THE LIMITATION OF MUTUAL IMPEDANCE PRECISION TO THE SIDELOBE LEVEL OF ARRAY ANTENNA

Generally speaking, an accurate mutual coupling correlation is necessaryfor an array antenna to reach ultra-low sidelobe level. If the mutual impedance or mutual coefficient matrix of an array is perfectly known, one can completely compensate the effect of mutual coupling and realize the desired low sidelobe level in theory. However, the mutual impedance matrix obtained whether by calculation 01 by measurement has a limited precision, which limits the availability of the compensation. This paper deals with the requirements on the precision of mutual impedance for compensation. in ultra-low sidelobe array antenna. The relationship between mutual impedance errors and the amplitude and phase errors of channels is derived, by which the relationship between mutual impedance error and the sidelabe level is given.