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RF wave propagation losses inside a block with different environments (materials)
Posted Jun 14, 2012, 11:47 a.m. EDT Low-Frequency Electromagnetics, RF & Microwave Engineering 3 Replies
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Hi all,
I’m new using comsol and i need help to create a model.
My idea is simulate the electromagnetic propagation of RF waves (868 MHz) and view the propagation loss (dB/m). I want to simulate that propagation inside a cylindrical block, with boundary walls connected to ground. I have two different subdomains inside the block, and I want see the propagation changing the levels of both materials inside the cylinder, in different simulations.
My question is what model should I use (RF or another module), and how fix the source of signal and view the electromagnetic propagation or field level in different points of the cylinder. My final objective is determining the propagation of the waves between these two materials inside the cylinder. See signal loss as a function of distance.
Please, I would be so grateful if somebody could help me.
Thanks in advance.
Francis
I’m new using comsol and i need help to create a model.
My idea is simulate the electromagnetic propagation of RF waves (868 MHz) and view the propagation loss (dB/m). I want to simulate that propagation inside a cylindrical block, with boundary walls connected to ground. I have two different subdomains inside the block, and I want see the propagation changing the levels of both materials inside the cylinder, in different simulations.
My question is what model should I use (RF or another module), and how fix the source of signal and view the electromagnetic propagation or field level in different points of the cylinder. My final objective is determining the propagation of the waves between these two materials inside the cylinder. See signal loss as a function of distance.
Please, I would be so grateful if somebody could help me.
Thanks in advance.
Francis
3 Replies Last Post Jun 19, 2012, 4:15 p.m. EDT
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Posted:
1 decade ago
Hi
at 886 MHz the wavelength in air is some c_const/886[MHz] or some 0.34 m, so if your volume is about a meter across or more you are at the begining of the RF domain (wavelength small compared to the model size). If the domains are slightly or well below the meter length you are in the "grey zone" in betwen good validity of RF and of ACDC (long wavelength compared to model and feature sizes). Stil l would choose RF.
Then for the field calculations, take a look a the RF model in the model library and on the main web site, you will find most responses discussed therein
--
Good luck
Ivar
at 886 MHz the wavelength in air is some c_const/886[MHz] or some 0.34 m, so if your volume is about a meter across or more you are at the begining of the RF domain (wavelength small compared to the model size). If the domains are slightly or well below the meter length you are in the "grey zone" in betwen good validity of RF and of ACDC (long wavelength compared to model and feature sizes). Stil l would choose RF.
Then for the field calculations, take a look a the RF model in the model library and on the main web site, you will find most responses discussed therein
--
Good luck
Ivar
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Posted:
1 decade ago
Hi Ivar,
First, thanks for your help. My model represents a Silo of 20m height, and 10m diameter.
As you said, I am using the RF module because the wavelength is smallest than the cylinder dimensions (868MHz).
I have fixed the different subdomain properties of both blocks (together they form one), simulating air and wheat. The walls of the blocks are theorically connected to ground.
My idea was create a source of electrical field (a signal) in a point inside the block. And simulate the propagation losses of this electrical field across both different materials, and then view the plot graphics.
I'm using Comsol 3.4. I have searched in forums and discussions and I have not found anything like my model. Also I have searched in the model Exchange section and I didn't found a solution.
It's feasible the way I am proposing? If is not possible, what is the way to see these propagation losses across both materials?
Please, could you show me a similar model or give me a way to find a solution?.
Thank you so much
Francis
First, thanks for your help. My model represents a Silo of 20m height, and 10m diameter.
As you said, I am using the RF module because the wavelength is smallest than the cylinder dimensions (868MHz).
I have fixed the different subdomain properties of both blocks (together they form one), simulating air and wheat. The walls of the blocks are theorically connected to ground.
My idea was create a source of electrical field (a signal) in a point inside the block. And simulate the propagation losses of this electrical field across both different materials, and then view the plot graphics.
I'm using Comsol 3.4. I have searched in forums and discussions and I have not found anything like my model. Also I have searched in the model Exchange section and I didn't found a solution.
It's feasible the way I am proposing? If is not possible, what is the way to see these propagation losses across both materials?
Please, could you show me a similar model or give me a way to find a solution?.
Thank you so much
Francis
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Posted:
1 decade ago
Hi
Sorry but 3.4 is really "old" for me, anyhow I did neither not do much in RF at that time, and nothing really in that direction either.
From what you explain, I believe that is feasible, if you have the material properties and the geometry it's should not be different from any other RF or optics propagation. Unfortunately I really do not remeber even how it was to set up a source point in 3.4, and I do not have 3.5 running etiher.
But there must be more v3 users out there, that was a stable version at that time, and eveyone out here cannot always run after the last version ;)
--
Good luck
Ivar
Sorry but 3.4 is really "old" for me, anyhow I did neither not do much in RF at that time, and nothing really in that direction either.
From what you explain, I believe that is feasible, if you have the material properties and the geometry it's should not be different from any other RF or optics propagation. Unfortunately I really do not remeber even how it was to set up a source point in 3.4, and I do not have 3.5 running etiher.
But there must be more v3 users out there, that was a stable version at that time, and eveyone out here cannot always run after the last version ;)
--
Good luck
Ivar