Design of a single layer broadband tunable frequency selective surface

Tunable frequency selective surfaces (FSSes) usually have better flexibility and are employed by many applications. However, the frequency tunable range is usually not very broad especially for the band-stop ones. At the same time, a tunable FSS usually requires a bias network, which makes the design even more difficult. In this paper, a broadband tunable band-stop AFSS is presented. The tunable ability is achieved by the varactors mounted on the surface. By tuning the reverse voltage, the stop-band is controlled continuously. The measured resonant frequency tunable range is from 935 MHz to 2.405 GHz. At the same time, no additional bias grid is required and only one layer of the PCB is occupied.