A compact Ka-band MMIC power amplifier using continuous Class-B/J mode technique

This letter presents a Ka-band GaAs broadband high efficiency power amplifier (PA). The power amplifier achieves the best trade-off among gain, output power, power added efficiency (PAE), and fractional bandwidth through nonlinear simulations to select proper device size and bias conditions. The high-efficiency and broadband performances are achieved by using continuous Class-B/J mode for fundamental and second harmonics output matching network. The fabricated PA achieves a power gain of 18.8 dB, a 3-dB bandwidth of 25–30.2 GHz, a saturation power 25.5 dBm, a peak PAE of 30.0%. The chip size is as compact as 1.08 mm² including all pads.