Design of Compact Polarization Insensitive Triple Bandstop Frequency Selective Surface with High Stability under Oblique Incidence

Abstract

This paper proposes a novel design of a triple band frequency selective surface (FSS) that acts as a bandstop filter at 1.92 GHz, 3.5 GHz and 5.64 GHz. The bandstop frequencies resemble to GSM, WLAN and WiMAX application bands respectively. The structure is polarization insensitive since its frequency response remains unaltered for both TE and TM modes of electromagnetic wave propagation. The main attractive feature of the structure is its highly stable response under oblique incident angle up to ±80° at both TE and TM polarizations. Surface current distribution and equivalent circuit modeling are presented to demonstrate the resonance characteristic of the FSS. The structure is compact with an overall unit cell area of 0.09λ  0.09λ, where λ is the wavelength corresponding to the lowest resonant frequency. The proposed structure is compared with other multi-bandstop FSS structures in literature to highlight its superior functionality in terms of stability under oblique incidence and compactness. A prototype comprising of 6  6 array of the proposed unit cell is fabricated and the measured results are in good agreement with the simulated results. KeywordsFrequency selective surface, bandstop filter, polarization insensitive, oblique incidence angle, compact

Miniaturized multiband frequency selective surface with wide frequency ratio

“…Under the TE mode of operation, the oblique incidence exhibits smaller phase variations while the TM mode of operation produces large phase variations. Thus, the bandwidth increases with an increase in oblique incidence for TE mode while it decreases for TM mode of operation 17,18 . The attenuation in TM mode decreases from 24.5 to 17 dB with θ varying from 0° to 60° at 3.2 GHz.…”

“…Thus, the bandwidth increases with an increase in oblique incidence for TE mode while it decreases for TM mode of operation. 17,18 The attenuation in TM mode decreases from 24.5 to 17 dB with θ varying from 0°to 60°at 3.2 GHz. The rest of the band stop frequencies witnesses a maximum of 4 dB reduction in the attenuation level.…”

Design of single‐layer bandstop fractal frequency selective surface based on WLAN applications

“…where Z 0 is the characteristic impedance of free space and ε r is the dielectric constant of the substrate. The resonant frequency caused by each equivalent inductance and equivalent capacitance branch 23 The equivalent circuit model of the proposed FSS structure is simulated in an advanced design system (ADS) to obtain a transmission coefficient curve. 24 Then, the values of each lumped element are extracted by closely fitting the curve with that obtained from HFSS software.…”

“…The characteristic impedance of the dielectric substrate is $${Z}_{\mathrm{sub}}=\frac{{Z}_{0}}{\sqrt{{\varepsilon }_{r}}}$$, where Z 0 is the characteristic impedance of free space and ε r is the dielectric constant of the substrate. The resonant frequency caused by each equivalent inductance and equivalent capacitance branch is $${f}_{r}=\frac{1}{2{\rm{\pi }}\sqrt{{L}_{r}{C}_{r}}}$$, r = 1, 2 23 . The equivalent circuit model of the proposed FSS structure is simulated in an advanced design system (ADS) to obtain a transmission coefficient curve 24 .…”