Measurement of the phase of the receiving waves with VNA 8753ES

[rizwan183]

Hi!
I want to measure the phase and amplitude of receiving waves with a horn or dipole antenna using VNA. Can someone suggest how can i do it? I am new to measurement. Thanks

 

[FvM]

You need to use two antennas, preferably in an anechoic chamber.

 

[rizwan183]

I have measured S21 and their was option to measure real and imaginary values from which i calculated phase which seems not quite right as phase response varied alot on single point with minor frequency difference i don't understand. Experimental setup and a sample measurement data is attached in pics.

 

[FvM]

You have to specify port extension to compensate for the total cable + air propagation delay, thought you know.

 

[rizwan183]

IF we need relative phase at different sample points still we need to compensate for these parameters.Also why the phase response obtained as shown in picture varied alot. It is supposed to be single angle.

 

[ferdem]

The coupling between the antennas(-80,-90,-100 dB...) looks too low to make a good phase measurement. Phase measurement is sensitive to power levels. You should provide high enough power to make a clear phase measurement.
It seems that you make a mistake in your measurement.
Check your antennas, their frequency band, polarization etc. Start with better coupled networks, you can make the same measurement using a coaxial cable over a frequency band.
Place an attenuator and see how phase measurement is affected if you want. Increase the test power and reevaluate the phase measurement.