Tomohiro SEKI


Alignment Tolerance in Multiple-Stream Transmission Using Orthogonal Directivities under Line-of-Sight Environments
Maki ARAI Tomohiro SEKI Ken HIRAGA Kazumitsu SAKAMOTO Tadao NAKAGAWA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2016/06/01
Vol. E99-B  No. 6  pp. 1362-1370
Type of Manuscript:  PAPER
Category: Antennas and Propagation
Keyword: 
MIMOdirectivityspatial divisionchannel capacity
 Summary | Full Text:PDF

Orthogonalized Directional MIMO Transmission Using Higher Order Mode Microstrip Antennas
Maki ARAI Tomohiro SEKI Ken HIRAGA Kazumitsu SAKAMOTO Hideki TOSHINAGA Tadao NAKAGAWA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2016/01/01
Vol. E99-B  No. 1  pp. 48-57
Type of Manuscript:  Special Section PAPER (Special Section on Recent Progress in Antennas, Propagation and Wireless Systems Related to Topics in ISAP2014)
Category: Antennas and Propagation
Keyword: 
MIMOdirectivityhigher order modecapacity
 Summary | Full Text:PDF

Spatial Division Transmission without Signal Processing for MIMO Detection Utilizing Two-Ray Fading
Ken HIRAGA Kazumitsu SAKAMOTO Maki ARAI Tomohiro SEKI Tadao NAKAGAWA Kazuhiro UEHARA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2014/11/01
Vol. E97-B  No. 11  pp. 2491-2501
Type of Manuscript:  PAPER
Category: Wireless Communication Technologies
Keyword: 
spatial division transmissionarray a ntennasparallel transmissionline-of-sight (LOS)two-ray ground reflection modelreflection coefficientpolarization
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Multiband Sector Antenna with the Same Beamwidth Employing Multiple Woodpile Metamaterial Reflectors
Hideya SO Atsuya ANDO Tomohiro SEKI Munenari KAWASHIMA Takatoshi SUGIYAMA 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 2014/10/01
Vol. E97-C  No. 10  pp. 976-985
Type of Manuscript:  Special Section PAPER (Special Section on Recent Progress in Microwave and Millimeter-wave Technologies)
Category: 
Keyword: 
sector base station antennamultiband antennametamaterialelectromagnetic band gap (EBG) characteristics
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Analog Decoding Method for Simplified Short-Range MIMO Transmission
Ryochi KATAOKA Kentaro NISHIMORI Takefumi HIRAGURI Naoki HONMA Tomohiro SEKI Ken HIRAGA Hideo MAKINO 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2014/03/01
Vol. E97-B  No. 3  pp. 620-630
Type of Manuscript:  PAPER
Category: Antennas and Propagation
Keyword: 
short-range MIMO transmissionzero forcingunitary matrix90-degree phase shifteroptimal element spacing
 Summary | Full Text:PDF

A Study of Short-Range MIMO Transmission Utilizing Polarization Multiplexing for the Simplification of Decoding
Ken HIRAGA Kazumitsu SAKAMOTO Kentaro NISHIMORI Tomohiro SEKI Tadao NAKAGAWA Kazuhiro UEHARA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2014/02/01
Vol. E97-B  No. 2  pp. 459-468
Type of Manuscript:  PAPER
Category: Antennas and Propagation
Keyword: 
short-rangeMIMOpolarization multiplexingXPDantennasdecoding
 Summary | Full Text:PDF

Performance Evaluation of Short-Range MIMO Using a Method for Controlling Phase Difference between Each Propagation Channel
Kazumitsu SAKAMOTO Ken HIRAGA Tomohiro SEKI Tadao NAKAGAWA Kazuhiro UEHARA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2013/10/01
Vol. E96-B  No. 10  pp. 2513-2520
Type of Manuscript:  Special Section PAPER (Special Section on Recent Progress in Antennas and Propagation in Conjunction with Main Topics of ISAP2012)
Category: Adaptive Array Antennas/MIMO
Keyword: 
short-range MIMOcontrolling phase differencepower ratiosub-array antennamillimeter-wavesimple decoding method
 Summary | Full Text:PDF

Effectiveness of Short-Range MIMO Using Dual-Polarized Antenna
Ken HIRAGA Tomohiro SEKI Kentaro NISHIMORI Kazuhiro UEHARA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2012/01/01
Vol. E95-B  No. 1  pp. 87-96
Type of Manuscript:  Special Section PAPER (Special Section on Recent Progress in Antennas and Propagation in Conjunction with Main Topics of ISAP2010)
Category: Radio Systems
Keyword: 
short-range MIMOdual-polarizationarray antennasparallel transmissionhigh-speed transmission
 Summary | Full Text:PDF

