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. 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 a specified data-reduction algorithm is used to calculate permittivity and permeability. If the material is nonmagnetic, a different algorithm is used to calculate permittivity only.
Design calculations for microwave and millimeter-wave components require the knowledge of values of complex permittivity and permeability at operating frequencies. This test method is useful for evaluating experimental batch or continuous production materials used in electromagnetic applications. It may be used to determine complex permittivity only (in non-magnetic materials) or both complex permittivity and permeability simultaneously.
