5W, 0.35–8 GHz linear power amplifier using GaN HEMT

In this paper, a 0.35-8 GHz, 5 W, linear power amplifier based on GaN HEMT die is reported. Load pull characterization was used to optimize the power performance in the operating bandwidth. 3D-EM simulations were also performed to model the coaxial 50 Ohm connections, bond wires and matching networks resulting in an excellent agreement between simulations and measurements. Regarding the performance, the designed single stage PA has exhibited 9 ± 1 dB gain, an output power (Pout) of greater than 37 dBm (5 W), worst power added efficiency (PAE) of 20% over a multi-octave (0.35-8 GHz) bandwidth. The PA has been also fully characterized from the linearity point of view based on single-tone (AM/AM, AM/PM) and two-tone techniques (with 100 kHz frequency spacing). An AM/AM and AM/PM distortions of only ± 0.5 [dB/dB] and ± 2 [dB/deg] at 8 GHz have been observed. As a measure of linearity in two-tone performance an output third-and second- order intercept points (OIP3, OIP2) have been extracted over the whole bandwidth. An OIP3 of ≥ 49 dBm and OIP2 of ≥ 67 dBm can be achieved.