A Novel High-Gain Rectenna for Wireless Power Transmission (WPT) Applications

This work reports a novel high-gain rectifying antenna designed for wireless power transfer applications. Initially, a novel compact butterfly dipole antenna was developed and optimized for the UMTS-2100/3G and GSM-1800/4G frequency bands. A band-stop reflector based on a frequency selective surface (FSS) structure is designed and integrated with the antenna to enhance its radiation characteristics over the desired bandwidth. A high-efficiency rectifying circuit is developed to operate over a broad input power range within the desired bandwidth. The antenna's measured results showed a significant enhancement in its gain and reflection coefficient after integrating the FSS reflector. At the desired frequencies of 1.8 and 2.1 GHz, the gain reached 8.59 and 6.69 dBi, increasing by 6.41 and 3.71 dBi, respectively. The reflection coefficient achieved a peak value of −44.19 dB at the resonant frequency of 1.86 GHz, improving by 25.49 dB compared with the antenna without a reflector. The bandwidth also expanded by 0.09 GHz to reach 0.45 GHz, from 1.71 to 2.16 GHz, and the fractional bandwidth (FBW) is 23.26%. The rectifier's measured results showed high conversion efficiency, achieving 63.2% and 57.4% at the desired frequencies of 1.8 and 2.1 GHz, respectively, for an input power level of 10 dBm. In addition, it provides more than 50% conversion efficiency across a wide input power range of 16.5 dBm (−0.1 to 16.4) and 11.7 dBm (2.8–14.5) at frequencies 1.8 and 2.1 GHz, respectively.