Title :
Complex permittivity measurements of moulding plastic using hybrid time and frequency methods
Author :
Elkhazmi, E.A. ; Abidin, M. N Zainal ; McEwan, N.J.
Author_Institution :
Dept. of Electr. & Electron. Eng., Bradford Univ., UK
Abstract :
An improved method of measuring complex permittivity using a coaxial line test cell is described. Only two wideband reflection measurements on the same short circuited cell, with and without the sample present, are required. A hybrid time and frequency domain method, using gating, allows both the adaptor discontinuities and the frequency dependence of the line resistance to be accurately characterised from the empty line measurement. From the second measurement, a transcendental equation for the permittivity is solved conventionally in frequency domain but using the time domain response to provide an ambiguity-free starting estimate. With proper inclusion of the discontinuity and resistance effects, measurements of low loss tangents can be undertaken
Keywords :
dielectric loss measurement; frequency-domain analysis; microwave measurement; permittivity measurement; plastics; time-domain analysis; adaptor discontinuities; ambiguity-free starting estimate; coaxial line test cell; complex permittivity measurements; hybrid time/frequency domain method; line resistance; low loss tangents; moulding plastic; short circuited cell; transcendental equation; wideband reflection measurements; Circuit testing; Coaxial components; Electrical resistance measurement; Frequency domain analysis; Frequency measurement; Permittivity measurement; Plastics; Reflection; Time measurement; Wideband;
Conference_Titel :
High Frequency Postgraduate Student Colloquium, 1997
Conference_Location :
Leeds
Print_ISBN :
0-7803-3951-7
DOI :
10.1109/HFPSC.1997.651654