The challenges posed by EMI, RFI, and EMP have become increasingly significant, as these interferences can affect how sensitive electronic devices function. This may lead to data corruption, system failures, and even life-threatening situations in fields such as aerospace and healthcare. Thus, effective shielding is crucial for protecting electronic systems from such disruptions.

However, in order to ensure that equipment operates reliably and meets strict required standards, its effectiveness must be rigorously tested. In fact, comprehensive testing serves as a cornerstone in the development and implementation of good EMI, RFI, and EMP shielding design. Here’s why.

• Testing ensures compliance with regulations and requirements such as MIL-STD-461, MIL-STD-188-125, IEEE-299, 05, DoDICD/ICS 7-160, etc…
• It decreases potential service costs and warranty issues
• Aids in detection of possible negative interactions between electronic devices and electrical systems in a given environment
• Helps identify potential safety hazards

The Importance of Testing EMI/RFI/EMP Shielding Products

EMI/RFI/EMP shielding testing involves a series of evaluations designed to assess the effectiveness of materials and enclosures. Testing such products is important for a multitude of reasons that directly impact product performance, safety, and marketability. Some of these include:

In short, comprehensive testing processes not only ensure that EMI/RFI/EMP shielding products meet industry standards but also help uncover any vulnerabilities early in the development cycle.

How EMI/RFI/EMP Shielding Products Are Tested

Shielding effectiveness is measured through various types of tests, including open field tests, coaxial transmission line tests, shielded box tests, and shielded room tests.

Open Field Tests for EMI/RFI/EMP Shielding

Open field tests expose the shielding material to electromagnetic fields in an unobstructed outdoor environment or an indoor environment with a non-conductive construction, allowing  assessments across a wide frequency range of magnetic, electric, and planewave fields and EMP tests.  This test methodology is referred to as the “free space test” or an Open Area Test Site (O.A.T.S.).  Prior to testing, a frequency scan is performed of all environmental ambient noise from radio/TV stations, weather radar, machinery, etc. and nulled out to produce an electromagnetically clean test environment.

Coaxial Transmission Line Tests for EMI/RFI/EMP Shielding

Coaxial transmission line tests utilize a controlled setup where the shielded material is placed within or over a coaxial cable, allowing for transmitted signals to be accurately measured. The coaxial cable includes an inner conductor and an outer shield or device under test (DUT), a preliminary frequency scan is performed prior to the shield to calibrate and null out the cable resonance and reflections ensuring optimal control of testing conditions and repeatable results.

Shielded Box Tests for EMI/RFI/EMP Shielding

Shielded box tests involve placing an electronic device under test (DUT) inside a shielded box to prevent external electromagnetic interference when in operation.  Testing can also be performed to determine the shielding level of various EMI/RFI gaskets installed on the shielded box by placing an antenna inside the box and measuring the radiated emissions before and after EMI/RFI gasket installations.

 

Shielded Room Tests for EMI/RFI/EMP Shielding

Shielded room tests utilize two shielded rooms separated by a common wall in the middle. One room contains a radiating antenna while the other contains a receiving antenna and test equipment.  The common wall between the two shielded rooms holds a test fixture for installation of various shielding products to be tested.  This environment eliminates external ambient noise and allows for precise measurements of shielding effectiveness across a broad spectrum of frequencies.

The type of test conducted and antennas used depends on several factors, such as size, composition, frequency range, and the intended use of the shielding material. In some cases, other types of tests may be required.

 

Examples of MAJR Products’ EMI/RFI/EMP Product Testing

EMI & EMP Range Testing for Honeycomb Waveguide Panels

MAJR has recently tested a variety of Honeycomb Waveguide Panel configurations which include both Steel & Brass media with different mounting frames and product finishes as seen in the following tables. Our results have been organized into the following performance categories: Excellent, Very good, Good and Fair.

Tin Plated Steel Frame with Steel Honeycomb Waveguide Panel

This configuration provides excellent shielding, fair corrosion resistance and can be produced in moderate panel sizes up to 38” x 38” or 50“ x 24”.

Brass Frame with Brass Honeycomb Waveguide Panel

This configuration provides good shielding, excellent corrosion resistance and can be produced in large panel sizes up to 96 x 68”. 

Brass Frame with Painted Steel Honeycomb Waveguide Panel

This configuration provides very good shielding, very good corrosion resistance and can be produced in large panel sizes up to 96” x 68”.

 

Airflow Testing for Waveguide Ventilation Panels

MAJR Products has completed airflow testing on a majority of its standard aluminum honeycomb panel and media configurations. These configurations include the common .50” thick by .125” cell material which provides superior airflow while still meeting the waveguide beyond cutoff ratio required for high broadband attenuation. Other airflow tested configurations include slant cell oriented honeycombs and .25” thick honeycomb media for maximum airflow requirements.

MAJR Products Cares About EMI/RFI/EMP Testing

At MAJR Products, we prioritize the quality and reliability of our EMI/RFI/EMP shielding solutions. Our shielding products have undergone a rigorous testing process to ensure optimal attenuation for a variety of environments and project specifications. Order your products from a veteran-owned business committed to the highest standards. Get in touch with us today.