A lumped-element analog predistorter for VHF application

An analog predistorter (APD) for VHF application is presented. The proposed predistorter is fully composed of lumped elements. It has a moderate memory compensation capability by using a lowpass filter, and also includes a compact IM3 generator which is capable of canceling the fundamental components. For verification, the proposed predistorter is implemented and applied to a RF power amplifier for 57.463.6MHz application with an average output power of 37dBm, the test results show that IMD3 of power amplifier improves more than 25dB for CW two-tone signal with a tone spacing of 1MHz, and significant improvement of IMD3 is obtained for two-tone signals with tone spacing varying from 5KHz to 3MHz.