Patent Publication Number: US-8525739-B2

Title: Antenna device and portable terminal having the same

Description:
CROSS-REFERENCE TO A RELATED APPLICATION 
     Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2009-0118688, filed on Dec. 2, 2009, the contents of which is incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a portable terminal, and particularly, to a portable terminal having an antenna device for transmitting and receiving wireless signals. 
     2. Background of the Invention 
     In general, a terminal may be classified into a mobile (portable) terminal and a stationary terminal according to a moveable state. The mobile terminal may be also classified into a handheld terminal and a vehicle mount terminal according to a user&#39;s carriage method. 
     As functions of the terminal become more diversified, the terminal can support more complicated functions such as capturing images or video, reproducing music or video files, playing games, receiving broadcast signals, and the like. By comprehensively and collectively implementing such functions, the mobile terminal may be embodied in the form of a multimedia player or device. 
     Various attempts have been made to implement complicated functions in such a multimedia device by means of hardware or software. For instance, a User Interface (UI) environment is provided in a portable terminal to enable a user to easily and conveniently search for or select a desired function among available functions. 
     As the portable terminal is regarded as personal belongings to express a user&#39;s personality, various designs are required. 
     The various designs include structural changes and improvements to enhance the user&#39;s convenience. For the structural changes and improvements, an antenna device may be researched. 
     SUMMARY OF THE INVENTION 
     Therefore, an object of the present invention is to provide a portable terminal having an antenna device of a more enhanced function. 
     Another object of the present invention is to provide a portable terminal having a slimmer configuration, and an antenna device. 
     To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a portable terminal, comprising: a terminal body; a radiator formed of a conductive material and configured in a preset pattern so as to transmit or receive wireless signals; a circuit board mounted to the body, and configured to process the wireless signal by being electrically connected to the radiator; and an artificial magnetic conductor module disposed near the radiator, and configured to reflect the wireless signal, wherein the artificial magnetic conductor module comprises a conductive ground layer, a first conductive layer electrically connected to the conductive ground layer, and having a plurality of first conductors arranged at positions spacing from the conductive ground layer, and a second conductive layer formed to cover the first conductive layer and having second conductors arranged in parallel to the first conductors. 
     According to one embodiment of the present invention, slits may be formed between the first conductors adjacent to each other, and the second conductors may be arranged to cover the slits. The second conductors may be arranged at the same interval as the first conductors. 
     According to another embodiment of the present invention, each of the first and second conductors may be provided with a length and a width, and may be arranged so as to be long in a length direction and so as to be consecutive in a width direction. Each of the first and second conductive layers may be arranged such that the first and second conductors are disposed on one line in one direction. The radiator may be formed so as to be parallel to the second conductor at a position adjacent to the second conductor. A spacing distance between the first conductive layer and the second conductive layer may be shorter than a spacing distance between the conductive ground layer and the first conductive layer. 
     According to another embodiment of the present invention, the artificial magnetic conductor module may further comprise a first dielectric substance filled between the conductive ground layer and the first conductive layer; and a second dielectric substance filled between the first conductive layer and the second conductive layer. The first dielectric substance may be provided with an upper surface, a lower surface, and side surfaces. The first conductors may be formed on the upper surface of the first dielectric substance, and the conductive ground layer may be formed on the lower surface of the first dielectric substance. On the side surfaces of the first dielectric substance, may be formed a connection path for electrically connecting the first conductors arranged at an edge of the first dielectric substance to the conductive ground layer. 
     According to another embodiment of the present invention, the portable terminal may comprise a supporting member. One surface of the supporting member may be arranged at the second conductive layer, and another surface of the supporting member may be provided with the radiator. The supporting member may be implemented as a thin film formed of a non-conductive material. The supporting member or the radiator may be configured to cover one or more parts of each of the second conductors. 
