Where to take PCB antenna measurements?

Hi, I am doing some measurement on a PCB antenna. May I know where should I place the antenna so that the measurement result will be more accurate?
On table? wood? plastic?.....etc or hanging freely on air? Thanks!

Best is to put the antenna in the final situation. so if the PCB will be used in a plastic case, you should test it in a plastic case as this may change reflection coefficient and radiation pattern. The complete unit with the antenna you can put on foam block (expanded polystyrene), or hang it in the air with rope.

Keep al metal away, have sufficient clearance from surfaces (floor, ceiling, walls, your own body, etc) and do the measurement again where you change the distance from measurement antenna to DUT. This is to assess the effect of far field issues and reflections from objects (walls, floor, etc).

Make sure that you have good common mode decoupling on the feed cable when you use an external generator to feed the antenna.