$G(x,y,\omega ,\sigma ,\gamma ,\theta ) = \frac{1}{{\sqrt {\pi \gamma \sigma } }}e^{ - \frac{1}{2}\left[ {\frac{{\left( {\gamma R_1 } \right)^2 + R_2^2 }}{{\left( {\gamma \sigma } \right)^2 }}} \right]} e^{i\omega R_1 }$
$R_1 = x \cdot \cos \theta + y \cdot \sin \theta ,R_2 = - x \cdot \sin \theta + y \cdot \cos \theta$