     According to another embodiment of the present invention, at least one of a display for displaying visual information and a user input unit for inputting a control command may be disposed on one surface of the body. The artificial magnetic conductor module may be disposed near the display or the user input unit, and the radiator may be disposed near another surface of the body. 
     According to another embodiment of the present invention, the artificial magnetic conductor module may be mounted to the circuit board, and each of the conductive ground layer and the radiator may be electrically connected to the circuit board. Via holes through which the conductive ground layer and a ground layer of the circuit board are electrically connected to each other may be formed at the circuit board. 
     To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is also provided an antenna device for a portable terminal, the antenna device comprising: a radiator formed in a preset pattern so as to transmit or receive wireless signals; and an artificial magnetic conductor module disposed near the radiator, and configured to reflect the wireless signal, wherein the artificial magnetic conductor module comprises a conductive ground layer, a first conductive layer conductors electrically connected to the conductive ground layer, and having a plurality of first conductors arranged at positions spacing from the conductive ground layer, and a second conductive layer formed to cover the first conductive layer and having second conductors arranged in parallel to the first conductors. 
     To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a portable terminal including a terminal body, a radiator including a conductive material, and configured in a preset pattern to transmit or receive wireless signals, a circuit board mounted to the terminal body, and configured to process the wireless signal by being electrically connected to the radiator, and an artificial magnetic conductor module disposed near the radiator, and configured to reflect the wireless signal. 
     To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is also provided an antenna device for a portable terminal, the antenna device including a radiator formed in including a preset pattern, so as and configured to transmit or receive wireless signals; and an artificial magnetic conductor module disposed near the radiator, and configured to reflect the wireless signal. 
     The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
       In the drawings: 
         FIG. 1  is a perspective view of a portable terminal according to one embodiment of the present invention; 
         FIG. 2  is a rear perspective view of the portable terminal of  FIG. 1 ; 
         FIG. 3  is a disassembled perspective view of a second body of the portable terminal of  FIG. 2 ; 
         FIG. 4  is a conceptual view showing radiation of electromagnetic waves by an antenna device of  FIG. 3 ; 
         FIG. 5  is a disassembled perspective view of the antenna device of  FIG. 3 ; 
         FIG. 6A  is an enlarged view of a circuit board and the antenna device of  FIG. 3 ; 
         FIG. 6B  is a planar view of an artificial magnetic conductor module of  FIG. 5 ; 
         FIG. 7  is a conceptual view showing a principle that the artificial magnetic conductor module of  FIG. 3  is formed of an artificial magnetic conductor; 
         FIGS. 8A and 8B  are respectively a perspective view and a rear disassembled perspective view of a portable terminal according to another embodiment of the present invention; 
         FIGS. 9A and 9B  are graphs respectively comparing total radiated power (TRP) when the AMC module is implemented with TRP when the AMC module is not implemented, and comparing a specific absorption ratio (SAR) of electromagnetic waves in a human&#39;s body when the AMC module is implemented with a SAR when the AMC module is not implemented; 
         FIGS. 10A to 10C  are conceptual views and a graph showing changes of radiation efficiency and a specific absorption ratio (SAR) of electromagnetic waves in a human&#39;s body according to a size of the artificial magnetic conductor module of the present invention; and 
         FIG. 11  is a block diagram of a portable terminal according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Description will now be given in detail of the present invention, with reference to the accompanying drawings. 
     For the sake of brief description with reference to the drawings, the same or equivalent components will be provided with the same reference numbers, and description thereof will not be repeated. 
     Hereinafter, a portable terminal according to the present invention will be explained in more detail. 
     The same reference numerals will be given to the same components as those of the aforementioned embodiment, and their explanations will be omitted. The singular expression of the present invention may include a plural concept unless distinctively differently defined. 
     The portable terminal according to the present invention may include a portable phone, a smart phone, a laptop computer, a digital broadcasting terminal, Personal Digital Assistants (PDA), Portable Multimedia Player (PMP), a navigation system, etc. 
