TC4308I-112J TOKEN [Token Electronics Industry Co., Ltd.], TC4308I-112J Datasheet - Page 3

• Manufacturer Part Number: TC4308I-112J
• Description: Chip RFID Transponder Coils
• Manufacturer: TOKEN [Token Electronics Industry Co., Ltd.]

Version 2010
Transponder Coils in an RFID Radio Frequency Identification System
RFID, Radio Frequency Identification, is the system of using radio signals to send information identifying a
particular item. The most common application of RFID is to track and locate any subject including material, or
moving item.
The RFID transponder coil is part of the coupling device and acts as the transmitting antenna. The main
specifications of the transponder coil are sensitivity and read distance, however, the inductance of the transponder
coil directly influences the sensitivity and the read distance. Generally, a higher inductance provides greater
sensitivity resulting in a longer read distance.
There are two major components in an RFID system:
The manufacturer of the tag usually specifies the inductance of the coil to be used. The read distance is defined
as the maximum distance from the reader that the transponder responds to the reader’s magnetic field. The reader
produces a magnetic field that triggers the tag. When the reader receives the transmitted data, it interprets the data
and takes appropriate action as shown in figure 1.
When the transponder enters the field produced by the reader, the coil produces a voltage inside the tag. In an
active transponder, the voltage is used to wake the tag and use its internal battery. In a passive transponder,
this voltage can be used to power the tag. Active transponders generally have longer read distances, shorter
operational life and are larger and more costly to manufacture. Passive transponders are generally smaller, have a
longer life and are less expensive to manufacture.
For optimum performance, the transponder coil is used in a parallel LC circuit as shown in figure 2. Adding
a capacitor to the circuit maximizes the read distance. The LC circuit is designed to resonate at the operating
frequency of the reader. To calculate the value of the capacitor, use the following
equation: Capacitance (C) = 1 / (Inductance L x (2π x Frequency ƒ))
Transponder Coils Applications
● Tag:
● Reader:
The transponder programmed with unique information. The tag consists of an integrated circuit
and a coupling device. The integrated circuit stores specific data unique to that tag.
The interrogator includes a decoder to interpret data. The coupling device interfaces with the
reader.
Reader
Magmetic field produced
Data transmitted
Figure 1. RFID System
by the tag
by the reader
TR4308I Chip RFID Transponder Coils
http://www.token.com.tw/
Tag
rfq token.com.tw
Figure 2. LC Circuit
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