KR102088825B1 - Antenna device of a mobile terminal - Google Patents

Abstract

The present invention relates to an antenna device for a mobile terminal, a printed circuit board; A first antenna element including a first feeding line connected to a feeding portion of the printed circuit board, a first grounding line connected to a ground portion of the printed circuit board, and a first antenna pattern emitting a first RF signal ; A second antenna element including a second feeding line connected to a feeding portion of the printed circuit board, a second grounding line connected to a ground portion of the printed circuit board, and a second antenna pattern emitting 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 ground part to form a band cancellation filter with the coupling element.

Description

Antenna device for mobile terminals {ANTENNA DEVICE OF A MOBILE TERMINAL}

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.

Terminals can be divided into mobile terminals (mobile / portable terminals) and stationary terminals depending on whether they are mobile. Again, the mobile terminal may be divided into a handheld terminal and a vehicle mounted terminal according to whether the user can directly carry it.

The functions of mobile terminals are diversifying. For example, data and voice communication, taking a picture and video with a camera, recording a voice, playing a music file through a speaker system, and outputting an image or video to a display unit. In some terminals, an electronic game play function is added or a multimedia player function is performed. In particular, recent mobile terminals can receive multicast signals that provide visual content such as broadcast and video or television programs.

As the function of the terminal is diversified, for example, a multimedia player type having multiple functions such as taking a picture or a video, playing a music or video file, receiving a game, or broadcasting, etc. Is being implemented as To support and increase the function of such a terminal, it may be considered to improve the structural part and / or software part of the terminal.

On the other hand, recently, in accordance with the demand for miniaturization and slimness of a mobile terminal, a built-in antenna considering the aesthetics of the terminal is preferred. In addition, in accordance with the demand for high-speed multimedia services, the increase in communication capacity in the mobile communication system continues to accelerate. Accordingly, there is a growing interest in antenna technology for a broadband mobile communication system that can satisfy both the miniaturization of the antenna and the ever-increasing communication capacity and reliability of communication.

According to this trend, the proposed technology is an antenna technology using MIMO (Multi-Input Multi-Output) or diversity, which has recently been spotlighted. First, a method using MIMO is a method of multi-input / multi-output that increases the number of antennas of a base station and a mobile terminal to two or more, and transmits data through multiple paths, and detects a signal received by each path at a receiving end. to be. Next, the method using diversity is a method of receiving signal propagation using two or more antennas and synthesizing the outputs to detect the received signal. The MIMO / diversity antenna to which this technology is applied can increase the reliability of transmitted data, and has the advantage of overcoming the limitation of the amount of mobile communication transmission due to data communication expansion.

However, when such a mito / diversity antenna is used in a mobile terminal, there is a problem in that isolation occurs rapidly due to mutual coupling between antennas due to spatial limitations of the mobile terminal.

In order to solve this problem, a method of reducing the distance between antennas by λ / 2 or more (where λ is the wavelength of the radio waves emitted by the antenna) can be considered. However, in the built-in antenna, since the mounting space where the antenna is installed is limited, the above-described problem cannot be solved by a method of separating the distance between the antennas.

As another method, prior documents suggesting a structure for improving the isolation between the MIMO / diversity antennas include the US registered patent (US 7,688,273) and the Korean published patent (No. 2013-0023669).

In the US registered patent (US 7,688,273), a decoupling network (or suspend line, 210) is connected between λ / 2 monopole antenna elements 202 and 204 to reduce the surface current flowing to the PCB ground. It is a structure that improves the antenna isolation. However, in the case of the U.S. registered patent, there is only one resonant frequency having good isolation (S12) characteristics, and in the high frequency band of 1 GHz or higher, there is a problem of having poor isolation characteristics of S12: -2dB to -3dB. .

In addition, in Korean published patent (No. 2013-0023669), the current conversion element 130 is connected between two planar inverse F antennas (PIFAs) 110 and 120 to affect the other antenna. Note is a structure that improves the isolation of the antenna by reducing the surface current. However, in the case of Korean published patents, although good isolation characteristics are shown in a high frequency band of 1 GHz or more, improvement in isolation characteristics is not significant in a low frequency band of 1 GHz or less.

