DUPLEXING ANTENNA FOR PORTABLE RADIO TRANSCEIVER

摘要

An antenna (18) 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 (20, 30) elevated above a conductive surface (40) by a conductive bar (44). The surface (40) and bar (44) define a reference ground plane which inherently isolates the patches (20, 30). The patches (20, 30) are shaped so that they operate in a desired frequency band as well as bandpass filters-one of the patches (30) is tuned to the transmit band and serves a transmit structure, and the other patch (20) is tuned to the receive band and serves as a receive structure. Switching devices (65) such as positive-intrinsic negative (PIN) diodes can be disposed along the space between the patches (20, 30) and the ground plane (40) 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.