Masataka OHIRA, Dr.
Affiliation
 Associate Professor (April 2014  Present)
Graduate School of Science and Engineering, Saitama University  255 ShimoOhkubo, Sakuraku, Saitamashi, 3388570 JAPAN
 URL: http://sirius.reso.ees.saitamau.ac.jp/ohirame.html
Career
 Assistant Professor, Graduate School of Science and Engineering, Saitama University (April 2010  March 2014)
 Visiting Researcher, Advanced Telecommunication Research Institute International (ATR) (July 2011  March 2013)
 Visiting Researcher, Advanced Telecommunication Research Institute International (ATR) Wave Engineering Lab. (June 2010  March 2011)
 Researcher, Advanced Telecommunication Research Institute International (ATR) Wave Engineering Lab. (April 2006  March 2010)
Academic Background
 B. Eng., Department of Engineering, Doshisha University (April 1997  March 2001)
 M. Eng., Graduate School of Engineering, Doshisha University (April 2001  March 2003)
 D. Eng., Graduate School of Engineering, Doshisha University (April 2003  March 2006)
Academic Societies
 The Institute of Electronics, Information and Communication Engineers (IEICE), Japan
 The Institute of Electrical Engineers of Japan
 IEEE (Microwave Theory and Technique Society (MTTS), Antenna and Propagation Society (APS))
 EuMA
Prizes
 IEICE Best Paper Award (2018)
 IEEE MTTS Japan Young Engineer Award (2014)
 Michiyuki Uenohara Memorial Award (2014)
 IEEE APS Japan Chapter Young Engineer Award (2012)
 CJMW2011 (ChinaJapan Microwave Conference) Microwave Prize (2011)
Research Areas
 Antenna theory, design, and measurements; filter theory, design and measurements; and other passive component designs.
 Research and development of microwave and millimeterwave filters
 Research and development of comact antennas, smart antennas, and millimeterwave antennas
 Electromagnetic analysis
Keywords
 Electromagnetic waves
 Filters, antennas & propagation
 High frequency, microwave, millimeterwave
 Electromagnetic analysis and design
 Electromagnetic circuit elements
Recent Research
(1) Fully Canonical Microwave Filter Designs
 Transversal coupling filters
 CuldeSac coupling filters
 Multimode filters
(2) Tunable/Reconfigurable Filter Designs
 Transfer function reconfigurable filters
 BPF/BSF switching filters
 Tunable filters
(3) Filtering Antenna Designs
 Microstrip filtering antenna designs
 Tunable filtering antenna designs
 Wideband filtering antenna designs
(4) Development of Automatic Passive Circuit Pattern Design Software
 Automatic pattern generation using neural network and optimization techniques
 Development of coupling matrix extraction techniques
 Development of filter tuning techniques
Research Career
ATR Wave Engineering Laboratories (Apr. 2006  Mar. 2010)
 Research and development of 60GHzband switched beam antenna for multigigabit highspeed wireless loca area network (LAN)
 Research and development of microwave smart antennas for an efficient spectrum use with space division multiplexing (SDM) technology in 2.4GHz and 5GHz wireless local area network
 Investigation on microwave radio propagation in ICT equipment for nextgeneration machinetomachine (M2M) wireless communications
 Research and development of submillimeterwave antennas for imaging technologies
 Research and development of antenna miniaturization for UVHF bands
Doshisha University (Apr. 2001  Mar. 2006)
 Analysis and design of multiband frequencyselective surfaces
 Analysis and design of FSSloaded waveguide filters
 Analysis and design of planar filters
 Analysis and design of horn antennas
 Electromagnetic analysis such as the method of moments and modematching methods
Frequency Selective Surfaces (FSS)
 "Multiband singllayer frequency selective surface designed by optimization technique," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, IEEJ Trans. on Fundamentals and Materials (Japanese Ed.), vol.123, no.3, pp.253258, Mar. 2003.
 "Multiband singlelayer frequency selective surface designed by combination of genetic algorithm and geometryrefinement technique," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, IEEE Trans. Antennas Propagat., vol.52, no.11, pp.29252931, Nov. 2004.
 "Analysis of frequency selective surface with arbitrarilyshaped element by equivalent circuit model," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, IEICE Trans. Electron. (Japanese Ed.), vol.J87C, No.12, pp.10301037, Dec. 2004.
 "Novel dualresonant and dualpolarized frequency selective surface using eightlegged element and its experimental verification," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, IEICE Trans. Electron., vol.E88C, no.12, pp.22292235, Dec. 2005.
