Design and implementation of 2.5D frequency-selective surface based on substrate-integrated waveguide technology

Abstract

In this paper, the patch-type frequency selective surfaces (FSS) based on substrate-integrated waveguide (SIW) technology is proposed to improve the bandwidth (BW) and angular performance. The proposed FSS configuration overcomes the limitations of both conventional 2D and 3D FSS structures. A closely coupled cascaded mechanism is employed to combine two identical FSS elements separated by thin dielectric substrate results in incorporation of SIW technology; hence, named as 2.5D FSS. A derived equivalent circuit model is used to estimate the basic performance of proposed FSS–SIW elements, and the response of analytical expressions has been validated and final design is obtained using full-wave simulations. Two basic FSS elements viz. single square loop and a Jerusalem cross have been investigated to prove the enhancement in their BW and angular stability. The proposed technique evidently improves the BW and angular stability of FSS structures than in its established form. Besides, various important parameters that influence the performance characteristics of reported 2.5D FSSs are also studied. The important observations made on the thickness, as the thickness increases the bandstop FSS, can change to bandpass FSS. Finally, the proposed FSS structure has been fabricated and measured using free space measurement setup, to show the effectiveness of theoretical results. The measured results show good agreement with simulated results at normal and oblique incidence angle.

Angle and polarization-independent miniaturized UWB FSS design

“…In comparison to singlelayer single-sided (SLSS) designs [7][8][9]15] and single-layer double-face (SLDS) designs [16,19,20], the structure designed in this study has an advantage in terms of size while ensuring an excellent fractional BW (FBW) performance. Compared with the 2.5-D FSS structure in [24][25][26], the unit size of the proposed design is 4.2 mm × 4.2 mm, which provides 126% FBW. The resonance frequency under the TE polarization shifts by only 0.003 f 0 at an incident angle of 60°, while the TM polarization shifts by 0.007 f 0 .…”

“…The aforementioned methods are based on the 2-D planar structure. In recent years, a proposed 2.5-dimension (2.5-D) structure represents a new concept for FSS miniaturization research [17,[23][24][25][26]. The upper and lower radiation patches are alternately connected through metallized vias, as demonstrated by Da et al [17], which realizes the single-frequency and dualfrequency miniaturized stop-band FSS design.…”

“…In a study by Yu et al [25], the introduction of metallization resulted in the Jerusalem Cross FSS miniaturization design with the resonance frequency adjusted by the number of vias. In an investigation by Varikuntla et al [26], two identical elements that are separated by a thin dielectric substrate are combined through vias to enhance the stability of the bandwidth (BW) and angle.…”

A design of broadband bandpass frequency selective surface

“…But these structures usually have the disadvantage of narrow bandwidth. Substrate integrated waveguide cavity‐FSSs (SIWC‐FSSs), which depend on the resonant frequency of the SIW cavity were introduced in Guo Qing Luo et al 13 and Varikuntla and Singaravelu 14 . Since the SIWC‐FSSs have a high Q‐factor, it can keep the advantages of high selectivity and cutoff frequency characteristics.…”

A Novel Miniaturized Band‐Stop Frequency Selective Surface With Ultra‐Wideband Characteristics

“…In Mellita et al (2020) covers the wide bandwidth ranging from 1.01 to 9.84 GHz, but it is limited to cover the upper UWB band. Several FSS unit cells are designed with a basic Jerusalem cross structure are discussed in Chen and Tao (2011), Kumar and Vinoy (2021), Varikuntla andSingaravelu (2019), andWei et al (2019).…”