Design Of Microwave Non-redundant Band-pass Filter Using Microstrip And Edge Coupled Sections

Abstract

Microwave filler design using the non-redundant method relies on using the quarter wave Unit Elements (U.E's) to create a complex pole and hence augment the filter skirt response as against the redundant method wherein the U.E's do not contribute towards the filtering action. Filters realized using this method may have series high impedance capacitors, which are not realizable in planar microstrip technology. This thesis proposes a method to integrate microstrip transmission line and coupled line elements to circumvent the problem of realizing series capacitance. The total number of transmission line elements required to realize the filter is the minimum number required by the multipole filter. The filter realized in this work is based on the work by Horton and Wenzel on realizing optimum quarter-wave TEM filters. Sonnet software is used to simulate and verify the calculations. The fabricated filter was measured using the network analyzer and the results are included.