A 100GHz Fully Integrated FMCW Imaging Radar in 110nm CMOS with Fundamental Oscillation Above fmax/2 for Drywall Inspection

This paper proposes a 100GHz fully integrated frequency-modulated continuous-wave (FMCW) radar for drywall inspection. This radar is implemented in 110nm CMOS technology with fmax = 82GHz to lower the cost of fabrication. A modified folded slot as TX antenna with GTX = 11.4dBi and a folded dipole as RX antenna with GRX = 8.8dBi are integrated on the chip. Two techniques in the TX and RX design are utilized to provide fundamental oscillation above fmax/2 and achieve enhanced sensitivity, respectively. On the TX side, a double-negative-resistance method provides 4.3GHz bandwidth from 95.8GHz to 100.1GHz with a maximum EIRP of 2.6dBm and power fluctuation of 1.3dB. On the RX side, the folded dipole antenna maximizes the fundamental voltage swing across sub-harmonic mixer transistors, which improves the noise figure and gain of the mixer. Lastly, this chip is used in a focal plane imaging setup to take images from metallic and PVC pipes behind a 1.25cm thick drywall.