Investigation of the Effect of Phase Offset on GaN Transistor-Based Rectifiers and Its Application in Broadband Designs

This paper analyzes the effect of phase offset on transistor-based class-F, class-B/J, class-F-1 self-synchronous rectifiers. The relationship between rectification efficiency and phase shift is theoretically built for the first time, and the rectification efficiency under different phase offset conditions is obtained. By choosing appropriate phase offsets and continuous mode parameters, the high rectification efficiency can be obtained. Meanwhile the available impedance space is significantly expanded. Combination of the extended impedance space and the variable phase shift provides a novel approach for the design of broadband high-efficiency rectifiers. In addition, the frequency mapping methodology is proposed to satisfy this impedance space and phase shift range. For validation, a broadband high-efficiency class-F rectifier based on a GaN transistor is designed, fabricated, and tested. Experimental results demonstrate that the rectification efficiency of between 65.4% and 87.2% is realized in the frequency range of 1.6-3.0 GHz when the dc load <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R_{\mathrm { dc}}=80~\Omega $ </tex-math></inline-formula> and the input power <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\mathrm { in}}=40$ </tex-math></inline-formula> dBm. The proposed rectifier has the widest operation bandwidth among traditional transistor-based rectifiers.