Low-temperature Sintering Of (Zn_0.7Mg_0.3)TiO₃Ceramics And The Design Of Filter

In recent years, microwave devices has been widespread concern andcommunication and has gradually developed to miniaturization, which requiresmicrowave devices have to maintain good performance in reducing the volume at thesame time. The LTCC technology has been developed to under the conditions of therapid development and improvement. LTCC Production microwave devices, capacitors,inductors, and other components can be implanted directly into the ceramic modulehaving a three-dimensional structure, which greatly reduces the volume of the device.The same time, it also enabled a high degree of component integration in order to meetthe needs of the miniaturization of electronic devices. To meet the higher requirementsof microwave dielectric low temperature co-fired ceramic material, substrate materialmust have suitable dielectric constant εr, low dielectric loss tanδand near zero τf.ZMT (Zn_0.7Mg_0.3TiO₃) dielectric ceramic material has very excellent microwavedielectric properties: εr=16-22, Q×f=53,000GHz, τf≈55ppm/oC, which has beenextensively studied. Firstly, we have synthesized ZMT ceramic materials by traditionalsolid state reaction method and specific analysis the impact factor of its microwavedielectric properties, such as the calciningtemperature, sintering temperature andtimeand the size of the raw activity. To reduce the sintering temperature of the ceramic,We have added the low melting point of the oxides: Bi₂O₃, V₂O₅, H₃BO₃, Sb₂O₃, PbOas a sintering aid. The experimental results display that ZMT ceramic material withH₃BO₃as sintering aids has obtained the best microwave dielectric properties. AsZMT+1.0wt%H₃BO₃sintered at950°C for3h, the microwave dielectric properties: ρ=4.59g/cm³, εr=20.0, Q×f=4.38×10⁴GHz, τf=-62ppm/oC. In order to adjust thetemperature coefficient of resonant frequency of the ZMT ceramic material τfnear tozero, TiO₂is added to the ZMT-1.0wt%H₃BO₃ceramic materials based on the positiveresonance frequency temperature coefficient τfTiO₂. Through the experimental results,we have displayed that the ZMT-1.0wt%H₃BO₃ceramic materialswith15.0wt%TiO₂have very corresponding microwave dielectric properties: ρ=4.35g/cm3，εr=22, Q×f=2.75×10⁴GHz. Finally, according to the above-described ZMT dielectric ceramics, we havedesignedthe band pass filter of LTCC. It has displayed good frequency selectivity:f0=2GHz, S12≤2dB, S11≥15dB and band rejection>20dB at100M.