Hi,
In application note 'nWP017 - Antenna tuning', it provides quite a lot information about how to tune antenna.
But, once it is properly tuned, how do I know the matching network is also proper for IC ?
I've got a VNA to tune the antenna matching network with calibration correction to the point where it is connected to IC.
But once the LC network is installed on the pcb between IC and antenna, how can I measure whether these two is still matched?
If I have a spectrum analyser or oscilloscope, once I place probe tip on the ANT pin of IC,
it will surely introduce an excessive input capacitance and change the output RF signal.
Obviously I can't add additional fixture for VNA to measure S11 any more.
So my question is how to tune matching network with both IC and antenna in place? Is there any kind of "chip VNA" available?
Best Regards,
Leo