High-Efficiency Broadband Class-E PAs for More Than One Octave: Analysis and Design

This article presents a solution based on continuous mode for designing broadband class-E power amplifiers (PAs), which is realized by transmission of the second-harmonic current with appropriate phase to load network of a class-E PAs. This theory allows selecting appropriate second-harmonic impedance causing part of efficiency to be sacrificed to get a bandwidth over one octave. The mathematical formulation for optimum load impedance in main harmonic, second harmonic, output power, drain efficiency (DE), and load quality factor (QL) is developed in this case. Theoretical results are compared with conventional narrowband class-E counterparts. To check the authentication of mathematical analysis and simulation results, a proof-of-concept broadband continuous-mode class-E PAs is fabricated using the CGH40025F transistor. The manufactured PAs show 43-dBm output power, with average DE 70% over the 0.6-1.8-GHz frequency range. Also, a narrowband conventional class-E PA for frequency range 1.2-1.8 GHz with the same transistor as broadband class-E PA is fabricated for better comparison. The output power and average DE of the conventional class-E PA are 42.5 dBm and 80%, respectively.