Abstract: Various embodiments for a coaxial low-pass filter are described herein. Generally, the coaxial low-pass filter is operable to generate a stopband by a controlled generation of transmission zeroes within a stopband frequency range. The coaxial filter includes a plurality of cavity junctions, each of the plurality of cavity junctions operable to generate at least one corresponding cavity-specific transmission zero through a dual-mode coupling of a transverse electromagnetic and a transverse magnetic resonant mode, the at least one cavity-specific transmission zero being generated at at least one corresponding frequency located within the stopband frequency range, wherein for each cavity junction, the location of the cavity-specific frequency is adjusted by adjusting at least one property of the cavity junction, wherein a scattering of the locations of each of the cavity-specific transmission zeroes, generated by each of the plurality of cavity junctions, generates the stopband at the desired frequency range.

Abstract: A bandpass filter has a plurality of resonant cavities. The plurality of resonant cavities are arranged into a sequence of adjacent resonant cavities. Each resonant cavity is configured to define the same fundamental resonant frequency. The filter includes a plurality of coupling irises, with one of the coupling irises positioned between each pair of adjacent resonant cavities. Each resonant cavity includes a plurality of cavity sections. Each resonant cavity includes a capacitive iris positioned coupling the cavity sections to one another. The frequency of secondary resonance modes varies amongst the resonant cavities in the plurality of resonant cavities.

Abstract: A bandpass filter has a plurality of resonant cavities. The plurality of resonant cavities are arranged into a sequence of adjacent resonant cavities. Each resonant cavity is configured to define the same fundamental resonant frequency. The filter includes a plurality of coupling irises, with one of the coupling irises positioned between each pair of adjacent resonant cavities. Each resonant cavity includes a plurality of cavity sections. Each resonant cavity includes a capacitive iris positioned coupling the cavity sections to one another. The frequency of secondary resonance modes varies amongst the resonant cavities in the plurality of resonant cavities.

Abstract: An embodiment of the present invention provides a voltage-controlled tunable filter, comprising a tunable ridged waveguide filter formed from a first ridged waveguide cavity coupled to a second ridged waveguide cavity thereby forming a resonator; and one or more tunable capacitors in at least one of said first or second waveguide cavity. The coupling between said first ridged waveguide and said second ridged waveguide may be via a coupling iris or ridged post and the one or more tunable capacitors may comprise a low loss tunable dielectric material and metallic electrodes with predetermined shape, size, and distance. In an embodiment of the present invention the one or more tunable capacitors may be MEMS tunable capacitors that are either parallel plate or interdigital topology.

Abstract: A waveguide filter is provided having a plurality of asymmetrical corrugated resonators. The filter may also include an input section and an output section including a low-pass filter unit and a transformer unit. The low-pass filter unit includes a plurality of symmetrically corrugated slots, and the transformer unit includes at least one stepped transformer section for matching the filter to an external waveguide line. Each of the asymmetrically corrugated resonators may include a pair of opposed slots of different depth, a long slot and a short slot. The resonators provide at least one reflection zero and two transmission zeros to the frequency response of the filter, thus providing high-pass, band-pass and low-pass filter properties in a single filter structure.

Abstract: A corrugated waveguide filter has a plurality of coupled resonator cavities arranged in a horizontal or vertical manner. The filter may include an input transformer section and an output transformer section for matching the filter to external waveguide lines. Each resonator includes at least two extracted slots (or cavities) that are grouped in close proximity to each other, and which may be symmetrically or asymmetrically implemented in the waveguide. The resonators each contribute one reflection zero and two transmission zeros to the frequency response of the filter, the reflection zero being located within the pass-band of the filter, and the two transmission zeros located either at the high-side or low-side of the pass-band depending upon whether the resonator is a low-pass type or a high-pass type. The dimensions of each resonator, including the depth of the slots and the distance between the slots, determines the position of the reflection zero and whether the resonator is low-pass or high-pass.