Improved Ultrawideband Rectennas Using Hybrid Resistance Compression Technique

Abstract

This communication presents a novel hybrid resistance compression technique (HRCT) to improve the performance of broadband rectennas. The HRCT can offer resistance compression characteristic by reducing the nonlinear effects of the rectifier and provide improved impedance matching performance over a wide frequency range. Two ultrawideband rectennas (with/without using the HRCT) have been designed, made, and tested. The proposed rectennas have a very wide bandwidth from 450 to 900 MHz (covers the entire DTV, LTE700, and GSM900 bands in the U.K.) with relatively high conversion efficiency (up to 77%). The HRCT can maintain the high efficiency of the rectenna in a wide load impedance range (from 5 to 80 $\text{k}\Omega )$ . The measured harvested dc power of the rectenna from an outdoor ambient environment is about 66.7 $\mu \text{W}$ with an overall conversion efficiency of 42.2%, which is therefore suitable for wireless energy harvesting to power low power electronic devices with different load impedance.