研究者業績
基本情報
- 所属
- 千葉大学 フロンティア医工学センター 准教授
- 学位
- 博士(工学)(東京工業大学)Ph.D.(東京工業大学)
- J-GLOBAL ID
- 200901040108092262
- researchmap会員ID
- 1000169309
- 外部リンク
受賞
21-
2022年3月
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2021年9月
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2020年9月
論文
179-
Bulletin of Glaciological Research 42 19-37 2024年6月 査読有り
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IEICE Communications Express 13(6) 168-171 2024年6月 査読有り最終著者責任著者
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IEEE Open Journal of Antennas and Propagation 5(2) 340-535 2024年4月 査読有りMeander Line Antenna (MLA) is widely employed in compact electronic devices, such as cellular phones and WLAN terminals, owing to its electrically small size. To facilitate practical antenna design, essential equations encompassing self-resonant structure, input resistance, antenna efficiency, and Q factor have been systematically developed. However, the prior self-resonant equations included only inductive reactance (XC), neglecting the capacitive reactance (XD) equation. This manuscript addresses this gap by introducing new design equations, presenting a newly derived XD equation and an improved Q factor expression. The inadequacies of the existing Q factor equation, reliant on the radius of a sphere encompassing the antenna, are addressed by proposing a more fitting expression that incorporates antenna structural parameters using the ratio of reactance to resistance. The overview of existing design equations sets the stage for the introduction of these newly developed equations. To assess the accuracy of electromagnetic (EM) simulation results, a comparative analysis is conducted between simulated and theoretically calculated input resistance values. The derivation of new reactance equations involves the development of XC equations based on electromagnetic theory. The XD equation is established by deriving the stored charge equation from electrical near-field distributions obtained through EM simulations. By applying the relationship between charge and capacitance, a new XD equation is obtained. Subsequently, a new self-resonant equation is derived, and the validity of the newly derived equations is confirmed through EM simulation results, ensuring their accuracy. Two MLA prototypes, with lengths of 0.05 and 0.1 wavelengths at 405 MHz, are fabricated and experimentally validated. Smith chart measurements confirm the self-resonant condition and input resistance. By correlating with the VSWR characteristics, the obtained Q factor of approximately 100 aligns successfully with the results from the reactance equation. The antenna gain is verified at -7.7 dBi and -3.5 dBi for antennas with lengths of 0.05 and 0.1 wavelengths, respectively. These findings establish the practical applicability of the proposed equations for antenna design and elucidate the performance of practical antennas.
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e28061-e28061 2024年3月 査読有り最終著者
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IEICE Transactions on Communications E107-B(1) 206-213 2024年1月1日 査読有り最終著者責任著者
MISC
623-
IEICE Proceeding Series (63) F2-3 2020年
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ロボティクス・メカトロニクス講演会講演概要集 2020 2P2-I05 2020年<p>Under-the-ice survey with underwater robots in Arctic is important to understand the global warming mechanism. We are currently studying localization method under-the-ice because acoustical positioning system does not use there. In this report, a new method of under-the-ice localization is proposed.</p>
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2019 International Symposium on Antennas and Propagation, ISAP 2019 - Proceedings 2019年10月Capsule endoscope is an innovative imaging device which offers less invasive procedure than conventional wired endoscope for the monitoring internal digestive tract in medical diagnosis. In order to improve the power transmission efficiency of the moving capsule, analysis on position estimation was conducted using Received Signal Strength algorithm in high-definition numerical human body model. As a result, an estimation error within 40 mm was achieved at about 80% of all the examination points.
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2019 International Symposium on Antennas and Propagation, ISAP 2019 - Proceedings 2019年10月In recent years, a capsule endoscopy has been used as one of the medical devices that can diagnose small intestines painlessly. Wireless power transmission (WPT) to the capsule endoscopy has been studied, and the efficiency of the WPT can be improved by using location information of the capsule. In the previous research, a localization method for the WPT to the capsule was developed in simulation. The purpose of this paper is to investigate whether the localization method can be applied to the localization of the capsule with the transmit and receive antennas for the WPT. We evaluated the algorithm developed in the previous research, so that the effectiveness of the algorithm was shown.
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2019 International Symposium on Antennas and Propagation, ISAP 2019 - Proceedings 2019年10月Recently, various electromagnetic (EM) applications have become common, and humans are frequently exposed to EM waves. Therefore, the effect of EM waves on the human body should be evaluated. In this study, we focused on the specific absorption rate (SAR) due to EM waves emitted from a smartphone, developed a numerical smartphone model, and confirmed its validity.
