The shielding cavity loaded with electronic equipment inside has a high Q value and is in overmode at relatively high frequency as a reverberation chamber (RC), but it does not have stirrers or paddles. However, the electromagnetic environment in the cavity is similar to that in the reverberation chamber working in frequency stirring mode or source stirring mode because of the certain bandwidth of the electronic equipment and the movement of the portable electronic equipment. Therefore, the electric field in the cavity can be predicted based on the theory of reverberation chamber. In order to predict the electric field in a given shielding cavity after loading additional electronic equipment, the determination method of the Q value of the cavity and the absorption cross section (ACS) of the electronic equipment, the influence of the ACS on the Q value of the cavity, and the relationship between the Q value and electric field are analyzed Firstly, the ACS and radiated emission power of the loading electronic equipment are measured in the RC. Then, the Q value of the cavity with the electronic equipment loaded inside is calculated by the known Q value of the cavity without the electronic equipment and the ACS of the electronic equipment. Finally, the electric field in the cavity loaded with electronic equipment is estimated by using the calculated Q value of the loaded cavity and the measured radiated emission power of the electronic equipment. The experimental results verify the effectiveness of the prediction method.
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