Analysis and modelling of a novel compact rectenna for indoor applications

Rectenna can be used for remotely charging the rechargeable batteries, commonly used for powering wireless sensors in buildings, with the help of a dedicated RF source. However, in such a process, the effective path loss reduces the RF power level on rectenna which lowers the RF-to-DC conversion efficiency of the system. This study therefore focuses on the design and analysis of an efficient integrated rectifier-antenna (rectennas) for indoor applications. In this proposed study, first a pentagonal antenna is designed at 5 GHz using Ansoft HFSS simulation. The obtained results show that the antenna resonates at two more frequencies, 10.7 and 14.2 GHz, other than the designed frequency. In order to eliminate the signals received by the antenna at these frequencies, a low-pass filter cornered around 5 GHz is designed and integrated with the antenna. As a result, the integrated structure reveals a return loss of around 15 dB at 5 GHz. Next for rectification purpose, a Schottky diode is characterised at 5 GHz. The proposed antenna structure is then matched to the optimal complex impedance of the diode circuit. Consequently the RF-DC conversion efficiency of the rectenna is found to be 46%.