APPLICATIONS OF ANTENNA-ARRAYS TO MOBILE COMMUNICATIONS .1. PERFORMANCE IMPROVEMENT, FEASIBILITY, AND SYSTEM CONSIDERATIONS

The demand for wireless mobile communications services is growing at a n explosive rate, with the anticipation that communication to a mobile device anywhere on the globe at all times will be available in the ne ar future. An array of antennas mounted on vehicles, ships, aircraft, satellites, and base stations is expected to play an important role in fulfilling the increased demand of channel requirement for these serv ices, as well as for the realization of the dream that a portable comm unications device the size of a wristwatch be available at an affordab le cost for such services. This paper is the first of a two-part study . It provides a comprehensive treatment, at a level appropriate to non specialists, of the use of an antenna array to enhance the efficiency of mobile communications systems. It presents an overview of mobile co mmunications as well as details of how an array may be used in various mobile communications systems, including land-mobile, indoor-radio, a nd satellite-based systems, It discusses advantages of an array of ant ennas in a mobile communications system highlights improvements that a re possible by using multiple antennas compared to a single antenna in a-system, and provides details on the feasibility of antenna arrays f or mobile communications applications.