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This letter presents a 2.5-D frequency selective surface (FSS) based on four-legged loaded loop elements of third-order iteration inspired by fractal geometries. This FSS design strives to harness the efficacy of the space-filling property of fractals and an additional degree of freedom associated with the use of metal vias in planar structures to obtain a miniaturized unit cell by enhancing the electrical length altogether. The proposed FSS provides a band-stop response with resonance at 1.056 GHz and demonstrates identical transmission curves for transverse-electric and transverse-magnetic modes of polarization of the incident wave. The unit cell of the proposed FSS achieves a figure-of-merit (λ0/P) = 29, where λ0 is the free space resonant wavelength and P is the periodicity exhibited by the unit cell, and offers an excellent angular stability up to 75° for oblique incidence. The measured results advocate the real-time shielding effectiveness of the fabricated prototype. [ABSTRACT FROM AUTHOR]

A novel miniaturized frequency selective surface (FSS) with a band-stop response at 1.6 GHz is presented in this letter. The designed FSS comprises convoluted elements connected via plated-through holes, which increases the overall electrical length. The proposed FSS unit cell provides the miniaturization of 0.034 λ0 × 0.034 λ0, where λ0 is the free space wavelength corresponding to the resonant frequency. The drafted FSS is polarization independent and angularly stable for both TE and TM polarizations. A prototype of the FSS is fabricated and its simulated results are validated with measurements. [ABSTRACT FROM AUTHOR]

A reconfigurable frequency-selective surface (RFSS) for electromagnetic shielding applications is presented in this letter. The unit cell of the proposed RFSS contains a pair of shorted square loops separated by a uniform distance. Wideband RFSS with the frequency tuning ratio of 1:2.34 achieved by varying the horizontal spacing is proposed. The RFSS covers the frequencies 3.5, 5, and 5.8 GHz shielding the WiMAX, WLAN, and ISM/WiMAX bands, respectively. The prototype of the proposed RFSS is fabricated and loaded on to the mechanical tuning setup. The tuning setup has a box frame with rotating shafts attached to the bevel gears to control the horizontal spacing. The use of collapsible linkage mechanism ensures uniform spacing during reconfigurable operation. The simulated results are validated with measurements. The proposed FSS offers wideband frequency tuning for electromagnetic shielding applications. [ABSTRACT FROM AUTHOR]

A novel reconfigurable 3-D frequency selective surface (FSS) exhibiting bandstop response is proposed in this paper. The unit cell of the proposed 3-D FSS is constructed from concentric threaded cylinders. The proposed novel 3-D FSS achieves reconfigurability by sliding technique. It offers frequency tuning from 1.86 to 3.10 GHz by sliding the outer cylinder over the inner cylinder. The proposed FSS offers bandstop response in the L- and S-band microwave frequencies. In addition, the proposed 3-D FSS provides polarization- and angular-independent operation. The prototype of the 3-D FSS is fabricated, and the simulation results are validated using measurements. [ABSTRACT FROM PUBLISHER]

A low profile dual-band frequency selective surface (FSS) for shielding the GSM applications is presented in this paper. The proposed FSS contains the unit cell made of modified double square loop elements with paper as its substrate. The overall thickness of the proposed FSS measures only 0.55 mm. The FSS offers band stop response at 930 and 1720 MHz with 18 dB shielding effectiveness for a bandwidth of 100 and 173 MHz, respectively, thus shielding the GSM signals. Additionally, the modified double square loop element-based FSS is symmetrical providing the advantage of polarization independency. It also exhibits angular stability up to 60° for both the horizontal polarized electric field (TE mode) and vertically polarized electric field (TM mode). A prototype of the proposed dual-band low profile FSS is fabricated. The simulation results are compared with the experimental results and are found to be in congruence with each other. [ABSTRACT FROM PUBLISHER]