М.W. Indenbom

Dual-polarized phased array antennas (PAAs) are widely used in radar and wireless communications. more and more often they use radiating elements with two inputs for different polarization. An infinite periodic plane PAA of two-input dual-polarized non-dissipative elements is studied in this paper. Active element's H- and V-input patterns are related with realized scattering matrix of that element by the expression, which is obtained here for grating lobes' free beam steering sector and is based on dissipation absence condition in the system. It follows from this expression, that the active element's patterns are orhtogonality polarized in case of matched element's inputs as well as decoupled inputs. Orthogonal polarization of the active element patterns can be realized if decoupling and matching input network is implemented. Unorhtogonality factor of element's inputs is expressed through scattering matrix coefficients. It is shown that the level of cross-polarization is proportional to product of coupling and the reflection coefficients, it is a second-order infinitesimal value of scattering matrix coefficients. It is shown that the receive mode radiator's efficiency depends on incident wave's polarization. The efficiency varies between minimum and maximum singular values of the transmission matrix. The singular values are expressed from the scattering matrix's coefficients. General expression of PAA's transmission matrix is obtained by decomposition of transmission matrix by singular values and the polar decomposition of the scattering matrix. It is shown that non-coherent detection radar equipped with dual-polarized phased array antenna, which sums up the powers of polarization cannel outputs, loses 3 dB in signal/noise ratio comparing to coherent radar which coherently sums up optimally weighted voltage outputs of polarization channels. The expression is obtained for that optimal weighting vector. If the incident wave's polarization is known, then optimal weighting vector can be found and used in signal processing. If incident wave's polarization is unknown, then it is necessary either to estimate it, or to find the optimal weighting vector in adaptation procedure, or to use non-coherent detection. The last is optimal in case of random incident wave's polarization vector in sense the maximum likelihood ratio.