ZrTi2O6 filled PTFE composites for microwave substrate applications

A new kind of ZrTi2O6 filled polytetrafluoroethylene (PTFE) microwave composite substrates was fabricated through the hot-pressing process. The microwave dielectric properties of ZrTi2O6/PTFE composites were measured using stripline resonator method. The relative dielectric constant (epsilon(r)) and loss tangent (tan delta) of the composites increase with an increase of the volume fraction of ZrTi2O6 ceramic (0-46 vol%). The experimental dielectric constants of the composites match well with theoretically predicted values by Lichtenecker mixing rule. As the volume fraction of ZrTi2O6 ceramic increases, the thermal expansion coefficient and the temperature coefficient of dielectric constant decrease. The ZrTi2O6 filled PTFE composite exhibits a dielectric constant of 7.42 with a loss tangent of 0.0022 (10 GHz) at an optimum filler loading of 46 vol%.