Prented dipole array fed by a slotline

Abstract

A printed dipole array fed by a slotline is newly presented and analyzed. The proposed antenna consists of printed dipoles as a radiator and of a slotline as a feeder. To obtain a practical gain, a linear dipole array is constructed by placing printed dipoles periodically above the slotline. A simple theory is used to calculate the radiation pattern and the input admittance of this array. A magnetic surface current above a perfectly conducting plane equivalent to a slotline exitation is considered in the presence of the equivalent wire dipoles. A set of integro-differential equations are formulated for unknown currents on the equivalent wire dipoles excited by the strip magnetic current on the perfectly conducting plane. The moment method is applied to evaluate current distributions in the dipoles. Equivalent radiating admittance of the printed dipple seen from the slotline is also calculated and measured for various values of lengths and heights of the dipole above the slotline. Printed dipole array of uniformly tapered aperture distribution as well as the raised cosine tapered one are designed by using the simplified theory and fabricated. Measured radiation pattern of these dipole arrays are closely compared with the calculated patterns.