I want to design microstrip antenna for UHF RFID. The chip I'm using is SL3S1013FTB0. I found some demo kits and found some antenna examples. One of them has small antenna that I'm especially interested in and it looks like this:

reference design

But there is no information about this design and to be honest I'm having a hard time understaing how it works. What is more, when I checked the gerbers it seems to be shorted to ground!

small antenna

Can anyone explain how it works or recommend any book/article that explains it?

  • \$\begingroup\$ This is what we in the trade commonly call "RF magic". It relies entirely on the parasitic elements that you normally ignore as unimportant, but which become significant as you increase the frequency. \$\endgroup\$ – Hearth Jan 26 at 20:55
  • \$\begingroup\$ @Hearth Ok, but where is matching network and how it radiates? Input impedance of this chip is 25-j237, so it is highly capacitive. Don't we need to match it with inductance? I think this meandred trace is not meant to be inductor. You can find full PCB here p. 14 \$\endgroup\$ – KRol Jan 26 at 21:17
  • \$\begingroup\$ @Hearth As far as I understand matching network is essential to efficiently collect power from reader signal. So if the IC have 25-j237 impedance antenna should have conjugate match of the chip impedance, that is 25+j237. \$\endgroup\$ – KRol Jan 26 at 21:47

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.