Radio Frequency Systems, Inc.

Alcatel Na, Inc.,

William D Blair, Jr

Salvatore Bentivenga

Gregory J Lamont

A multi-cavity dielectric filter 30 having a single housing 32 for a plurality of resonant cavities 65. The dielectric filter 30 has a plurality of dielectric resonators 42 placed inside housing 32, instead of in individual housings, wherein the resonators 42 are spaced a quarter wave apart and are electrically isolated from one another by conductive isolation plates 44 positioned therebetween. The isolation plates 44 do not make continuous mechanical contact with the interior conducting surface of housing 32, but rather are spaced from the inner surface 77 of housing 32, thereby making assembly of the filter much simpler than if a solid RF connection had to be made. The resonators 42 are positioned inside the housing 32 between the isolation plates 44 and are supported by low loss, low dielectric constant spacers 46. End walls 59 complete the cavity formation at the termination ends 79 of housing 32. For a band reject filter, the cavities are joined by coupling loops connected to a transmission line while for a bandpass filter, apertures are placed in the isolation plates (44') so as to couple electromagnetic energy between adjacent cavities (65).

Multi-cavity dielectric filter

A technique for directly coupling multiple high frequency resonant cavity filters includes a common port 62 that is directly coupled to a coupling rod 76 that is mounted within a first high frequency resonant cavity filter housing 64 of a housing assembly 60. The coupling rod 76 is directly coupled by a conductor 74 to an coupling rod 72 that is mounted within a second high frequency resonant cavity filter housing 66. The conductor 74 passes through an opening 78 in a common wall 80 between the first 64 and the second 66 high frequency resonant cavity filter housings. Thus, both filters 64, 66 are directly coupled to the common port 62.

High frequency filter having common coupling rods fixedly mounted and

A duplexing filter filters high frequency electromagnetic signals operating in two different frequency bands and uses a common coupling line mounted within an overall housing. Both filters use resonators and may be configured as combine or interdigital type filters. The high frequency filter has at least some of its resonators mounted on a base plate which in turn is positioned at a location along the length of the common coupling line so as to couple the higher frequency filter at its approximate quarter-wave location.

Duplexing filter

A dielectric notch resonator particularly suitable for use in a band reject filter operable at ultra-high frequencies comprises a dielectric resonator and an associated housing which results in a reactance having an imaginary component effectively nulled by a coupling reactance mechanism forming part of the dielectric notch resonator so as to present a relatively low resistive impedance load at a given center frequency and frequencies in a narrow bandwidth thereabout. The coupling reactive mechanism comprises an inductive wire and a serially connected variable capacitor so as to null the reactive component of the dielectric resonator at a particular center frequency and to modify the symmetry of the rejected frequency bandwidth by adjusting the capacitance of the variable capacitor.

Dielectric notch resonator

A dielectric notch filter for attenuating frequencies of relatively narrow bandwidth in comparison to the center frequency of operation, and particularly for attenuating such narrow bandwidths in the ultra-high frequency electromagnetic spectrum. The dielectric notch filter comprises a plurality of dielectric notch resonators coupled to a transmission line at slightly less than the quarter wavelength of the center frequency of the attenuation frequency bandwidth so as to minimize interaction between the individual dielectric notch resonators. Each dielectric notch resonator comprises a dielectric resonator, an associated housing and a coupling reactance element which in turn comprises an inductive wire and a variable capacitor so as to null the reactive component of the dielectric resonator, thereby resulting in a highly attenuated resonant frequency having little imaginary component about said center frequency. By use of a plurality of such dielectric notch resonators, a bandwidth of frequencies can be attenuated through coupling of each resonator to the transmission line.

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Lanoka Harbor, NJ, United States of America

William D Blair, Jr