Concepción de amplificadores de potencia microondas de alto rendimiento

Abstract

In this paper, we present the design of a high efficiency class-F power amplifier in pHEMT technology using an accurate WREN/COBRA model at 2GHz. The transistor is overdriven into compression in order to maximize efficiency and output power. Three concepts of output matching networks are used in the design of class F power amplifiers, based on harmonics output terminations, that is shown to have a critical influence on PA performances when compared to a classical class B power amplifier (PAE= 61.56%, Pout=12.14 dBm). The design of the first amplifier is based on 2nd harmonic termination while all other harmonics are open circuited where the output is seen to consist of a half-wave rectified voltage waveform. 87.37% saturated PAE and 12 dBm output power are obtained for this amplifier. In the second amplifier, the 3th harmonic is terminated and the output is seen to consist of a square wave voltage waveform. This amplifier result in 72.87% saturated PAE and 12.52 dBm output power. Finally, following a detailed theoretical analysis, a class F matching network that suppress the necessary load harmonics, is used for the design of the third amplifier. The saturated PAE delivered is 74.19%, the output power is 12 dBm and a square wave voltage waveform is obtained at the output.