There are numerous dielectric property characterization techniques available in the microwave regime each with its own uniqueness, advantages and disadvantages. The two-port completely-filled waveguide (transmission line) technique is a robust measurement approach which is well suited for solid dielectric materials. In this case, the dielectric material can be relatively easily machined to fit inside the waveguide and the subsequent measurement of the scattering parameters of this two-port device renders the dielectric properties of the material filling the waveguide. However, this technique is not well suited for measuring the dielectric properties of granular and liquid materials. These materials are used in the production of various composites which are increasingly replacing the use of metals in many environments. If this technique is directly applied to these types of materials, several approximations either in the measurement apparatus or the formulation must be made. To overcome this problem, this paper describes a modification to this measurement technique utilizing two dielectric plugs which are used to house the granular or the liquid dielectric material. In this approach no approximation to the measurement apparatus is made while the presence of the plugs are fully accounted for in the derivations. Using this technique, the dielectric properties of cement powder, corn oil, antifreeze solution and tap water, constituting low- and high-loss dielectric materials (granular and liquid) were measured. In addition, the important issue of measurement uncertainty associated with this technique is also fully addressed. The issue of optimal choice of various measurement parameters is also discussed as it relates to the measurement uncertainty.


Electrical and Computer Engineering

Keywords and Phrases

S-Parameters; Antifreeze Solution; Cement Powder; Corn Oil; Dielectric Losses; Dielectric Measurement; Dielectric Plug-Loaded Two-Port Transmission Line Measurement; Dielectric Property Characterization; Granular Materials; High-Loss Dielectric Materials; Liquid Materials; Low-Loss Dielectric Materials; Measurement Apparatus; Measurement Parameters; Measurement Uncertainty; Microwave Measurement; Microwave Regime; Multiport Networks; Scattering Parameters; Tap Water; Composite Testing and Evaluation; Electromagnetic Formulation-Probe Development and Antennas; Material Characterization

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

File Type





© 1999 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Dec 1999