Design of a GaN HEMT power amplifier using resistive loaded harmonic tuning

The proper termination of the 2^nd harmonic impedance is the basic task during the design of a harmonically tuned power amplifier. In addition to several approaches of defining fundamental and harmonic pairs with purely reactive harmonics, the harmonic components can be terminated resistive as well. This work presents a broadband GaN HEMT power amplifier with resistive 2^nd harmonic termination. The measured output power of 41.1 to 42.6 dBm was achieved covering a frequency range from 2.2 to 2.7 GHz. The drain efficiency of the amplifier ranged from 66.2 to 75.2 percent. Applying a LTE signal with 10 MHz bandwidth, a linearized average efficiency of 42 % was attained.