Novatel Communications Ltd.

Novatel Communication Ltd.

Andrew E McGirr

John Godfrey McRory

Paul L Camwell

Paul M Camwell

Barry J Cassidy

An antenna for use with portable duplex radio transceivers, such as those found in hand-held cellular telephones, which includes a pair of co-planar radiating patch elements elevated above a conductive surface by a conductive bar. The surface and bar define a reference ground plane which inherently isolates the patches. The patches are shaped so that they operate in a desired frequency band as well as band-pass filters--one of the patches is tuned to the transmit band and serves a transmit structure, and the other patch is tuned to the receive band and serves as a receive structure. Switching devices such as positive-intrinsic negative (PIN) diodes can be disposed along the space between the patches and the ground plane to allow each structure to be tuned. The antenna is efficient, because of inherent isolation between the receive and transmit patches, and eases the front end filtering functions traditionally performed by a duplexer. It can be completely enclosed within the chassis of a hand-held telephone.

Duplexing antenna for portable radio transceiver

A radio telephone uses a signal indicating the strength of received communication signals as a measure of prevailing signal propagation conditions to control the gain of a power amplifier in its transmitter. Where conditions are favorable, the gain can be reduced without deleterious effects on transmitted signals, and with a resulting savings in power drain on the radio telephone's power supply (e.g., batteries). In this way, talktime on a single battery charge can be significantly lengthened. Where conditions are adverse, e.g., at outlying or fringe areas of a cellular telephone system of which the radio telephone is a station, the gain can be increased to produce stronger transmitted signals, at times extending the effective coverage area of such systems. Preferably, the output of the power amplifier remains at all times within a power range prescribed by applicable standards, and is increased or decreased within the power range in accordance with prevailing conditions indicated by the received signal strength signal.

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Calgary, Canada

Andrew E McGirr