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Preliminary study of 50 W Class-E GaN FET amplifier for 6.78 MHz capacitive wireless power transfer Muharam, Aam; Mostafa, Tarek Mahmoud; Ahmad, Suziana; Masuda, Mitsuru; Obara, Daiki; Hattori, Reiji; Hapid, Abdul
Journal of Mechatronics, Electrical Power and Vehicular Technology Vol 11, No 1 (2020)
Publisher : Research Centre for Electrical Power and Mechatronics, Indonesian Istitutes of Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/j.mev.2020.v11.22-29

Abstract

A preliminary study of Class-E radio frequency power amplifier for wireless capacitive power transfer (CPT) system is presented in this paper. Due to a limitation in coupling capacitance value, a high frequency operation of switching power inverter is necessary for the CPT system. A GaN MOSFET offers reliability and performance in a high frequency operation with an improved efficiency over a silicon device. Design specification related to the parallel load parameter, LC impedance matching and experimental analysis of the amplifier is explored. An experimental setup for the proposed inverter and its integration with the CPT system is provided, and the power efficiency is investigated. As a result, by utilizing a 6.78 MHz resonant frequency and a 50 Ω resistive load, 50 W of power has been transmitted successfully with an end to end system efficiency over 81 %. Additionally, above 17 W wireless power transfer was demonstrated successfully in the CPT system under 6 pF coupling with the efficiency over 70 %.
Optical Ray Tracing Simulation by Using Monte Carlo Method for Reflectance-based Photoplethysmography Sensor in Human Skin and Fingertip Model Misran, Muhamad Affiq Bin; Bilgaiyan, Anubha; Hattori, Reiji
Computational And Experimental Research In Materials And Renewable Energy Vol 5 No 2 (2022): November
Publisher : Physics Department, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/cerimre.v5i2.31668

Abstract

The pulse oximetry device has been used for decades to monitor human pulse rate and oxygen saturation. There are two types of pulse oximetry which are transmission and reflection based. However, most devices are unsuitable for daily health monitoring due to the bulkiness and inconvenience of long-term monitoring while continuously doing everyday activities. Therefore, developing a wearable device such as a patch would benefit the users. Several factors can be considered for such a system. One of them is the distance between the source and detector since both are the major components of this system. However, there is still a lack of information in this regard. This study used the ray-tracing Monte Carlo method to simulate transmittance and reflectance-based oximetry principles with a 663 nm wavelength as the light source. The results show the ray tracing behavior from the light source to the photodetector in the biological tissue under two different structures mentioned previously. The separation between the light source and the detector should be less than 3 mm for the reflection type. A significant difference was observed for a distance greater than 3 mm compared with the transmission-based, which has a higher photocurrent even at a 7 mm distance. However, this transmission-based device is limited to the placement of the device on the body part. It is due to the thickness, which varies depending on the body parts themselves. Therefore, wearable pulse oximetry devices with the reflectance-based principle are better due to higher signal acquisition than the transmittance-based, especially for the daily health monitoring system. Furthermore, it also can be used throughout any body part. This reflection-based device can fully utilize microfabrication to integrate the light source and photodetector.Keywords: PPG sensor, Monte Carlo, tissue optics, pulse oximetry, photoplethysmography.