Abstract: This invention provides a notch filter including a main transmission line, a coupling mechanism, and at least one electrically tunable resonator coupled to the transmission line through the coupling mechanism. A tunable dielectric varactor or a microelectromechanical variable capacitor is provided in each of the resonators.

Abstract: An embodiment of the present invention provides n apparatus, comprising a wireless telephone handset comprising an antenna connection; a diplexer coupled to the antenna connection; a transmit section connected to a first port of the diplexer; a receive section connected to a second port of the diplexer; and wherein the diplexer includes first and second notch filters, each of the notch filters comprising a main transmission line, a first coupling mechanism, and a first electrically tunable resonator coupled to the main transmission line through the first coupling mechanism, wherein the first electrically tunable resonator includes a voltage tunable dielectric varactor and wherein a control unit provides control signals for controlling the voltage tunable dielectric varactor, thereby tuning the first and second notch filters to provide isolation between the transmit and receive frequencies.

Abstract: This invention provides a notch filter including a main transmission line, a coupling mechanism, and at least one electrically tunable resonator coupled to the transmission line through the coupling mechanism. A tunable dielectric varactor or a microelectromechanical variable capacitor is provided in each of the resonators. Wireless telephone handsets that include the filter are also included.

Abstract: An electronic filter includes a first microstrip line hairpin resonator including first and second arms, a first varactor connected between a first end of the first arm and a first end of the second arm of the first microstrip line hairpin resonator, a first capacitor connected between a second end of the first arm and a second end of the second arm of the first microstrip line hairpin resonator, the first and second arms being coupled to provide a first transmission zero, an input coupled to the first microstrip line hairpin resonator, a second microstrip line hairpin resonator including third and fourth arms, a second varactor connected between a first end of the third arm and a first end of the fourth arm of the second microstrip line hairpin resonator, a second capacitor connected between a second end of the third arm and a second end of the fourth arm of the second microstrip line hairpin resonator, the third and fourth arms being coupled to provide a second transmission zero, and an output coupled to th

Abstract: A duplexer is provided that includes a first tunable bandpass filter, a second tunable bandpass filter and means for coupling the first bandpass filter and the second bandpass filter to an antenna. The duplexer is operated by tuning the first tunable bandpass filter to provide a passband corresponding to an assigned transmit frequency, and tuning the second tunable bandpass filter to provide a passband offset from an assigned receive frequency, when the duplexer is operated in a transmit mode. When the duplexer is operated in a receive mode, the first tunable bandpass filter is tuned to provide a passband offset from an assigned transmit frequency and the second tunable bandpass filter is tuned to provide a passband corresponding to the assigned receive frequency.

Abstract: An electronic filter includes a substrate, a ground conductor, a plurality of linear microstrips positioned on a the substrate with each having a first end connected to the ground conductor. A capacitor is connected between a second end of the each of the linear microstrips and the ground conductor. A U-shaped microstrip is positioned adjacent the linear microstrips, with the U-shaped microstrip including first and second extensions positioned parallel to the linear microstrips. Additional capacitors are connected between a first end of the first extension of the U-shaped microstrip and the ground conductor, and between a first end of the second extension of the U-shaped microstrip and the ground conductor. Additional U-shaped microstrips can be included. An input can coupled to one of the linear microstrips or to one of the extensions of the U-shaped microstrips. An output can be coupled to another one of the linear microstrips or to another extension of one of the U-shaped microstrips.

Abstract: Dielectric tube loaded metal cavity resonators and filters having a dielectric tube resonator extending substantially the full height of the metallic cavity are disclosed herein. The resonators and filters achieve low insertion loss in a size substantially smaller than conventional dielectric loaded resonators for equivalent quality factors. The dielectric tube resonators may be used with coaxial resonators to provide mixed resonator filter constructions.

Abstract: A method is provided for operating a duplexer including a first tunable bandpass filter, a second tunable bandpass filter and means for coupling the first bandpass filter and the second bandpass filter to an antenna. The method comprises the steps of tuning the first tunable bandpass filter to provide a passband corresponding to an assigned transmit frequency, and tuning the second tunable bandpass filter to provide a passband offset from an assigned receive frequency, when the duplexer is operated in a transmit mode. When the duplexer is operated in a receive mode, the first tunable bandpass filter is tuned to provide a passband offset from an assigned transmit frequency and the second tunable bandpass filter is tuned to provide a passband corresponding to the assigned receive frequency.

