Effect of mutual coupling on the sensitivity of dual polarized receivers in satellite communications

Dual circular polarization (CP) services are growing in popularity in satellite communications applications. Ground terminals with linearly polarized dish antenna feeds routinely achieve high port isolation between polarizations, but dual CP feeds suffer from higher coupling between ports associated with orthogonal polarizations, particularly for planar microstrip antennas used in electronically beamsteered phased arrays and array feeds. To enable optimal design of CP feeds for satellite ground terminal receivers, an analysis of the effect of mutual coupling on the sensitivity of dual polarized receivers was used to obtain a quantitative relationship between coupling and receiver sensitivity.