Dear fellows,
I am trying to design an antenna for near-field magnetic coupling (UHF RFID). I know that it is easy to design such an antenna in HF. A multi-turn loop works great. However, in UHF, we all know that it is quite different due to the radiation resistance, parasitic capacitance, and so on. Therefore, I have several questions on the transmitting antenna:
1) what kind of antenna is good for this application? Will the loop still do its job, or other potential shapes?
2) Theoritically, higher current will create a higher H field. Should we persue an antenna with lower resistance? We can match it to 50 ohm later. Here, I believe that we don't need to care much on the radiation resistance.
3) Is there an easy PCB-based balun that we can implement? So we can connect it with the coax cable and the loop.
Thank you for help.