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Radition pattern

Posted Oct 24, 2012, 8:28 a.m. EDT RF & Microwave Engineering Version 4.2a 4 Replies

Samuel Roj
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Dear Fellows,

I simulated dipole antenna and calculate the normalized electric field in the gap of the antenna (near field).

Now I want to plot the radiation pattern. Can you tell me where I can find formulas for that, or is there some option for that in Comsol, or maybe you can recommend me some RF module from model gallery?

Thanks in advanced.
4 Replies Last Post Oct 24, 2012, 12:42 p.m. EDT
Edgar Kaiser
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Posted: 1 decade ago Oct 24, 2012, 9:08 a.m. EDT
Hi,

the COMSOL RF module contains the far field calculations. You have to include a 'far field calculations' node into the model. This is available under the RF physics node. In the far field node you must define the boundary that serves as input for the far field calculations. This can be a sphere around your antenna, possibly the inner sphere of a PML.

This makes the far field variables available for post processing.
But take care: 3D far field post processing takes a lot of time, sometimes more than solving the model. If you restrict it to 2D, such as the typical polar azimuth and elevation diagrams you are fine, they are quick. Please note: the model can still be 3D, just the post processing should be 2D.

Cheers
Edgar
Hi, the COMSOL RF module contains the far field calculations. You have to include a 'far field calculations' node into the model. This is available under the RF physics node. In the far field node you must define the boundary that serves as input for the far field calculations. This can be a sphere around your antenna, possibly the inner sphere of a PML. This makes the far field variables available for post processing. But take care: 3D far field post processing takes a lot of time, sometimes more than solving the model. If you restrict it to 2D, such as the typical polar azimuth and elevation diagrams you are fine, they are quick. Please note: the model can still be 3D, just the post processing should be 2D. Cheers Edgar
Samuel Roj
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Posted: 1 decade ago Oct 24, 2012, 9:22 a.m. EDT

Hi,

the COMSOL RF module contains the far field calculations. You have to include a 'far field calculations' node into the model. This is available under the RF physics node. In the far field node you must define the boundary that serves as input for the far field calculations. This can be a sphere around your antenna, possibly the inner sphere of a PML.

This makes the far field variables available for post processing.
But take care: 3D far field post processing takes a lot of time, sometimes more than solving the model. If you restrict it to 2D, such as the typical polar azimuth and elevation diagrams you are fine, they are quick. Please note: the model can still be 3D, just the post processing should be 2D.

Cheers
Edgar


Thank you very much for your response. Yes, I need 2D plot.

Just to be clear, you say that if I want to plot radiation pattern I have to put Far Field domain BEFORE simulation?

But can you give me some advice with this. It is not so complicated to put all equations for far filed domain when I have antenna in air free space. But problem is my antenna is on substrate, so I am not sure how to make sphere on which I have to do far field calculations. Is it possible to make sphere which is one half in the air, one half in glass?

In any case thanks on first response.

Best regards
[QUOTE] Hi, the COMSOL RF module contains the far field calculations. You have to include a 'far field calculations' node into the model. This is available under the RF physics node. In the far field node you must define the boundary that serves as input for the far field calculations. This can be a sphere around your antenna, possibly the inner sphere of a PML. This makes the far field variables available for post processing. But take care: 3D far field post processing takes a lot of time, sometimes more than solving the model. If you restrict it to 2D, such as the typical polar azimuth and elevation diagrams you are fine, they are quick. Please note: the model can still be 3D, just the post processing should be 2D. Cheers Edgar [/QUOTE] Thank you very much for your response. Yes, I need 2D plot. Just to be clear, you say that if I want to plot radiation pattern I have to put Far Field domain BEFORE simulation? But can you give me some advice with this. It is not so complicated to put all equations for far filed domain when I have antenna in air free space. But problem is my antenna is on substrate, so I am not sure how to make sphere on which I have to do far field calculations. Is it possible to make sphere which is one half in the air, one half in glass? In any case thanks on first response. Best regards
Edgar Kaiser
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Posted: 1 decade ago Oct 24, 2012, 11:19 a.m. EDT
Yes, you must define the far field domain before running the model. Otherwise you don't get the variables.

Regarding the substrate, I must admit I don't know. I would expect the model will run with a hetrogeneous far field domain. You will need to check the results for plausibility with a simple case. Maybe the dipole is well suited for that.

Cheers
Edgar
Yes, you must define the far field domain before running the model. Otherwise you don't get the variables. Regarding the substrate, I must admit I don't know. I would expect the model will run with a hetrogeneous far field domain. You will need to check the results for plausibility with a simple case. Maybe the dipole is well suited for that. Cheers Edgar
Samuel Roj
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Posted: 1 decade ago Oct 24, 2012, 12:42 p.m. EDT
Thank you very much on answer.

Regards
Thank you very much on answer. Regards

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