       FIG. 1  is a perspective view of a portable terminal according to one embodiment of the present invention. 
     A body of the portable terminal  100  of the present invention comprises a first body  110 , and a second body  120  coupled to the first body  110  by being slid along at least one direction. The present invention may not be limited to the slide type portable terminal, but may be applied to various types such as a bar type, a folder type, a swing type, and a swivel type. 
     A state that the first body  110  completely overlaps the second body  120  may be referred to as a ‘closed configuration’, whereas a state that one or more parts of the second body  120  are exposed by the first body  110  may be referred to as an ‘open configuration’. 
     Under the closed configuration, the portable terminal is operated in a standby mode. However, the standby mode may be released by a user&#39;s manipulation. On the contrary, under the opened configuration, the portable terminal is operated in a call mode, etc. The call mode may be converted into the standby mode by a user&#39;s manipulation or after time lapses. 
     A case forming the appearance of the first body  110  (casing, housing cover, etc.) is formed by a front case  111  and a rear case  112 . Each kind of electronic components are mounted in a space formed by the front case  111  and the rear case  112 . If desired, one or more intermediate cases may be provided between the front case  111  and the rear case  112 . The front and rear cases are usually formed by injection-molding resin material, or formed using metallic material such as stainless steel (STS) and titanium (Ti). 
     On the front case  111  of the first body  110 , may be disposed a display unit  113 , an audio output unit  114 , a first image input unit  115  or a first manipulation unit  116 . 
     The display unit  113  may be implemented as a Liquid Crystal Display (LCD) module or an Organic Light Emitting Diodes (OLED) module, a Transparent OLED (TOLED) module, and so on. 
     The display unit  113  may also be configured to further include a touch pad for allowing information to be input by a user&#39;s touch. And, the display unit  113  may be configured to generate various tactile effects when being touched by a user. This may be implemented by a haptic module interworking with the display unit  113 . A representative tactile effect generated by the haptic module includes vibration. The haptic module may be variously arranged according to configuration aspects of not only the display unit  113 , but also the portable terminal. 
     The audio output unit  114  may be implemented as a speaker or a receiver. 
     The first image input unit  115  may be implemented as a camera module configured to capture a user&#39;s still images or moving images. 
     The first manipulation unit  116  is configured to receive commands to control the operation of the portable terminal according to the present invention. The first manipulation unit  116  may be implemented as a touch screen together with the display unit  113 . 
     Like the first body  110 , a case of the second body  120  may be formed by a front case  121  and a rear case  122 . 
     A second manipulation unit  123  may be disposed on a front surface of the front case  121  of the second body  120 . 
     A third manipulation unit  124 , a first audio input unit  125 , and an interface  126  may be disposed on at least one of the front case  121  and the rear case  122 . 
     The first to third manipulation units  116 ,  123  and  124  may be referred to as a manipulation unit, and may include any type of ones that can be manipulated in a user&#39;s tactile manner. 
     The manipulation unit may be implemented as dome switches or a touch pad for receiving commands or information by a user&#39;s push or touch operation, or may be implemented as a jog wheel or a joystick. 
     In the aspect of functions, the first manipulation unit  116  may be used to input commands such as START, END, and SCROLL, and the second manipulation unit  123  may serve numbers, characters, symbols, etc. And, the third manipulation unit  124  may serve as hot keys for performing specific functions such as activation of the first image input unit  115 . 
     The first audio input unit  125  may be implemented as a microphone so as to receive a user&#39;s voice or other sounds. 
     The interface  126  may serve as a passage through which the portable terminal of the present invention exchanges data with an external device. For instance, the interface  126  may be implemented as at least one of a wired/wireless connection port for connecting an earphone to the portable terminal, a short-range communications port (e.g., an Infrared Data Association (IrDA) port, a Bluetooth port, a wireless LAN port, etc.), power supply ports for providing power to the portable terminal, or the like. 
     The interface  126  may be configured using a card socket (e.g., for coupling to a memory card, a subscriber identity module (SIM) card, a user identity module (UIM) card, etc.). 
       FIG. 2  is a perspective view of a rear surface of the portable terminal of  FIG. 1 . 
