Stabilization of Class E amplifiers with a diode network

A three-element stabilization network consisting of diode and series resonant circuit to eliminate the instabilities seen in the Class E amplifiers for all load conditions when dc supply voltage is varied over entire dynamic power and frequency ranges, has been introduced. Diode in the stabilization network is used to linearize the varactor effect seen on the output capacitance of the transistor. It stabilizes the amplifier by having minimum impact on the amplifier parameters such as output power, efficiency, and die dissipation. Two-element series resonant network in the stabilization circuit bypasses diode at the fundamental frequency and provides normal operational condition for the amplifier. The stabilization network that we introduce is practical, cost effective and unlike other stabilization networks do not require multi-element filters, and significant adjustment on the load line of the amplifier. Class E push-pull amplifier with stabilization network has been designed, simulated, constructed and then verified experimentally. It is confirmed that the stability of the amplifier is gained across entire VSWR and dynamic ranges with the implementation of the stabilization network by meeting with all other amplifier requirements such as output power, efficiency, gain, etc.