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FOREWORD

Takana KAHO
2021 IEICE transactions on electronics  
Takana Kaho (Shonan Institute of Technology), Guest Editor-in-Chief Takana Kaho (Senior Member) received the B.S. and M.S. degrees in physics from Tokyo Metropolitan University, Japan, in 1994 and 1996  ... 
doi:10.1587/transele.2021mmf0001 fatcat:assqtdvirnaclitw2jctbjlhra

NTT研究所における子供科学教室

Takana Kaho, Hideyuki Mizuno
2014 IEICE Communications Society Magazine  
加保貴奈 Takana Kaho 日本電信電話 (株) NTT 未来ねっと研究所 水野秀之 Hideyuki Mizuno 日本電信電話 (株) NTT メディアインテリジェンス研究所 1 はじめに 2013 年 7 月 20 日 (土) に NTT 横須賀研究開発センタ 一般公開と電子情報通信学会東京支部と共同で子供向け の科学教室を行った.当教室は 2010 年から地域の小中 学生向  ... 
doi:10.1587/bplus.7.303 fatcat:3gwcii3ml5cqxoujtqtk2pe3ry

Improved gain 60 GHz CMOS antenna with N-well grid

Adel Barakat, Ahmed Allam, Hala Elsadek, Adel B. Abdel-Rahman, Ramesh K. Pokharel, Takana Kaho
2016 IEICE Electronics Express  
This paper presents a novel technique to enhance Antenna-on-Chip gain by introducing a high resistivity layer below it. Instead of using the costly ion implantation method to increase resistivity, the N-well that is available in the standard CMOS process is used. A distributed grid structure of N-well on P-type substrate is designed such that the P and N semiconductors types are fully depleted forming a layer with high resistivity. By an electromagnetic simulation, the using depletion layers
more » ... ance the antenna gain and radiation efficiency without increasing the occupied area. The simulated and measured |S11| are in fair agreement. The measured gain is −1.5 dBi at 66 GHz.
doi:10.1587/elex.13.20151115 fatcat:bqn7leplorgxhhxb4feen3jir4

A 12 to 24 GHz high efficiency fully integrated 0.18 µm CMOS power amplifier

Hamed Mosalam, Ahmed Allam, Hongting Jia, Adel Abdelrahman, Takana Kaho, Ramesh Pokharel
2016 IEICE Electronics Express  
This letter presents a high efficiency, and small group delay variations 12-24 GHz fully-integrated CMOS power amplifier (PA) for quasi-millimeter wave applications. Maximizing the power added efficiency (PAE), and minimizing the group delay variations in a wideband frequency range are achieved by optimizing the on-chip input, output, and inter-stage matching circuits. In addition, stagger tuning is employed for realizing excellent gain flatness. A two-stage CMOS PA using the proposed
more » ... y is designed and fabricated in 0.18 µm CMOS technology and tested. A measured power gain (|S 21 |) of 10.5 ± 0.7 dB and a measured small group delay variation of ±20 ps over the frequency range of interest are achieved. The PA shows a maximum measured PAE to be 26 % with DC power consumption of 50 mW.
doi:10.1587/elex.13.20160551 fatcat:uysd4mhf7jcfzdsjrw4eu5yoce

Nonlinear Modeling and Analysis on Concurrent Amplification of Dual-Band Gaussian Signals

Ikuma ANDO, GiaKhanh TRAN, Kiyomichi ARAKI, Takayuki YAMADA, Takana KAHO, Yo YAMAGUCHI, Kazuhiro UEHARA
2013 IEICE transactions on electronics  
In the recently developed Flexible Wireless System (FWS), the same platform needs to deal with different wireless systems. This increases nonlinear distortion in its wideband power amplifier (PA) because the PA needs to concurrently amplify multi-band signals. By taking higher harmonics as well as inter-and cross-modulation distortion into consideration, we have developed a method to analytically evaluate the adjacent channel leakage power ratio (ACPR) and error vector magnitude (EVM) on the
more » ... is of the PA's nonlinear characteristics. We devise a novel method for modeling the PA amplifying dual-band signals. The method makes it possible to model it merely by performing a one-tone test, making use of the Volterra series expansion and the general Wiener model. We then use the Mehler formula to derive the closed-form expressions of the PA's output power spectral density (PSD), ACPR, and EVM. The derivations are based on the assumption that the transmitted signals are complex Gaussian distributed in orthogonal frequency division multiplexing (OFDM) transmission systems. We validate the method by comparing measurement and simulation results and confirm it can appropriately predict the ACPR and EVM performance of the nonlinear PA output with OFDM inputs. In short, the method enables correct modeling of a wideband PA that amplifies dualband signals merely by conducting a one-tone test.
doi:10.1587/transele.e96.c.1254 fatcat:bj66lhhf35e7pjytyuncpqnqke

