Nondestructive measurements of the resistivity of thin conductive films and the dielectric constant of thin substrates using an open-ended coaxial line

This paper presents a modified theory for the measurement of the surface resistivity of thin films, deposited on either thin or thick dielectric substrates; in addition the formulations for the measurements of thin dielectric substrates is derived. The reflection coefficient of a probe in contact with the surface is used to calculate the surface resistivity of the film or else the dielectric constant of the dielectric substrate. The expression giving the reflection coefficient in terms of the surface resistivity of a film on a thin substrate is developed by matching the electromagnetic fields at the aperture of the coaxial line. Experimental results of conductive thin films on thin substrates (indium tin-oxide thin film deposited on polyethylene substrates) and dielectric substrates without films are reported from DC to 4 GHz. The experimental results calculated with the derived expressions and the measured reflection coefficients are in agreement with surface resistivity values quoted by the manufacturer of the various test samples used.

[1]  Mohamed D. Abouzahra.  Automated wide-band surface resistivity measurements of resistive sheets , 1987, IEEE Transactions on Instrumentation and Measurement.

[2]  Liu Liping,et al.  Measurement of Dielectic Properties of Biological Substances Using Improved Open-Ended Coaxial Line Resonator Method , 1987, 1987 IEEE MTT-S International Microwave Symposium Digest.

[3]  E. Tanabe,et al.  A nondestructive method for measuring the complex permittivity of dielectric materials at microwave frequencies using an open transmission line resonator , 1976, IEEE Transactions on Instrumentation and Measurement.

[4]  S. S. Stuchly,et al.  Analysis of the Open-Ended Coaxial Line Sensors , 1990 .

[5]  Janis Galejs.  Antennas in Inhomogeneous Media , 1969 .

[6]  Renato G. Bosisio,et al.  An alternative explicit six-port matrix calibration formalism using five standards , 1988 .

[7]  Nathan Marcuvitz.  Waveguide Handbook , 1951 .

[8]  S. Evans,et al.  Dielectric measurements with an open-ended coaxial probe , 1987 .

[9]  D. K. Misra,et al.  A Quasi-Static Analysis of Open-Ended Coaxial Lines (Short Paper) , 1987 .

[10]  Kenneth R. Foster,et al.  Noninvasive electrical characterization of materials at microwave frequencies using an open-ended coaxial line: test of an improved calibration technique , 1990 .

[11]  F. E. Gardiol,et al.  Reflection of an open-ended coaxial line and application to nondestructive measurement of materials , 1981, IEEE Transactions on Instrumentation and Measurement.

[12]  D. Misra,et al.  An experimental technique for in vivo permittivity measurement of materials at microwave frequencies , 1990 .

[13]  E. C. Burdette,et al.  In Vivo Probe Measurement Technique for Determining Dielectric Properties at VHF through Microwave Frequencies , 1980 .

[14]  Maria A. Stuchly,et al.  Measurement of Radio Frequency Permittivity of Biological Tissues with an Open-Ended Coaxial Line: Part I , 1982 .

[15]  Devendra K. Misra,et al.  Static analysis of an open-ended coaxial line terminated by layered media , 1990 .

[16]  G. B. Gajda,et al.  Analysis of an open-ended coaxial line sensor in layered dielectrics , 1986, IEEE Transactions on Instrumentation and Measurement.

[17]  G. A. Watson.  A treatise on the theory of Bessel functions , 1944 .

[18]  M. Stuchly,et al.  Coaxial Line Reflection Methods for Measuring Dielectric Properties of Biological Substances at Radio and Microwave Frequencies-A Review , 1980, IEEE Transactions on Instrumentation and Measurement.

[19]  Maria A. Stuchly,et al.  On the Measurement Accuracy of the Tissue Permittivity in Vivo , 1983, IEEE Transactions on Instrumentation and Measurement.