Highly linear and efficient unsymmetrical inverted Doherty power amplifier employing phase compensation

This paper reports highly linear and efficient unsymmetrical inverted Doherty power amplifier (IDPA) employing the phase compensation. By inserting additional offset lines at the input path of the carrier cell, the phase variation between the carrier and peaking paths is compensated. For verifications, the unsymmetrical IDPA is implemented with 30-W Si LDMOSFETs and tested using a continuous wave (CW) and a one-carrier wideband code division multiple access (WCDMA) signals at 2.14 GHz. For a CW signal, by inserting additional input offset lines at the carrier cell path, the results of the output power, gain, and the drain efficiency at the saturation region increase slightly. For a one-carrier WCDMA signal, the drain efficiency of 27.9 % is achieved and the adjacent channel leakage ratios (ACLRs) at ±5-MHz offsets are below -47 dBc at a 10-dB back-off power (BOP). After the DPD linearization, the ACLRs of below -57 dBc at ±5-MHz offsets are obtained.