eDisignSuite inductance simulation

[DAghi.1]

Hello,

I want to disign my own antenna for the ST25DV product. I follow the AN2972 and the AN5605 but when I use the eDisignSuite, the value of the inductance is not the same with my simulation with the software Advanced Disign System. Can you help me ?

[Henry Crane]

Hello,

can you tell us more about the antenna design you try to design? is it a single or double layer antenna?

Please share also your findings with us so that we help to go further into an explanation.

Best Regards,

Henry Crane, NFC/RFID support team

[DAghi.1]

Hello, thank you for your reply,

it is a double layer antenna. To be able to have the right resonance frequency, you must always add an adjustment capacity with the antenna, I think that in your software you have taken this into account by making an approximation of the parasitic capacity.

That's right ?

cordially

[DAghi.1]

I have another question, the inputs and outputs AC0 and AC1 of the ST25SV component are the antenna connections. Which one is the ground?

thank you in advance for your help

[Henry Crane]

Hello

first, sorry for this very late answers:

parasitic capacitance approximated in eDesignSuite corresponds to the intrinsic capacitor caused by the spacing between spiral wires. It is a parameter of the antenna equivalent model that causes the antenna to have a self resonant frequency, that is a frequency were impedance changes from inductive to capacitive.

Additional tuning capacitance that could be necessary to reach the right tag tuning frequency when the antenna impedance is not right is not part of eDesignSuite calculation.

AC0 and AC1 pins are Differential RF inputs. For all our products , AC0 and AC1 shall be connected to the antenna coil, with no low impedance path to Vss pin (ground pin) if any.

Best regards,

Henry Crane NFC/RFID support team