FDFD modeling of substrate integrated waveguide without phase-bias

In this paper, a finite difference frequency domain (FDFD) method is used to analyze a new class of substrate integrated waveguides (SIW) that are formed by using periodic metallic slots instead of metallic vias. When the gaps between slots are small enough, the broadside dimension of their equivalent rectangular waveguide is approximately equal to the spacing between inner walls of the slots. This means that the design of substrate integrated waveguide circuits (a family of substrate integrated circuits or SICs) such as resonators and filters based on the SIW concept can greatly be simplified. A new FDFD algorithm is proposed to analyze the substrate integrated waveguide resonators. Combining with a perfectly matched layer (PML) technique, the FDFD algorithm based on Maxwell´s equations is extended and can be used to analyze open resonant problems.