We measure several electromagnetic properties of tungsten-Teflon composites as a function of metal volume concentration. The electric (E) and magnetic (H) loss tangents at 2.45 GHz and the dc conductivity each exhibits a percolation transition at a different critical value of the metal volume fraction p. Moreover, the transition behavior depends on the average particle size and size distribution of the metal component. We explain the variation in each case by a schematic model derived from established percolation theory and the distinct response of conducting particles to microwave electric and magnetic fields.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)