Microwave resonator filters for advanced wireless systems.

The motivation behind this work is to reduce the size and mass of modern and next-generation wireless systems by developing novel filter architectures as well as design methodology for the advanced microwave filters. The proposed microwave filters can make a significant impact on wireless systems by replacing bulky microwave filters. This is accomplished as the size and mass of the entire wireless systems are mainly determined by those filters. Wireless systems, such as mobile and satellite communications systems and radars, rely on wider frequency channels than before, which in turn require more microwave filters for each wireless unit. With the conventional design approach, the number of microwave filters equals that of allocated frequency channels, which results in a substantial increase in size and mass of the wireless systems. In response to these demands, this thesis will demonstrate new filter architectures and analytic design methods to be applied to such filters. Firstly, a synthesis method for dual- and triple-passband microwave resonator filters is described. This method employs frequency transformation techniques for analytic design of the filters. This can be used to design multiple-passband filters with prescribed passbands and attenuation at stopbands. Secondly, this work provides an analytics design procedure for tunable microwave filters. This approach makes it possible to achieve tunable filters showing the same frequency response when the center frequency is adjusted. Finally, this work provides a method to design high-performance miniaturized filters. Since good electric performance is not affordable for small-size filters, this work presents transmission zero technique for improving electrical performance of miniaturized filters. The novel analytic design procedures presented in this thesis will facilitate the design of the microwave filters, which will replace bulky conventional microwave filters. The design approaches will dramatically improve the realization of modern and next-generation wireless communications systems with small size and lighter weight.Ph.D.Applied SciencesElectrical engineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/127120/2/3382262.pd