Ultra-Wideband and Wide-Angle Microwave Metamaterial Absorber

Abstract

In order to extend the performance of radar absorbing materials, it is necessary to design new structures with wideband properties and large angles of incidence which are also as thin as possible. The objective of this work, realized within the framework of the SAFAS project (self-complementary surface with low signature) is, then, the development of an ultra-wideband microwave absorber of low thickness. The design of such material requires a multilayered structure composed with dielectric layers, metasurfaces, and wide-angle impedance matching layers. This solution has been realized with on-the-shelf materials, and measured to validate the concept. At normal incidence, the bandwidth ratio, defined for a magnitude of the reflection coefficient below −10 dB, is 4.7:1 for an absorber with a total thickness of 11.5 mm, which corresponds to λ/7 at the lowest operating frequency. For an incidence of 60°, this bandwidth ratio is reduced to 3.8:1, but the device remains ultra-wideband.

Design of an Optical Transparent Absorber and Defect Diagnostics Analysis Based on Near-Field Measurement

“…Radar absorbing materials that convert electromagnetic wave incidents from any direction to thermal energy and then absorb them, and radar absorbing structures (RAS) that cancel waves through interference are used in various fields such as radar cross-section (RCS) reduction technology [ 1 , 2 , 3 , 4 ]. The RCS reduction technology is one of the most important stealth technologies in defense, and is applied as interference reduction technology for improving communication performance in complex wireless communication environments in the private sector [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ].…”

Circular ring shaped ultra-wideband metamaterial absorber with polarization insensitivity for energy harvesting

“…Comparing with the previous works [13]- [16], the proposed absorber shows wide and good absorption characteristics in the UWB region (4 to 13 GHz). Begaud et al [14] explained that though the absorber has good absorption characteristics compared to our work, the limitations is on the thickness (t=5 mm) i.e., the thickness is very high compared to our proposed work (t=1.6 mm).…”

“…These metamaterial absorbers are designed and tuned based on the lumped parameters [6]- [8]. Different metamaterial absorbers have been developed to suit specific applications, for instance, a microwave metamaterial is developed with frequency tunability for sensing applications [9], low-cost microwave multiband [10 [11]- [13], polarization insensitive absorbers [14], [15] are developed with ultra-thin absorbers [16] for electromagnetic interference (EMI)/electromagnetic compability (EMC) applications and stealth technology for military applications [17]. Designing EM absorbers which can harvest in the entire UWB band can be very useful for battery less applications.…”

Large-Period Multichannel Metagratings For Broad-Angle Absorption

“…While the GSTCs may yield the abstract surface impedance values required to realize absorption for a given (single) excitation, they do not guarantee the performance in the entire desired angular range. Consequently, extended angular response is obtained via sophisticated meta-atom geometries, devised using heuristic intuitive approaches combined with full-wave optimization [4]. Alternatively, improvement can be achieved by harnessing specialized (e.g., spatially dispersive) meta-atoms, but these are not always straightforward to translate into practical designs [3,5].…”