Linear van Atta Reflector Consisting of Four Half-Wave Dipoles

摘要

A Theoretical and numerical investigation of a linear Van Atta reflector consisting of 4 parallel half-wave dipoles with the same distance between adjacent elements has been made. An expression for the reflected field has been found by considering each dipole as a receiving and transmitting antenna matched to its transmission line. Mutual impedances are taken into account. In order to study the general form of the reradiation pattern analytically the mutual impedances were at first neglected. The analysis reveals, among other things, that the direction of maximum reflection often is not back in the direction of arrival of the incident field, and that for some lengths of the transmission lines and directions of arrival, the reflected field is zero. Numerical calculations have been made with a half wavelength spacing between the elements. It turns out that the induction usually introduces asymmetry into the reradiation pattern. This means that it is possible to increase the radiation back in the direction of arrival by properly choosing the distance between the dipoles and the length of the transmission lines. When the spacing between the dipoles is a half wavelength the most suitable length has been found. (Author)