Hello,
I have a confusion with assigning a port in HFSS. What should be the height and width of the port for printed antennas, lets say a patch antenna or any other antenna. When I keep the width of the rectangle equal to the width of the microstrip line and height equal to the substrate height, i get some results which change when i change the dimensions of the port. How do I know which results are correct?
Please explain!! Thanks.
Referencing to the port sizing guidelines of Ansys [1], this depends on the type of port.
I suppose you are using a waveport at a grounded microstrip line. The Port should be 10* microstrip width for wide striplines (w=>h) and ~5* microstrip width or (3...4)* substrate height for narrow striplines (w
@daniel. Thanks a lot for the input. Is this true for a lumped port too?
Ansys recommends to use lumped ports for ports, which are internal to the model, only. All exterior surfaces through which a the signal enters the structure shall be modeled as wave ports.
Anyways, if you define a lumped port on a grounded microstrip line, it is as wide as the strip and its height equals the substrate thickness. This way the rectangular lumped port touches the ground as wells a the stripline.
Furthermore, you renormalize lumped ports to the desired port impedance. If this value is different from the real port impedance, the results you'll get additional reflections. Finally, the real S11 will not match the simulated one.
Best regards,
Daniel
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