Predistortion Linearizer for Wideband AM/PM Cancelation With Left-Handed Delay Line

In this letter, a modified predistortion linearizer model is proposed to enable wideband synthesis of phase predistortion function. Additional time delay based on an artificial left-handed transmission line is introduced in the model to characterize the frequency-dependent phase conversion function, which can be utilized for wideband cancelation of the AM/PM distortion in microwave power amplifiers. Based on the proposed model, a microwave monolithic integrated circuit predistorter is designed to generate both positive gain and phase conversion according to the input power, and to realize increasing phase conversion as frequency increases. Large signal measurement of the design is performed at 20, 20.75, and 21.5 GHz. Result shows that +4.8-dB gain conversion is achieved, while phase conversion increases from +12.9° to +30.8° as frequency increases from 20 to 21.5 GHz.