While going through the document at https://www.silabs.com/documents/public/application-notes/AN639.pdf I have read from "Figure 13. Loop Antenna Simulated Mag(Zin) vs. CP1" below that even a 2% tolerance for Cp1 results in a Zin of about 200 - 250 Ohm for the 434 MHz frequency range that I am heading for. The desired Zin is 500 Ohm.
I am not sure if this is the case but as I understand it this will cause a good fraction of the power to be reflected back into the IC. If so, could I have a maximum tolerance level for Cp1 so that my transmitter will not require full power in order to cover a mere few meters ? (in ohter words, for my transmitter not to perform poorly)