An efficient approach for the power synthesis of conformal arrays with constraints in near-field

This paper addresses the problem of determining the element excitation of a conformal array such that it satisfies null-field constraints in a near-field region and produces a radiation pattern closely approximating an a priori prescribed far-field pattern. Such a problem is solved as a problem of finding the intersection between the set of all far-field patterns that can be radiated by the considered array and the set of all functions fulfilling the pattern requirements. An alternating projection method, based on the concept of projection operator, is used to this end. The near-field constraints are introduced as additional requirements in the synthesis process by imposing the condition that the tangential component of the electric field be equal to zero at some given points on a spherical surface containing the considered region. Number and position of these points are fixed by a nonredundant sampling representation of the radiated field, thus remarkably reducing the numerical complexity of the procedure.