九州大学 研究者情報
著書一覧
POKHAREL RAMESH KUMAR(ぽかれる らめしゆ くまーる) データ更新日:2021.08.06

教授 /  システム情報科学研究院 I&Eビジョナリー特別部門 http://rfic.ed.kyushu-u.ac.jp/


著書
1. Mohamed Aboualalaa, Hala Elsadek and Ramesh K. Pokharel, WPT, Recent Techniques for Improving System Efficiency, Online, 10.5772/intechopen.96003, 1-26, 2021.03, [URL], This book addresses the design challenges in near-field wireless power transfer (WPT) systems, such as high efficiency, compact size, and long transmission range. It presents new low-profile designs for the TX/RX structures using different shapes of defected ground structures (DGS) like (H, semi-H, and spiral-strips DGS). Most near-field WPT systems depend on magnetic resonant coupling (MRC) using 3-D wire loops or helical antennas, which are often bulky. This, in turn, poses technical difficulties in their application in small electronic devices and biomedical implants. To obtain compact structures, printed spiral coils (PSCs) have recently emerged as a candidate for low-profile WPT systems. However, most of the MRC WPT systems that use PSCs have limitations in the maximum achievable efficiency due to the feeding method. Inductive feeding constrains the geometric dimensions of the main transmitting (TX)/receiving (RX) resonators, which do not achieve the maximum achievable unloaded quality factor. This book will be of interest to researchers and professionals working on WPT-related problems..
2. Sherif Hekal, Ahmed Allam, Adel Abdel-Rahman, Ramesh K. Pokharel , Compact Size Wireless Power Transfer Using Defected Ground Structures, Singapore, 10.1007/978-981-13-8047-1, 1-91, 2019.09, [URL], This book addresses the design challenges in near-field wireless power transfer (WPT) systems, such as high efficiency, compact size, and long transmission range. It presents new low-profile designs for the TX/RX structures using different shapes of defected ground structures (DGS) like (H, semi-H, and spiral-strips DGS). Most near-field WPT systems depend on magnetic resonant coupling (MRC) using 3-D wire loops or helical antennas, which are often bulky. This, in turn, poses technical difficulties in their application in small electronic devices and biomedical implants. To obtain compact structures, printed spiral coils (PSCs) have recently emerged as a candidate for low-profile WPT systems. However, most of the MRC WPT systems that use PSCs have limitations in the maximum achievable efficiency due to the feeding method. Inductive feeding constrains the geometric dimensions of the main transmitting (TX)/receiving (RX) resonators, which do not achieve the maximum achievable unloaded quality factor. This book will be of interest to researchers and professionals working on WPT-related problems..
3. Ramesh Kumar Pokharel, Adel Barakat, Innovative Techniques for 60 GHz On-Chip Antennas on CMOS
Substrate
, (In press), 2017.03, The 60 GHz band has a 7 GHz of bandwidth enabling high data rate wireless communication. Also, it has a short wavelength allowing for passive devices integration into a chip; i.e. fully integrated system-on-chip (SOC) is possible. This chapter features the design, implementation, and measurements of 60 GHz on-chip antennas (OCAs) on Complementary-Metal-Oxide-Semiconductor (CMOS) technology. OCAs are the primary barrier for the SOC solution due to their limited performance. This degraded performance comes from the low resistivity and the high permittivity of the CMOS substrate. We present here two innovative techniques to improve the CMOS OCAs’ performance. The first method utilizes Artificial Magnetic Conductors to shield the OCA electromagnetically from the CMOS substrate. The second methodology employs the PN-Junction properties to create a high resistivity layer. Both approaches target the mitigation of the losses of the CMOS substrate; hence, the radiation performance characteristics of the OCAs are enhanced..
4. Ramesh K. Pokahrel, H. Kanaya, and K. Yoshida, Microwave and Millimeterwave Technologies, Viena, Austria, ISBN 978-953-7619-X-X, IN-TECH Publications, 2010.1 (In Press)., 2010.01, [URL].

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