Magnetic Field Testing - Antenna Selection by Application
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.
Magnetic Field Testing Products
SAS-560
20 Hz - 2 MHz
This 5 1/4" (13.3cm) Loop Sensor is built for MIL-STD-461 low frequency magnetic field testing.
SAS-562B
10 KHz - 30 MHz
This 18" Active Loop Antenna comes with a matching network and preamplifier for magnetic field testing.
SAS-563B
1 KHz - 30 MHz
This 12" Broadband Loop Antenna with preamplifier is an excellent solution for shielding effectiveness and emissions testing.
SAS-563P
1 KHz - 30 MHz
This 12" (30 cm) Passive Shielded Loop Antenna is an excellent solution for shielding effectivness testing.
SAS-564
1 KHz - 30 MHz
Input handling capability up to 500 Watts, and rugged design make this Loop Antenna excellent for testing.
SAS-565L
20 Hz - 1 MHz
This Passive Shielded Loop Antenna is an excellent solution for both emissions and immunity testing at low frequencies.
SAS-565H
9 KHz - 30 MHz
This Passive Shielded Loop Antenna is an excellent solution for both emissions and immunity testing at high frequencies.
H-Field Rods
100 Hz - 30 MHz
When improved sensitivity is desired for magnetic field testing, the H-Field Rod is an alternative to traditional loop antennas.
Tripods and Mounting Adapters
Our tripods and antenna mounting adapters are specificly designed to meet the needs of any Test lab
RF Cables
up to 40 GHz
Our Low-Loss High-Frequency flexible cables are the preferred choice over standard cable types.
Magnetic Field Testing Resources
Magnetic Field Conversions
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.
Shielding Effectiveness Test Guide
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.
A Basic Bulk Current Injection Test Method
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.
Typical EMC Related Formulas
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.
Other Services
Product Showcase
Loop Antennas
- 20 Hz to 30 GHz
- Magnetic Field testing
- Three Year Warranty
Loop antennas are primarily used to measure the magnetic field strength at lower frequencies. The small size of these loop antennas has the advantage of convenience in handling, availability of a zero- response orientation, and a simple expression for the voltage produced by a given field strength.
Popular links
Additional Resource
Magnetic Field Conversions
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. [more...]
Contact Details
A.H. Systems, inc.
9710 Cozycroft Ave.
Chatsworth, CA 91311
P: (818) 998-0223
F: (818) 998-6892
E: Email