Distributed Power Combiner and On-Chip Antennas for Sub-THz Multi-Band UWB Receivers

This paper presents the analysis, the design, and the characterization of the first stage of a sub-THz receiver. The system consists of an on-chip two-time stacked Vivaldi-shaped open slot antenna and a fractal bowtie antenna integrated with a distributed power combiner. The integrated circuit is designed for operation in two wide frequency bands centered at 110GHz and 180 GHz. The employed fabrication process is a 130nm SiGe BiCMOS technology featuring HBTs with f
_max
of 450 GHz. A design procedure based on the co-design of antenna and amplifier predicted variations of the receiver gain within 3 dB in the frequency range of interest, confirmed with the experimental result. 5 dB of maximum gain has been demonstrated, with variation below 6 dB in the frequency range from 95 GHz to 125 GHz, and from 160 GHz to 200 GHz. Compared to the state of art, the presented design owns one of the largest reported absolute and relative frequency bandwidth of operation, and it is the first demonstration of multi- and wide-band operation in the frequency range 90 GHz - 220 GHz.