Microwave watt-level rectifiers for power recycling applications

This work reports on a 2 W microwave diode rectifier for power recycling applications. We characterize the rectifier over a large input power range and for two different loads, a resistive and a dc load. We show that for the dc load used in power recycling applications, the large power variation that is common in such applications causes a significant degradation in efficiency owing to the strong dependence of the rectifier input impedance on input power. This is in contrast to the relatively weak impedance change for low power and resistive loads encountered in energy harvesting applications. We designed and tested 2 W 4.1-4.6 GHz harmonically tuned rectifier that achieves a peak efficiency of 61% at 1 W of input power.