phased array antennas
wide null generation
A.M. Shitikov, A.V. Sablin
One of the pressing problems of forming beams with phased array antennas is suppressing interference. When the direction of the interference is known, the method of partial diagrams (Woodwards method) can be successfully applied. This technique uses two beams, one of which is directed towards the goal or the desired signal and the other in the direction of interference. The result of these individual partial beams is the creation of a complete aggregate beam.
The forming null achieved in this way is deep enough, however it also turns out to be thin, so inhibition of undesired signals is possible only in narrow bands. Widening of the useful band depends on range of forming null.
Three correcting beams with special shapes work well to extend the band of signal. Each beam has a value equal in the correcting point and the null in the neighboring points. In one step a correction beam is created in one direction with the help of one correcting antenna pattern.
In view of the relatively small adjustments, distortion of the main beam does not occur, even despite the high level of the correcting pattern in the area of the main beam.