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AN678
| Title |
Title
RFID Coil Design
|
|---|---|
| Name |
Name
AN678
|
| Date |
Date
06/24/2015
|
| Description |
Description
In a Radio Frequency Identification (RFID) application, an antenna coil is needed for two main reasons: ? To transmit the RF carrier signal to power up the tag ? To receive data signals from the tag An RF signal can be radiated effectively if the linear dimension of the antenna is comparable with the wavelength of the operating frequency. In an RFID application utilizing the VLF (100 kHz ? 500 kHz) band, the wavelength of the operating frequency is a few kilometers (l = 2.4 Km for 125 kHz signal). Because of its long wavelength, a true antenna can never be formed in a limited space of the device. Alternatively, a small loop antenna coil that is resonating at the frequency of the interest (i.e., 125 kHz) is used. This type of antenna utilizes near field magnetic induction coupling between transmitting and receiving antenna coils.
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