A varactor diode based predistortion circuit

Operation and performance of a varactor diode based linearizer is investigated. This novel predistortion topology employs a series resonant circuit with a reverse biased varactor diode acting as a power dependant capacitor. The linearizer itself is both simulated and tested to display its nonlinear properties. In addition, a 1.8 GHz power amplifier is linearized based on this technique. An improvement of 11 dB in ACPR and an increase in 1.8 dB for the compression point is measured for the linearized PA.