Analyses of Antenna Displacement in Short-Range MIMO Transmission over Millimeter-Wave
Ken HIRAGA Tomohiro SEKI Kentaro NISHIMORI Kenjiro NISHIKAWA Ichihiko TOYODA Kazuhiro UEHARA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2011/10/01
Vol. E94-B  No. 10  pp. 2891-2895
Type of Manuscript:  LETTER
Category: Antennas and Propagation
Keyword: 
short-rangeMIMOmillimeter-waveantennasparallel transmission
 Summary | Full Text:PDF

An Analysis of Multi-Layer Inductors for Miniaturizing of GaAs MMIC
Yo YAMAGUCHI Takana KAHO Motoharu SASAKI Kenjiro NISHIKAWA Tomohiro SEKI Tadao NAKAGAWA Kazuhiro UEHARA Kiyomichi ARAKI 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 2010/07/01
Vol. E93-C  No. 7  pp. 1119-1125
Type of Manuscript:  Special Section PAPER (Special Section on Recent Progress in Microwave and Millimeter-Wave Technologies)
Category: 
Keyword: 
multi-layer inductorstacked inductorthree-dimensional MMICGaAs
 Summary | Full Text:PDF

Series-Fed Beam-Scanning Antenna Employing Multi-Stage Configured Microstrip Antennas with Tunable Reactance Devices
Naoki HONMA Tomohiro SEKI Kenjiro NISHIKAWA Koichi TSUNEKAWA Kunio SAWAYA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2005/06/01
Vol. E88-B  No. 6  pp. 2297-2304
Type of Manuscript:  Special Section PAPER (Special Section on 2004 International Symposium on Antennas and Propagation)
Category: 
Keyword: 
tunable reactance devicemicrostrip antennabeam scanningmulti-stagetraveling wave
 Summary | Full Text:PDF

25 GHz Band Active Integrated Antenna for Broadband Mobile Wireless Access Systems
Tomohiro SEKI Fusao NUNO Takeo ATSUGI Masahiro UMEHIRA Junji SATO Takashi ENOKI 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 2003/08/01
Vol. E86-C  No. 8  pp. 1520-1526
Type of Manuscript:  Special Section PAPER (Special Issue on Microwave and Millimeter Wave Technology)
Category: 
Keyword: 
active integrated antennaMSL/slot transitionspatial power combining schemesbroadband mobile wireless accessquasi-millimeter and millimeter-wave frequency band
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Cylindrical Multi-Sector Antenna with Self-Selecting Switching Circuit
Tomohiro SEKI Toshikazu HORI 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2001/09/01
Vol. E84-B  No. 9  pp. 2407-2412
Type of Manuscript:  Special Section PAPER (Special Issue on Innovation in Antennas and Propagation for Expanding Radio Systems)
Category: Millimeter-Wave Antennas
Keyword: 
high-speed wireless communicationsector antennaquasi-millimeter and millimeter-wave frequency bandcylindrical antenna
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Mobile Multimedia Satellite Communication System at Ku Band
Fumiaki NAGASE Hiroshi TANAKA Masayoshi NAKAYAMA Tomohiro SEKI Hiroshi KAZAMA Hideki MIZUNO 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2001/04/01
Vol. E84-B  No. 4  pp. 903-909
Type of Manuscript:  Special Section PAPER (Special Issue on Mobile Multimedia Communications)
Category: 
Keyword: 
satellite communicationmobile communicationmultimediatracking antennasystem throughput
 Summary | Full Text:PDF

30-GHz Multibeam Antenna Using Bi-Layer Butler Matrix Circuits
Tomohiro SEKI Kazuhiro UEHARA Kenichi KAGOSHIMA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 1996/12/25
Vol. E79-B  No. 12  pp. 1778-1783
Type of Manuscript:  Special Section PAPER (Special Issue on Millimeter-wave Short-range Application Systems Technology)
Category: 
Keyword: 
multibeam antennaButler matrixmillimeter-waveslot-coupled hybridbi-layer
 Summary | Full Text:PDF

A Planar Sector Antenna for Indoor High-Speed Wireless Communication Systems
Kazuhiro UEHARA Tomohiro SEKI Kenichi KAGOSHIMA 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 1996/12/25
Vol. E79-B  No. 12  pp. 1773-1777
Type of Manuscript:  Special Section PAPER (Special Issue on Millimeter-wave Short-range Application Systems Technology)
Category: 
Keyword: 
sector antennaphased arraymulti-beam antennamillimeter-wave communication
 Summary | Full Text:PDF