Quad-Band Polarization-Insensitive Millimeter-Wave Frequency Selective Surface for Remote Sensing
TL;DR: In this article, a millimeter-wave frequency selective surface (FSS) is presented for demultiplexing four atmospheric remote sensing bands with varying bandwidth (3-20 GHz) and frequency separation (50-195 GHz).
Abstract: A novel millimeter-wave frequency selective surface (FSS) is presented for demultiplexing four atmospheric remote sensing bands with varying bandwidth (3–20 GHz) and frequency separation (50–195 GHz). The unit cell (670 μm × 670 μm) is a circular metal mesh loaded with a monopole integrated concentric ring on a 175-μm-thick quartz substrate designed to reject 50–60 GHz (B1), 87–91 GHz (B 2), and 148–151 GHz (B3), and transmit 175–195 GHz (B4) for transverse electric (TE) and transverse magnetic (TM) polarizations at oblique incidence (25°−35 °). Transmission response of the cascaded FSS measured using a continuous-wave terahertz source showed insertion loss of 15 dB and higher in the reflection windows (B1, B2, and B3) and less than 0.5 dB in the transmission window (B4) for TE and TM polarizations at 30° incident angle.
Citations
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TL;DR: In this paper, a frequency selective surface (FSS) based on hexagon substrate integrated waveguide (HSIW) technology is proposed and designed at the center frequency of 140 GHz.
Abstract: A frequency selective surface (FSS) based on hexagon substrate integrated waveguide (HSIW) technology is proposed in this letter and designed at the center frequency of 140 GHz. The periodic element comprises a HSIW cavity and two circular slots etched on the top and bottom conductor claddings of the cavity. Based on the hexagon cavity, this type of FSS has a better polarization stability and a closer element arrangement compared with square cavity FSS and circular cavity FSS, respectively. Besides, circular slots are better than polygonal slots which have round corners at their corners when fabricated using normal printed circuit board process. Thus, the HSIW FSS can achieve a good and stable performance at terahertz band. The proposed structure is fabricated and the measured result has a good agreement with the simulated one.
20 citations
Additional excerpts
...32λ0 1 No zeros Microfabrication [6] 114 – 2....
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...Two extenders are used to increase the test frequency up to D-band, and two standard D-band horns with the gain of TABLE II COMPARISONS AMONG SEVERAL PLANAR THZ FSSS Center operation frequency f0 (GHz) Percentage bandwidth at –3 dB Insertion loss at f0 (dB) Thickness Number of metallic layers Frequency ratio of transmission zero and f0 Manufacture technology Circular slot in [4] 760 63% 0.14 0.76λ0 1 No zeros Microfabrication Square slot in [4] 315 137% 1.60 0.32λ0 1 No zeros Microfabrication [6] 114 – 2.33 0.46λ0 2 – Microfabrication [10] 222 7% 0.6 0.02λ0 1 0.93 Microfabrication [11] 853 5% 2.5 0.1λ0 3 0.94 Microfabrication This work 141 7% 0.28 0.15λ0 2 0.97 PCB Fig....
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TL;DR: In this article, a penta-band frequency selective surface (FSS) unit cell is proposed, which consists of five metallic structures, two at the top surface and three at the bottom surface of the dielectric, which provide five stopbands in PCS, WiFi, CBRS, lower WLAN and X -band downlink satellite communication frequency ranges.
Abstract: A novel design of a compact penta-band frequency selective surface (FSS) is presented in this letter. The FSS unit cell consists of five metallic structures, two at the top surface and three at the bottom surface of the dielectric, which provide five stopbands in PCS, WiFi, CBRS, lower WLAN, and X -band downlink satellite communication frequency ranges. The mechanisms of stop-band generations are elaborated with current distribution patterns and equivalent circuit modeling. The structure is polarization-insensitive and shows a stable response under oblique incidence up to ±54°. The FSS unit cell is compact with dimensions 0.1 λ × 0.1 λ , where λ signifies the free-space wavelength corresponding to the lowest resonant frequency. A prototype of the proposed FSS is fabricated, and the measured results are in accord with the simulated results.
