V-Band Crosslink Solid-State Power Amplifiers

An efficient High-Power Amplifier covering the 59-65 GHz communications band is proposed. The required power and linearity goals are accompanied by challenging efficiency goals. Current GaN and GaAs Monolithic Microwave Integrated Circuits (MMICs) are designed primarily for highest power operation well into compression where they are severely nonlinear. Backing off the power into the linear region severely reduces the efficiency. Many MMICs need to be combined, with attendant gain and phase misalignments, to generate the desired rf power. We propose to: 1.) develop GaN power MMICs optimized for linearity and efficiency – lower voltage, intermodulation and efficiency contours; 2.) Low-loss waveguide radial combiner; 3.) MMIC-level pre-distortion linearizer with 3 dB improvement in distortion internal to MMIC; 4.) MMIC-level gain-phase trim cell – MMIC and assembly alignment. The MMIC circuitry approaches will include transconductance derivative superposition, push-pull with internal balun, and in-phase combining. The radial combiner approach offers lowest loss coupled with minimal size and graceful degradation. The on-chip linearizer and gain-phase trim cells allow individual Linearization and gain-phase alignment at all levels of assembly and post-assembly of the power modules and radial combiner. The technology will have a path to Space-Qualification.