A Luneburg Lens fed by an aperture patch antenna

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Ly. 明亮
Posts: 5
Joined: Thu 03 Dec 2020, 05:56

A Luneburg Lens fed by an aperture patch antenna

Post by Ly. 明亮 » Thu 03 Dec 2020, 17:32

Hello everyone:

I am a new user of the openEMS. I want to simulate a luneburg lens fed by an aperture patch antenna. But In my simulation, I found that the wave from the patch didn't enter the luneburg lens, and the result of radiation pattern was the same with pattern of the aperture patch without the luneburg lens. I don't know what happened and where is the error.
Can you help me? Thank you very much!
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Lumber_patch_test5.rar
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Ly. 明亮
Posts: 5
Joined: Thu 03 Dec 2020, 05:56

Re: A Luneburg Lens fed by an aperture patch antenna

Post by Ly. 明亮 » Sun 06 Dec 2020, 17:19

Hello everyone:

I have found the reason why the pattern of the luneburg lens fed by an aperture antenna was the same as the aperture antenna's pattern without the lens in my project is that the function 'ImportSTL' in openEMS has some errors. It will transform the cavity structure into a solid structure. In my project, I constructed the luneburg lens with 10 sphere shells in the CST, and imported the ten STL files into my project with the 'ImportSTL' function, so the sphere shells were transformed into spheres. Because I set the ten structures the same priority, so the whole structures became a solid sphere whose relative permittivity was 1.05 and resulted in the fault pattern.
I get the correct result which agrees well with CST by remodeling the structure in openEMS instead of importing STL files. Thank you all for your attention。


Ly.bright

thorsten
Posts: 1438
Joined: Mon 27 Jun 2011, 12:26

Re: A Luneburg Lens fed by an aperture patch antenna

Post by thorsten » Sun 06 Dec 2020, 18:40

Hi,

good that you found the issue.

By the way, do you know that openEMS supports coordinate dependent definitions?
Maybe useful for your case?

See "help SetMaterialWeight", but from the example:

Code: Select all

     CSX = AddMaterial(CSX, 'material');
     CSX = SetMaterialProperty(CSX, 'material', 'Epsilon', 1);
     CSX = SetMaterialWeight(CSX, 'material', 'Epsilon', ['(sin(4*z / 1000 *2*pi)>0)+1']);
which defines a "wavy" epsilon material distribution...

regards
Thorsten

Ly. 明亮
Posts: 5
Joined: Thu 03 Dec 2020, 05:56

Re: A Luneburg Lens fed by an aperture patch antenna

Post by Ly. 明亮 » Wed 09 Dec 2020, 12:30

Hi Thorsten,

Thanks for your reply and suggestions, I will have a try. But now I want to consult you another question. My purpose is to create a hemisphere and rotate it 30° around the X axis, so I create the strcucture using the 'AddRotPoly' function and try to rotate it, but I find that the 'AddRotPoly' function can't to achieve the rotation. I only find that a structure can be rotated when created using the paramter 'Transform',{Rotate_x,30} such as
AddBox(CSX,'Material',start,stop,'Transform',{Rotate_x,30})
. So I want to consult you how to construct a rotatable hemisphere or how to rotate an existing structure in openEMS. Thanks for your attention and look forward to your reply.

regards
Ly.bright

thorsten
Posts: 1438
Joined: Mon 27 Jun 2011, 12:26

Re: A Luneburg Lens fed by an aperture patch antenna

Post by thorsten » Wed 09 Dec 2020, 23:20

Not sure if this is your question, but you can append this transforms to any primitive in openEMS (not only a box).
Additionally you can use the priority concept to define a sphere and use a box to cut off half of it by using a higher priority and an "air" material.
And by rotating the box you can cutoff any part.

regards
Thorsten

Ly. 明亮
Posts: 5
Joined: Thu 03 Dec 2020, 05:56

Re: A Luneburg Lens fed by an aperture patch antenna

Post by Ly. 明亮 » Sat 27 Mar 2021, 06:57

Hi Thorsten,

Thanks for your reply and suggestions. Now I'd like to consult you another quenstion. I am confused about the results of post-processing functions that are ' plotFFdB() ' and ' plotFF3D ' . Which of the following indicators: ' Gain, Directivity, Far Field ' does the y-axis of the figure represent? I want to get the Gain.

regards
Ly.bright

thorsten
Posts: 1438
Joined: Mon 27 Jun 2011, 12:26

Re: A Luneburg Lens fed by an aperture patch antenna

Post by thorsten » Wed 31 Mar 2021, 21:44

I think these functions just plot what you feed in. Have a look at some of the antenna tutorials for more details and examples.

regards
Thorsten

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