A reflective TWTA predistortion linearizer for Ka-band application

Abstract

A predistortion linearizer used for Ka-band travelling wave tube amplifiers (TWTAs) was proposed. Based on analysis of nonlinear transfer characteristics of TWTA using a power series, the inverse nonlinear distortion characteristics of predistorter which was also the model of predistortion linearizer was proposed. A reflective structure was used to realize the linearizer, it's composed of anti-parallel schottky diodes, quadrature hybrid, matching networks seen from the diodes. The Carrier-to-Intermodulation(C/I) of Kaband TWTA was improved a maximum of 19dB by proposed predistortion linearizer.