OMNIDIRECTIONAL DIPOLE ANTENNA

The invention is a novel antenna configuration that has a substantially smaller size than existing antennas tuned to a given frequency. Compact size is provided without substantial loss in performance, making the antenna particularly suitable for hand-held devices. An antenna in accordance with the invention is preferably situated on an FR4 substrate, and includes a dipole having first and second pairs of copper radiating strips, one pair on each of the top and bottom surfaces of the substrate. Each radiating strip in a pair has a copper conductive strip coupled thereto, the strip of one radiating element being situated on the same surface of the substrate as the respective strip, with the conducting element of the other radiating strip being disposed on the opposite surface of the substrate. The effect of the configuration is to lengthen the radiating strips without an increase in substrate dimensions, thereby allowing tuning to low frequencies for a given substrate size. An on-board matching network includes adjustable capacitance and inductance to match the impedance of the antenna with that of a connector coupled to an off-substrate transceiver. A preferred implementation for a 900 MHz antenna is described.