EDA Design Of Interdigital Bandpass Filter

In recent years, with the rapid development of wireless communication, the microwavefilters are increasingly applied in the fields of radar, spaceflight, and communication etc. Atthe front of the receiver, as one of the most important forms of filtering, the microwavebandpass filter directly influences the performance of the whole receiver. And the interdigitalbandpass filter has made considerable progress in developing because of its lowmanufacturing tolerances, flexible forms and wide stop-band, which has become focus ofcorresponding field. Meanwhile, with the improvement of computer, the accuracy andefficiency of high-frequency electromagnetic EDA simulation software continuously improve,implementing an integration of traditional design method and computer simulation andoptimization, which can improve the design accuracy and shorten the development cycle ofmicrowave filters.At first, this paper briefly introduces the concept of microwave filters, technicalparameters and development trend, and discusses the design process of the interdigitalbandpass filter in particular. Secondly, for the study of interdigital filter of cavity structure, itintroduces the design method of short-circuit type of the terminal line interdigital bandpassfilter, and work out the initial dimension values of the microwave bandpass filter. Then, usingthe full wave electromagnetic EDA software HFSS and CST, model the interdigital bandpassfilter with the initial dimension values, simulate and optimize it so as to meet the requirementsand gain the final dimension values. Finally, draw the mechanical manuscript using thesoftware Auto CAD, and then gain the microwave bandpass filter. We use the vector networkanalyzer to test the performance of the filter. From comparing the simulated graphs with theexperimental ones, we can easily find they agree well with each other, which strongly provesthe validity of the EDA software, as well as the design theory of interdigital bandpass filter.Next, another two interdigital bandpass filter of stripline and suspended substrate striplinestructure are proposed using fast simulation software Ansoft Designer. After mechanizing andtesting them, and comparing simulated results with the experimental ones, again give a strongproof of the feasibility of the EDA software.In a word, the microwave EDA software plays a more and more important role in thedesign of the microwave filters, with the facts that it can improve the design accuracy, shorten the development cycle, and reduce the cost of research.