An integrated harmonic transmitter front-end for 122 GHz FMCW/CW radar sensor

This paper presents an integrated harmonic transmitter front-end for a single-chip 122 GHz FMCW/CW radar sensor. It consists of two building blocks, a frequency doubler and a two-directional power detector. The frequency doubler employs a push-push frequency doubling core and a common-base stage. It exhibits a 2.5 dB conversion gain and a 5 dBm output power. The two-directional power detector is used for self testing, which utilizes a single directional coupler to save chip area and to reduce insertion loss. It can detect the output power of the transmitter and can detect any antenna mismatch of above -20 dB. This transmitter front-end can be fully characterized by DC measurement after integrated into a single-chip 122 GHz transceiver.