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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26 Apr 2000
TL;DR: In this article, the authors present a comparison of band-pass and Dichroic filter designs for one and two-dimensional periodic structures, and present an overview of the current state-of-the-art.
Abstract: General Overview. Element Types: A Comparison. Evaluating Periodic Structures: An Overview. Spectral Expansion of One- and Two-Dimensional Periodic Structures. Dipole Arrays in a Stratified Medium. Slot Arrays in a Stratified Medium. Band-Pass Filter Designs: The Hybrid Radome. Band-Stop and Dichroic Filter Designs. Jaumann and Circuit Analog Absorbers. Power Handling of Periodic Surfaces. Concluding Remarks and Future Trends. Appendices. References. Index.
3,896 citations
"Quad-Band Polarization-Insensitive ..." refers background in this paper
...To achieve 100% bandwidth (BW) coverage in the four bands, two FSS layers were cascaded with a finite air gap h [1]....
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...FREQUENCY selective surface (FSS) is a synthesized metallic structure printed on a dielectric substrate for filtering electromagnetic (EM) wave [1]....
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TL;DR: This new class of quasi-optical filter exhibits an insertion loss <;0.3 dB at 700 GHz and can be designed to operate independently of the polarization of the incident signals at oblique incidence.
Abstract: The purpose of this paper is to review recent developments in the design and fabrication of Frequency Selective Surfaces (FSS) which operate above 300 GHz. These structures act as free space electromagnetic filters and as such provide passive remote sensing instruments with multispectral capability by separating the scene radiation into separate frequency channels. Significant advances in computational electromagnetics, precision micromachining technology and metrology have been employed to create state of the art FSS which enable high sensitivity receivers to detect weak molecular emissions at THz wavelengths. This new class of quasi-optical filter exhibits an insertion loss <;0.3 dB at 700 GHz and can be designed to operate independently of the polarization of the incident signals at oblique incidence. The paper concludes with a brief overview of two major technical advances which will greatly extend the potential applications of THz FSS.
109 citations
"Quad-Band Polarization-Insensitive ..." refers methods in this paper
...Transmission loss due to substrate [6] in millimeter and submillimeter wavelengths was eliminated using freestanding FSS [7]–[9]....
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TL;DR: The requirements for, and the design of, quasi-optical antennas for radiometric remote-sensing are discussed with particular reference to the Advanced Microwave Sounding Unit AMSU-B, which was designed and built by Matra Marconi Space UK for the UK Meteorological Office and is due to be placed in orbit on a satellite.
Abstract: Millimetre- and submillimetre-wave radiometers are employed for remote-sensing of the Earth's atmosphere. They must operate in several widely-spaced frequency bands which together might exceed the fundamental bandwidth of a waveguide. A wholly independent radiometer for each band would be inefficient and considerable savings in space and weight can be achieved if all bands are received via a single aperture antenna and then separated by an optical demultiplexer, the arrangement comprising a `quasi-optical' antenna. This paper discusses the requirements for, and the design of, quasi-optical antennas for radiometric remote-sensing and illustrates this with particular reference to the Advanced Microwave Sounding Unit AMSU-B, which was designed and built by Matra Marconi Space UK for the UK Meteorological Office and is due to be placed in orbit on a satellite.
73 citations
"Quad-Band Polarization-Insensitive ..." refers methods in this paper
...FSSs are used in the quasi-optical receiver of the remote sensing radiometers to demultiplex the incoming EM radiation and route the spectral emission to the respective receive modules for weather monitoring [2]....
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TL;DR: In this paper, a multilayer freestanding slot array is designed to give an insertion loss which is significantly lower than the value obtainable from a conventional dielectric backed printed frequency selective surface (FSS).
Abstract: In this paper, we show that a multilayer freestanding slot array can be designed to give an insertion loss which is significantly lower than the value obtainable from a conventional dielectric backed printed frequency selective surface (FSS). This increase in filter efficiency is highlighted by comparing the performance of two structures designed to provide frequency selective beamsplitting in the quasioptical feed train of a submillimeter wave space borne radiometer. A two layer substrateless FSS providing more than 20 dB of isolation between the bands 316.5-325.5 GHz and 349.5-358.5 GHz, gives an insertion loss of 0.6 dB when the filter is orientated at 45/spl deg/ incidence in the TM plane, whereas the loss exhibited by a conventional printed FSS is in excess of 2 dB. A similar frequency response can be obtained in the TE plane, but here a triple screen structure is required and the conductor loss is shown to be comparable to the absorption loss of a dielectric backed FSS. Experimental devices have been fabricated using a precision micromachining technique. Transmission measurements performed in the range 250-360 GHz are in good agreement with the simulated spectral performance of the individual periodic screens and the two multilayer freestanding FSS structures.
62 citations
"Quad-Band Polarization-Insensitive ..." refers methods in this paper
...Transmission loss due to substrate [6] in millimeter and submillimeter wavelengths was eliminated using freestanding FSS [7]–[9]....
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TL;DR: A complete theoretical analysis based on the waveguide theory and Fermat's principle is provided and numerical simulation results of two-dimensional and three-dimensional lenses, made of PEC and aluminum, respectively, and working in the terahertz regime, which show good agreement with the analytical work.
Abstract: An epsilon-near-zero graded-index converging lens with planar faces is proposed and analyzed. Each perfectly-electric conducting (PEC) waveguide comprising the lens operates slightly above its cut-off frequency and has the same length but different cross-sectional dimensions. This allows controlling individually the propagation constant and the normalized characteristic impedance of each waveguide for the desired phase front at the lens output while Fresnel reflection losses are minimized. A complete theoretical analysis based on the waveguide theory and Fermat's principle is provided. This is complemented with numerical simulation results of two-dimensional and three-dimensional lenses, made of PEC and aluminum, respectively, and working in the terahertz regime, which show good agreement with the analytical work.
58 citations
"Quad-Band Polarization-Insensitive ..." refers background in this paper
...The numerical model assumes uniform plane-wave illumination on an infinite structure [11]....
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...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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