A Broadband Reflectarray Antenna for Microwave Power Transmission

In this work, a single-layer reflectarray antenna design operating at the center frequency of 5.8 GHz for microwave power transmission is proposed. The reflectarray unit embodies a slotted circular patch loaded with four symmetrical resonant phase delay lines. By adjusting the length of the phase delay lines, a reflection phase compensation range of about 400° is achieved. The reflectarray uses the low-cost F4B material as the substrate. The feed horn antenna adopts an offset angle of 15°, and the focal diameter ratio (F/D) is 1.2. Based on the reflectarray unit design, a 361-unit reflectarray antenna is designed with the desired pitch angle and azimuth of the reflected wave to be (0°, 0°). The measured gain is 27.3 dBi at the center frequency of 5.8 GHz. The aperture efficiency and 1 dB reflectarray bandwidth are 51% and 20.4% (5.01–6.15 GHz) respectively. In addition, at the center frequency of 5.8 GHz, the side-lobe level and cross-polarization level are lower than − 18 dB and − 30 dB, respectively.