     Referring to  FIG. 2 , a second image input unit  128  may be additionally mounted to a rear surface of the rear case  122 . The second image input unit  128  faces a direction which is opposite to a direction faced by the first image input unit  115  (refer to  FIG. 1 ), and may have pixels different from those of the first image input unit  115 . 
     For example, the first image input unit  115  may operate with relatively lower pixels (lower resolution). Thus, the first image input unit  115  may be useful when a user can capture his face and send it to a calling party in a video call mode or the like. On the other hand, the second image input unit  128  may operate with a relatively higher pixels (higher resolution) such that it can be useful for a user to obtain higher quality pictures for later use. 
     A flash  129  and a mirror  130  may be additionally disposed adjacently to the second image input unit  128 . When capturing an object by using the second image input unit  128 , the flash  129  provides light to the object. The mirror  130  can cooperate with the second image unit  128  to allow a user to photograph himself or herself in a self-portrait mode. 
     It was explained that the second image input unit  128  is disposed at the second body  120 . However, the position of the second image input unit  128  is not limited to the second body  120 . For instance, at least one of the components  128  to  131  originally disposed at the rear case  122  may be mounted to the rear case  112  of the first body  110 . In this case, the components disposed at the rear case  112  may be protected by the second body  120  in the closed configuration. Furthermore, even if the second image input unit  128  is not additionally provided, the first image input unit  115  configured to be rotatable may capture an image even in a capturing direction by the second image input unit  128 . 
     A second audio output unit  131  may be additionally disposed at the rear case  122 . 
     The second audio output unit  131  may implement a stereo function together with the first audio output unit  114  (refer to  FIG. 1 ), and may be used for calling in a speaker phone mode. 
     An antenna for calling, Bluetooth communication or GPS communication, etc. may be provided at the terminal body. A broadcast signal receiving antenna  132  as well as the antenna may be disposed at the rear case  112 . The broadcast signal receiving antenna  132  may be configured to retract into the first body  110 . 
     One portion of a slide module  133  that slidably couples the first body  110  and the second body  120  to each other is disposed at the rear case  112  of the first body  110 . Another portion of the slide module  133  is disposed at the front case  121  of the second body  120 , thereby not being exposed out. 
     A power supply unit  127  for supplying power to the portable terminal is mounted at the rear case  122 . The power supply unit  127  may be a rechargeable battery, for example, to be detachably mounted to the rear case  122  for charging. 
       FIG. 3  is a disassembled perspective view of the second body  120  of the portable terminal of  FIG. 2 , and  FIG. 4  is a conceptual view showing radiation of electromagnetic waves by an antenna device  140  of  FIG. 3 . 
     Referring to  FIGS. 3 and 4 , a circuit board  118  is arranged so as to be adjacent to one end of the second body  120 . For instance, the circuit board  118  is mounted to the front case  121  or the rear case  122  of the second body  120 . The circuit board  118  is arranged so as to be covered by an inner surface of the rear case  122 . 
     The circuit board  118  is arranged on a rear surface of the second manipulation unit  123  (refer to  FIG. 1 ) adjacent to one end of the second body  120 , and switches configured to receive control commands by the second manipulation unit  123  may be mounted to one surface of the circuit board  118 . 
     The circuit board  118  may be implemented as one example of the controller  180  (refer to  FIG. 11 ) for controlling the portable terminal so as to operate each function. The circuit board  118  is configured to process a signal corresponding to a wireless electromagnetic wave transmitted or received by the antenna device  140 . 
     The antenna device  140  is mounted on another surface of the circuit board  118  in the present invention. However, the present invention is not limited to this. For instance, the antenna device  140  may be mounted on the rear case  122  of the second body  120 , or on the front case  111  and the rear case  112  of the first body  110 . 
     The antenna device  140  includes a radiator  141  implemented as a conductive material forms a preset pattern so as to transmit and receive wireless signals. The radiator  141  is electrically connected to the circuit board  118  so as to process wireless signals. 
     The radiator  141  is formed so as to transmit and receive a wireless electromagnetic wave of a specific frequency bandwidth. The frequency bandwidth may correspond to a Global Positioning System (GPS), Bluetooth), MediaFLO (Media Forward Link Only), a wireless communications system, etc. 
