Shaping Electric Field Intensity via Angular Spectrum Projection and the Linear Superposition Principle

Shaping the intensity distribution of radiated electromagnetic (EM) fields in a given bounded target area is a challenging problem in EMs. Although some approaches have been explored for this purpose, most are limited to the synthesis of plane-wave fields or point-focused fields. In this communication, a field-shaping method based on angular spectrum projection and the linear superposition principle is presented. The proposed method allows radiated electric fields to be shaped with different desired intensity patterns in a given limited target area with the use of the same antenna array. Via this method, all element excitations of the antenna array can be analytically calculated, and not only is the element excitation computational time reduced, but the real-time control of shaped fields is also made possible. Full-wave simulations were carried out to illustrate the 1-D and 2-D electric field shaping within a small given target area. In the 1-D case, three types of shaped fields with different desired distributions are demonstrated. In the 2-D case, three kinds of origin-symmetric shaped fields with different intensity distributions are illustrated. Finally, shaped fields with more complicated 2-D intensity distributions, like “I”- and “X”-shaped patterns, are demonstrated, and are achieved directly by applying the linear superposition principle to multiple point-focused fields with spatially overlapping focal spots.