Figure 2.

(a) Example of the E-field magnitude estimation process: Unit E-field (red) on the plane is projected onto all of unit vectors ${\widehat{p}}_1$ to ${\widehat{p}}_8$. Since constraints are applied to all projections, the maximum of all projections is the E-field magnitude b estimate. (b) Example of the approximation of energy constraints. The feasible region for s_j is above red the dashed curve and below the blue line; its piece-wise linear approximation is shown with green lines.