Microwave properties of the ceramic compositions M2+Ti4+ 1?x Me4+O3

The systems MgZr _x TiO₃, Mg_1?y Ca _y Ti_1?x Sn _x O₃, where Ti⁴⁺ is partially substituted by Zr⁴⁺ or Sn⁴⁺, and a series of compositions Mg (Ca_1.5Ta_0.2) _x Ti_1?x O₃, where Ti⁴⁺ is partially substituted by the four-valent cation (Ca_1.5Ta _0.2)⁴⁺, have been synthesized. For all compositions it was found that the permittivity ε_r and quality factor Q decreased monotonically with increasing substitution factor x. The measurements were carried out within the frequency range 9–11 GHz. At lower x, the quality factor had high values, so that such compositions could be used as microwave resonators with controllable parameters (for instance, for satellite television). The relationships between Q and x which have been obtained, together with the changes in density, are interpreted.