Simple design of thin and wideband circuit analogue absorber

The advent of negative index materials has spawned extensive research into metamaterials over the past decade. Metamaterials are attractive not only for their exotic electromagnetic properties, but also their promise for applications. A particular branch–the metamaterial perfect absorber (MPA)–has garnered interest due to the fact that it can achieve unity absorptivity of electromagnetic waves. Since its first experimental demonstration in 2008, the MPA has progressed significantly with designs shown across the electromagnetic spectrum, from microwave to optical. In this Progress Report we give an overview of the field and discuss a selection of examples and related applications. The ability of the MPA to exhibit extreme performance flexibility will be discussed and the theory underlying their operation and limitations will be established. Insight is given into what we can expect from this rapidly expanding field and future challenges will be addressed.

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“…[ 6 ] Modern designs of CA absorbers have achieved absorption at high angles of incidence [ 12 , 13 ] and over broad bands. [ 14 ] …”

Section: Resonant Absorbersmentioning

confidence: 99%

Metamaterial Electromagnetic Wave Absorbers

2012

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“…Circuit-analog absorbers are actually a variant of Jaumann absorbers. Whereas Jaumann absorbers contain uniform resistive sheets, circuit analog absorbers insert sheets consisting of periodic patterned circuits, also known as frequency selective surfaces (FSS), containing both conductive and resistive materials [3,10,11,12,13,14,15,16,17,18,19,20]. Figure 3 illustrates some common CAA circuit patterns.…”

Section: Types Of Absorbermentioning

confidence: 99%

Radar-cross-section reduction of wind turbines. part 1.

Brock¹,

Loui²,

McDonald³

et al. 2012

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In recent years, increasing deployment of large wind-turbine farms has become an issue of growing concern for the radar community. The large radar cross section (RCS) presented by wind turbines interferes with radar operation, and the Doppler shift caused by blade rotation causes problems identifying and tracking moving targets. Each new wind-turbine farm installation must be carefully evaluated for potential disruption of radar operation for air defense, air traffic control, weather sensing, and other applications. Several approaches currently exist to minimize conflict between wind-turbine farms and radar installations, including procedural adjustroents, radar upgrades, and proper choice of low-impact wind-farm sites, but each has problems with limited effectiveness or prohibitive cost. An alternative approach, heretofore not techoically feasible, is to reduce the RCS of wind turbines to the extent that they can be installed near existing radar installations. This report summarizes efforts to reduce wind-turbine RCS, with a particular emphasis on the blades. The report begins with a survey of the wind-turbine RCS-reduction literature to establish a baseline for comparison. The following topics are then addressed: electromagnetic model development and validation, novel material development, integration into wind-turbine fabrication processes, integrated-absorber design, and wind-turbine RCS modeling. Related topics of interest, including alternative mitigation techoiques (procedural, at-the-radar, etc.), an introduction to RCS and electromagnetic scattering, and RCS-reduction modeling techniques, can be found in a previous report.

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“…Achieving wideband absorption while maintaining a low profile has been a major problem in the field of electromagnetic (EM) wave control and manipulation since early days 1 – 4 . Even today, many applications require simple and thin absorbers exhibiting the widest absorption bandwidth, such as radar cross section reduction, EM compatibility, and wireless communications 5 – 9 . Unfortunately, bandwidth enhancement and thickness reduction is a pair of fundamental contradictory propositions for absorber designs, which has been mathematically illustrated by the Rozanov theory 10 .…”

Section: Introductionmentioning

confidence: 99%

Broadband and thin magnetic absorber with non-Foster metasurface for admittance matching

Mou

Shen

2017

Sci Rep

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One of the long-standing and challenging problems in microwave engineering is the realization of ultra-wideband absorption using extremely-thin structures. Magnetic material can facilitate thickness reduction for microwave absorbers but also bring inherent narrowband admittance matching conundrum originating from its frequency-dispersive permeability and high permittivity. In this paper, we propose a simple and yet effective solution based on the concept of admittance matching with non-Foster metasurface (NFMS). Building on this concept, an ultra-wideband and extremely-thin magnetic absorber is achieved, with a simple structure consisting of a conductor-backed magnetic sheet (CMBS) coated by a NFMS. The NFMS with negatively inductive susceptance can properly cancel its positively frequency-dispersive counterpart from the CMBS so that constructive interference near the absorber can be obtained over a wide frequency band. Furthermore, the NFMS will compensate the surface conductance required for maximum incident power dissipation. As an example, we demonstrate an absorber with one-frequency decade bandwidth and a thickness of only 1/255 wavelength at the lowest operation frequency. The proposed concept enables versatile admittance matching techniques using a single-layered and has the potential to be used in the development of interesting low-profile and broadband microwave devices.

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Simple design of thin and wideband circuit analogue absorber

Cited by 27 publications

References 6 publications

Metamaterial Electromagnetic Wave Absorbers

Metamaterial Electromagnetic Wave Absorbers

Radar-cross-section reduction of wind turbines. part 1.

Broadband and thin magnetic absorber with non-Foster metasurface for admittance matching

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