COMPUTER-AIDED-DESIGN OF INDUCTIVELY-COUPLED RECTANGULAR WAVE-GUIDE FILTERS INCLUDING TUNING ELEMENTS

In this paper we first describe a CAD tool for rectangular waveguide f ilters with tuning elements based on a multimode network representatio n. The equivalence between tuning elements of circular and square cros s section is then investigated. Next we discuss the CAD of a tunable f ilter to be used over a given frequency range. Finally, measured perfo rmances are presented for two types of implementation. The first is a filter structure in which the required frequency of operation is easil y changed by replacing its top cover, without affecting the filter ban dwidth. The second is a traditional implementation using manually adju sted tuning screws. Measured and simulated results are shown to be in good agreement, thereby fully confirming the validity of the CAD tool described. (C) 1998 John Wiley & Sons, Inc.