RFID reader with passive tags to read up to 1 meter

Hi!

I have a project where I need read rfid passive tags up to 1 meter. I have a robot and robot have to move in a wide area where exists random flags. That flags have rfid passive tags and when the robot is about 1 meter from flags then it must read rfid.

Which rfid reader for Arduino must I use? I have rc522 reader working on 13.56Mhz, but their radius is about 2cm (with 48db).

Thanks!

That sort of range is pushing it. You can get a UHF RFID readers that have much larger ranges but they are expensive.
UHF RFID

That is a huge problem, I need some cheaper for this project... Is there some techonology with pasive tags can i use to read up to 1 meter?

That you can buy no.

If you want to make your own oversize antenna then you could get that far, but that is a skill set above my pay grade and I suspect yours.