Transmission of a pulse through cylindrical waveguide

Hi,

I have modeled a cylindrical waveguide of radius, a = 38.1 mm. For this dimension, the first (TE11) and second (TM01) cut-off frequencies are at 2.3055 GHz and 3.0118 GHz, respectively. The model, has therefore, been simulated between 2.2 - 3.1 GHz.

I want to transmit a pulse through the structure, and obtain the near-field response at a specific distance from the waveguide. For this purpose, I used the analytical form of the time-domain signal (under consideration) and generated data points using MATLAB. These data points are used as the input time signal in POSTFEKO. Next, I tried observing the output response and obtained the following error message: "The simulated frequency range and signal bandwidth have insufficient overlap". The .cfx and .pfs files are attached here.

How can I observe the output response correctly?

-Thanks,

Bidisha