How to analyze plane wave excitation on a passive unit cell

Hi,

I want to analyze a unit cell which is made of a substrate with a metal patch on the top surface and ground plane on the bottom surface. Such a unit cell can also be called as reflect array unit cell design. The unique property of such a design is that it does not have any feed or exciter. If I could design a patch using pcbstack and then delete the feed, that will be equivalent to my desired design.

I want to incident plane wave excitation on the unit cell and analyze its scattering characteristics.

I want to state one example given in the help center which is similar to my problem but it gives an error. Please see the code below.

f = 1e9;
ant = design(cavity,f);
figure
show(ant)

%%
ant.Exciter = []

ant = 
  cavity with properties:

            Exciter: []
          Substrate: [1×1 dielectric]
             Length: 0.1690
              Width: 0.1690
             Height: 0.0634
            Spacing: 0.0634
    EnableProbeFeed: 0
          Conductor: [1×1 metal]
               Tilt: 0
           TiltAxis: [1 0 0]
               Load: [1×1 lumpedElement]

When I use this line of code "ant.Exciter = [ ]" it gives an error. See Error message below.

Error Message:

Index exceeds the number of array elements. Index must not exceed 0.

Error in em.MeshGeometry/checkObjectClass

Error in em.BackingStructure/set.Exciter (line 85)

checkObjectClass(obj,propVal)

figure
show(ant)

Similar to the above figure, If I could delete the exciter or the feed from the designed antenna, that would serve my purpose.

Kindly please let me know the way out.

I am using MATLAB R2022b.

Answer 1

[Amish]

I understand that you are trying to analyse a unit cell which is made of a substrate with a metal patch on the top surface and ground plane on the bottom surface. But the property of this specific cell that it does not have any feed or exciter. Therefore, in order to simulate this particular design you want to have the exciter, set to empty.

The issue with this is that your version of MATLAB i.e., 2022b does not support this. However, it is possible to do this in the latest 2023a version as the feature "cavity structure without an exciter as an element of planeWaveExcitation environment" was released in 2023a.

Please find the relevant documentation links below for your reference:

Release notes for 2023a : https://www.mathworks.com/help/antenna/release-notes.html

The cavity page documentation for 2022b: https://se.mathworks.com/help/releases/R2022b/antenna/ref/cavity.html

[Biplob]

I have installed MATLAB 2023a. It works fine when I delete the excitation for a cavity antenna.

But how do I achieve the same with pcb stack. I want to delete the feed from the pcb stack.

Thanks in advance.