Dielectric properties of epoxy resin-barium titanate composites at high frequency

DGEBA type epoxy resin, D.E.R. 33 1, was mixed with barium titanate, Y5V fillers, then cured with diaminodiphenyl methane (DDM). It was. p found that the dielectric constant at high frequency, 1 M-1 GHz, increases with the solid content of barium titanate. By adding 80 wt.% of Y5V fillers, the dielectric constant at I GHz can be increased from 3.2 of the sample without fillers to 13.1. A Lichtenecker's mixing model was proposed to describe the dielectric constant profile dependent on the filler loading. Furthermore, a model chip antenna was prepared and covered by an epoxy-barium titanate composite. The fundamental resonant mode of the antenna is excited at 2.452 GHz with a 10-dB return-loss bandwidth of about 191 MHz. It suggests that the antenna would be applied in 2.4 GHz ISM band for wireless communications. (c) 2006 Elsevier B.V. All rights reserved.