A dual-frequency rectifier with adaptive power

Abstract

A dual-frequency rectifier with adaptive power is proposed for the rectenna of a microwave power transmission system. It operates at 900MHz and 2.4GHz (GSM and ISM bands) on a wide and low input power condition. A FET works as an adaptive switch for changing the working modes of the rectifier according to the level of the input power. A cross-shaped match stub matches the two impedances of the diode to 50fl. A shunted capacitor works as a dc-pass filter to smooth the output DC power. The simulated maximum conversion efficiencies at two operation frequencies are 63.5% and 56.9%, respectively. The input power range in which the efficiency exceeds 40% is from -16dBm to 4dBm at 900MHz and is from -13dBm to 5dBm at 2.4GHz.