KR20110008478A - Rfid antenna and mobile terminal using the same - Google Patents

Abstract

PURPOSE: An RFID antenna and a terminal thereof are provided to minimize the loss of a signal by reducing the interval of transmission lines between an RFID tag IC and an RFID antenna. CONSTITUTION: An antenna pattern comprises a reduced width antenna pattern(A2) and a wide width antenna pattern(A1). The wide width antenna pattern is connected to the reduced width antenna pattern. The antenna pattern is implemented on the two dimensional plane without the intersection of the antenna pattern. The antenna pattern is serially connected to a first and second power supply terminal. An antenna pattern bottleneck part is formed in the vicinity of the power supply terminal.

Description

RDF antenna and mobile terminal using same {RFID ANTENNA AND MOBILE TERMINAL USING THE SAME}

The present invention relates to a radio frequency identification (RFID) antenna and a mobile terminal capable of RFID communication using the same.

As terminals, such as personal computers, laptops, and mobile phones, are diversified in functions, multimedia devices having complex functions such as taking pictures or videos, playing music or video files, playing games, and receiving broadcasts are provided. ) Is implemented.

Terminal can move It may be divided into a mobile terminal and a stationary terminal, depending on whether it is present. The mobile terminal may be divided into a handheld terminal and a vehicle mount terminal according to whether a user can directly carry it.

Recently, a mobile terminal incorporating Near Field Communication (NFC) technology is commercially available. Such a mobile terminal may be used not only for use in the existing mobile terminal but also for the purpose of payment of prepaid and unpaid transportation charges, credit settlement, electronic bank account, copyright management, identity verification, and the like. NFC is a contactless short range wireless communication technology that can transmit data at low power over short distances using Radio-Frequency IDentification (RFID) technology that uses a frequency in the 13.56 MHz band.

A mobile terminal incorporating NFC technology requires a tag chip in which user identification information and payment information are stored, and an RFID antenna that transmits data of the tag chip and generates electromotive force by radio waves received from an external reader. RFID antennas are generally implemented as antennas in a loop or spiral form.

RFID antennas in a loop or spiral form include patterns that intersect at least one part because they draw concentric circles in one direction. These crossing patterns must be electrically insulated from each other. Due to the crossing patterns, the manufacturing process of the RFID antenna is performed by forming a copper foil antenna pattern on the front and rear surfaces of the substrate, drilling the via holes, and plating copper through the via holes to connect the broken copper foil patterns near the intersections. It includes a process to make.

Since the RFIC antenna has to connect the copper foil pattern through the via holes in the vicinity of the intersection, the thickness of the RFIC antenna is inevitably thick. The manufacturing process of the RFID antenna is complicated and numerous in number due to the via hole drilling and copper plating in the via hole.

An object of the present invention is to provide an RFID antenna and a mobile terminal using the same that can be implemented in a single-layer two-dimensional plane and to minimize signal loss.

As an aspect of the present invention, the RFID antenna of the present invention includes: first and second feed terminals; An antenna pattern narrowing in width between the feed terminals; And a substrate on which the feed terminals and the antenna pattern are formed.

The mobile terminal of the present invention comprises: first and second feed terminals; An antenna pattern narrowing in width between the feed terminals; A substrate on which the feed terminals and the antenna pattern are formed; And a smart card having a built-in RFID tag IC connectable to the feed terminals.

The present invention allows a portion of the antenna patterns to cross between the feed terminals so that there is no intersection between the antenna patterns, and narrows the width of the antenna pattern across the feed terminals so that the distance between the feed terminals does not increase. . As a result, the RFID antenna of the present invention and a mobile terminal using the same can be implemented on one surface of the substrate and can minimize signal loss.

The above objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like numbers refer to like elements throughout. In addition, when it is determined that the detailed description of the known function or configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, a mobile terminal according to the present invention will be described in more detail with reference to the accompanying drawings. The suffixes "module" and "unit" for components used in the following description are given or used in consideration of ease of specification, and do not have distinct meanings or roles from each other.

