Changes

To treat an object with an arbitrary geometry using PO, the object is first decomposed into many small elementary patches or cells, which have a simple geometry such as a rectangle or triangle. Then, using the tangent plane approximation, the equivalent electric and magnetic surface currents, '''J(r)''' and '''M(r)''', on the lit region of the scatterer are approximated by:

:<math> \mathbf{J(r)} = \mathbf{\hat{n}\times} \begin{bmatrix} 1-\Gamma_{||} & 0 \\ 0 & 1-\Gamma_{\perp} \end{bmatrix} \cdot \begin{bmatrix} \mathbf{H_{||}^{inc}(r)} \\ \mathbf{H_{\perp}^{inc}(r)} \end{bmatrix} </math>

:<math> \mathbf{M(r)} = -\mathbf{\hat{n}\times} \begin{bmatrix} 1+\Gamma_{||} & 0 \\ 0 & 1+\Gamma_{\perp} \end{bmatrix} \cdot \begin{bmatrix} \mathbf{E_{||}^{inc}(r)} \\ \mathbf{E_{\perp}^{inc}(r)} \end{bmatrix} </math>