Antennas and Propagation
 "Multiplestep rectangular horn with two orthogonal sectoral tapers for elliptical beam," H. Urata, M. Ohira, H. Deguchi, and M. Tsuji, IEICE Trans. Electron., vol.E90C, no.2, pp.217223, Jan. 2007.
 "60GHzband switchedbeam eightsector antenna with SP8T switch for 180Â° azimuth scan," A. Miura, M. Ohira, S. Kitazawa, and M. Ueba, IEICE Trans. Commun., vol.E93B, no.3, pp.551559, Mar. 2010.
 "60GHz wideband substrateintegratedwaveguide slot array using closely spaced elements for planar multisector antenna," M. Ohira, A. Miura, and M. Ueba, IEEE Trans. Antennas Propagat., vol.58, no.3, pp.993998, Mar. 2010.
 "Evolutionary generation of subwavelength planar element loaded monopole antenna," M. Ohira, H. Ban, and M. Ueba, IEEE Antennas and Wireless Propagat. Lett., vol.10, pp.15591562, Nov. 2011.
 "Experimental characterization of microwave radio propagation in ICT equipment for wireless harness communications," M. Ohira, T. Umaba, S. Kitazawa, H. Ban and M. Ueba, IEEE Trans. Antennas Propagat., vol.59, no.12, pp.47574765, Dec. 2011
 "Efficient gain optimization techniques for azimuth beam/null steering of invertedF multiport parasitic array radiator (MuPAR) antenna," M. Ohira, A. Miura, M. Taromaru, and M. Ueba, IEEE Trans. Antennas Propagat., vol.60, no.3, pp.13521361, Mar. 2012.
 “A new design formula of coupling coefficient between antenna and resonator for efficient design of filtering antenna,” M. Ohira, K. Yamanaka, and Z. Ma, IEICE Trans. Electron., vol.E99C, no.7, pp.744750, Jul. 2016.
 "Intraspacecraft wireless link and its application to spacecraft environmental tests," T. Toda, N. Kukutsu, S. Kitazawa, S. Ano, H. Kamoda, T. Kumagai, K. Kobayashi, M. Ohira, and S. Shimizu, Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan, vol.14, no.ists30, pp.2126, Feb. 2017.
Waveguide Filters
 "Novel waveguide filters with multiple attenuation poles using dualbehavior resonance of frequency selective surfaces," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, IEEE Trans. Microwave Theory Tech., vol.53, no.11, pp.33203326, Nov. 2005.
 "A novel waveguide bandpass filter with multiple attenuation poles using fourarmed squareloop FSSs," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, IEICE Trans. Electron. (Japanese Ed.), vol.J89C, no.7, pp.458465, July 2006.
 "Circuit synthesis for compact waveguide filters with closelyspaced frequency selective surfaces," M. Ohira, H. Deguchi, and M. Tsuji, International Journal of Microwave and Optical Technology, vol.1, no.2, pp.366370, Aug. 2006.
 "A new frequency selective window for constructing waveguide bandpass filters with multiple attenuation poles," M. Tsuji, H. Deguchi, and M. Ohira, Progress In Electromagnetics Research C, vol.20, pp.139153, 2011.
 "A novel feeding structure to generate multiple transmission zeros for miniature waveguide bandpass filters composed of frequencyselective surfaces," M. Ohira, Z. Ma, H. Deguchi, and M. Tsuji, IEICE Trans. Electron., vol.E94C, no.10, pp.15861593, Oct. 2011.
 “Improvement on stopband property of compact waveguide filters using hybrid resonances and antiresonances of cutoff waveguides and planar resonators,” T. Matsumoto, M. Ohira, and Z. Ma, IEICE Trans. on Electron. (Japanese Ed.), pp.524532, vol.J96C, no.12, Dec. 2013. (in Japanese)
Planar Filters
 "Planarcircuit bandpass filters consisting of arbitrarilyshaped elements," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, IEICE Trans. Electron. (Japanese Ed.), vol.J89C, no.5, pp.274281, May 2006.
 "Multiresonator generation by genetic optimization for application to planarcircuit bandpass filters," M. Tsuji, H. Deguchi, A. Kido, and M. Ohira, IEEJ Trans. on Fundamentals and Materials, vol.129, no.10, pp.681686, Oct. 2009.
 "Resonantmode characteristics of a new threemode hybrid microstrip/slotline resonator and novel realization of compact bandpass filter with four transmission zeros," M. Ohira and Z. Ma, IEICE Trans. Electron., vol.E95C, no.7, pp.12031210, Jul. 2012.
