A Low-Profile Compact Broadband CP DRA for RF Energy Harvesting Applications

In this letter, a low-profile circularly polarized (CP) chamfered rectangular dielectric resonator antenna (RDRA) is designed and investigated for radio frequency energy harvesting (RFEH) applications. The proposed modified RDRA comprises of dielectric resonator (DR) made up of Alumina material (& epsilon;(r) = 9.9) mounted on the PEC ground plane. Dual unequal triangular-shaped vertical slits are engraved on the rectangular DR for generating the orthogonal modes with CP characteristics. The optimized antenna offers an impedance bandwidth (IBW) of 51.4% (2.25-3.81 GHz) and axial ratio bandwidth (ARBW) of 14.8% (3.25-3.77 GHz), respectively. The peak realized gain and maximum radiation efficiency are 7.18 dBi and 97.8% in desired frequency bands. Due to the wide impedance and AR bandwidths with realized gain and radiation efficiency, the optimized antenna is suitable for integration with a rectifier circuit for RF energy harvesting applications. A rectifier circuit with a single shunt diode topology is also designed for rectification purposes. The rectifier achieved 67.16% RF-DC power conversion efficiency (PCE) at 3.5 GHz and 5dBm input power. At 0dBm input power, the rectifier achieved 60.26% PCE. The effective input power range, during which the PCE maintains above 50%, is calculated to be 15.2 dBm from -3.5 to 11.7 dBm.