Explicit design formulae for wideband bandpass filters

A new design technique is developed for the realization of wideband bandpass filters synthesized in the form of a lowpass filter cascaded with a highpass filter. For the maximally flat and chebyshev response cases, approximate explicit design formulae are provided to allow a direct design technique to be used.

Results obtained by using this design technique agree with those obtained by direct synthesis and offer a significant improvement over the direct lowpass—highpass cascade obtained by frequency scaling.