Hang Liu Fei Wu
Keiji GOTO Toru KAWANO Ryohei NAKAMURA
Takahiro SASAKI Yukihiro KAMIYA
Xiang XIONG Wen LI Xiaohua TAN Yusheng HU
Anton WIDARTA
Hiroshi OKADA Mao FUKINAKA Yoshiki AKIRA
Shun-ichiro Ohmi
Tohgo HOSODA Kazuyuki SAITO
Shohei Matsuhara Kazuyuki Saito Tomoyuki Tajima Aditya Rakhmadi Yoshiki Watanabe Nobuyoshi Takeshita
Koji Abe Mikiya Kuzutani Satoki Furuya Jose A. Piedra-Lorenzana Takeshi Hizawa Yasuhiko Ishikawa
Yihan ZHU Takashi OHSAWA
Shengbao YU Fanze MENG Yihan SHEN Yuzhu HAO Haigen ZHOU
Ryo KUMAGAI Ryosuke SUGA Tomoki UWANO
Jun SONODA Kazusa NAKAMICHI
Kaiji Owaki Yusuke Kanda Hideaki Kimura
Takuya FUJIMOTO
Yuji Wada
Fuyuki Kihara Chihiro Matsui Ken Takeuchi
Keito YUASA Michihiro IDE Sena KATO Kenichi OKADA Atsushi SHIRANE
Tomoo Ushio Yuuki Wada Syo Yoshida
Futoshi KUROKI
Jun FURUTA Shotaro SUGITANI Ryuichi NAKAJIMA Takafumi ITO Kazutoshi KOBAYASHI
Yuya Ichikawa Ayumu Yamada Naoko Misawa Chihiro Matsui Ken Takeuchi
Ayumu Yamada Zhiyuan Huang Naoko Misawa Chihiro Matsui Ken Takeuchi
Yoshinori ITOTAGAWA Koma ATSUMI Hikaru SEBE Daisuke KANEMOTO Tetsuya HIROSE
Hikaru SEBE Daisuke KANEMOTO Tetsuya HIROSE
Zhibo CAO Pengfei HAN Hongming LYU
Takuya SAKAMOTO Itsuki IWATA Toshiki MINAMI Takuya MATSUMOTO
Koji YAMANAKA Kazuhiro IYOMASA Takumi SUGITANI Eigo KUWATA Shintaro SHINJO
Minoru MIZUTANI Takashi OHIRA
Katsumi KAWAI Naoki SHINOHARA Tomohiko MITANI
Baku TAKAHARA Tomohiko MITANI Naoki SHINOHARA
Akihiko ISHIWATA Yasumasa NAKA Masaya TAMURA
Atsushi Fukuda Hiroto Yamamoto Junya Matsudaira Sumire Aoki Yasunori Suzuki
Ting DING Jiandong ZHU Jing YANG Xingmeng JIANG Chengcheng LIU
Fan Liu Zhewang Ma Masataka Ohira Dongchun Qiao Guosheng Pu Masaru Ichikawa
Ludovico MINATI
Minoru Fujishima
Hyunuk AHN Akito IGUCHI Keita MORIMOTO Yasuhide TSUJI
Kensei ITAYA Ryosuke OZAKI Tsuneki YAMASAKI
Akira KAWAHARA Jun SHIBAYAMA Kazuhiro FUJITA Junji YAMAUCHI Hisamatsu NAKANO
Seiya Kishimoto Ryoya Ogino Kenta Arase Shinichiro Ohnuki
Yasuo OHTERA
Tomohiro Kumaki Akihiko Hirata Tubasa Saijo Yuma Kawamoto Tadao Nagatsuma Osamu Kagaya
Haonan CHEN Akito IGUCHI Yasuhide TSUJI
Keiji GOTO Toru KAWANO Munetoshi IWAKIRI Tsubasa KAWAKAMI Kazuki NAKAZAWA
Yohtaro UMEDA Takatomo ENOKI Kunihiro ARAI Yasunobu ISHII
Noise characteristics of InAlAs/InGaAs HEMT's passivated by SiN are investigated to ascertain their suitability for practical applications in circuit such as MMIC's. A 0.18-µm-gate-length device with 125-µm-gate width and 8-gate fingers showed the lowest minimum noise figure of 0.43 dB at 26 GHz with an associated gain of 8.5 dB of any passivated device ever reported. This value is also comparable to the lowest reported minimum noise figure obtained by bare InAlAs/InGaAs HEMT's in spite of increased parasitic capacitances due to the SiN passivation. Thes excellent noise performance was achieved by employing non-alloyed ohmic contact, a T-shaped gate geometry and a multi-finger gate pattern. To reduce the contact resistance of the non-alloyed ohmic contact, a novel n+-InGaAs/n+-InAlAs cap layer was used resulting in a very low contact resistance of 0.09 Ωmm and a low sheet resistance for all layers of 145 Ω/sq. No increase in these resistances was observed after SiN passivation, and a very low source resistance of 0.16 Ωmm was obtained. An analysis of equivalent circuit parameters revealed that the T-shaped gate and multi-finger gate pattern drastically decrease gate resistance.
