Flat plate antennas with sector coverage

Antennas for macro and micro cell base stations in personal communication networks need to provide specified angular coverage in both azimuth and elevation. A simple example is a colinear array of vertical dipoles with a corner reflector. Some important properties of interest are control of azimuth beamwidth over a frequency band, provision for elevation beamforming, minimum size and hence environmental impact, and low manufacturing cost. Designs are favoured which allow re-use of a common core with variations of a secondary structure (e.g. the reflector) to vary the azimuth beamwidth. The first antenna design presented is aimed at minimising the antenna size while allowing control of the azimuth beamwidth and maintaining a good front to back ratio. A second, more complex, design allows polarisation diversity with matched beamwidths for two polarisations