Array of directional filters

Abstract From the Canadian patent

A transponder includes twelve directional filters that operate in both band stop and band pass modes. The pass and stop bands of each filter has a center frequency that is substantially the same as the center frequency of one of twelve signal channels of the transponder, whereby each channel corresponds to a filter. The twelve filters are connected to a rectangular waveguide at selected relative displacements from a downstream end thereof. Signals within one of two groups of six alternate adjacent channels are propagated through their corresponding filters and through the downstream end without either an undesired signal loss or an undesired group delay. Signals within five channels of the …