I have someone else's design that I have been asked to choose matching components for.
The antenna is a chip antenna and the filter is a band pass SAW filter in a single package. The SAW filter is a DC short to ground, so at DC, all the components are tied to ground, but at it's operating frequency, it acts like a proper transmission line network.
My question is, since this is on a PCB and I've got an Agilent/HP 8753 VNA with S11 only, what is the proper way to measure and select matching components for this?
More specifically, I have read from some App notes from TI that the way to calibrate the 8753 is to do OPEN, SHORT, and LOAD measurements on the actual board itself...But, what do you remove from the board to test the load? Where should the VNA measurement point be? Do I have to do each filter separately? Can I leave the SAW filter in or should I replace it with a 0ohm resistor?
I've made some component changes (namely only using L1, L2 and C2) and have got a reasonable match by measuring at the L1,C2,BPFilter node and ground (~-27dB@fo), but my range of my antenna is still spotty. I'm not sure what to compare it to or if I'm doing this measurement right.