QVCO test buffer match

I designed a QVCO, the frequency is 4G,now I need a test buffer to evaluate it
Does the test buffer need to match 50Ω? I know the test buffer for LNA must match 50Ω?I think the QVCO test buffer need not,but I am not sure.
Does the buffer that does not match 50Ω affect the phase noise and other performances?

The buffer is not affecting too much the Phase Noise but its linearity is important to don?t distort the signal.
In general the input impedance of the buffer is high and the output impedance is 50 ohms.

thanks vfone for your answer