CMOS equivalent time sampling of Gaussian monocycle pulse for confocal imaging

CMOS 102.4 GS/s equivalent time sampling (ETS) circuits with a track and hold, phase-locked loop and analog to digital converter was developed for radar-based breast cancer detection. The track and hold circuits of the ETS covered the bandwidth of 2.9-13.9 GHz by use of a 1.27 nH series inductor to compensate parasitic capacitances. The pulse width and the bandwidth of the input Gaussian monocycle pulse (GMP) were 107 ps and 4.45-15.8 GHz, respectively. The received GMP waveforms by 4 × 4 antenna array were converted to 4-bit digital codes. A three dimensional confocal imaging of a 20 × 20 mm² target in a homogeneous breast phantom was demonstrated.