A 120 GHz Transmitter for High Resolution Radar Application in 40 nm CMOS

This paper presents a highly integrated 120 GHz radar transmitter in a 40 nm CMOS process. The transmitter comprises a 60 GHz wide tuning range variable gain amplifier (VGA), a 60 GHz high resolution phase shifter (PS), a 60 GHz two-way power combining power amplifier (PA) and a 120 GHz frequency doubler. By utilizing multi-layer tapered connection and ground wall decoupling techniques in transistor layout design, the conversion loss of the doubler is effectively reduced. Distributed active transformer is employed to perform impedance matching and power combining of the PA. Benefiting from the techniques used, the transmitter chip achieves a measured peak output power of 2.9 dBm at 116 GHz, and the output power is higher than 0.5 dBm from 112 to 128 GHz. The power consumption is 160 mW.