device for determining the direction of incidence of electromagnetic waves, in particular radarimpulsen

摘要

An antenna array for direction determination comprises two pairs of elongated end-firing log-periodic antenna elements 1, 2 and 3, 4, each pair fixed symmetrically to a reference plane 5 and forwardly convergent to it. The two antenna elements of one pair converge forwardly at an angle b, those of the other pair converge at an angle a = 1.5 b. From the detected and amplified signals of each pair there is obtained a difference signal designated L1, for the b-angle pair, L2 for the a-angle pair. A third difference signal L3 is obtained from L2-L1. The magnitude of each difference signal depends upon value of an angle V between a boresight axis 12 and a detected radiation source. An indication of V is taken on the basis of L1 if L1, L2 and L3 are on the same side of zero. A more precise indication of V is then taken on the basis of L2 by comparing absolute value of L2 with the absolute value of an adjustable reference signal. IMAGE