KR20150118481A - Antenna device of a mobile terminal - Google Patents

Abstract

The present invention relates to an antenna device for a mobile terminal. The antenna device comprises: a printed circuit board; a first antenna device including a first power supply line connected with a power supply unit of the printed circuit board, a first ground line connected with a ground unit of the printed circuit board, and a first antenna pattern irradiating a first RF signal; a second antenna device including a second power supply line connected with a power supply unit of the printed circuit board, a second ground line connected with the ground unit of the printed circuit board, and a second antenna pattern irradiating a second RF signal; a coupling device disposed to be spaced apart at particular intervals from the first and second antennas; and a variable circuit device connected between the coupling device and the ground unit, and constituting the coupling device and a band elimination filter.

Description

TECHNICAL FIELD [0001] The present invention relates to an antenna device for a mobile terminal,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device for a mobile terminal, and more particularly, to an antenna device for a mobile terminal capable of improving isolation between antenna elements within a limited mounting space of the terminal.

A terminal can be divided into a mobile / portable terminal and a stationary terminal depending on whether the terminal is movable or not. The mobile terminal can be divided into a handheld terminal and a vehicle mounted terminal according to whether the user can directly carry the mobile terminal.

The functions of mobile terminals are diversified. For example, there are data and voice communication, photographing and video shooting through a camera, voice recording, music file playback through a speaker system, and outputting an image or video on a display unit. Some terminals are equipped with an electronic game play function or a multimedia player function. In particular, modern mobile terminals can receive multicast signals that provide visual content such as broadcast and video or television programs.

Such a terminal has various functions, for example, a multimedia player having a complex function such as photographing or moving picture shooting, reproduction of music or video file, reception of game or broadcasting, . In order to support and enhance the functionality of such terminals, it may be considered to improve the structural and / or software parts of the terminal.

Meanwhile, in recent years, a built-in antenna considering the beauty of a terminal has been preferred according to the demand for miniaturization and slimness of a mobile terminal. In accordance with the demand for high-speed multimedia service, the increase of communication capacity in mobile communication system is continuously accelerating. Accordingly, there is a growing interest in an antenna technology for a broadband mobile communication system that can satisfy both the miniaturization of an antenna and the ever-increasing communication capacity and reliability of communication.

According to this trend, the proposed technique is an antenna technique using multi-input multi-output (MIMO) or diversity, which is currently in the spotlight. First, a method using MIMO is a multi-input / multiple-output method in which data is transmitted through multiple paths by increasing the number of antennas of a base station and a mobile terminal to two or more, to be. Next, the diversity scheme is a scheme of receiving signal propagation using two or more antennas and synthesizing the outputs thereof to detect a received signal. The beauty / diversity antenna with such a technique can increase the reliability of transmitted data and can overcome the limitation of the amount of mobile communication due to expansion of data communication.

However, when such a mimic / diversity antenna is used in a mobile terminal, mutual coupling between antennas occurs due to the spatial limitation of the mobile terminal, and the isolation is drastically reduced.

To solve this problem, it is conceivable to reduce the distance between the antennas by? / 2 or more (where? Is the wavelength of the radio wave radiated by the antenna). However, in the case of the built-in antenna, since the mounting space in which the antenna is installed is limited, the above problem can not be solved by a method of separating the distance between the antennas.

As another method, prior art documents suggesting a structure for improving the degree of isolation between fine and diversity antennas include US Patent No. 7,688,273 and Korean Laid-Open Patent No. 2013-0023669.

In US 7,688,273, a decoupling network (or a suspend line, 210) is connected between a monopole antenna element 202, 204 of lambda / 2 length to reduce the surface current flowing to the PCB ground Which improves the isolation of the antenna. However, in the case of the US registered patent, there is only one resonance frequency having a good isolation degree (S12) characteristic, and there is a problem that it has a poor isolation characteristic of about S12: -2 dB to -3 dB in a high frequency band of 1 GHz or more .

In Korean Patent Laid-Open Publication No. 2013-0023669, a current conversion element 130 is connected between two Planar Inverse F Antennas (PIFAs) 110 and 120 to affect the other antenna. Is a structure that improves the isolation of the antenna by reducing the surface current. However, in the case of the Korean patent, there is a problem that the isolation characteristic is improved in the low frequency band of 1 GHz or less although the high frequency band of 1 GHz or more shows a good isolation characteristic.

The present invention is directed to solving the above-mentioned problems and other problems. Another object of the present invention is to provide an antenna device capable of improving isolation between antenna elements within a limited mounting space of a mobile terminal.

Another object of the present invention is to provide an antenna device capable of improving isolation between antenna elements by implementing characteristics of a band stop filter between two adjacent antenna elements.

Another object of the present invention is to provide an antenna device capable of improving the degree of isolation between antenna elements by changing the resonance frequency of each antenna element when two adjacent antenna elements operate in the same frequency band.

According to an aspect of the present invention, there is provided a printed circuit board comprising: a printed circuit board; A first feed line connected to a feeding part of the printed circuit board, a first ground line connected to a ground part of the printed circuit board, and a first antenna pattern radiating a first RF signal, ; A second feed line connected to a feeding part of the printed circuit board, a second ground line connected to a ground part of the printed circuit board, and a second antenna pattern radiating a second RF signal, ; A coupling element disposed at a predetermined distance from the first and second antennas; And a variable circuit element connected between the coupling element and the grounding part, the variable circuit element forming the coupling element and the band elimination filter.

