High temperature superconductor lumped element band-reject filters

Abstract

Lumped element electrical components, such as inductors and capacitors, are formed to include high temperature superconducting materials. In the preferred embodiment, thin film epitaxial high temperature superconductors are patterned to form capacitors and inductors on low loss substrates. Preferably, a ground plane is formed on the back side of the substrate, most preferably being formed of high temperature superconducting material, or other highly conductive materials such as gold or copper. Various advantageous structures include a planar spiral structure, a zig-zag serpentine structure, a single coil structure and a double coil structure. Single layer and multilayer structures are included. Improved narrow bandpass filters, bandreject filters and high Q resonator structures are formed. Chebyshev bandpass filters are formed from multiple series connected zig-zag filter structures. Chebyshev, elliptic and quasi-elliptic bandreject filters are formed from a plurality of bandreject structures, each of which includes a zig-zag or serpentine inductor. A quasi-elliptic bandpass filter utilizes a plurality of series connected bandpass structures with planar cross-coupling of bandpass structures.