Phased array fundamentals

Phased arrays are a major class of antennas which offer many important features such as electronic beam scanning. Their flexibility has to be assessed against their complexity and cost. The fundamental principles of a phased array are described. The properties of radiating apertures are given first, as these are basic to both aperture antennas and arrays as sampled apertures. Linear array analysis then introduces beam steering and null steering. Array beamforming shows how array excitation is controlled. This is followed by discussion of the effects of systematic or random excitation errors. Planar array analysis includes different array grid structures and the important topic of mutual coupling. Finally active arrays are briefly introduced