How do I create a pcb stack with out any feed?

Hello,

I want to create a unit cell which has three layers, bottom layer(ground plane), middle layer(dieletric), top layer(patch). I am using pcb stack function to create it. But pcb stack funtion also needs feed location, feed diameter information. I want to design a passive unit cell with out any feed and incident plane wave and see its scattering characteristics. How do I delete the feed information from the pcb stack.

I have tried passing empty(NULL) to feed diameter and feed location object. But it gives error.

I am using MATLAB 2023a.

Thanks.

Biplob Biswas

PhD Research Scholar

Answer 1

[Rohit Kulkarni]

Hi Biplob,

In my understanding you are trying to create a “pcbStack” object in MATLAB without any feed.

The “FeedLocations” property of the “pcbStack" object is required and cannot be empty. However, you may be able to create a passive unit cell by setting the “FeedDiameter” property to a very small value, such as 1e-6, and then using the “sparameters” function to calculate the scattering parameters of the PCB stack.

Please refer to the documentations provided below for more information on “pcbstack” and ‘sparameter’.

pcbstack: https://in.mathworks.com/help/antenna/ref/pcbstack.html

sparameter: https://in.mathworks.com/help/rfpcb/ref/sparameters.html

Hope this helps!

[Biplob]

Hi Rohit,

Thank you for your answer.

Here are some of the observations made by me after making the feed diameter to 1 micro-meter.

I have tried simulating a unit cell design in both MATLAB and in a standard EM-simulator.

Since the EM simulator allows us to design without the feed. So, I have checked it for both with and without the feed configuration.

Observations:

1. Without feed in EM silumator which will be the actual design after fabrication shows no reflection within the range 6 to 7 GHZ. Whereas in MATLAB it is showing good reflection (-19 dB at 6.6 GHz)
2. With the feed in EM simulator, a shift in the resonant frequency is observed (-12 dB at 6.9 GHz)
3. Also I would like to take your attention to the point that, in EM simulator we can see both reflection and transmission characteristics. But in MATLAB the sparameter results show just the s11 plot. Is there any way where we can plot the transmission characteristics also.

Thanks & Regards,

Biplob