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Measuring the Complex Permittivities of Plastics in Irregular Shapes.
Hsien-Wen Chao1, Hua-Hsuan Chen1, Tsun-Hsu Chang1
1Department of Physics, National Tsing Hua University, 101, Section 2, Kuang Fu Road, Hsinchu 300044, Taiwan.
Polymers
|August 28, 2021
Summary
This study measured the complex permittivity of six plastics in irregular shapes using the enhanced-field method (EFM). Results show good agreement with bulk materials, validating the hybrid model for microwave frequency analysis.
Area of Science:
- Materials Science
- Electromagnetics
- Microwave Engineering
Background:
- Accurate measurement of complex permittivity is crucial for microwave applications.
- Characterizing polymers in non-standard shapes presents a significant challenge.
- Existing methods often require precisely shaped samples.
Purpose of the Study:
- To develop and validate a method for measuring complex permittivity of irregularly shaped polymers at microwave frequencies.
- To compare experimental results with simulations using various models.
- To evaluate the suitability of the enhanced-field method (EFM) for non-ideal sample geometries.
Main Methods:
- Utilized the enhanced-field method (EFM) with a Teflon sample holder for irregularly shaped polymers.
- Employed a network analyzer to measure resonant frequencies and quality factors.
- Validated experimental data against simulations using a high-frequency structure simulator (HFSS) with layer, ring, and hybrid models.
Main Results:
- The hybrid simulation model (Z5R5) demonstrated the best agreement with experimental data.
- Complex permittivities were accurately determined for high density polyethylene (HDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), polypropylene (PP), Nylon, and thermoplastic vulcanizates (TPV).
- Measured permittivities for irregularly shaped samples closely matched values for bulk materials.
Conclusions:
- The enhanced-field method (EFM) combined with the hybrid simulation model is effective for characterizing the microwave complex permittivity of irregularly shaped polymers.
- This approach provides a reliable alternative for material characterization when precise sample shaping is not feasible.
- The findings support the use of this method for quality control and material selection in microwave applications.
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