3D Frequency Selective Surface Research Articles

Advance 3D FSS with several transmission zeros for S, C and X frequency

The advanced 3D Frequency Selective Surface (FSS) is intended from a 2D regular array of two guarded micro strip lines that comprise a single element cell. The designed 3D FSS exhibits elliptic band-pass responses for two frequency ranges (3.64–4.7) GHz and (7.65–9.6) GHz, which lie in the S, C, and X microwave frequency bands. The transmission zeros have been provided at 3.4 GHz, 5 GHz, 6.6 GHz, and 10 GHz frequencies to improvise the selectivity of the FSS filter. The FSS response is self-sufficient of the level signal until the angle of attack varies by 50°. Every element cell of the guarded micro strip lines consists of an air slot with a T-shaped metal sheet. When a TE contrasted level signal coincidences perpendicularly to the dual guarded micro strip lines, The air quasi-TEM mode along with the substrate quasi-TEM mode resulted. Transmission poles are obtained in phase resonating modes combinations, whereas transmission zeros are obtained in out of phase resonating modes combinations. The versatile ANSYS HFSS simulation software is used to plan and reproduce the proposed 3D FSS composition. The obtained outcomes show enhanced presentation of the above two-dimensional (2D) FSS composition with the designed 3D FSS finds numerous actual approaches like spatial filters, radomes, and antenna sub-reflectors.

3D Flexible Frequency Selective Surface with Stable Electromagnetic Transmission Properties (Adv. Mater. Technol. 7/2022)

3D Frequency Selective Surfaces In article number 2101316, Yuhang Li, Taisong Pan, and co-workers present a 3D flexible frequency selective surface fabricated by releasing pre-strains in the flexible substrate and thus buckling the 2D Jerusalem metal precursors locally bonded on it, capable of being conformally adhered to complex surfaces, which can maintain stable frequency-selective properties as well as transmission performance when subjected to biaxial stretching strains.

3D Microstructured Frequency Selective Surface Based on Carbonized Polyimide Films for Terahertz Applications

AbstractIn recent years, frequency selective surface (FSS)‐based two‐dimensional (2D) and three‐dimensional (3D) carbon materials such as carbon nanofibers, carbon nanotubes, and carbon‐filled filaments are essential tools to design millimeter‐wave radomes, absorbers, electromagnetic interference (EMI) shielding, and antenna reflectors in gigahertz (GHz) regimes. Terahertz (THz) technologies are gaining attentions from medical imaging to security surveillance. In this work, a 3D microstructured FSS using carbon‐based polyimide as a precursor to enhance the resonant frequency at the THz range. Furthermore, gold nanoparticles (AuNPs) are embedded on 3D microsturctured carbonized polyimide (3D‐CPI) film to improve their FSS property through plasmonic effects. From the time domain spectroscopy measurements, 3D‐CPI FSS film shows band‐stop filter properties in the frequency range of 0.5–1.5 THz and with a maximum return loss (RL) of 40.5 dB (at the resonant frequency of 1 THz). The 3D‐CPI/AuNPs film demonstrates the highest RL of 43.7 dB at the higher excitation resonance frequency ≈1.06 THz due to the interaction of plasmonic electrons with scattered delocalized electrons in carbon, which induces the mechanisms for EMI shielding. The results will open insight into 3D plasmonic carbon microstructures as an EMI shielding material at THz frequency.

