The Basic Theory of Phased Arrays with A Discussion of the Blind Angle

This report reviews the underlying theory of the phased array and then examines one of its most limiting problems--the blind angle. The theory of the phased array is developed by studying a simple two element array and then progressing to multi-element arrays. Following this, the progressive phase shift is incorporated into the driving currents and its result examined. The blind angle phenomenon is presented and then a physical reason for its occurrence is sought. The mutual coupling concept is demonstrated by examining mutual impedance as a function of spacing. Then the two predominate theories, surface wave and modal, offering a physical insight into the phenomenon are examined. Considerable attention is devoted to the Ghost Mode Hypothesis of Oliner, et al. and the work of Louis Stark.