antennearrays

An antenna array is a group of radiating elements arranged so that their individual fields combine to form a controlled overall radiation pattern. The pattern results from the element patterns and the array factor, which depends on geometry, relative phase, and amplitude. By adjusting phase and amplitude, the main lobe can be steered toward a desired direction while reducing energy in other directions.

Common configurations include linear arrays, planar arrays, circular arrays, and conformal arrays that follow a curved surface. Spacing is typically around half a wavelength to balance angular resolution and avoid grating lobes. Elements can be dipoles, patch antennas, or other radiators, and may be passive or active with built-in amplifiers.

Beamforming is central to antenna arrays. In phased arrays, electronic phase shifters steer the beam without moving parts. Amplitude weighting shapes sidelobes and aperture efficiency. Adaptive beamforming uses signal-processing algorithms to suppress interference and optimize gain in the intended direction.

Performance metrics include directivity and gain, beamwidth, sidelobe level, and scan range. Mutual coupling between elements and manufacturing complexity are important design considerations. Grating lobes can appear if spacing is too large and limit the usable scan range.

Applications span radar and military communication systems, wireless networks (including base stations and satellite links), radio astronomy, and navigation systems. Antenna arrays enable fast electronic steering, improved link reliability, and scalable, high-gain antennas for diverse operating environments.