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

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

Another object is to provide an antenna device capable of improving isolation between antenna elements by varying 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 to achieve the above or other object, a printed circuit board; A first antenna element including a first feeding line connected to a feeding portion of the printed circuit board, a first grounding line connected to a ground portion of the printed circuit board, and a first antenna pattern emitting a first RF signal ; A second antenna element including a second feeding line connected to a feeding portion of the printed circuit board, a second grounding line connected to a ground portion of the printed circuit board, and a second antenna pattern emitting 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 ground part to form a band cancellation filter with the coupling element.

The effects of the mobile terminal and its control method according to the present invention are as follows.

According to at least one of the embodiments of the present invention, in a multi-co-band system in which at least two antenna elements are operable in the same frequency band, it is possible to improve the mountability of antenna elements by changing the structure of the antenna and inserting circuits. In addition, there is an advantage that can improve the isolation between each antenna element.

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

1A is a block diagram for explaining a mobile terminal related to the present invention;
1B and 1C are conceptual views of an example of a mobile terminal related to the present invention viewed from different directions;
2 is a view showing the 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 provided in the antenna device according to the first embodiment of the present invention;
4 is a view showing electrical characteristics of a band cancellation filter implemented through a coupling element and a variable circuit element;
5 is a view showing the electrical characteristics of a band cancellation filter implemented by changing a coupling element and a variable circuit element in a low frequency or high frequency band;
6 is a diagram illustrating a configuration of a frequency variable element provided in the antenna device according to the first embodiment of the present invention;
7 is a view schematically showing the 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 diagram 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 disclosure will be described in detail with reference to the accompanying drawings, and the same or similar components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. The suffixes "module" and "unit" for components used in the following description are given or mixed in consideration of ease of specification, and do not have distinct meanings or roles. In addition, in describing the embodiments disclosed in the present specification, when it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed herein, detailed descriptions thereof will be omitted. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and the technical spirit disclosed in the specification is not limited by the accompanying drawings, and all modifications included in the spirit and technical scope of the present invention , It should be understood to include equivalents or substitutes.

Mobile terminals described herein include mobile phones, smart phones, laptop computers, digital broadcasting terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), navigation, and slate PCs. , Tablet PC (tablet PC), ultrabook (ultrabook), wearable device (wearable device, for example, a watch-type terminal (smartwatch), glass-type terminal (smart glass), HMD (head mounted display), etc. may be included have.

However, the configuration according to the embodiment described in the present specification can be easily recognized by those skilled in the art that it can be applied to a fixed terminal such as a digital TV, a desktop computer, and a digital signage, except when applicable only to a mobile terminal. will be.

1A to 1C, FIG. 1A is a block diagram illustrating a mobile terminal related to the present invention, and FIGS. 1B and 1C are conceptual views of an example of a mobile terminal related to the present invention viewed from 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 a power supply unit 190 ) And the like. The components shown in FIG. 1A are not essential for implementing a mobile terminal, so the mobile terminal described herein may have more or fewer components than those listed above.

More specifically, the wireless communication unit 110 among the components, between the mobile terminal 100 and the wireless communication system, between the mobile terminal 100 and another mobile terminal 100, or the mobile terminal 100 and an external server It may include one or more modules that enable wireless communication between. Also, the wireless communication unit 110 may include one or more modules 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-range communication module 114, and a location information module 115. .

The input unit 120 may include a camera 121 for inputting a video signal or a video input unit, a microphone for inputting an audio signal (microphone 122), or an audio input unit, a user input unit 123 for receiving information from a user, for example , A touch key, a push 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 one or more sensors 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 includes a proximity sensor 141, an illumination sensor 142, a touch sensor, an acceleration sensor, a magnetic sensor, and gravity G-sensor, gyroscope sensor, motion sensor, RGB sensor, infrared sensor (IR sensor), fingerprint scan sensor, ultrasonic sensor , Optical sensor (e.g., camera (see 121)), microphone (see 122, battery), battery gauge, environmental sensor (e.g. barometer, hygrometer, thermometer, radioactivity detection sensor, Thermal sensing sensor, gas sensing sensor, etc.), chemical sensors (eg, electronic nose, health care sensor, biometric sensor, etc.). Meanwhile, the mobile terminal disclosed in this specification may combine and use information sensed by at least two or more of these sensors.

The output unit 150 is for generating output related to vision, hearing, or tactile sense, and includes at least one of a display unit 151, an audio output unit 152, a hap tip module 153, and an optical output unit 154 can do. The display unit 151 may form a mutual layer structure with the touch sensor or may be integrally formed, thereby realizing 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 the user, and at the same time, provide an output interface between the mobile terminal 100 and the user.

