Cable Shielding to Minimize Electromagnetic Interference

Anke Fröbel
Cottbus University of Technology, Germany
Wrocław University of Technology, Poland

Abstract - A cable shield is necessary to prevent emission of electromagnetic waves from the cable respectively to protect data and signal conductors from external electromagnetic interference (EMI). The effectiveness of a cable shield installation depends on the kind of EMI to be shielded and the type of termination at both
ends. This paper depicts the different types of cable shielding. Moreover shielding effectiveness is analyzed.

I. INTRODUCTION

Electromagnetic shielding reduces, or rather prevents coupling of undesired radiated electromagnetic energy in electrical equipment. It is established over a large part of the electromagnetic spectrum from DC to microwave frequencies. In general, shielding is produced by insertion of a metallic barrier in the path of electromagnetic waves between the source of the radiation and the device which is supposed to be protected. The shielding may be applied at the source (if the source is known) or at the susceptible equipment. Fig.1. illustrates the two modes of shielding. Cable shielding is commonly used for data and signal cables. The design of cable shielding and grounding is important for the reduction of electromagnetic interference. Each application requires individual considerations given that parameters such as cable lengths, noise frequency, signal frequency and cable termination methodology impact the final result. Improperly make the problem worse. Figure 1. Modes of shielding: Shielding the source of noise or shielding the susceptible equipment.

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