Synthesis and microwave dielectric properties of Re3Ga5O12 (Re: Nd, Sm, Eu, Dy, Yb, and Y) ceramics

Re3Ga5O12 (Re: Nd, Sm, Eu, Dy, Yb, and Y) garnet ceramics were synthesized and their microwave dielectric properties were investigated for advanced substrate materials in microwave integrated circuits. The Re3Ga5O12 ceramics sintered at 1350 degrees-1500 degrees C had a high-quality factor (Q x f) ranging from 40 000 to 192 173 GHz and a low-dielectric constant (epsilon(r)) of between 11.5 and 12.5. They also exhibited a relatively stable temperature coefficient of resonant frequency (tau(f)) in the range of -33.7 to -12.4 ppm/degrees C. In particular, the Sm3Ga5O12 ceramics sintered at 1450 degrees C exhibited good microwave dielectric properties of epsilon(r)=12.4, Q x f=192 173 GHz, and tau(f)=-19.2 ppm/degrees C.