Article ID: 14.20170796
The transmission characteristics of a frequency selective surface (FSS) consisting of small resonant circular apertures with a ridge are related to the transmission cross section of a single ridged aperture, and the performance is verified experimentally. The FSS structure with a ridged circular aperture has a lower resonant frequency, enlarged fractional bandwidth, and a larger wavelength-to-periodicity ratio compared to an FSS with a conventional circular aperture. Experiment results show that the resonant frequency of the proposed FSS structure can be lowered from 13.98 GHz to 7.30 GHz (47.8%) by adding the ridge.