Dielectric properties of magnesium oxide at microwave frequency

To understand the role of a residual MgO phase plays inside a ceramic body, a simple magnesium oxide ceramics was prepared to investigate its microwave dielectric properties. The epsilon(r) and tau(f) values of specimens using simple MgO only vary in a small range at the investigated temperatures (1400-1550 degrees C) implying they are not sensitive to the sintering temperature. However, the Q x f is strongly related to the density of the ceramics and a high Q x f of similar to 113,600 GHz can be achieved by sintering the specimen at 1490 degrees C for 4 h. It indicates MgO may exist as a low-loss dielectric inside a dense ceramic body at microwave frequency. (C) 2010 Published by Elsevier B.V.