     An artificial magnetic conductor (AMC) module  150  configured to reflect wireless signals is arranged so as to be adjacent to the radiator  141 . The AMC module  150  is mounted on the circuit board  118 , and the radiator  141  is mounted on the AMC module  150 . More concretely, the radiator  141  is arranged so as to be adjacent to an inner surface of the rear case  122 . 
     Referring to  FIG. 4 , a radiated state of electromagnetic waves implemented by the AMC module  150  is different from that when the AMC module  150  is not implemented. 
     Electromagnetic waves are radiated to one direction due to reflection by the AMC module  150 , and the sum of direct electromagnetic waves (ED) and reflected electromagnetic waves (ER=ED) reflected from the AMC module  150  is entire electromagnetic waves (ET) radiated to one direction. The reason is because a zero phase difference is generated when electromagnetic waves are reflected from the AMC module  150 , and thereby an image current is generated in the same direction. 
     Referring to  FIG. 3  again, the AMC module  150  reflects electromagnetic waves toward the front case  122  among electromagnetic waves radiated from the radiator  141 , toward the rear case  122 . Generally, during wireless communications, one surface of the front case  122  is toward a user&#39;s head, and electromagnetic waves toward the front case  122  are absorbed into a human&#39;s body. However, as the AMC module  150  is configured to reflect electromagnetic waves, a specific absorption rate (SAR) of electromagnetic waves in a human&#39;s body may be decreased, and radiating efficiency may be enhanced. 
     The rear case  121  may be formed of a metallic material. Since the AMC module  150  is configured to reflect electromagnetic waves, an antenna performance is not degraded even if the rear case  121  is formed of a metallic material. 
     Hereinafter, a detailed structure of the antenna device  140  will be explained with reference to  FIGS. 5 to 7 .  FIG. 5  is a disassembled perspective view of the antenna device of  FIG. 3 ,  FIG. 6A  is an enlarged view of the circuit board  118  and the antenna device  140  of  FIG. 3 ,  FIG. 6B  is a planar view of the artificial magnetic conductor (AMC) module  150  of  FIG. 5 , and  FIG. 7  is a conceptual view showing a principle that the AMC module  150  of  FIG. 3  is formed of an artificial magnetic conductor. 
     Referring to  FIGS. 5 to 7 , the AMC module  150  includes a conductive ground layer  151 , and first and second conductive layers  152  and  153 . 
     The conductive ground layer  151  may be formed of a metallic material, and serve as a ground of an electric circuit formed by the AMC module  150 . 
     The first conductive layer  152  is electrically connected to the conductive ground layer  151 , and has a plurality of first conductors  152   a  arranged at positions spacing from the conductive ground layer  151 . 
     The second conductive layer  153  is formed to cover the first conductive layer  152  at positions spacing from the first conductive layer  152 . The second conductive layer  153  has a plurality of second conductors  153   a  arranged in parallel to the first conductors  152   a.    
     Each of the first and second conductors  152   a  and  153   a  is provided with a length and a width, and is arranged so as to be long in a length direction and so as to be consecutive in a width direction. More concretely, the first and second conductors  152   a  and  153   a  are arranged on one line in one direction. This arrangement allows simple fabrication processes, and a low defective ratio at the time of the fabrications. 
     Referring to  FIG. 5 , the AMC module  150  includes first and second dielectric substances  154  and  155 . 
     The first dielectric substance  154  is filled between the conductive ground layer  151  and the first conductive layer  152 , and the second dielectric substance  155  is filled between the first conductive layer  152  and the second conductive layer  153 . That is, the AMC module  150  has a structure that the conductive ground layer  151 , the first dielectric substance  154 , the first conductive layer  152 , the second dielectric substance  155 , and the second conductive layer  153  are sequentially laminated on each other. 
     Referring to  FIGS. 6A and 6B , the second conductors  153   a  are arranged to cover a gap between the first conductors  152   a  adjacent to each other. That is, the first and second conductive layers  152  and  153  are implemented so that centers of arrangement pitches of the first and second conductors  152   a  and  153   a  can not be on the same line. 
     The second conductors  153   a  may be arranged at the same interval as the first conductors  152   a . A slit  152   b  is formed between the first conductors  152   a  of the first conductive layer  152 , and the slit  152   b  is positioned at each center of the second conductors  153   a.    
       FIG. 7  is a conceptual view showing a principle that the AMC module  150  of  FIG. 5  is formed of an artificial magnetic conductor. 
     Referring to the illustrated parameters, an impedance (Z) between the first and second conductive layers  152  and  153  may be expressed as the following formula. Here, the ‘1/λ’ indicates a frequency, and the ‘∈’ indicates a dielectric constant. 
     
