Effect Of Sample Properties On Short-Circuited Waveguide Measurements For Materials Characterization
Abstract
Microwave materials characterization measurements can be performed using a number of well-established approaches. One such approach, the filled transmission line approach featuring a short-circuited rectangular waveguide (SC-RWG) sample holder, is known to have sample placement restrictions related to measurement viability. This work focuses on this approach and addresses the measurement restrictions within the context of sample length and dielectric properties. The complex reflection properties, S11, of a sample placed in a SC-RWG sample holder are studied to quantitively define when a sample must be offset from the SC-end. The impact of the sample holder is also studied from a measurement perspective, effectively establishing a (magnitude-based) measurement threshold that quantifies when the total measured signal is affected by the presence of a sample and hence the complex reflection properties may be used for materials characterization. For cases where the impact of the sample on the measured signal does not exceed the measurement threshold, the sample must be assumed lossless and the phase of the response may be used to determine permittivity. This is true so long as the impact of the sample on the measured phase is greater than the phase resolution of the measurement equipment. Considering the impact of the sample holder (specific to this work), measurements indicate that samples of length λg/3 or greater (regardless of dielectric properties) do not require the offset.
Recommended Citation
A. Hook et al., "Effect Of Sample Properties On Short-Circuited Waveguide Measurements For Materials Characterization," IEEE Open Journal of Instrumentation and Measurement, Institute of Electrical and Electronics Engineers, Jan 2026.
The definitive version is available at https://doi.org/10.1109/OJIM.2026.3711321
Department(s)
Electrical and Computer Engineering
Publication Status
Open Access
Keywords and Phrases
filled transmission line; liquid measurements; materials characterization; microwave nondestructive testing; short-circuited rectangular waveguide
International Standard Serial Number (ISSN)
2768-7236
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 2026 The Authors, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution 4.0 License.
Publication Date
01 Jan 2026
