In this paper, a 2 to 5 GHz (116% fractional bandwidth), highly linear power amplifier – based on GaN HEMT- with an output power excess of 10W is presented. The load pull technique is used to reach the optimum performance within the useful bandwidth. Electromagnetic simulations are carried out to model the matching networks on the substrate. The design is optimized based on the results of these electromagnetic simulations. Wideband matching, together with stability circuits are adopted to achieve a flat power gain of 7.7 ± 0.75 dB over the entire operating bandwidth, providing optimal fundamental and harmonic impedances within more than one octave of operation. The designed power amplifier exhibits a small signal gain more than 7.85 ± 0.75 dB, third-harmonic intermodulation distortion products (IMD3) far below -35 dBc at an input power of 29 dBm over the entire frequency band, and a power added efficiency (PAE) better than 15%. Using a two-tone test bench with a frequency spacing of 100KHz, a maximum value of the output OIP2 and OIP3 are found to
be greater than 55 dBm and 45 dBm, respectively.