Simultaneous Measurement of Polarization and Source Direction of Plane Waves Using Three Arbitrary Antennas

Abstract

Two techniques of simultaneous measurement of source direction and polarization, using three orthogonal short dipoles, are reviewed and extended to cover partially polarized waves. One technique involves forming the real part of the 3 x 3 antenna voltage coherency matrix. The other involves forming the imaginary part of the same matrix. The concept of a transfer function matrix for an arbitrary three-port antenna is then developed. This concept allows the source direction and polarization to be measured simultaneously, using an iterative method, when antennas other than short dipoles are used. The method involves transformation of the transfer function matrix among various reference frames. A novel polarization transform is then developed which greatly improves the convergence properties of the iterative method, and which permits the wave parameters to be determined even when the waves are linearly polarized. The method requires that both the real and imaginary parts of the antenna voltage coherency matrix are formed. The method is valid for partially polarized and unpolarized waves in addition to purely polarized waves. An example, which has been simulated numerically, is also presented.