The mobile terminal described herein may include a mobile phone, a smart phone, a notebook computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation terminal, and the like.

1 illustrates a mobile terminal according to an embodiment of the present invention.

Referring to FIG. 1, the mobile terminal 100 includes a wireless communication unit 110, an A / V input unit 120, a user input unit 130, a sensing unit 140, an output unit 150, and a memory. The unit 160, an interface unit 170, a controller 180, and a power supply unit 190 may be included. The configuration of the mobile terminal 100 is not limited to only the components shown in FIG. 1, and more components may be added or some components may be omitted according to a function added or omitted in the mobile terminal.

The wireless communication unit 110 may include one or more modules that enable wireless communication between the mobile terminal 100 and the wireless communication system or between the mobile terminal 100 and a network in which the mobile terminal 100 is located. For example, the wireless communication unit 110 may include a broadcast receiving module 111, a mobile communication module 112, a wireless internet module 113, and a short-range communication module. communication module 114 and position-location module 115.

The broadcast receiving module 111 receives a broadcast signal and / or broadcast related information from an external broadcast management server through a broadcast channel. The broadcast channel may include a satellite channel and a terrestrial channel. The broadcast management server may mean a server that generates and transmits a broadcast signal and / or broadcast related information or a server that receives a previously generated broadcast signal and / or broadcast related information and transmits the same to a terminal. The broadcast signal may include not only a TV broadcast signal, a radio broadcast signal, and a data broadcast signal, but also a broadcast signal having a data broadcast signal combined with a TV broadcast signal or a radio broadcast signal.

The broadcast related information may mean information related to a broadcast channel, a broadcast program, or a broadcast service provider. The broadcast related information may also be provided through a mobile communication network. In this case, broadcast related information may be received by the mobile communication module 112.

The broadcast related information may exist in various forms. For example, it may be produced in the form of Electronic Program Guide (EPG) of Digital Multimedia Broadcasting (DMB) or Electronic Service Guide (ESG) of Digital Video Broadcast-Handheld (DVB-H).

The broadcast receiving module 111 receives a broadcast signal using various broadcasting systems, in particular, Digital Multimedia Broadcasting-Terrestrial (DMB-T), Digital Multimedia Broadcasting-Satellite (DMB-S), and Media Forward Link Only (MediaFLO). ), Digital broadcast signals may be received using digital broadcasting systems such as DVB-H (Digital Video Broadcast-Handheld) and ISDB-T (Integrated Services Digital Broadcast-Terrestrial). Of course, the broadcast receiving module 111 may be configured to be suitable for not only the above-described digital broadcast system but also other broadcast system for providing a broadcast signal.

The broadcast signal and / or broadcast related information received through the broadcast receiving module 111 may be stored in the memory unit 160.

The mobile communication module 112 transmits and receives a radio signal with at least one of a base station, an external terminal, and a server on a mobile communication network. The wireless signal may include various types of data such as voice call signal, video call signal or text / multimedia message transmission and reception.

The wireless internet module 113 refers to a module for wireless internet access. The wireless internet module 113 may be embedded or external to the mobile terminal 100. Wireless Internet technologies may include Wireless LAN (Wi-Fi), Wireless Broadband (Wibro), World Interoperability for Microwave Access (Wimax), High Speed Downlink Packet Access (HSDPA), and the like.

The short range communication module 114 means a module for short range communication. Here, the short-range communication module 114 is not using NFC technology using RFID technology, but Bluetooth, Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra Wideband (UWB), ZigBee, etc. Uses near field communication technology.

The location information module 115 is a module for confirming or obtaining the location of the mobile terminal. A representative example of the location information module is a GPS (Global Position System) module. According to the current technology, the GPS module 115 calculates information about a distance of a point (object) from three or more satellites, and information on a time at which the distance information is measured, and then triangulates the calculated distance information. By applying, three-dimensional position information according to latitude, longitude, and altitude of one point (object) can be calculated in one time. Furthermore, a method of calculating position and time information using three satellites and correcting the error of the calculated position and time information using another satellite is also used. The GPS module 115 may continuously calculate the current position in real time and use the same to calculate speed information.

