Investigation of PCB microstrip patch receiving antenna for outdoor RF energy harvesting in wireless sensor networks

In this paper, the suitability of using a printed circuit board (PCB) microstrip patch receiving antenna for a novel application - RF energy harvesting to power a wireless soil sensor network deployed in an outdoor environment - is investigated. The performance of a conventional circular microstrip patch antenna using different microwave laminate substrates is evaluated in terms of return loss, radiation efficiency, and gain. Based on a chosen PCB material as the antenna substrate, an enhanced gain circular patch with a ring shaped parasitic radiator is presented. Simulations have been carried out using CST microwave studio to examine the antenna's performance both in free air and in the presence of different soil conditions.