A linear GaN power amplifier using novel transistor based analog predistortion method

This paper presents a novel transistor based analog predistortion method and its application in designing a linear GaN power amplifier (PA). The proposed analog predistorter (APD) can improve the third-order intermodulation distortion (IMD3) over the whole output frequency offset range. Furthermore, this structure can evidently simplify circuits design due to no vector modulator is involved. To demonstrate the new methodology, a 10W GaN power amplifier based on the proposed APD is implemented and tested at 2.4 GHz. The simulated results of the GaN PA with proposed APD shows that significant IMD3 improvement of better than 10 dB is achieved and the output 1dB gain compression point (P1dB) is increased from 35 dBm to 38.5 dBm under the measurement with two-tone drive signals.