RFID system using circular polarized antenna
The present disclosure relates to an RFID (Radio frequency identification) system using circular polarized antennas, wherein a reader emits electromagnetic wave through reader antennas to recognize a tag and to read out customer information if a customer proximity is detected, where the reader antennas are installed at a kiosk body and at a rear proximity position of a floor surface on which a customer using the kiosk stands, and the reader antennas installed at the rear proximity position of the floor surface emits circular polarizing wave toward the kiosk, whereby the tag can be accurately recognized regardless of position of the tag of the customer.
1. An RFID (Radio frequency identification) system using circular polarized antennas, the RFID system comprising:
a proximity sensor mounted at a kiosk and configured to sense proximity of a customer to the kiosk;
a customer detector configured to detect whether the customer has proximately approached the kiosk by using a sensing signal from the proximity sensor;
a server configured to request customer information and provide the customer with services based on the customer information if the customer detector detects that the customer has proximately approached the kiosk; and
a reader configured to:
recognize a tag by emitting an electromagnetic wave through a plurality of reader antennas when the server requests the customer information;
read the customer information stored in the recognized tag; and
provide the customer information to the server,
wherein the plurality of reader antennas comprises:
a first reader antenna mounted on an upper portion of a body of the kiosk
a second reader antenna mounted at a middle portion of the body of the kiosk; and
a third reader antenna mounted at a rear proximity position of a floor surface on which the customer stands.
2. The system of claim 1 , wherein the third reader antenna is configured to emit the electromagnetic wave toward the body of the kiosk at an angle.
3. The system of claim 2 , wherein the angle is within a range of 10°˜30° with respect to a perpendicular line.
4. The system of claim 1 , wherein:
the third reader antenna is formed with a plurality of circular polarized antennas of a 2×2 array; and
a first of the plurality of circular polarized antennas arranged near the kiosk and a second of the plurality of circular polarized antennas arranged far from the kiosk have mutually different phases.
5. The system of claim 4 , wherein a signal phase delay value applied to the plurality of circular polarized antennas of the 2×2 array is 0 for two of the plurality of circular polarized antennas positioned at a rear of the body of the kiosk and within a range of −45°˜−65° for two circular polarized antennas positioned at the front of the body of the kiosk.