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 ◽  
...  

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.

Author(s):  
Govardhani Immadi ◽  
M. Venkata Narayana ◽  
A. Navya ◽  
C. Anudeep Varma ◽  
A. Abhishek Reddy ◽  
...  

<p>Antennas are long used for communication of data since a century and their usage has been diversified over the past two decades and the antennas also entered the domain of medical fields. A rectangular microstrip patch antenna has been designed on a substrate integrated waveguide with frequency selective surface which is in the shape of a square. The design of this antenna with SIW are done by using CST on a low cost FR4 substrate where є<sub>r</sub> =4.4, h=1.58 mm and tan δ=0.0035. The SIW structure merit is utilized on the traditional FSS is simulated and verified by using CST.</p>


Author(s):  
Hyunwoo Hwang ◽  
Won-Sup Lee ◽  
No-Cheol Park ◽  
Hyunseok Yang ◽  
Young-Pil Park ◽  
...  

Recently, plasmonic nanolithography is studied by many researchers (1, 2 and 3). This presented a low-cost and high-throughput approach to maskless nanolithography technique that uses a metallic sharp-ridge nanoaperture with a high strong nanometer-sized optical spot induced by surface plasmon resonance. However, these nanometer-scale spots generated by metallic nanoapertures are formed in only the near-field region, which makes it very difficult to pattern above the photoresist surface at high-speeds.


2019 ◽  
Vol 11 (3) ◽  
pp. 255-267 ◽  
Author(s):  
Krushna Kanth Varikuntla ◽  
Raghavan Singaravelu

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.


Frequenz ◽  
2017 ◽  
Vol 71 (1-2) ◽  
pp. 57-63 ◽  
Author(s):  
Tao Zhong ◽  
Hou Zhang ◽  
Rui Wu ◽  
Xueliang Min

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.


2021 ◽  
Author(s):  
Foez Ahmed ◽  
Muhammad U. Afzal ◽  
Touseef Hayat ◽  
Karu P. Esselle

Author(s):  
Sergei A. Kuznetsov ◽  
Alexander V. Gelfand ◽  
Victor N. Fedorinin ◽  
Nazar A. Nikolaev ◽  
Pavel A. Lazorskiy ◽  
...  

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 939
Author(s):  
Juan Manuel Munoz-Guijosa ◽  
Rodrigo Zapata Martínez ◽  
Adrián Martínez Cendrero ◽  
Andrés Díaz Lantada

Advances in additive manufacturing technologies and composite materials are starting to be combined into synergic procedures that may impact the biomedical field by helping to achieve personalized and high-performance solutions for low-resource settings. In this article, we illustrate the benefits of 3D-printed rapid molds, upon which composite fibers can be laminated in a direct and resource-efficient way, for the personalized development of articular splints. The rapid mold concept presented in this work allows for a flexible lamination and curing process, even compatible with autoclaves. We demonstrate the procedure by completely developing an autoclave-cured carbon fiber–epoxy composite ankle immobilizing, supporting, or protecting splint. These medical devices may support patients in their recovery of articular injuries and for promoting a more personalized medical care employing high-performance materials, whose mechanical response is analyzed and compared to that of commercial devices. In fact, this personalization is fundamental for enhanced ergonomics, comfort during rehabilitation, and overall aesthetics. The proposed design and manufacturing strategies may support the low-cost and user-centered development of a wide set of biomedical devices and help to delocalize the supply chain for involving local populations in the development of medical technology.


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