Power station under seawater

Autonomous underwater vehicles are desired to charge battery and communicate information under water in order to improve operation efficiency. We have an ambitious goal of developing the wireless power and data transfer system for operation underwater, focusing on the capacitive coupling with a simple structure and low leakage of field. So as to require a high power charging in this case, we are also investigating an elucidation of high-frequency property in fresh water and seawater.

[1] M. Tamura, K. Murai, M. Matsumoto, “Design of Conductive Coupler for Underwater Wireless Power and Data Transfer,” IEEE Trans. Microwave Theory and Techniques, vol. 69, no. 1, pp.1161-1175, Jan. 2021.
[2] M. Tamura, Y. Naka, K. Murai, T. Nakata,“Design of a Capacitive Wireless Power Transfer System for Operation in Fresh Water,” IEEE Trans. Microwave Theory and Techniques, vol. 66, no. 12, pp.5873-5884, Dec. 2018.
[3] Y. Naka, K. Yamamoto, T. Nakata, M. Tamura, “Improvement in Efficiency of Underwater Wireless Power Transfer with Electric Coupling,” IEICE Trans. Electron, vol. E100-C, no. 10, pp.850-857, Oct. 2017.

Base station for next-generation network

Various methods in order to achieve high-speed and large-capacity wireless communications are developed such as Massive-MIMO, In-band full-duplex, and OAM. We aim to develop the RF circuits that are key technologies to realize these methods. As we image the application to a wide target range from portable devices to base station in small cell, we are developing value-added solutions such as high tunability and high power capability corresponding to the targets.

[1] K. Yoshihara, M. Tamura, Y. Miyaji, A. Alphones, “Dual Band SIW Cavity-Backed Crossed-Slot Antenna,” in Proc. 2019 Asia-Pacific Microwave Conference, Singapore, Dec. 2019, pp.1775-1778.
[2] K. Satoh, M. Tamura,“Filter using cylindrical quadruple mode SIW resonator,” IEICE Electronics Express, ELEX, vol.15, No.9, pp.1-6, #20180295, Apr. 2018.
[3] M. Tamura, S. Tomida, K. Ichinose,“Design and Analysis of Multi-Mode Stripline Resonator and Its Application to Bandpass Filter,” IEICE Trans. Electron, vol. E101-C, no. 3, pp.151-160, Mar. 2018.

Battery-less wireless sensor system

Numerous sensors are installed in various facilities and equipment for the purpose to support safe and secure life. In particular, power supply by wireless power transfer is expected for the sensors in dangerous places such as infrastructures in factory and power plant. We are developing a unique system with the pseudo-shielded space, which makes it possible to confine the electromagnetic field in the space and communicate with the sensors outside the space.

[1] S. Nimura, D. Furusu, M. Tamura,“Improvement in Power Transmission Efficiency for Cavity Resonance-Enabled Wireless Power Transfer by Utilizing Probes With Variable Reactance,” IEEE Trans. Microwave Theory and Techniques, vol. 68, no. 7, pp.2734-2744, Jul. 2020.
[2] D. Furusu, M. Tamura,“Design of Capacitive Planar Power Transmitter and Receiver for Cavity Resonance enabled Wireless Power Transfer,” IEEE Microwave and Wireless Components Letters, vol. 29, no. 8, pp.566-568, Aug. 2019.
[3] I. Takano, D. Furusu, Y. Watanabe, M. Tamura, “Cavity Resonator Wireless Power Transfer in an Enclosed Space with Scatterers utilizing Metal Mesh,” IEICE Trans. Electron, vol. E100-C, no. 10, pp.841-849, Oct. 2017.