Local compensation of failed elements of an active antenna array

DETAILED DESCRIPTION Accordingly, it is an object of the invention to improve antenna systems; It is another object of the invention to improve performance of active antenna arrays; It is another object of the invention to simplify and reduce the overall cost of such arrays; It is another object of the invention to provide a method for compensating for failed elements of an active antenna array; It is another object of the invention to provide such a method while avoiding a steepest descent, global compensation approach; and It is still another object of the invention to increase the working lifetime of active antenna arrays.
According to the invention, local compensation is provided for failed elements of an active antenna array.
The local method applies a simple phase and amplitude weight adjustment for the nearest neighbors above and below the failed element, requiring no storage of complex weights and working incrementally for each failure.
According to the invention, nearest neighbor element voltage increments form a small compensation subarray scanned toward the ground, cancelling out the error produced by the failed element at a particular depression angle.
The average sidelobe level in the vicinity is also reduced.
The approach according to the invention uses the concept of a differential antenna pattern.
The differential pattern is that part of the antenna pattern produced by the failure or compensator elements alone.
The sum of the failure and compensator differential patterns is minimized toward the ground, rather than the total pattern from all the elements.
In practice, this means that each time an antenna element fails, compensation is added to a subarray of its nearest neighbors.
When the next element fails, the new compensation generally has no effect on the scheme for the previously failed elements.
Similarly, the previous compensation generally has no effect on the compensation for the latest failure.
The local compensation method is particularly advantageous in cases where the antenna beam is electronically scanned in different directions