Dielectric Properties of Rare-Earth-Added Cordierite at Microwave and Millimeter Wave Frequencies

Abstract

Dense cordierite ceramics were obtained by adding rare-earth oxides at sintering temperatures between of 1355–1420°C. The room-temperature dielectric constants of the cordierite at microwave and millimeter-wave frequencies were evaluated by using the dielectric resonator method. The dielectric permittivity (ε _r) and dissipation factor (tan δ) were determined to be 4.9 and 1.6×10^-4 at 18 GHz, 4.9 and 2.6×10^-4 at 59 GHz, respectively. An 80-mm-long waveguide fabricated with cordierite thus obtained, showed a low transmission loss (<1 dB) at frequency range of 55 to 65 GHz.