RFID magnetic antenna
I need help in simulation a magnetic loop antenna (13,6 Mhz). What software is capable of doing it nicely. I used only 4NEC2 but it seems this software have problems with simulating shapes with lenght << lenght of wave.
Any suggestions what software use?
Hello,
I would suggest you to read par 3.7 and further of "recent advances to NEC applications and validation" (you can download it free from the web). With double precision version (NEC2D) you can go further down in segment length. There are limitations with loops. When working on a long-range antenna, it should be possible to get reasonable results when you observe modelling guidelines.
I don't know what you would like to simulate (near field, field at certain distance for EMC, reactance, etc) and what type of antenna (wire loop, copper tape loop, etc).
If you have a very small loop, you may simulate at a higher frequency if you are interested in field very close to the loop.
If your antenna is planar and you are interested in impedance of the loop, you may tray sonnet lite (free version, I don't have experience with it).
Hello,
I tried ANSOF and it works Ok for very small wire antennas. I've simulated an RLC circuit (around 1 cm in size) at only 50 Hz and the software still computes the tiny radiation from the circuit.
Apart from the question, if common EM solvers will give correct results for 13.56 MHz RFID antennas, it should be clear, that they can be perfectly calculated by pure magnetostatic analyzers, e.g. FastHenry from fastfieldsolvers.com.
Hello,
You speak about "radiation from the circuit". Do you mean the near H-field or real radiation field (far field at let say 10m distance). What will be the size of the actual antenna and the expected total wire/trace length?
Hello,
Yes, I mean far-field radiation from the circuit. Also, near the circuit there are near H and E fields, which are quasi-static fields. I have calculated both near- and far-fields for the circuit. The circuit total length is around 10 cm.
About static-field simulation software, I agree it is convenient in some cases, however, I was interested in analysing the circuit fields as a function of frequency, from very low to very high ones.
It's clear, that coupling between H and E-field exists also for a 13.56 MHz antenna. Practically, the effect can be ignored for all RFID related calculations, including EMI regulation compliance. I tried to answer the original question about suitable analysis software.
kekosat300: The SW you used, is that NEC based? I can't derive that from their website.
I don't know, but it seems it is not a NEC code.