I am getting right answers for Co-phase and wrong for anti-phase

Oluwaseun Falade
Oluwaseun Falade Altair Community Member
edited March 2022 in Community Q&A

4 antennas of 15 cm in length and of radius 1 mm separated in free space by 1.5 m. The center‐fed dipoles are conjugately matched at 1 GHz by connecting the load of 90.7 − j 42.7 Ω. They are also separated by the same distance of 5 wavelengths or 1.5 m. 1 watt power is also applied. The basic philosophy is that since there are two antennas each for the transmit and receive systems, one can communicate with two spatial orthogonal modes of the system. The two orthogonal modes of the excitation of the antennas will be of 1 V each fed to the transmitting antennas so that they operate in phase. The other orthogonal mode will have a +1 V and –1 V excitations to each of the transmitting antennas so that the excitations are orthogonal.

 

I was able to get close enough values for the first mode of 1 voltage, using the same method and reversing the polarity, my values for antiphase(1,-1) were wrong. This is what my project looks like:

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I decided to use this one below: still getting wrong answers. Please help

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Answers

  • Mel
    Mel Altair Community Member
    edited March 2022

    Some things that you could check:

    1. Check that the orientation of all the ports are the same. Red side is the positive side.
    2. You may need finer meshing on the wires in some cases. You could set the mesh size to Custom and maybe set the wire segment length to lambda/20.
    3. It may be that there is still a significant amount of mutual coupling that could make the impedances of the dipoles different, which would mean you would need to adjust the loading to make the model "symmetrical" again.

    Also just remember that the power setting is applied over all active sources so that the combined power is 1 W.

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