Compact Dual-Passband Three-Dimensional FSS with Good Angular Stability and Both-Side Fast Roll-Off Characteristics

A compact dual-passband three-dimensional (3D) frequency selective surface (FSS) is proposed based on multiple square coaxial waveguides (SCWs), which exhibits good angular stability and both-side fast roll-off characteristics. The unit cell of the proposed 3D FSS is composed of one parallel plate waveguide (PPW) propagation path and two SCW propagation paths. By etching a centered annular slot, each SCW path forms two identical short SCWs. Each short SCW inherently generates one square slot resonance. In each SCW path, on the account of electromagnetic coupling between two square slot resonators provided by two short SCWs, the square slot resonant mode will split into even-/odd-resonant modes. Accordingly, each SCW path can provide a flat second-order passband with two transmission poles. Due to the reflection and out of phase of electromagnetic waves, four transmission zeros located at both sides of the passbands are introduced for high frequency selectivity, realizing both-side fast roll-off performances. In order to explain the operating principle, the electric-field distributions at transmission-zero/pole frequencies are investigated. Finally, an FSS prototype is fabricated and measured, and the results exhibit good angular stability for both TE and TM polarizations under incident angles from 0° to 60°. In addition, the proposed 3D FSS has a compact unit cell.

Enhancing 5G antenna performance by using 3D FSS structures

In this work, an enhanced 3D frequency selective surface (FSS) patch antenna is proposed for 5G applications. A 23 to 26 GHz patch antenna was first designed before improving its performance by adding a 3 × 5 unit cell two-layer 2D transmission FSS structure. Then, reflective walls were placed on the side edges of the obtained structure in order to focus the incident field towards the main lobe; the aim being to build a 3D FSS structure without requiring the 3D printing technique. The total size of the obtained antenna is of 40 × 40 × 14 mm3. A comparative study was carried out between the performances of the patch antenna, the 2D FSS antenna and the 3D FSS antenna. A good agreement was observed between simulated results and measurements. An improvement of almost 3 and 2 dBi was obtained compared to the 2D FSS case, respectively, in simulated and measured results, while the side lobes in radiation patterns were decreased by more than 4 dBi, which confirms the adequate proposed design in switching to 3D structures.

Compact three‐dimensional bandpass FSS with high selectivity based on split square coaxial waveguide

In this Letter, a compact three-dimensional (3D) frequency selective surface (FSS), exhibiting a bandpass filtering response with high selectivity, is proposed based on the split square coaxial waveguide (SSCW). The unit cell of the presented 3D FSS consists of one parallel-plate waveguide propagation path and one SSCW propagation path. In the SSCW path, two identical short SCWs are produced by employing a centred annular slot. Each short SCW intrinsically provides a square slot resonance. Owing to the electromagnetic coupling between these two square slot resonances, original single square slot resonant mode will split into even-/odd-resonant modes, resulting in a flat passband with two transmission poles. Moreover, two transmission zeros located at both sides of the passband are introduced for high selectivity, because the electromagnetic waves passing through these two different paths are combined out of phase. By investigating the electric-field distributions at the frequencies of the transmission zeros/poles, the operating principle of the proposed 3D FSS is described. A prototype of the proposed 3D FSS is fabricated and measured. The measured results show that the proposed design can achieve a stable response under the incident angles up to 60° for both TE and TM polarisations.

Dual‐band three‐dimensional FSS with high selectivity and small band ratio

In this Letter, a three-dimensional (3D) frequency selective surface (FSS) is proposed, exhibiting a dual-bandpass response with high selectivity and small band ratio. The unit cell of the presented 3D FSS consists of a pair of gridded double square loops (GDSLs) and a waveguide structure. Multiple transmission zeros and transmission poles are obtained from the electromagnetic coupling between the GDSLs. The electromagnetic coupling is enhanced by the waveguide structure, resulting in a dual-passband behaviour with high selectivity. Double square loops are designed to locate close to obtain a small band ratio. The measured results of the implemented FSS agree well with the simulated ones, which show that the proposed design can achieve the desired response to variations of incident angle from 0° to 60° for both TE and TM polarisations.

3D FSS polarizer for millimeter‐wave antenna applications

In this article, a novel wideband polarizer is presented, to convert the linear polarization of a directive antenna into circular polarization. This innovative polarizer is based on a 3D frequency selective surface (FSS) and consists of an array of 4×4 metal axial-mode helices. The proposed broadband polarizer operates in the 28 to 31 GHz frequency band. To demonstrate the principle, the 3D FSS is applied to a linearly polarized Yagi-Uda antenna operating in the same millimeter-wave frequency band. The measured and simulated results, by integrating the proposed 3D polarizer in front of the antenna, show that an axial ratio smaller than 3 dB is obtained over a wide bandwidth with gain enhancement.

