギーバック搭載機会である2014年12月の打ち上げを目指している.超小型衛星による深宇宙探査ミッションは,大型衛星とは異なる信頼性基準,コストのバランスによって成立させる必要がある.特に搭載重量や発生電力の制約条件は大きく,従来の宇宙用通信コンポーネントの設計概念を大きく変えて積極的な民生部品の活用と小型軽量化に最適な技術の導入が不可欠である.本稿では,PROCYON通信系構成,並びに,各コンポーネントの詳細を紹介する.

Copyright 2014 IEICE. This paper demonstrates experimental evaluation results of a wireless sensor network system inside a reusable rocket. Major requirements to realize the reusable rocket for future space development, light weight, low cost, and frequently operation such as planes. Wireless system instead of conventional wired electric system is strongly demanded. To validate effectiveness of a 920-MHz band ZigBee network system, a bread board model of 920-MHz band transceiver is designed and fabricated. Also, PC application is developed for the measurement of the sensor data. Four time slots are utilized for robust communication. Received signal strength indicator (RSSI) and packet error rate (PER) is measured using the reusable vehicle test (RVT).

This research proposes an X-band high efficiency onboard SSPA (solid-state power amplifier) for deep space missions by focusing on GaN (gallium nitride) HEMT (high electron mobility transistor) whose remarkable material properties, such as high thermal conductivity, wide band gap, and high breakdown voltage, are suitable for high power and high efficiency applications. Developing a high efficiency onboard SSPA is one of the great issues when we consider some missions toward Mars, Jupiter, and much farther planets because of the requirements of both ultra-long distance communication and low power consumption. As a first step toward developing a SSPA for deep space, a breadboard model is fabricated based on preliminary design. It consists of a buffer amplifier, a driver amplifier unit, a high power amplifier unit, an automatic level control unit, a variable attenuator, DC/DC convertors, and an over current protection unit. Here, GaN HEMT is used in both driver amplifier and high power amplifier units. RF (radio frequency) characteristics of these amplifier units are evaluated in experiments. The driver amplifier unit achieves output power of 31.5 dBm with power gain of 33.5 dB and less than -26 dBc of IM3 (third order intermodulation distortion) at P1dB (1dB compression point) at 8.425 GHz. Moreover, the maximum efficiency is up to 35.2%. On the other hand, the high power amplifier unit achieves 42.3 dBm of output power with 46.1% of PAE (power added efficiency) at P3dB (3dB compression point) at 8.40 GHz. In addition, the integrated GaN SSPA bread board model achieves the maximum output power of 41.9 dBm and the maximum total efficiency of 31.0% at 8.40 GHz. At least more than 5% total efficiency improvement can be seen compared to the previous onboard SSPAs. Moreover, space applicability of GaAs (gallium arsenide) MMIC (monolithic microwave integrated circuit), GaN HEMT and DC/DC convertor that are expected to be used in the SSPA are confirmed in total ionizing dose test.

In this study, a C band 20 W class GaN high power amplifier (HPA) for microwave power transmission (MPT) to sensor nodes in a spacecraft was designed. The weight of HPA was reduced by use of carbon graphite fixture. Measurement results of the small signal S parameters and large signal input output characteristics was shown. The measured S parameter corresponded with ADS simulation result and S21 was 10.6 dB at 5.8 GHz. The maximum output power was 44.2 dBm (26.3W) at 38.7 dBm RF input. The gain at 38.7 dBm RF input also was 6.1dB and gain compression from small signal condition was 4.5 dB. The lightweight GaN HPA was fabricated with carbon graphite fixture. © 2014 IEEE.

This paper proposes and demonstrates a dual-band Wireless Communication and Power Transmission (WiCoPT) system for a wireless health monitoring sensor network in Reusable Vehicle Test (RVT). The proposed dual-band WiCoPT system employs 25 GHz-band for uplink and data transfer and 5 GHz-band for downlink and power transfer, resulting in an efficient wireless sensor system. The paper also analyzed the interference between uplink signals and downlink signals on the IC tag. When the interference power level from the downlink is less than 0 dBm on the IC tag, the uplink performances are suitable. While the stable performance of the downlink are achieved when the interference power level from the base station is less than -25 dBm. Under the above conditions, each EVM value is less than 10%. In addition, the uplink performances slightly depend on the linearity of the output power amplifier. Those results provide us a design guide to realize the WiCoPT health monitoring system in the RVT.

