Transformer-based 24 GHz Power Amplifier in 65nm CMOS Technology for FMCW Applications.

A 65nm CMOS power amplifier for frequency-modulated continuous-wave radar (FMCW) applications is presented in this paper. The PA stages are designed to enhance the power-added-efficiency given by the use case scenario of constant envelope in FMCW applications. Therefore, the output stage and the driving stage is implemented as differential pair with a transformer-based matching circuit, since low voltage devices are used, which limit the maximum output power. The output transformer has been designed for high power transfer and reaching an efficiency of 81%. The output stage has a gain of about 6dB and reaching a PAE of 45% at an output power of 13dBm.