Research On Micro Multimode Filter

Society has become a massive vessel which is made of Information Technology in many fields and it helps optimize the living conditions and life-style of human beings. Mobile or Portable Internet has been widely applied within years on almost every professions. Independent Mobile service of information is the mainstream and epidemic direction of service industry, which brings people exhaustive and comprehensive convenience both on work and life. As the bridge of information service, Wireless Communication has been encountering unprecedented opportunities but also arduous challenges because of the large increasingly amount of data.Filter and multiplexer are vital components on signal isolation and acquisition in the wireless system. Considering the limited spectrum resources, the partition of each channel should be more trivial to realize a more high utilization and efficiency of spectrum. In addition, low cost, high integration and miniaturization are the trend of electronics industry. Thus making research and development on miniature、high performance filter seems more urgent.Traditional cavity, Coaxial and micro-strip TRL filter cannot meet all the requirement mentioned above. It is essential to combine classic filter theory and industry crafts to implement modern RF and Microwave filter design. With the industry crafts’development such as LTCC, LCP and HTCC Technology, integrated microwave passive, active circuit and devices greet a fabulous opportunity to move on.Dual-mode and multi-mode resonate structure are adopted widely in microwave engineering filter design due to their brilliant electrical performance such as priori miniature characteristic and controllable resonate frequency of both base mode and high-order mode. The costs and design efficiency are acceptable as the structures mentioned above are simple and easy to fabricated.Miniaturization is the research focus of modern electric device. In microwave filter and other passive device fields, multi-mode resonate、capacitor equivalent and step impedance resonate technology are constantly applied to implement miniaturization.Based on LTCC technology, a large amount advanced articles’RD directions and applied methods about miniature multi-mode filter are analyzed. Four different kind structures in total five miniature filters including narrow-band filter、dual-band filter and multi-order high performance filter were designed with the integration of the resonate characteristics of dual mode、multi-mode and step impedance and LTCC multilayer technology. All the filters mentioned above testify the advantages of LTCC technology and multi-mode resonate characteristics.The filters is easy to design and fabricate with simple structure and excellent performance. Four kinds of filters’ volume is 4.8mmx3.2mm×1.5mm and the volume of the rest one is 9.12mm×4.2mm×1.5mm. With good performance and miniature volume, the filter mentioned above can be applied widely in mobile terminal, base station, satellite communication, military application and other occasion in which highly device performance and volume are required.One of the design filter belongs to a cooperation project with some national defensive research institute. Simulation results satisfy the demands completely. Now the filter in the fabrication process.