Design of broadband directly coupled non-centred resonant irises filters

A novel type of broadband highly selective filters in waveguide technology is presented. It is based on directly coupled resonant irises filters. The position of the apertures is studied in order to obtain a filter structure which is easier to construct. The mode matching method is used for the design and simulation of the structure. An efficient optimisation method is employed to overcome the design problems that presents the non-centred irises approach, namely, the higher order modes excited in these discontinuities that strongly modify the couplings between adjacent irises. This optimisation method is based on the estimation of these couplings, so it can be efficiently used to tune the dimensions of the initial design.