Development of image composite ceramics for high-power millimeter-wave applications Original Research Article

image composite dielectric ceramics have been prepared by different sintering techniques including high-temperature, high-pressure sintering (2.5 GPa, T = 1000 °C) and conventional pressureless sintering (T = 1350 °C). Formation of the image secondary phase has been completely suppressed by optimization of the sintering and annealing temperatures. Dielectric properties were measured in the 10–11 GHz range using the cylindrical resonant cavity technique and in the 40–92 GHz range using the open resonator whispering gallery mode technique. At 10 GHz, the optimized composite material image exhibited image and image at room temperature. As an evidence of an additional, low-frequency (possibly Debye-type), extrinsic contribution to the dielectric loss, the Q × f value gradually increased with frequency and reached a plateau of Q × f image at approximately 80 GHz. It is demonstrated that image composites have considerable potential as dielectric resonators in the output multiplexers of communication satellites.