Historically, military forces all over the world used microwave absorbers to cut down high-frequency energy reflections. Over the course of time, the use of these materials has diversified so that now they are also used in many commercial applications including wireless LAN devices, electronic devices, wireless antenna systems, notebook computers, cellular phone base stations, and network switches and servers. If you are planning to use RF absorbers in your application, the following are the five types you must know about.
- Surface Wave Absorbers
Surface wave absorbers are the most heavily magnetically loaded absorber products that are custom designed to absorb microwave energy in many high-performance appliances without compromising on the features of elastomeric binders. They are designed to provide the highest loss of all absorbers. Most of the surface wave absorbers are used in metal surfaces for attenuating surface wave energy from 1 GHz up to 20 GHz.
- Tuned Frequency Absorbers
Resonant or tuned frequency absorbers offer great loss of reflection at a distinct frequency. They typically offer 20dB of attenuation and narrowband absorption from 1 GHz up to 40 GHz.
- Low Frequency Absorbers
These absorbers offer high-loss at sub-microwave frequencies and are made with magnetic particles with specific shapes. They show high permeability from 1 MHz up to 3 MHz.
- Cavity Resonance Absorbers
Cavity Resonance absorbers are designed to show high-loss inside a microwave chamber. They attenuate resonant frequencies, cavity oscillations, and harmonics. These absorbers attenuate high and normal angles of incidence at frequencies ranging from 1 GHz to 20 GHz.
- Reticulated Foam Absorbers
Reticulated foam absorbers are extremely lightweight and are conductive carbon stacked sheet absorbers, offering high loss at off-normal and normal angles of incidence. Reticulated foam absorbers are designed with a constant gradient coating, producing broadband reflection loss performance from 1 GHz to 20 GHz.