The interface unit 160 serves as a passage with various types of external devices connected to the mobile terminal 100. The interface unit 160 connects a device equipped with a wired / wireless headset port, an external charger port, a wired / wireless data port, a memory card port, and an identification module. It may include at least one of a port, an audio input / output (I / O) port, a video input / output (I / O) port, and an earphone port. In the mobile terminal 100, in response to an external device being connected to the interface unit 160, appropriate control related to the connected external device may be performed.

Also, the memory 170 stores data supporting various functions of the mobile terminal 100. The memory 170 may store a number of application programs (application programs) that are driven in the mobile terminal 100, data for operation of the mobile terminal 100, and instructions. At least some of these applications may be downloaded from external servers via wireless communication. In addition, at least some of these application programs may exist on the mobile terminal 100 from the time of shipment for basic functions of the mobile terminal 100 (for example, an incoming call, an outgoing function, a message reception, and an outgoing function). Meanwhile, the application program may be stored in the memory 170 and installed on the mobile terminal 100 to be driven by the controller 180 to perform an operation (or function) of the mobile terminal.

The controller 180 controls the overall operation of the mobile terminal 100 in addition to the operations related to the application program. The controller 180 may provide or process appropriate information or functions to the user by processing signals, data, information, etc. input or output through the above-described components or by driving an application program stored in the memory 170.

In addition, the controller 180 may control at least some of the components discussed with reference to FIG. 1A to drive an application program stored in the memory 170. Furthermore, the controller 180 may operate by combining at least two or more of the components included in the mobile terminal 100 for driving the application program.

Under the control of the controller 180, the power supply unit 190 receives external power and internal power to supply power to each component included in the mobile terminal 100. The power supply unit 190 includes a battery, and the battery may be a built-in battery or a replaceable battery.

At least some of the components may operate in cooperation with each other to implement an operation, control, or control method of a mobile terminal according to various embodiments described below. Also, 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.

1B and 1C, the disclosed mobile terminal 100 has a bar-shaped terminal body. However, the present invention is not limited thereto and may be applied to various structures such as a watch type, a clip type, a glass type, or a folder type, a flip type, a slide type, a swing type, a swivel type, and two or more bodies which are coupled to be movable relative to each other. . It will be related to a specific type of mobile terminal, but the description of a specific type of mobile terminal can be generally applied to other types of mobile terminals.

Here, the terminal body may 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, etc.) forming an exterior. As illustrated, 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.

The display unit 151 is disposed on the front of the terminal body to output information. As illustrated, the window 151a of the display unit 151 is mounted on the front case 101 to form the 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 components that can be mounted on the rear case 102 include a removable battery, an identification module, and a memory card. In this case, the rear case 102 may be detachably coupled to the rear cover 103 for covering the mounted electronic components. Therefore, when the rear cover 103 is separated from the rear case 102, the electronic components 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 part of the side surface of the rear case 102 may be exposed. In some cases, the rear case 102 may be completely covered by the rear cover 103 when the coupling is performed. Meanwhile, an opening for exposing the camera 121b or the sound output unit 152b to the outside may be provided in the rear cover 103.

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

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

On the other hand, the mobile terminal 100 may be provided with a waterproof portion (not shown) to prevent water from entering the terminal body. For example, the waterproof part 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 the combination thereof It may include a waterproof member for sealing the interior space of the city.

The mobile terminal 100 includes 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, the first and second units Cameras 121a and 121b, first and second operation units 123a and 123b, a microphone 122, and an interface unit 160 may be provided.

Hereinafter, as illustrated in FIGS. 1B and 1C, a display unit 151, a first sound output unit 152a, a proximity sensor 141, an illuminance sensor 142, and an optical output unit on the front surface of the terminal body ( 154), the first camera (121a) and the first operation unit (123a) is disposed, the second operation unit (123b), the microphone 122 and the interface unit 160 are disposed on the side of the terminal body, the terminal body The mobile terminal 100 in which the second sound output unit 152b and the second camera 121b are disposed on the rear surface of the mobile terminal 100 will be described as an example.

However, these configurations are not limited to this arrangement. These configurations may be excluded or replaced as necessary, or may be disposed on different sides. For example, the first operation unit 123a may not be provided on the front of the terminal body, and the second sound output unit 152b may be provided on the side of the terminal body rather than the rear 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) or GUI (Graphic User Interface) information according to the execution screen information. .

