EMI/RF Shielding Honeycomb Panels

EMI/RF Shielding Honeycomb Panels for High-Performance Ventilation Systems

Electromagnetic interference and radio-frequency interference can threaten the performance of sensitive electronic systems, communications equipment, and protected facilities. At the same time, many facilities require continuous airflow for ventilation and environmental control. EMI/RF shielding honeycomb panels provide a practical solution by supporting ventilation while helping attenuate electromagnetic energy.

Indy Honeycomb manufactures robust metallic honeycomb panels for EMI/RF shielding applications, including ventilation systems used in HEMP-hardened facilities. Each panel combines a welded steel honeycomb core with a durable metal frame. The complete assembly is vacuum brazed at approximately 1,800°F to create strong, reliable joints throughout the panel.

This specialized manufacturing process supports the structural integrity, shielding performance, and installation durability required for demanding projects.

What Is an EMI/RF Shielding Honeycomb Panel?

An EMI/RF shielding honeycomb panel is a metallic assembly made from many small, conductive cells contained within a structural frame. Its cellular design creates open pathways through which air can pass while helping limit the transmission of electromagnetic and radio-frequency energy.

This combination makes metallic honeycomb particularly useful where a protected enclosure or hardened facility requires ventilation. Instead of completely sealing an airflow opening, engineers can incorporate a properly designed honeycomb panel into the ventilation system.

The dimensions of the cells, core depth, metal type, frame design, and manufacturing method all contribute to the finished panel’s performance. For this reason, EMI shielding honeycomb should be manufactured to match the technical and dimensional requirements of the specific installation.

Designed for HEMP-Hardened Ventilation Systems

HEMP, or high-altitude electromagnetic pulse, can produce electromagnetic energy capable of affecting electrical and electronic systems. HEMP-hardened facilities are designed to reduce that risk through carefully engineered shielding, grounding, entry-point protection, and other protective measures.

Ventilation openings require particular attention because they create necessary penetrations in the protected structure. An EMI/RF shielding honeycomb panel can be incorporated into an air-handling opening to support airflow while helping maintain the shielding effectiveness of the facility.

Indy Honeycomb has developed a robust process for manufacturing these panels. The company can tailor the honeycomb and frame configuration to project requirements, helping customers obtain components suited to new construction, facility improvements, and specialized shielding installations.

Welded and Vacuum-Brazed Panel Construction

The integrity of an EMI/RF shielding panel depends on more than its external dimensions. Reliable electrical and structural continuity must exist throughout the honeycomb core and between the core and its frame.

Indy Honeycomb begins by assembling a welded steel honeycomb core with a metal frame. The panel is then heat-treated in a vacuum furnace at approximately 1,800°F. During this brazing process, a molten nickel-based alloy is introduced into the joints and honeycomb cell nodes.

Vacuum brazing helps create consistent bonds throughout the assembly. It also supports panel strength and performance by joining areas that may be difficult to address through conventional welding alone.

Because the brazing operation occurs at such a high temperature, the panels are also less likely to be damaged by the heat generated when they are welded into an installation. This can be an important benefit for contractors and fabricators integrating EMI shielding panels into larger ventilation assemblies or structural systems.

Available Honeycomb Core Configurations

Indy Honeycomb manufactures EMI/RF shielding cores in stainless steel and mild steel. Available configuration ranges include:

Materials: Stainless steel or mild steel
Cell size: Up to 5/8 inch
Cell-wall thickness: Up to 0.010 inch
Cell depth: Up to 3.25 inches
Panel length and width: Up to 42 by 42 inches

These options allow the honeycomb configuration to be selected according to the panel’s shielding, airflow, structural, and dimensional requirements.

Cell size and depth are especially important considerations. Smaller or deeper cells may be appropriate for certain shielding objectives, while the total open area of the panel influences airflow. Final specifications should therefore be based on the complete system design rather than panel dimensions alone.

Flexible Steel Frame Options

The frame holds the honeycomb core in position and enables the panel to be incorporated into its final installation. Indy Honeycomb offers frames with the following capabilities:

Stainless steel or mild steel construction
Frame thicknesses beginning at 0.125 inch
Length and width dimensions up to 42 by 42 inches
Flexible configurations tailored to the project
Ability to weld multiple panels into larger assemblies

The option to join individual panels is valuable for projects requiring shielding across openings larger than the maximum dimensions of a single unit. Custom frame configurations can also simplify installation by accounting for the surrounding structure, attachment method, and layout of the ventilation system.

EMI/RF Shielding Performance

A sample Indy Honeycomb panel was tested in accordance with MIL-STD-125-188. The test panel achieved average attenuation of 130 dB, with a worst-case shielding effectiveness point of 97 dB.

The tested panel had the following construction:

Stainless Steel 304 honeycomb and frame
3/8-inch hexagonal cell size
2-inch cell depth
0.125-inch-thick L-shaped frame
Overall dimensions of 24 by 24 inches
Welded and brazed honeycomb-to-frame assembly

These results demonstrate the potential shielding performance of a properly manufactured metallic honeycomb assembly. Actual results for a finished installation can depend on its selected configuration, interfaces, mounting method, surrounding structure, and overall shielding-system design.

Corrosion Protection and Finishing

Indy Honeycomb recommends painting or plating EMI/RF shielding panels to help improve performance and prevent corrosion. The appropriate finish will depend on the panel material, installation environment, electrical requirements, and project specifications.

Finishing should be considered early in the design and procurement process. This helps ensure compatibility between the protective coating, installation method, required electrical continuity, and long-term operating conditions.

Why Work With Indy Honeycomb?

Since 1996, Indy Honeycomb has focused on making metallic honeycomb easy to buy. The company serves more than 150 OEM and MRO customers and emphasizes rapid response, technical competence, accurate documentation, professional service, and consistent product quality.

Indy Honeycomb’s capabilities include EMI/RF shielding, engine seal honeycomb, structural metallic honeycomb, custom honeycomb applications, machining, waterjet cutting, milling, turning, and wire EDM. Its ISO 9001 and AS9100 quality systems further support customers with demanding product and certification requirements.