Ground plane, patch, feedline dimesnion and the impedance matching

[peteryuan]

I am design a micro strip patch antenna for UWB application (3.1-10.6GHz) in CST.
The substrate is Rogers RT 5880 and the feedline, patch and ground plane is Copper (Annealed).
The feedline is Micro Line Feed.

the is result for S-parameter is accepted but the z-matrix(impedance) is around 40ohms

but my minimum tolerance is at least 0.5mm and the impedance is 50 ohms.

How & what is the dimension of the thickness of the patch, feed line and ground plane for that specification as mention above?

What other improvement can be made?

 

[diligence]

Hi,

I suggest the following:

To have a realistic thickness for your patch, feed line & gnd plane, consider 1 oz of copper (~1,4 mils or 0.034 mm approximately). These numbers depend upon what thickness do you specify to the PCB manufacturer while manufacturing this design. I usually use 1 oz of copper in my pcb designs.

I am not sure on this end, but you can make the ground spread out on the complete board dimension on the bottom layer. Currently I see you have it only below the feed line. Also I think you can consider the feed line as a microstrip and use any of the online microstrip calculators to decide upon the feed line's width to match the 50 ohm impedance of your patch.

I hope this helps to improve your design.

 

[peteryuan]

https://obrazki.elektroda.pl/2290179600_1437454288.jpg

when using cst the result is 40ohms but the calculator give 35ohms

 

[peteryuan]

the white is the substrate which is between the feed and the ground.
they all are just above the substrate.

the result from cst and the microstrip calcluator