Terahertz waves hairpin microstrip band-pass filter and its application to overlaid dielectric material detection

A novel terahertz (THz) waves band-pass filter with the center frequency of 880 GHz and low insertion loss using microstrip line hairpin resonators is introduced. The properties of this filter are investigated by finite element method (FEM) simulations. The numerical result shows that the filter has a 3 dB bandwidth from 865 GHz to 892 GHz and has 80 GHz bandwidth better than -10 dB. Resonance frequency shifts of the filter covered by dielectric materials of different permittivity and thickness are calculated, which shows that this type of filter is suitable for detecting the properties of overlaid dielectric materials.