UHF and X-Band Class-E amplifiers

Citation

Li, Shijie (1999) UHF and X-Band Class-E amplifiers. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/wrwt-7a21. https://resolver.caltech.edu/CaltechETD:etd-02082008-163454

Abstract

A Class-E amplifier consists of a single transistor which is driven as a switch and a passive output load network. The output load network is a tuned resonant circuit and is designed to minimize the voltage and current waveforms overlapping, thus minimize the power dissipation in the transistor. The Class-E amplifier is for high efficiency operation with a theoretical maximum efficiency of 100%, and in practice about 80%-90%. Design approaches for Class-E amplifiers are described. Designs and experimental results for one 440 MHz and two X-band Class-E amplifiers are presented in detail. The 440 MHz Class-E amplifier is implemented using lumped components and the active transistor is the Motorola MRF183 n-channel lateral MOSFET. It delivers an output power of 15 W, drain efficiency of 77%, power-added efficiency (PAE) of 70% with an input power of 1.4 W. For the two X-band Class-E amplifiers, one uses Fujitsu FHX35X HEMT as the active device and has an output power of 30 mW, drain efficiency of 80% and PAE of t 11.2 GHz. The other one uses Fujitsu FLR056XV MESFET and achieves an output power of 190 mW, drain efficiency of 72% and PAE of 56% at 9 GHz. The two X-band Class-E amplifiers are implemented using microstrip transmission lines.

Thesis Files