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

In addition, two or more display units 151 may exist according to the implementation form of the mobile terminal 100. In this case, the plurality of display units may be spaced apart or integrally disposed on one surface of the mobile terminal 100, or may be disposed on different surfaces.

The display unit 151 may include a touch sensor that detects a touch on the display unit 151 so that a control command can be input by a touch method. Using this, when a touch is made to the display unit 151, the touch sensor detects the touch, and the controller 180 can be configured to generate 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, or an instruction or designable menu item in various modes.

On the other hand, the touch sensor is composed of a film having a touch pattern, is disposed between the display (not shown) on the back surface of the window 151a and the window 151a, or a metal wire that is directly patterned on the back surface of the window 151a. It can be. Alternatively, the touch sensor may be formed integrally with the display. For example, the touch sensor may be disposed on the substrate of the display, or may be provided inside the display.

As such, the display unit 151 may form a touch screen together with a touch sensor, and in this case, the touch screen may 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 that delivers a call sound to the user's ear, and the second sound output unit 152b is a loud speaker that outputs various alarm sounds or multimedia playback sounds. ).

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

The light output unit 154 is configured to output light to notify when an event occurs. Examples of the event include message reception, call signal reception, missed calls, alarm, schedule notification, email reception, information reception through an application, and the like. The control unit 180 may control the light output unit 154 to end the output of light when the user's event is detected.

The first camera 121a processes image frames of still images or moving pictures obtained by an image sensor in a shooting mode or a video call mode. The processed image frame may be displayed on the display unit 151, and may be stored in the memory 170.

The first and second operation units 123a and 123b are examples of the user input unit 123 that is operated to receive a command for controlling the operation of the mobile terminal 100, and may also be collectively referred to as a manipulating portion. have. The first and second operation units 123a and 123b may be adopted in any manner as long as the user operates the device while receiving a tactile feeling, such as touch, push, scroll. In addition, the first and second manipulation units 123a and 123b may be employed in such a way that the user operates without a tactile feeling through a proximity touch, a hovering touch, or the like.

In this figure, the first operation unit 123a is illustrated as 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 push key.

Contents input by the first and second operation units 123a and 123b may be variously set. For example, the first operation unit 123a receives commands such as a menu, home key, cancel, search, etc., and the second operation unit 123b is output from the first or second sound output units 152a, 152b. Commands such as adjusting the volume of the sound and switching to the touch recognition mode of the display unit 151 may be received.

Meanwhile, as another example of the user input unit 123 on the rear surface of the terminal body, a rear input unit (not shown) may be provided. The rear input unit is operated to receive a command for controlling the operation of the mobile terminal 100, and the input content may be variously set. For example, commands such as power on / off, start, end, scroll, etc., control the volume of sound output from the first and second sound output units 152a, 152b, and touch recognition mode of the display unit 151. You can receive commands such as conversion of. The rear input unit may be implemented in a form capable of input by touch input, push input, or a combination thereof.

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

When the rear input unit is provided on the rear of the terminal body, a new type of user interface using the rear input unit may be implemented. In addition, when the above-described touch screen or rear input unit replaces at least some functions of the first operation unit 123a provided on the front surface of the terminal body, when the first operation unit 123a is not disposed 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 a user's fingerprint, and the controller 180 may use fingerprint information detected through the fingerprint recognition sensor as an 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 a user's voice, other sounds, and the like. The microphone 122 may be provided at a plurality of locations and configured to receive stereo sound.

The interface unit 160 is a passage through which the mobile terminal 100 can be connected to an external device. For example, the interface unit 160 is a connection terminal for connection with other devices (eg, earphones, external speakers), a port for short-range communication (eg, an infrared port (IrDA Port), a Bluetooth port (Bluetooth) Port, Wireless LAN Port, etc.], or at least one of a power supply terminal for supplying power to the mobile terminal 100. The interface unit 160 may be implemented in the form of a socket that accommodates an external card such as a subscriber identification module (SIM) or a user identity module (UIM) or a memory card for storing information.

A second camera 121b may be disposed on the rear side of the terminal body. In this case, the second camera 121b has a shooting direction substantially opposite to 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 format. Such a camera may be referred to as an 'array camera'. When the second camera 121b is configured as an array camera, images may be captured in a variety of ways using a plurality of lenses, and better quality images may be obtained.

The flash 124 may be disposed adjacent to the second camera 121b. When the flash 124 photographs the subject with the second camera 121b, the light is directed toward the subject.

