EMC High Frequency Test Table

The frequency of the maximum difference between the test benches of different materials is the same, which is between 700~900 MHz.   

     From the formula for calculating the normalized field attenuation, it can be obtained:

     VR = VT - AFT - AFR - ΔAFTOT - AN

Because the dielectric constant of foam is close to that of air and smaller than that of wood, the site attenuation data measured when using a foam table in a darkroom is similar to that of a non-test table. However, when a wooden table is used in the darkroom, there is a big difference between the measured site attenuation data and the data without a test table. Due to the large dielectric constant of the wooden table, the attenuation AN of the darkroom field using the wooden table in Figure 5 is larger, and the maximum measured level value VR measured by the receiver will decrease when the AFT, AFR, AND ΔAFTOT are constant.

     Therefore, when anechoic chambers use auxiliary facilities such as wooden tables or test tables made of other materials with large dielectric constants, the attenuation AN of the site will increase, resulting in a decrease in the electric field strength measured by the receiver, resulting in differences in the test results. Auxiliary equipment such as test tables is an inseparable part of the effectiveness of the test site, so it is recommended to choose materials with a small dielectric constant when selecting anechoic room auxiliary facilities, and to compare the measurement of site attenuation to ensure the consistency of the measurement results of each anechoic room.