The Wireless Communication and Power Transmission (WiCoPT) system, which can transfer data and power simultaneously, was proposed recently. This paper elucidates the RE-DC Power Conversion behavior of a rectifier suitable for a WiCoPT system with QPSK and 16QAM input signals. Using modulated signals instead of CW signals lowers the Power Conversion Efficiency (PCE) of the rectifier. The degree of degradation depends on the signal waveform. Input signals with low symbol-rates offer higher PCE than higher symbol-rate signals.

This paper evaluates a liability in use of modulated signal for microwave wireless power transmission. A microwave rectifier is designed and fabricated for the evaluation process. In design, inverse Class-F theory has been applied. Rectifier's RF/DC conversion efficiency is set as a Figure Of Merit (FOM). This FOM is acquired for different modulation type and bandwidth, in condition of equivalent total input RF power, through simulation and measurement. It is then compared with single tone RF CW signal's RF/DC conversion efficiency. For most modulation type and bandwidth, modulated signal had advantage in RF/DC conversion efficiency over CW achieving at highest 7.8% higher efficiency from measurement.

An S-band GaN on Si based 1 kW-class SSPA system for space wireless applications is proposed. Since high-efficiency and high-reliability amplifier is one of the most important technologies for power and communication systems in a future space base station on a planet, compact, high-power, and high-efficiency SSPA is strongly requested instead of TWTA. Thus, we adopt GaN on Si based amplifier due to its remarkable material properties. At the beginning, thermal vacuum and radiation test of GaN on Si are conducted so as to confirm the space applicability. Fabricated SSPA system consists of eight 200W HPAs and coaxial waveguide power combiner. It achieves high efficiency such as 57% of drain efficiency and 87% of combining efficiency when RF output power achieves more than 60 dBm. Furthermore, long-term stable operation and good phase noise characteristics are also confirmed.

GaN HEMT has been expected to satisfy requirements being used in space as amplifying devices of future high-efficiency onboard SSPAs due to its excellent properties such as robustness in a harsh environment, applicability to high frequency and high power operation. However, in X-band, the most important frequency band for space communication at this moment, evaluation of GaN HEMT to prove the space usage has not been conducted yet because ensuring a steady supply of X-band GaN HEMT devices is still difficult due to current collapse phenomena. Therefore, in this research, evaluation of RF characteristics affected by operational conditions and space environmental testing of X-band HPA using COTS GaN HEMT was conducted to secure the space usage.

In order to realize a compact beam switchable antenna, a 6×2 triple-plane sector antenna array is fabricated and tested. The array antennas are assembled with an polygon angle of 140°for seamless beam switch characteristics within -3 dB beam width. S-parameters of the amplifier module and radiation patterns of the active antenna array are measured. The amplifier module has 8 dB to 11 dB gain and over 15 dB isolation in output terminals. Seamless beam switch capability of 120°in -3 dB beam width is confirmed. © 2013 EurAAP.

This paper demonstrates fundamental evaluation results of a C-band rectifier using GaAs high-electron mobility transistor (HEMT) for microwave power transfer (MPT) inside of future reusable rockets. Rectifiers which utilize HEMT MMICs with hot-via interconnection structure are feasible solution to integrate with conventional wireless communication MMICs or sensor tags for low cost, light weight, and small components for space health monitoring system. Simulation of large signal S-parameters, measurement of rectification efficiency are conducted as a fundamental evaluation. Maximum rectification efficiency of 51.3 % at5.1GHz while the load resistance is 350 Ω is obtained from the measurement. © 2013 IEEE.

