A method and apparatus to provide appropriate coupling between resonators
in an HTS microstrip filter are disclosed. Primary and secondary
couplings between a pair of resonators are utilized. With a given
spacing, the primary coupling is fixed, while the secondary coupling can
have different magnitude. In addition, the secondary coupling can have
the same phase or opposite phase as the primary coupling. With different
combinations, large or small bandwidth filters can be made without very
small or very large spacing between resonators. The same cross coupling
layout configuration may be designed to achieve either positive or
negative results.