**Abstract**

The SIW technology combines complete shielding and fairly low losses with simple and cost-effective manufacturing, thus representing the ideal platform for the development of the next generation of wireless systems, including the band-pass filters among them. In this chapter, a number of novel SIW filter configurations will be presented to improve the filter performance, reduce losses, and minimize the filter footprint. To this end, different topologies of band-pass filters in SIW technology will be described based on stepped-impedance configurations (with high and low dielectric constant sections) making use of the impedance inverter model, extending this concept to half-mode SIW structures, with the aim to reduce the size of the filters.

**Keywords:** filters, substrate-integrated waveguide (SIW), effective permittivity
