Designers use different materials to design jammers
EMC issues are often a reason for restricting the export of Chinese electronic products. This article mainly introduces the sources of EMI and some very specific suppression methods.
Electromagnetic compatibility (EMC) refers to "the performance of a device, device, or system that can operate in its own environment without causing strong electromagnetic interference with other devices in the environment (IEEE C63.12 1987) )” For wireless transceiver equipment, the use of a discontinuous spectrum may partially achieve EMC performance. However, many relevant examples also show that EMC cannot always do this. There are cell phone signal jammers between cell phones and medical equipment, which we call electromagnetic interference (EMI).
All electrical and electronic equipment will have intermittent or continuous voltage and current changes during operation. Sometimes the speed of change is still very fast. This causes electromagnetic energy to be generated between different frequencies or frequency bands, and the corresponding circuits emit this energy. In the surrounding area.
There are two ways for EMI to exit or enter the circuit: radiated and conducted signal radiation exits through slots, slots, openings, or other spaces in the housing; when the signal lines leave the enclosure coupling with the power lines, signal lines and control lines, open space The free radiation of the radio will cause interference, but it is different from the frequency band emitted by the jammer.
Strong EMI suppression is achieved through the combination of shell shielding and slot shielding. In most cases, the following simple principles can help achieve EMI shielding: reduce interferers; use shielding, filtering, or grounding to isolate and improve noise circuits EMI suppression, isolation, and low sensitivity to interference suppression capabilities of sensitive circuits should be the goals of all designers of circuits, and these results should be obtained early in the design phase.
For designers, the use of shielding materials is an effective way to reduce EMI. Nowadays, a variety of hull protection materials are widely used, from metal cans, thin sheets and aluminum tapes to spraying and coating on fabrics or conductive tapes (such as conductive paint and spray zinc wire, etc.), whether metal or plastic coating The coating has a conductive layer. Once the designer has determined that it will be used as the casing material, you can begin choosing gaskets.