A second sound output unit 152b may be additionally disposed on the terminal body. The second sound output unit 152b may implement a stereo function together with the first sound output unit 152a, or may be used to implement a speakerphone mode during a call.

The terminal body may be provided with at least one antenna for wireless communication. The antenna may be built in the terminal body or may be formed in the case. For example, an antenna forming part of the broadcast receiving module 111 (see FIG. 1A) may be configured to be pulled out from the terminal body. Alternatively, the antenna may be formed in a film type and attached to the inner side of the rear cover 103, or may be configured such that a case containing a conductive material functions 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 configured to be 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. Also, the battery 191 may be configured to be wirelessly charged through a wireless charger. The wireless charging may be implemented by a magnetic induction method or a resonance method (magnetic resonance method).

Meanwhile, in this drawing, the rear cover 103 is coupled to the rear case 102 so as to cover the battery 191 to limit the detachment of the battery 191, and is configured to protect the battery 191 from external impact and foreign matter. For example. When the battery 191 is configured to be detachably attached to the terminal body, the rear cover 103 may be detachably coupled to the rear case 102.

An accessory that protects the appearance or assists or expands the function of the mobile terminal 100 may be added to the mobile terminal 100. An 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 expand the function of the mobile terminal 100 in conjunction with the display unit 151. Another example of an accessory is a touch pen for assisting or extending a touch input to a touch screen.

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

Embodiment 1

2 is a view showing a 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, and the printing. The second antenna element 220, the first antenna element 210 and the second antenna element 220 located on the other side of the circuit board 240 are spaced apart from each other by a coupling element (coupling element) 230 ), A variable circuit element 235 connected between the coupling element 230 and the ground portion of the printed circuit board 240 to form a coupling element 230 and a band stop filter, 235 And a dielectric member 250 supporting the first antenna element and the second antenna elements 210 and 220 and the coupling element 230.

The printed circuit board 240 is equipped with electronic components for operating various functions of the mobile terminal 100, and a power supply unit 214 for supplying power to the first antenna element 210 and the second antenna element 220, 224) is located, and the first antenna element 210 and the second antenna element 220 and the coupling element 230 is connected to the ground (ground) consisting of a portion (not shown) is located. The ground portion may be formed by coating a metal material on one surface of the printed circuit board 240, but is not limited thereto.

The first antenna element 210 and the second antenna element 220 are formed together with a coupling element 230 on a dielectric member 250 located at one end of the printed circuit board 240, and the coupling element 230 It is made in a symmetrical shape around. At this time, as the first antenna element 210 and the second antenna element 220, any one of a planar inverse F antenna (PIFA), a mono pole antenna, and a slot antenna Can be used, of which it is preferable to use a PIFA antenna.

The first antenna element 210 includes a first feeding line 211 connected to a feeding part 214 located in one region of the printed circuit board 240 and a first connecting part to a ground portion of the printed circuit board 240. It consists of a ground line 212 and a first antenna pattern 213 that is connected to the first feed line 211 and the first ground line 212 to emit an RF signal to the outside.

The second antenna element 220 includes a second power supply line 212 connected to a power supply unit 224 located in an area of the printed circuit board 240 and a second power line connected to the ground portion of the printed circuit board 240. It is made of a second antenna pattern 223 that is connected to the ground line 212 and the second feed line 221 and the second ground line 222 to emit an RF signal to the outside.

The first and second antenna patterns 213 and 223 are formed in a length of 1/4 of the wavelength λ corresponding to the center frequency of the operating frequency band of each antenna element, and 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, and then two ends 216 and 217 face each other on the upper left side of the dielectric member 250. It has the form of looking and looking. Likewise, the second antenna pattern 223 starts from the second feeding line 221 and is bent at least once, and then two ends 226 and 227 are positioned facing each other on the upper right side of the dielectric member 250. It has a form. At this time, the first and second antenna patterns 213 and 223 are vertically disposed on a different plane from the first and second feed lines 211 and 221 and the first and second ground lines 212 and 222. Meanwhile, the shape of the antenna pattern illustrated in FIG. 2 is only an embodiment of the present invention, and it will be apparent to those skilled in the art 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 external signal circuits through the first and second feeding lines 211 and 221 to receive corresponding electric signals, and receive different electromagnetic waves from each other. It transmits or receives different electromagnetic waves from the outside to transmit to the 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 by a predetermined distance. And is connected to the ground of the printed circuit board 240.