 "A parameterextraction method for microwave transversal resonator array bandpass filters with direct source/load coupling," M. Ohira and Z. Ma, IEEE Trans. Microwave Theory and Tech., vol.61, no.5, pp.18011811, May 2013.
 “A design method of multimode filters with transmission zeros using synthesis theory and parameter extraction technique for transversal array network,” H. Aoyama, M. Ohira, and Z. Ma, IEICE Trans. on Electron. (Japanese Ed.), pp.471479, vol.J96C, no.12, Dec. 2013. (in Japanese)
 “Authors' Reply,” M. Ohira and Z. Ma, IEEE Trans. Microwave Theory and Tech., vol.61, no.12, pp.42844285, Dec. 2013.
 “A compact threemode Hshaped resonator bandpass filter having high passband selectivity with four transmission zeros and wide stopband characteristic,” M. Ohira and Z. Ma, IEICE Trans. Electron., vol.E97C, no.10, pp.957964, Oct. 2014.
 "A fully canonical bandpass filter design using microstrip transversal resonator array configuration," M. Ohira, T. Kato, and Z. Ma, IEICE Trans. Electron., vol.E99C, no.10, pp.11221129, Oct. 2016.
 "Design of compact ultra wideband bandpass filters using shortcircuited stubs with improved stopband characteristics," R. Hamano, Z. Ma, and M. Ohira, IEICE Trans. Electron. (Japanese Ed.), vol.J99C, no.12, pp.618624, Dec 2016.
 "An improved couplingmatrix extraction method of microwave bandpass filters with deembedding technique for transmission loss of input/output lines," R. Tomita, M. Ohira, Z. Ma, and X. Wang, IEICE Trans. on Electron. (Japanese Ed.), vol.J100C, no.12, pp.569579, Dec. 2017.
 "A miniaturized dualband bandpass filter using composite resonators with flexible frequency ratio," P. Wen, Z. Ma, H. Liu, S. Zhu, B. Ren, X. Wang, and M. Ohira, IEICE Electronics Express, vol.15, no.5, pp.16, Feb. 2018.
 "Compact dualband differential bandpass filter using quadruplemode steppedimpedance square ring loaded resonators," B. Ren, H. Liu, Z. Ma, M. Ohira, P. Wen, X. Wang, X. Guan, IEEE Access, vol.6, pp.2185021858, Apr. 2018.
 "[Invited Paper] A tuningless design method of microwave bandpass filters using neural network based inverse model," A. Yamashita, Z. Ma, and M. Ohira, IEICE Trans. Electron. (Japanese Ed.), vol.J101C, no.8, pp.327335, Aug. 2018.
 "Balanced triband bandpass filter using sextmode steppedimpedance square ring loaded resonators," B. Ren, Z. Ma, H. Liu, X. Guan, P. Wen, C. Wang, and M. Ohira, IEICE Electronics Express, vol.15, no.18, p.2018670, Aug. 2018.
 "Compact dualband bandpass filter and diplexer using hybrid resonant structure with independently controllable dual passbands," B. Ren, H. Liu, Z. Ma, M. Ohira, X. Guan, P. Wen, and X. Wang, Int. Journal of RF and Microwave ComputerAided Eng., e21435, Sept. 2018.
 "Couplingmatrixbased systematic design of singleDCbiascontrolled microstrip higher order tunable bandpass filters with constant absolute bandwidth and transmission zeros," M. Ohira, S. Hashimoto, Z. Ma, and X. Wang, IEEE Trans. on Microwave Theory and Tech., Oct. 2018.
Other Passive Circuits
 "Study on equivalent circuit of coaxial line to postwall waveguide transition in 60GHz band," W. Luo, M. Ohira, A. Miura, and M. Ueba, Microw. Opt. Tech. Lett., vol.52, no.3, pp.623626, Jan. 2010.
 "Coupled microstrip line Wilkinson power divider with openstubs for compensation," X. Wang, M. Ohira, and Z. Ma, Electron. Lett., vol.52, no.15, pp.13141316, July 2016.
 "Accurate Schiffmantype section design approach for microstrip line Wilkinson power divider," X. Wang, M. Ohira, and Z. Ma, IEICE Electronics Express, July 2016.
 "Capacitive/Inductive compensation factor in coupled lines Wilkinson power divider design," X. Wang, M. Ohira, Z. Ma, I. Sakagami, A. Mase and M. Yoshikawa, Microw. Opt. Tech. Lett., vol.58, no.12, pp.29402944, Dec. 2016.
