The Study On Microwave Ceramic Filter Design And Preparation Technology

Along with the exploitation and application of the high frequency radio wave as well as the rapid development of the mobile communication, more and more attentions have been paid to the microwave filter. Microwave dielectric ceramic material has the characteristic of low loss, low frequency-temperature coefficient and high dielectric constant. With the constant development of the microwave dielectric ceramic material and the improvement of its capability, the filter made of the microwave dielectric ceramic material has the virtues of reliable capability, low insertion loss, little volume, high stability ,which made the microwave dielectric filter playing an important role in the communication industry.The development situation of the microwave dielectric ceramic material and the device made of it were presented briefly, the development of the microwave dielectric ceramic filter was introduced emphatically. The design principle and the design method of the microwave dielectric ceramic filter were dissertated., and the microwave dielectric ceramic filter was simulated with the HFSS, which has the performance of center frequency=0.89 GHz,insertion loss<2.5 dB,bandwidth=±15 MHz,in-band ripple =0.8 dB,attenuation>0dB. The moulding technics of the device was one of the most important step of manufacturing device, especially with the miniaturization and the complication of the device,. the traditional pressing forming cost high and rigorous manufacture was difficult to achieve, then a different kind of technics must be seeked and applied. In this paper, the microwave ceramic (Ba6-3x(Sm1-yNdy)8+2xTi18O54)was pitched to the preparation of the device. The Gelcasting technics which applied to the PTC moulding technics was applied to the microwave dielectric ceramic. Moulding the microwave device and compared the technics with the traditional pressing forming, the Gelcasting technics can be used to mould the microwave device. Last using the Gelcasting technics to produce the designed filter, and plating silver to the device sample from out-surface to in-surface according to the design request . Finally, the measured outcoming of the filter was compared with the HFSS emulate and the result was analyzed.