US Patent 7132381 Process of preparing low-temperature sintered microwave dielectric ceramics

There is provided a process of preparing low-temperature sintered microwave dielectric ceramics, prepared by a process comprising co-precipitating Nb and Bi or Zn in an aqueous basic solution to obtain a BiNbO4 or Zn3Nb2O8 precursor powder, thermally decomposing the powder to obtain BiNbO4 or Zn3Nb2O8 powder, adding CuO and V2O5, pulverizing and sintering the mixture, which produces ceramics having small dielectric losses (Q·f0>15,000 GHz) and high dielectric constant (k=20–45) at microwave frequencies by sintering at a low temperature of 700 to 750° C. Thus, the microwave dielectric ceramics prepared in accordance with the present invention can be advantageously used in multi-layer ceramic packaging such as filter planar antenna, microwave oscillator, etc., which comprise base metals such as silver (Ag) and copper (Cu) as an internal electrode.