According to the 2450AT43A100 Datasheet the area around the antenna needs to be free of ground plane (or other conductors) for a distance of about 5mm.
Also the antennas seem to be orientation dependant with a feed end and a radiating end.
The following advice is for the traditional square patch antennas and can be glossed over when looking at these LTCC mini antennas.
First I would look at pictures of other peoples implementations to get a feel. Then I would read the datasheet for the ceramic patch in question carefully and see if they have a reference layout, if the datasheet is a translation you may not be able to take all text advice literally, mistranslations do occur.
All the implementations I have seen have the patch mounted on a ground plane. It may be soldered, glued or stuck with double sided tape as required. The ground plane is usually on the top side of the PCB as this will give more predictable results than assuming it has to be behind a unknown pcb substrate dielectric. It is possible that the antenna is not supposed to make electrical contact with the ground plane for some reason, I think this unlikely but would not rule it out, in this case a tape or soldermask may be the correct remedy.
It is true that you should not have other unspecified ground below or next to the antenna or even dielectric materials adjacent or above the antenna unless specified in the datasheet, these may cause the antenna centre frequency to shift and cause problems with sensitivity.
You should not need to supply power to a passive patch and the power pins should probably be left floating so an antenna short detector is not triggered. There may be a current controlled antenna detector in some implementations and this will need to be turned off or a load resistor placed on the Vcc-RF pin.