Inductive Cascaded Quadruplet With Diagonal Cross-Coupling in Rectangular Waveguide

The objective of this paper is to show how inductive quadruplets with diagonal cross-couplings can be used as building blocks for filters in rectangular waveguide. Starting with the coupling matrix synthesis, we show how very general transfer functions can be easily implemented with a very simple step-by-step procedure. In addition to coupling matrix theory, we also describe distributed networks that can be effectively used to carry out the transition from coupling matrix descriptions to actual waveguide structures. Several filter design examples are also described in detail. Finally, measured results are also discussed showing excellent agreement with simulations, thereby fully validating both the new family of filter structures and the related design procedures.