A thin sheet specimen is inserted into the test fixture through a slot. The test fixture consists of a rectangular coaxial transmission line connected to a network analyzer and the slot goes through both the outer and inner conductors of the transmission line.
The insertion of the test specimen changes the transmission amplitude and phase measured by the network analyzer. An inversion algorithm converts the measured amplitude and phase into a corresponding real and imaginary sheet impedance at each frequency measured.
Resistive materials are used to absorb, reflect, or guide electromagnetic energy in a variety of applications. This test method is useful for evaluating the intrinsic properties of sheet materials, whether in small experimental batches or in high-volume production. Specifically, the slotted configuration of this device enables non-destructive evaluation of materials in a manufacturing setting as well as individual witness coupons.
