Introduction_to_Smart_Antennas_C._A._Balanis_P

  In recent years a substantial increase in the development of broadband wireless access technologies for evolving wireless Internet services and improved cellular systems has been observed [1]. Because of them, it is widely foreseen that in the future an enormous rise in traffic will be experienced for mobile and personal communications systems [2]. This is due to both an increased number of users and introduction of new high bit rate data services. This trend is observed for second-generation systems, and it will most certainly continue for third-generation systems. The rise in traffic will put a demand on both manufacturers and operators to provide sufficient capacity in the networks [3]. This becomes amajor challenging problem for the service providers to solve, since there exist certain negative factors in the radiation environment contributing to the limit in capacity