Effects of the mobile terminal and the control method according to the present invention will be described as follows.

According to at least one of the embodiments of the present invention, in the Multi Co-band system in which at least two antenna elements can operate in the same frequency band, the mounting of the antenna elements can be improved by changing the structure of the antenna and inserting the circuit However, there is an advantage that the degree of isolation between the antenna elements can be improved.

Meanwhile, various other effects will be directly or implicitly disclosed in the detailed description according to the embodiment of the present invention to be described later.

FIG. 1A is a block diagram illustrating a mobile terminal according to the present invention; FIG.
FIG. 1B and FIG. 1C are conceptual diagrams illustrating an example of a mobile terminal according to the present invention in different directions; FIG.
2 is a view illustrating a structure of an antenna device for a mobile terminal according to a first embodiment of the present invention;
3 is a diagram illustrating a configuration of a variable circuit element included in the antenna device according to the first embodiment of the present invention;
4 shows electrical characteristics of a band elimination filter implemented through a coupling element and a variable circuit element;
5 is a diagram showing the electrical characteristics of a band elimination filter realized by changing a coupling element and a variable circuit element in a low frequency band or a high frequency band;
6 is a diagram illustrating a configuration of a variable frequency element included in an antenna device according to a first embodiment of the present invention;
7 is a view schematically showing a structure of a conventional antenna device for a mobile terminal;
8 is a view showing a structure of an antenna device for a mobile terminal according to a second embodiment of the present invention;
9 is a view showing electrical characteristics of a conventional antenna device and an antenna device according to a second embodiment of the present invention;
10 is a view illustrating another structure of an antenna device for a mobile terminal according to a second embodiment of the present invention;

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals are used to designate identical or similar elements, and redundant description thereof will be omitted. The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role. In the following description of the embodiments of the present invention, a detailed description of related arts will be omitted when it is determined that the gist of the embodiments disclosed herein may be blurred. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. , ≪ / RTI > equivalents, and alternatives.

The mobile terminal described in this specification includes a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation device, a slate PC A tablet PC, an ultrabook, a wearable device such as a smartwatch, a smart glass, and a head mounted display (HMD). have.

However, it will be appreciated by those skilled in the art that the configuration according to the embodiments described herein may be applied to fixed terminals such as a digital TV, a desktop computer, a digital signage, and the like, will be.

1A to 1C are block diagrams for explaining a mobile terminal according to the present invention, and FIGS. 1B and 1C are conceptual diagrams showing an example of a mobile terminal according to the present invention in different directions.

The mobile terminal 100 includes a wireless communication unit 110, an input unit 120, a sensing unit 140, an output unit 150, an interface unit 160, a memory 170, a control unit 180, ), And the like. The components shown in FIG. 1A are not essential for implementing a mobile terminal, so that the mobile terminal described herein may have more or fewer components than the components listed above.

The wireless communication unit 110 may be connected between the mobile terminal 100 and the wireless communication system or between the mobile terminal 100 and another mobile terminal 100 or between the mobile terminal 100 and the external server 100. [ Lt; RTI ID = 0.0 > wireless < / RTI > In addition, the wireless communication unit 110 may include one or more modules for connecting the mobile terminal 100 to one or more networks.

The wireless communication unit 110 may include at least one of a broadcast receiving module 111, a mobile communication module 112, a wireless Internet module 113, a short distance communication module 114, and a location information module 115 .

The input unit 120 includes a camera 121 or an image input unit for inputting a video signal, a microphone 122 for inputting an audio signal, an audio input unit, a user input unit 123 for receiving information from a user A touch key, a mechanical key, and the like). The voice data or image data collected by the input unit 120 may be analyzed and processed by a user's control command.

The sensing unit 140 may include at least one sensor for sensing at least one of information in the mobile terminal, surrounding environment information surrounding the mobile terminal, and user information. For example, the sensing unit 140 may include a proximity sensor 141, an illumination sensor 142, a touch sensor, an acceleration sensor, a magnetic sensor, A G-sensor, a gyroscope sensor, a motion sensor, an RGB sensor, an infrared sensor, a finger scan sensor, an ultrasonic sensor, A microphone 226, a battery gauge, an environmental sensor (for example, a barometer, a hygrometer, a thermometer, a radiation detection sensor, A thermal sensor, a gas sensor, etc.), a chemical sensor (e.g., an electronic nose, a healthcare sensor, a biometric sensor, etc.). Meanwhile, the mobile terminal disclosed in the present specification can combine and utilize information sensed by at least two of the sensors.

The output unit 150 includes at least one of a display unit 151, an acoustic output unit 152, a haptic tip module 153, and a light output unit 154 to generate an output related to visual, auditory, can do. The display unit 151 may have a mutual layer structure with the touch sensor or may be integrally formed to realize a touch screen. The touch screen may function as a user input unit 123 that provides an input interface between the mobile terminal 100 and a user and may provide an output interface between the mobile terminal 100 and a user.

The interface unit 160 serves as a path to various types of external devices connected to the mobile terminal 100. The interface unit 160 is connected to a device having a wired / wireless headset port, an external charger port, a wired / wireless data port, a memory card port, And may include at least one of a port, an audio I / O port, a video I / O port, and an earphone port. In the mobile terminal 100, corresponding to the connection of the external device to the interface unit 160, it is possible to perform appropriate control related to the connected external device.

