Low‐Cost Beam‐Reconfigurable Directional Antennas for Advanced Communications

This chapter discusses different techniques to realize low-cost beam-reconfigur-able and multi-beam directional antennas. Generally speaking, the cost of beam-reconfigurable high-directivity antennas can be reduced by addressing two of their main facets: decreasing the number of active antenna elements and avoiding the use of expensive RF components such as phase shifters. The design concepts of active frequency selective surfaces, antennas with parasitic elements, lens antennas, and antennas with metasurfaces are presented to decrease the number of active antenna elements. The design concepts of low-bit reflectarrays and transmitarrays, leaky-wave antennas, multi-beam antennas, tunable materials based array antennas, mechanical beam-steering antennas, and low-cost beamforming networks are presented to avoid the use of expensive phase shifters as essential components in array antennas. These different approaches and their specific techniques are discussed with examples and simulation or measurement results.