Microwave Anechoic Chamber

Microwave Anechoic Chamber definition

The antenna test microwave anechoic chamber is a kind of non-echo area that is near Free Space in a certain area of the anechoic chamber, the Static Zone test environment, in which most types of radio testing can be performed.

When electromagnetic waves incident on the wall, ceiling, the ground, the vast majority of electromagnetic waves are absorbed, while transmission, and reflection is very small.

The microwave also has some of the characteristics of light, with the meaning of optical darkroom, it is named microwave anechoic chamber.

SA and metal shield for the formation of a special room, which provides man-made open “free space” conditions in the darkroom to do antenna, radar, and other wireless communications products and electronic products testing can be protected from clutter and improve the test equipment under test Accuracy and efficiency, with the increasing development of electronic technology, microwave anechoic chamber is more people to understand and apply.

Microwave anechoic chamber is to use a wave-absorbing material to create a closed space, so that you can create a pure electromagnetic environment in the darkroom, microwave anechoic material can be all-absorbing materials, the main material is polyurethane absorbing sponge SA (high-frequency use) In addition, the test of electromagnetic compatibility of electronic products, the frequency is too low will use ferrite absorbing materials.

The main working principle of a microwave anechoic chamber is based on the electromagnetic wave propagating from a low magnetic guide to a high magnetic guide in the medium. The electromagnetic wave is guided by the high magnetic permeability absorbing the material. Through the resonance, a large amount of radiation energy of the electromagnetic wave is absorbed, and then the electromagnetic wave energy is into heat.

The scope of the applications

Microwave anechoic chambers are mainly used for radiated radio disturbance (EMI) and radiation sensitivity (EMS) measurements. The size of the anechoic chamber and the selection of RF absorbers are mainly determined by the dimensions and test requirements of the EUT.

Key Features

Frequency range: 30MHz ~ 18GHz Absorbing material reflection loss: 30MHz ~ 18GHz ≥ 15dB (Absorbing material using the composite absorbing material, that is, conical carbon sponge absorbing material affixed to the ferrite).

1. EMC darkroom performance (frequency range: 30MHz ~ 18GHz)
Absorbing material reflection loss: 30MHz ~ 18GHz ≥ 15dB

2. Darkroom shielding performance
Magnetic field 14KHz ≥ 75dB
150KHz ≥ 100dB
Electric field 200KHz ~ 50MHz ≥ 100dB
Plane wave 50MHz ~ 1GHz ≥ 100dB
Microwave 1GHz ~ 10GHz ≥ 100dB
10GHz ~ 18GHz≥90dB

Structure and composition

1. Shield room by the shielding shell, screen door, ventilation waveguide window, and various types of power filters and other components, the shield shell is usually welded.

2. The absorbing material has a strong absorption effect on space electromagnetic waves, showing small reflection and scattering of the electromagnetic wave. Absorbing material is divided into two kinds of flame retardant and flame retardant, flame retardant was nonwoven cloth, and polyurethane soft.

Single-layer ferrite sheet, the working frequency range 30MHz-1000MHz; Conical carbon sponge absorbing material: Conical carbon sponge absorbing material is made of polyurethane foam infiltrated in a carbon gel solution. Has good flame-retardant properties.

3. Other:

The main signal transmission board, turntable, antenna, and monitoring system.
Microwave darkroom is mainly used in quiet zone size, reflection level (static), inherent radar cross-section, cross-polarization, and other parameters.