Negative permittivity behavior of titanium nitride/polyphenylene sulfide 'metacomposites' under radio frequency

摘要

Random composites with negative permittivity or negative permeability have developed rapidly while few were accomplished using ceramic materials as the functional fillers. In this work, titanium nitride/polyphenylene sulfide (TiN/PPS) composites with different TiN content were prepared by hot-pressing method. The electrical percolation threshold phenomenon occurred and the conductive mechanism transferred from hopping conduction to metal-like conduction when TiN’s content increased. Negative permittivity in composite with high TiN content was derived from low frequency plasmonic state of free electrons and the plasm-like negative permittivity spectra was analyzed by Drude model. Besides, it’s indicated that the dielectric loss was dominated by conduction loss and polarization loss in composites with high TiN content. Equivalent circuit model was utilized to investigate the impedance properties and suggested that parallel inductances played critical role in achieving negative permittivity.