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.