Com Dev Limited

Com Dev International, Inc.

Ming Yu

William A Fitzpatrick

David John Smith

Mihai Vladimirescu

Ying Wang

Qiang Shi

Antonio Panariello

Raafat R Mansour

Wai-Cheung Tang

Apu Sivadas

Bahram Yassini

Van Dokas

R Glenn Thomson

Li Zhu

Zhifu Zhou

S Vahid Miraftab

David Smith

Wiliam A Fitzpatrick

A multi-resonator filter has a signal input terminal, a signal output terminal, and a plurality of resonator components. The plurality of resonator components include an input resonator component coupled to the signal input terminal, an output resonator component coupled to the signal output terminal, and at least one intermediate resonator component coupled between the input resonator component and the output resonator component. The input resonator component, output resonator component and the at least one intermediate resonator component are arranged in a sequence to define a signal path between the signal input terminal and the signal output terminal. The at least one intermediate resonator component includes at least one multiple resonator component, where each multiple resonator component includes a pair of individual resonators coupled in parallel where each individual resonator in a given pair of individual resonators has the same resonant frequency.

Multi-resonator filters

A triple-band bandpass filter with at least one cavity resonator. Each cavity resonator has the same three orthogonal resonances modes corresponding to three unique resonance frequencies. The three unique resonance frequencies define the passbands of the filter. The filter has an input probe coupled to an input cavity resonator. The filter has an output probe coupled to an output cavity resonator. The input and output probes are shaped to concurrently couple signal waveforms in each of the resonance modes. Coupling probes that can be used as input or output probes are also provided. An inter-cavity coupling operable to concurrently transmit signal waveforms in each of the resonance modes is also provided. The inter-cavity coupling can be used to transmit signals between adjacent cavity resonators in the filter.

Multi-band bandpass filter

A microwave filter has a housing defining an inner cavity. A first resonator is positioned in a first portion of the inner cavity. A second resonator is positioned in a second portion of the inner cavity. A third resonator is positioned in a third portion of the inner cavity. The first resonator and the third resonator are cross-coupled via an iris. The second resonator is elongated and is coupled to the first resonator and the third resonator. The resulting microwave filter has a frequency response having a transmission zero in the lower stopband. A high-pass filter is realized without the use of a cross-coupling probe.

Coaxial filter having first to fifth resonators, where the fourth resonator is an elongated resonator

Coaxial filter with elongated resonator

A TE011 cavity filter assembly is disclosed. The system includes at least one resonator operating in TE011 mode having a resonant frequency. The at least one resonator may include a cavity comprising an inner diameter and a cavity length. The at least one resonator may also include a first metal disc inside the cavity. The first metal disc may include a disc diameter and a void in the metal disc, which includes a void diameter and a void depth. The inner diameter of the cavity may be greater than the disc diameter creating a gap with a gap width and a gap depth. The TE011 cavity filter assembly may further include positive coupling.

TE011 cavity filter assembly

A microwave cavity filter is configured for operation in the dual TEmode to realize a very high Q factor at very high frequency ranges. The microwave filter is formed from using one or more cylindrical cavities in which two orthogonal field polarizations of the TEmode are excited and coupled together by means of a coupling element. Different combinations of inter-cavity irises provide for both direct and cross-coupling of aligned field polarizations in adjacent cavities, as required, to realize complex filter functions. The irises may be formed in either a side or end wall of the cavities for both collinear and planar mount configuration. Negative mode coupling also allows for transmission zeros to be realized on either side of the filter passband.

Dual mode cavity filter assembly operating in a TE22N mode

A resonator cavity for supporting a plurality of resonant modes and filtering electromagnetic energy includes a cavity and a resonator element with a mounting flange. The cavity is defined by a top end wall, a bottom end wall and a sidewall and has a longitudinal axis along its length is defined. The resonator element is positioned within the cavity along the longitudinal axis and includes a mounting flange. The resonator element is only in physical contact with the cavity through the mounting flange at a mounting location and where at least one resonant mode of the electromagnetic energy exhibits a local minimum. The dimensions of the cavity and the resonator element are selected so that the associated electromagnetic energy is defined by an electromagnetic field pattern that substantially repeats itself at least twice along the length of the resonator.

Dielectric resonator having a mounting flange attached at the bottom end of the resonator for thermal dissipation

An inline microwave bandpass filter where cross coupling between non-adjacent resonators is realized by changing the orientation of selected resonators. The microwave bandpass filter includes a cavity and three or more resonators arranged in a row (or inline) in the cavity. At least one resonator has a different spatial orientation from at least one other resonator. For example, one or more of the resonators may be rotated 90 or 180 degrees with respect to one of the other resonators. This arrangement of resonators facilitates sequential coupling between pairs of adjacent resonators and cross coupling between at least one pair of non-adjacent resonators without the use of additional cross coupling structures such as dedicated coupling probes or extra cavities. One or more plates may be introduced between adjacent resonators to independently control the sequential and cross coupling.

