KR101569161B1 - An improved high frequency antenna - Google Patents

Abstract

The present invention discloses an antenna having an extended read range for RFID, comprising: a tuning circuit (101) for setting an operating frequency and a read range; An antenna whose size can be customized and aligned by the circuit to follow the desired read range performance; A coaxial cable 103 having a first terminal connected to the tuning circuit 101 and a second terminal connected to the computer 107 by a connector 105 connected to the high frequency reader 106; A housing; And application software for reading and displaying information.

Description

An improved high frequency antenna {AN IMPROVED HIGH FREQUENCY ANTENNA}

The present invention relates to radio frequencies. More particularly, the present invention relates to an improved antenna having an extended read range for radio frequency identification (RFID) implementation.

RFID is theoretically similar to bar code identification. In the case of RFID, electromagnetic coupling in the radio frequency portion of the electromagnetic spectrum is used to transmit signals. Typically, an RFID system consists of an antenna or coil, a transceiver having a decoder, and an electronically programmed transponder or RF tag with unique information.

An antenna activates the tag to emit radio signals to read or write data to the tag. The antennas are conduits between the tag and the transceiver, which control the data acquisition and communication of the system. Various shapes and sizes of antennas are available, which can be embedded in the door frame to receive tag data from people or installed in specially designed sidewalks in shopping malls. The electromagnetic field generated by the antenna may be continuously present when a plurality of tags are continuously predicted. RFID tags can be of a wide variety of shapes and sizes. The animal tracking tags inserted into the skin can be small in diameter with a pencil diameter and a length of 1/2 inch.

The great advantages of all types of RFID systems are non-contact and non-line-of-sight (NIOS) technologies. Tags can also be read through such a wide variety of objects such as bar codes or other optically readable technologies such as eye, fog, paint and other visually and environmentally challenging conditions. The read / write performance of an active RFID system has great advantages for such interactive applications such as inventory or maintenance tracking. Although expensive (compared to bar codes), RFID is becoming indispensable for a wide range of automated data collection and identification applications that were otherwise unavailable.

However, commercially available RFID systems have limited read range characteristics and fixed antenna size. This type of implementation limits the use of RFID and thus does not maximize the potential of the technology. It is highly desirable to provide an RFID implementation with improved read range characteristics and customizable antenna size to address these disadvantages.

A first object of the present invention is to provide a high frequency antenna with extended read range capability.

A second object of the present invention is to provide an antenna capable of customizing the size and shape.

According to an aspect of the invention, a high frequency antenna is provided that has extended read range capability by using a tuning circuit that can set the operating frequency according to the desired implementation.

According to another aspect of the present invention, there is provided an antenna having a size and shape that can be customized by arranging the antenna circuit to follow the desired read range performance.

1 is a schematic diagram showing an implementation of a high-frequency antenna according to an embodiment of the present invention.
2 is a perspective view of a high-frequency antenna according to an embodiment of the present invention.

1, the high frequency antenna of the present invention includes a tuning circuit 101, an antenna 102, a coaxial cable 103 having a variable length, a plastic case 104, and a male BNC connector 105, Which is connected to a high frequency (HF) reader 106, which serves as an intermediate device for obtaining information from the antenna 102 and for transmitting information to application software installed in the computer. The connection between the computer and the HF reader is via RS232.

The tuning circuit 101 is used to set the desired frequency for the operations of the RFID. This operating frequency is critical to the successful implementation of the present invention and the RF tag also operates at the same frequency that allows the circuit board or antenna 102 to read information from the RF tag. The present invention operates at an impedance of 50 ohm, at a frequency of 13.56 MHz, but is not limited solely to this frequency. This frequency can be tuned for several different implementations.

In Fig. 1, the tuning circuit 101 is connected by a circuit to a loop of an antenna 102 made of copper tape. The antenna 102 operates the RFID tags to read information from the RF tag and relay this information to the application software via the high frequency reader 106 using the coaxial cable 103. The application software may display information from the RF tag, write information to the RF tag, and enable / disable security measures. The antenna 102 used in the present invention includes antenna loops made of copper and such other fixed elements such as variable capacitors, resistors, high-speed switching diodes.

The resonance tuning of the 13.56 MHz circuit board or antenna 102 is achieved using a mica capacitor of approximately 100 pF. The fixed elements include capacitors whose values range vary from 10 nF to 60 nF, all of which are connected in parallel to enable tuning of the antenna 102. The capacitor legs are modified to be able to be soldered. A thick film resistor of 40 KΩ and 2 Watt adjusts the Q factor of the antenna 102. The Q factor is generally used to measure the output of the antenna 102. The switching diode is used to switch frequency bands.

The antenna 102 is inherently shaped to follow the plastic case 104, allowing a large read radius of up to 30 cm from the base. The antenna 102 can be customized to fit different sizes and different read radii, which is one of the novel features of the present invention.

Information relay from the antenna 102 to the application software is performed using a coaxial cable 103 connected to the tuning circuit 101 and this information is sent to the computer 107 via the frequency reader 106, The coaxial cable is terminated at the BNC connector 105. The most commercially available computers include a female BNC connector receiver built into the circuit board, which does not require any additional hardware cost to implement the invention. In addition, the plastic case 104 used in the present invention provides advantages in terms of weight and mobility while maintaining overall durability, as well as protecting the antenna and tuning circuit.

Referring to FIG. 2, in a preferred embodiment of the present invention, the high-frequency antenna 201 is in the form of a cube surrounded by the housing 202. The coaxial cable 203 extends out of the housing 202 and is connected to a computer (not shown) through a high frequency reader 106. Preferably, the housing 202 is 32 cm x 39.5 cm x 3.1 cm in size, but is not necessarily limited thereto.

The present invention will now be described on the basis of embodiments.

Example

In a preferred embodiment, the invention may be used to track tagged books in a library. These books can be checked in for checkout and return for rental. The antenna can read about 30 cm from the base so that many books can be read at a time. This depends on the thickness of each book. All scanned books from the antenna will display book information and borrower details via application software running on a standard computer.

The antenna can also be used to activate or deactivate a surveillance system, i.e., an automatic goods surveillance system (EAS), which is an antitheft characteristic available in an RFID tag. Typically, EAS systems are used to electronically detect when a tag is removed from a retail store, even though it is not allowed. In this application, the system can detect if books leave the library without checking out first (or if EAS is disabled when book rental). If the book passes through the gate antenna with the EA 's Enabling and the book passes through the gate antenna, an alarm will be echoed to the library manager informing the book that the book will be taken out of the library by the illegal person or borrowed unauthorized.

101: Tuning circuit
102: Antenna
103, 203: Coaxial cable
104: Plastic case
105: BNC connector
106: Frequency reader
201: High frequency antenna
202: housing

Claims (1)

An antenna having an extended read range for RFID,
A tuning circuit 101 for setting an operating frequency and a reading range;
An antenna whose size can be customized and aligned by the circuit to follow the desired read range performance;
A tuning circuit (101) having a first terminal, the tuning circuit comprising two or more variable capacitors connected in parallel with each other for tuning the antenna, a resistor for adjusting the Q factor of the antenna, and a switch for switching frequency bands A coaxial cable 103 connected to the computer 107 by a connector 105 connected to the high frequency reader 106 and having a second terminal connected to the high frequency reader 106;
A housing; And
And application software for reading and displaying information,
Wherein the at least two variable capacitors are in the range of 10 nF to 60 nF, and wherein the resistors are 40K?, 2Watt thick film resistors.

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