Read the article: Combline cavity filter.
In this tutorial we will learn how to synthesize and implement a chebyshev response with a combline cavity topology using Couplings Designer. Couplings are extracted and linked to physical dimensions and then combined to realize the final filter layout. It will be shown that unintended couplings may distort the passband and stopband performance. These coupling are analyzed by Couplings Designer with a new coupling matrix that takes them into account and the final physical dimensions are tuned to reflect the change, finally retreiving the chebyshev response.