I'm working on project but I'm not a technical guy, so I need your help badly if possible

in short , I'm looking for an RFID reader module that can be fixed on a small drone (quadcopter), it should work on battery and should be lightweight (maybe less than 0.5 kg).
it will read a passive 870mhz tag from at least 3 meters height.
there will be many other tags on the ground like every 2 meters, so the reader should read within 2 meters width range in order not to pick the other tags.
what module (specific model) should I use and also what antenna?
your help is much much appreciated !