CST2013 MWS Examples: Waveguide Filter With Photonic Bandgap Material

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General Description

This example shows the S-parameter calculation of a waveguide filter based on a photonic bandgap material. The photonic bandgap material consists of small metallic disks embedded in a dielectric material.

Structure Generation

The single components of the device are created as bricks and cylinders. Identical parts are mirrored or translated. Many parts of the structure are modelled parametrically allowing to change the structure easily.

Solver Setup

In order to enable a transient calculation, two waveguide ports are defined with their reference plane moved to the photonic bandgap material. The device is examined over the frequency range from 25 to 45 GHz using the standard Gaussian signal.

To reduce the simulation time, magnetic and electric symmetry planes are used in the YZ- and the XZ-plane, respectively. Moreover, since the waveguide filter represents a resonant structure, the auto-regressive filter (AR-filter) is activated. The AR-filter allows to obtain accurate results even before steady state is reached. Especially for highly resonant models, this can save a huge amount of calculation time.

In order to get a visualization of a monochromatic wave propagation, 3D monitors of the electric and magnetic fields are defined at one resonance frequency.

Post Processing

Performing a transient calculation using waveguide ports, the resulting time signals are converted automatically into the desired scattering parameters. All these results are listed in the navigation tree in the folder 1D Results and demonstrate the wave propagation in the filter indicating a proper excitation frequency for monochromatic operation.

The results of the electric and magnetic field monitors are stored in the folder 2D/3D Results where also the calculated port modes of the given waveguide ports can be examined.