Recent advances in miniaturization of Substrate integrated waveguide bandpass filters and its applications in tunable filters

The concept of Substrate integrated waveguide (SIW) has emerged to be a good replacement of rectangular waveguides in low-cost and high-volume microwave and millimeter wave band applications. A number of bandpass filters have been developed since the advent of the SIW technology. However, its various forms have also been introduced in order to bring about further reduction in the footprint of these filters. This paper presents a review on the technological implementation of Substrate integrated waveguide bandpass filters and its variant miniaturization techniques developed so far. It also covers the SIW technology applied in tunable filters.