High performance microwave passive components, as waveguide filter is, require more and more a reduction of the manufacturing costs. A way to reduce the cost of them is to realize substrate integrated waveguide components, where the waveguide structure is embedded in the same substrate which is used to implement the active part of a microwave system. A four pole Tchebyshev X band dual inductive post substrate integrated waveguide filter is designed. The filter has a 5.7% of band at the center frequency of 10.4 GHz (from 10.05 GHz to 10.65 GHz), and is designed to perform at least -20dB of attenuation at 10.4 GHz.
Substrate integrated waveguide (SIW) is a new form of transmission line that has been popularized in the past few years by some researchers. In SIW technology, a rectangular guide is created within a substrate (usually a soft board) by adding a top metal over the ground plane and caging the structure with rows of plated vias on either side. To an EM wave, if everything works out, it looks like a dielectrically-filled rectangular waveguide, with reduced height compared to the “normal” 2:1 width: height ratio. Reduced height is no big deal, it just reduces the impedance the wave sees (increases capacitance/length).
Taha Shahvirdi, and Ali Banai, “Applying Contour Integral Method for Analysis of Substrate Integrated Waveguide Filters,” Microwave Symposium (MMS), 2010 Mediterranean .,pp 418 – 421 , 25-27 Aug. 2010.