The coupling element 230 includes a coupling pattern 231 that generates capacitive coupling and / or inductive coupling between the first and second antenna elements 210 and 220, and a printed circuit board ( 240) and a coupling ground line 232 connecting the coupling pattern 231.

The coupling pattern 231 is disposed in a form parallel to 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 223) and serves to suppress the surface current induced by the first and second antenna patterns 113 and 123. At this time, the shape of the coupling pattern 231 is formed in a symmetrical structure of a 'T' shape. Meanwhile, the shape of the coupling pattern 231 illustrated in FIG. 2 is only an embodiment of the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not limited.

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

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

The variable circuit element 235 is connected between the coupling element 230 and the ground portion 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 the value of the isolation frequency required to remove mutual coupling between antenna elements.

3 is a diagram illustrating a configuration of a variable circuit element provided in the antenna device according to the first embodiment of the present invention. As illustrated in FIG. 3A, the variable circuit element 235 may include a switch 310 and a plurality of fixed capacitors 320. In addition, as illustrated in FIG. 3B, the variable circuit element 235 may include a switch 310 and a plurality of fixed inductors 330. In addition, as illustrated in (c) and (d) of FIG. 3, the variable circuit element 235 may be configured as any one of the variable capacitor 340 and the variable capacitance diode 350. On the other hand, although not shown in the drawing, the variable circuit element 235 may be composed of a combination of a switch, a plurality of fixed capacitors, and fixed inductors.

4 is a diagram showing electrical characteristics of a band cancellation filter implemented through a coupling element and a variable circuit element. Referring to FIG. 4, a value of S12 indicating isolation among S parameters indicates characteristics of a band cancellation filter. Accordingly, it can be confirmed that the isolation between antenna elements is very improved in a frequency band where the value of S11 representing the reflection characteristic among the S parameters is the smallest.

5 is a view showing electrical characteristics of a band cancellation filter implemented by changing a coupling element and a variable circuit element in a low frequency or high frequency band. As shown in (a) of FIG. 5, it can be confirmed that the isolation frequency is changed according to the structure change of the coupling element in the low frequency band. In addition, it can be seen that the isolation frequency (isolaton frequency) is changed according to the structure of the coupling element in the high-frequency band, as shown in Figure 5 (b). On the other hand, although not shown in the drawing, it will be apparent to those skilled in the art that the value of the resonant frequency (that is, the isolation frequency) showing the characteristics of the BSF filter can be changed by changing the value of the variable circuit element in the low or high frequency band.

The coupling element 230 and the variable circuit element 235 formed as described above implement characteristics of the BSF filter between the first and second antenna elements 210 and 220 in the low frequency and high frequency bands, so that the first and The isolation between the second antenna elements 210 and 220 can be effectively improved.

Referring to FIG. 2 again, the antenna device 200 according to the first embodiment of the present invention includes first and second variable frequencies of the first and second antenna elements 210 and 220 (that is, operating frequencies). Two frequency variable elements (215, 225) may be further included.

The first variable frequency element 215 is connected in series between the first ground line 212 of the first antenna element 210 and the ground portion of the printed circuit board 240, so that the first antenna element 210 The resonant frequency is varied. On the other hand, although not shown in the drawing, the first frequency variable element 215 is in parallel between the first feeding line 211 of the first antenna element 210 and the feeding portion 214 of the printed circuit board 240. Connected, it is possible to vary the resonance frequency of the first antenna element 210.

The second variable frequency element 225 is connected in parallel between the second feeding line 221 of the second antenna element 220 and the feeding portion 224 of the printed circuit board 240, so that the second antenna element ( 220) to vary the resonance frequency. On the other hand, 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 ground portion of the printed circuit board 240, The resonance frequency of the second antenna element 220 may be varied.

6 is a diagram illustrating a configuration of a frequency variable element provided in the antenna device according to the first embodiment of the present invention. As illustrated in FIG. 6A, the first and second frequency variable elements 215 and 225 may include a switch 610 and a plurality of fixed capacitors 620. In addition, as illustrated in FIG. 6B, the first and second frequency variable elements 215 and 225 may include a switch 610 and a plurality of fixed inductors 630. In addition, as shown in (c) and (d) of FIG. 6, the first and second frequency variable elements 215 and 225 may be configured as any one of the variable capacitor 630 and the variable capacitive diode 640. have. Further, although not shown in the drawings, the first and second frequency variable elements 215 and 225 may be configured by a combination of a switch, a plurality of fixed capacitors, and fixed inductors.

