FEKO simulations of an antenna buried in soil

Gracjan Kochanowski-Ossowski
Gracjan Kochanowski-Ossowski Altair Community Member
edited April 2 in Community Q&A

Hello,

I am working on simulations of antenna buried at depth 1m in ground. I would like to perform couple of simulations including different soils (sand, dirt, higher water content etc.).

  • Is there any example of a similar problem?
  • What would you recommend to decrease the simulation time (even  simple PEC suboid of 2x2x2 with planar antenna inside was simulating whole day unless i made a mistake)?
  • Do i just need to place the antenna inside a soil model and start simulations or do i need to follow certain steps to do so?

I am fairly new to FEKO and that kind of simulations, thanks in advance for your time.

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Answers

  • Jaehoon
    Jaehoon
    Altair Employee
    edited April 2

    Hello Gracjan,

    I would recommend you to use "Homogeneous Half Space in Region Z<0 (Exact Sommerfeld Integrals) to implement a soil.

    image

    image

    The antenna can be simply positioned inside this half space. I mean "below Z".

    Regards,

    Jaehoon

  • Gracjan Kochanowski-Ossowski
    Gracjan Kochanowski-Ossowski Altair Community Member
    edited April 2
    Jaehoon Kim_22316 said:

    Hello Gracjan,

    I would recommend you to use "Homogeneous Half Space in Region Z<0 (Exact Sommerfeld Integrals) to implement a soil.

    image

    image

    The antenna can be simply positioned inside this half space. I mean "below Z".

    Regards,

    Jaehoon

    Thank you so much for your reply,
    In my version of feko i do not see Soil in the library of mediums, is it just for example or is there any particular model of soil in other versions? For first simulation I took frequency independent material, Relative permittivity of 10, Conducitivity 0.001 S/m, and loss tangent 0.3.


    Couple of specifics about frequency and antenna:
    In the long run im going to simulate the transmission between LoRa Gateway ( above ground) and LoRa sensor (buried in ground 1 meter depth). Frequency is 868MHz.

    First iteration consist a patch antenna from FEKO and infinite ground plane as you suggested, i calculted single frequency point and compared it to the S11 reference, there's decrease of RL by 20dB (-3.95 dB S11 compared to -25dB without soil plane).

    image

    I wanted to ask about some hints in terms of specify the soil model, should stick to Homogeneous Half Space in Region Z<0 and modify the electric parameters, or try to implement 3D model of soil with some layers? I fear that this manoeuvre will take a lot of time to simulate.

    Also, any recomendations about the casing of the antenna? Since it is buried beneath the ground i should  cover it up with ABS plastic?

    I will keep updating the thread along with the progress.

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