In addition, the memory 170 stores data supporting various functions of the mobile terminal 100. The memory 170 may store a plurality of application programs or applications running on the mobile terminal 100, data for operation of the mobile terminal 100, and commands. At least some of these applications may be downloaded from an external server via wireless communication. Also, at least a part of these application programs may exist on the mobile terminal 100 from the time of shipment for the basic functions (e.g., telephone call receiving function, message receiving function, and calling function) of the mobile terminal 100. Meanwhile, the application program may be stored in the memory 170, installed on the mobile terminal 100, and may be operated by the control unit 180 to perform the operation (or function) of the mobile terminal.

In addition to the operations related to the application program, the control unit 180 typically controls the overall operation of the mobile terminal 100. The control unit 180 may process or process signals, data, information, and the like input or output through the above-mentioned components, or may drive an application program stored in the memory 170 to provide or process appropriate information or functions to the user.

In addition, the controller 180 may control at least some of the components illustrated in FIG. 1A in order to drive an application program stored in the memory 170. FIG. In addition, the controller 180 may operate at least two of the components included in the mobile terminal 100 in combination with each other for driving the application program.

The power supply unit 190 receives external power and internal power under the control of the controller 180 and supplies power to the components included in the mobile terminal 100. The power supply unit 190 includes a battery, which may be an internal battery or a replaceable battery.

At least some of the components may operate in cooperation with one another to implement a method of operation, control, or control of a mobile terminal according to various embodiments described below. In addition, the operation, control, or control method of the mobile terminal may be implemented on the mobile terminal by driving at least one application program stored in the memory 170. [

Referring to FIGS. 1B and 1C, the disclosed mobile terminal 100 includes a bar-shaped terminal body. However, the present invention is not limited thereto and can be applied to various structures such as a folder type, a flip type, a slide type, a swing type, and a swivel type in which a watch type, a clip type, a glass type or two or more bodies are relatively movably coupled . A description of a particular type of mobile terminal, although relevant to a particular type of mobile terminal, is generally applicable to other types of mobile terminals.

Here, the terminal body can be understood as a concept of referring to the mobile terminal 100 as at least one aggregate.

The mobile terminal 100 includes a case (for example, a frame, a housing, a cover, and the like) that forms an appearance. As shown, the mobile terminal 100 may include a front case 101 and a rear case 102. Various electronic components are disposed in the inner space formed by the combination of the front case 101 and the rear case 102. At least one middle case may be additionally disposed between the front case 101 and the rear case 102.

A display unit 151 is disposed on a front surface of the terminal body to output information. The window 151a of the display unit 151 may be mounted on the front case 101 to form a front surface of the terminal body together with the front case 101. [

In some cases, electronic components may also be mounted on the rear case 102. Electronic parts that can be mounted on the rear case 102 include detachable batteries, an identification module, a memory card, and the like. In this case, a rear cover 103 for covering the mounted electronic components can be detachably coupled to the rear case 102. Therefore, when the rear cover 103 is separated from the rear case 102, the electronic parts mounted on the rear case 102 are exposed to the outside.

As shown, when the rear cover 103 is coupled to the rear case 102, a side portion of the rear case 102 can be exposed. In some cases, the rear case 102 may be completely covered by the rear cover 103 during the engagement. Meanwhile, the rear cover 103 may be provided with an opening for exposing the camera 121b and the sound output unit 152b to the outside.

These cases 101, 102, and 103 may be formed by injection molding of synthetic resin or may be formed of metal such as stainless steel (STS), aluminum (Al), titanium (Ti), or the like.

The mobile terminal 100 may be configured such that one case provides the internal space, unlike the above example in which a plurality of cases provide an internal space for accommodating various electronic components. In this case, a unibody mobile terminal 100 in which synthetic resin or metal is connected from the side to the rear side can be realized.

Meanwhile, the mobile terminal 100 may include a waterproof unit (not shown) for preventing water from penetrating into the terminal body. For example, the waterproof portion is provided between the window 151a and the front case 101, between the front case 101 and the rear case 102, or between the rear case 102 and the rear cover 103, And a waterproof member for sealing the inside space of the oven.

The mobile terminal 100 is provided with a display unit 151, first and second sound output units 152a and 152b, a proximity sensor 141, an illuminance sensor 142, a light output unit 154, Cameras 121a and 121b, first and second operation units 123a and 123b, a microphone 122, an interface unit 160, and the like.

1B and 1C, a display unit 151, a first sound output unit 152a, a proximity sensor 141, an illuminance sensor 142, an optical output unit (not shown) A second operation unit 123b, a microphone 122 and an interface unit 160 are disposed on a side surface of the terminal body, And a mobile terminal 100 having a second sound output unit 152b and a second camera 121b disposed on a rear surface thereof.

However, these configurations are not limited to this arrangement. These configurations may be excluded or replaced as needed, or placed on different planes. For example, the first operation unit 123a may not be provided on the front surface of the terminal body, and the second sound output unit 152b may be provided on the side surface of the terminal body rather than the rear surface of the terminal body.

The display unit 151 displays (outputs) information processed by the mobile terminal 100. For example, the display unit 151 may display execution screen information of an application program driven by the mobile terminal 100 or UI (User Interface) and GUI (Graphic User Interface) information according to the execution screen information .

