A 77-GHz SiGe Integrated Six-Port Receiver Front-End for Angle-of-Arrival Detection

In this paper an integrated six-port receiver front-end for angle-of-arrival detection of 77-GHz signals is presented. Applications of the circuit are direction finding, automotive radar calibration, or high precision industrial radar. The measurement principle is based on passive superposition of two incident signals and power detection. The circuit features two input amplifiers, a broadband passive six-port network, and four power detectors. The integrated circuit has a power consumption of 95 mW with 5 V supply voltage. It is fabricated in a 200-GHz f_T SiGe bipolar technology and occupies only 1028 × 1128 μm². The circuit operates in a 3-dB bandwidth from 75 GHz to 84 GHz and has a responsivity of 152 kV/W at 80 GHz. A simple calibration method is proposed and all calibration parameters are calculated for different frequency values.