Study On The Properties Of ZMT Dielectric Ceramics Based On Glass Sintering Aids And Its Application On Filter

With the rapid development of the wireless communication system and microwave products, small, light weight and multifunctional electronic components are attracting much attention. LTCC echnology can meet the requirements of miniaturization, high density, multifunction and high reliability of the electronic device. It is very important to develop a new type of microwave dielectric ceramic material for realizing the miniaturization of microwave devices and ensure its good performance.In this paper, we studied the microwave dielectric properties of ZMT dielectric ceramics at low temperature sintering. We have added low melting point glass BBSZ, BBZ, CBS, LBSCA as the sintering agent to reduce the sintering temperature of the ceramic. We analyzed the density, phase composition, microstructure and microwave dielectric properties of the ceramic to observing the influence of different sintering aids on the properties of the ceramic. Presintering at 850℃ for 2 hours, and sintering 3 hours at 900℃,925℃,950℃ after doped glass. The experimental results show that the best microwave dielectric properties can be obtained when the ZMT ceramic with 1wt% LBSCA: εr=21.6,Q×f =62000GHz,τf =-60ppm/℃. To regulate the TCF value of the ZMT ceramic near to zero, Ti O2 and Ca Ti O3 are added to the ZMT-1wt% LBSCA ceramic based on the positive TCF of Ti O2 and Ca Ti O3. Through the experimental results, Ti O2 added in the adjustment of TCF value will lead to a sharp decline in the Q×f value of ceramic materials. We can obtain he best microwave dielectric properties when the ZMT-1wt% LBSCA ceramic with 10wt% Ti O2: Q×f=12100GHz,εr=20.6,τf=-5.6ppm/℃. When doping Ca Ti O3 to regulate the TCF value, the Q×f value of ZMT ceramic materials will be significantly decreased, and the amplitude is much larger than Ti O2. We can obtain he best microwave dielectric properties when the ZMT-1wt% LBSCA ceramic with 5wt% Ca Ti O3: Q×f=5290GHz,εr=17.2,τf =1.4ppm/℃.Finally, we have designed a band pass filter of LTCC based on the substrate material of ZMT-1wt% LBSCA ceramics sintered at 900. It has displayed good frequency selectivity: f0=2.8GHz, S12 ≤ 2.8d B, S11 ≥ 15 d B and band rejection >20 d B at 100 M. The developed filter can meet the requirements of the project.