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2019 International Symposium on Antennas and Propagation, ISAP 2019 - Proceedings (63) A3-4 2019年10月Bedsores are injuries caused by pressure on the skin for a long time and stagnation of blood flow. The more such injuries progress, the longer the treatment period becomes. In some serious cases, surgery is required. Therefore, an early detection method is important. In this study, we develop a non-contact bedsore detection system by using electromagnetic waves. In this paper, we investigate a method using wavelet transforms to develop a more accurate bedsore detection method.
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ICECOM 2019 - 23rd International Conference on Applied Electromagnetics and Communications, Proceedings 69(8) 4967-4974 2019年9月 査読有り責任著者When divers rescue people from accidents at sea, they are in danger because of obstacles floating in the sea. If divers can confirm their own position, their activities will become much safer. In this study, assuming that we specify the positions of the divers performing rescue operations, to support their work, we investigate an undersea positioning technology using electromagnetic waves with low frequencies, i.e., 10-kHz. In previous studies, an ultra-long wave of 10-kHz was theoretically attenuated at 3.5 dB/m. In addition, a simulation of position estimation in the vertical section of the sea was reported. In this study, we indicate the superiority of using Receiving Signal Strength (RSS) to the phase difference between a transmitted and received signal. We also investigate an algorithm for position estimation wherein the antenna characteristics and two propagating rays of electromagnetic waves at sea are considered. Finally, we estimate the position of the transmitting antenna at depths of 1 to 8 m using our algorithm.
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IFIP Wireless Days 2019-April 2019年4月In recent years, in a hospital, a biological information monitoring system that constantly monitors biological information such as blood pressure and heart rate to grasp a patient's condition is generally used. However, in the current system, 420 to 450 MHz band are mainly used, and it is difficult to manage such as channel switching and device addition/deletion to wireless communication experts. Also, there is a problem that a transmitter having a size as large as a small terminal must be carried around. Therefore, we proposed the textile antenna using the 5.2 GHz band as a transmitting antenna of the system. In this paper, we report on the antenna characteristics when a transmitting antenna designed by the authors is placed on the human body and the result of received power transmitted by the textile antenna analysis in an imitated actual environment model.
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2018 IEEE International Workshop on Electromagnetics: Applications and Student Innovation Competition, iWEM 2018 2018年11月14日Recently, the capsular endoscope that has extra function has been investigated. Although the power consumption tends to increase as the ability increases, it is difficult to increase the capacity of the battery due to the volumetric problem. In this study, we proposed an antenna for both wireless power transmission and image transmission to be mounted on a capsule endoscope. In this paper, we proposed antennas to be mounted in a capsular endoscope and external on the body.
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2018 IEEE International Workshop on Electromagnetics: Applications and Student Innovation Competition, iWEM 2018 2018年11月14日Wireless capsule endoscopy is a medical device that examines the human gastrointestinal (GI) tract without burdening patients. Wireless power transmission technology of the capsule endoscope has been researched, and getting the capsule location is important to improve the power transmission efficiency. In this report, we try to develop a localization method for wireless power transmission. An algorithm corresponding to both horizontally and vertically polarized waves is developed, and the performance is evaluated by three-dimensional localization with eight receiving antennas.
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 118(53) 7-10 2018年5月24日
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117(490) 13-18 2018年3月8日
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117(490) 5-8 2018年3月8日
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117(466) 101-104 2018年3月2日
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2018 IEEE Antennas and Propagation Society International Symposium and USNC/URSI National Radio Science Meeting, APSURSI 2018 - Proceedings 1295-1296 2018年Recently, a biological information monitoring system that constantly monitors patient's information has been used in a hospital. However, these systems have a problem with patients' movement restrictions by sensor cables and transmitters. In addition, 2.4 GHz band congestion has occurred to increase the number of the devices using the wireless LAN in a hospital. This paper proposed a 5.2 GHz band textile antenna as transmitting antenna for biological information monitoring system. Proposed antenna was designed to transmit both polarizations, were confirmed to work well by experiment.
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2017 International Symposium on Antennas and Propagation, ISAP 2017 2017-January 1-2 2017年12月19日To design antennas for underwater communication systems using LF band, the transmission factor of dipole antennas with the sheath immersed in seawater are investigated by numerical study. Comparison of antenna characteristics between dipole antennas with different sheath structure is presented.
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2017 International Symposium on Antennas and Propagation, ISAP 2017 2017-January 1-2 2017年12月19日In recent years, capsule endoscopy has attracted attention as a medical device that examines the internal digestive tract without burdening the patient. Wireless power transmission of the capsule endoscope is researching now, and the power transmission efficiency can be improved by knowing the capsule location. In this report, we try to use the three-dimensional localization method with five antennas.
