Microwave dielectric behaviors at microwave frequency were measured with the TE01δ shielded cavity method with network analyzer (8720ES, Agilent, Palo Alto, CA) and a temperature chamber (Delta 9023, Delta Design, Poway, CA) in the temperature range of 25–85 °C. The Temperature Coefficient of resonant frequency τf value(ppm/°C) is calculated using the following formula: