I am into RF design and I have some queries related to impedance matching and trace. We had an RF module and the module was connected to an antenna through a single trace with no LC components in between for additional matching. But the trace width was set such that its characteristic impedance was set to 50 ohm. But in real time testing it was seen that the antenna feed impedance when measured from the RF module it was only 19 ohm, and after additional tuning I could achieve only up to 40 ohm.
Even thought the RF trace impedance was set to 50 ohm why did the impedance vary?
So is there any way in which the impedance can be improved by varying the RF trace impedance alone such that we can improve the 19 ohm to a value such that after additional tuning we can make it 50 ohm.
Also if we can set the trace impedance to the characteristic impedance why do we do we provide additional LC tuning and how is the matching done using the LC tuning?