The present disclosure aims to improve the performance of a notch filter using a rectangular waveguide and a cavity. A notch filter has a rectangular opening that is formed in an end face thereof. Inside of the notch filter, a waveguide is connected with circular cavities and by connecting pipes. In a planar shape of the waveguide, from an inlet side thereof, a wide path portion, a tapered portion and a narrow path portion are formed and are further connected with a tapered portion and a wide path portion. The circular cavities and designed according to the frequency of the electromagnetic wave that is to be trapped are provided in the middle of the narrow path portion. The configuration of decreasing the width of the waveguide in a location where the circular cavities are provided improves the performance of removal of the electromagnetic wave by the circular cavities.

A millimeter-wave resonator is produced by drilling a plurality of holes into a piece of metal. Each hole forms an evanescent tube having a lowest cutoff frequency. The holes spatially intersect to form a seamless three-dimensional cavity whose fundamental cavity mode has a resonant frequency that is less than the cutoff frequencies of all the evanescent tubes. Below cutoff, the fundamental cavity mode does not couple to the waveguide modes, and therefore has a high internal Q. Millimeter waves can be coupled into any of the tubes to excite an evanescent mode that couples to the fundamental cavity mode. The tubes also provide spatial and optical access for transporting atoms into the cavity, where they can be trapped while spatially overlapping the fundamental cavity mode. The piece of metal may be superconducting, allowing the resonator to be used in a cryogenic environment for quantum computing and information processing.

A waveguide filter includes a fundamental waveguide unit. The fundamental waveguide unit may have an irregular hexagonal metal structure. One wall of the irregular hexagonal metal structure may form a connection to one or more walls of another fundamental waveguide unit having an irregular hexagonal metal structure. A fundamental waveguide unit may include a hollow irregular hexagonal metal structure which includes a resonant cavity that receives an electromagnetic signal and propagates the signal through the resonant cavity.

A multipaction-proof waveguide filter includes a main cavity and a number of corrugations extending from the main cavity. The main cavity includes corrugation interconnect regions between the plurality of corrugations. The corrugation interconnect regions include sloped surfaces, and the corrugations include flared nonparallel sidewalls. Due to the introduced sloped surfaces and flares, an increased Q is achieved, improved roll off is observed and multipaction risks are mitigated.

A multipaction-proof waveguide filter includes a main cavity and a number of corrugations extending from the main cavity. The main cavity includes corrugation interconnect regions between the plurality of corrugations. The corrugation interconnect regions include sloped surfaces, and the corrugations include flared nonparallel sidewalls. Due to the introduced sloped surfaces and flares, an increased Q is achieved, improved roll off is observed and multipaction risks are mitigated.

The present disclosure relates to a filter for filtering wavelengths of an electromagnetic signal to provide a filtered signal. The filter includes: at least one commensurate-line structure (CLS); and, at least one stub-modified commensurate-line structure (SMCLS) arranged to provide a corresponding at least one transmission zero in the filtered signal.

A multipaction-proof waveguide filter includes a main cavity and a number of corrugations extending from the main cavity. The main cavity includes corrugation interconnect regions between the plurality of corrugations. The corrugation interconnect regions include sloped surfaces, and the corrugations include flared nonparallel sidewalk. Due to the introduced sloped surfaces and flares, an increased Q is achieved, improved roll off is observed and multipaction risks are mitigated.

A multipaction-proof waveguide filter includes a main cavity and a number of corrugations extending from the main cavity. The main cavity includes corrugation interconnect regions between the plurality of corrugations. The corrugation interconnect regions include sloped surfaces, and the corrugations include flared nonparallel sidewalk. Due to the introduced sloped surfaces and flares, an increased Q is achieved, improved roll off is observed and multipaction risks are mitigated.

A group delay compensation filter includes: a waveguide that has a first slot and that is configured to transmit a signal; and a first dielectric resonator that includes: a first dielectric, a first metal layer formed over a surface of the first dielectric, and a first opening provided in the first metal layer, wherein the first dielectric resonator is in contact with the waveguide with the first opening coupled to the first slot, and wherein the first dielectric resonator is configured to compensate group delay in a first frequency band of the signal.

A group delay compensation filter includes: a waveguide that has a first slot and that is configured to transmit a signal; and a first dielectric resonator that includes: a first dielectric, a first metal layer formed over a surface of the first dielectric, and a first opening provided in the first metal layer, wherein the first dielectric resonator is in contact with the waveguide with the first opening coupled to the first slot, and wherein the first dielectric resonator is configured to compensate group delay in a first frequency band of the signal.