10 citations
TL;DR: This work presents the measurement of the permittivities of water and methanol in the D-band using a quasi-optical spectroscopy method, which is an improved free-space method more suitable for the millimeter wave range.
Abstract: This work presents the measurement of the permittivities of water and methanol in the D-band. Water is a reference medium for dielectric measurement. The dielectric permittivity of water in the millimeter wave range is a fundamental parameter in many applications, and needs to be investigated systematically. The measurement is conducted using a quasi-optical spectroscopy, which is an improved free-space method more suitable for the millimeter wave range. The theoretical formulae are derived using the signal-flow chart method, which is developed specially for multi-layer operation. This model enables one measure liquid samples. A non-calibration method has been developed to retrieve the permittivity. Water and methanol are measured at several temperatures. The measured results agree with published results in a 4% discrepancy. This work will add new measured data to the permittivities of water and methanol over the whole D-band.
9 citations
TL;DR: In this paper, a polarization rotator based on loaded parallel strip-lines is theoretically and experimentally investigated, where the unit cells are short-stub loaded parallel strips and the arrays on the front and back layers are rotated by 90° to each other.
Abstract: A polarization rotator based on loaded parallel strip-lines is theoretically and experimentally investigated. The unit cells are short-stub loaded parallel strip-lines. The arrays on the front and back layers are rotated by 90° to each other. By loading the stubs, good coupling between the two layers is obtained. Such a structural rotation along with the loading stubs allow the $y$ -polarized wave to be converted to $x$ -polarized wave through field coupling. A broad transmission bandwidth of 30% (86-116 GHz) by using the proposed structure has been reached. In addition, the PTFE substrate is only 0.25 mm thick, which is less than $0.1\lambda $ at 86 GHz. Such a thickness allows the polarization rotator to be easily mounted on antenna radomes. The fabricated prototype demonstrates good agreement between simulation and measurement results.
7 citations
TL;DR: In this article , a single-layer, quartz-supported frequency selective surface (FSS) with a gear-shaped metallic array is proposed for 6G communication, and the simulation indicates that the resonant frequency of 131 GHz with an attenuation of −40 dB can be obtained and the relative bandwidth approximates to 12%.
Abstract: A single-layer, quartz-supported frequency selective surface (FSS) with a gear-shaped metallic array is proposed for 6G communication. Full-wave simulation, along with the method of equivalent circuit, is applied to investigate the transmission characteristics, while the distributions of surface current distribution, as well as electric field and magnetic fields, are studied to further interpret the transmission mechanism. The simulation indicates that the resonant frequency of 131 GHz with an attenuation of −40 dB can be obtained and the relative bandwidth approximates to 12%. The transmission response of the fabricated FSS prototype is measured using the free space measurement setup. The measured results show a good agreement with the simulated ones, which demonstrates the reliability of the design and fabrication. The proposed FSS with the advantages of simple structure, low cost, easy fabrication, and integration can be applied in enhancing the communication performance and anti-interference ability in the future 6G communication system.
6 citations
References
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19 Jul 2015
TL;DR: In this paper, the minimum gap spacing and trace widths are determined by the minimum feature size that can be reliably fabricated using standard PCB lithography techniques, which is the bottleneck of achieving high quality-factor resonators.
Abstract: The selectivity and response type of the frequency response of a frequency selective surface (FSS) are important factors that determine the suitability of an FSS for a given application. A common application of FSSs is to use them to shield sensitive electronic devices form unwanted interference or jamming signals with frequencies close to the main transmission band of the device. In such situations, spatial filters with highly-selective and narrowband transmission windows are required. FSSs with higher-order bandpass or bandstop responses acts similar to coupled-resonator filters. Therefore, their operational bandwidths are inversely related to quality factors of their resonators. Thus, to achieve a narrow-band response, higher quality factors are needed. For the case of traditional FSSs, these resonators are created using resonant elements within a unit cell. Miniaturized-element frequency selective surfaces (MEFSSs), on the other hand, use the combination of non-resonant reactive surfaces with capacitive and inductive surface impedances to create distributed-type resonators. For both approaches, the minimum-attainable feature sizes used in the metallic patterns of the structures are the bottleneck of achieving high quality-factor resonators. In practice, the minimum gap spacing and trace widths are determined by the minimum feature size that can be reliably fabricated using standard PCB lithography techniques. Therefore, achieving very high-quality factors and accordingly narrowband frequency responses for both configurations is rather challenging.
