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MOSFET Based Absorber for Reflected Signal in 5G Massive MIMO Base Station - A Circuit Perspective

Elliot O. Omoru and Viranjay M. Srivastava
Department of Electronic Engineering, Howard College, University of KwaZulu-Natal, Durban-4041, South Africa

Abstract—A lossy transmission has negative effect on the overall performance and efficiency of base station subsystems. One key feature of 5G technologies is improved efficiency compared to 4G technology. The 5G massive-MIMO base station structure may suffer from these losses, which affect the inclusive performance and efficiency of the base substation. Furthermore, in the 5G technology, loss is anticipated due to the reflection of signals from the receiver (Rx) branch connected to the circulators in the 5G MIMO base station. This reflection loss is due to the mismatched load impedance of the Rx branch with the source impedance of transmitter (Tx) branch. The main objective of this research is to use MOSFET to absorb the reflected signal resulting from impedance mismatching between the Tx and Rx. After that, two comparisons have been made between source current and drain current of the MOSFET mathematically, whenever there is a reflection from the Rx branch of the base station. In addition, the proposed circuit model has been presented by connecting the Tx branch, antenna, Rx branch, and the MOSFET to each of the ports of a four-port circulator. A reflected RF power of 13 dBm at 1.4 V peak is rectified to its equivalent DC value 1.004 V. However, these values of current and voltage are pulsating and filtered at the output end of the rectifier with the use of an LC Filter.

Index Terms—Base station, circulator, MOSFET, transceiver, microwave device, nanotechnology, 5G, VLSI

Cite: Elliot O. Omoru and Viranjay M. Srivastava, "MOSFET Based Absorber for Reflected Signal in 5G Massive MIMO Base Station - A Circuit Perspective," Journal of Communications vol. 15, no. 11, pp. 833-840, November 2020. Doi: 10.12720/jcm.15.11.833-840

Copyright © 2020 by the authors. This is an open access article distributed under the Creative Commons Attribution License (CC BY-NC-ND 4.0), which permits use, distribution and reproduction in any medium, provided that the article is properly cited, the use is non-commercial and no modifications or adaptations are made.