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

AbstractIn 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.

Notice of Retraction: Experimental Validation of a 3D FSS Designed by Periodic Conductive Fibers Part-1: Band-Pass Filter Characteristic

This study covers the design, manufacturing, and experimental electrical tests for a novel three-dimensional (3-D) band-pass frequency selective surfaces (FSS) containing continuous and discontinuous conductive fibers. The proposed FSS is designed based on 3-D numerical simulations to operate in the frequency range 8–12 GHz with resonant frequency at around 9.5 GHz. An equivalent circuit model of the proposed FSS is constructed to predict and understand the electrical behavior of the structure. Moreover, the experimental result of a fabricated prototype is obtained to demonstrate the validity of both the simulation results and the equivalent circuit model prediction. Furthermore, a quasi-isotropic multilayer FSS having fibers with different orientations is considered to provide a band-pass filter performance under various incident angles for both transverse electric (TE) and transverse magnetic (TM) polarizations.

3D‐tapered resonators for FSSs with incident angle independence

A three-dimensional (3D) frequency selective surface (FSS) with a response that is independent of incident angle is presented in this study. The proposed FSS is a periodic array of 3D hollow-tapered resonators. The proposed 3D FSS has reduced sensitivity to the angle of incidence of the electromagnetic wave compared with other 2D and 3D FSSs as a result of tapered structure. The transverse electric (TE) and transverse magnetic (TM) incident angle independences are obtained by tapering the width of a cylinder with a square cross-section from the upper opening to the lower opening. Impressive frequency stability and transmission characteristics have been achieved up to 80° for both TE and TM incidence angles. The principles of operation along with guidelines for the design of the proposed FSS structures are presented in this study. A prototype of the proposed 3D-tapered FSS is also fabricated and tested using a free-space measurement system to verify performance.

