Characteristic Impedance vs Input Impedance of a patch

Laides and Gentelmen of edaboard;

What is the dşfference of Characteristic Impedance and Input Impedance of a patch. I am designing a patch antenna, and to design its feeding geometry ı need to model a lambda/4 feed line between the patch and 50 ohm line.
So while I calculating the lambda/4 feed line width, I use chracteristic imp of the patch. Zf: sqrt (Za+50) formula.

But I dont understand characteristic imp and input impedance differance. input imp has imaginer part but characteristic imp does not. Can you explain me from a designer point of view please ?

characteristic impendance is impedance of the TL. input and output impedance is impedance at input port/output port, looking into TL.

As you will see, ı will calculate the lambda/4 feed line impedance with this generale formula;
Zline=sqrt(Zpatch*50)

So for Zpatch, it is written that characteristic impedance of the patch. Not the input impedance. I mixed up here. I can directly put a port and voltage source at the edge of the patch without feed lines and find the input impedance with an EM simulator. So ı should think the patch as a transmission line ?

You should think the patch as a load with impedance Zpatch and match it with the lambda/4 line. Your reasoning is right, you calculate Zline = sqrt(Zpatch*50) and design a line with a width that corresponds to that impedance, and you will see that the matching will occur.

your patch is not TL. your 50ohm line is TL. the characteristic impedance is belongs to 50ohm line..