Title :
EMI shielding measurements of conductive polymer blends
Author :
Shacklette, L.W. ; Colaneri, N.F.
Author_Institution :
Allied-Signal Res. & Technol., Morristown, NJ, USA
Abstract :
Shielding efficiencies for a number of blends containing a variety of conductive fillers, including intrinsically conductive polymers, have been measured in the near-field with a dual-chamber box and in the far-field with a transmission line fixture. Although all samples tested satisfied the classical good conductor approximation, most of them exhibited a cross-over from being electrically thin (thickness<skin depth) to being electrically thick (thickness>skin depth) over the frequency range of interest, 1 MHz to 3 GHz. The theoretical relations for both near-field and far-field shielding which are prevalent in the literature do not accurately describe this region of cross-over. Expressions are defined that describe the behavior accurately over the entire range of interest. Far-field shielding efficiencies as high as 70 dB at 1 GHz were measured for purely organic composites consisting of an intrinsically conductive polymer dispersed in a thermoplastic matrix
Keywords :
conducting polymers; electric variables measurement; electromagnetic interference; filled polymers; microwave measurement; 1 GHz; 1 MHz to 3 GHz; EMI shielding measurements; conductive fillers; conductive polymer blends; dual-chamber box; electrically thick samples; electrically thin samples; far-field; intrinsically conductive polymers; near-field; purely organic composites; skin depth; thermoplastic matrix; transmission line fixture; Conductivity measurement; Conductors; Dispersion; Electromagnetic interference; Fixtures; Frequency; Polymers; Testing; Transmission line measurements; Transmission line theory;
Conference_Titel :
Instrumentation and Measurement Technology Conference, 1991. IMTC-91. Conference Record., 8th IEEE
Conference_Location :
Atlanta, GA
Print_ISBN :
0-87942-579-2
DOI :
10.1109/IMTC.1991.161543