Inline cross-coupled coaxial cavity filter

A resonator cavity for supporting a plurality of resonant modes and filtering electromagnetic energy includes a cavity and a resonator element with a mounting flange. The cavity is defined by a top end wall, a bottom end wall and a sidewall and has a longitudinal axis along its length is defined. The resonator element is positioned within the cavity along the longitudinal axis and includes a mounting flange. The resonator element is only in physical contact with the cavity through the mounting flange at a mounting location and where at least one resonant mode of the electromagnetic energy exhibits a local minima. The dimensions of the cavity and the resonator element are selected so that the associated electromagnetic energy is defined by an electromagnetic field pattern that substantially repeats itself at least twice along the length of the resonator.

Dielectric resonator and filter with low permittivity material

A cavity microwave filter assembly for filtering an electromagnetic wave including a plurality of cavity resonator assemblies, where each cavity resonator assembly has a bottom and including at least one lossy element for electromagnetically coupling two elements of the filter assembly, where at least one element is a cavity resonator assembly. The lossy elements provide attenuation in the loss variation of the filter and sharper slopes resulting in an improved Q factor for the filter. A method for realizing lossy elements as resistors requires determining an equivalent circuit model that can be manufactured using resistors, coupling elements, and transmission lines. The method includes representing the resistive element with a resistor, unity admittance inverters and coupling elements and then scaling to determine the resistor and coupling values. The method further includes replacing the admittance inverters with transmission lines of the appropriate length to account for the specific design of the filter.

Cavity microwave filter assembly with lossy networks

A method for configuring a microwave multiplexing network having a first channel filter and a second channel filter and an interconnect in order to improve channel performance. The top ends of the first and second channel filters are coupled to the closer of the top and bottom surfaces of the interconnect according to interconnect spacing values and filter to interconnect values. Interconnect values and filter to interconnect values are determined by selecting interconnect spacing values and filter to interconnect values to ensure that a pole is formed causing an additional real reflection zero to be brought into the passband of the microwave multiplexing network thereby increasing the filter order by one. Then interconnect spacing values and filter to interconnect values as well as the internal filter dimensions are selected to ensure that the return loss of the microwave multiplexing network is less than a predetermined return loss level.

Enhanced microwave multiplexing network

A half wave dielectric resonator assembly including a resonator cavity having a top surface and a bottom surface, an elongated cylindrical dielectric resonator positioned within said resonator cavity and first and second insulative supports to couple and insulate the ends of the cylindrical dielectric resonator from the resonator cavity. The dielectric resonator has a substantially small diameter to length ratio. The resonator assembly provides improved spurious performance and quality factor (Q) at a lower mass. A resonator filter is constructed using a plurality of these resonator assemblies, where adjacent pairs of said resonator cavities are separated from each other by a common cavity wall. By forming a first iris opening formed within a first common cavity wall and forming a second iris opening formed within a second common cavity wall having a position that is vertically offset from the position of the first iris, it is possible to reduce stray coupling.

Microwave resonator and filter assembly

A waveguide assembly for operation over a range of temperatures includes a waveguide body and a plurality of restraining strips coupled to the waveguide body. The waveguide body includes a pre-curved narrow sidewall of material having a first coefficient of thermal expansion (CTE). The restraining strips are coupled to the waveguide body at first and second lateral points on either side of the pre-curved narrow sidewall laterally and are spaced apart along the length of the waveguide body, and are made from a material having a second CTE much less than the first CTE. Thus, when the temperature of the waveguide assembly changes, the restraining strips maintain a substantially constant lateral distance between said first and second lateral points over the range of temperatures such that as the length of the waveguide varies with temperature, the curvature of the pre-curved narrow sidewall also changes, causing the effective large dimension of the waveguide assembly to vary such that the combination of said changes results in a constant phase length for said waveguide body.

Phase stable waveguide assembly

The invention provides a method and apparatus for a adaptively predistorted filter which has a transfer function that satisfies performance criteria specified for at (east one property of the filter. The transfer function is obtained by adaptively predistorting the transfer function poles to meet the performance criteria such that at least one of the poles is shifted by a unique amount.

Microwave filter with adaptive predistortion

An externally temperature-compensated microwave resonator comprises a microwave resonator and an external temperature compensator. The microwave resonator is a multi-cavity waveguide. The cavities are configured side-by-side and coupled through irises. The external temperature compensator is oriented and configured to effect a change in volume of the cavities when the resonator and compensator undergo a temperature gradient. The compensator deflects a wall portion of the resonator to accordingly counteract a change in volume of the cavity caused by a temperature gradient.

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Waterloo, Canada

Ming Yu