Artificial dielectrics : characteristics at low and microwave frequencies
Department of Electrical and Computer Engineering
Master of Science
Artificial Dielectrics have been characterized using transmission line and s- parameter measurements. The complex dielectric constant and loss of graphite filled and non-poled piezoelectric-aggregate (Polyvinylidene Fluoride, PVDF) filled plastic (PMMA) has been characterized at low (1kHz-10kHz range, i.e., the VLF, very low frequency, range) and microwave frequencies. The average diameter diameter of graphite particles used was thirty microns. Measurements were performed on very fine graphite (one micron diameter grains) and 30 micron sized grains for comparison purposes. Fine grain graphite particles exhibited a, larger real dielectric constant, probably owing to a larger dipole effect. The dielectric constant characterization has also been done for PVDF-graphite-PMMA aggregates. Dissipation factors have been calculated in all cases.
The very low frequency measurements have been done using lossy capacitance principles. The very low frequency behavior of graphite-PMMA. samples showed an anomaly at percolation point (about 15 % of graphite). PVDF-PMMA samples showed no anomaly within the range of concentration measured, probably owing to the fact that PVDF is a dielectric material. At microwave frequencies, it is found that both real and imaginary parts of the dielectric constant experience an increase with the increase in graphite/PVDF loading.
njit-etd1994-030 (107 pages ~ 3,077 KB pdf)
Please complete this Feedback Form to inform us about your experience using this website. It will assist us in better serving your information needs in the future. Thank You!
If you have any questions please contact the Digital Projects Librarian
Created July 21, 2009