The strength of the magnetic component of the electromagnetic field is typically measured with Loop antennas. The design of loops varies with the application and frequency range. In most cases the loops are electrostatically shielded by enclosing the wire turns inside a tubular conducting shield, which is broken at the some point around the periphery to prevent the shield acting as a shorting turn.
Loop are used primarily at low frequencies from a few hertz to tens or hundreds of KHz. For example the MIL-STD 462 N3 RE01 (30 Hz to 30 KHz) and RE04 (20 Hz to 50 KHz) test specify the use of a 13.3cm diameter loop over these frequencies. Larger loops but with areas of less than 1 square meter, are used for example to measure field strengths from 100 KHz to 30 MHz in accordance with VDE 0877 pt2. Such measurements are called for in VDE 0871/EN55011 in connection with industrial, scientific and medical (ISM) equipment.
The A.H. Systems' set of H-Field Rods provide an accurate standard for magnetic field testing. The rods are available individually or in a set of four to cover the frequency range of 100 Hz to 30 MHz. For those situations when improved sensitivity is desired in magnetic field testing, the H-Field Rod is an effective alternative to traditional loop antennas. One amplifier pre-assembled to a metallic ground plane covers the entire frequency range and can be used with any or all of the H-Field Rod elements.
Here are our two categories of antennas for magnetic field testing Loop Antennas or H-Field Rod Antennas.
Formulas and Calculations
Download our easy to use conversion tables for common magnetic field measurement units. With magnetic field testing sometimes it becomes necessary to convert from one unit of measure to another. This magnetic field conversion chart provides the conversion relationship between different types of magnetic field units.
Test Guide
Just as interference testing requires RF enclosures, isolation systems in turn need their own testing. This document reviews some of the issues and considerations in testing RF enclosures.
Test Guide
Here is an example of bulk current injection (BCI) test. Bulk current injection testing is to confirm that RF signals, when coupled onto interconnecting cables and/or power supply lines, will not cause degradation of performance or deviation from specifications of the equipment under test.
Formulas and Calculations
This Tech. Note covers frequently used conversion factors, how they are derived, and why they are used. If you need to convert from one series of units to another for any reason, this is the tech. note for you.