A sparse array based sub-terahertz imaging system for volume inspection

Imaging systems operating in the sub-terahertz frequency range have proven to be highly attractive devices for non-destructive testing applications. Especially frequency modulated system concepts have shown a great potential for volume inspection in industrial process and quality control, but often lack fast image acquisition times. We report on the development of a line array system for fast sub-terahertz imaging applications. The realized system employs a sparse array consisting of 12 emitters and 12 heterodyne receivers and operates in the W frequency band between 75 GHz and 110 GHz. The applied stepped-frequency continuous-wave radar concept provides 35 GHz modulation bandwidth for fast volume inspections of large test objects in combination with a band-conveyor.