Hi
I am working on a University project where we need to impliment 24 of the same Mini RFID-RC522 onto a single PCB. Instead of buying the full reader 24 times per PCB and using the PCB only as a connection board to an ESP32 (as we have done so far), we want to build the full reader (incl. antenna) onto the PCB directly. My issue is now that I cant find the full EMC Filter & Matching Circuits for (example) this Reader in the schematics provided with the product online (its missing 2 caps and a couple of resistors and the LED, the issue is only the caps with the antenna).
Also we don't have access to the equipment to build and then determine the antenna characteristics on our own as would have been outlined how to do in this document.
If it helps in any capacity, size of the antenna is:
outer lenght: 30mm
inner lenght: 24.5mm
outer width: 24mm
inner width: 18mm
Any help would be greatly appriciated.
PS: Attached I have a drawn version of cap locations on the MINI RFID-RC522, here the same highlight of the cap corresponds to same capacitance of the cap, but measurements dont reflect values found in the schematic found above (factor +-1.5-2), therefore I left them out (capacitor measurement has been done using a frequency generator and high ohm resistors looking at their chargecurve on a oscilloscope). The cap names are derived from this version of the product
Correction, the resistors R4 and R5 are not shorted, and their inner (left) pads are connected to the antenna. The outer pads are connected either up/down to the caps (R4 is connected to C9, C11, C15 and R5 is connected to C13, C14, C16)
