Tadao NAKAGAWA


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 multiplexinguniform circular arrayGaussian beamBessel beamlens antenna
 Summary | Full Text:PDF

Throughput Enhancement for SATCOM Systems Using Dynamic Spectrum Controlled Channel Allocation under Variable Propagation Conditions
Katsuya NAKAHIRA Jun MASHINO Jun-ichi ABE Daisuke MURAYAMA Tadao NAKAGAWA Takatoshi SUGIYAMA 
Publication:   
Publication Date: 2017/02/01
Vol. E100-B  No. 2  pp. 390-399
Type of Manuscript:  PAPER
Category: Satellite Communications
Keyword: 
satellite communicationchannel allocationresource controladaptive coding and modulationspectrum compressionspectrum divisiondemand assigned multiple access
 Summary | Full Text:PDF

Wide-Range and Fast-Tracking Non-Data-Aided Frequency Offset Estimator for QAM Optical Coherent Receivers
Tadao NAKAGAWA Takayuki KOBAYASHI Koichi ISHIHARA Yutaka MIYAMOTO 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2016/07/01
Vol. E99-B  No. 7  pp. 1416-1425
Type of Manuscript:  PAPER
Category: Fiber-Optic Transmission for Communications
Keyword: 
optical fiber communicationoptical receiversquadrature amplitude modulationdigital signal processingfrequency offset estimation
 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: 
MIMOdirectivityspatial divisionchannel capacity
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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

Concurrent Multi-Band Mixer with Independent and Linear Gain Control
Takana KAHO Yo YAMAGUCHI Hiroyuki SHIBA Tadao NAKAGAWA Kazuhiro UEHARA Kiyomichi ARAKI 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 2015/07/01
Vol. E98-C  No. 7  pp. 659-668
Type of Manuscript:  Special Section PAPER (Special Section on Microwave and Millimeter-Wave Technology)
Category: Active Circuits/Devices/Monolithic Microwave Integrated Circuits
Keyword: 
concurrent multi-band mixerdual-bandtriple-bandSiGe BiCMOSflexible wireless system
 Summary | Full Text:PDF

Experimental Validation of Digital Pre-distortion Technique for Dual-band Dual-signal Amplification by Single Feedback Architecture Employing Dual-band Mixer
Ikuma ANDO Gia Khanh TRAN Kiyomichi ARAKI Takayuki YAMADA Takana KAHO Yo YAMAGUCHI Tadao NAKAGAWA 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 2015/03/01
Vol. E98-C  No. 3  pp. 242-251
Type of Manuscript:  PAPER
Category: Electromagnetic Theory
Keyword: 
User Centric Wireless Networknonlinear power amplifiersspectral regrowthdigital predistortiondual-band mixer
 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
 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

A Band-Divided Receiver Prototype for Wideband Optical Signals
Munehiro MATSUI Riichi KUDO Yasushi TAKATORI Tadao NAKAGAWA Koichi ISHIHARA Masato MIZOGUCHI Takayuki KOBAYASHI Yutaka MIYAMOTO 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2011/07/01
Vol. E94-B  No. 7  pp. 1801-1808
Type of Manuscript:  Special Section PAPER (Joint Special Section on Opto-electronics and Communications for Future Optical Network)
Category: 
Keyword: 
coherent receiveranalog to digital converterOFDMreal-timeheterodyne receiver
 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

A Miniaturized In-Phase Power Divider with a DC Block Function
Hitoshi HAYASHI Tadao NAKAGAWA Kazuhiro UEHARA Yoshihiro TAKIGAWA 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 2007/10/01
Vol. E90-C  No. 10  pp. 2022-2029
Type of Manuscript:  PAPER
Category: Microwaves, Millimeter-Waves
Keyword: 
in-phasepowerdividerminiaturizedDC block
 Summary | Full Text:PDF

Miniaturized Broadband Lumped-Element In-Phase Power Dividers
Hitoshi HAYASHI Tadao NAKAGAWA Kazuhiro UEHARA Yoshihiro TAKIGAWA 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 2007/06/01
Vol. E90-C  No. 6  pp. 1222-1227
Type of Manuscript:  Special Section PAPER (Special Section on Analog Circuits and Related SoC Integration Technologies)
Category: 
Keyword: 
in-phasepowerdividerminiaturizedlumped-elementbroadband
 Summary | Full Text:PDF

An Active Terminal Circuit and Its Application to a Distributed Amplifier
Hitoshi HAYASHI Munenari KAWASHIMA Tadao NAKAGAWA Kazuhiro UEHARA Yoshihiro TAKIGAWA 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 2007/06/01
Vol. E90-C  No. 6  pp. 1203-1208
Type of Manuscript:  Special Section PAPER (Special Section on Analog Circuits and Related SoC Integration Technologies)
Category: 
Keyword: 
distributedamplifiercascode-connectedDarlington pair
 Summary | Full Text:PDF

A Novel Adaptive Linearization Technique for a Balanced-Amplifier Array
Takana KAHO Yo YAMAGUCHI Tadao NAKAGAWA Katsuhiko ARAKI Kiyomichi ARAKI 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 2006/10/01
Vol. E89-C  No. 10  pp. 1448-1453
Type of Manuscript:  PAPER
Category: Microwaves, Millimeter-Waves
Keyword: 
adaptive linearizationlinearizermulti-port amplifierpower amplifiersarray antenna
 Summary | Full Text:PDF