Abstract: A method is provided for operating a duplexer including a first tunable bandpass filter, a second tunable bandpass filter and means for coupling the first bandpass filter and the second bandpass filter to an antenna. The method comprises the steps of tuning the first tunable bandpass filter to provide a passband corresponding to an assigned transmit frequency, and tuning the second tunable bandpass filter to provide a passband offset from an assigned receive frequency, when the duplexer is operated in a transmit mode. When the duplexer is operated in a receive mode, the first tunable bandpass filter is tuned to provide a passband offset from an assigned transmit frequency and the second tunable bandpass filter is tuned to provide a passband corresponding to the assigned receive frequency.

Abstract: An electronic filter includes a first microstrip line hairpin resonator including first and second arms, a first varactor connected between a first end of the first arm and a first end of the second arm of the first microstrip line hairpin resonator, a first capacitor connected between a second end of the first arm and a second end of the second arm of the first microstrip line hairpin resonator, the first and second arms being coupled to provide a first transmission zero, an input coupled to the first microstrip line hairpin resonator, a second microstrip line hairpin resonator including third and fourth arms, a second varactor connected between a first end of the third arm and a first end of the fourth arm of the second microstrip line hairpin resonator, a second capacitor connected between a second end of the third arm and a second end of the fourth arm of the second microstrip line hairpin resonator, the third and fourth arms being coupled to provide a second transmission zero, and an output coupled to th

Abstract: This invention provides a notch filter including a main transmission line, a coupling mechanism, and at least one electrically tunable resonator coupled to the transmission line through the coupling mechanism. A tunable dielectric varactor or a microelectromechanical variable capacitor is provided in each of the resonators. Wireless telephone handsets that include the filter are also included.

Abstract: An electronic filter includes a substrate, a ground conductor, a plurality of linear microstrips positioned on a the substrate with each having a first end connected to the ground conductor. A capacitor is connected between a second end of the each of the linear microstrips and the ground conductor. A U-shaped microstrip is positioned adjacent the linear microstrips, with the U-shaped microstrip including first and second extensions positioned parallel to the linear microstrips. Additional capacitors are connected between a first end of the first extension of the U-shaped microstrip and the ground conductor, and between a first end of the second extension of the U-shaped microstrip and the ground conductor. Additional U-shaped microstrips can be included. An input can coupled to one of the linear microstrips or to one of the extensions of the U-shaped microstrips. An output can be coupled to another one of the linear microstrips or to another extension of one of the U-shaped microstrips.

Abstract: A method is provided for operating a duplexer including a first tunable bandpass filter, a second tunable bandpass filter and means for coupling the first bandpass filter and the second bandpass filter to an antenna. The method comprises the steps of tuning the first tunable bandpass filter to provide a passband corresponding to an assigned transmit frequency, and tuning the second tunable bandpass filter to provide a passband offset from an assigned receive frequency, when the duplexer is operated in a transmit mode. When the duplexer is operated in a receive mode, the first tunable bandpass filter is tuned to provide a passband offset from an assigned transmit frequency and the second tunable bandpass filter is tuned to provide a passband corresponding to the assigned receive frequency.

Abstract: A dielectric loaded cavity filter having a housing and a cover and defining at least two adjacent cavities having respective dielectric resonators mounted therein and separated by a transverse partition defining a coupling window in the housing. In one form, the coupling window has two spaced opposing sidewalls confronting each other, and vertically offset shoulders intermediate their length. A conductive coupling strip is secured to the shoulder of one sidewall and extends across the coupling window and over the shoulder of the other sidewall. A tuning screw is secured by threading to the housing and has an outer free end accessible from the exterior of the filter, and an internal end disposed adjacent the coupling strip, whereby when the tuning screw is rotated, the internal end of the screw moves toward and away from the coupling strip in a direction perpendicular to the cover for tuning without requiring access to the coupling strip.

Abstract: A dielectric resonator loaded cavity filter comprises a housing having an exterior and an interior, the housing interior including at least two adjacent cavities having dielectric resonators mounted therein. The adjacent cavities are separated by a transverse partition having a coupling window therein, the coupling window having first and second spaced opposing sidewalls. In one embodiment a coupling disk is interposed between opposing sidewalls of the transverse partition. In another embodiment a coupling strip extends from a shoulder portion of a first opposing sidewall toward a shoulder portion of a second opposing sidewall.