The display unit 151 may be a liquid crystal display (LCD), a thin film transistor-liquid crystal display (TFT LCD), an organic light-emitting diode (OLED), a flexible display display, a 3D display, and an e-ink display.

In addition, the display unit 151 may exist in two or more depending on the embodiment of the mobile terminal 100. In this case, the mobile terminal 100 may be provided with a plurality of display portions spaced apart from each other or disposed integrally with one another, or may be disposed on different surfaces, respectively.

The display unit 151 may include a touch sensor that senses a touch with respect to the display unit 151 so that a control command can be received by a touch method. When a touch is made to the display unit 151, the touch sensor senses the touch, and the control unit 180 generates a control command corresponding to the touch based on the touch. The content input by the touch method may be a letter or a number, an instruction in various modes, a menu item which can be designated, and the like.

The touch sensor may be a film having a touch pattern and disposed between the window 151a and a display (not shown) on the rear surface of the window 151a, or may be a metal wire . Alternatively, the touch sensor may be formed integrally with the display. For example, the touch sensor may be disposed on a substrate of the display or inside the display.

In this way, the display unit 151 can form a touch screen together with the touch sensor. In this case, the touch screen can function as a user input unit 123 (see FIG. 1A). In some cases, the touch screen may replace at least some functions of the first operation unit 123a.

The first sound output unit 152a may be implemented as a receiver for transmitting a call sound to a user's ear and the second sound output unit 152b may be implemented as a loud speaker for outputting various alarm sounds or multimedia playback sounds. ). ≪ / RTI >

The window 151a of the display unit 151 may be provided with an acoustic hole for emitting the sound generated from the first acoustic output unit 152a. However, the present invention is not limited to this, and the sound may be configured to be emitted along an assembly gap (for example, a gap between the window 151a and the front case 101) between the structures. In this case, the appearance of the mobile terminal 100 can be simplified because the holes that are formed independently for the apparent acoustic output are hidden or hidden.

The optical output unit 154 is configured to output light for notifying the occurrence of an event. Examples of the event include a message reception, a call signal reception, a missed call, an alarm, a schedule notification, an email reception, and reception of information through an application. The control unit 180 may control the light output unit 154 to terminate the light output when the event confirmation of the user is detected.

The first camera 121a processes an image frame of a still image or a moving image obtained by the image sensor in the photographing mode or the video communication mode. The processed image frame can be displayed on the display unit 151 and can be stored in the memory 170. [

The first and second operation units 123a and 123b may be collectively referred to as a manipulating portion as an example of a user input unit 123 operated to receive a command for controlling the operation of the mobile terminal 100 have. The first and second operation units 123a and 123b can be employed in any manner as long as the user is in a tactile manner such as touch, push, scroll, or the like. In addition, the first and second operation units 123a and 123b may be employed in a manner that the user operates the apparatus without touching the user through a proximity touch, a hovering touch, or the like.

In this figure, the first operation unit 123a is a touch key, but the present invention is not limited thereto. For example, the first operation unit 123a may be a mechanical key, or a combination of a touch key and a touch key.

The contents input by the first and second operation units 123a and 123b can be variously set. For example, the first operation unit 123a receives a command such as a menu, a home key, a cancellation, a search, and the like, and the second operation unit 123b receives a command from the first or second sound output unit 152a or 152b The size of the sound, and the change of the display unit 151 to the touch recognition mode.

On the other hand, a rear input unit (not shown) may be provided on the rear surface of the terminal body as another example of the user input unit 123. The rear input unit is operated to receive a command for controlling the operation of the mobile terminal 100, and input contents may be variously set. For example, commands such as power on / off, start, end, scrolling, and the like, the size adjustment of the sound output from the first and second sound output units 152a and 152b, And the like can be inputted. The rear input unit may be implemented as a touch input, a push input, or a combination thereof.

The rear input unit may be disposed so as to overlap with the front display unit 151 in the thickness direction of the terminal body. For example, the rear input unit may be disposed at the rear upper end of the terminal body such that when the user holds the terminal body with one hand, the rear input unit can be easily operated using the index finger. However, the present invention is not limited thereto, and the position of the rear input unit may be changed.

When a rear input unit is provided on the rear surface of the terminal body, a new type of user interface using the rear input unit can be realized. When the first operation unit 123a is not disposed on the front surface of the terminal body in place of at least a part of the functions of the first operation unit 123a provided on the front surface of the terminal body, The display unit 151 may be configured as a larger screen.

Meanwhile, the mobile terminal 100 may be provided with a fingerprint recognition sensor for recognizing the fingerprint of the user, and the controller 180 may use the fingerprint information sensed through the fingerprint recognition sensor as authentication means. The fingerprint recognition sensor may be embedded in the display unit 151 or the user input unit 123.

The microphone 122 is configured to receive the user's voice, other sounds, and the like. The microphone 122 may be provided at a plurality of locations to receive stereophonic sound.

The interface unit 160 is a path through which the mobile terminal 100 can be connected to an external device. For example, the interface unit 160 may include a connection terminal for connection with another device (for example, an earphone or an external speaker), a port for short-range communication (for example, an infrared port (IrDA Port), a Bluetooth port A wireless LAN port, or the like), or a power supply terminal for supplying power to the mobile terminal 100. The interface unit 160 may be implemented as a socket for receiving an external card such as a SIM (Subscriber Identification Module) or a UIM (User Identity Module) or a memory card for storing information.

