4.1 Introduction

The approach taken in this book with regard to ordering and presenting information about the dozens of sensors, couplers, probes and antennas used in EMC measurement is to discuss them in groups that are defined by the manner in which they couple to the signals being measured. The different physical processes related to each type of coupling can thereby be appreciated and a practical insight gained into their operation which is reflected in the structure of the various test methods employing these devices.

Although this particular chapter concentrates on coupling devices used in conducted EMC testing, all the groups of sensors discussed in this book, including radiated emission and suscept-ibility antennas, are listed here to show the number of groups and to illustrate the range of sensors considered.

Sensors are grouped as follows:

Conducted emission and susceptibility tests (CE, CS)

• Direct connection devices

  • Line impedance stabilisation network (LISN)

  • 10 F feedthrough coupling capacitor

  • Injection transformers

  • High-impedance voltage probes

• Inductively coupled devices

  • Cable current probes

  • Cable current clamps

  • Surface current probes

  • Straight and spiral wire inductive coupling

  • Inductive loops around boxes

  • Ferrite wands or probes

• Direct electrostatic discharge

  • Handheld spark generators

Devices for radiated emission (RE) tests

• Radiated emission antennas

  • Long wire antenna

  • Monopoles (passive and active)

  • Tuned dipoles

  • Biconic dipoles

  • Log. conical spiral

  • Log. periodic

  • Standard horns

  • Ridged horns

  • Horn-fed dishes

  • LF magnetic loops

  • Ferrite-cored loops

  • Leakage probes

Devices for radiated susceptibility (RS) testing

• Free-field antennas

  • Short transmission lines

  • Long wire antenna

  • Biconic dipoles

  • Log. spirals and...