There are three factors causing the electromagnetic interference: interference source, coupling path and sensitive material.
The essential requirement of slip ring design is to make its structure close to transmission lines. At the same time, it is also characteristic of function and performance as excellent as lines. For transmission lines, they feature a good anti-interference capability. Likewise, the electrical slip ring design also takes the electromagnetic interference into account. For the electrical part, where space is limited, it is prone to confront more intricate EMI with varied signals, complex signal combinations and wide spectrum.
When designing an electrical slip ring, the way of anti-interference design is to cut out or attenuate the coupling paths between signals. Coupling paths can be divided into two kinds: conduction coupling and radiation coupling. However, in practical application, the coupling path of electromagnetic interference is intricate, which contains both conduction and radiation coupling. The latter is more obvious in the factors of designing slip rings.