The Effect of Increased Design Bandwidth Upon Direct-Coupled-Resonator Filters (Correspondence)

The Cohn synthesis is generally preferred as a convenient design technique for direct-coupled waveguide filters covering a moderate bandwidth. Approximations inherent in the theory result in considerable deviations from the theoretical pass band response as the design bandwidth increases. The magnitude of the deviations is difficult to predict and proves troublesome in designs requiring a low pass band VSWR.