Antenna feed gap capacitance

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

When using a voltage source to excite an antenna, will the FEKO-computed input impedance include the capacitance of the assumed gap between the feed terminals of the antenna? If so, what does the capacitance represent? Is it the capacitance of a hollow cylinder, or the capacitance of a solid cylinder, or something different?  Feed gaps are tricky...

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Answers

  • JIF
    JIF
    Altair Employee
    edited May 2018

    Hello EMCanuck1,

     

    Voltage sources can be added on segments (vertex port or segment port) or on the edge between triangle faces (edge port) or on microstrip ports (not applicable for your question). Are you referring to a segment / wire port or a edge port?

     

    For wires, there are segment ports and vertex ports. A segment port applies the voltage over the length of the segment that has the voltage source, while the vertex port applies the voltage between segments with a 'zero length gap'. In both cases FEKO does not add additional capacitance. The difference between the two will be dominated (when applicable) by the difference in phase due to the difference in the voltage source position (difference in the length of the gap).

     

    For edge ports (if you are modelling the antenna as a cylinder), no additional capacitance is added either and the voltage source is applied on the boundary of the two faces.

     

    If you have more questions, please add some pictures or models so that we can better understand what you are referring to with your question.

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