Efficient computer design of compact planar band-pass filters using electrically short multiple coupled lines

The design of high performance, compact, planar band-pass filters using large numbers of coupled, electrically short, microstrip transmission lines, with multiple non-nearest neighbor coupling, is presented. High order frequency dependent lumped elements are used to accurately represent the filter structure, including all intended or parasitic non-nearest neighbor coupling. While generally applicable, this technique is particularly useful for filters manufactured using thin film High Temperature Superconductors (HTS), where small size is required.