And a second camera 121b may be disposed on a rear surface of the terminal body. In this case, the second camera 121b has a photographing direction which is substantially opposite to that of the first camera 121a.

The second camera 121b may include a plurality of lenses arranged along at least one line. The plurality of lenses may be arranged in a matrix form. Such a camera can be named an 'array camera'. When the second camera 121b is configured as an array camera, images can be taken in various ways using a plurality of lenses, and a better quality image can be obtained.

The flash 124 may be disposed adjacent to the second camera 121b. The flash 124 shines light toward the subject when the subject is photographed by the second camera 121b.

And a second sound output unit 152b may be additionally disposed in the terminal body. The second sound output unit 152b may implement a stereo function together with the first sound output unit 152a and may be used for implementing a speakerphone mode in a call.

The terminal body may be provided with at least one antenna for wireless communication. The antenna may be embedded in the terminal body or formed in the case. For example, an antenna constituting a part of the broadcast receiving module 111 (see FIG. 1A) may be configured to be able to be drawn out from the terminal body. Alternatively, the antenna may be formed in a film type and attached to the inner surface of the rear cover 103, or a case including a conductive material may be configured to function as an antenna.

The terminal body is provided with a power supply unit 190 (see FIG. 1A) for supplying power to the mobile terminal 100. The power supply unit 190 may include a battery 191 built in the terminal body or detachable from the outside of the terminal body.

The battery 191 may be configured to receive power through a power cable connected to the interface unit 160. In addition, the battery 191 may be configured to be wirelessly chargeable through a wireless charger. The wireless charging may be implemented by a magnetic induction method or a resonance method (magnetic resonance method).

The rear cover 103 is configured to be coupled to the rear case 102 so as to cover the battery 191 to restrict the release of the battery 191 and to protect the battery 191 from external impact and foreign matter . When the battery 191 is detachably attached to the terminal body, the rear cover 103 may be detachably coupled to the rear case 102.

The mobile terminal 100 may be provided with an accessory that protects the appearance or supports or expands the function of the mobile terminal 100. [ One example of such an accessory is a cover or pouch that covers or accommodates at least one side of the mobile terminal 100. [ The cover or pouch may be configured to interlock with the display unit 151 to expand the function of the mobile terminal 100. Another example of an accessory is a touch pen for supplementing or extending a touch input to the touch screen.

In the foregoing, the configuration of the mobile terminal 100 according to the present invention has been described with reference to FIGS. 1A to 1C. Hereinafter, an antenna apparatus for a mobile terminal capable of improving isolation between antenna elements within a limited mounting space of a terminal will be described in detail according to a first embodiment of the present invention.

First Embodiment

2 is a view showing the structure of an antenna device for a mobile terminal according to a first embodiment of the present invention.

Referring to FIG. 2, the antenna device 200 according to the first embodiment of the present invention includes a printed circuit board 240, a first antenna element 210 located on one side of the printed circuit board 240, A second antenna element 220 located on the other side of the circuit board 240, a coupling element 230 spaced apart from the first and second antenna elements 210 and 220 by a predetermined distance, A variable circuit element 235 connected between the ring element 230 and the grounding portion of the printed circuit board 240 to form a coupling element 230 and a band stop filter, And a dielectric member 250 for supporting the antenna elements 210 and 220 and the coupling element 230.

The printed circuit board 240 includes power feeders 214 and 224 for mounting electronic components for operating various functions of the mobile terminal 100 and supplying power to the first and second antenna elements 210 and 220, And a grounding portion (not shown) connecting the first and second antenna elements 210 and 220 and the coupling element 230 to the ground. The ground unit may be formed by applying a metal material to one surface of the printed circuit board 240, but is not limited thereto.

The first and second antenna elements 210 and 220 are formed on the dielectric member 250 at one end of the printed circuit board 240 together with the coupling element 230, Symmetrical shape. At this time, any one of a planar inverted F antenna (PIFA), a mono pole antenna, and a slot antenna may be used as the first and second antenna elements 210 and 220 Among them, it is preferable to use a PIFA antenna.

The first antenna element 210 includes a first feeding line 211 connected to the feeding part 214 located in one area of the printed circuit board 240 and a second feeding line 211 connected to the grounding part of the printed circuit board 240 A ground line 212 and a first antenna pattern 213 connected to the first feed line 211 and the first ground line 212 and radiating an RF signal to the outside.

The second antenna element 220 includes a second feed line 212 connected to the feed part 224 located in one region of the printed circuit board 240 and a second feed line 212 connected to the ground of the printed circuit board 240. [ And a second antenna pattern 223 connected to the second feed line 221 and the second ground line 222 and radiating an RF signal to the outside.

The first and second antenna patterns 213 and 223 are formed at 1/4 length of the wavelength? Corresponding to the center frequency of the operating frequency band of each antenna element, and are formed in a three-dimensional structure on the dielectric member 250 do.

