Vol. 91

Front:[PDF file] Back:[PDF file]
Latest Volume
All Volumes
All Issues

An Accurate Complex Permittivity Method for Thin Dielectric Materials

By Ugur Cem Hasar and O. Simsek
Progress In Electromagnetics Research, Vol. 91, 123-138, 2009


A promising microwave method has been proposed to accurately determine the complex permittivity of thin materials. The method uses amplitude-only scattering parameter measurements at one frequency for this purpose. It resolves the problems arising from any offset of the sample inside its cell in complex reflection scattering parameter measurements and from any uncertainty in sample thickness in transmission scattering parameter measurements. The method determines unique permittivity since, for thin samples, multi-valued trigonometric terms can be linearized. It uses higher order approximations to extract highly accurate permittivity values. It works very well in limited frequency-band applications or for dispersive materials since it is based upon point-bypoint or (frequency-by-frequency) measurements. For validation of the method, we measured the complex permittivity of two thin polytetrafluoro-ethylene (PTFE) samples.


Ugur Cem Hasar and O. Simsek, "An Accurate Complex Permittivity Method for Thin Dielectric Materials," Progress In Electromagnetics Research, Vol. 91, 123-138, 2009.


    1. Chen, L. F., et al., Microwave Electronics: Measurement and Materials Characterization, JohnWiley & Sons, West Sussex, England, 2004.

    2. Hebeish, A. A., et al., "Factors affecting the performance of the radar absorbant textile materials of different types and structures," Progress In Electromagnetics Research B, Vol. 3, 219-226, 2008.

    3. Chung, B. K., "Dielectric constant measurement for thin material at microwave frequencies," Progress In Electromagnetics Research, PIER 75, 239-252, 2007.

    4. Murata, K., A. Hanawa, and R. Nozaki, "Broadband complex permittivity measurement techniques of materials with thin configuration at microwave frequencies," J. Applied Phys., Vol. 98, 084107-1-084107-0, 2005.

    5. Decreton, M. C. and F. E. Gardiol, "Simple non-destructive method for the measurement of complex permittivity," IEEE Trans. Instrum. Meas., Vol. 23, 434-438, 1974.

    6. Zhang, H., S. Y. Tan, and H. S. Tan, "An improved method for microwave nondestructive dielectric measurement of layered media," Progress in Electromagnetics Research B, Vol. 10, 145-161, 2008.

    7. Olmi, R., et al., "Thickness-independent measurement of the permittivity of thin samples in the X band," Meas. Sci. Technol., Vol. 13, 503-509, 2002.

    8. Baker-Jarvis, J., et al., "Analysis of an open-ended coaxial probe with lift-off for nondestructive testing," IEEE Trans. Instrum. Meas., Vol. 43, 711-718, 1994.

    9. Ghodgaonkar, D. K., V. V. Varadan, and V. K. Varadan, "Free-space measurement of complex permittivity and complex permeability of magnetic materials at microwave frequencies," IEEE Trans. Instrum. Meas., Vol. 39, 387-394, 1990.

    10. Hock, K. M., "Error correction for diffraction and multiple scattering in free-space microwave measurement of materials," IEEE Trans. Microw Theory Tech., Vol. 54, 648-659, 2006.

    11. Hasar, U. C., "A microcontroller-based microwave measurement system for permittivity determination of fresh cement-based materials," Proc. IEEE Instrumentation and Measurement Technology Conf. (IMTC'07), 2007.

    12. Rubinger, C. P. L. and L. C. Costa, "Building a resonant cavity for the measurement of microwave dielectric permittivity of high loss materials," Microwave Opt. Tech. Lett., Vol. 49, 1687-1690, 2007.

    13. Baker-Jarvis, J., E. J. Vanzura, and W. A. Kissick, "Improved technique for determining complex permittivity with the transmission/reflection method," IEEE Trans. Microw. Theory Tech., Vol. 38, 1096-1103, 1990.

    14. Sarabandi, K. and F. T. Ulaby, "Technique for measuring the dielectric constant of thin materials," IEEE Trans. Instrum. Meas., Vol. 37, 631-636, 1988.

    15. Kenneth, E. D. and L. J. Buckley, "Dielectric materials measurement of thin samples at millimeter wavelengths," IEEE Trans. Instrum. Meas., Vol. 41, 723-725, 1992.

    16. Chung, , B. K., "A convenient method for complex permittivity measurement of thin materials at microwave frequencies," J. Phys. D.: Appl. Phys., Vol. 39, 1926-1931, 2006.

    17. Challa, R. K., et al., "Permittivity measurement with a non-standard waveguide by using TRL calibration and fractional linear data fitting ," Progress In Electromagnetics Research B, Vol. 2, 1-13, 2008.

    18. Ness, J., "Broad-band permittivity measurements using the semiautomatic network analyzer," IEEE Trans. Microw. Theory Tech., Vol. 33, 1222-1226, 1985.

    19. Hasar, U. C., "Two novel amplitude-only methods for complex permittivity determination of medium-and low-loss materials," Meas. Sci. Techol., Vol. 19, 055706-055715, 2008.

    20. Hasar, U. C. and C. R. Westgate, "A broadband and stable method for unique complex permittivity determination of low-loss materials," IEEE Trans. Microw. Theory Tech., Vol. 57, 471-477, 2009.

    21. Hasar, U. C., "A fast and accurate amplitude-only transmission reflection method for complex permittivity determination of lossy materials ," IEEE Trans. Microw. Theory Tech., Vol. 56, 2129-2135, 2008.

    22. Hasar, U. C., "Simple calibration plane-invariant method for complex permittivity determination of dispersive and nondispersive low-loss materials," IET Microw. Antennas Propag., 2009.

    23. Hasar, U. C., "Elimination of the multiple-solutions ambiguity in permittivity extraction from transmission-only measurements of lossy materials," Microw. Opt. Technol. Lett., Vol. 51, 337-341, 2009.

    24. Balanis, C. A., Advanced Engineering Electromagnetics, John Wiley & Sons, New Jersey, NJ, 1989.

    25. Abramowitz, M. and I. A. Stegun (eds.), Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, 17-18, Dover Publications, New York, NY, 1972.

    26. Press, W. H., et al., Numerical Recipes in C: The Art of Scientific Computing, Ch. 9, Cambridge University Press, New York, NY, 1992.

    27. Baker-Jarvis, J., "Transmission/reflection and short-circuit line permittivity measurements," Natl. Inst. Stand. Technol., 1341, Boulder. CO. Tech., July 1990.

    28. Engen, G. F. and C. A. Hoer, "Thru-reflect-line': An improved technique for calibrating the dual six-port automatic network analyzer ," IEEE Trans. Microw. Theory Tech., Vol. 27, 987-993, 1979.

    29. Von Hippel, A. R., Dielectric Materials and Applications, John Wiley & Sons, New York, NY, 1954.