Design of a GaN HEMT Power Amplifier Using Output Matching Circuit with Arbitrary Harmonic Impedances

In this paper, a design of a GaN HEMT power amplifier using output matching circuit with arbitrary harmonic impedances is presented. The adopted GaN HEMT device, TGF2023-02 of TriQuint Semiconductor, was packaged in commercial package. The optimal impedances of the GaN HEMT package are extracted from load-pull simulation at package input and output reference planes. The targets of load-pull simulation are the highest output power at fundamental frequency and the highest efficiency at and harmonic frequencies. Because of fixture in the package, the extracted impedances shows arbitrary harmonic impedances. In order to match the optimal impedances, output matchin circuit which has 4 transmission lines is presented. Characteristic impedances and electrical lengths of the transmission lines are mathmatically calculated. The power amplfiier with shows the output power of 8 W at the fundamental frequency of 2.5 GHz, the efficiency above 55 %, and harmonic suppression of above 35 dBc at the and the harmonics.