Com Dev Limited

Richard J Cameron

Wai-Cheung Tang

Van Dokas

David M Bryant

A microwave filter has a plurality of resonant cavities with each cavity containing a dielectric resonator. There are self-equalizing probes or self-equalizing apertures located between some of the cavities. A circulator is connected to an output of the filter. The circulator has an input/output which is connected to an equalizer. The equalizer contains a dielectric resonator that is slightly different from the dielectric resonators of the filter to permit the equalizer to be tuned at a slightly different frequency from the filter. The equalizer and self-equalizing probes or apertures are capable of being operated to reduce a dispersive slope of the filter. The filter can operate in a single mode or a dual mode. The electrical performance of the filter is superior to prior art filters, particularly in the wideband versions because the dispersive slope is reduced.

Dispersion compensation technique and apparatus for microwave filters

The invention relates to a single mode multi-cavity microwave filter that includes a housing formed with a plurality of walls which define at least two rows of side-by-side dielectric loaded cavities, wherein sequential cavities are coupled to one another via slots formed in the walls therebetween and at least one pair of non-sequential adjacent cavities are coupled via a probe. The coupling via the slots is defined mathematically as positive coupling. The probe is selectively configurable to provide positive or negative coupling relative to the sign of the slot coupling. Further, at least one non-adjacent, non-sequential pair of cavities is coupled via a second probe that may be configured to provide either positive or negative coupling relative to the sign of the slot coupling. The filter housing supports a plurality of adjustable fins which extend into the slots, one fin to each slot, to selectively adjust the size of the slot.

Folded single mode dielectric resonator filter with cross couplings

A two, three or four channel multiplexer can be operated in the TE.sub.01.delta. or HE.sub.11.delta. modes, each channel of the multiplexer has one bandpass filter, with each filter usually having a plurality of cavities. One cavity of each filter is a common cavity with all of the other filters of the multiplexer. The common cavity contains one independent dielectric quarter-cut or half-cut image resonator for each filter representing a channel of the multiplexer. Each resonator is mounted on a suitable support the common cavity provides a common junction and contains a loop coupling to couple electromagnetic energy between the various channels. The multiplexer has at least one input and at least one output. Previous microwave multiplexers have a plurality of bandpass filters arranged on a coaxial manifold. With the multiplexer of the present invention, the manifold can be eliminated. Further, at the S-band or L-band, substantial weight and volume savings can be achieved using the multiplexer of the present invention without sacrificing performance. This can be very important for space applications.

Dielectric image-resonator multiplexer

This invention relates to a modular contiguous channel multiplexer having one or more modules that produce an asymmetric filter function that is combined with responses from other modules to produce an overall symmetrical response. The multiplexer can have channels arranged in any order of relative frequencies and one or more channels can be added or removed from the multiplexer without disturbing the operation of the existing or remaining channels. A method of constructing a multiplexer involves choosing the most downstream channel first, then choosing sequentially the channel immediately upstream from the channel last chosen and choosing filters of each channel to meet certain criteria. The filters of each channel are identical to one another but are not necessarily identical to filters in adjacent channels.

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Bucks, United Kingdom

Richard J Cameron