The A / V input unit 120 is for inputting an audio signal or a video signal, and may include a camera 121 and a microphone 122. The camera 121 processes image frames such as still images or moving images obtained by the image sensor in the video call mode or the photographing mode. The processed image frame may be displayed on the display module 151.

The image frame processed by the camera 121 may be stored in the memory unit 160 or transmitted to the outside through the wireless communication unit 110. Two or more cameras 121 may be disposed in the mobile terminal 100.

The microphone 122 receives an external sound signal by a microphone in a call mode, a recording mode, a voice recognition mode, etc., and processes the external sound signal into electrical voice data. The processed voice data may be converted into a form transmittable to the mobile communication base station through the mobile communication module 112 and output in the call mode. The microphone 122 may implement various noise removing algorithms for removing noise generated in the process of receiving an external sound signal.

The user input unit 130 generates input data for the user to control the operation of the terminal. The user input unit 130 may include a key pad, a dome switch, a touch pad, a jog wheel, a jog switch, and the like. In addition, the user input unit 130 may include a trackball, a joystick, and the like. The sensors of the sensing unit 140 may also function as an input unit capable of inputting a user's command for selecting and controlling 3D objects.

The sensing unit 140 may include an open / closed state of the mobile terminal 100, a position of the mobile terminal 100, presence or absence of a user contact, orientation of the mobile terminal, acceleration / deceleration of the mobile terminal, change of movement of the mobile terminal, and change of angle of the mobile terminal. By sensing the current state of the mobile terminal 100, such as to generate a sensing signal for controlling the operation of the mobile terminal 100. In addition, the sensing unit 140 may generate a sensing signal related to whether the power supply unit 190 supplies power or whether the interface unit 170 is coupled to an external device.

The sensing unit 140 may include a touch screen including a touch sensor embedded in the display module 151 or stacked on the display module 151, the presence or absence of an object within a recognized proximity distance on the display module 151 or the touch screen, and It may include a proximity sensor for detecting the movement or gesture of the object. In addition, the sensing unit 140 may include a gyro sensor, a geomagnetic sensor, or the like that detects a change in movement, a change in orientation, and a change in angle of the mobile terminal 100.

The output unit 150 is used to generate an output related to visual, auditory, or tactile, and may include a display module 151, an audio output module 152, an alarm unit 153, and a haptic module 154. have.

The display module 151 displays and outputs information processed by the mobile terminal 100. For example, the display module 151 may display a user interface (UI), a 2D and a 3D graphic user interface (GUI), and the like under the control of the controller 180. When the mobile terminal 100 is in a video call mode or a photographing mode, the display module 151 may display an image photographed by the camera 121 or an image received through the wireless communication unit 110.

The display module 151 includes a liquid crystal display (LCD), a thin film transistor liquid crystal display (TFT LCD), an organic light emitting diode (OLED), a flexible display, 3 It may include at least one of a 3D display.

The display module 151 may be configured to be transparent or light transmissive so that the outside can be seen through the display panel. In this case, the user may see an object located behind the terminal body through the area occupied by the display module 151 of the mobile terminal body.

The touch screen may be implemented in a form in which a touch sensor is stacked on the display module 151 or a touch sensor is embedded in the display module 151. The touch screen may be used as an input device that receives a user input in addition to the image output device.

The touch sensor may be configured to convert a change in pressure applied to a specific portion of the display unit 151 or capacitance generated in a specific portion of the display unit 151 into an electrical input signal. The touch sensor may be configured to detect not only the position and area of the touch but also the pressure at the touch. When there is a touch input to the touch sensor, the signal (s) corresponding thereto are transmitted to the controller 180. The controller 180 calculates the coordinates of the touch point and the touch pressure from the output signal of the touch sensor. As a result, the controller 180 can know which point is touched on the touch screen and can also know what pressure the touch screen is touched. When the touch sensor is implemented as a capacitive touch sensor, the proximity of the pointer may be sensed by the change of the electric field according to the proximity of the pointer. In this case, the touch screen may be classified as a proximity sensor.

