A Current-Injection Class-E Power Amplifier

A novel class-E power amplifier (PA) using a current-injection (CI) technique is presented in this letter. An auxiliary current source, which injects the current into the load during each turn-off period of switching transistors, is introduced into the conventional class-E PA. Without the need of impedance transforming or increasing of the supply voltage, the proposed PA provides a new method to increase the output power. The proposed circuit is fabricated in a Taiwan Semiconductor Manufacturing Company's (TSMC's) 65-nm low power (LP) CMOS process. Measurement results show that the output power of the injected circuit reaches up to 14.12 dBm with a drain efficiency of 41% at 1.8 GHz. The output power improves more than 3 dB compared to the conventional class-E PA without CI.