Pattern control antennas for wireless access systems

Pattern control antennas are defined as the antennas designed their radiation patterns to enhance the radio channel performance of the systems. In wider meanings, static antenna pattern controls like shaped beams and low sidelobes are included in this category. However, dynamic pattern controls are more effective to improve the radio channel performance, especially in broadband and mobile wireless systems. In this, first the necessity of pattern control antennas is described for the wireless access systems. Second, the candidates of pattern control antennas to satisfy the requirements of the system are presented. Next, practical examples, which are multi-sector beam switching antennas, are introduced and the principal characteristics of the antennas are described.