The microwave dielectric properties of ceramics based on Ba[(Mg1/3Ta2/3)1−xTix]O3 (BMT-BT) and Ba[(Mg1−xZnx)1/3Ta2/3]O3 (BMT-BZT) were investigated as a function of composition x. In BMT-BT solid solution, the dielectric properties deteriorated with increasing concentration of Ti substitution at the B-site of BMT. A correlation was established between the quality factors of the solid solution phases and their tolerance factor. In BMT-BZT solid solution, where both the end compounds are ordered perovskites, the unit cell expands with increasing mole fraction of the Zn in Mg site of BMT while the dielectric constant increases monotonously from 24.8 (for BMT) to 29.7 (BZT). In BMT-BZT solid solution, the quality factor reaches a maximum (Qu·f = 109,900 GHz) for 60 mol/ of BZT.
