Synthesis loss in receiving array antennas and transmission efficiency in the Fresnel region

Kojima Seishiro; Shinohara Naoki; Mitani Tomohiko; Kojima Seishiro; Shinohara Naoki; Mitani Tomohiko

doi:10.1017/wpt.2017.10

2017 Volume 4

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Synthesis loss in receiving array antennas and transmission efficiency in the Fresnel region

Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, Japan

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Author Bio:
Seishiro Kojima received B.E. degree in Electrical and Electronic Engineering and M.E. in Electric Engineering from the University of Kyoto in 2015 and 2017, respectively. Currently, he is pursuing the Ph.D. degree in Electric Engineering. He is a student member of the IEEE and IEICE.

Naoki Shinohara received the B.E. degree in Electronic Engineering, the M.E. and Ph.D. (Eng.) degrees in Electrical Engineering from Kyoto University, Japan, in 1991, 1993, and 1996, respectively. He was a research associate in Kyoto University from 1996. From 2010, he has been a professor in Kyoto University. He has been engaged in research on Solar Power Station/Satellite and Microwave Power Transmission system. He is IEEE MTT-S Technical Committee 26 (Wireless Power Transfer and Conversion) vice chair, IEEE MTT-S Kansai Chapter TPC member, IEEE Wireless Power Transfer Conference advisory committee member, International Journal of Wireless Power Transfer (Cambridge Press) executive editor, technical committee on IEICE Wireless Power Transfer, communications society member, Japan Society of Electromagnetic Wave Energy Applications vice president, Space Solar Power Systems Society board member, Wireless Power Transfer Consortium for Practical Applications (WiPoT) chair, and Wireless Power Management Consortium (WPMc) chair.

Tomohiko Mitani received the B.E. degree in Electrical and Electronic engineering, M.E. degree in Informatics, and Ph.D. degree in Electrical Engineering from Kyoto University, Kyoto, Japan, in 1999, 2001, and 2006, respectively. In 2003, he was an Assistant Professor with the Radio Science Center for Space and Atmosphere, Kyoto University. Since 2012, he has been an Associate Professor with the Research Institute for Sustainable Humanosphere, Kyoto University. His current research interests include the experimental study of magnetrons, microwave power transmission systems, and applied microwave engineering. Dr. Mitani is a member of the Institute of Electronics, Information and Communication Engineers (IEICE) and the Japan Society of Electromagnetic Wave Energy Applications (JEMEA). He has been a board member of JEMEA since 2015. He has been the treasurer of IEEE MTT-S Kansai Chapter since 2014
Corresponding author: S. Kojima Email: seishiro_kojima@rish.kyoto-u.ac.jp

Wireless Power Transfer 2017, 4(2): 120-131 | Cite this article

Abstract

We address transmission between array antennas in the Fresnel region, where there is a difference between the theoretical and actual transmission efficiencies. In particular, we focus on the effect of synthesis loss in the receiving antenna's power combiner circuit caused by amplitude and phase differences among the signals received by the elements. We designed 24 GHz array antennas and investigated the effect of synthesis loss on transmission efficiency via simulation. The synthesis loss was found to increase for smaller transmitting antenna sizes and larger receiving antenna sizes. In addition, to clarify the origin of the discrepancy between the theoretical and actual efficiency values and accurately estimate the efficiency, we defined four other loss factors and calculated them via simulation. Based on the results obtained, we propose an approximate equation for transmission efficiency in terms of synthesis loss and aperture efficiency. Finally, we calculate the efficiency with the effect of the loss factors included and confirm that the calculated and measured efficiencies are almost identical.
- Millimeter wave,
- Fresnel region,
- Synthesis loss,
- Array antenna,
- Wireless power transfer (WPT)

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Kojima S, Shinohara N, Mitani T. 2017. Synthesis loss in receiving array antennas and transmission efficiency in the Fresnel region. Wireless Power Transfer 4(2): 120-131 doi: 10.1017/wpt.2017.10

Kojima S, Shinohara N, Mitani T. 2017. Synthesis loss in receiving array antennas and transmission efficiency in the Fresnel region. Wireless Power Transfer 4(2): 120-131 doi: 10.1017/wpt.2017.10

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Synthesis loss in receiving array antennas and transmission efficiency in the Fresnel region

Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, Japan

Author Bio:
Seishiro Kojima received B.E. degree in Electrical and Electronic Engineering and M.E. in Electric Engineering from the University of Kyoto in 2015 and 2017, respectively. Currently, he is pursuing the Ph.D. degree in Electric Engineering. He is a student member of the IEEE and IEICE.

