Microwave absorbers are absorbers that absorb microwaves up to 100 GHz. They consist of materials whose surfaces have magnetic or electrical properties and attenuate discrete microwaves or broader microwave bands.
Absorbent material properties are achieved by manufacturers by varying the thickness and structure of the material. Microwave absorbers are made of cross-linked or lossy foams, elastomers or plastics with a permeability of 1. They are designed as flexible, plate-shaped pyramid and flat absorbers and have a reflection attenuation of more than 50 dB.
Microwave absorbers are available for narrowband frequency ranges or discrete frequencies and for broadband absorption. Those for discrete frequencies are called Tuned Frequency Absorbers or Resonance Absorbers and are elastomeric absorbers. The broadband microwave absorbers are cross-linked foam absorbers or cavity resonance absorbers. The usable frequency range is between 1 GHz and 20 GHz.