Study And Design Of Microstrip Ultra-wideband And Multi-band Bandpass Filter

Under an increasingly crowded wireless spectrum resources and complexelectromagnetic environment, the performance of the filter is demanded more and more.While ultra-wideband with the broadband high confidentiality and anti-interferenceability and multi-band have great advantages in the utilization ratio of the frequencyspectrum resources and frequency compatibility, so they become a hot research topic inrecent years. This paper is focused on the design of the ultra-wideband bandpass filterand multi-band bandpass filter, adopting multi-mode resonators, odd-even moderesonators, open loop resonators based on microstrip structure, a few ultra-widebandfilters and multi-band bandpass filters are designed.The main content of the concrete work are as follows:First of all, this paper summarizes the current research status of the filter and hotspots, which based on the related literature at home and abroad of collection andanalysis. Then, this paper introduces the related index, synthesis theories and resonatortheory, mainly on the ome resonators, synthesis theories of ultra-wideband filters andmulti-band bandpass filters.Secondly, we focus the ultra-wideband bandpass filter based on Multi-moderesonator (MMR). This paper introduced the frequency characteristics of the resonators,the external and internal coupling structure of the ultra wideband bandpass filter aredesigned, the measured results verified the simulated ones.Finally, the design of multi-band bandpass filters is reseached. Based on odd-evencharacter, a microstrip line dual-band bandpass filter using modified stub-loadedresonators with wide stopband is proposed. A microstrip line dual-band bandpass filterusing folded stepped-impedance resonators (FSIRs) with high selectivity isimplemented. A microstrip quad-band bandpass filter using open-loop resonators andfour orders stepped impedance resonators is designed. These filters are fabricated andmeasured to validate the design approach.