How to know antenna is properly matched with IC ?

[wanyancan]

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

[wanyancan]

Current idea I have in mind is to insert a PA chipset in between IC and matching network. 

I can find a PA with power level indicator output. 

By setting the radio frequency at each channel from 2400 to 2480,

and let the 52832's ADC measuring the PA's power level indicator (analogue voltage output).

It probably is kind of scalar power meter. 

Please let me know how to do it more quickly or in a professional way without breaking the IC and antenna connection.