Hou Zhang

A Compact Stable Frequency Selective Surface Using Novel Y-Type Element

In this letter, A compact stable bandpass frequency selective surface (FSS) operating at 3.14 GHz is proposed by using a novel Y-type element. The measured and numerical results are in good agreement, except a little deviation of resonant frequency and a little change of bandwidth, which show that the proposed FSS has good angle and polarization stability. Numerical results show that the dimension of the element is only 0.042λ0 × 0.042λ0 ,w hereλ0 represents the wavelength at the resonant frequency 3.14 GHz. Thus, the FSS is suitable for practical application in limited space.

A single-layer dual-band miniaturized frequency selective surface with compact structure

A novel single-layer dual-band frequency selective surface (FSS) with miniaturized periodic element is proposed and analyzed. Using two symmetric patterns of metallic fractal lines printed on single layer, FSS centered at 4.05 GHz and 5.30 GHz is designed. The simulated results from CST Microwave Solver indicate that the whole dimension of the proposed FSS element is only 7×7mm2, amount to 0.094λ0 × 0.094λ0, where λ0 stands for free space wavelength at first resonant band. Besides, the center frequencies of two bands have scarcely any changes for different polarizations and incidences. The design of the FSS gets a well balance between miniaturization and dual-band. The measured results are in good agreement with the simulated.

A Frequency Selective Surface with Polarization Rotation Based on Substrate Integrated Wavwguide

A frequency selective surface (FSS) with polarization rotation which provides a quasi- elliptic bandpass response is presented in this paper. Based on substrate integrated waveguide cavity (SIWC), 90 degrees polarization rotation is obtained when electromagnetic wave passes through the frequency selective surface at specially appointed polarization in a range of 16.28-16.70 GHz. Moreover, TM120/TM210 dual-mode configuration appears in the cavity within the passband. The design has been proved with high stability to electromagnetic wave of different incident angles. And the measured results in anechoic chamber provide good agreement with those from commercial software simulations.

A Miniaturized Dual-Band FSS with Closely Spaced Resonances Using 2.5-Dimension Structure

Abstract Using 2.5-dimension structure, a novel miniaturized dual-band FSS with closely spaced resonances is proposed in the paper. The special design of the geometry contributes to two closely spaced resonances at 1.69 GHz and 2.16 GHz respectively and the frequency ratio of upper to the lower resonant frequency is 1.27. Besides, the two bands can be controlled individually by varying corresponding parameters. The size of the proposed FSS is only 0.057λ0, where the λ0 represents free space wavelength at lower resonant band. Furthermore, the simulation results show the proposed FSS exhibits stable response with different incident angles and polarizations. To understand the design better, the distribution of surface current is analyzed to explain the operating mechanism of the proposed FSS. Finally, the proposed FSS is fabricated and the measurement results are in accordance with the simulation results.

Wideband Inverted-L Microstrip-via-Fed Circularly Polarized Antenna with Asymmetrical Ground for WLAN/Wimax Applications

Abstract A design with wideband and circularly polarized radiation antenna from an open-slot antenna has been demonstrated in this paper. The proposed antenna, which consists of an open slot and an inverted-L strip feeding, provides a large bandwidth, which completely cover the Wimax (3.3–3.8 GHz) and WLAN (2.4–2.48 GHz) bands. The open slot is formed by an modified ground plane with a slit cut and monofilar spiral stubs employed, which fed by an asymmetrical inverted-L strip feedline using a via. As demonstrated, the CP operation was significantly improved by loading monofilar spiral stubs connected to the asymmetric feedline by means of a via. A parametric study of the key parameters is made and the mechanism for circular polarization is described. After optimization, the impedance bandwidth is approximately 3.78 GHz (2.12 to 5.9 GHz) and the 3 dB axial ratio bandwidth is approximately 2.75 GHz (2.2 to 4.95 GHz), which represent fractional bandwidths of approximately 94.3 % and 76.9 %, respectively.

A OUTSTANDING MINIATURIZED FREQUENCY SELECTIVE SURFACE BASED ON CONVOLUTED INTERWOVEN ELEMENT

Based on convoluted interwoven element, a miniaturized frequency selective surface (FSS) with stable band-stop response is proposed in the paper. By extending the four dipoles into the adjacent elements, the equivalent inductance and capacitance are increased, and therefore the proposed FSS realizes promising miniaturization characteristics. The simulation results indicate that the resonant frequency is 1.19 GHz, and the dimension is only 0.027λ0. Compared to traditional crossed elements, the size is reduced by 94.6%. Besides, the FSS has excellent angle-stability under both TE and TM waves. Finally, the proposed FSS is fabricated and measured, and the experiment results prove the satisfactory consistency with the simulation results.

Novel Dual-Band Miniaturized Frequency Selective Surface based on Fractal Structures

Abstract A novel single-layer dual-band miniaturized frequency selective surface (FSS) based on fractal structures is proposed and analyzed in this paper. A prototype with enough dimensions is fabricated and measured in anechoic chamber, and the measured results provide good agreement with the simulated. The simulations and measurements indicate that the dual-band FSS with bandstop selectivity center at 3.95 GHz and 7.10 GHz, and the whole dimension of the proposed FSS cell is only 7×7 mm2, amount to 0.092λ0×0.092λ0, that λ0 is free space wavelength at first resonant frequency. In addition, the center frequencies have scarcely any changes for different polarizations and incidences. What’s more, dual-band mechanism is analyzed clearly and it provides a new way to design novel miniaturized FSS structures.

Wideband Frequency Selective Surface with a Sharp Band Edge Based on Mushroom-Like Cavity

A wideband frequency selective surface (FSS) with a sharp band edge is proposed. The periodic cell includes a mushroom-like cavity and four L-type slots etched on the top and bottom conductor claddings of the cavity. The measured results show that the proposed FSS operates at X band with a 12.5% bandwidth (7.85-8.90 GHz), in which the insertion loss is less than 3 dB. Comparing with the FSSs based on substrate integrated waveguide cavity, the proposed FSS not only realizes high selectivity, but also realizes a 55.8% reduction in cell size.

A novel miniaturized frequency selevctive surface with polarization selective response

In this paper, a novel miniaturized frequency selective surface (FSS) with polarization selective response is proposed. Compared to previous miniaturized structures, the proposed FSS has better miniaturization performance. Moreover, the simulation results also demonstrate that this structure keeps excellent transmission stability with respect to different incident angles and polarization selective characteristics. Thus, the proposed FSS is suitable for practical application in limited space.