Research And Design Of Ultra-Wideband Bandpass Filter With Multi-Coupling Layout Using Low Temperature Co-fired Ceramic Technology

In order to pursue the mobile digital life, communication equipments are designed to bemore compact and portable. The wireless module, which is used for receiving and transmittingsiginal in these equipments, must be smaller and lighter. On the other hand, in order to transmitmuch more information in a short time, the filter in the wireless module should have wider band.Nowadays, filters with smaller size and wider band become more and more popular. In order toachieve these goals, new manufactural technique and design patterns are needed.In this paper, a filter with the advantages of compact size and wide band is designed. Torealize this achievement, the fundamental of filter should be studied, the elements to form a filterand the relationship between these elements should also be known. With these ideas in mind, thenormal procedure of forming a filter should be known as well as possible. Moreover, in thedesign of this filter, new technology and design process are used. Serval work has been done inthis paper, listed as follow:1．From the aspect of manufacture, new technology called LTCC(Low Tempature Co-firedCeramic) is introduced. It has the advantage to make the filter has a smaller size. Also, LTCCtechnology provides the stability to the filters.2．On the other hand, mult-layer coupling is introduced, which not only decrease the size ofthe filter, but also enforce the coupling between the elements that form the filter, with greatcoupling comes great characterics. Also, with the help of SIR, the filter has a great stopbandcharacteristic.3．Serval kinds of filters are used as examples to show the basic idea of designing a filter.These filters are the contrasts to the filter witch will be given at the end of this paper, they havethe use to show how good the filter designed in this paper.4．At last, with the help of LTCC technology, a wideband filter is designed, it has a center frequency of5425MHz, a passband more than1GHz, and an insertion loss less than1.6dB, it hasa small size of2mm×2.5mm×0.6mm. Moreover, the relationship between the characteristic andthe electrical field of the filter has been studied to provide a referance for future use.