EVEN HARMONIC RESONANT CLASS-E TUNED POWER-AMPLIFIER WITHOUT RF CHOKE

A method for designing an amplifier that does not need an RF choke coi l is proposed. This is accomplished by adding a shunt capacitor to a c lass E amplifier with a shunt inductor; this creates class E switching where higher harmonics are induced in the inductor-fed input waveform . A design method is derived by performing an analysis of the circuit assuming load current is sinusoidal. Because the switch current is sma ller than that of conventional class E amplifiers (with the same outpu t power), the losses due to the series saturation resistance of the sw itch device are greatly reduced for the proposed amplifier. A 96-perce nt RF conversion efficiency for 2 W of output power was obtained in ex periments using a 2-MHz switch using the proposed design.