Ultra linear C-band MMIC power amplifiers with 50dbm OIP3

Two 4W PA MMICs have been developed which cover bandwidths of 5.5-7.1GHz and 7.1-8.5GHz and which demonstrate OIP3 figures of 50dBm at up to 1W total two tone output power from a bias of 8V, 1300mA. The MMICs were fabricated using a highly linear 0.5um GaAs HFET process and packaged in a plastic molded 6mm QFN package. Interpolation of a comprehensive matrix of two tone load pull data was used to set the design target output and driver stage load impedances over bandwidth for the two stage design. The resulting ratio of OIP3 to P1dB is typically 16dB. A thermal design approach guided by finite element analysis and IR spectroscopy measurement was used. To the authors knowledge this is a significant improvement in OIP3 linearity over any other reported multi-stage MMIC amplifier operating at C band.