Abstract-CMOS terahertz imaging pixel with a small on-chip antenna

Shota Hiramatsu, Kosuke Wakita, Seokjin Na, Sayuri Yokoyama, Masayuki Ikebe, Eiichi Sano

https://www.semanticscholar.org/paper/CMOS-terahertz-imaging-pixel-with-a-small-on-chip-Hiramatsu-Wakita/17df7830e3e10988ebd69b16718b1c76c6160eee

We propose a Si–CMOS terahertz image sensor to resolve the lack of low-cost and small-size detectors. The imager chip consists of an imaging pixel array and column ADCs. The imaging pixel consists of an on-chip antenna and an amplifier acting as envelope detector. The pixel used a microstrip patch antenna for receiving THz waves. However, these antennas’ narrow bandwidth and large ground-plane size cause major problems. A low-resistivity Si substrate degrades the gains of planar antennas apart from the microstrip patch antenna. We introduce an on-chip folded-slot antenna to reduce the pixel size and prevent gain degradation due to the Si substrate. The antenna has a broader bandwidth and higher gain than conventional on-chip slot antenna. The folded-slot antenna has about a 0-dBi gain at 0.85 THz and a broader bandwidth than the microstrip antenna in the 0.85 to 1 THz frequency region. The measured results for the THz image sensors with the integrated folded-slot antennas will be reported in near future.