A BEAM TILT DIPOLE ARRAY ANTENNA FOR INDOOR MOBILE APPLICATIONS

A new beam tilt dipole array antenna in a simple structure has been de veloped for indoor base stations in the 1.9 GHz band. The antenna comp rises a radiator and skewed off-center parasitic elements placed aroun d the radiator. With this stucture, the main beam of the array antenna can be tilted for mobile terminals reception by the effect of mutual coupling. Studies on tilt characteristics for antenna dimensions and t ilt mechanism by precise current measurements have clarified the opera ting principle. The antennas with a fan beam and an omnidirectional pa ttern have been designed. The measured tilt angle was varied in the ra nge of 9 to 26 degrees with little alteration of the horizontal radiat ion patterns.