Simple Device for Electromagnetic Interference Shielding Effectiveness Measurement

The design, construction, and testing results of a simple flanged coaxial electromagnetic interference (EMI) shielding effectiveness (SE) tester are presented in this paper. This tester is a coaxial holder with uniform diameters that maintain 50 Ohm impedance throughout the length of the device. The ends of the tester are designed to directly attach 10 dB, 50 Ohm, attenuators with standard N-type connectors, which allow practical coupling of the device for installation and measurements. This device was primarily designed to over- come several shortcomings of the ASTM D4935-99 standard SE tester that besides having a relatively complex shape requires relatively large sample specimens for testing. Com- pared to the frequency band of operation, up to 1.5 GHz, of the ASTM D4935-99 standard coaxial EMI tester, the newly developed SE tester operates in a broader frequency range, the- oretically up to 18.2 GHz. The tester was calibrated and the SE of common and new materials was determined through several experiments. The SE results were validated with expected theoretical outcomes. Index Terms—carbon nanofiber composite, coaxial test holder, electromagnetic interference, reinforced polymer, shielding effectiveness.