Design of substrate integrated waveguide components using mode-matching techniques

A simple, yet efficient mode-matching technique (MMT) is presented for the analysis and design of substrate integrated waveguide (SIW) circuits. The computational domain is formed by a rectangular box of electric and magnetic walls within which square via holes can be arbitrarily moved during an optimization process. The small substrate height limits the modes to those of the TEm0-mode set. In order to adapt to common fabrication facilities, in which circular via holes rather than square ones are used, a simple conversion formula is introduced. Two examples of quasi-elliptic filters are presented. The excellent agreement of responses from the MMT with square vias and CST with circular vias validates the analysis and design procedure.