Scheme for the Implementation of Cross-Couplings for Highly Tuneable Filters

An architecture of a quadruplet for the realization of inductive waveguide filters, in which the by-pass coupling of the two central cavities is inductive, instead of the more classical capacitive solution, is proposed. This arrangement is quite handy because it makes easier the realization of very weak couplings, as those required in such schemes, without the need of expensive solutions. At the same time, one capacitive coupling is used to couple two electrically adjacent cavities of the quadruplet, possibly the more external ones, so that the coupling is large enough to be effectively implemented.