A Convoluted Structure for Miniaturized Dual-Bandstop Frequency Selective Surface

A miniaturized dual-bandstop frequency selective surface (FSS) using convoluted structures is proposed in this letter. The working central frequencies of the proposed FSS are 2.66 and 5 GHz with -3 dB bandwidths of 1.5 and 1.2 GHz, respectively. The side length of the unit cell is 6.88 mm, which is about 5.9% of the wavelength at the first working frequency. The equivalent circuit and current distributions are introduced to explain the FSS frequency performance. The effects of the geometrical parameters on the frequency response of the FSS are studied. The simulated results show that the ratio of the frequencies of the two working transmission zeros can be tuned over a wide range. A prototype of the proposed FSS is fabricated and measured. The simulation and measured results show that the working frequencies, the bandwidths of the passband, and two stopbands of the proposed FSS perform excellent stabilities under different polarizations and incidence angles. This FSS is a good candidate to isolate the wireless networks.