AddPlaneWaveExcite
==================
```{function}  AddPlaneWaveExcite(CSX, name, k_dir, E_dir, <f0, varargin>)
```
Full definition:
```{code-block} matlab
function CSX = AddPlaneWaveExcite(CSX, name, k_dir, E_dir, <f0, varargin>)
```

Creates a plane wave excitation in the sense of a total-field/scattered
field approach.

Note: A plane wave excitation must not intersect with any kind of
material. This exctiation type can only be applies in air/vacuum and
completely surrounding a structure!!!

Note: Only a single Box can be applied to this property!!

Arguments
- CSX:   CSX-struct created by InitCSX
- name:  property name for the excitation
- k_dir: unit vector of wave progation direction
- E_dir: electric field polarisation vector (must be orthogonal to k_dir)
- f0:    frequency for numerical phase velocity compensation (optional)

example:

    inc_angle = 0 /180*pi; %incident angle on the x-axis
    k_dir = [cos(inc_angle) sin(inc_angle) 0]; % plane wave direction
    E_dir = [0 0 1]; % plane wave polarization --> E_z
    f0 = 500e6;      % frequency for numerical phase velocity compensation
    
    CSX = AddPlaneWaveExcite(CSX, 'plane_wave', k_dir, E_dir, f0);



-----------------------
author: Thorsten Liebig

See also AddExcitation, AddBox