 "A flexible twosection transmissionline transformer design approach for complex source and real load impedances," X. Wang, M. Ohira, and Z. Ma, IEICE Electronics Express, vol.14, no.1, pp.20161095, Jan. 2017.
 "Dualband design theory for dual transmission line transformer," X. Wang, Z. Ma, and M. Ohira, IEEE Microwave and Wireless Comp. Lett., vol.27, no.9, pp.782784, Sept. 2017.
 "Theory and experiment of twosection tworesistor Wilkinson power divider with two arbitrary frequency bands," X. Wang, Z. Ma, and M. Ohira, IEEE Trans. on Microwave Theory and Tech., vo.66, no.3, pp.12911300, Mar. 2018.
 "Authors' reply," IEEE Microwave and Wireless Comp. Lett., X. Wang, T. Xie, G. Lu, Z. Ma, and M. Ohira, Oct. 2018.
Frequency Selective Surfaces (FSS)
 "Optimized singlelayer frequency selective surface and its experimental verification," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, in Proc. of 32nd European Microwave Conf. (EuMC 2002), pp.981984, Milan, Italy, Sep. 2002.
 "Multiband singlelayer frequency selective surface optimized by genetic algorithm with geometryrefinement technique," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, IEEE APS Int. Symp. Antennas Propagat. (APS 2003), Columbus, OH, June 2003.
 "A singular characteristic of singlelayer frequency selective surface with the element optimized by GA,"M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, IEEE Topical Conf. on Wireless Commun. Tech., no.s16p01, Honolulu, HI, Oct. 2003.
 "Equivalent circuit for frequency selective surface with complicated element extracted from eigenvalue analysis," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, Proc. of AsiaPacific Microwave Conf. (APMC 2004), Delhi, India, Dec. 2004.
 "Eightlegged resonant element for multiband FSS and its experimental verification," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, 2005 Int. Symp. on Antennas and Propagat. (ISAP 2005), pp.861864, Aug. 2005.
 "A highperformance frequency selective surface consisting of closelypacked eightlegged resonant elements," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, 2005 Korea Japan Microwave Workshop (KJMW 2005), pp.4649, Busan, Korea, Oct. 2005.
Antennas and Propagation
 "Varactorloaded invertedF multiport parasitic array radiator antenna," M. Ohira, A. Miura, M. Ueba, M. Taromaru, and T. Ohira, IEEE APS Int. Symp. Antennas Propagat. (APS 2007), pp.52115214, Honolulu, June 2007.
 "60GHz wideband shapedbeam antenna using closelyspaced waveguide slots for wireless LAN," M. Ohira, A. Miura, and M. Ueba, 2008 Int. Symp. on Antennas and Propagat. (ISAP 2008), pp.714717, Oct. 2008.
 "A bandwidthenhanced lowprofile antenna for inmachine wireless harness communications and its clearance distance evaluation," M. Ohira, IEEE APS Int. Symp. Antennas Propagat. Dig. (APS 2013), pp.978979, Orlando, FL, July 2013.
 "Microwave propagation characterization in automotive engine compartment for wireless harness communications," M. Ohira, S. Ano, S. Kitazawa, H. Ban, N. Kukutsu, and K. Kobayashi, IEEE APS Int. Symp. Antennas Propagat. Dig. (APS 2014), pp.11791180, Memphis, TN, July 2014.
 "Intraspacecraft wireless link and its application to spacecraft environmental tests," T. Toda, N. Kukutsu, S. Kitazawa, S. Ano, H. Kamoda, T. Kumagai, K. Kobayashi, M. Ohira, S. Shimizu, 30th Int. Symp. on Space Tech. and Science (ISTS), Kobe, Japan, July 2015.
 "On the design method of microstrip filtering antennas using only amplitude property of input reflection responses," M. Ohira and Z. Ma, 2015 ThailandJapan MicroWave (TJMW2015), Bangkok, Thailand, Aug. 2015. (Not published technical report)
 "An efficient design method of microstrip filtering antenna suitable for circuit synthesis theory of microwave bandpass filters," M. Ohira and Z. Ma, 2015 Int. Symp. on Antennas and Propagat. (ISAP2015), pp.846849, Hobart, Australia, Nov. 2015.