Reduction of Heat Generation from Onboard SSPA by Using Heat Suppression Signal
発熱抑制信号による衛星搭載用中継器の発熱低減評価

Akihiro Miyasaka, Takana Kaho, Jin Mitsugi, Yoshinori Nakasuga, Masazumi Ueba
2004 JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES  
Satellite communication systems have entered into the mobile multimedia communication era. To support small earth terminals, the satellites must have high levels of effective isotropic radiated power. Onboard high-power amplifiers are not only needed to generate high RF output power, but also to generate as less heat as possible. To address this issue, we present a new technique reducing an amount of heat generated in high power amplifiers on a satellite. The technique makes use of heat
more » ... ion signals so as to maintain the amplifier's power efficiency. The dissipation heat has been conventionally evaluated by consumption power of loaded FETs. However, the validity of this method has not yet been clarified on an experimental basis. Therefore, the dissipation heat from SSPAs was evaluated by other measurement technique, that is, we measured temperatures of SSPA and of air cooling. Furthermore, an effect of heat suppression was demonstrated.
doi:10.2322/jjsass.52.507 fatcat:iwpmi2cfpbbcdl7iro3tzqsfkm

FOREWORD

Shoichi NARAHASHI
2014 IEICE transactions on electronics  
.), Kazufumi Igarashi (Japan Radio), Takana Kaho (NTT), Masayuki Kimishima (ADVANTEST), Zhewang Ma (Saitama Univ.), Kenjiro Nishikawa (Kagoshima Univ.), Kensuke Okubo (Okayama Pref.  ... 
doi:10.1587/transele.e97.c.922 fatcat:rtin27afwbcxfafpyfegwqercq

FOREWORD

Naoki SHINOHARA
2018 IEICE transactions on electronics  
.), Ryo Ishikawa (The Univ. of Electro-Communications), Takana Kaho (NTT), Kazuhiro Iyomasa (Mitsubishi Electric), Zhewang Ma (Saitama Univ.), Masaya Tamura (Toyohashi Univ. of Tech.), Hiroyuki Kayano  ... 
doi:10.1587/transele.e101.c.718 fatcat:g5eo7cpqubabtcopjvtz64qwz4

Acknowledgments to Referees

2019 TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES AEROSPACE TECHNOLOGY JAPAN  
TAKANA Atsushi TAKANO Yoshihisa TAKAYAMA Shin-ichi TAKEDA Yoshiaki TAKEUCHI Mitsuaki TANABE Hiroaki TANAKA Hiroumi TANI Gordan Ray THIEDE Nobuyuki TSUBOI Takeshi TSUCHIYA Taro TSUKAMOTO  ...  Toshiyuki SUZUKI Yoichi SUZUKI Halil Ersin SÖKEN Hirokazu TAHARA Atsushi TAKADA Hideyuki TAKAHASHI Kenichi TAKAHASHI Masaya TAKAHASHI Masayuki TAKAHASHI Shun TAKAHASHI Yusuke TAKAHASHI Kaho  ... 
doi:10.2322/tastj.17.611 fatcat:srtxwl7j6ve55gsqjyamluujgq

Tietoa vahvistamassa ja saatavuutta parantamassa – NordILL 2021 -konferenssin satoa

Maarit Cederberg, Tuula Hurskainen, Sirpa Janhonen, Elisa Mörsky, Eija Kajava, Juha Leppämäki, Annamari Leppäniemi
2022 Signum  
Elina Kähö ja Juha Leppämäki esittelivät Helsingin yliopiston kirjaston Alma-kehittämishanketta.  ...  Sopimuksissa on myös ehtona välitön avoin julkaisu ilman, että aineistoa ensin pidetään maksumuurin takana.  ... 
doi:10.25033/sig.113615 fatcat:4qxake5o55f65eawcunujfxbs4