HFSS15: Axial Ratio

Axial ratio is defined as the ratio of the major to the minor axis of the polarization ellipse.

1. E_x and E_y are orthogonal complex-valued field components. If either is zero, HFSS treats the field as linearly polarized. However, if neither E_x and E_y is zero:

2. Compute circular components E_- and E₊ from:

3. If E₊ = 0 or E_- = 0 HFSS understands the field as perfectly circular, the axial ratio is 1. Otherwise, for the elliptical polarization case, HFSS determines the tilt angle t from:

4. Rotate the original data to coincide with the axes of the polarization ellipse.

(4)

(5)

5. The Axial Ratio AR is given by:

(6)

Because the above definition does not discriminate between major and minor ellipse axes, to enforce the convention that AR< 1, it is necessary to check this condition and if necessary invert the value obtained.