Capacitive coupled circular patch antenna based rectenna systems for 5.8 GHz wireless power transfer applications

摘要

This paper, a two- and four-element linear array of capacitively coupledmicrostrip patch antenna have been presented for 5.8 GHz wireless powertransfer application. Initially, a 5.8 GHz matched rectifier has beendesigned that produces maximum 1.54 V output voltage across a 1.8 kΩload for 4 dBm input power. The maximum calculated efficiency is found tobe 52.70%. The rectifier was then connected with a spurious free antenna toform a rectenna, which provided 0.39 V output voltage across the load andmaximum 34.34% efficiency for received power of 0.246 mw. Since efficiencywas found low, next, an attempt has been made to increase theefficiency by increasing antenna gain. To do this, a two-element and a fourelementlinear array of the antenna have been formed and connected withthe rectifier to form the rectennas. To suppress spurious responses of arraysC-shaped slot etched on ground and U-shaped stub is placed at microstripfeed line. The two- and four-element array showed 11.4 dB and 15 dB gain,respectively, at 5.8 GHz (compared to 4.17 dB of the single elementantenna). Maximum output voltages and efficiencies of the rectenna formedusing two and four-element arrays are 0.83 V, 0.915 V and 45.06%, 52.55%respectively.