NFC Antenna Tuning using calibration coil

[hengma]

Hi,

I have a question related to the antenna tuning process of RFID readers using CLRC663. I noticed that all application notes use VNA to measure the impedance at the Tx ports of the chipset. May I know if there is an indirect way to tune the antenna? For example, can we place a calibration coil on the reader and measure the voltage from the calibration coil? A high-impedance probe is used to measure the voltage from the calibration coil. The antenna is tuned using a variable capacitor and is considered to be well-tuned once the maximum voltage from the calibration coil is obtained. May I know if it is feasible?

Thanks,

Heng

[KaiLi · Accepted solution]

Hello @hengma 

Thanks for contacting us and using the NXP products.

Your approach sounds feasible, but NXP has no such precedent, so it is difficult to give you relevant advice. It is still recommended that you use the method recommended by NXP to achieve it.

BR

kelly

[hengma]

Thanks for that. Understood.