The proximity sensor may be disposed inside or near the touch screen. The proximity sensor refers to a sensor that detects the presence or absence of an object approaching a predetermined detection surface or an object present in the vicinity without using a mechanical contact by using an electromagnetic force or infrared rays. Proximity sensors have a longer life and higher utilization than touch sensors. The proximity sensor may be a transmission photoelectric sensor, a direct reflection photoelectric sensor, a mirror reflection photoelectric sensor, a high frequency oscillation proximity sensor, a capacitive proximity sensor, a magnetic proximity sensor, an infrared proximity sensor, or the like.

The proximity sensor senses proximity touch and proximity touch patterns (eg, proximity touch distance, proximity touch direction, proximity touch speed, proximity touch time, proximity touch position, proximity touch movement state, and the like). Information corresponding to the sensed proximity touch operation and proximity touch pattern may be output on the touch screen.

The sound output module 152 may output audio data received from the wireless communication unit 110 or stored in the memory unit 160 in a call signal reception, a call mode or a recording mode, a voice recognition mode, a broadcast reception mode, and the like. The sound output module 152 outputs an acoustic signal related to a function (e.g., a call signal reception sound, a message reception sound, etc.) performed in the mobile terminal 100. The sound output module 152 may include a receiver, a speaker, a buzzer, and the like.

The alarm unit 153 outputs a signal for notifying occurrence of an event of the mobile terminal 100. Examples of events occurring in the mobile terminal include call signal reception, message reception, key signal input, touch input, proximity input, and the like. The alarm unit 153 may output a signal for notifying occurrence of an event in a form other than a video signal or an audio signal, for example, vibration. The video signal or the audio signal may also be output through the display unit 151 or the sound output module 152.

The haptic module 154 generates various tactile effects that the user can feel. Vibration is a representative example of the haptic effect generated by the haptic module 154. The intensity and pattern of the vibration generated by the haptic module 154 are controllable. For example, different vibrations may be synthesized and output or may be sequentially output. In addition to vibration, the haptic module 154 has the effect of stimulation by the arrangement of pins vertically moving with respect to the contact skin surface, the effect of stimulation through the injection force or the suction force of air through the injection or inlet, and the effect by the stimulus that rubs the skin surface. Various effects of tactile sensation may be generated, such as an effect of stimulation through contact of an electrode, an effect of stimulation using an electrostatic force, and an effect of reproducing a sense of cold and warm using an endothermic or heat generating element. The haptic module 154 may not only deliver the haptic effect through direct contact, but also may realize the haptic effect through the muscle sense of the user's finger or arm.

The memory 160 may store a program for processing various control operations of the controller 180. In addition, the memory 160 stores data of a plurality of user interface modes that are switched under the control of the controller 180, and data such as phonebooks, messages, still images, and videos input / output under the control of the controller 180. Is stored. In addition, the memory 160 stores basic setting data such as a ringtone, a ringtone type data, an alarm data, an alarm type data, a calendar data, and schedule data. The memory 160 may store data related to sound effects of various patterns and haptic patterns output during touch input, proximity input, and the like. The memory 160 may be a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (for example, SD or XD memory), RAM Random Access Memory (RAM), Static Random Access Memory (SRAM), Read-Only Memory (ROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Programmable Read-Only Memory (PROM) magnetic memory, Magnetic disk It may include at least one type of storage medium of the optical disk. The mobile terminal 100 may operate in association with a web storage that performs a storage function of the memory 160 on the Internet.

