A Ku-band 70-W Class GaN Internally Matched High Power Amplifier with Wide Offset Frequencies of up to 400 MHz for Multi-Carrier Satellite Communications

This paper describes a Ku-band 70-W class GaN internally matched high power amplifier (HPA) with wide offset frequencies of up to 400 MHz for multi-carrier satellite communications. Our proposed output matching circuit uses three different kinds of difference-frequency short-circuits for realizing the wide offset frequency operation; two of the three are embedded into a tournament-shaped output matching circuit inside the HPA package and the rest is embedded into the drain bias feed placed outside the package. In order to verify the short-circuit design and its effectiveness, the Ku-band GaN HPA was designed, fabricated, and measured. The measurement shows that the HPA achieves a peak output power of 48.6 dBm while keeping a linear output power of over 40 dBm and -26-dBc IMD3 over wide offset frequencies of up to 400 MHz. To the authors' knowledge, this HPA has the record linearity of the 400-MHz wide offset frequencies and low IMD3 of less than -25 dBc among the ever reported Ku-band GaN HPAs for multi-carrier satellite communications.