High efficiency stepped impedance filter

摘要

An RF filter that includes a substrate having a plurality of regions, each having respective substrate properties including a relative permeability and a relative permittivity. At least one filter section is coupled to one of the regions of the substrate which has different substrate properties in comparison to other regions. Other filter sections can be coupled to other substrate regions having different substrate properties. The permeability and/or permittivity can be controlled by the addition of meta-materials to the substrate and/or by the creation of voids in the substrate. The RF filter can be a stepped impedance filter. One filter section includes a transmission line section having an impedance influenced by the region of the substrate on which the filter section is disposed. The transmission line section construction can be a microstrip, buried microstrip, or stripline. A supplemental layer of the substrate can be disposed beneath the filter section.