The attenuations upon reflection and transmission were
measured using the coaxial cable method (the transmission
line method). The setup consisted of an Elgal (Israel) SET
19A shielding effectiveness tester with its input and output
connected to a Hewlett-Packard (HP) 8510A network analyzer
[24]. An HP APB-7 calibration kit was used to
calibrate the system. The frequency was either 1.0 or 1.5
GHz. The sample placed in the center plane of the tester
(with the input and output of the tester on the two sides of
the sample) was in the form of an annular ring of outer
diameter 97 mm and inner diameter 29 mm. Silver paint was
applied at both inner and outer edges of each specimen and
at the vicinity of the edges to make electrical contact with
the inner and outer conductors of the tester [24]. The sample
thickness was measured for each specimen, but it was
around 4.3 mm.