Antenna Selection - Magnetic Field Testing

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.

Most common radiated immunity standards include IEC/EN 61000-4-3, MIL-STD 461 RS101/03/05, SAE J113/4, ISO 11451-2, ISO 11452-4/5 and CISPR 20. These standards require the use of several different antennas.