More specifically, the first antenna pattern 213 starts from the first feeding line 211 and is bent at least once more, and then two ends 216 and 217 are formed on the upper left surface of the dielectric member 250, And has a shape to be seen. Likewise, the second antenna pattern 223 starts from the second feeding line 221 and is bent at least once more. After that, the two ends 226 and 227 are positioned facing each other on the right upper surface of the dielectric member 250 . At this time, the first and second antenna patterns 213 and 223 are vertically arranged on the different plane from the first and second feed lines 211 and 221 and the first and second ground lines 212 and 222, respectively. It should be apparent to those skilled in the art that the shape of the antenna pattern shown in FIG. 2 is only an embodiment of the present invention, and that the scope of the present invention is not limited.

The first and second antenna elements 210 and 220 formed as described above are individually connected to an external signal circuit through the first and second feed lines 211 and 221 and are supplied with corresponding electrical signals, Or receives different electromagnetic waves from the outside and transmits them to an external signal circuit.

The coupling element 230 is formed on the dielectric member 250 together with the first and second antenna elements 210 and 220 and is spaced apart from the first and second antenna elements 210 and 220 And is connected to the ground of the printed circuit board 240.

The coupling element 230 includes a coupling pattern 231 for generating capacitive coupling and / or inductive coupling between the first and second antenna elements 210 and 220, 240 and a coupling ground line 232 connecting the coupling pattern 231 with each other.

The coupling pattern 231 is disposed in parallel with the first and second antenna patterns 213 and 223 of the first and second antenna elements 210 and 220 and the first and second antenna patterns 213 and 213, 223 to suppress the surface current induced by the first and second antenna patterns 113, 123. At this time, the shape of the coupling pattern 231 is formed in a symmetrical structure of 'T' shape. On the other hand, it will be apparent to those skilled in the art that the shape of the coupling pattern 231 shown in FIG. 2 is only an embodiment of the present invention, and that the scope of the present invention is not limited.

The coupling ground line 232 is arranged in parallel with the first and second ground lines 212 and 222 of the first and second antenna elements 210 and 220 and the coupling pattern 231 and the printed And a band stop filter (hereinafter referred to as 'BSF') is formed by connecting variable circuit elements 253 mounted on the circuit board 240.

The coupling element 230 attenuates the mutual coupling due to the surface current generated in the first and second antenna elements 210 and 220 and transmits the coupling between the first and second antenna elements 210 and 220 It plays a role of improving the isolation degree. That is, the coupling element 230 can be configured to allow the surface current in the form of a closed loop to flow, thereby reducing the surface current formed in the PCB ground, thereby improving the isolation between the antenna elements.

The variable circuit element 235 is connected between the coupling element 230 and the ground of the printed circuit board 240 and implements the characteristics of the BSF filter together with the coupling element 230. At this time, the variable circuit element 235 may be mounted on the printed circuit board 240.

The variable circuit element 235 varies the resonance frequency showing the characteristics of the BSF filter according to a value of an isolation frequency required to eliminate mutual coupling between the antenna elements.

3 is a diagram illustrating the configuration of a variable circuit element included in the antenna device according to the first embodiment of the present invention. As shown in FIG. 3A, the variable circuit device 235 may include a switch 310 and a plurality of fixed capacitors 320. 3 (b), the variable circuit element 235 may be composed of a switch 310 and a plurality of fixed inductors 330. 3 (c) and 3 (d), the variable circuit element 235 may be formed of any one of the variable capacitor 330 and the variable capacitance diode 340. On the other hand, although not shown in the drawings, the variable circuit element 235 may be configured by a combination of a switch and a plurality of fixed capacitors and fixed inductors.

4 is a diagram showing electrical characteristics of a band elimination filter implemented through a coupling element and a variable circuit element. Referring to FIG. 4, the value of S12 indicating the isolation of the S parameters indicates the characteristics of the band elimination filter. As a result, it can be seen that the degree of isolation between the antenna elements is significantly improved in the frequency band in which the value of S11 representing the reflection characteristic is the smallest among the S parameters.

5 is a diagram showing electrical characteristics of a band elimination filter implemented by changing a coupling element and a variable circuit element in a low frequency band or a high frequency band. As shown in FIG. 5 (a), it can be seen that the isolation frequency is changed in accordance with the change of the structure of the coupling element in the low frequency band. Also, as shown in FIG. 5B, it can be seen that the isolation frequency is changed in accordance with the change in the structure of the coupling element in the high frequency band. On the other hand, it is apparent to those skilled in the art that although not shown in the drawing, the value of the resonance frequency (i.e., isolation frequency) showing the characteristics of the BSF filter can be changed by changing the value of the variable circuit element in the low frequency or high frequency band.

The coupling element 230 and the variable circuit element 235 formed in this way can realize the characteristics of the BSF filter between the first and second antenna elements 210 and 220 in the low frequency and high frequency bands, The degree of isolation between the second antenna elements 210 and 220 can be efficiently improved.

2, the antenna device 200 according to the first embodiment of the present invention includes first and second antenna elements 210 and 220 that vary the resonance frequency (i.e., operating frequency) of the first and second antenna elements 210 and 220, Two frequency tunable elements 215 and 225, respectively.

The first frequency tunable device 215 is connected in series between the first ground line 212 of the first antenna element 210 and the ground of the printed circuit board 240, The resonant frequency is variable. The first variable frequency element 215 is connected between the first feeding line 211 of the first antenna element 210 and the feeding part 214 of the printed circuit board 240 in parallel So that the resonance frequency of the first antenna element 210 can be varied.

