An E-pHEMT self-biased and self-synchronous class E rectifier

In this paper, the design of a self-biased and self-synchronous class E rectifier, based on an Enhancement-mode Pseudomorphic High Electron Mobility Transistor (E-pHEMT), is proposed. Characterized by a small value of the switch-mode time-constant (the on-state resistance times the output capacitance), high power efficiency figures may be obtained when forcing zero-voltage and zero-voltage-derivative switching conditions (ZVS and ZVDS). The self-synchronous operation, made possible by the device gate-to-drain coupling capacitance, leads to a compact design, while the gate-to-source Schottky junction allows self-biasing the gate terminal in order to improve the efficiency versus input power profile. Simulations, based on an extracted simplified non-linear model, are combined with measured results for implementations at 900 MHz and 2.45 GHz. Efficiency values as high as 76% and 64% have been estimated at power levels of -4 dBm and -1 dBm, respectively, with peak figures of 88% and 77%.