Publication
This article presents the design of an ultralow power short-range 57-66 GHz frequency-modulated continuous-wave (FMCW) radar. The transmitter (TX) path includes a BPSK modulator in order to implement a low-IF architecture and it is optimized for short-range operation with 0 dBm output power. The receiver (RX) path is designed accordingly as a low-IF I/Q mixer-first for low power. The low-IF modulation minimizes the impact of LO-RX leakage, dc offsets, and flicker noise. It also allows orthogonal modulations for RX separation in multiple-input multiple-output (MIMO) operation. A band-tuning technique is used in the TX and RX for covering the wide band and it is tuned as the frequency is swept. The local oscillator (LO) distribution is designed in a modular approach to be able to extend the number of TX and RX paths for MIMO. The frequency synthesis is based on a quadrature digitally-controlled oscillator (QDCO) exploiting the coupling mechanism to achieve a maximum seamless and ultrawide frequency tuning range up to 11 GHz. A wide-band and low-power divider chain is designed using dynamic topologies. An all-digital phase-locked loop (ADPLL) is closed off-chip by means of an FPGA platform providing flexibility for the design and test of the digital loop filter without the need for extensive calibration. The 2-TX & 2-RX radar is integrated into GF 22-nm FDSOI CMOS technology. The average continuous power consumption is only 44.2 and 68.5 mW for 1-TX & 1-RX and 2-TX & 2-RX configuration, respectively.