Etsuji Ogawa
Toshiba
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Featured researches published by Etsuji Ogawa.
international solid-state circuits conference | 2008
Tamio Ikehashi; Takayuki Miyazaki; Hiroaki Yamazaki; Atsushi Suzuki; Etsuji Ogawa; Shinji Miyano; Tomohiro Saito; Tatsuya Ohguro; Takeshi Miyagi; Yoshiaki Sugizaki; Nobuaki Otsuka; Hideki Shibata; Y. Toyoshima
We propose an IBA scheme based on a pull-out detection, which is suitable for implementing in a circuit. The scheme is implemented in a driver IC that is part of a module with an RF MEMS variable capacitor. No failures are observed over 108 cycles at 85degC, which is an accelerated charging condition.
international microwave symposium | 2010
Hiroaki Yamazaki; Tamio Ikehashi; Tomohiro Saito; Etsuji Ogawa; Takayuki Masunaga; Tatsuya Ohguro; Yoshiaki Sugizaki; Hideki Shibata
This paper presents an RF MEMS tunable capacitor that achieves an excellent power-handling property with relatively low actuation voltage. The tunable capacitor consists of two fixed MIM (Metal-Insulator-Metal) capacitors and two MEMS capacitor elements, all connected in series. This quadruple series capacitor (QSC) structure enables reduction of the actuation voltage without sacrificing the power-handling capability, since the MIM capacitor reduces the RF voltage amplitude applied to the MEMS capacitors. The measured result demonstrates +36dBm hot-switching at 85°C with 21V pull-in voltage.
international microwave symposium | 2006
Tamio Ikehashi; Tatsuya Ohguro; Etsuji Ogawa; Hiroaki Yamazaki; Kenji Kojima; Mie Matsuo; K. Ishimaru; H. Ishiuchi
An RF MEMS variable capacitor using hybrid actuation of piezoelectric and electrostatic forces is presented. A surface micromachining process is used to fabricate the device. The piezoelectric actuator, which uses thin film PZT, enables low voltage actuation while the electrostatic actuator realizes large capacitance ratio. The measured capacitance ratio is Cmax/Cmin=14 at 5V. We demonstrate that the hybrid actuation enables to lower the pull-in voltage without changing the pull-out voltage. We also show that the shift of pull-out voltage due to dielectric charging can be reduced drastically at actuation voltages below 10V. In this sense, the hybrid actuation can realize low voltage operation with enhanced robustness for stiction
asian solid state circuits conference | 2009
Yukako Tsutsumi; Masaki Nishio; Shuichi Obayashi; Hiroki Shoki; Tamio Ikehashi; Hiroaki Yamazaki; Etsuji Ogawa; Tomohiro Saito; Tatsuya Ohguro; Tasuku Morooka
It is difficult to realize the built-in antenna for wideband systems, because a frequency bandwidth of the low profile antenna is narrow. A frequency tunable antenna is a technique for wideband characteristics. In this paper a low profile double resonance frequency tunable antenna using MEMS variable capacitors is presented. It has high efficiency over a wide frequency band. Through both resonant portions from 465 to 665 MHz, the efficiency of more than −4 dB and the VSWR of less than 3 are observed in the measurement using the variable capacitor of 0.4–0.9 pF.
TRANSDUCERS 2009 - 2009 International Solid-State Sensors, Actuators and Microsystems Conference | 2009
Akihiro Kojima; Yoshiaki Shimooka; Yoshiaki Sugizaki; Mitsuyoshi Endo; Hiroaki Yamazaki; Etsuji Ogawa; Tamio Ikehashi; Tatsuya Ohguro; Susumu Obata; Takeshi Miyagi; Ikuo Mori; Y. Toyoshima; Hideki Shibata
In this paper, we report a thin-film encapsulation technology for wafer-level micro-electro-mechanical systems (MEMS) variable capacitor package. The electrical characteristics of MEMS are adversely affected by moisture. In order to prevent moisture from permeating into a package, the top surface was protected with a plasma-enhanced chemical vapor deposition (PE-CVD) SiN layer. The developed packages become a hybrid thin-film hermetic encapsulation consisting of an internal shell using PE-CVD SiO, a seal layer coating with resin, and an external protective layer formed by PE-CVD SiN. The process is fully compatible with standard low-cost back-end-of-the-line (BEOL) technologies for LSIs as a wafer-level package (WLP). This hybrid structure was very effective for protecting the MEMS device from external moisture. Moreover, the electrode surface area has to be wide, because a wide range of capacities is necessary in MEMS variable capacitors. We have developed a large (1480 × 1080 µm) hermetic thin-film encapsulation as WLP.
electronic components and technology conference | 2012
Yoshihiko Kurui; Hiroaki Yamazaki; Yoshiaki Shimooka; Tomohiro Saito; Etsuji Ogawa; T. Ogawa; Tamio Ikehashi; Yoshiaki Sugizaki; Hideki Shibata
This paper reports on 1-chip RF-MEMS tunable capacitor that equips CMOS driver circuit in the underlying layer. A Wafer Level Chip Scale Package (WLCSP) optimized for RF-MEMS is employed to minimize the module size. The MEMS actuation voltage is generated by an Actuation Voltage Generator (AVG). The boost mechanism employed in the AVG enables instant high voltage generation and reduction of the dielectric charging. The measured noise at RF frequencies is less than -120dbm, thanks to a shield metal layer formed between MEMS and CMOS layers. To achieve high power handing and high creep immunity, we employ the previously reported techniques, the Quadruple Series Capacitor (QSC) [1] and the SiN springs [2]. The quality factor measured in the WLCSP is larger than 100 at 1GHz. The capacitance can be changed from 1.4pF to 5pF by a step of 0.45pF.
2017 IEEE International Symposium on Inertial Sensors and Systems (INERTIAL) | 2017
Ryunosuke Gando; Haruka Kubo; Kei Masunishi; Yasushi Tomizawa; Etsuji Ogawa; Shunta Maeda; Yohei Hatakeyama; Tetsuro Itakura; Tamio Ikehashi
This paper presents a novel MEMS gyroscope that employs intermittent free vibration and mode matching. An intermittent operation is realized by a “Catch-and-Release (CR)” technique, which enables significant reduction of the drive power. Sensitivities of the mode-matching and mode-split conditions are investigated by electrostatically tuning the sense-mode frequency. A sensitivity as high as 2.14 mV/dps, 52 times higher than the mode-split case, is obtained when the drive and sense frequency difference Δƒ is reduced to 50 Hz. Optimization for mode matching and quadrature nulling is also demonstrated.
TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference | 2007
Tamio Ikehashi; Etsuji Ogawa; Hiroaki Yamazaki; Tatsuya Ohguro
A 3 V operation RF MEMS variable capacitor using hybrid actuation of piezoelectric and electrostatic forces is presented. Bending of the piezoelectric actuator is controlled by a lithographical pattern formed on top of the actuator. The hybrid actuation and the optimized bending enabled 2.6 V pull- in voltage with the pull-out voltage as high as 2.0 V The measured capacitance ratio is 14.
Sensors and Actuators A-physical | 2007
Hiroaki Yamazaki; Tamio Ikehashi; Tatsuya Ohguro; Etsuji Ogawa; Kenji Kojima; K. Ishimaru; H. Ishiuchi
Sensors and Actuators A-physical | 2011
Etsuji Ogawa; Tamio Ikehashi; Tomohiro Saito; Hiroaki Yamazaki; Kei Masunishi; Yasushi Tomizawa; Tatsuya Ohguro; Yoshiaki Sugizaki; Y. Toyoshima; Hideki Shibata