Abstract: A dual operation mode all temperature filter is provided. The dual operation mode filter is provided with a housing defining at least two cavities, an input port and an output port. It is also provided with a non-superconducting resonator disposed in a first one of the cavities and a superconducting resonator disposed in a second one of the cavities. The second resonator comprises a superconducting material containing 8-15% silver. The dual operation mode filter filters at a relatively high level at temperatures below a threshold temperature and at a lower, conventional level, at temperatures below the threshold.

Abstract: An electromagnetic filter includes a filter housing containing a first resonant cavity and a second resonant cavity. Resonators are disposed within each of the cavities. The electromagnetic filter also includes a cavity wall separating the first resonant cavity and the second resonant cavity. The cavity wall includes a T-shaped aperture to achieve magnetic coupling between the first resonant cavity and the second resonant cavity.