Motorola Corporation

David M De Muro

Raymond L Sokola

Steven R Green

Duane C Rabe

Michael F Moutrie

Phillip J Gordon

John G Stillmank

A radio frequency duplexer filter for a duplex transceiver is disclosed. To prevent spurious signals conducted by flyback responses of the transmit bandpass filter 103 from reaching the antenna (105), a band reject circuit consisting of third harmonic quarter-wave transmission line stubs (601 and 603) are advantegeously coupled to an output transmission line (107). Likewise, to prevent spurious signals conducted by flyback responses of the receive bandpass filter (113) from reaching the receiver (109), a band reject circuit consisting of third harmonic quarter-wave transmission line stubs (605 and 607) are advantageously coupled to an input transmission line (111).

Duplexer filter having harmonic rejection to control flyback

A duplexer for a radio transceiver is disclosed in which two volumes of dielectric material each have at least two holes and each is covered with a conductive material except for one surface. An electrode on the one surface of each volume is coupled to one of the holes and is coupled to a substrate via a terminal passing through a mounting device. The substrate provides coupling between the terminals of the two volumes and a common antenna.

Multiple resonator dielectric filter

A surface mount dielectric block filter with an integral transmission line connection to external circuitry is disclosed. In order to connect an input/output capacitor metallized on the surface of the dielectric block to a substrate upon which the dielectric block is directly mounted, a transmission line of appropriate characteristic impedance disposed on the surface of the dielectric block is connected between one plate of the metallized capacitor and an input/output terminal. Two such dielectric block filters may be coupled together to form a radio transceiver duplexer.

Surface mount filter with integral transmission line connection

A multiresonator dielectric block filter is disclosed in which capacitive coupling between resonators disposed in the dielectric block is controlled by an electrode strip coupled to the conductive material covering the majority of the dielectric block surface. The electrode strip extends at least partially between two adjacent resonators to control the capacitive coupling between the resonators.

A multiresonator dielectric block filter is disclosed in which capacitive coupling between foreshortened resonators disposed in the dielectric block is controlled by an electrode strip coupled to the conductive material covering the majority of the dielectric block surface. The electrode strip extends at least partially between two adjacent resonators to control the capacitive coupling between the resonators.

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Schaumburg, IL, United States of America

David M De Muro