Ken HIRAGA

Orbital Angular Momentum (OAM) Multiplexing: An Enabler of a New Era of Wireless Communications
Doohwan LEE Hirofumi SASAKI Hiroyuki FUKUMOTO Ken HIRAGA Tadao NAKAGAWA 
Publication:   
Publication Date: 2017/07/01
Vol. E100-B  No. 7  pp. 1044-1063
Type of Manuscript:  INVITED PAPER (Special Section on Smart Radio and Its Applications in Conjunction with Main Topics of SmartCom)
Category: Transmission Systems and Transmission Equipment for Communications
Keyword: 
orbital angular momentum multiplexing, uniform circular array, Gaussian beam, Bessel beam, lens antenna, 
 Summary | Full Text:PDF
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: 
MIMO, directivity, spatial division, channel 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: 
MIMO, directivity, higher order mode, capacity, 
 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 transmission, array a ntennas, parallel transmission, line-of-sight (LOS), two-ray ground reflection model, reflection coefficient, polarization, 
 Summary | Full Text:PDF
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 transmission, zero forcing, unitary matrix, 90-degree phase shifter, optimal 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-range, MIMO, polarization multiplexing, XPD, antennas, decoding, 
 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 MIMO, controlling phase difference, power ratio, sub-array antenna, millimeter-wave, simple 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 MIMO, dual-polarization, array antennas, parallel transmission, high-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-range, MIMO, millimeter-wave, antennas, parallel transmission, 
 Summary | Full Text:PDF