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117(318) 33-37 2017年11月21日
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117(318) 21-26 2017年11月21日
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117(318) 15-20 2017年11月21日
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OCEANS 2017 - Aberdeen 2017-October 1-5 2017年10月25日In 1998, JAMSTEC started the development project of the first prototype of a long-range cruising AUV (LCAUV) to evaluate fundamental technologies needed to travel through under the ice covered area of the Arctic. In 2005, The LCAUV, Urashima, achieved 317 km continuous cruising powered by a deep sea fuel cell developed in JAMSTEC [1]. We then moved to next stage and have conducted to design the second prototype LCAUV with target range of over 3,000 km. It included improvement of power source, communication system, and positioning system. In 2010 a small high efficiency multi-less (HEML) fuel cell was completed [2] and a long range acoustic communication system achieved 1,000 km communication using time-reversal waves. But we had not developed practical positioning system for under the ice by 2010. In past years the dramatic melting of Arctic ice would be driving extreme weather. This is very serious problem, but it is still poorly understood. Scientists need more research to understand it. We have thus a plan to develop an Arctic research platform that especially performs observations under the ice. Now we are conducting a research of a new positioning method with communication availability before developing the platform or an AUV. The proposed method is based on low frequency electromagnetic waves which can propagate inside of ice and sea water. A prototype to evaluate the method is like GPS repeater. The repeater to be set on the ice receives GPS signal, transmitting radio waves into the sea water via the ice up to several tens meters deep. To realize the system feasibility we started developing underwater antennas and measuring wave propagation in the sea ice and the sea water in 2016.
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Proceedings of the 2017 19th International Conference on Electromagnetics in Advanced Applications, ICEAA 2017 1151-1153 2017年10月11日Recently, various studies of capsular endoscope have been investigated. It has some disadvantage such as limited driving time and inconvenience of taking pictures cause of batteries that has limited capacity. If capsular endoscope operates by wireless transmission instead of cell batteries, we do not have to consider how improve the driving time and number of pictures. This paper presents a film antenna made by flexible printed circuit (FPC) for capsular endoscope. The antenna works with microwave wireless power transmission By this method, it is unnecessary to install a coil which is indispensable for the induction method in a capsule. Furthermore the antenna can be used by not only wireless power transmission but also captured images transmission. We confirmed that the designed antenna has good performance at the 433.92 MHz.
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電気学会研究会資料. SPC = The papers of technical meeting on semiconductor power converter, IEE Japan 2017(104) 37-41 2017年7月27日
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電気学会研究会資料. SPC = The papers of technical meeting on semiconductor power converter, IEE Japan 2017(104) 31-36 2017年7月27日
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117(158) 37-41 2017年7月27日
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117(158) 31-36 2017年7月27日
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117(157) 37-41 2017年7月27日
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117(157) 31-36 2017年7月27日
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 116(526) 27-30 2017年3月16日
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 116(454) 5-10 2017年2月16日
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 116(345) 11-16 2016年12月8日
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2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016 - Proceedings 885-886 2016年10月25日In recent years, electromagnetic (EM) applications have become common, and the opportunities of using the devices emitting EM waves have become increasing. Therefore, influences for the human body exposed to EM waves have been investigated and reported. However, there are few studies about EM exposure due to novel mobile phones such as smartphones. In this study, we developed the realistic computational smartphone model for the EM wave source. Furthermore, we estimated specific absorption rate (SAR) for the human body from the smartphone model placed in front of the abdomen.
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2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016 - Proceedings 2199-2200 2016年10月25日Recently, the technology of MIMO (Multiple-Input Multiple-Output) using multiple antennas and CA (Carrier Aggregation) using multiple frequency bands are introduced in a mobile terminal. If plural MIMO antennas are installed closely, mutual coupling between the antennas must be reduced to suppress deterioration of radiation efficiency and increase of the correlation coefficient. In previous studies, a decoupling method for single-band using bifurcation elements has been confirmed. However, if operating for single-band, it is not possible to introduce CA technology. This paper proposes a decoupling method for dual-band using trifurcation elements.
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電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 116(218) 25-28 2016年9月15日
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電子情報通信学会誌 = The journal of the Institute of Electronics, Information and Communication Engineers 99(8) 846-851 2016年8月
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電子情報通信学会総合大会講演論文集 2016(1) 69-69 2016年3月1日
書籍等出版物
11-
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Wiley-IEEE Press 2014年8月25日 (ISBN: 9781118388617, 1118388615) -
講演・口頭発表等
113-
電子情報通信学会総合大会講演論文集 2013年3月5日 一般社団法人電子情報通信学会
Works(作品等)
12共同研究・競争的資金等の研究課題
19-
日本学術振興会 科学研究費助成事業 2023年4月 - 2026年3月
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日本学術振興会 科学研究費助成事業 2023年4月 - 2026年3月
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日本学術振興会 科学研究費助成事業 2022年4月 - 2025年3月
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日本学術振興会 科学研究費助成事業 2022年4月 - 2025年3月
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日本学術振興会 科学研究費助成事業 基盤研究(B) 2022年4月 - 2025年3月