RFID passive tag (or transponder) is a primary component of RFID system. Generally they are placed on the objects to identify, and thanks to the electromagnetic field generated by the controller, they are “activated” sending their chip memory information. A RFID tag, in fact, is composed by 3 parts:
AN ANTENNA that allows the propagation of the electromagnetic field
A CONDENSER that works as a battery: when the antenna receives the signal of the electromagnetic field generated by the controller, it charges producing the needed energy to send the information there are in the chip through the antenna.
A CHIP che come detto è la parte che contiene le informazioni circa l’oggetto al quale è posto.
Depending on the frequency, needs of memory and application needs, nowadays we have many kinf of transponders. With this section our purpose is to underline the main chips that are used in RFID sector.The link below is a summary diagram with tha main features of each tag.
Below again we divided single chip for its frequencies with the links of single technical datasheet.