Takashi YAMADA Masao NISHIDA Tetsuro SAWAI Yasoo HARADA
An integrated CAD/CAM system for MMIC development has been firstly realized, which consists of electron beam direct drawing, microwave circuit simulator, pattern generator and RF &DC on-wafer automatic measurement subsystems, connected through an Ethernet LAN. The system can develop not only new MMICs and their element devices, but also their accurate simulation models quickly and efficiently. Preliminary successful applications of this system have been demonstrated by DC-HFET with a 0.25 µm T-shaped gate electrode and MMIC low-noise amplifiers operating at X- and L-bands.
Kazuo NAGATOMO Shoichi KOIKE Naofumi OKUBO Masafumi SHIGAKI
This paper describes the design of a 38-GHz high power MMIC amplifier using an improved load-pull technique. We improved the load-pull technique accuracy by using MMIC transtormers to match the input and output impedances of a GaAs MESFET to about 50 ohms. We used this technique to measure the large-signal load impedance of a FET with a 600-µm-wide gate. Using the data obtained, we developed an MMIC amplifier composed of two of these FET cells. At 38 GHz, the amplifier has an output power of 23.5 dBm for a 1 dB gain compression level.
Tadashi TAKAGI Kiyoharu SEINO Takuo KASHIWA Tsutomu HASHIMOTO Fumio TAKEDA
A Ka-band 0.5 W monolithic amplifier using a novel tandem FET has been developed. The tandem FET consists of two FET cells connected in series through a short transmission line. The features of the tandem FET are high gain, flat gain response and miniaturized size. The tandem FET is very useful for obtaining high gain, high power amplifiers operating in millimeter-wave region where combining and matching circuits' losses are significantly large. By combining four tandem FETs, a linear gain of 4.5 dB, a 1 dB compressed power of 26.3 dBm and a saturated output power of 27.3 dBm (0.54 W) have been achieved at 37 GHz. The size of the amplifier is 1.7
An extremely accurate and very wide-band quadrature modulator IC fabricated on a single chip using bipolar technology is presented. The characteristics of this quadrature modulator IC are much superior to conventional ones (modulation phase error and deviation from quadrature is about 1/10), and this IC is applicable to high modulation schemes such as 256 QAM. In this circuit, the phase difference between local signals input to each of two balanced modulators is detected by a phase detector, and a variable phase shifter in the local port is controlled automatically by the detected signals. This, along with the use of a wide-band variable phase shifter, enables the phase difference between the local signals input to the balanced modulators to be adaptively controlled to 90 degrees in wide frequency bands. In addition, a design method for the balanced modulators to obtain small modulation phase error is described. Based on this design method, a highly accurate quadrature modulator IC was fabricated, in which two balanced modulators, the phase detector, and the variable phase shifter were integrated on a single chip. Phase deviation from quadrature in the local signals was reduced to less than
Nobuyuki HAYAMA Jun-ichi SHIMIZU Kazuhiko HONJO
Design consideration, fabrication process, and performance of a fully monolithic 22 GHz-band oscillator implemented using a self-aligned AlGaAs/GaAs heterojunction bipolar transistor (HBT) are described. For optimization of the oscillator circuit parameters, large-signal circuit model parameters extracted from bias dependent small-signal S-parameters have been used to maximumize an output power. The developed oscillator employs a 1.5
This paper proposes an MMIC image rejection mixer and an MMIC balanced mixer employing multilayer microstrip lines and high-electron-mobility-field-effect-transistor (HEMT)s with a LUFET configuration (line-unified HEMT module). The advantage of the mixers is remarkable chip size reduction by the combination of the two technologies. The multilayer microstrip line, in which one microstrip line is placed upon another, is used for stacking passive circuits, e.g. a 90
Tsuneo TOKUMITSU Takahiro HIRAOKA Hiroyuki NAKAMOTO Masayoshi AIKAWA
Novel, very small-size multilayer MMIC's using miniature microstrip lines on a thin dielectric film, as well as the features of the multilayer structure, are presented. Very narrow-width thin-film transmission lines, meander-like configurations, line crossovers, and vertical connections, which are effective for significant chip-size reduction and flexible layout, are realized and utilized in a 2.5-3 µm
Takao HASEGAWA Seiichi BANBA Hiroyo OGAWA Tsuneo TOKUMITSU
This paper describes multi-branch Wilkinson power dividers using multilayer MMIC technology. Circuit configuration is simplified and the circuit area is effectively minimized using thin film microstrip lines. An impedance transformer between the input port and the divided point is introduced to complete impedance matching and reduce insertion loss in multi-branch power dividers. Size-reduced planar-type 2-, 4-, and 8-branch Wilkinson power dividers are produced and performed well.
