Design and implementation of a circularly polarized rectenna for efficient RF energy harvesting

This paper presents a rectenna with a pentagonal-shaped circularly polarized (CP) antenna and a rectifier for radio frequency (RF) energy harvesting in the industrial, scientific and medical (ISM) (2.4 GHz) band. The antenna gain is increased by incorporating a frequency selective surface (FSS) over the patch of the antenna. A rectifier with a series topology and a T-matching network is used to translate RF energy received via the CP antenna to direct current power. The rectifier employs a Schottky diode (HSMS-2860) for rectification, achieving a peak conversion efficiency of 56.5% and delivering an output voltage of 238 mV at an input power of −10 dBm across a 1 kΩ load. Also, a unique 3D pentagonal array structure is presented, which consists of five FSS-based antenna elements, each with a 72° coverage angle. The 3D pentagonal antenna array allows for 360° collection of ambient signals, with the CP antenna sensing RF signals in the full azimuth plane, making it suitable for efficient RF energy harvesting.