A High-Linearity 76–85-GHz 16-Element 8-Transmit/8-Receive Phased-Array Chip With High Isolation and Flip-Chip Packaging

An SiGe transmit-receive phased-array chip has been developed for automotive radar applications at 76-84 GHz. The chip is based on an all-RF beamforming approach and contains 8-transmit channels, 8-receive channels, and a complete built-in-self-test system. Two high-linearity quadrature mixers with an input P1 dB of +2.5 dBm are used and allow simultaneous sum and difference patterns in the receive mode. The chip operates in either a narrowband frequency-modulated continuous-wave (FMCW) mode or a wideband mode with > 2-GHz bandwidth. A high-linearity design results in an input P1 dB of -10 dBm (per channel), a system noise figure of 16-18 dB, and a transmit power is 4-5 dBm (per channel). The chip uses a controlled collapse chip connection (C4) bumping process and is flip-chipped on a low-cost printed-circuit board, and results in > 50-dB isolation between the transmit and receive chains. To our knowledge, this work represents the state-of-the-art in terms of complexity at millimeter-wave frequencies and with simultaneous transmit and receive operation for high-performance FMCW radars.