When the Muti Co-band is supported, the first and second frequency variable elements 215 and 225 adjust the resonance frequency values of each antenna so that the resonance frequencies of the first and second antenna elements 210 and 220 do not overlap with each other. Variable to maximize isolation between antenna elements.

Table 1 below is a scenario in which the resonance frequencies of the first and second antenna elements are varied in order to maximize isolation between antenna elements in a dual sim dual active (DSDA) 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 first and second antenna elements 210 and 220 are changed by changing the values of the first and second frequency variable elements 215 and 225 according to a control command for each operating frequency. The resonant frequency is varied. 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 each other, thereby maximizing the isolation between each antenna element.

As described above, as described above, the antenna device according to the first embodiment of the present invention can improve the isolation between antenna elements by implementing a characteristic of a band cancellation filter between the first and second antenna elements. In addition, when two antenna elements adjacent to each other operate in the same frequency band, the antenna device may maximize isolation between each antenna element by varying the resonance frequencies of the first and second 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 having a slot antenna and a PIFA antenna (or monopole antenna) This will be explained in detail.

Example 2

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

Referring to FIG. 7, the conventional antenna device 700 includes a slot antenna 710 located at the bottom left of the mobile terminal and a PIFA antenna 720 positioned at the bottom 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, the metal frame 711 and a printed circuit board ( 713) a slot 712 for determining resonance characteristics of the corresponding antenna as an empty space between the first power supply units 715 positioned at the upper right of the slot 712 to supply power to the corresponding slot 712, And a first feeding line 714 vertically connecting the first feeding part 715 and the right area of the printed circuit board 713.

The PIFA antenna 720 is located in an area of a printed circuit board (not shown), and a second feeding unit 723 for supplying power to the corresponding antenna, a second feeding line connected to the second feeding unit 723 ( 722), an antenna pattern 721 that is connected to the second feed line 722 and emits an RF signal to the outside.

In the case of such a conventional antenna device 700, the first feeding part 715 and the first feeding line 714 of the slot antenna 710 are disposed adjacent to the PIFA antenna 720, and mutual coupling Due to this, there is a problem in that the isolation between each antenna element rapidly decreases. Therefore, by changing the structure of the slot antenna, when multi-co-band support, we propose an antenna device of a new structure that can improve the isolation between each antenna element.

8 (a) is a diagram schematically showing a structure of an antenna device for a mobile terminal according to a second embodiment of the present invention, and FIG. 8 (b) is a detailed structure of a printed circuit board forming a slot antenna It is a diagram showing.

Referring to (a) of FIG. 8, the antenna device 800 according to the second embodiment of the present invention includes a slot antenna 810 located at the lower left of the mobile terminal and a PIFA antenna 820 located at the lower right of the mobile terminal. It includes.

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, the metal frame 811 and a printed circuit board 801. A slot 812 for determining resonance characteristics of the corresponding antenna as an empty space between the first feeding unit 818 and the first feeding unit 818 that are located at the upper left of the slot 812 to supply power. The first feeding line 813 connected to the, the first feeding line 813 and the slot feeding line 814 extending in the horizontal direction to connect the ground layer (ground layer, 817) of the printed circuit board 801 , A matching circuit 815 forming an antenna resonance together with the slot feeding line 814, and a contact member 819 forming an antenna resonance by combining with a radiation pattern on an antenna carrier.

The printed circuit board 801 is a ground layer 817 forming a slot 812 by ground coupling with a metal frame 811, a plurality of vias connecting the ground layer 817 and the slot feeding line 814 ( 816). A slot 812 is formed through the metal frame 811, the ground layer 817, and the via 816, and the thickness of the formed slot corresponds to the thickness of the via 816. Therefore, the resonance characteristic of the slot antenna 810 varies according to the thickness of the via 816.

The slot antenna 810 formed in such a structure may 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, and combinations thereof, and the value may be changed according to the value of the resonance frequency required by the terminal system. .

The PIFA antenna 820 is located in an area of a printed circuit board (not shown), and a second feeding part 823 for supplying power to the corresponding antenna, and a second feeding line connected to the second feeding part 823 ( 822), it is connected to the second feed line 822 and consists of an antenna pattern 821 that radiates an RF signal to the outside.

