EMI Shielding for Telecom and 5G Hardware
5G EMI shielding uses conductive coatings on plastic housings, covers and internal cavity walls to control interference in radios, small cells and customer-premises equipment. Vacuum metalized films provide greater than 60 dB of attenuation at 0.5–25 microns thick, while nickel-, copper- or silver-based conductive sprays deliver 40–80 dB. Because 5G hardware operates at higher frequencies and packs more radios into less space than previous generations, enclosure-level shielding has become a first-order design concern rather than an afterthought.
Why 5G Hardware Is Harder to Shield
Three trends collide in 5G equipment. First, operating frequencies are higher — sub-6 GHz bands and, in some deployments, millimeter-wave bands. As frequency rises, wavelengths shrink, and the seams, vents and fastener openings in an enclosure become electrically larger. Gaps that were harmless in older equipment can behave like slot antennas, so continuous conductive coverage and well-managed joints matter more than ever.
Second, board density has increased. Massive-MIMO radios, beamforming front ends and high-speed digital baseband processing sit millimeters apart. Noise coupling between sections of the same product — not just emissions to the outside world — now drives shielding requirements, and coated housing cavities can partition subsystems without adding board-level cans everywhere.
Third, the radio has moved outdoors and onto street furniture. Small-cell housings must be lightweight, weatherable and visually unobtrusive, which pushes designers toward molded plastics that need a conductive layer to shield at all.
Where Coatings Fit in Telecom Equipment
Small-cell and radio housings
Molded ABS, ABS/PC or polycarbonate radomes and equipment housings can be selectively metalized: full shielding over the electronics cavity, with masked windows where antennas must radiate. Mueller’s EMI/RFI/ESD shielding coatings are applied with in-house fixtures so the shielded and open zones repeat precisely across production.
Internal partitions and covers
Coated internal covers and cavity walls isolate power supplies from RF sections and separate transmit chains from sensitive receivers. Because vacuum metalized films are under 2 microns, they can be added to existing internal parts without changing fits.
Customer-premises and edge equipment
Routers, gateways and edge-compute boxes combine multiple radios with fast digital logic in consumer-grade plastic enclosures. A conductive coating helps these products meet radiated-emissions limits while keeping housings light and inexpensive. Retrofits are common here: when a gateway fails pre-compliance testing late in development, coating the existing housing often resolves the failure without touching the board or the tooling.
Choosing Between Vacuum Metalizing and Conductive Spray
| Consideration | Vacuum metalized film | Conductive spray |
|---|---|---|
| Thickness | 0.5–25 microns | 1–2 mils (25–50 microns; up to 10 mils) |
| Attenuation | Greater than 60 dB | 40–80 dB |
| Coverage character | Extremely uniform film, ideal for tight tolerances | Controlled build in targeted areas; choice of nickel, copper or silver |
| Typical use | High-volume housings, internal covers, tight assemblies | Complex geometry, selective shielding, grounding provisions |
Many telecom products use both: a metalized housing for overall shielding, produced through Mueller’s functional vacuum metalizing line, with conductive spray on gasket lands or grounding pads where extra thickness improves contact.
Getting the Details Right at High Frequency
At 5G frequencies, execution details decide whether a coating performs to its potential. Continuity across the whole shielded cavity, low-impedance contact to the PCB ground, overlap at housing seams, and clean mask lines at antenna windows all contribute. Mueller builds part-specific fixtures in-house and coats substrates from ABS and polycarbonate to nylon, PET and 3D-printed parts, so prototype housings can be validated in the anechoic chamber before tooling is finalized. Attenuation is verified on coated samples rather than assumed from datasheets. Environmental durability also belongs in the conversation for outdoor small cells: the shielding layer sits on the interior of the sealed enclosure, protected from weather, while the exterior finish handles UV and moisture. With no minimum order quantity, pilot builds of 50 units run on the same process as full production, so the samples your EMC lab approves are genuinely representative of what ships.
Work with Mueller Coatings. From a 65,000 sq. ft. facility in East Bridgewater, Massachusetts, Mueller Coatings has been applying functional metal films since 1955 and finishes more than 50 million parts annually. Send your small-cell, radio or CPE housing drawings and request a quote to review shielding options with our applications team.
What attenuation can a coated plastic housing achieve?
Vacuum metalized films deliver greater than 60 dB of attenuation, and conductive spray coatings deliver 40–80 dB depending on chemistry and thickness. Real-world results also depend on seams, apertures and grounding, which is why enclosure design and coating should be planned together.
Can antenna windows be left unshielded?
Yes. Fixtures and masking define exactly where the conductive layer is applied, so radome zones and antenna apertures remain RF-transparent while the electronics cavity is shielded.
How large a housing can be vacuum metalized?
Mueller’s vacuum chambers accept parts up to 24 inches in diameter and 60 inches long, which covers most small-cell, radio and enclosure components.
