INSERTABLE WAVEGUIDE VERIFICATION STANDARDS FOR THE ELECTROMAGNETIC CHARACTERIZATION OF MATERIALS

A process is introduced to design and validate insertable rectangular-waveguide verification standards for the electromagnetic characterization of materials using the Nicolson-Ross-Weir method. Each insertable structure consists of a series of metal steps that acts as a surrogate material exhibiting smooth and predictable permittivity and permeability characteristics across the waveguide band. These known material properties can be used to assess the performance of material characterization systems. Since the verification standards are inserted into the waveguide in the same manner as samples under test, each step in the normal measurement procedure is duplicated. A specific example of an S-band verification standard is presented, with the standard fabricated using two different methods. The first standard is machined from a solid metal block while the second is constructed by metalizing a 3D printed polymer structure. Comparison of the predicted material parameters to those extracted from experimental data demonstrates the utility of the proposed insertable standards.