This paper describes a basic characteristic of a 7/8-GHz band circular stacked patch active integrated array antenna (AIAA) unit for solar sail embedding application. The proposed AIAA unit mainly consists of a 2×2 stacked circular patch array, two low noise amplifiers (LNAs) and two power amplifiers (PAs). The array has stacked structure for dual band operation. Moreover, the stacked patch array has orthogonal feed structure for better isolation characteristics between transmitter and receiver ports. Radiation patterns and S-parameters are evaluated by 3-D electromagnetic field simulation and measurement. © 2013 IEEE.

This paper demonstrates fundamental evaluation results of a 2-stacked chip-scale-packaged (CSP) power amplifier (PA) operating at Ka-band for high data rate communication inside of future reusable rockets. The PA monolithic microwave integrated circuit (MMIC) is fabricated by 0.15 μm GaAs high-electron mobility transistor (HEMT) process having hot-via interconnection structure. The proposed CSP has 2-stacked PA MMICs structure. RF signals are simply divided by the hot-via interconnection to the two MMCIs as well as DC biases. Measurement results of the proposed CSP show the gain and P1dB of 15.7 dB and 14.6dBm at 33.0 GHz, respectively. Comparing with non-stacked structure, the proposed CSP has 2.6 dB increment of P1dB while theoretical increment value is 3 dB. The proposed CSP is feasible to be used as a PA inside a future reusable rocket communication. © 2013 European Microwave Association.

This paper describes experimental demonstrations of a wireless power transfer system equipped with a microwave band communication function. Battery charging using the system is described to evaluate the possibility of the coexistence of both wireless power transfer and communication functions in the C-band. A battery-free wireless sensor network system is demonstrated, and a high-power rectifier for the system is also designed and evaluated in the S-band. We have confirmed that microwave wireless power transfer can coexist with communication function. © 2013 Satoshi Yoshida et al.

This paper analyzes RF-DC conversion efficiency in a rectifier, which receives FSK modulated signal. To clarify the degradation of the RF-DC conversion efficiency, a bridge-type rectifier, which employs four diodes, a 180-degree hybrid, and matching circuits, is investigated due to its broadband operation. The simulation results show the degradation is mainly caused by mixing operations with various frequency signals on the diodes used. Compared with conversion efficiency of the rectifier at the CW input signal operation, it is found that the efficiency degrades one-third when a FSK modulated signal is received. © 2013 IEEE.

The paper gives an overview of green technology for various categories of wireless power transfer and energy harvesting. Key components have been fabricated and evaluated for achieving high-performance microwave wireless power transfer in terms of high power and high efficiency of circuits and modules. Furthermore, experiments are presented on applications in wireless power supply and sensor networking. © 2013 IEEE.

This research proposes a wide power range operable 3-stage microwave rectifier for microwave wireless power transfer systems. The proposed rectifier is fabricated and measured at S-band. The proposed rectifier system consists of three rectifiers which has different operational range. Also, the system automatically selects the appropriate rectifier based on input power level. The rectifiers utilize HEMT instead of conventional schottky diodes for future integration into MMIC of wireless communication system. We have confirmed the system has over 30 dB range of input power with efficiency of over 25%. The concept of the system is effective for future microwave wireless power transfer system.

The multi-stage GaN amplifier with dual output power was explained for the application of microwave communication and power transmission. For the compact transmitter, single-tone and time-division operation is adopted in this study. The maximum output power of 91.8 W and the PAE around 55.4 % were obtained at 2.1 GHz in the high power transmitter operation. In the low power transmitter operation, the 4Mbps symbol-rate QPSK signal was achieved under the 19.2 W with 35 % PAE. By combining with a multi-stage rectifier in the receiver, the compact microwave communication and power transmission system can be realized.

In this work, we propose an active retrodirective antenna (RDA) array with polarization orthogonalizing features that uses only single antenna to transmit and receive in unit element. Hence this arrangement substantially reduces the size of the RDA and makes it feasible to be further implemented into a 2D array. The RDA array is able to retransmit the signal to the interrogator location with the signal that is orthogonally polarized to the interrogating signal. Furthermore, the proposed RDA is designed to be operated at 7.1GHz and 8.4GHz for the uplink and downlink of the satellite use, respectively.

