2.17.2    Plane TEM example

There are a few methods of TEM wave excitation in QW-3D. In principle, choice of a particular excitation depends on whether it is an open air region where the plane wave box is applicable (see Plane wave excitation and scattering) or transmission line where the port with TEM wave excitation has to be defined.

In this Section we present a plane TEM wave excitation which is a more efficient method compared to the TEM wave one presented in A parallel-plate transmission line when the port is electrically large so the quasistatic template generation may be quite time consuming. Consider the scattering of the normally incident plane wave from a two dimensional rectangular metal grating. Open …\Scattering\PlaneTEM\plane_tem.pro. In a 2D Window (see Fig. 2.17.2-1) the scenario consists of 5x5 grating with the excitation port above. In order to allow the plane TEM excitation we put the grating inside the parallel plate transmission line.

Run the simulation using  button from Simulation tab of QW-Editor. In the Results window (invoked upon pressing  button in Results tab of QW-Simulator) we may watch the |S11| curve as a reflection coefficient of 0^th order (see Fig. 2.17.2-2). The rest of the incident power has been scattered to the higher diffraction orders.

Fig. 2.17.2-1   2D window of the plane_tem.pro model.

Fig. 2.17.2-2  0^th order reflection coefficient.