Mutual coupling coefficients in collector arrays on circular cylindrical concave surfaces

An analysis is presented of mutual coupling in collector arrays on a concave side of a large conducting circular cylindrical surface. The collector elements are uniformly spaced narrow axial slits which are parallel-plate-guide-fed in the TEM mode. Each element is equipped with a matching network appropriate to broadside scan in the corresponding planar slit array. The properties of coupling coefficients are studied numerically. It is shown that for spacing less than , past a certain curvature dependent neighborhood of the excited element, the rate of decay of the -plane coupling coefficients is considerably slower than in a planar array with the same elements and spacing. The slower decay of coupling coefficients should be considered in evaluation of the efficiency of collector arrays on concave surfaces. For the dependence of coupling coefficients on the distance exhibits considerable fluctuations which are attributed to grating-lobe formation. It is also shown that the collector element mismatch may be enhanced by the collector cavity resonances, so that the criteria for admissible voltage standing-wave ratio (VSWR) level of collector elements may be more stringent than in planar arrays.