A Monolithic Linearizer Using an Even-Order-Distortion Controller for an S-Band High Power Amplifier
Takana KAHO Hiroshi OKAZAKI Tadao NAKAGAWA Katsuhiko ARAKI Kohji HORIKAWA 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 2002/12/01
Vol. E85-C  No. 12  pp. 1959-1966
Type of Manuscript:  Special Section PAPER (Special Issue on Low-Distortion,High-Power,High-Efficiency Active Device and Circuit Technology)
Category: 
Keyword: 
linearizeramplifierGaAs MMICsatellite communication
 Summary | Full Text:PDF

A 0.9-2.6 GHz Broadband RF Front-End Chip-Set with a Direct Conversion Architecture
Munenari KAWASHIMA Tadao NAKAGAWA Hitoshi HAYASHI Kenjiro NISHIKAWA Katsuhiko ARAKI 
Publication:   IEICE TRANSACTIONS on Communications
Publication Date: 2002/12/01
Vol. E85-B  No. 12  pp. 2732-2740
Type of Manuscript:  Special Section PAPER (Special Issue on Software Defined Radio Technology and Its Applications)
Category: 
Keyword: 
RF front-enddirect conversion architecturequadrature mixerlocal oscillatorlow-noise variable gain amplifier
 Summary | Full Text:PDF

A Phase Interpolation Direct Digital Synthesizer with a Symmetrically Structured Delay Generator
Hideyuki NOSAKA Tadao NAKAGAWA Akihiro YAMAGISHI 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 1999/07/25
Vol. E82-C  No. 7  pp. 1067-1072
Type of Manuscript:  Special Section PAPER (Special Issue on Microwave and Millimeter Wave Technology)
Category: Active Devices and Circuits
Keyword: 
direct digital synthesizerfrequency synthesizerdelay generatorspread spectrumjitter elimination
 Summary | Full Text:PDF

A Fast Frequency Switching Synthesizer with a Digitally Controlled Delay Generator
Hideyuki NOSAKA Tadao NAKAGAWA Akihiro YAMAGISHI 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1998/07/25
Vol. E81-A  No. 7  pp. 1466-1472
Type of Manuscript:  Special Section PAPER (Special Section on Fundamentals of Multi-dimensional Mobile Information Network)
Category: 
Keyword: 
direct digital synthesizerfrequency synthesizerlow powerspread spectrumfrequency hoppingspurious signals
 Summary | Full Text:PDF

A High-Efficiency Linear Power Amplifier with a Novel Output Power Control Technique
Yo YAMAGUCHI Masahiro MURAGUCHI Tadao NAKAGAWA Masashi NAKATSUGAWA 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 1998/06/25
Vol. E81-C  No. 6  pp. 892-897
Type of Manuscript:  Special Section PAPER (Special Issue on Microwave and Millimeter-Wave Module Technology)
Category: Semiconductor Devices and Amplifiers
Keyword: 
high efficiencylinearoutput power controlpower amplifiermobile communication
 Summary | Full Text:PDF

A Novel Optical Control Technique Using Tunable Inductance Circuits
Hitoshi HAYASHI Masashi NAKATSUGAWA Tadao NAKAGAWA Masahiro MURAGUCHI 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 1998/02/25
Vol. E81-C  No. 2  pp. 299-304
Type of Manuscript:  PAPER
Category: Microwave and Millimeter Wave Technology
Keyword: 
opticalcontroltunableinductancecircuit
 Summary | Full Text:PDF

A 2.7-V Quasi-Microwave Si-Bipolar Quadrature Modulator without Tuning
Tsuneo TSUKAHARA Tadao NAKAGAWA Masahiro MURAGUCHI 
Publication:   IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
Publication Date: 1997/02/25
Vol. E80-A  No. 2  pp. 349-352
Type of Manuscript:  Special Section LETTER (Special Section on Analog Circuit Techniques for System-on-Chip Integration)
Category: 
Keyword: 
Si bipolarquadrature modulatorquasi-microwavedigital mobile communication
 Summary | Full Text:PDF

Low-Noise MMIC Phase-Locked Oscillators Using an EXOR and a PFC
Tadao NAKAGAWA Hideo SUWAKI Takashi OHIRA 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 1993/06/25
Vol. E76-C  No. 6  pp. 950-954
Type of Manuscript:  Special Section PAPER (Special Issue on Microwave and Millimeter-Wave Technology for Advanced Functions and Size-Reductions)
Category: 
Keyword: 
phase noiseMMICPLOPFCEXOR
 Summary | Full Text:PDF

A GaAs Monolithic Sampling Phase Frequency Comparator for Extending the Pull-In Range of Microwave Phase-Locked Oscillators
Tadao NAKAGAWA Tetsuo HIROTA Takashi OHIRA 
Publication:   IEICE TRANSACTIONS on Electronics
Publication Date: 1993/06/25
Vol. E76-C  No. 6  pp. 944-949
Type of Manuscript:  Special Section PAPER (Special Issue on Microwave and Millimeter-Wave Technology for Advanced Functions and Size-Reductions)
Category: 
Keyword: 
samplingphase frequency comparatorMMICKu-bandpull-in range
 Summary | Full Text:PDF