 "Design of multistage microstrip filtering antenna by using parameter extraction method," K. Sato, M. Ohira, and Z. Ma, Proc. of 2016 ThailandJapan MicroWave (TJMW2016), Bangkok, Thailand, June 2016. (Not published technical report)
 "Couplingmatrix based design of microstrip filtering antenna with cross coupling between antenna and resonator," M. Ohira, T. Miyazaki, Z. Ma, and X. Wang, Proc. of 2017 ThailandJapan MicroWave (TJMW2017), Bangkok, Thailand, June 2017. (Not published technical report)
 "Design of microstrip wideband filtering antenna using network synthesis theory of wideband chebyshev filter," M. Ohira, K. Sato, and Z. Ma, Proc. of 2018 ThailandJapan MicroWave (TJMW2018), Bangkok, Thailand, June 2018. (Not publsihed technical report)
Waveguide Filters
 "Novel waveguide filters with multiple attenuation poles using frequency selective surfaces," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, 2005 IEEE MTTS Int. Microwave Symp. (IMS 2005), Long Beach, CA, June 2005.
 "Circuit synthesis for compact waveguide filters with closelyspaced frequency selective surfaces," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, 10th Int. Symp. on Microwave and Optical Tech. (ISMOT 2005), pp.811814, Fukuoka, Japan, Aug. 2005.
 "A new dualbehavior FSS resonator for waveguide filter with multiple attenuation poles," M. Ohira, H. Deguchi, M. Tsuji, and H. Shigesawa, Proc. of 35th European Microwave Conf. (EuMC 2005), pp.189192, Paris, France, Oct. 2005.
 "A novel resonant window having dualbehavior resonance for pseudoelliptic waveguide filter," M. Ohira, H. Deguchi, and M. Tsuji, in Proc. of 36th European Microwave Conf. (EuMC 2006), pp.10831086, Manchester, UK, Oct. 2006.
 "A novel coaxialexcited FSSloaded waveguide filter with multiple transmission zeros," M. Ohira, Z. Ma, H. Deguchi, and M. Tsuji, Proc. of AsiaPacific Microwave Conf. (APMC 2010), pp.17201723, Yokohama, Japan, Dec. 2010.
 "A new type of compact evanescentmode waveguide bandpass filter using planar dualbahavior resonators," M. Ohira, T. Matsumoto, Z. Ma, H. Deguchi, and M. Tsuji, Proc. of AsiaPacific Microwave Conf. (IMS 2011), pp.10231026, Melbourne, Australia, Dec. 2011.
 “A cutoffwaveguide bandpass filter using antiresonant elements for sharp passband skirt and wide stopband characteristics,” M. Ohira, T. Matsumoto, and Z. Ma, Proc. of AsiaPacific Microwave Conf. (APMC 2013), pp.447449, Seoul, Korea, Nov. 2013.
Planar Filters
 "Multiresonator generation in arbitrarilyshaped planarcircuit filters by genetic optimization," A. Kido, H. Deguchi, M. Tsuji, and M. Ohira, Proc. of 37th European Microwave Conf. (EuMC 2007), pp.12411244, Munich, Germany, Oct. 2007.
 "Compact highperformance planar bandpass filters with arbitrarilyshaped conductor patches and slots," T. Kido, H. Deguchi, M. Tsuji, and M. Ohira, Proc. of 38th European Microwave Conf. (EuMC 2008), pp.11651168, Amsterdam, The Netherlands, Oct. 2008.
 "Resonantmode behavior of a new slotlineembedded threemode microstripline resonator and its filter application," M. Ohira, Z. Ma, and M. Kato, Proc. of 2011 ChinaJapan Joint Microwave Conf. (CJMW 2011), pp.326329, Hangzhou, China, Apr. 2011. (CJMW2011 (ChinaJapan Microwave Conference) Microwave Prize)
 "Characteristics and design formulas of a microstrip stubloaded multimode ring resonator," Z. Ma, M. Ohira, T. Hotaka, C.P. Chen, T. Anada, and Y. Kobayashi, Proc. of 2011 ChinaJapan Joint Microwave Conf. (CJMW 2011), pp.354357, Hangzhou, China, Apr. 2011.
 "Eigenmode analysis of a novel threemode microstrip/slotline resonator and the development of a compact bandpass filter with multiple transmission zeros and wide stopband property," M. Ohira and Z. Ma, 2011 IEEE MTTS Int. Microwave Symp. (IMS 2011), pp.14, Baltimore, MD, June 2011.
 "Design of a broadband bandpass filter using microstrip stubsloaded threemode resonator," Z. Ma, T. Kimura, M. Ohira, C.P. Chen, and T. Anada, Proc. of AsiaPacific Microwave Conf. (APMC 2011), pp.139142, Melbourne, Australia, Dec. 2011.
