From time to time, customers have asked how to make 360 degree phase measurement, for a vector network analyzer (VNA), using AD8302. Switchable phase delay and two AD8302 in quadrature configuration have been proposed. Is there a preferred method?
Here is a paper discussing this topic. An additional thought is to include a shunt switch with a cap to INPA to add, say, a degree of phase lag. This would allow a user to identify the polarity of the phase difference. Certainly one needs to be careful around the 0 and 180 degree points. There are customers that have implemented such an idea with success...
Thanks Jeritt, this is an excellent resource.
we have tried this method but we found problem in phase shifting of 90deg. The phase shifting has to be absolute but all of the devices are relative which is not helpful for me. The phase shifter we used in Mini circuits JSPQ series and the frequency range of operation is 3-30mhz.. My intention is to estimate antenna impedance and for that i need magnitude and aboslute phase 0 to 360 deg.Kindly help out.