scholarly journals Comparative Study of Square and Circular Loop Frequency Selective Surfaces for Millimeter-Wave Imaging Diagnostics Systems

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3079 ◽  
Author(s):  
Wahab Mohyuddin ◽  
Dong Kim ◽  
Hyun Choi ◽  
Kang Kim
Keyword(s):  
Design Method ◽  
Cell Structure ◽  
Frequency Selective Surface ◽  
Pass Band ◽  
Circular Loop ◽  
Millimeter Wave Imaging ◽  
Wave Imaging ◽  
Design Values ◽  
Fabrication Tolerances ◽  
Frequency Selective

A design method of large-sized square-loop and circular-loop frequency selective surface (FSS) filters for protection of mm-wave imagining receivers is presented. Due to fine cell structure requirements, the performance of the FSS structures at mm-wave frequencies can be significantly affected by fabrication tolerances, especially involved with large-size panel fabrication. Through a comprehensive parametric variation study on the performance of square-loop and circular-loop FSS structures, it is found that the circular-loop FSS structure performs much less sensitively to the fabrication tolerances, thereby producing better and consistent performances with given design values. As a design example, square-loop and circular-loop notch filters resonating at 105 GHz were designed and the performances were evaluated with multiple prototypes. The resonant frequencies of the implemented circular-loop FSS filters deviated by only about 0.5 GHz from the accurate designed value, which can be easily adjusted in the design process. The implemented square-loop and circular loop FSS filters provided low-loss in the pass-band and high rejection of 23 dB at the resonant frequency with good oblique angle performance.

scholarly journals Passive Frequency Selective Surface Array as a Diffuser for Destroying Millimeter Wave Coherence

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Saiful Islam ◽  
Johan Stiens ◽  
Gert Poesen ◽  
Irina Jaeger ◽  
Roger Vounckx
Keyword(s):  
Millimeter Wave ◽  
Random Phase ◽  
Frequency Selective Surface ◽  
Critical Parameters ◽  
Etching Technique ◽  
Millimeter Wave Imaging ◽  
Deterministic Function ◽  
Wave Imaging ◽  
Finite Integral ◽  
Frequency Selective

This paper presents the design, construction, and testing of grounded frequency selective surface (FSS) array as a diffuser for destroying millimeter wave coherence which is used to eliminate speckle in active millimeter wave imaging. To create stochastically independent illumination patterns, we proposed a diffuser based on random-phase distributions obtained by changing the incident frequency. The random-phase diffuser was obtained by mixing up the phase relations between the cells of a deterministic function (e.g., beam splitter). The slot length of FSS is the main design parameter used to optimize the phase shifting properties of the array. The critical parameters of the diffuser array design, such as phase relation with slot lengths, losses, and bandwidth, are discussed. We designed the FSS arrays with finite integral technique (FIT), fabricated by etching technique, and characterized theS-parameters with a free-space MVNA, and measured the radiation patterns with a BWO in motorized setup.

Design and analysis of a tri-band frequency selective surface with a second-order response

2019 ◽  
Vol 12 (3) ◽  
pp. 205-211
Author(s):  
Chunyan Gao ◽  
Hongbin Pu ◽  
Shan Gao ◽  
Chunlan Chen ◽  
Yong Yang
Keyword(s):  
Satellite Communication ◽  
Equivalent Circuit Model ◽  
Design Procedure ◽  
Frequency Selective Surface ◽  
Flat Band ◽  
Pass Band ◽  
Band Frequency ◽  
Transmission Zeros ◽  
Frequency Selective ◽  
Sharp Rejection

AbstractIn this paper, a sandwiched type frequency selective surface (FSS) is designed and analyzed. The design procedure and operating principle is given based on the equivalent circuit model. The proposed FSS includes two identical layers of periodic metallic arrays, which are separated by a foam layer. In each layer of the periodic array, the unit cell is composed of a gridded-triple square loop structure. The FSS provides three pass-bands, in which a flat band response is presented. Three bands are separated by one or two transmission zeros, which leads to a sharp rejection on both sides of each pass-band. The central frequencies of the three pass-bands are 7.0, 10.9 and 14.0 GHz. To verify the simulated results, a prototype of the FSS is fabricated and measured. The simulated results agree well with the measured ones. This work can be used in area of a radar stealth or satellite communication system.

Frequency selective surface filters with polarized band pass/band reject performances

2013 ◽  
Vol 56 (2) ◽  
pp. 483-487 ◽  
Author(s):  
A. G. D'Assunção ◽  
G. Fontgalland ◽  
A. Gomes Neto ◽  
Henri Baudrand
Keyword(s):  
Frequency Selective Surface ◽  
Pass Band ◽  
Band Pass ◽  
Frequency Selective

scholarly journals A Miniaturized Frequency Selective Surface Based on Square Loop Aperture Element

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Wenxing Li ◽  
Chunming Wang ◽  
Yong Zhang ◽  
Yingsong Li
Keyword(s):  
Theoretical Analysis ◽  
Cell Structure ◽  
Frequency Selective Surface ◽  
Unit Cell ◽  
Angle Stability ◽  
Band Pass ◽  
Simulation Results ◽  
Frequency Selective ◽  
Unit Cell Structure ◽  
Periodic Unit Cell

We propose a miniaturized band-pass frequency selective surface (FSS) with periodic unit cell structure. The proposed FSS is realized by symmetrically bending the edges of the square loop aperture element, by which our proposed FSS increases the resonant length, and, hence, reduces its size. In this FSS, each unit cell has a dimension of 0.0538λ × 0.0538λ, whereλrepresents the wavelength of the corresponding resonant frequency. Both the theoretical analysis and simulation results demonstrate that our proposed FSS, having high polarization stability and angle stability, can achieve smaller size in comparison with the previously proposed structures.

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