About the influences of polarization agile jammers to adaptive antenna arrays

We consider a jammer signal with different polarization states. Different polarization states of the jammer signal during weight vector adaptation and during the use of this weight vector can yield a significant reduction of the jammer suppression. If the jammer polarization scenario doesn't change during the weight calculation and the weighting of the sample vectors, antenna element errors have no significant effects. With an increasing difference of the element antenna patterns, the number of needed degrees of freedom can be twice the number of jammer signals. The aims of the paper are: to call attention to the problems of polarization with respect to adaptive filtering; and to investigate the necessary equality of the radiation patterns of the element antennas.