本論文では,挿入損の低下とデバイス面積の小型化に有用なエア分離コプレーナ導波路について電磁界シミュレーションを行い,また,実際にMEMS (Micro electro mechanical systems)技術で作製した導波路の測定により,その有効性を検証した結果を報告する.信号線と接地面との間を空気で絶縁したエア分離コプレーナ導波路では,通常型コプレーナ導波路のように情報伝搬を担う高周波信号(RF : Radio frequency)の電界分布が誘電体内へ浸透する割合が少なく,導波路近傍の空気中に電界を閉じ込める効果が確認できた.この結果,従来設計よりも小さな占有面積内で作製した導波路においても,挿入損やアイソレーションの点でより優れたRF特性を示すことが明らかになった.また,本研究のエア分離コプレーナ導波路と静電駆動型マイクロアクチュエータを組み合わせることにより,機械的に導波路を駆動可能なRF-MEMSスイッチや可動導波路型の移相器などの様々なRF-MEMS受動素子の設計に応用可能であることを示した.

A small size low noise amplifier (LNA) module operating at 10GHz capable of a cryogenic cooling for radio astronomy is presented. The LNA has been fabricated using a 0.15 mu m gate length GaAs-based pseudomorphic high electron mobility transistor (pHEMT) monolithic microwave integrated circuit (MMIC) technology. This MMIC amplifier is a single chip consisting of three-stages was assembled in a module with a size of 38mm x 20mm. Using cryogenic equipments, the module was cooled down to a cryogenic temperature of 113 K, where the LNA achieved a high gain of 32.6 dB with a noise temperature of 71K (noise figure of 0.96 dB) at 10 GHz. The result obtained prove that the LNA presented is a suitable candidate for radio astronomy.

High power operable and miniaturized rectifier is one of the most important issues for spacecraft health monitoring system. This is because the flexibility of location, number, and power consumption regarding sensor tag is indispensable for reliable health monitoring. Previous single rectifiers focusing on schottky diode are unsuitable since operating at high power and considering integrated MMIC sensor tags are quite difficult. This research proposes GaN HEMT based rectifier for these issues due to its excellent properties such as structurally-preferable for MMIC, and suitable for high power operation. Design and evaluation of GaN HEMT based rectifier and an experiment using the rectifier and a thermal sensor with microwave wireless power transfer has been conducted. The proposed rectifier can be operated with 47 dBm input RF signal.

This paper presents the design, fabrication method, and measurement results of a low-loss ohmic-contact radio-frequency microelectromechanical systems (MEMS) switch. A novel bidirectional electrostatic actuation mechanism has been developed for a dual single-pole double-throw switch that could be used for an X-Ku-band low-temperature cofired ceramic switched-line-type phase shifter. A high-aspect-ratio deep reactiveion etching process and a thick gold-plating process were used to develop low-insertion-loss air-suspended MEMS waveguides and low resistive ohmic contacts. A typical insertion loss of 0.56 dB, a return loss of 19.4 dB, and an isolation of 51.4 dB were obtained at a Ku-band frequency of 12 GHz. [2010-0364]

Using a GaN high power amplifier and a double 4-inputport circular waveguide combiner, a 1kW S-band compact waveguide combiner unit operating at 2.1 GHz was assembled. The maximum power of 200W was realized with a Peltier device for heat sink. The high power amplifier unit shows the PAE of more than 50% with an AB-class operation under the temperature around 40 degrees C. The four GaN high power amplifiers were combined with the 4-inputports circular waveguide combiner, having an output power of 540W. Further the 1kW output power connecting two 500W-class power combiners was achieved. The combining efficiency of the 1kW-class power combiner unit was achieved to about 90 %.

In this paper, we review recent R&D topics inside Japan. As to devices, the topics cover GaN high power amplifier, RFIC, RF-MEMS tunable devices and metamaterials. In regard to systems, the topics cover millimeter wave communications, wireless power transfer system. Also we review some national projects funded by Ministry of Internal Affairs and Communications (MIC), Ministry of Economy, Trade and Industry (METI) and Ministry of Education, Culture, Sports, Science and Technology (MEXT). Then we conclude with activities of the Institute of Electronics, Information and Communication Engineers (IEICE).

