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Patch Antenna Simulation Issue

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Hello

 

I am trying to simulate a patch antenna that consists from 2 patches and should work on 4.3 GHz center frequency. For some reasons The Y (V) antenna pattern cut is not symmetric. The X (U) cut is symmetric and VSWR value looks ok.

Attached the antenna design data.

I kindly request your assistance to find out the reason for this symmetry issue.

Thanks in advance. 

4.3 GHz Dual Patch Antenna.cfs

4.3 GHz Dual Patch Antenna.opt

4.3 GHz Dual Patch Antenna.pre

4.3 GHz Dual Patch Antenna.bof

4.3 GHz Dual Patch Antenna.out

4.3 GHz Dual Patch Antenna.str

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Hi sem

 

I don't see the model file attached. If you want others to take a look at the antenna design, please also your CADFEKO model file (.cfx).

 

Kind regards

Madelé

 

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Dear sem

 

Having taken a quick look at your model, I would expect there to be currents flowing on your feed lines and that these are also radiating.

 

This would then be expected to result in an unsymmetrical effect on your radiation pattern and specifically your VN cut.

 

Kind regards,

Johan H

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Hi sem,

 

For 100% symmetric results, the mesh needs to be symmetric. Keep in mind that not the geometry but the mesh is solved (currents on edges between adjacent triangles). Plus, when applying symmetry planes in CADFEKO you will drastically decrease runtime/memory.

image.png.6e99f778ffc2adce572cfca4314a52c8.png

In your model a magnetic symmetry plane can be applied (after simplifying), see 4.3 GHz Dual Patch Antenna_sym.cfx.

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Hello

 

I have fixed the edges and applied the symmetry.

The antenna radiation pattern on Y (V) plane is still non symmetric.

I attach the updated model and the radiation pattern picture.

What can be the source for this issue?

Many thanks for your support!

 

Radiation pattern.jpg

4.3 GHz Dual Patch Antenna.cfs

4.3 GHz Dual Patch Antenna.opt

4.3 GHz Dual Patch Antenna.pre

4.3 GHz Dual Patch Antenna.bof

4.3 GHz Dual Patch Antenna.out

4.3 GHz Dual Patch Antenna.str

4.3 GHz Dual Patch Antenna.fek

4.3 GHz Dual Patch Antenna.pfg

4.3 GHz Dual Patch Antenna.cfm

4.3 GHz Dual Patch Antenna.cfx

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Hi sem,

 

I'm not sure why you expect the ff_VN far field to be symmetric? The model is not symmetric to the VN plane, and as Johan Huysman already mentioned, the (strong) currents in the feed lines contribute to the far field radiation:

 

image.png.25472d0643566ec9edeb5602f9651a5a.png

 

You may specify which faces contribute to a far field by using Scope in the far field diaogue. Here, only the patches are taken into acount:

image.png.477575d77df058508c353a479d5025e8.png

 

Now the patterns are almost symmetric. Of course still the position of the feedlines disturbs.

image.thumb.png.caa98a14ef71f1974087eee3667f3f4f.png

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Hello

 

How should I add faces to the scope dialog that is described above?

There is no option there to type a face name or choose the relevant face.

Thanks.

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11 hours ago, sem said:

How should I add faces to the scope dialog that is described above?

Simply click in the field and then click on the face in the 3D view and the label of the face will be added.

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Hello

 

I have solved the symmetry issues stated above and have proceed with the design. Now I want to round the 4 substrate corners by the radius of 6.35 mm to better simulate the antenna.

How can I do that?

I attach the latest design.

Your assistance is highly appreciated.

Thanks in advance.

 

4.3 GHz Dual Patch Antenna.cfm

4.3 GHz Dual Patch Antenna.cfs

4.3 GHz Dual Patch Antenna.cfx

4.3 GHz Dual Patch Antenna.cfx.bak

4.3 GHz Dual Patch Antenna.fek

4.3 GHz Dual Patch Antenna.opt

4.3_GHz_Dual_Patch_Antenna.out

4.3 GHz Dual Patch Antenna.pfg

4.3 GHz Dual Patch Antenna.pre

4.3 GHz Dual Patch Antenna.str

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Hello

 

I have meant above that I want to round the substrate and not the patches. Nevertheless I have done it using CAD SW tool and then have imported it back (the substrate) to FEKO and redefined its parameters and it works.

Now I want to duplicate my antenna (have 2 identical antennas in same FEKO design) in order to calculate a coupling between them. Since the antenna substrate now is a primitive object, I have a difficulty  to move it.

How can I solve this issue?

Thanks.

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