Ka-Band Power Amplifier Design for Radar Transmitter Using 40-nm CMOS Process

This paper presents a power amplifier for synthetic aperture radar transmitters using the Ka-band and a 40-nm CMOS process. The designed amplifier consists of two stages: A driver amplifier in the first stage and a power amplifier in the second stage. The driver amplifier employs a differential common-source amplifier, whereas the power amplifier is designed using a differential cascode amplifier. To ensure the stability of the amplifiers, both the driver and power amplifiers utilize neutralization techniques that utilize capacitors. The input of the driver amplifier was matched using a single-to-differential balun, whereas interstage matching between amplifiers was achieved using transformers. The power amplifier output is matched for power optimization using a differential-to-single balun. The output power of the power amplifier is 16.9 dBm, consuming 351 mW of power. The center frequency of output power is 34 GHz, with a 1 dB bandwidth ranging from 28.1 to 39.8 GHz. The total area, including the DC and input/output pads, was 711 μm×504 μm.