The interface unit 170 serves as a path with all external devices connected to the mobile terminal 100. The interface unit 170 receives data from an external device or receives power from the external device to transfer the data to each component in the mobile terminal 100 or to transmit data in the mobile terminal 100 to an external device. For example, wired / wireless headset port, external charger port, wired / wireless data port, memory card port, identification module card port, audio input / output (I / O) port, video I / O (Input / Output) port, earphone port may be included in the interface unit 170. When the mobile terminal 100 is connected to an external cradle, the interface unit 170 may be a passage through which power from the cradle is supplied to the mobile terminal 100, or various command signals input from the cradle by a user may be used. It may be a passage that is delivered to the mobile terminal 100. Various command signals or power input from the cradle may be operated as signals for recognizing that the mobile terminal 100 is correctly mounted on the cradle.

The identification module is a chip that stores various information for authenticating the use authority of the mobile terminal 100, and includes a user identification module (UIM), a subscriber identify module (SIM), and a universal user authentication module (SIM). Universal Subscriber Identity Module (USIM), and the like. The identification module may be manufactured in the form of a smart card. The identification module may be detachably connected to the mobile terminal 100 through the identification module port of the interface unit 170. The identification module stores user identification information, phone number, call information, billing information, and the like. In addition, the identification module stores an RFID tag IC for storing various information necessary for RFID communication and transmitting data. The identification module is connected to the RFID antenna as shown in FIGS. 3 and 5 to 8.

The controller 180 controls the overall operation of the mobile terminal 100. For example, the controller 180 performs related control and processing for voice call, data communication, video call, and the like, and analyzes the outputs of the user input unit 130 and the sensing unit 140 to switch the user interface mode. . The controller 180 may include a multimedia module 181. The multimedia module 181 is responsible for signal processing for reproduction of multimedia data. The controller 180 performs pattern recognition processing for recognizing a writing input or a drawing input performed on a touch screen, respectively, as a character and an image, storing the memo, a message, and a graphic image in the form of a wireless communication unit 110 according to a user selection. Can be transmitted to other desired wireless communication subscribers.

The power supply unit 190 receives an external power source and an internal power source under the control of the controller 180 to supply power for operation of each component.

The mobile terminal 100 according to the present invention has a bar structure, a bar type, a folder type, a slide type, a swivel type, a swing type, and the like. It may be implemented in any form. 2A and 2B are external perspective views illustrating an example of a bar type mobile terminal equipped with a full touch screen. It should be noted that the present invention is not limited to the appearance structure.

2A is a front perspective view of an example of the mobile terminal 100.

The body includes a case (casing, housing, cover, etc.) that forms an image. The case may be divided into a front case 101 and a rear case 102. Various electronic components are built in the space formed between the front case 101 and the rear case 102. At least one intermediate case may be additionally disposed between the front case 101 and the rear case 102. [

The cases may be manufactured by injecting a synthetic resin or may be made of a metal material, for example, a metal material such as stainless steel (STS) or titanium (Ti).

The front case 101 may include a display module 151, an audio output unit 152, a camera 121, a plurality of manipulation units 131 and 132, a microphone 122, an interface 170, and the like. have.

The display module 151 occupies most of the main surface of the front case 101. The sound output unit 152 and the camera 121 are disposed in regions adjacent to one end of both ends of the display unit 151, and the first operation unit 131 and the microphone 122 are disposed in regions adjacent to the other end. . The second operation unit 132, the interface 170, and the like are disposed on the sides of the front case 101 and the rear case 102.

The user input unit 130 is manipulated to receive a command for controlling the operation of the portable terminal 100 and may include a plurality of operation units 131 and 132. The manipulation units 131, 132 can be employed in any manner as long as the manner in which the user is manipulated while making the user feel a change in tactile sense. For example, the manipulation units 131, 132 may include a keypad, a dome switch, a touch pad, a jog wheel, a jog switch, a trackball, a joystick, and the like.

Content input by the operation units 131 and 132 may be variously set. For example, the first operation unit 131 receives commands such as start, end, scroll, and the like, and the second operation unit 132 controls the size of the sound output from the sound output unit 152 or the size of the sound output from the display unit 151 To the touch recognition mode of the touch screen. These operation units may include an operation unit for displaying 3D map data, an operation unit for selecting and controlling a 3D object, and the like.

