The PM20 and PM30 NAPTEX!R^ E-field radiation protection fabric, developed primarily for use as protective clothing, provides up to 40 dB reduction of electric field radiation when placed between radiating source and the user. It also can be used as shielding tarps and curtains to suppress unwanted EMI around sensitive instruments. This product is effective to over 50 GHz and is used as protective clothing in applications such as broadcasting, heat sealing and diathermy, where RF levels may exceed the IEEE C95.1 OSHA enforceable standard.
The typical shielding effectiveness of PM20 and PM30 is shown in Figure 1. From 10 kHz to 500 MHz, the test method consisted of a single layer of NAPTEX wrapped around an isotropic probe in a referenced field of 200 V/m. From 500 MHz to 20 GHz, the test method was MlL-STD-285. The graphical data represents a standard deviation of 3 dB (!sigma^ = 3). The breakdown threshold is !is greater than^ 2 W/!cm.sup.2^ at 680 kHz and !is greater than^125 W/!cm.sup.2^ at 2.3 GHz. These threshold values are preliminary because sufficient levels of RF energy have not yet been generated to cause arc-over or breakdown.
The material, which looks and feels similar to broadcloth, consists of a pure cotton wrap and a fill of polyester and stainless steel fibers. The material is available in flame retardent versions, which meet the NFPA 1975 standard on station/ work uniforms for firefighters.
The material can be fashioned into any type of wearable garment, as shown in Figure 2, and is currently available as full-body coveralls and as other products like EMI shielding curtains or covers. The PM20 is available in light blue, the PM30 raw material is available in olive green, and the coveralls are available in yellow. Other colors are available upon request. It may be repeatedly machine washed and dried or dry-cleaned and worn in total comfort.
Source Citation:"E-field fabric protects up to 40 dB." Microwave Journal 36.n1 (Jan 1993): 147(1). Academic OneFile. Gale. BROWARD COUNTY LIBRARY. 29 Aug. 2009
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