Continuous Current Mode Class-F Power Amplifier: A Solution for Bandwidth Extension in Low Breakdown Voltage Applications

This paper introduces a theoretical analysis and experimental validation of a Continuous Current Mode (CCM) class-F power amplifier. The proposed CCM addresses the soft breakdown drain-source voltage limitations encountered in conventional continuous class-F mode power amplifiers when they are implemented in low breakdown voltage technologies like GaAs-MESFETs and GaAs-PHEMTs. The CCM class-F power amplifier preserves the high-efficiency and power characteristics of class-F power amplifiers. Through theoretical analysis and experimental validation, we demonstrate that this amplifier mode effectively broadens the design space, enabling extended bandwidth operation with efficiency and power relatively constant. Experimental results obtained by using a time-domain low-frequency harmonic active load-pull system (LF-AHLP) validate the theoretical framework, alleviating the soft breakdown drain-source voltage recently observed in continuous class-F power amplifiers.