The function of electromagnetic shielding cover: Simply speaking, there are basically two, one is to prevent external radiation interference, and the other is to shield external radiation interference; the more complicated point is to prevent external electric, magnetic or electromagnetic fields from interfering with internal devices or to avoid equipment The influence of the electromagnetic field on the outside, the device is placed in a closed or nearly closed metal shell or metal mesh cover.
Here comes the key question of custom electromagnetic shielding: 1. Is the size of the electromagnetic shielding cover correct? The electromagnetic wave in the electromagnetic shield can cause the electromagnetic oscillation of the metal and affect the normal operation of the circuit. Therefore, the appropriate shield size should be selected. Attention should be paid to the design: increase the length-to-width ratio of the electromagnetic shield and try to avoid square shields.
2. Is the material of the electromagnetic shielding cover correct? Commonly used shielding materials are materials with high conductivity, such as copper plate, copper foil, aluminum plate, aluminum foil, steel plate or metal coating, conductive coating, etc. Magnetostatic shielding is mainly used to prevent the influence of electrostatic field, such as the protection of small instrument or device interference, using copper and aluminum compact shell as shielding cover. Low-frequency electromagnetic shielding interference, using iron or beryllium molybdenum alloy and other magnetic materials to make the shell.
3. Whether the electromagnetic shielding cover is grounded or in good contact If the shielding cover is not in close contact with the shielding template, it will sometimes open and short-circuit. This behavior is a switching effect. And any metal, if it is not completely grounded, it is a radiator, and coupled with the switching effect between the electromagnetic shield and the shielding module, the radiation spurious will be strengthened, and there is a risk of exceeding the standard.
4. Is the distance between the electromagnetic shielding cover and the device sufficient? As the distance between the electromagnetic shielding cover and the matching component is too close, the signal will deteriorate due to electromagnetic interference and electromagnetic compatibility caused by interference electromagnetic waves.