A Novel Sample Holder for S11 Calibration Using SOM for Dielectric Measurement in Liquids via the Cut-off Waveguide Reflection Method

In this study, a novel jig structure suitable for S11 calibration using SOM (short, open and reference material) termination was proposed as a preliminary step for dielectric measurement in liquids via the cut-off circular waveguide reflection method. Specifically, for realization of S11 calibration with reliable short termination, the inner diameter of the waveguide of the jig was set to be slightly larger than the inner diameter of the outer conductor of the coaxial line in order to ensure that the short element remains in contact with the outer conductor (ground plane) of the coaxial line due to its placement in the waveguide. S11 at the front of the sample was calibrated with SOM conditions using a jig with this structure and a jig for press-fitting a short round bar via a VNA (vector network analyzer) in the frequency band of 0.50 to 3.0 GHz. Pure water was used as the standard material, and S11 was measured with various liquids in the jig. These outcomes indicated the validity of S11 calibration method with the proposed structure.