技術の進歩と共に小型衛星に求められるミッション要求は高度化し,衛星は軽量化,低コスト化が求められている.カテゴリ-Aに属する月周回,ハロー軌道,ラグランジュ点などミッションでもより高性能な通信機器が要求されている.本研究では,カテゴリ-Aミッションの小型衛星に向けた,Sバンドトランスポンダを開発している.重量約1kg,寸法110×110×90mm^3,消費電力10w以下,ラグランジュ点でトランスポンダの検波を維持する.本開発により,カテゴリ-Aミッションの小型衛星設計に重要な役割を与える.本稿では開発している月・ラグランジュ点ミッションに向けた小型Sバンドトランスポンダを報告する.

This paper presents the design, fabrication method and measurement results on a low-loss Ohmic-contact RF-MEMS switch with a bi-lateral actuation for a Dual-SPDT switching system. The switch was fabricated based on the silicon bulk-micromachining technology and a layer-wise technique on an SOI wafer. We demonstrated a compatibility with electroplating and high aspect-ratio Deep-RIE process to have loss-less quasi-air-suspended MEMS waveguides and adequately thick gold layer for side-wall ohmic contact. Typical performance shows 0.56 dB insertion loss, 19.4 dB return loss and 51.4 dB isolation at the Ku-band frequency of 12 GHz. © 2010 IEEE.

The new design method for the low noise GaAs MMIC amplifier was described. The wide-band characteristic by the distributed amplifier was extended with low noise amplifier circuit technology in the first and even the second FET of the multi-stage FET amplifier. Through the experiment of the three-stage amplifier, the gain over 30 dB with NF below 2.0 dB over 7 to 14 GHz were obtained with the compact size of 3.3 mm x 1.7 mm. In addition, the gain of 30.9 dB and NF of 1.3 dB at 175 K were observed at 13 GHz. It is confirmed that the design method proposed in this study for the low noise MMIC amplifier can be effective in a communication system as well as to the radio astronomy.

A compact monolithic RF-MEMS switch (2mm x 4mm in area) with the dual single-pole-double-throw (SPDT) configuration was developed by using the SOI bulk micromachining technique. The electrostatic comb-drive actuators and the mechanically movable coplanar waveguides were implemented on the low-resistive active SOI layer and the high-resistive handle layer, respectively, to effectively allocate the device footprint. Electrical crosstalk between the waveguide and the electrostatic actuator was suppressed by using the buried silicon dioxide layer. At a driving voltage of 35 V, the switch exhibits an insertion loss of 3 dB and isolation of 30 dB at 12GHz.

Integration of Low Temperature Co-fired Ceramics (LTCC) technology and RF-MEMS is applicable for the realization of a small and cost-effective phase shifter. In this paper, a line-switched-type phase shifter with 3D waveguide structures and a novel design of RF-MEMS switch was demonstrated. The design method and fabrication process were reported with experimental results. The insertion loss and phase error of the 4-bit digital phase shifter on LTCC substrates with the size of 8mm x 8mm x 0.55mm was measured to be around 0.5dB/bit and less than 5% at 12.5GHz, respectively. The Dual Single-Pole-Double-Throw (D-SPDT) MEMS switch showed driving voltage of 40V, insertion loss of 0.9dB, return loss of 12dB and isolation of -29dB at 12.5GHz.

Compact and planar active integrated antenna arrays with a high power multi-stage amplifier were developed with effective heat sink mechanism. By attaching an aluminum plate to the backside of the creased amplifier circuit board, effective cooling can be achieved. The nonlinear behavior of the amplifier agrees well with the simulation based on the Angelov model. The high power amplifier circuit consisted of the three-stage amplifier and operated with an output power of 4 W per each element at 5.8 GHz. The 32-element active integrated antenna array stably operated with the output power of 120 W under the effective heat sink design. With a weight of 4 kg, the weight-to-output power ratio and the volume-to-output power ratio of the antenna array are 33.3 g/W and 54.5 cm(3)/W, respectively. Wireless power transmission was also successfully demonstrated.

