A Wide Dynamic Range Rectifier Based on HEMT With a Variable Self-Bias Voltage.

This brief focuses on a highly efficient rectifier based on a high-electron-mobility transistor (HEMT) with a wide dynamic range of input power. Due to the nonlinear characteristics of HEMT, the impedance mismatch at different input power levels is a major challenge in rectifier design. Herein, a variable voltage gate self-bias network is proposed. It can dynamically generate a DC voltage according to the input power level, and continuously provide the optimal bias for the HEMT, thereby improving the RF to DC conversion efficiency in a wide input power range. This design does not require any external sensing or dynamic control circuit. The power needed by the self-bias network is provided using a weak coupling structure placed at the input port, which couples a small amount of the received RF power to operate the self-bias network. It is demonstrated that the proposed rectifier can achieve a dynamic operating power range of 24 dB (from 1 to 25 dBm) for over 60% conversion efficiency, or 16 dB for over 70% conversion efficiency in the measurement.