Vendors by technology

Low Frequency (125-134 kHz) │ High Frequency (13.56 MHz) │ UHF USA (915 MHz) │ UHF Europe (868 MHz) │ UHF Japan (925 MHz) │ Microwave (2.45 GHz) │ Passive (without battery) │ Semi-active │ Active (battery powered) │ Combined with sensors

Passive (without battery)