As shown in (a) of FIG. 8, the first feeder 818 of the slot antenna 810 and the second feeder 823 of the PIFA antenna 820 are formed to be arranged side by side on both sides of the bottom of the terminal. do. That is, in order to minimize mutual interference between antenna elements, the distance between the first feeder 818 of the slot antenna 810 and the second feeder 823 of the PIFA antenna 820 is spaced as far apart as possible.

The antenna device 800 formed in such a structure may improve mutual isolation characteristics between antenna elements by minimizing mutual interference due to surface current induced by each antenna element when supporting multi co-band.

9 (a) shows the electrical characteristics of the conventional antenna device for a mobile terminal, and FIG. 9 (b) is a view showing the electrical characteristics of the antenna device according to the second embodiment of the present invention.

Referring to (a) and (b) of Figure 9, when Multi Co-band (eg, 900MHz, 1.9GHz) support, the conventional antenna device 700, -10dB level of isolation characteristics in the 1.9GHz band ( S12), the antenna device 800 according to the present invention exhibits an isolation characteristic of -18 dB level in the 1.9 GHz band. Therefore, it can be seen that in the high frequency band, the isolation characteristic of about 8 dB is improved through the structure change of the slot antenna 810 and the insertion of the matching circuit 815.

Meanwhile, in the present exemplary embodiment, the PIFA antenna 820 is illustrated in the lower right corner of the mobile terminal, but is not limited thereto, and a mono pole antenna or a slot antenna may be installed instead of the PIFA antenna 820.

For example, as illustrated in (a) of FIG. 10, a slot antenna 1010 may be installed at the bottom left of the mobile terminal, and a mono pole antenna 1030 may be installed at the bottom right of the mobile terminal. As described above, the power supply unit 1020 of the slot antenna 1010 and the power supply unit 1040 of the monopole antenna 1030 are formed to be arranged side by side on both sides of the bottom of the mobile terminal.

In addition, as shown in (b) of FIG. 10, a first slot antenna 1050 may be installed at the bottom left of the mobile terminal, and a second slot antenna 1070 may be installed at the bottom right of the mobile terminal. As described above, the power feeding part 1060 of the first slot antenna 1050 and the power feeding part 1080 of the second slot antenna 1070 are formed to be arranged side by side on both sides of the bottom 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 antenna elements by changing the structure of a slot antenna and inserting a matching circuit when supporting multi co-band. can do.

The above-described present invention can be embodied as computer readable codes on a medium on which a program is recorded. The computer-readable medium includes any kind of recording device in which data readable by a computer system is stored. Examples of computer-readable media include a hard disk drive (HDD), solid state disk (SSD), silicon disk drive (SDD), ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data storage device. This includes, and is also implemented in the form of a carrier wave (eg, transmission over the Internet). In addition, the computer may include a control unit 180 of the terminal. Accordingly, the above detailed description should not be construed as limiting in all respects, but should be considered illustrative. The scope of the invention should be determined by rational interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the 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 boards;
A first antenna element including a first feeding line connected to a feeding portion of the printed circuit board, a first grounding line connected to a ground portion of the printed circuit board, and a first antenna pattern emitting a first RF signal ;
A second antenna element including a second feeding line connected to a feeding portion of the printed circuit board, a second grounding line connected to a ground portion of the printed circuit board, and a second antenna pattern emitting a second RF signal ;
A coupling element disposed at a predetermined distance from the first antenna element and the second antenna element;
Includes; a variable circuit element connected between the coupling element and the ground, forming a band cancellation filter (Band Stop Filter) with the coupling element;
The first antenna element and the second antenna element are formed in a symmetrical shape around the coupling element,
The coupling element is arranged in a form parallel to the first antenna pattern and the second antenna pattern and the coupling pattern is coupled,
An antenna device disposed in parallel with the first ground line and the second ground line, and including a coupling ground line connecting the coupling pattern and the variable circuit element. According to claim 1,
The first antenna pattern and the second antenna pattern are formed in a form in which two ends face each other after being bent at least once starting from the first feeding line or the second feeding line,
The coupling pattern is an antenna device, characterized in that formed in a symmetrical structure of the T-shape. According to claim 1,
And a first frequency variable circuit connected in series between the first ground line and the ground part to vary a resonance frequency of the first antenna element. According to claim 1,
And a second frequency variable circuit connected in parallel between the second feed line and the feed part to vary a resonance frequency of the second antenna element. According to claim 1,
The first antenna element and the second antenna element is an antenna device characterized in that the planar inverted F antenna (Planar Inverted-F Antenna, PIFA).

Images