A Jig Structure Based on an Open-Ended Coaxial Line for S11 Calibration for Dielectric Measurement

An S
11
calibration method for jigs with conditions referred to as SOM (short, open and one type of reference material) termination and a novel jig structure for precise S
11
calibration using short termination are proposed. For this purpose, the inner diameter of the jig’s circular waveguide (sample holder) was made slightly larger than that of the outer conductor of the coaxial line to allow complete electrical contact. The results showed good agreement between the measured S
11
after calibration and the theoretical S
11
value. The permittivity was then estimated as an inverse problem via the electromagnetic analysis at frequencies of 0.10, 1.0 and 2.5 GHz from the S
11
values measured with various liquids in the jig after calibration. As a result, good agreement between both values showed the effectiveness of S
11
calibration with SOM termination using the proposed jig and the subsequent dielectric measurement method.