Synthesis and Microwave Dielectric Properties of Re ₃ Ga ₅ O ₁₂ (Re: Nd, Sm, Eu, Dy, Yb, and Y) Ceramics

Abstract

Re 3 Ga 5 O 12 (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 Re 3 Ga 5 O 12 ceramics sintered at 1350°–1500°C had a high‐quality factor ( Q × f ) ranging from 40 000 to 192 173 GHz and a low‐dielectric constant (ɛ r ) of between 11.5 and 12.5. They also exhibited a relatively stable temperature coefficient of resonant frequency (τ f ) in the range of −33.7 to −12.4 ppm/°C. In particular, the Sm 3 Ga 5 O 12 ceramics sintered at 1450°C exhibited good microwave dielectric properties of ɛ r =12.4, Q × f =192 173 GHz, and τ f =−19.2 ppm/°C.