An improved element for use in array antennas

An antenna element consisting of a slot plus two parasitically excited wires has been found to exhibit many properties useful in array applications. The introduction of the wires provides a means of controlling both the
E
- and
H
-plane element radiation patterns. Specifically, the principal plane radiation patterns can be equalized and the directivity increased. If desired, the element pattern can closely approximate a
cos \theta
pattern in both planes. A 14-dB reduction in interelement mutual coupling is also achievable with this source as compared to a slot alone. A comparison of the characteristics of a four-quadrant 60-slot monopulse array with and without the wire elements indicates a 0.6-dB increase in gain and a significant reduction in back radiation for the former.