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
More filters
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
2 citations
TL;DR: In this paper, a triple band frequency selective surface (FSS) is proposed to act as a bandstop filter at 1.92 GHz, 3.5 GHz and 5.64 GHz.
Abstract: This paper proposes a novel design of a triple band frequency selective surface (FSS) that acts as a bandstop filter at 1.92 GHz, 3.5 GHz and 5.64 GHz. The bandstop frequencies resemble to GSM, WLAN and WiMAX application bands respectively. The structure is polarization insensitive since its frequency response remains unaltered for both TE and TM modes of electromagnetic wave propagation. The main attractive feature of the structure is its highly stable response under oblique incident angle up to ±80° at both TE and TM polarizations. Surface current distribution and equivalent circuit modeling are presented to demonstrate the resonance characteristic of the FSS. The structure is compact with an overall unit cell area of 0.09λ 0.09λ, where λ is the wavelength corresponding to the lowest resonant frequency. The proposed structure is compared with other multi-bandstop FSS structures in literature to highlight its superior functionality in terms of stability under oblique incidence and compactness. A prototype comprising of 6 6 array of the proposed unit cell is fabricated and the measured results are in good agreement with the simulated results.
1 citations
TL;DR: In this paper , a simple and compact terahertz frequency selective surface (FSS) with high selectivity is presented for cases of normal incidence, which is implemented by mapping the lumped components of a microwave filter topology circuit with two transmission zeros to structures of the FSS; the mapping is realized by slotting a cross-shaped aperture in the grid.
Abstract: Abstract A simple and compact terahertz frequency selective surface (FSS) with high selectivity is presented for cases of normal incidence. Guidelines for the design along with the operation mechanism are presented in detail from the view of an equivalent circuit. The design is implemented by mapping the lumped components of a microwave filter topology circuit with two transmission zeros to structures of the FSS; the mapping is realized by slotting a cross-shaped aperture in the grid. An intensive study on the equivalent circuit model predicts the existence of transmission zeros and poles. It can afford two transmission zeros and two transmission poles ranging from 350 GHz to 450 GHz with a band separation of 1.05 and 1.07, thereby exhibiting fast roll-off characteristics. The two transmission zeros can be controlled independently by simply changing the structure parameters of the unit cell. The proposed FSS is superior in terms of roll-off rate as well as the balance between selectivity and overall thickness. The measured results of the prototype are consistent with the simulation results, which validates the robustness of the design.
1 citations
04 Nov 2022
TL;DR: In this article , a design method of using metamaterial radome to improve the antenna gain of mmWave radar is proposed, and the maximum gain of the microstrip antenna is increased from 6dBi to 19.7dBi.
Abstract: In this paper, a design method of using metamaterial radome to improve the antenna gain of mmWave radar is proposed. Based on this radome design, the maximum gain of the microstrip antenna is increased from 6dBi to 19.7dBi, and the maximum gain is increased by about 14dBi. At the same time, compared with the planar array antenna, the design has the advantages of compact size and simple design.
References
More filters
Book•
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]....
[...]
...FREQUENCY selective surface (FSS) is a synthesized metallic structure printed on a dielectric substrate for filtering electromagnetic (EM) wave [1]....
[...]
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]....
[...]
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]....
[...]
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]....
[...]
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]....
[...]
...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]....
[...]