Research Progress of Phosphate Microwave Dielectric Ceramics with Low Dielectric Constant

Abstract: As the electronic communication industry rapidly advances, microwave dielectric ceramics become a hot topic in recent years. In general, the phosphate microwave dielectric ceramics have many advantages, such as low sintering temperature, low dielectric constant, easily prepared powder material, and no significant chemical reaction with sliver, so they could be taken as the low-temperature co-fired ceramics. In this paper, the author outlined the performance of microwave dielectric ceramics under the common structure models of the orthophosphate (PO₄) and pyrophosphate (P₂O₇) series, and doping and recombination of PO₄ ceramics. The prepared sample is the mixture of PO₄ and P₂O₇ when the ratio of A-element and P-element molar ratio is greater than 1 in research. For the doping of PO₄ ceramics, the A/B ions may be selected for replacement to improve the dielectric property. For the recombination of PO₄ ceramics, the principle of performance improvement is as follows: if the temperature coefficient of original sample is the negative value, the composite TiO₂ makes the temperature coefficient close to 0; if the value is positive, the materials with negative temperature coefficients are compounded to neutralize the temperature coefficient. Finally, the author proposed the problems existed in the phosphate microwave dielectric ceramics and looked forward to the prospect.

Key words: microwave dielectric ceramics, low dielectric constant, low-temperature co-firing, orthophosphate, pyrophosphate, doping and recombination of PO₄ ceramics