This paper presents Japan's enterprising project to develop the active phased array antenna (APAA) for practical applications. The objectives are to realize the cost reduction, small volume and light weight of APAAs at K-band frequency. The key technologies for those purposes are partial drive of an array, Monolithic Microwave Integrated Circuits (MMIC), a phase shifter with Radio Frequency-Micro Electro Mechanical System (RF-MEMS) switch and relevant control circuits, and system integration of all devices. The structure and the research and development (R&D) schedule of the project are explained. The results of R&D activities so far are also described.

Development of a prototype of high power active integrated phased array antenna operating at 5.8GHz was introduced in this paper. in the AIPAA system for telecommunication as well as wireless power transmission, the two-stage amplifier operated with 27dBm and insertion loss of the LTCC phase shifter was with 2.6dB/bit. Under the wireless communication and high power transmission, the BER was measured with less than 10-4 in FSK.

Tethered solar power satellite (Tethered-SPS) consisting of a large panel with a capability of power generation/transmission and a bus system which are connected by multi-wires is proposed as an innovative solar power satellite (SPS). The power generation/transmission panel is composed of a huge number of perfectly equivalent power modules. The electric power generated by the solar cells at the surface of each module is converted to the microwave power in the same module. Since the modules are controlled by the bus system using wireless LAN, no wired signal/power interfaces are required between the modules. The attitude in which the microwave transmission antenna is directed to the ground is maintained by the gravity gradient force. The tethered panel is composed of individual tethered subpanels which are loosely connected to each other. This configuration enables an evolutional construction in which the function of the SPS grows as the construction proceeds. A scale model of the tethered subpanel can be used for the first step demonstration experiment of the SPS in the near future. (c) 2006 Elsevier Ltd. All rights reserved.

Com pact planar active integrated antenna arrays with a high power amplifier were developed with effective heat sink mechanism. Adding a heat extension function by an aluminum plate attached to the back side of the circuit substrate with the high power devices, a space of the air flow duct integrated in the array was created by a creased circuit substrate. Alternatively, the heat pipe was used for a compact heat sink operation. One of the high power amplifier circuits consists of the three-stage amplifier and operated with the output power of 4W at 5.8GHz. The 32-element active integrated antenna array stably generated the output power of over 100W. The weight-to-output power ratio was 33.3 g/W from the weight with about 4.0 kg and the volume-to-output power was 54.4 cm(3)/W.

An ultrasmall active integrated antenna 2.5 cm square was fabricated by combining an MMIC oscillator and planar slot antennas. The design of array antennas by simulation and analysis of their injection locking characteristics are presented. Beam steering and the effect of packaging are considered in the measurement, and the effect of the metal reflector plate behind the array antenna is studied. A small active integrated antenna is placed at the focal point of a parabolic antenna. Its operation as a receiving integrated antenna with a self-oscillating mixer for communication satellite is confirmed. © 2003 Wiley Periodicals, Inc.

This paper describes an illuminated MESFET model under the pulse modulation operation. The simulation and experimental results of the oscillator photodetector using the illuminated MESFET model were compared.

This paper reports an active integrated antenna which combines the antenna function with the millimeterwave MMIC technology. In addition to a high carrier frequency, the compactness of the circuit is extremely useful for applications to automobile radar and wireless LAN. To realize low-cost millimeter-wave subsystems, this paper describes an active integrated antenna making use of the slot antenna and the second harmonic of the FET oscillator. The input impedance of the slot antenna is included in the design of a strongly coupled active integrated antenna array. The oscillation frequency of the array was evaluated by a large signal analysis. In the case of a two-dement active integrated antenna using a harmonic, the second harmonic operating frequency of 39.3 GHz was obtained. The phase of the radiation of the fundamental mode was adjusted so that different radiation patterns for different modes were obtained. Also, in the uniplanar-type four-element array, a large signal analysis was carried out including the discontinuities in the coplanar waveguide. Through the present trial fabrication, the fundamental data for fabrication of millimeter-wave monolithic active integrated antennas were obtained.