High dielectric constant and high‐Q in microwave ceramics of SrTiO ₃ co‐doped with aluminum and niobium

Al/Nb co‐doped SrTiO 3 microwave ceramics with the composition of SrTi 1– x (Al 0.5 Nb 0.5 ) x O 3 ( x = 0.03, 0.05, 0.1, and 0.15) have been synthesized via a standard solid‐state reaction method. The substitution of (Al 0.5 Nb 0.5 ) 4+ in B‐site inhibits the reduction in Ti 4+ ions and the growth of grain size, then the transport of mobile charge carriers is limited, and thus the Q value is improved. For the SrTi 0.9 (Al 0.5 Nb 0.5 ) 0.1 O 3 ceramics, in addition to their high dielectric constant (ε r ~185), they exhibit correspondingly a high Qf value (~ 9077 GH z) at 2.9 GH z, making the microwave ceramics suitable for myriad device miniaturization and high‐performance wireless communication.