RFID distance transmitter
If you really want to use RFID, you will have the following possibilities to reach distances greater than 50 cm:


HF RFID at 13.56 MHz, particularly the tags based on the ISO 15693 standard (not NFC and ISO 14443 which operate on the same frequency), which do not have any security features and the reader has no need to feed the crypto chips within the tags. However, if you use inductive based RFID technologies, keep in mind that the reader antennas diameter has to be in the range of the distance to be bypassed. Some NFC controllers support also the ISO 15693 standard. If you get a reader, checkout for higher energy supply.
UHF RFID around 900 MHz (frequency depends where you use it): Distances up to 10 meters in free space are possible. The disadvantage is the high price due to the more sophisticated hardware.