A Circularly Polarized Rectenna Array Based on Substrate Integrated Waveguide Structure With Harmonic Suppression

A compact circularly polarized rectenna with harmonic suppression for wireless power transmission at 5.8 GHz is proposed in this letter. The substrate integrated waveguide structure is adopted for enhanced gain, unidirectional patterns, and surface wave suppression. A rectifier, which consists of a matching network, a diode, and a dc-pass filter, is integrated with the antenna at the back side. The proposed rectenna is fabricated and measured. It features 6.9 dB gain, 0.67 dB axial ratio, and 30 dB return loss. The conversion efficiency is 65.87% with a 700 Ω load. A rectenna array is also built for an increased aperture. It shows 61.49% conversion efficiency with 650 Ω load in measurement. Both the rectenna and array are satisfactory choices for wireless power transfer usage.