ANTENNAS FOR SAFER HAND-HELD RADIOS

摘要

An antenna for a personal communication device designed for reducing RF emissions to a user's head and body comprises a single half-wave dipole antenna element (20) mounted on the top of a telescoping rod (22) such that the antenna element (20) is raised above the user's head (18) when the rod (22) is extended. The rod (22) is completely inactive and serves only to elevate the active antenna element (20) above the user's head and away from the body. A built-in switch (30) is provided which reduces the transmission RF power when the rod (22) is retracted to further protect the user. In a second embodiment, a co-linear array of dipole antenna elements (38) is used. The full array is active for reception. However, a proximity detector (50) senses the proximity of a human body, and lowers the RF transmission power to those antenna elements (38) in the array that are closest to the user's head.