Basic classification of anechoic chamber

Anechoic room Generally speaking, there are three testing places for radiation testing, namely, full anechoic room, semi-anechoic room and open field. The radiation tests conducted in these three test sites can generally be considered as conforming to the propagation law of electromagnetic waves in free space. Open Area Test (OAT) is an oval or circular test site, which is flat, empty, with uniform conductivity and no reflector. The ideal open space has good conductivity and infinite area. The signal received by the receiving antenna will be the sum of the direct path signal and the reflected path signal between 30 MHz and 1000 MHz. However, in practical application, although good grounding conductivity can be obtained, the area of the open field is limited, which may lead to the phase difference between the transmitting antenna and the receiving antenna. In the launch test, the use of open field is the same as that of semi-anechoic chamber.