Curved filters in rectangular waveguide

Curved filters are realized by inserting suitably selected discontinuities inside a bend section, instead of a straight section. This configuration replaces the classical cascade filter-bend, saving size, weight and cost, while also increasing the design flexibility of complex microwave networks. Curved cavities are modelled by the local modes approach, whilst discontinuities are represented by a variational multi-accessible mode equivalent circuit. The design starts from the same prototypes used for traditional filters, then compensating the deviations caused by the curvature of the cavities by means of a full-wave optimization procedure.