High efficient C-band circularly polarized rectenna array with low-profile and lightweight

A high efficient C-band circularly polarized rectenna array with low-profile and lightweight for wireless power transmission of space solar power stations is proposed and designed in this paper. The receiving antenna is an aperture-coupled microstrip quasi-square patch. The patch simultaneously excites two orthogonal modes of TM₁₀ and TM₀₁, which have a phase difference of 90° by the perturbation method, so that the antenna operates in a circularly polarized state. The rectifier circuit is designed by microstrip lines in a parallel topology, and it consists of a stepped impedance matching network, a Schottky diode, two sector-branches as pass-through filter and a load. The input impedance of the rectifier and the characteristic impedance of the antenna feedline are both 50 $\Omega$ for being directly integrated into a rectenna. This rectenna has the advantages of low profile and scalability. The rectenna element, 3 × 3 and 4 × 4 subarrays are simulated and tested with good agreement being obtained. The measured results show that the rectification efficiencies of the element and the two subarrays are 73.1%, 72.7%, and 71.3% respectively at the center frequency of 5.76 GHz. Finally, a large rectenna array with 0.7 m aperture is designed to verify the scalability of the design. It will obtain 16.7 W of DC power at an efficiency of 65%. The rectenna has a profile of 1.61 mm and a surface density of less than 1.2 kg/m².