Multibeam Antenna

A multibeam antenna is antenna systems designed to generate multiple simultaneous beams from a single antenna aperture. In satellite communications, multibeam operation is used to create higher-gain spot beams, enable frequency reuse, support coverage in multiple frequency bands, and increase overall system capacity. Although multiple single-beam antennas could be used, spacecraft volume, mass, and deployment constraints generally make multibeam antennas the preferred solution.

Two principal approaches are used to realise multibeam antennas. The first is the multi-feed reflector antenna, in which a single reflector is illuminated by multiple feed horns located near the focal region. Each feed produces a separate beam on the Earth’s surface. This approach is relatively simple and well suited to a small number of beams, but the use of multiple feeds can reduce aperture efficiency and increase spillover and sidelobe levels. Multi-feed reflector antennas are also commonly employed to generate shaped beams tailored to specific geographic regions.

The second approach is the phased-array antenna, in which the relative phases and amplitudes of signals applied to individual radiating elements are controlled to form multiple beams simultaneously. Phased-array multibeam antennas avoid the mechanical complexity of multiple feed assemblies but require more complex feed networks, beamforming circuitry, and signal processing to generate and manage the required phase relationships across the array.