 "Novel multimode ring resonator transversal array bandpass filter with very high skirt selectivity using multiple transmission zeros," M. Ohira and Z. Ma, 2012 IEEE MTTS Int. Microwave Symp. (IMS 2012), Montreal, Canada, June 2012.
 "A novel compact highperformance microstrip 26GHz ultrawideband (UWB) bandpass filter for vehicle radar systems," Z. Ma, M. Ohira, C.P. Chen, and T. Anada, IEEE MTTS Int. Microw. Workshop Series on Millimeter Wave Wireless Tech. and Applications (IMWS 2012), Nanjing, China, Sep. 2012.
 "Compact bandpass filter with a sharp rolloff response using multipath coupling scheme of Hshaped resonator," M. Ohira and Z. Ma, Proc. of AsiaPacific Microwave Conf. (APMC 2012), pp.11301132, Kaohsiung, Taiwan, Dec. 2012.
 "Circuital modeling and physical understanding of dissipation effects for coupled resonator filters transformed into transversal array configuration," M. Ohira and Z. Ma, Proc. of 2013 Int. Symp. on Electromagnetic Theory (EMTS 2013), pp.5356, Hiroshima, Japan, May 2013.
 "Deterministic extraction of direct source/load coupling and its application to multimode filter designs based on transversal array network theory," M. Ohira, H. Aoyama, and Z. Ma, 2013 IEEE MTTS Int. Microwave Symp. (IMS 2013), Seattle, WA, June 2013.
 "Physical interpretation of frequencydependent S/L coupling in multimode bandpass filter and its design approach for generation of multiple finite transmission zeros," M. Ohira, H. Aoyama, and Z. Ma, 2014 IEEE MTTS Int. Microwave Symp. (IMS 2014), Tampa, FL, June 2014.
 "Design of a quasimillimeterwave UWB bandpass filter using microstrip dualmode ring resonator and halfwavelength resonators," Z. Ma, Y. Wang, M. Ohira, C.P. Chen, and T. Anada, The XXXI General Assembly of the International Union of Radio Science (URSI GASS 2014), Beijing, China, Aug. 2014.
 "Microstrip lowpass filters with improved frequency responses using coupledline hairpin resonators," J. Tsurumi, Z. Ma, and M. Ohira, Proc. of AsiaPacific Microwave Conf. (APMC 2014), pp.11541156, Sendai, Japan, Nov. 2014. (J. Tsurumi: APMC 2014 Student Prize)
 "A novel microstrip filter structure consisting of transversal resonator array and its fully canonical bandpass filter design," M. Ohira, T. Kato, and Z. Ma, 2015 IEEE MTTS Int. Microwave Symp. (IMS 2015), Phoenix, AZ, May 2015.
 "Novel microstrip realization and straightforward design of fully canonical CuldeSac coupling bandpass filters," M. Ohira, T. Kato, and Z. Ma, 2016 IEEE MTTS Int. Microwave Symp. (IMS2016), San Francisco, CA, May 2016.
 "A simple and fast tuning technique for directcoupled resonator filter design," R. Tomita, M. Ohira, and Z. Ma, Proc. of 2016 ThailandJapan MicroWave (TJMW2016), Bangkok, Thailand, June 2016. (Not published technical report) (R. Tomita: Young Researcher Encouragement Award)
 "Physical realization and systematic design of microwave bandpass filters with generalized Chebyshev function Response," M. Ohira and Z. Ma, Proc. of 2016 ThailandJapan MicroWave (TJMW2016), Bangkok, Thailand, June 2016.
 "A compact quasimillimeterwave microstrip wideband bandpass filter," Z. Ma, M. Ai, M. Ohira, C. Chen, and T. Anada, 2016 IEEE Int. Conf. on Ubiquitous Wireless Broadband, Najing, China, Oct. 2016.
 "A novel eigenmodebased neural network for fully automated microstrip bandpass filter design," M. Ohira, A. Yamashita, Z. Ma, and X. Wang, 2017 IEEE MTTS Int. Microwave Symp. (IMS2017), Honolulu, HI, June 2017.
 "Design of microstrip bandpass filters using neural network based on eigenmodes," A. Yamashita, M. Ohira, Z. Ma, and X. Wang, Proc. of 2017 ThailandJapan MicroWave (TJMW2017), Bangkok, Thailand, June 2017. (Not published technical report)
 "A fourthorder tunable bandpass filter with constant absolute bandwidth and transmission zeros," S. Hashimoto, M. Ohira, Z. Ma, and X. Wang, Proc. of 2017 ThailandJapan MicroWave (TJMW2017), Bangkok, Thailand, June 2017. (Not published technical report)
 "Design of a compact diplexer using dualmode microstrip and slotline resonators," B. Ren, Z. Ma, H. Liu, M. Ohira, P. Wen, X. Wang, and X. Guan, 2017 6th AsiaPacific Conf. on Antennas and Propagat. (APCAP2017), Xi'an, China, Oct. 2017.
