FEKO simulations of an antenna buried in soil

Gracjan Kochanowski-Ossowski

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.

Jaehoon

Hello Gracjan,

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

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

Regards,

Jaehoon

Gracjan Kochanowski-Ossowski

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.

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).

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.