Variable beamwidth shorted patch antenna array for indoor positioning

Variable beamwidth antennas can optimize the radio coverage of a transmitter for indoor positioning. In this study, we developed a small variable beamwidth antenna array suitable for indoor positioning that is comprised of electrically small shorted patch antennas and is adapted for use with the indoor messaging system (IMES). We did theoretical calculations and experimental measurements to examine the antenna properties. Our results showed that beamwidth variations from 40° to 65° can be obtained and that the boresight gain is adequate for use with IMES transmitters.