60 GHz MIMO Transceiver Design for Base Station of Radio over Fiber System

Abstract

A MIMO system for 60 GHz wireless communication based on Radio-over-Fiber (RoF) technique is designed and discussed. In this paper, a $2 \times 2$ antenna array on 300 micron quartz (Silica) substrate with a bandwidth of 6 GHz for operating in V-band (50 GHz-75 GHz) is designed. The achieved gain is 9 dB. Moreover, a novel wideband planar bias tee (BT) circuit with a quarter-wave coupled-line is designed on the same substrate. It will provide proper biasing for millimeter wave photodiodes through the RF-choke and isolates the antenna from the bias. Simulation results show that the return loss is below 15 dB for the entire 45 GHz to 75 GHz band and it reaches to 45 dB at 60 GHz, while the insertion loss is lower than 0.5 dB. The overall performance of the complete antenna and BT circuit has been calculated by the 3D full-wave electromagnetic field simulator CST.