Sintering Condition of Cordierite for Microwave/Millimeterwave Dielectrics

With advent of ubiquitous age, the high quality dielectric materials have been required for the wireless communications available to the millimeterwave as well as microwave frequencies. These high frequencies would be expected for ultra high speed LAN, ETS and car anti-collision system on the intelligent transport system (ITS) and so on. Silicates are good candidate for microwave/millimeterwave dielectrics, because of their low dielectric constant. Cordierite (Mg₂Al₄Si₅O₁₈) is one of the silicates with low dielectric constant (epsiv_r), which are expected for good candidate of millimeterwave dielectrics. This study has been focused on the sintering condition of cordierite: the lowest calcined temperature of 1355degC among 1355 to 1375degC brings a single phase, the highest sintering temperature of 1440degC among 1375 to 1440degC brings a single phase. At 1440degC, the highest density of 2.48 g/cm³ was obtained. Dielectric constant was depended on the sintering temperatures, and the density was also was improved by the cooling rate from sintering temperature. The microwave dielectric properties are as follows: epsiv_r = 6.14, Qldrf= 59682 GHz and tau_r = -26.1 ppm/degC.