FIG. 2B is a rear perspective view of the mobile terminal 100 shown in FIG. 2A.

Referring to FIG. 2B, a camera 121 ′ may be additionally mounted on the rear case 102. The camera 121 ′ may be a camera having a photographing direction substantially opposite to the front camera 121 (see FIG. 2A) and having different pixels from the camera 121.

For example, the camera 121 has a low pixel so that the user's face is photographed and transmitted to the counterpart in case of a video call, and the camera 121 'photographs a general subject and does not transmit it immediately. It is desirable to have a high pixel because there are many. The cameras 121 and 121 'may be installed in the terminal body to be rotatable or pop-up.

A flash 123 and a mirror 124 may be additionally disposed adjacent to the camera 121 '. The flash 123 shines light toward the subject when the subject is photographed by the camera 121 '. The mirror 124 allows the user to see his / her own face or the like when photographing (self-photographing) the user using the camera 121 '.

The sound output unit 152 ′ may be further disposed on the rear surface of the rear case 102. The sound output unit 152 ′ may implement a stereo function together with the front sound output unit 152 (see FIG. 2A), and may be used to implement a speakerphone mode during a call.

The antenna for receiving a broadcast signal may be additionally disposed on the side of the body of the mobile terminal. An antenna constituting a part of the broadcast receiving module 111 of FIG. 1 may be installed to be pulled out of the mobile terminal body.

The mobile terminal body is equipped with a power supply unit 190 for supplying power to the portable terminal 100. The power supply unit 190 may be embedded in the terminal body or may be directly detachable from the outside of the terminal body.

The rear case 102 may be further equipped with a touch pad 135 for sensing a touch. Like the display unit 151, the touch pad 135 may also be configured to have a light transmission type. If the display unit 151 is configured to output visual information from both sides, the visual information may be recognized through the touch pad 135. The information output on both surfaces may be controlled by the touch pad 135. Alternatively, a display may be additionally mounted on the touch pad 135, and a touch screen may be disposed on the rear case 102.

The touch pad 135 operates in association with the display unit 151 of the front case 101. The touch pad 135 may be disposed in parallel to the rear of the display unit 151. The touch pad 135 may have the same or smaller size as the display unit 151.

The rear case 102 is provided with a battery pack storage space. In the battery pack storage space, a battery pack is detachably fastened, and a socket for detachably fastening the smart card including the identification module and the RFID tag IC is installed. The rear case 102 is detachably fastened with a battery cover for opening and closing the battery pack storage space.

3 is an equivalent circuit diagram illustrating a smart card 10, a transmission line, and an RFID antenna 11 implemented in the mobile terminal 100.

Referring to FIG. 3, the RFID tag IC of the smart card 10 includes a load resistor R _L , a switch SW, an IC capacitor C _IC , and the like. The RFID tag IC of the smart card 10 is connected to the RFID antenna 11 through a transmission line in which a tune capacitor C _tune is connected in parallel. The switch SW connects the load resistor R _L to the transmission line according to the digital modulation data stored in the identification module. When the switch SW is turned on / off by modulated digital data bits, the H-field of radio waves transmitted from the RFID antenna 11 to the RFID reader is changed while the efficiency of the RFID antenna 11 is changed. Is changed. The RFID reader sends out a 13.56 MHz time sine wave and detects a change in the H field reflected from the RFID antenna 11. The received voltage of the RFID reader changes according to the flux change and the impedance change seen from the RFID reader. 4 shows the change in impedance Z seen by the RFID reader when the load resistor R _L is turned on / off. The RFID antenna 11 is implemented with a single layer loop antenna as shown in FIGS. 5 to 8.

The circuit of FIG. 3 includes an LC parallel resonant circuit and has a resonance frequency characteristic as shown in Equation 1 below.

Here, C = C _IC + C _tune , L is the inductance value of the RFID antenna (11).

