Metasurface Absorber for 24.125 GHz

Absorbing materials are essential for electromagnetic interference and compatibility (EMI/EMC) testing. The need for absorbing electromagnetic radiation is often satisfied with wide bandwidth pyramid foam absorbers, which can be expensive depending on the size of the testing environment. In this article we introduce a low-cost Salisbury screen absorber using metasurface concepts and implemented on FR-4 substrate, which is known to be low cost but have great variations in its dielectric properties. The unit-cell of the Salisbury screen consists of split ring resonator meta-particles. The fabricated Salisbury screen is measured and is shown to absorb up to 56 dB of the incident power with a bandwidth of up to 500 MHz. The Salisbury screen can absorb incident radiation within ±5 degrees from the normal, which may limit the applications of absorber of this design to normal and near normal incident radiation.