 "Compact dualband bandpass filter using stubloaded stepped impedance resonators with mixed electric and magnetic couplings," P. Wen, Z. Ma, H. Liu, M. Ohira, B. Ren, and X. Wang, Proc. of 2017 AsiaPacific Microwave Conf. (APMC2017), pp.803805, Kuala Lumpur, Malaysia, Nov. 2017.
 "Differential dualband filter with flexible frequency ratio using Hshaped composite resonator for SCDMA and LTE applications," P. Wen, Z. Ma, M. Ohira, X. Wang, H. Liu, B. Ren, and X. Guan, Proc. of 2017 IEEE Electrical Design of Advanced Packaging and Systems (EDAPS 2017), Haining, Hangzhou, China, Dec. 2017.
 "A new microstrip bandstop filter for fully canonical CuldeSac coupling configuration," M. Ohira, M. Kanomata, Z. Ma, and X. Wang, Dig. of IEEE MTTS Int. Microwave Symp. (IMS2018), pp.708711, Philadelphia, PA, June 2018.
 "A novel microstrip symmetric diagonal crosscoupling quadruplet bandpass filter using even/oddmode stepped impedance resonators," R. Mikase, M. Ohira, Z. Ma, and X. Wang, Dig. of IEEE MTTS Int. Microwave Symp. (IMS2018), pp.712715, Philadelphia, PA, June 2018. (R. Mikase: IMS2018 Student Paper Competition Finalist)
 "[Invited] Automated microstrip bandpass filter design using feedforward and inverse models of neural network," M. Ohira, A. Yamashita, Z. Ma, and X. Wang, Proc. of 2018 AsiaPacific Microwave Conf. (APMC 2018), Kyoto, Japan, Nov. 2018.
 "Novel compact dualband BPF using stubloaded shorted steppedimpedance resonators," P. Wen, Z. Ma, H. Liu, S. Zhu, M. Ohira, C. Wang, X. Guan, and B. Ren, Proc. of 2018 AsiaPacific Microwave Conf. (APMC 2018), Kyoto, Japan, Nov. 2018.
 "Design of balanced dualband superconducting bandpass filter with high selectivity and deep commonmode suppression," B. Ren, Z. Ma, H. Liu, M. Ohira, X. Guan, and P. Wen, Proc. of 2018 AsiaPacific Microwave Conf. (APMC 2018), Kyoto, Japan, Nov. 2018.
Other Passive Circuits
 "Bandwidth enhancement of coaxial line to postwall waveguide transition using shortended straight post in 60ghz band," W. Luo, M. Ohira, A. Miura, and M. Ueba, Proc. of AsiaPacific Microwave Conf. (APMC 2008), pp.14, Hong Kong, China, Dec. 2008.
 "Dualband bandpass filter type Wilkinson power divider with microstrip composite resonators," X. Wang, N. Kimata, Z. Ma, and M Ohira, Proc. of 2017 AsiaPacific Microwave Conf. (APMC2017), pp.299301, Kuala Lumpur, Malaysia, Nov. 2017.
 "Compact tunable Wilkinson power divider with simple structure," X. Wang, Z. Ma, M. Ohira, C.P. Chen, and T. Anada, Proc. of 2018 Europ. Microwave Conf. (EuMC2018), Madrid, Spain, Sept. 2018.
 "Design theory of dualband Wilkinson power divider with different frequency ratio ranges," A. Song, X. Wang, Z. Ma, and M. Ohira, Proc. of 2018 AsiaPacific Microwave Conf. (APMC 2018), Kyoto, Japan, Nov. 2018.
Workshop
 M. Ohira, "A parameterextraction method for transversal resonator array bandpass filters and its applications to multimode filter designs," Workshop WS1D in 2014 AsiaPacific Microwave Conf. (APMC 2014), Sendai, Japan, Nov. 2014.
Tutorial talks
 M. Ohira, "Genetic Algorithm Design for Applications to Microwave Filters and Antennas," TJMW2012 (ThailandJapan MicroWave) Microwave Theory and Techniques Tutorial MW3, pp.87104, Chulalongkorn University, Bangkok, Thailand, Aug. 2012.