The performance of the RFID system depends on the recognition distance of the RFID antenna 11. The recognition distance of the RFID antenna 11 becomes longer as the induced voltage generated by the radio waves received from the RFID antenna 11 increases. The induced electromotive force generated by the RFID antenna 11 may be described by Faraday's law as shown in Equation 2 below.

Where V is induced voltage, Ψ is flux linkage, B is magnetic flux density, μ is permeability, r is distance from coil, N is number of turns of turn, L denotes inductance, f denotes frequency, α denotes flux and S angle, respectively. S is the coil aperture area (S = a × b) in FIG. 5.

As can be seen from Equation 2, the induced electromotive force of the RFID antenna 11 is a method of increasing the number of coil turns, increasing the L component or lowering the R component to increase the Q value, increasing the opening area S, and permeability μ Increase the value of B, and so on. The opening area S is limited due to the size of the mobile terminal, which is limited, and the B value cannot be adjusted because the permeability of the antenna material is constant. Therefore, as a method for increasing the induced electromotive force of the RFID antenna 11, a method of increasing the number of coil turns of the loop antenna or a method of increasing the Q value is preferable.

In order to increase the induced electromotive force of the RFID antenna 11, simply increasing the number of coil turns of the RFID antenna 11 has the following problems. Implementing the RFID antenna 11 on a two-dimensional plane of a single layer and increasing the number of turns increases the distance between the two feed terminals. As the distance between the feed terminals of the RFID antenna 11 increases, the distance between two signal lines increases and the characteristic impedance of the transmission line increases. As a result, the impedance discontinuity between the RFID antenna 11 and the transmission line, the transmission line, and the RFID tag IC increases, resulting in a large signal loss. As a result, the change in the ON / OFF resistance of the switch viewed from the RFID reader is relatively large. Smaller recognition distance and recognition rate fall.

The present invention implements an RFID antenna on a two-dimensional plane of a single layer as shown in FIGS. The increase in distance between the feed terminals can be minimized. The RFID antenna 11 of the present invention will be described in detail with reference to FIGS. 5 to 8.

5 is a plan view of the RFID antenna 11 according to the first embodiment of the present invention. FIG. 6 is an enlarged plan view of the feeding part 11a of the RFID antenna 11 in FIG. 5.

5 and 6, antenna patterns A1 and A2 implemented on a single-layer two-dimensional plane without intersections of the antenna patterns of the present invention, and feed terminals F + connected to the antenna patterns A1 and A2. , F-).

Differential signals are applied to the first and second feed terminals F + and F- from the RFID tag IC of the smart card through the transmission line. The antenna patterns A1 and A2 are connected in series to the first and second feed terminals F + and F−.

Some of the antenna patterns A1 and A2 have narrow widths so that the first and second feed terminals F + and F− are narrow so that there is no intersection in the antenna pattern and the distance between the feed terminals F + and F− is narrow. Traverse between) To this end, the antenna patterns A1 and A2 are connected to the narrow antenna pattern A2 across the feed terminals F + and F-, and the narrow antenna pattern A2 and between the feed terminals F +. A wide antenna pattern A1 that does not traverse is included.

In FIG. 6, 't1' is the width of the wide antenna pattern A1, 't2' is the width of the narrow antenna pattern A2, 'd1' is the distance between neighboring narrow antenna patterns A2, 'd2' Denotes the distance between the feed terminals F + and F-, respectively. In the vicinity of the feed terminals F + and F−, an antenna pattern bottleneck forming a boundary between the wide antenna pattern A1 and the narrow antenna pattern A2 is formed.

Due to the narrow antenna pattern A2 crossing a narrow width between the two feed terminals F + and F-, as shown in FIG. 6, the RFID antenna 11 of the present invention has no cross section of the antenna pattern. Not only can be implemented on the dimensional plane, but also the winding of the antenna patterns A1 and A2 across the feed terminals F + and F- without increasing the distance between the two feed terminals F + and F-. You can increase your player sufficiently. On the other hand, due to the narrow antenna pattern A2, the resistance component is slightly increased, which may cause ohmic loss. However, the loss is very small and the transmission line is reduced by reducing the transmission line spacing between the RFID tag IC and the RFID antenna. Signal losses can be minimized by lowering the characteristic impedance of.