РЕЗОНАТОР ФАБРИ–ПЕРО, ОБРАЗОВАННЫЙ ДВУМЯ ЭКРАНАМИ С ПРЯМОУГОЛЬНЫМИ ОТВЕРСТИЯМИ

PACS number: 41.20.–q Purpose: studies of electrodynamics properties of Fabry–Perot resonator formed by two parallel perfectly conducting screens of finite thickness with rectangular holes while its exciting by a plane wave. Design: operator method of diffraction problems solving based on the method of partial areas and the method of generalized scattering matrixes. Findings: The numerical modeling showed that module of the coefficient of plane wave reflection from the resonator is equal to zero at a fixed wavelength being prohibitive for segments of rectangular waveguides made in both screens. Here, a strong localization of electromagnetic field in the resonator volume is observed. Studying the frequencyselective properties of each screen individually it has been determined that there are no resonances of electromagnetic wave total transmission below the cut-off frequency of rectangular waveguides. It is found that with replacing one of the Fabry–Perot resonator mirrors by a solid metal plane, the amplitude of a plane wave in the resonator can increase by almost an order of magnitude as against the exciting field amplitude. Conclusions: Unique electrodynamic properties of the considered structure can find application in devices for amplifying or generating electromagnetic waves in millimeter and submillimeter bands, as well as in measuring electrical properties of composite materials with large losses. Key words: two-dimensional periodic screen, rectangular waveguide, Fabry–Perot resonator, reflection coefficient, ultraboundary waveguide Manuscript submitted 11.11.2015 Radio phys. radio astron. 2016, 21(1): 58-64 REFERENCES 1. EULER, M. and FUSCO, V., 2010. Frequency Selective Surface Using Nested Split Ring Slot Elements as a Lens with Mechanically Reconfigurable Beam Steering Capability. IEEE Trans. Antennas Propag . vol. 58, no. 10, pp. 3417–3421. DOI: https://doi.org/10.1109/TAP.2010.2055814 2. AZEMI, S. N., GHORBANI, K. and ROWE, W. S. T., 2012. 3D Frequency Selective Surfaces. Prog. Electromagn. Res . C. vol. 29, pp. 191–203. DOI: 10.2528/PIREC12033006 3. BANKOV, S. E., DUPLENKOVA, M. D. and FROLOVA, E. V., 2013. Eigenmodes of resonator on the basis of an electromagnetic crystal. Zhurnal Radioelektroniki . no. 7, pp. 1–27 (in Russian). 4. ZIRAN WU, WEI-REN NG, MICHAEL E. GEHM and HAO XIN., 2011. Terahertz electromagnetic crystal waveguide fabricated by polymer jetting rapid prototyping. Opt. Express . vol. 19, no. 5, pp. 3962–3972. DOI: https://doi.org/10.1364/OE.19.003962 5. ANTONENKO, J. V. and GRIBOVSKY, A. V., 2012. Polarization and Frequency-Selective Properties of a Double Screen of Finite Thickness with Coaxial-Sector Aperture. Radio Phys. Radio Astron . vol. 17, no. 3, pp. 276–281 (in Russian). 6. GRIBOVSKY, A. V., LYTVYNENKO, L. M. and PROSVIRNIN, S. L., 2000. Diffraction of Electromagnetic Waves on a Multi-Layer Structure of Metal Screens with Rectangular Holes. Radio Phys. Radio Astron . vol. 5, no. 2, pp. 166–170 (in Russian). 7. PEROV, A. O., KIRILENKO, A. A., DERKACH, V. N. and SALOGUB, A. N., 2015. System of two screens with the circular beyond the limits openings as the quasi-optical polarizer. Radiofizika i Elektronika . vol. 6(20), no. 3, pp. 3–10 (in Russian). 8. LITVINENKO, L. N. and PROSVIRNIN, S. L., 1984. Spectral operators of dispersion in the tasks of diffraction of waves on flat screens . Kyiv: Naukova dumka (in Russian). 9. GRIBOVSKY, A. V., PROSVIRNIN, S. L. and REZNIK I. I., 1997. Reflecting Phased Array Antenna Consisting of Rectangular Waveguides of Finite Depth. Radio Phys. Radio Astron . vol. 2, no. 1, pp. 52–60 (in Russian).

3D frequency selective surface for stable angle of incidence

A three-dimensional frequency selective surface (3D-FSS) that provides stability for an angle of incidence and miniaturised unit cell size is presented. The proposed 3D-FSS is easy to fabricate and is implemented using via holes in a multilayer printed circuit board structure. Frequency transmission characteristics for different angles of both TE and TM polarisations are presented through simulations. The proposed structure was fabricated so as to verify the simulation results. The comparisons between the simulation and the measured results show good agreement. The results also show that the proposed 3D-FSS can provide better frequency stability for different incidence angles and polarisations as well as miniaturised unit cell size.

3D FREQUENCY SELECTIVE SURFACES

A novel 3D Frequency Selective Surface (FSS) architecture based on a circular ring unit element is presented. The circular ring was made 3D by creating a cylindrical element of a certain length, adding an extra degree of freedom into the structure. The length of the cylinder is shown through electromagnetic simulation to have a signiflcant efiect on the frequency characteristics of the FSS. Increasing the length of the cylinder can change the FSS from a band-stop to a band-pass fllter response. The center frequency of both band pass and band stop responses can also be tuned with adjustment to the length. Dielectric materials are introduced in the center of the cylindrical unit cell elements to simultaneously obtain a stop and pass band with a sharp transition. For high dielectric fllling materials, the 3D periodic structure exhibits negative refractive index metamaterial properties. A parametric analysis was conducted on these new cylindrical unit elements, and a prototype 3D FSS structure has been constructed and experimentally validated.