Improved Ultrawideband Rectennas Using Hybrid Resistance Compression Technique

This communication presents a novel hybrid resistance compression technique (HRCT) to improve the performance of broad-band 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 k Omega). The measured harvested dc power of the rectenna from an outdoor ambient environment is about 66.7 mu 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.