4 citations
"Quad-Band Polarization-Insensitive ..." refers background in this paper
...However, this does not reduce the alignment error [12] between the cascaded FSS layers....
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12 Apr 2015
TL;DR: In this paper, the authors describe the design of a frequency selective surface (FSS) which provides transmission of 228 − 230 GHz radiation and rejection from 164 − 1913 GHz with insertion losses under 025 dB for TE wave polarization at 45° incidence.
Abstract: This paper describes the design of a frequency selective surface (FSS) which provides transmission of 228 – 230 GHz radiation and rejection from 164 – 1913 GHz with insertion losses under 025 dB for TE wave polarization at 45° incidence This state-of-the art filter topology consists of two air spaced freestanding perforated screens, comprising unit cell elements of resonant slots folded for the purpose of miniaturisation to enhance angular stability The reported geometry enhances the angular stability (45° ± 10°) of the FSS beyond what is possible with canonical linear slots and satisfies the stringent electromagnetic performance requirements for signal demultiplexing in the quasi-optical feed train of the Microwave Sounder (MWS) instrument
4 citations
"Quad-Band Polarization-Insensitive ..." refers background in this paper
...The finite size of the FSS (2704 unit cells) and Gaussian profile of the incident plane wave resulted in a small frequency shift (4 GHz) in the measurement at higher frequency as the wavelength is relatively smaller in the B4 band [11]....
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...The proposed unit cell design successfully separated TE and TM polarized EM radiations in four frequency bands spread over 50–195 GHz with varying BW (3–20 GHz) and wide frequency separation ratio....
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...[3] R. Dickie et al., “229 GHz FSS for the MetOp second generation microwave sounder instrument,” in Proc....
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...The insertion loss in B4 is less than 0.5 dB from 180 to 195 GHz....
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...3 shows a transmission null at 136 GHz and 100% BW with less than 18 dB insertion loss in B1 , B2 , and B3 bands, and 20% BW with less than 0.5 dB insertion loss in B4 for TM incidence....
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TL;DR: In this article, a substrate-backed frequency selective surface (FSS) is presented for diplexing the widely separated frequency spectrum centered at 55, 89, and 183 GHz with varying bandwidth for spatial separation in the quasi-optical feed network of the millimeter wave sounder.
Abstract: A substrate-backed frequency selective surface (FSS) is presented for diplexing the widely separated frequency spectrum centered at 55, 89, and 183 GHz with varying bandwidth for spatial separation in the quasi-optical feed network of the millimeter wave sounder. A unit cell composed of a crossed dipole integrated with a circular ring and loaded inside a square ring is optimized for tri-band frequency response with transmission window at 89 GHz and rejection windows at 55 and 183 GHz. The reflection and transmission losses predicted for the optimized unit cell (728 μm × 728 μm) composed of dissimilar resonant shapes is less than 0.5 dB for transverse electric (TE) and transverse magnetic (TM) polarizations and wide angle of incidence (0°–45°). The FSS is fabricated on a 175-μm-thick quartz substrate using microfabrication techniques. The transmission characteristics measured with continuous wave (CW) terahertz transmit receive system are in good agreement with the numerical simulations.
3 citations
"Quad-Band Polarization-Insensitive ..." refers methods in this paper
...Recently, we demonstrated an FSS design to demultiplex three frequency bands for atmosphere temperature profiling (B1 ) and humidity sounding (B2 , B4) [10]....
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...The FSS was fabricated by depositing gold on 175-μm-thick polished quartz substrate using microfabrication techniques described in [10]....
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...waves transmitted by the FSS were collected by the receiver using a plano-convex lens and parabolic mirror arrangement as described in [10]....
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