Seiichi BANBA Takao HASEGAWA Hiroyo OGAWA Tsuneo TOKUMITSU
Novel transmission line structures for multilayer MMICs, which are constructed with thin dielectric layers on a GaAs wafer surface, are theoretically and experimentally investigated. Five thin film transmission line structures are discussed in this paper: (1) Microstrip lines, (2) Inverted microstrip lines, (3) Triplate lines, (4) Trapezoidal microstrip lines and (5) Valley microstrip lines. These transmission line structures are fabricated using thin polyimide films and chemical etching.
This paper proposes three configurations of slow-wave transmission lines for MMICs, i.e., double crosstie slow-wave transmission line (DCT-SLW), meander-like DCT-SLW and lumped DCT-SLW. The DCT-SLW is based on periodic structures and triplate structures. The meander-like DCT-SLW realizes a drastic size reduction in the DCT-SLW using a meander configuration of inductive and capacitive transmission lines. The multilayer spiral inductors are introduced to obtain high impedance characteristics of the meander section. The lumped DCT-SLW achieves a large slow-wave factor of 30. These proposed structures are analytically and experimentally investigated, and excellent performance is obtained. It is also shown that the proposed DCT-SLWs are superior to thin film microstrip (TFMS) lines with the same insertion phase, as regards size.
WANG Guo-Hua Kenzo WATANABE Yutaka FUKUI
A dual transformation incorporating the frequency-dependent scaling factor with the impedance dimension is proposed to synthesize the current-mode counterpart of a voltage-mode original. A general class of current-mode active-RC biquadratic filters and a switched-capacitor low-pass biquad are derived to demonstrate the synthesis procedure. Their simulation and test results show that the current transfer functions are the same as the voltage transfer functions of the originals, and thus confirm the validity of the procedure. The dual trasformation described herein is general in that with the scaling factor chosen appropriately it can meet a wide variety of circuit transformation, and thus useful also for circuit classification and identification.
Akihiro MARUTA Masanori MATSUHARA
A simple method is developed to analyze a bent waveguide, which is described in the cylindrical coordinate system. By means of this method based on the Galerkin method, the sampling spacing can be chosen arbitrarily and it is possible to treat narrow beams. In addition we introduce the absorber using the graded lossy material. As this lossy absorber can remove the radiation wave from the bend, so we can use the finite computational window. The lightwaves propagating in the uniform bend of the slab waveguide and of the nonlinear slab waveguide are demonstrated.
Fumihiko ITO Ken-ichi KITAYAMA
Fourier holographic image storage and reconstruction using BaTiO3 photorefractive crystal waveguide is investigated. The phase conjugation technique, which compensates image distortion caused by modal phase dispersion, successfully retores images stored in a test BaTiO3 crystal waveguide.
The selection method of the moment of inertia of the flywheel in a digital measurement system of torque-speed curve plotting for a kind of motor is presented. The selection standards of the moment of inertia and the map displaying the operating ranges of the measurement system are shown. The selection procedure of the moment of inertia is also shown.