The antenna patterns A1 and A2 may be patterned into various shapes such as a square pattern as shown in FIG. 5, a square pattern with rounded corners as shown in FIG. 7, and an octagonal pattern as shown in FIG. 8.

Since the RFID antenna 11 is implemented on the two-dimensional plane of the substrate monolayer without the intersection as described above, it may be inserted into the resin of the battery cover or the battery pack by the in-mold process as shown in FIGS. 9A and 9B. have. The feed terminals of the RFID antenna 11 inserted into the resin of the battery case or the battery pack may be exposed as shown in FIG. 9B and may be connected to the smart card through the connection terminal. In addition, the RFID antenna 11 may be printed on the surface of the battery case or battery pack through a printing process as shown in FIG.

In the RFDI antenna 11 illustrated in FIGS. 9A to 10, the width t2 of the narrow antenna pattern A2 is 0.2 mm, the distance d1 between neighboring narrow antenna patterns A2 is 0.2 mm, and the feed terminals F +. , The distance d2 between F-) was set to 1.4 mm, respectively.

Although the RFID antenna 11 of the present invention exemplifies an example applied to a mobile terminal in the embodiment, the present invention is not limited thereto, and the RFID antenna 11 may be applied to any RFID system to which an RFID antenna is applicable.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

1 is a block diagram illustrating a mobile terminal according to an embodiment of the present invention.

Figure 2a is a front perspective view of a mobile terminal according to an embodiment of the present invention.

Figure 2b is a rear perspective view of a mobile terminal according to an embodiment of the present invention.

3 is an equivalent circuit diagram illustrating an RFID system including a smart card, an RFID antenna, and an RFID reader.

4 is a graph showing the impedance change seen from the RFID reader during the load resistance ON / OFF operation.

5 is a plan view showing an RFID antenna according to a first embodiment of the present invention.

FIG. 6 is an enlarged plan view of the antenna feeding portion 11a in FIG. 5.

7 is a plan view illustrating an RFID antenna according to a second embodiment of the present invention.

8 is a plan view illustrating an RFID antenna according to a third embodiment of the present invention.

9A and 9B are images illustrating an example of implementing the RFID antenna of FIG. 5 in an in-mold type.

FIG. 10 is an image illustrating an example of implementing the RFID antenna illustrated in FIG. 5 in a print type.

<Explanation of symbols for the main parts of the drawings>

10: smart card (identification module 11: RFID antenna

Claims (8)

First and second feed terminals; An antenna pattern narrowing in width between the feed terminals; And And a substrate on which the feed terminals and the antenna pattern are formed. The method of claim 1, The antenna pattern is, A plurality of first antenna patterns intersecting between the feed terminals; A plurality of second antenna patterns connecting the first antenna patterns to the feed terminals in series; The width of the first antenna pattern is smaller than the width of the second antenna pattern RFID antenna. The method of claim 1, And the antenna pattern and the feed terminals are formed only on one surface of the substrate. First and second feed terminals; An antenna pattern narrowing in width between the feed terminals; A substrate on which the feed terminals and the antenna pattern are formed; And And a smart card having an embedded RFID tag IC connectable to the feed terminals. The method of claim 4, wherein The antenna pattern is, A plurality of first antenna patterns intersecting between the feed terminals; A plurality of second antenna patterns connecting the first antenna patterns to the feed terminals in series; The width of the first antenna pattern is a mobile terminal, characterized in that less than the width of the second antenna pattern. The method of claim 4, wherein Wherein: A mobile terminal comprising any one of a battery pack and a battery cover. The method of claim 4, wherein The antenna pattern and the feed terminal is formed on only one surface of the substrate. The method of claim 4, wherein The smart card, A mobile terminal comprising any one of a user identification module (UIM), a subscriber identify module (SIM), and a universal subscriber identity module (USIM).

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