A New Envelope Predistorter With Envelope Delay Taps for Memory Effect Compensation

We present a new linearization method for high-power amplifiers, using an envelope predistorter (EPD) including envelope delay taps and control circuits, for memory effect compensation. The lower and upper third-order intermodulation (IM3) components, generated by the EPD, can be separately controlled for their magnitudes and phases by the additional memory effect compensation circuits. By using experimental results for a high-power (30-W peak envelope power) class-AB amplifier, further linearity improvement was also demonstrated using the proposed EPD. For a two-tone signal with a tone spacing of 20 MHz, the proposed EPD, with only a single delay tap, cancelled the lower and upper IM3components by 20.84 and 18.17 dB, while the conventional EPD, with no envelope delay tap, cancelled them by 11.67 and 8.50 dB, respectively