A Shaped and Reconfigurable Reflector Antenna With Low Sidelobe Level for Cellular Wireless Communications

This letter presents a shape synthesis and an array optimization of the hourglass reflector antenna. A cosecant-squared pattern in the elevation plane, with the reconfigurable beamwidth in the horizontal plane, is achieved by controlling the excitation of the feed array elements and maintaining an invariable reflector surface. Thus, a sectorial pattern configuration of four beams (with 90 beamwidth) or eight beams can be selected in the azimuth plane. Both kinds of patterns (vertical and horizontal) have proven their usefulness and advantages for base stations in wireless communication systems.

I. Introduction

Wireless communications have shown significant growth in recent years. One parameter used to measure the efficiency of a wireless system is the ratio between the carried and the offered traffic to the network. In this way, it is well known that the utilization of reconfigurable antennas makes possible simultaneous change in beamwidth and number. Consequently, the carried traffic is increased and the global efficiency of the system [1] is improved. Feasible solutions for omnidirectional patterns, by using shaped reflector antennas, were proposed in [2]–[5] as a good solution for rural areas where the reconfigurability of the antenna would not be required. On the other hand, an hourglass reflector antenna fed with a horn cluster producing reconfigurable beams was proposed in [6]. The latter approach was improved in [7] by shaping the reflector surface in order to achieve cosecant-squared pattern in the elevation plane.