 H. Kayano and M. Ohira, "Fundamentals of Microwave Filters: Synthesis Theory and Design Techniques," TJMW2013 (ThailandJapan MicroWave) Short Courses: Tutorial 4, Kasetsart University, Bangkok, Thailand, Dec. 2013.
 M. Ohira, "Microwave planar bandpass filter design for student design competition," Tutorial Session of 2016 ThailandJapan MicroWave (TJMW2016), KMUTNB, Bangkok, Thailand, June 2016.
Synfornee: Synthesis for Filter Network Elements
(1) Synfornee Lite (Freeware in Japanese)
 Synthesize a coupling matrix of direct resonator coupled bandpass filters having Chebyshev and Butterworth functions
 Calculate coupling coefficients and external Q factors in bandpass frequency domain from coupling matrix in lowpass prototype freqeuncy domain.
 Calculate frequency responses of BPF from coupling matrix in lowpass prototype freqeuncy domain..
 Calculate frequency responses of BPF by inputting arbitrary values in coupling matrix.
 Visually show a coupling matrix in matrix form.
 Visually show frequency responses of Sparameters in graphs.
 Save Sparameters as CSV files.
 Save and copy coupling matrix as CSV file.
 Read coupling matrix from CSV file.
Basic Functions
GUI
Read and Save
Freeware：
Download
Current Version 0.60 in Japanese（Updated on Apr. 19, 2018）
Notes:
(1) This software is compatible with Windows 7, Windows 8, Windows 10.
(2) This software requires .NET Framework 4.5.2.
(3) I am not responsible for any damage caused by this software.
(4) Calculation accuracy is not guaranteed for all settings, because approximation is used for coupling matrix calculation.
(5) There may be bugs ... m(_ _)m
Request:
If you write papers using this software, it will encourage development if you cite my software in Reference as follows. (The format is not limited to the bottom)
Current Version 0.60 in Japanese（Updated on Apr. 19, 2018）
Notes:
(1) This software is compatible with Windows 7, Windows 8, Windows 10.
(2) This software requires .NET Framework 4.5.2.
(3) I am not responsible for any damage caused by this software.
(4) Calculation accuracy is not guaranteed for all settings, because approximation is used for coupling matrix calculation.
(5) There may be bugs ... m(_ _)m
Request:
If you write papers using this software, it will encourage development if you cite my software in Reference as follows. (The format is not limited to the bottom)

[1] M. Ohira, Synfornee Lite Ver. 0.50 [Software]. Available: http://sirius.reso.ees.saitamau.ac.jp/ohiram.html
(2) Synfornee (Full version in Japanese)
 Synthesize a coupling matrix of transversal array filters (BPF and BSF) having a generalized Chebyshev function.
 Synthesize a coupling matrix of direct resonator coupled bandpass filters having Chebyshev and Butterworth functions
 Calculate coupling coefficients and external Q factors in bandpass frequency domain from coupling matrix in lowpass prototype freqeuncy domain.
 Calculate frequency responses of BPF from coupling matrix in lowpass prototype freqeuncy domain..
 Calculate frequency responses of BPF by inputting arbitrary values in coupling matrix.
 Calculate frequency responses in lowpass prototype frequency domain as well.
 Transform coupling topology from transversal coupling to other couplings such as folded canonical and fullycanonical CuldeSac coupling.
 Calculate frequency responses of lossy filter by inputting unloaded Q factor of each resonator.
 Calculate frequency responses of S11 and S21 phases．
 Calculate frequency responses of group delay．
 Calcualte frequency responses of stored energy of each resonator for 1Wpower input.
 Visually show a coupling matrix in matrix form.
 Visually show frequency responses of Sparameters in graphs.
 Save Sparameters as CSV files.
 Save and copy coupling matrix as CSV file.
 Read coupling matrix from CSV file.
Basic Functions
Advanced Functions
GUI
Read and Save
References
 R. J. Cameron, R. Mansour, C. M. Kudsia, Microwave Filters for Communication Systems: Fundamentals, Design and Applications, July 2007.
 M. Ohira, "Introduction to theory, analysis, and design of microwave filters in new era of wireless," Microwave Workshops & Exhibition (MWE 2015), WE4B (in Japanese), Nov. 2015.
 M. Ohira and Z. Ma, "Theoretical relations between unloaded Q factor, stored energy, group delay, and insertion loss derived from coupling matrix of filter circuit," IEICE Tech. Report (in Japanese), vol.117, no.17, MW201717, pp.5560, May 2017.
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