A 90-98 GHz CMOS Transmitter Frontend for Concurrent Phase-Coded FMCW Radar Applications

Abstract

A 90-98 GHz transmitter frontend fabricated in TSMC 65-nm bulk CMOS, capable of concurrent radar-communications applications is presented. A transmitter is proposed that can be used for phase-coded frequency-modulated continuous wave (PC-FMCW) radar as well as for data transmission and interference mitigation. The transmitter architecture is based on an 8-12 GHz IF and ×8 frequency multiplication of a 10-11 GHz local oscillator (LO). Vector IQ summation provides amplitude and phase control, followed by an output power amplifier. Two X-band inputs make the transmitter attractive for a concurrent radar-communication systems as one input is frequency multiplied ×8 while the other is not, allowing upconverting modulated X-band signals. The transmitter achieves full IQ plane control, capable of supporting high-resolution beam steering with P_SAT of 13.7 dBm at 94 GHz. The transmitter consumes 320 mW from a 1.2 V supply (V_DD) and occupies 0.2 mm² core area. The transmitter also presents excellent spectral purity with >30 dB harmonic rejection and a conversion gain of 28 dB.