Comparison between transfer impedance and shielding effectiveness testing

Transfer impedance and shielding effectiveness testing was performed on a set of joint surfaces over the frequency range of 10 MHz to 1 GlrIz. The joint surfaces consisted of a set of plates and were: (1) a 6% inch outside diameter ring with a 4!/4 inch inside diameter; and (2) a 51/2 inch diameter disk. The plates were manufactured from !44 inch thick 6061-T6 aluminum and tin plated. The electromagnetic bonding was obtained using .040 inch thick zinc plated steel washers sandwiched between the plates and held in place with 6-32 screws on a 51/4 inch diameter ring. The number of screws and washers used were 2, 4 and 8 where the screws and washers were evenly spaced during each test.