Resonant-Linear Hybrid Structure for Power Amplifier at Radio Frequency Band

This article presents a novel resonant-linear hybrid converter for a radio frequency (RF) power amplifier (PA). The proposed topology consists of a push-pull resonant inverter and a voltage-controlled linear amplifier at the output port. The push-pull resonant inverter consists of two single-ended Class Φ2 inverters, and the voltage-controlled linear amplifier controls the output voltage to track the phase of the reference voltage for phase control of the output. Thus, the output voltage can be well controlled as a pure sinusoidal curve. A driving circuit is presented in this article to make the output current of the push-pull resonant inverter in phase with the linear amplifier. Moreover, a quasi-trapezoidal voltage output driving circuit is designed to decrease the drive losses, and a multiresonant network with a 180° phase shift is also presented in this article to produce a sinusoidal driving voltage to avoid the shoot-through problem. This structure serves the 100 MHz RF band, In future, this hybrid structure could be applied in the transmitter of microwave power transmission (MPT) system. Finally, a 100 MHz/20 W prototype was built to verify the theoretical analysis.