Design of a hybrid A-sandwich radome using a strongly coupled frequency selective surface element

2020 ◽  
Vol 12 (8) ◽  
pp. 738-748 ◽  
Author(s):  
Krushna Kanth Varikuntla ◽  
Raghavan Singaravelu
Keyword(s):  
Transmission Loss ◽  
Incidence Angle ◽  
Core Layer ◽  
Middle Layer ◽  
Frequency Selective Surface ◽  
Surface Element ◽  
Dielectric Parameters ◽  
Strongly Coupled ◽  
Dielectric Layers ◽  
Frequency Selective

AbstractThe airborne radomes have to cater superior electromagnetic (EM) performance with bandpass characteristics of stealth application. In this regard, a hybrid A-sandwich radome is proposed in this paper. The proposed radome consists of a novel strongly coupled frequency selective surface (FSS) core sandwiched between two dielectric layers (acts as skin) to form an A-sandwich structure. The dielectric layers are cascaded in such a way that the middle layer has less dielectric parameters than the skin dielectric. The core layer comprises a modified FSS array using strongly coupled FSS layers through a series of metallic vias. This strongly-coupled FSS element will have the advantage of eliminating inter-element interference and improves the EM performance characteristics of the structure. The structure exhibits very good band-pass characteristics (>90%) at a normal impinging angle with sharp roll-off characteristics. To show the efficacy of the proposed structure, the transmission loss has been compared with that of conventional A-sandwich radomes at 0°, 50° incidence angle for both TE and TM polarization. Conformal analysis of the unit cell has been carried out, and sector-wise thickness optimization was performed to analyze the structure for the conformal shaped radome application. Finally, a physical prototype has been fabricated and measured its scattering parameters, radiation characteristics in a fully shielded anechoic chamber. The results are encouraging and prove its suitability for radome application.

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

2019 ◽  
Vol 11 (3) ◽  
pp. 255-267 ◽  
Author(s):  
Krushna Kanth Varikuntla ◽  
Raghavan Singaravelu
Keyword(s):  
Incidence Angle ◽  
Equivalent Circuit Model ◽  
Frequency Selective Surface ◽  
Dielectric Substrate ◽  
Angular Stability ◽  
Substrate Integrated Waveguide ◽  
Patch Type ◽  
Angular Performance ◽  
Final Design ◽  
Frequency Selective

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.

A New Hybrid Frequency Selective Surface Design in the 2.4GHz and 5.8GHz ISM Bands

2016 ◽  
Vol 850 ◽  
pp. 9-15
Author(s):  
Bora Döken ◽  
Mesut Kartal
Keyword(s):  
Personal Communication ◽  
Resonance Wavelength ◽  
Frequency Selective Surface ◽  
Surface Element ◽  
Wireless Devices ◽  
Surface Design ◽  
Periodic Cell ◽  
Hybrid Frequency ◽  
Indoor Wireless ◽  
Frequency Selective

With the advancement in telecommunication in indoor environment, the use of wireless technology for information systems has drastically increased. The intensive use of indoor wireless devices in 2.4GHz and 5.8GHz ISM bands causes mutual interference in neighboring networks which degrades the system performance. Secure personal communication within such wireless networks is also another important problem. A band-stop frequency selective surface (operating in the WLAN frequency band) which is attached to the walls of buildings can provide a solution for these interference and security problems. In this work, a new band-stop hybrid frequency selective surface element consisting of two circular looped type geometries is introduced which is capable of attenuating the incoming 2.4GHz and 5.8GHz ISM signals minimum 13dB for all polarizations and incident angles varies from 00 to 450. Besides, a periodic cell size (p=26,5mmm) which is almost one fifth of the first resonance wavelength is obtained.

scholarly journals 3D conformal bandpass millimeter-wave frequency selective surface with improved fields of view

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
H. Fernández Álvarez ◽  
Darren A. Cadman ◽  
Athanasios Goulas ◽  
M. E. de Cos Gómez ◽  
Daniel S. Engstrøm ◽  
...  
Keyword(s):  
High Performance ◽  
Incidence Angle ◽  
Low Cost ◽  
Near Field ◽  
Frequency Selective Surface ◽  
Field Region ◽  
Filter Array ◽  
3D Printed ◽  
Frequency Selective ◽  
Good Agreement

AbstractConventional planar frequency selective surfaces (FSSs) are characterized in the far-field region and they are sensitive to the incidence angle of impinging waves. In this paper, a spherical dome FSS is presented, aiming to provide improved angular stable bandpass filtering performance as compared to its planar counterpart when the FSS is placed in the near-field region of an antenna source. A comparison between the conformal FSS and a finite planar FSS is presented through simulations at the frequency range between 26 to 40 GHz in order to demonstrate the advantages of utilizing the conformal FSS in the near-field. The conformal FSS is 3D printed and copper electroplated, which leads to a low-cost and lightweight bandpass filter array. Placing it in the near-field region of a primary antenna can be used as radomes to realize compact high-performance mm-wave systems. The comparison between simulated and measured conformal FSS results is in good agreement. The challenges that arise when designing, manufacturing, and measuring this type of structure are reported and guidelines to overcome these are presented.

scholarly journals A Tri-band Second-order Frequency Selective Surface Designing and Analysis

2021 ◽  
Vol 275 ◽  
pp. 03084
Author(s):  
Gao Shan ◽  
ChunYan Gao ◽  
HongBin Pu ◽  
ChunLan Chen
Keyword(s):  
Frequency Selective Surface ◽  
Second Order ◽  
Dual Band ◽  
Microwave Filter ◽  
Band Frequency ◽  
Dielectric Layers ◽  
Band Pass ◽  
Frequency Selective ◽  
Band Separation ◽  
Excellent Stability

