A Tri-Band, Highly Selective, Bandpass FSS Using Cascaded Multilayer Loop Arrays

A new three-dimensional (3-D) frequency selective surface (FSS) based on rectangular waveguide cavities is presented, which realizes a quasi-elliptic bandpass response by multiple transmission zeros/poles. Each unit cell of the proposed FSS is composed of an empty rectangular waveguide cavity and a cuboid circuit board with two back-to-back square loops. With the help of the rectangular waveguide cavities, the electrical and magnetic coupling paths are constructed, resulting in two transmission poles. The constructed out-of-phase signal paths cause two transmission zeros in the upper stopband. To explain the operating principle of the proposed FSS, an equivalent circuit model is given and analyzed using the odd-and even-mode method. A prototype of the proposed FSS is fabricated and measured. The measured results agree well with the simulated results, and show that the FSS can achieve a stable response to variations of incident angle from 0°to 60°for both TE and TM polarizations with wide out-of-band rejection. In addition, the proposed design also realizes a relatively small unit cell.

Section: Equivalent Circuit Analysismentioning

confidence: 99%

3-D dual-polarized bandpass frequency selective surface with quasi-elliptic response based on rectangular waveguide cavity

Zhu

Wang

et al. 2019

“…In recent years, the FSS with simple shape and closely spaced multi-band resonance of miniaturized size and stable response becomes a research hotspot because of the increasing demands on multi-functionality of antennas and filters for both commercial and military applications [7,8]. Dual [9,10,11,12,13,14], triple [15,16,17] and wideband [18,19] FSSs can be used for communication filtering, absorbing or electromagnetic interference (EMI) shielding. However, few can be applied to the passband with wide stopband [20,21].…”

Section: Introductionmentioning

confidence: 99%

A compact FSS with dual passbands and wide stopband

Xia¹,

Liu²,

Tang

et al. 2019

A novel compact multi-band frequency selective surface (FSS) with dual passbands and wide upper stopband is presented. The proposed FSS was originally a double-layer structure. The grid-double square loops (G-DSLs) are located at the bottom to achieve the dual passband characteristics. In order to realize wide upper stopband, a modified square ring and a Jerusalem cross (M-SR-JC) element structure at top and bottom are used. Considering the higher power engineering applications, the final FSS uses a multi-layer structure. The FSS provides two pass-bands centered at 3.8 and 5.8 GHz with relative bandwidths of 18.4% and 13.5%, respectively. It also provides wide stopband characteristics from 10.8 GHz to 14.5 GHz. The simulation and measurement are in good agreement. The novel FSS with dual passbands and wide upper stopband is compact; easy to design and fabricate, and achieves relatively stable multi-band response under different polarization states and different incident angles. The proposed FSS can better meet the engineering requirements.

“…They are used in the design of hybrid radomes, antenna sub-reflectors, absorbers, and polarizers [2,3,4,5]. With the rapid development of multi-functional devices in the satellite communication system, the design of the FSSs with multi-band performances has attracted much attention [6,7,8,9,10,11]. Furthermore, when two channels are closely located in the frequency domain, dual-bandpass FSSs with close band spacing are highly desirable for some applications.…”

Section: Introductionmentioning

confidence: 99%

Dual-bandpass 3-D FSS with close band spacing based on multiple square coaxial waveguides

Tang

Xia

et al. 2019

A three-dimensional (3-D) frequency selective surface (FSS) based on multiple square coaxial waveguides (SCWs) is proposed, which realizes a dual-bandpass response with close band spacing. In the unit cell of the proposed 3-D FSS, two concentric SCW propagation paths and one parallel-plate waveguide (PPW) propagation path are constructed by utilizing three square metallic tubes. Each SCW propagation path intrinsically generates one transmission pole by the square slot resonance, and the PPW propagation path produces another transmission pole by the halfwavelength resonance. In addition, two transmission zeros are introduced due to the counteraction of out-of-phase signals between different paths, improving the frequency selectivity. After properly adjusting the design parameters, two desired passbands are obtained around 4.4 and 4.845 GHz, and the band ratio is only 1.1. Through the electric-field distributions, equivalent circuit model and parameters study, the operating principle of the proposed 3-D FSS is investigated. A prototype of the proposed 3-D FSS is fabricated and measured. The measured results show that the proposed design can achieve a stable response under the incident angles up to 45°for both TE and TM polarizations.