A planar test specimen is placed in a focused beam test fixture, which consists of two horn and lens pairs connected to a network analyzer. Depending on the specimen’s size and the focused beam’s spot size, it is acceptable to mount the sample in a metal aperture wall to reduce leakage around the specimen.
This test fixture is used to measure the S-parameters of the test specimen, along with appropriate calibration standards. After the data are calibrated, a time-domain gate is applied, and the shielding effectiveness is calculated from the Port 1 to Port 2 transmission S-parameter magnitude.
Designs for microwave and millimeter wave components require knowledge of the shielding effectiveness of applicable materials at operating frequencies. This test method is useful for evaluating experimental batch or continuous production materials used in these electromagnetic applications.