In this paper, inspired from the technique of patch–aperture–patch, a novel tri-band frequency selective surface with second-order band-pass response in each operation band is presented. The design is implemented by cascading a two-dimensional periodic array of three square loops and an array of wire grids. The proposed structure composed of three metal and two dielectric layers acts as a spatial dual band microwave filter with large band separation. The predicted FSS has the merits of broadband response, excellent stability for different incident angles, and sharp roll-off at X-, Ku- and K-band, respectively. The simulation and measurement are carried out and discussed. The measured results agree well with the simulated ones.

scholarly journals Number of Iteration Analysis for Complex FSS Shape Using GA for Efficient ESG

2018 ◽  
Vol 7 (4) ◽  
pp. 505-513
Author(s):  
Nornikman Hassan ◽  
Zahriladha Zakaria ◽  
Badrul Hisham Ahmad ◽  
Naim Che Pee ◽  
Siti Nadzirah Salleh ◽  
...  
Keyword(s):  
Energy Saving ◽  
Transmission Loss ◽  
Incidence Angle ◽  
Frequency Selective Surface ◽  
Surface Shape ◽  
Metallic Oxide ◽  
Symmetrical Shape ◽  
Improved Performance ◽  
Main Thing ◽  
Iteration Analysis

ESG stand for Energy-Saving Glass is a special shielded glass with a metallic oxide layer to abuse undesirable of infrared and ultraviolet radiation into construction assemblies like our home. Firstly, different number of the iteration is the main thing to study a performance of the frequency selective surface shape using genetic algorithm (GA) for efficient energy saving glass (ESG). Three different values for the number of iterations were taken that is 1500, 2000 1nd 5000. Before that, the response of this complex FSS shape on incident electromagnetic wave with different symmetry shape are investigating. Three of them are no symmetrical shape, ¼ symmetrical shape, and 1/8 symmetrical shape. The 1500 number simulation considered about 89.000 per second, compared with 2000 iteration and 5000 iterations had consumed 105.09 per second and 196.00 per second, respectively. For 1/8 symmetry complex FSS shape, it demonstrations the improved performance of transmission loss at 1.2 GHz with - 40 dB. A 2 dB of transmission loss is achieved at WLAN application of 2.45 GHz with 0°, 30°, and 45° incidence angle shows.

The Use of Fabric Composite Frequency Selective Surface in Sandwich Structures for Low-Observable Radomes

2013 ◽  
Vol 281 ◽  
pp. 448-452 ◽  
Author(s):  
Chang Liang Li ◽  
Da Zhi Jiang ◽  
Jing Cheng Zeng
Keyword(s):  
Sandwich Structure ◽  
Transmission Loss ◽  
Sandwich Structures ◽  
Single Layer ◽  
Frequency Selective Surface ◽  
Transmission Characteristics ◽  
3 Dimensional ◽  
Layer Composite ◽  
Fabric Composite ◽  
Frequency Selective

In this work, the hybrid fabrics of carbon and quartz fibers as filters were adopted in PMI core sandwich structures for low-observable radomes. The advantages of fabric composite frequency selective surfaces (FCFSSs) are easily fabricated by braiding and shaped into curved surfaces. This paper mainly studied the electromagnetic (EM) transmission characteristics of the low-observable radome wall with composite FSS by 3-dimensional electromagnetic analysis software. First of all, the accuracy of the simulation model composed of up and down composite face sheets, a layer of composite FSS and PMI core was validated by comparing with experimental results. Then, the studies on electromagnetic transmission characteristics of the sandwich structure with composite FSS and the sensitivity analysis about the thickness and permittivity of face sheets and PMI core were carried out. The results show that the sandwich structure with single layer composite FSS can realize the function of frequency selection, limit the reflection at the resonance frequency and decrease the sensitivity of EM transmission loss about the thickness of sandwich structures.

scholarly journals Scalable Frequency Selective Surface with Stable Angles of Incidence on a Thin Flexible Substrate

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
In-Gon Lee ◽  
Ic-Pyo Hong
Keyword(s):  
Incidence Angle ◽  
Flexible Substrate ◽  
Wide Band ◽  
Frequency Selective Surface ◽  
Dielectric Substrate ◽  
Minimum Size ◽  
Angle Of Incidence ◽  
Response Characteristics ◽  
Frequency Selective ◽  
5 Ghz

A band-stop scalable frequency selective surface (FSS) structure that provides stability for an angle of incidence and polarization is designed using the repetitive arrangement of a unit structure miniaturized on a thin dielectric substrate. The designed miniaturized FSS has a hexagonal unit cell of a minimum size of 0.081 λat 2.5 GHz in which a triangular loop is repeated. In addition to the frequency stability, the proposed structure reduces the design complexity that is the biggest shortcoming of the miniaturization techniques studied previously. A scalable FSS structure possessing stable frequency response characteristics over a wide band ranging from 2 to 8 GHz, which is achieved by the control of a single design variable, can be designed. For verification of the proposed structure, FSS structures that operate in the bands of 2.5 GHz, 5 GHz, and 8.2 GHz have been designed and fabricated on a very thin substrate. It has been confirmed that the results of the measurement and simulation correspond well with each other. The designed structures also demonstrate high stability for both the polarized wave and the incidence angle of the incident wave.

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