I just finished the PCB antenna design and then I will measure the S11 and VSWR from VNA. Before the measurement, I would like to make sure if my understanding about matching network is right or not.
The first step is to measure the s11( input impedance) of antenna itself.
The second step is to match it to be 50 ohm. I could add the matching network before the antenna to set to 50 ohm or I could cut the copper tape on antenna to set to 50 ohm. I guess the later is better.
It will be matched z1* to 50 ohm.
The next step is measure the output impedance(or s parameter) of RF chip. We want it to be 50 ohm. But, I won’t be…
So, I will add another matching network to match z3* to z2*( 50 ohm)
U.FL( red square in the attached file) will be placed to measure the s11 value. Smith chart will be used for matching too.
You might get better and faster responses at a forum focused on electronics or even better rf design in general instead of one focused on a design program. Might i suggest one of the following?
So you install UFL only to be able to connect the VNA?
I do it slightly other way: I do design the PCB with footprints series/shunt/series/shunt for matching network, couple it with series cap in the 50R plane. When doing the matching, i do remove the coupling cap, solder the short coax with VNA calibrated on its end, and measure S11 towards antenna (initially with series 0R populated and no caps). The same towards the RF chip. Having this, I can calculate matching networks, install them and measure again for verification. If I get the results expected, just put the coupling series cap - job done.
