A 400-GHz 28-nm TX and RX With Chip-to-Waveguide Transitions Used in Fully Integrated Lensless Imaging System

This paper presents a 400-GHz CMOS TX and RX chip with two different chip-to-waveguide transitions. The first design is based on a coupled microstrip to waveguide coupler and is integrated together with a 400-GHz oscillator in 28-nm bulk CMOS. When this transmitter is combined with a micromachined horn antenna, it is capable of providing an equivalent isotropic radiated power of 1.26 dBm. In the second design, a folded dipole based coupler is utilized to make the transition between a waveguide and a 400-GHz mixer first receiver. This receiver fully integrates an on-chip local oscillator, mixer, and baseband circuits and achieves an effective conversion gain of 39 dB and a noise figure of 45 dB. Both chips are combined into a lensless active imaging setup with a spatial resolution of 2 mm.