Crystal structure and microwave dielectric properties of ATiO3, ATa2O6, AWO4 (A = Ni, Mg, Co) ceramics

Microwave dielectric properties of ATiO
₃
, ATa
₂
O
₆
and AWO
₄
(A = Ni, Mg, Co) ceramics were investigated based on the structural characteristics of oxygen octahedra. ATiO
₃
(trigonal ilmenite), ATa
₂
O
₆
(tetragonal tri-rutile) and AWO
₄
(monoclinic wolframite) ceramics have A- and B-site oxygen octahedra with the different sharing type. Quality factor (Qf) of the specimens was affected by the sharing types of oxygen octahedra. The temperature coefficient of resonant frequency (TCF) of the specimens was decreased with increasing of octahedral distortion per molar volume. The dielectric constant (K) of the specimens was dependent on the dielectric polarizabilities and cations bond valence between octahedral cations and oxygen ion.