High-Gain Circularly Polarized Antenna Array for Full Incident Angle Coverage in RF Energy Harvesting

Abstract

In this paper, a high-gain circularly polarized (CP) hexagonal antenna array is proposed for RF energyharvesting applications. The hexagonal antenna array is intended to operate at the frequency of 5.8 GHz. It is composed of 6 multilayer substrate CP antennas excited by an X-shaped aperture-coupling feed structure. A frequency selective surface (FSS) was added to further improve the gain, resulting in a maximum gain of 12.7 dBi per element. The main advantage of the proposed hexagonal antenna array is the ability to cover 360 degrees in the azimuth plane with a high gain in all directions without the use of any additional circuitry, allowing the effective absorption of ambient RF energy. A prototype was fabricated and measured, and a good agreement with the simulation results is achieved. In addition, a rectifier is used to convert RF energy absorbed by the antenna into DC energy at the frequency of 5.8 GHz. The measured RF-to-DC conversion efficiency of 44.5% and a DC output voltage of 423 mV at −10 dBm are observed. The performance of the rectenna array with one and six rectifiers has been demonstrated. With the use of a DC combiner, the total RF to DC efficiency of the array is 67.75%, with a DC output voltage of 1.115 V from −10 dBm has been recorded. Due to the immunity to misalignment of the CP antenna, the proposed rectenna array is very suitable for wireless power transfer (WPT).INDEX TERMS RF energy harvesting, High gain, Antenna array, Full angle coverage.

Performance Analysis of Wireless Communications with Nonlinear Energy Harvesting under Hardware Impairment and κ-μ Shadowed Fading

“…One of the emerging countermeasures is to harvest energy available in radio frequency (RF) signals surrounding communications devices. Presently, 5G/6G devices deploy successfully cheap energy harvesting (EH) integrated circuits [ 5 , 6 , 7 , 8 ]. Nonetheless, a plurality of performance analyses pertinent to RF EH has featured EH to be linear for simplicity [ 9 , 10 , 11 , 12 ].…”