The second frequency tunable device 225 is connected in parallel between the second feed line 221 of the second antenna element 220 and the feeder 224 of the printed circuit board 240, 220). Although not shown in the drawing, the second frequency variable element 225 is connected in series between the second ground line 222 of the second antenna element 220 and the grounding portion of the printed circuit board 240, The resonance frequency of the second antenna element 220 can be varied.

6 is a diagram illustrating a configuration of a variable frequency element included in the antenna apparatus according to the first embodiment of the present invention. As shown in FIG. 6A, the first and second frequency tunable devices 215 and 225 may be composed of a switch 610 and a plurality of fixed capacitors 620. 6 (b), the first and second variable frequency devices 215 and 225 may be composed of a switch 610 and a plurality of fixed inductors 630. 6 and 7, the first and second frequency variable circuits 215 and 225 may be formed of any one of the variable capacitor 630 and the variable capacitance diode 640, have. Also, although not shown in the figure, the first and second frequency variable elements 215 and 225 may be configured by a combination of a switch and a plurality of fixed capacitors and fixed inductors.

The first and second variable tuning elements 215 and 225 are designed so that the resonance frequencies of the respective antennas are set so that the resonance frequencies of the first and second antenna elements 210 and 220 do not overlap with each other when the Muti Co- Thereby maximizing the degree of isolation between the antenna elements.

Table 1 below is a scenario for varying the resonance frequencies of the first and second antenna elements in order to maximize the degree of isolation between the antenna elements in a DSDA (Dual Sim Dual Active) communication system supporting Muti Co-band.

Communication
system action
frequency send/
reception antenna
Kinds Antenna 1
Tuner_0 Antenna 1
Tuner_1 Antenna 2
Tuner_0 Antenna 2
Tuner_1



GSM



850 TX ANT1 0 One 5 State 5 State RX ANT1 0 One 5 State 5 State
900 TX ANT1 One 0 5 State 5 State RX ANT1 One 0 5 State 5 State
1800 TX ANT1 One 0 5 State 5 State RX ANT1 One 0 5 State 5 State
1900 TX ANT1 One 0 5 State 5 State RX ANT1 One 0 5 State 5 State



DSDA
GSM




850 TX ANT2 0 One One 0 RX ANT2 0 One One 0
900 TX ANT2 One 0 0 One RX ANT2 One 0 0 One
1800 TX ANT2 One 0 One 0 RX ANT2 One 0 One 0 CNCC
DCS TX ANT2 One 0 One 0 RX ANT2 One 0 One 0
1900 TX ANT2 One 0 One 0 RX ANT2 One 0 One 0

Referring to Table 1, in the DSDA communication system, the values of the first and second frequency variable elements 215 and 225 are changed according to the control command for each operating frequency, The resonant frequency is variable. Accordingly, the resonance frequencies of the first and second antenna elements 210 and 220 operating in the same frequency band are adjusted so as not to overlap with each other, thereby maximizing the degree of isolation between the antenna elements.

As described above, the antenna device according to the first embodiment of the present invention can improve the isolation between the antenna elements by implementing the characteristics of the band elimination filter between the first and second antenna elements. In addition, when the two antenna elements adjacent to each other operate in the same frequency band, the antenna device can vary the resonance frequency of the first and second antenna elements, thereby maximizing the degree of isolation between the antenna elements.

Hereinafter, according to a second embodiment of the present invention, an antenna device for a mobile terminal capable of improving isolation between antenna elements in an antenna structure including a slot antenna and a PIFA antenna (or monopole antenna) This will be described in detail.

Second Embodiment

7 is a view schematically showing a structure of a conventional antenna device for a mobile terminal.

Referring to FIG. 7, the conventional antenna apparatus 700 includes a slot antenna 710 located at the lower left of the mobile terminal and a PIFA antenna 720 located at the lower right of the mobile terminal.

The slot antenna 710 includes a metal frame 711 forming an upper portion of a slot 712, a printed circuit board 713 forming a lower portion of the slot 712, A first feeding part 715 positioned at a right upper end of the slot 712 to supply electric power to the corresponding slot 712, And a first feeding line 714 for vertically connecting the first feeding part 715 with the right area of the printed circuit board 713.

The PIFA antenna 720 includes a second feeding part 723 located in one area of a printed circuit board (not shown) and supplying power to the antenna, a second feeding line (not shown) connected to the second feeding part 723, And an antenna pattern 721 connected to the second feeder line 722 and radiating an RF signal to the outside.

The first feeder 715 and the first feeder line 714 of the slot antenna 710 are disposed adjacent to the PIFA antenna 720 so as to mutually couple, There is a problem in that the isolation degree between the antenna elements is rapidly deteriorated. Therefore, we propose an antenna device with a new structure that can improve the isolation between antenna elements by changing the structure of the slot antenna and supporting Multi Co-band.

FIG. 8A is a schematic view of a structure of an antenna device for a mobile terminal according to a second embodiment of the present invention, and FIG. 8B is a view showing a detailed structure of a printed circuit board Fig.

8A, the antenna apparatus 800 according to the second embodiment of the present invention includes a slot antenna 810 located at the lower left of the mobile terminal, a PIFA antenna 820 located at the lower right of the mobile terminal, .

