Low-pass and high-absorption electromagnetic functional layer

Abstract

The invention discloses a low-pass and high-absorption electromagnetic functional layer, which comprises a low-pass and high-resistance frequency selection surface and a wave absorption unit array, wherein the low-pass and high-resistance frequency selection surface comprises metal structure unit arrays which are etched on two surfaces of a dielectric substrate and are different in structure size; the periods p of the unit arrays are 10.0mm to 20.0mm; metal structure units have rotation symmetry; the frequency selection characteristics of the metal structure units are irrelevant to the polarized direction of an incident wave; the metal structure units on two surfaces are different in size; the wave absorption unit array is a periodic array which comprises square or round sheets which are fabricated by magnetic loss radar wave-absorbing materials or resistance type wave-absorbing materials; the wave absorption unit array has broadband wave absorption performance on a high-frequency band; the sizes of wave absorption units are smaller than those of the metal structure units; and each wave absorption unit is adhered to one side of each metal structure unit with a relatively small size of the low-pass and high-resistance frequency selection surface. The obtained material is small in insertion loss, small in thickness, flexible in design and low in cost.

Description

technical field [0001] The invention relates to the technical field of electromagnetic wave-transmitting materials and wave-absorbing materials, in particular to a low-pass and high-absorption electromagnetic functional layer. Background technique [0002] The electromagnetic functional layer that can efficiently transmit waves within the working frequency band and efficiently absorb waves outside the working frequency band has important application requirements in the fields of anti-jamming communication, electromagnetic protection, and electromagnetic stealth. At present, the design of wave-transmitting materials and wave-absorbing materials is relatively independent, and there is a lack of new electromagnetic materials with high transparency to in-band signals and high absorption of out-of-band signals. Most of the absorbing materials are based on the metal reflective backplane to design their absorbing performance. When the metal backplane is removed, the absorbing perfo...

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Problems solved by technology

Moreover, in the absence of a metal backplane, as the thickness continues to increase, due to the strong reflection caused by the mismatch between the absorbing material and the air impedance, its absorbing performance reaches saturation, and the absorption rate can only be maintained at about 80%.

The increase in the thickness of the absorbing material sharply deteriorates the band-pass characteristics outside the absorbing frequency band, resulting in significant absorption attenuation loss and reflection loss. Therefore, it is difficult to achieve high in-band transparency and out-of-band high absorption only by absorbing materials. electromagnetic functional layer

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