著者

Ryoya HONDA Minoru MIZUTANI Masaya TAMURA Takashi OHIRA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Electronics (ISSN:09168516)

巻号頁・発行日

vol.E106-C, no.11, pp.698-706, 2023-11-01

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This paper formulates a class-E synchronous RF rectifier from a new viewpoint. The key point is to introduce a matrix and convolute the DC terms into RF matrices. The explicit expression of input impedance is demonstrated in plane geometry. We find out their input impedance exhibits a geodesic arc in hyperbolic geometry under ZVS operation, where the theoretical RF-DC conversion efficiency results in 100%. We verify the developed theory both numerically (circuit simulation) and experimentally (6.78MHz, 100W). We confirm that the input impedance becomes a geodesic arc for a wide range of DC load resistance. The presented theory is quite elegant since it is based on a matrix-based formulation and plane-geometrical expression.

著者

Marimo MATSUMOTO Masaya TAMURA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Electronics (ISSN:09168516)

巻号頁・発行日

vol.E105-C, no.9, pp.398-406, 2022-09-01

被引用文献数

2

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Couplers in a film-type capacitive wireless power charging (CWC) system for an implantable medical device were designed and analyzed in this work. Due to the high conductivity of the human body, two paths contribute to the power transmission, namely a high-frequency current and an electric field. This was confirmed by an equivalent circuit of the system. During analysis of the system, we used pig skin with subcutaneous fat, which has a high affinity with the human body, to search for a highly efficient electrode shape. Subsequently, we fabricated the designed coupler and measured ηmax. An ηmax of 56.6% was obtained for a half-circular coupler with a radius of 20 mm and a distance of 10 mm between adjacent couplers. This study will contribute to the realization of implantable devices that can be recharged during breaks or while sleeping at home and is expected to significantly reduce the burden on patients.

著者

Yasumasa Naka Masaya Tamura

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE Communications Express (ISSN:21870136)

巻号頁・発行日

vol.9, no.10, pp.457-463, 2020-10-01 (Released:2020-10-01)

参考文献数

8

被引用文献数

1

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Capacitive wireless power transfer is performed using large electrodes or using a medium having high relative permittivity such as water. The transfer efficiency demonstrates a pronounced change with frequency. A lumped-constant equivalent circuit with parasitic elements represents the change. However, a relationship between conditions for generating minimum/maximum values of the transfer efficiency and structural parameters of the electrodes in the coupler has not clarified. In this study, an equivalent circuit is proposed using a distributed-constant circuit. We converted the lumped-constant circuit into two open-ended directional couplers. From the result, we derived the conditions for generating the minimum and maximum values of the voltage input/output ratio. The efficiencies calculated by the distributed-constant circuit and electromagnetic simulation were in good agreement.