For radiation pattern measurement of antenna

I had a problem to measuring and understanding the problem to measuring of radiation pattern. How it colud be measured and test of simulation value range and require range for the dongle application.
E and H filde configuration along radiation pattern. It should be omni, uni or bi directional.

Antenna radation pattern measurement requires a test range (best an open area without obstacles), a reference antenna, a transmitter and a calibrated receiver.
Details can be found in antenna textbooks and you can google commercial companies offering such service.
The pattern is measured relative to a maximum directivity in dB, and antenna under test is orientedin small angular steps to obtain a point-to-point pattern. Similarly polarization response can be taken, then the reference antenna must be calibrated for pol/copol response.

Thaks to you,
And we observe polarization diversity on what basis in mimo antenna ?

On what basis polarization diversity woiuld be measured ? And how it could be measured in HFSS ?