A Broadband Class-E Parallel-circuit VHF Power Amplifier with High Harmonic Suppression

摘要

High harmonic suppression while maintaining a class-E condition for a broad frequency range is achieved with a new type of load network circuitry. A broadband parallel-circuit class-E network, cascaded with a series L_xC_x and a high-Q roll-off elliptical harmonic filter was used for this implementation. The novel L_x G_x circuit compensates the large reactance variation of the elliptical harmonic filter, which enables class-E PA operation. An efficiency of 70 percent and a second-harmonic suppression of -73 dBc was measured across a wide bandwidth (135 to 175 MHz) with an operating power of 6.5 W. The efficiency and harmonic results are the highest reported so far at VHF frequencies with a 40 MHz bandwidth and a supply voltage of 7.2 V.