Naoki Shinohara received the B.E. degree in Electronic Engineering, the M.E. and Ph.D. (Eng.) degrees in Electrical Engineering from Kyoto University, Japan, in 1991, 1993, and 1996, respectively. He was a research associate in Kyoto University from 1996. From 2010, he has been a professor in Kyoto University. He has been engaged in research on Solar Power Station/Satellite and Microwave Power Transmission system. He is IEEE MTT-S Technical Committee 26 (Wireless Power Transfer and Conversion) vice chair, IEEE MTT-S Kansai Chapter TPC member, IEEE Wireless Power Transfer Conference advisory committee member, International Journal of Wireless Power Transfer (Cambridge Press) executive editor, technical committee on IEICE Wireless Power Transfer, communications society member, Japan Society of Electromagnetic Wave Energy Applications vice president, Space Solar Power Systems Society board member, Wireless Power Transfer Consortium for Practical Applications (WiPoT) chair, and Wireless Power Management Consortium (WPMc) chair.

Tomohiko Mitani received the B.E. degree in Electrical and Electronic engineering, M.E. degree in Informatics, and Ph.D. degree in Electrical Engineering from Kyoto University, Kyoto, Japan, in 1999, 2001, and 2006, respectively. In 2003, he was an Assistant Professor with the Radio Science Center for Space and Atmosphere, Kyoto University. Since 2012, he has been an Associate Professor with the Research Institute for Sustainable Humanosphere, Kyoto University. His current research interests include the experimental study of magnetrons, microwave power transmission systems, and applied microwave engineering. Dr. Mitani is a member of the Institute of Electronics, Information and Communication Engineers (IEICE) and the Japan Society of Electromagnetic Wave Energy Applications (JEMEA). He has been a board member of JEMEA since 2015. He has been the treasurer of IEEE MTT-S Kansai Chapter since 2014
Corresponding author: S. Kojima Email: seishiro_kojima@rish.kyoto-u.ac.jp

Wireless Power Transfer 4, Article number: 10.1017/wpt.2017.10 (2017) | Cite this article

Abstract: We address transmission between array antennas in the Fresnel region, where there is a difference between the theoretical and actual transmission efficiencies. In particular, we focus on the effect of synthesis loss in the receiving antenna's power combiner circuit caused by amplitude and phase differences among the signals received by the elements. We designed 24 GHz array antennas and investigated the effect of synthesis loss on transmission efficiency via simulation. The synthesis loss was found to increase for smaller transmitting antenna sizes and larger receiving antenna sizes. In addition, to clarify the origin of the discrepancy between the theoretical and actual efficiency values and accurately estimate the efficiency, we defined four other loss factors and calculated them via simulation. Based on the results obtained, we propose an approximate equation for transmission efficiency in terms of synthesis loss and aperture efficiency. Finally, we calculate the efficiency with the effect of the loss factors included and confirm that the calculated and measured efficiencies are almost identical.

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About this article

Cite this article

Kojima S, Shinohara N, Mitani T. 2017. Synthesis loss in receiving array antennas and transmission efficiency in the Fresnel region. Wireless Power Transfer 4(2): 120-131 doi: 10.1017/wpt.2017.10

Kojima S, Shinohara N, Mitani T. 2017. Synthesis loss in receiving array antennas and transmission efficiency in the Fresnel region. Wireless Power Transfer 4(2): 120-131 doi: 10.1017/wpt.2017.10