Linearity‐optimized GaN HEMT Doherty amplifiers using derivative superposition technique for WCDMA applications

Gallium nitride (GaN) high‐electron mobility transistor (HEMT) Doherty amplifiers with the optimized linearity for wide‐band code division multiple access (WCDMA) applications are represented. At a 7‐dB back‐off output power, the measured single‐carrier WCDMA results show two‐way and three‐way GaN HEMT Doherty amplifiers with an adjacent channel leakage ratio (ACLR) of −43.2 and −48.2 dBc at ±2.5 MHz offset frequency with a drain efficiency of 43.1% and 30.9%, respectively.