Packaging & EMI/RFI Shielding

The need for EMI/RFI shielding has never been greater than it is today. We are surrounded by RFemissions everywhere, constantly. Anyone who has looked at the screen of a high-frequency spectrum analyzer fitted with an antenna probe can verify just how cluttered the airwaves are in practically any environment. Yet everyone expects there electronic devices to operate flawlessly, regardless of the surrounding chatter.

Fortunately, a number of companies have been coming up with new solutions to help designers deal with the problem. The following are but a few examples of the products that are readily available to designers today for coping with EMI/RFI.

For use in demanding military, medical, industrial, and avionic applications, the CAR Series and VC1-IM Series index-matched ITO coatings on glass filters from Dontech (www.dontech.com) are designed for high-end displays to provide exceptional optical and electrically conductive properties. Utilizing the latest thin-film vacuum deposition technology, CAR Series (index-matched to air) and VC1-IM Series (index-matched to lamination coatings) optimize display contrast (for example, sunlight readability) while providing EMI/RFI shielding and/or transparent heating.

Dontech dielectrically enhanced ITO coating filter

The filters can be fabricated from a variety of glass substrates, such as chemically strengthened (soda lime, Corning Gorilla, or Asahi Dragontrail), borosilicate, fused silica, and optical glasses (for example, Schott nBk-7). Customization options include low photopic reflections and tightly toleranced resistances. The coatings offer AR coating reflections less than 0.4%, and ITO sheet resistances range from less than 1 Ω/sq. to 300 Ω/sq., with transmittances over 96%.

Pulse Electronics (www.pulseelectronics.com) recently introduced a 10GBASE-T press-fit integrated connector module (ICM) product family that “have a patented shielding system that prevents noise interference from adjacent ports, ensuring optimal data transmission,” according to Product Manager Muhammad Khan. “The ICMs are tuned to have excellent insertion and return loss performance over 10-gigabit frequencies.” The modules are designed to facilitate implementation of 10GBASE-T in large enterprises and cloud data centers.

Pulse Electronics 10GBASE-T press-fit integrated connector module

The press-fit RJ45 ICMs meet IEEE 802.3 specifications and are available in common industry configurations: 2 x 2, 2 x 4, 2 x 6, and 2 x 8. Using a press-fit pin provides a pressure contact with the printed circuit board, eliminating the need for wave soldering, and the products are qualified at leading 10GBASE-T PHY vendors, which enables system designers to eliminate extensive qualifications and accelerates time-to-market for their products.
When designing an electronic enclosure, engineers must be certain that all gaps, seams and openings are properly shielded. As chip speeds and operational frequencies increase, even the smallest gaps can allow unwanted electromagnetic and radio frequency interference to escape into the surrounding environment. To solve this extremely common problem, Leader Tech (www.leadertechinc.com) developed a comprehensive line of FSG fabric shielding gaskets.

Leader Tech FSG fabric shielding gaskets

The company offers 125 different sizes and profiles that are both lightweight and extremely easy to install. Each gasket is manufactured with a resilient polyurethane foam core and a unique, highly conductive nickel/copper ripstop outer fabric that exhibits a shielding effectiveness up to 115 dB when installed.

There are times when systems not designed for RFI protection need to have immunity added. For such instances, Select Fabricators has recently unveiled two new Select-A-Shield RF isolation pouches with a redesigned window-touchscreen and USB connectivity. They can be used to isolate wireless devices and view data without sending or receiving signals, thereby enhancing data security for mobile forensic applications.

Select Fabricators Select-A-Shield RF isolation pouches

The patent-pending window touch pouches offer high RF shielding performance of –80 dB at 1 GHz and large, nonglare touch screens made from double-layer conductive mesh to accommodates a wide variety of mobile devices. The pouches are made with conductive silver/copper/nickel material with a double rollover closure to ensure a tight isolation performance.  Conductive material will maintain shielding performance for hundreds of uses. The standard bags come in 6.25 x 10.25-in. and 9.5 x 12.625-in. sizes and custom size and configuration “Faraday bags” are also available.