The slot antenna 810 includes a metal frame 811 forming an upper portion of the slot 812, a printed circuit board 801 forming a lower portion of the slot 812, a metal frame 811 and a printed circuit board 801, A first feeding part 818 located at a left upper end of the slot 812 to supply electric power, a first feeding part 818 for supplying power to the first feeding part 818, A slot feed line 814 extending in the horizontal direction for connecting the first feed line 813 to the ground layer 817 of the printed circuit board 801, A matching circuit 815 for forming an antenna resonance together with the slot feed line 814, and a contact member 819 for forming an antenna resonance in combination with a radiation pattern on the antenna carrier.

The printed circuit board 819 includes a ground layer 817 forming a slot 812 by ground bonding with the metal frame 811 and a plurality of vias 810 connecting the ground layer 817 and the slot feed line 814 816). A slot 812 is formed through the metal frame 811, the ground layer 817 and the via 816, and the gap of the formed slot corresponds to the thickness of the via 816. Therefore, the resonance characteristics of the slot antenna 810 vary depending on the thickness of the via 816.

The slot antenna 810 having such a structure can form various resonance frequencies through the slot feed line 814, the matching circuit 815, and the contact member 819. At this time, the matching circuit 815 may be composed of a switch, a fixed capacitor, a fixed inductor, a variable capacitor, a variable capacitance diode, or a combination thereof, and the value may be varied according to a value of a resonance frequency required by the terminal system .

The PIFA antenna 820 includes a second feeding part 823 located in one area of a printed circuit board (not shown) and supplying power to the antenna, a second feeding line 823 connected to the second feeding part 823, And an antenna pattern 821 connected to the second feeding line 822 and radiating an RF signal to the outside.

The first feeding part 818 of the slot antenna 810 and the second feeding part 823 of the PIFA antenna 820 are formed so as to be arranged side by side on both sides of the lower end of the terminal, do. That is, the distance between the first feeding part 818 of the slot antenna 810 and the second feeding part 823 of the PIFA antenna 820 is arranged as far as possible in order to minimize mutual interference between the antenna elements.

The antenna device 800 having such a structure can minimize the mutual interference due to the surface current induced in each antenna element when the multi-co-band is supported, thereby improving the isolation characteristic between the antenna elements.

9A shows electrical characteristics of an antenna device for a conventional mobile terminal, and FIG. 9B shows electrical characteristics of an antenna device according to a second embodiment of the present invention.

9A and 9B, when a multi-co-band (for example, 900 MHz, 1.9 GHz) is supported, the conventional antenna apparatus 700 has an isolation characteristic of -10 dB in the 1.9 GHz band S12), while the antenna device 800 according to the present invention exhibits an isolation characteristic of -18 dB in the 1.9 GHz band. Accordingly, it can be seen that in the high frequency band, the isolation characteristic of about 8 dB is improved through the change of the structure of the slot antenna 810 and the insertion of the matching circuit 815.

Meanwhile, in the present embodiment, a PIFA antenna 820 is installed at the lower right of the mobile terminal. However, the PIFA antenna 820 may be replaced with a monopole antenna or slot antenna instead of the PIFA antenna 820.

10 (a), a slot antenna 1010 may be installed at the lower left of the mobile terminal, and a monopole antenna 1030 may be installed at the lower right of the mobile terminal. The feeding part 1020 of the slot antenna 1010 and the feeding part 1040 of the monopole antenna 1030 are formed to be arranged side by side on both sides of the lower end of the mobile terminal.

10B, a first slot antenna 1050 may be installed on the lower left side of the mobile terminal, and a second slot antenna 1070 may be provided on the lower right side of the mobile terminal. The feeding part 1060 of the first slot antenna 1050 and the feeding part 1080 of the second slot antenna 1070 are formed to be arranged side by side on both sides of the lower end of the mobile terminal.

As described above, the antenna device for a mobile terminal according to the second embodiment of the present invention improves the isolation characteristics between the antenna elements by changing the structure of the slot antenna and inserting the matching circuit when the multi co- can do.

The present invention described above can be implemented as computer readable codes on a medium on which a program is recorded. The computer readable medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of the computer readable medium include a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, , And may also be implemented in the form of a carrier wave (e.g., transmission over the Internet). In addition, the computer may include a control unit 180 of the terminal. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

200: antenna device 210: first antenna element
220: second antenna element 230: coupling element
235: variable circuit element 240: printed circuit board
250: dielectric member

Claims (5)

Printed circuit board;
A first feed line connected to a feeding part of the printed circuit board, a first ground line connected to a ground part of the printed circuit board, and a first antenna pattern radiating a first RF signal, ;
A second feed line connected to a feeding part of the printed circuit board, a second ground line connected to a ground part of the printed circuit board, and a second antenna pattern radiating a second RF signal, ;
A coupling element disposed at a predetermined distance from the first and second antennas; And
And a variable circuit element connected between the coupling element and the ground to form the coupling element and a band stop filter. The method according to claim 1,
Wherein the first and second antenna elements are formed symmetrically with respect to each other. The method according to claim 1,
And a first frequency variable circuit connected in series between the first ground line and the ground unit and varying a resonance frequency of the first antenna element. The method according to claim 1,
And a second frequency variable circuit connected in parallel between the second feeder line and the feeder to vary the resonant frequency of the second antenna element. The method according to claim 1,
Wherein the first and second antenna elements are Planar Inverted-F Antenna (PIFA).

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