Novel Compact Transmission-line Output Network Topology for Class-E Power Amplifiers

This paper presents a new low-complexity transmission-line load transformation network topology suitable to synthesis class-E impedance termination with a minimum of circuit elements. Only one additional stub, besides the quarter wavelength drain bias stub, is used to control simultaneously fundamental, second and third harmonic frequency impedance termination. In this way, loss in the load coupling network is minimised resulting in higher efficiency than by using other approaches. Design and performance of a highly efficient class-E power amplifier operating at 1 GHz based on the proposed transmission-line output network topology are presented. State-of-the-art power added efficiency of 80% at 1 GHz for an output power of 7 W is measured.