A 77-GHz Hybrid TDM-MIMO Phased-Array Radar With 186-m Detection Range and 3-cm Range Resolution Zitong Zhang

Abstract

This article presents a fully integrated 77-GHz hybrid time-division-multiplexing multiple-input–multiple-output (TDM-MIMO) phased-array radar in a 55-nm CMOS process. The system integrates eight independent transmitters (8 × 1 TXs) and two four-channel phased-array receivers (2 × 4 RXs), achieving a 4 .76× increase in detection range compared to single-input–single-output (SISO) architecture in long-range radar (LRR) mode and 1.79 ◦ angular resolution with 16 ×4 virtual array in short-range radar (SRR) mode. To realize a large chirp bandwidth while maintaining low voltage-controlled oscillator (VCO) gain ( KVCO), a zig-zag phase-locked loop (PLL)- based frequency-modulated continuous wave (FMCW) generator is proposed, enabling continuous multi-subband chirping. By monitoring the voltage across the capacitance in loop filter ( VCAP) for subband switching, the tuning voltage ( VTUNE) is configured to the optimal switching voltage, eliminating the frequency ripple (FR) during subband switching. Each TX channel integrates switches to support a flexible number and positioning of 1–8 transmitters in TDM mode. To mitigate the leakage e ffect caused by variations in amplitude and phase due to the varying number and position of TX on-channels, a receiver architecture with three low noise amplifiers (LNAs) and a 4-bit phase shifter is designed to achieve low noise figure (NF) and high linearity. Furthermore, an I /Q mixer is designed to achieve orthogonal- ellipse-overlapping-shape NF and p