Space Systems/loral, LLC

Stephen C Holme

Slawomir J Fiedziuszko

Stephen D Berry

Lawrence Alan Carastro

Robert N Seehorn

David Max Solomon

Hiroyuki Ikemoto

Norman L O'Neal

S Jerry Fiedziuszko

Yujiro Honmyo

Michael Thorburn

Craig Ziegler

A radio frequency (RF) dielectric resonator filter includes at least a first cavity and a second cavity, each cavity being loaded with a dielectric resonator. The first cavity is separated from the second cavity by a common wall, the common wall including a first and second aperture that couple an electromagnetic field between the first cavity and the second cavity. A first externally adjustable tuning screw extends from the second aperture, a portion of the tuning screw being external to the filter. The first aperture is an iris disposed in a central portion of the wall and the second aperture is disposed proximate to a perimeter of the wall. The second aperture has an effective area that is adjustable by the first externally adjustable tuning screw.

Dielectric resonator filter and multiplexer having a common wall with a centrally located coupling iris and a larger peripheral aperture adjustable by a tuning screw

A multiplexer includes a microstrip manifold, and a filter bank having at least two output filters. The multiplexer channelizes an input radio frequency (RF) band of electromagnetic energy into a set of output channels by way of the filter bank. The microstrip manifold has an input port that receives an input RF signal, and at least two output ports. The microstrip manifold distributes the input RF signal to each output port, each said output port being coupled to a respective one of the at least two output filters. The multiplexer may be an input multiplexer for a spacecraft communications payload system.

Microstrip manifold coupled multiplexer

An RF bandpass filter includes a cascaded series of a first subfilter and a second subfilter. Each subfilter includes a respective inverter, voltage-controlled capacitor and inductor. A first selected one of the first subfilter and the second subfilter is a pseudo low pass filter and a second selected one of the first subfilter and the second subfilter is a pseudo high pass filter. The RF bandpass filter is configured to separately control a bandwidth and center frequency of output RF energy. The bandwidth may be controlled to be substantially fixed over a significant substantial range. The center frequency and bandwidth are controlled by adjusting a voltage input to one or more of the voltage-controlled capacitors.

Frequency and bandwidth tunable microwave filter

A dual mode dielectric resonator (DR) filter has a first DR, and is configured to operate at a HE12&#x3b4; mode within a first frequency band while exhibiting a Q factor of no less than 5000. A first characteristic size of the first DR may be substantially similar to a size of a second DR, where the second DR is configured to operate in a conventional DR filter at a HE11&#x3b4; mode within a second frequency band, the second frequency band being substantially lower than the first frequency band.

Dual mode dielectric resonator operating in a HE mode with a Q factor no less than 5000

A multi-cavity RF filter has at least one electrically conductive coupling probe disposed between two resonator cavities. The coupling probe is provided with an ESD protective arrangement such that the coupling probe is electrically connected to a metallic housing of the RF filter only by the ESD protective arrangement. The ESD protective arrangement is configured to provide (i) a low resistance electrical path from the coupling probe to the metallic housing and (ii) a high impedance to RF energy having wavelengths proximate to a center frequency wavelength of the RF filter.

Electrostatic discharge control for a multi-cavity microwave filter

A communication system having gateway filter and switching networks in forward and return channels of a frequency reuse communication satellite. The system couples subscriber terminals to the Internet or other terrestrial network by way of one or more gateways. The system cross-straps gateway-to-user beam connectivity provided by the communication satellite to allow full coverage of all user beams with a subset of the gateways having reduced frequency reuse. An exemplary system comprises a communication satellite having a return channel and a forward channel. One or more gateways are coupled to the Internet or other terrestrial network and communicate with subscriber terminals by way of the return and forward channels provided by the satellite. The return and forward channels each comprise a filter and switching network that selectively couple signals between the one or more gateways and the subscriber terminals. The filter and switching networks selectively couples signals between selected gateways and selected subscriber terminals using predetermined beams.

Satellite communication system with gateway switch networks

A filter that produces a multiple passband response as a single device. The multiple passband filter has a plurality of poles concentrated in a desired passband of the filter. A plurality of zeroes are located outside of the desired passband to form passband edges. One or more zeroes are located in a central portion of the passband to form multiple passbands within the passband edges.

Multiple passband filter

A series of tuning brackets are mounted on the microwave waveguide manifold at positions between the input waveguide/filter couplings. These brackets constrain the manifold and are constructed with adjustment screws extending through the brackets and mechanically connected to the manifold. The movement of the adjustment screw will tend to deform the manifold dimensions resulting in a fine adjustment of the wavelength (&lgr;) of the multiplexer.

Microwave multiplexer with manifold spacing adjustment

An extended band, multiple channel multiplexer 10 well-suited for use with satellite communications systems. The multiplexer utilizes a low attenuation, contiguous diplexer 18 containing contiguous diplexer filters 18a to combine two sections 11a, 11b of the multiplexer respectively containing contiguous channel filters 14a, 14b. The multiplexer comprises low attenuation, contiguous diplexer filters 18a tuned in tandem with channel filters 14a, 14b to provide contiguous multiplexing. This approach takes advantage of the constructive interaction between these filters to realize an equivalent contiguous multiplexer. This enables realization of a wide band contiguous multiplexer, which heretofore was impossible to tune. The contiguous diplexer eliminates spurious modes of the channel and diplexer filters, spurious waveguide modes, and out of band interaction between the two portions of the multiplexer. Therefore, tuning of the multiplexer is possible.

Wide band contiguous multiplexer having a contiguous diplexer

A dielectric resonator filter has a series of cavities enclosing respective ones of a series of dielectric resonators, wherein each cavity includes a resonator support configured as a cylinder of thermally conductive, electrically insulating material such as boron nitride. The support is positioned coaxially with the resonator along a central axis of the cavity, and is located in tandem with the resonator. Physical connection of the support to the resonator is facilitated by provision of a thread along an inner surface of the support, and the provision of an outer thread on the resonator surface to be received within the thread of the support. The support is mounted to an end wall of the cavity, thereby to complete a thermally conductive path for withdrawal of heat from the resonator to the exterior of the filter. Each support is provided with windows through which tuning and/or mode coupling screws can be inserted, thereby to locate a screw behind an end surface of the resonator. The screw is supported by a sidewall of the cavity and extends radially inward of the cavity in a plane which is parallel to the resonator end surface and spaced apart from the end surface to inhibit the formation of electric discharge arcs in the case of elevated electromagnetic power. Coupling between cavities is accomplished by means of a cruciform iris.

High power dielectric resonator filter

A waveguide cavity filter having a conductive housing, a plurality of high dielectric constant ceramic resonators disposed within the conductive housing and at least a portion of a sheet of superconductive material which is constrained to be at an ambient temperature below the critical temperature of the superconductor and disposed in contact with at least one of the side walls of the conductive housing and with an opposing surface of each of the resonators, such that the resonators are in close superconductive contact with the side walls of the conductive housing. In particularly, the superconductive sheet is a layer of high temperature superconductor. In a first embodiment of the invention, the resonators in the shape of cylindrical plugs are disposed with a flat surface juxtaposed to the side wall. In a second embodiment, the resonators are in the form of half cylindrical plugs with the axis of the half cylinder transverse to the axis of the resonator, in contact with the superconductor sheet and in juxtaposition to the side wall. In a further embodiment of the invention, the resonators are quarter circular cylindrical plugs and each of the flat side surfaces is in contact with a juxtaposed side wall of the conductive housing through a sheet of superconductive material.

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San Ramon, CA, United States of America

Stephen C Holme