       
         
           
             Z 
             = 
             
               
                 
                   - 
                   j 
                 
                 ⁢ 
                 
                     
                 
                 ⁢ 
                 d 
                 ⁢ 
                 
                     
                 
                 ⁢ 
                 λ 
               
               
                 
                   πɛ 
                   ⁡ 
                   
                     ( 
                     
                       b 
                       - 
                       
                         2 
                         ⁢ 
                         a 
                       
                     
                     ) 
                   
                 
                 ⁢ 
                 b 
               
             
           
         
       
     
     An impedance (Z 11 ) between the first conductive layer  152  and the conductive ground layer  151  may be expressed as the following formula.
 
Z 11 =jkD
 
k√{square root over (∈ 1 )}D&lt;&lt;1
 
     An entire impedance (Z 22 ) may be expressed as the following formula. 
     
       
         
           
             
               Z 
               22 
             
             = 
             
               
                 
                   Z 
                   11 
                 
                 ⁢ 
                 Z 
               
               
                 
                   Z 
                   11 
                 
                 + 
                 Z 
               
             
           
         
       
     
     Accordingly, the entire impedance (Z 22 ) has a limitless value in a condition that ‘Z+Z 11 =0’. 
     Referring to  FIGS. 5 and 6 , the radiator  141  is formed in parallel to the second conductors  153   a  at a position adjacent to the second conductors  153   a . More concretely, the radiator  141  is formed at a supporting member  142 . 
     One surface of the supporting member  142  is arranged so as to cover the second conductive layer  153 , and another surface of the supporting member  142  is provided with the radiator  141 . The radiator  141  is implemented as a thin film formed of copper and silver, and is patterned on a surface of the supporting member  142 . The supporting member  142  may be implemented as a thin film formed of a non-conductive material such as synthetic resin. 
     A spacing distance between the first conductive layer  152  and the second conductive layer  153  may be shorter than a spacing distance between the conductive ground layer  151  and the first conductive layer  152 . That is, the first dielectric substance  154  is formed to have a thickness thicker than that of the second dielectric substance  155 . 
     Referring to parameters of  FIG. 7 , a frequency may be expressed as follows. Here, the ‘C’ indicates a capacitance of the antenna device. 
     
       
         
           
             
               freq 
               HIS 
             
             = 
             
               c 
               
                 π 
                 ⁢ 
                 
                   2 
                 
                 ⁢ 
                 
                   
                     
                       ɛ 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       
                         Db 
                         ⁡ 
                         
                           ( 
                           
                             b 
                             - 
                             
                               2 
                               ⁢ 
                               a 
                             
                           
                           ) 
                         
                       
                     
                     d 
                   
                 
               
             
           
         
       
     
     If the spacing distance between the conductive ground layer  151  and the first conductive layer  152  is longer than the spacing distance between the first conductive layer  152  and the second conductive layer  153 , a frequency transmitted or received by the radiator  141  may be included in a frequency band used in the portable terminal. More concretely, the frequency may be included in a frequency band of Wideband Code Division Multiple Access (W-CDMA). 
     Referring to  FIGS. 5 and 6A , the AMC module  150  may be mounted to the circuit board  118 , and the conductive ground layer  151  and the radiator  141  may be electrically connected to the circuit board  118 , respectively. 
     Each of the first and second dielectric substances  154  and  155  is provided with an upper surface, a lower surface and side surfaces. The first conductors  152   a  are arranged on the upper surface of the first dielectric substance  154 , and the conductive ground layer  151  is arranged on the lower surface of the first dielectric substance  154 . 
     On the side surfaces of the first dielectric substance  154 , formed is a connection path  156  for electrically connecting the first conductors  152   a  arranged at the edge of the first dielectric substance  154  to the conductive ground layer  151 . The connection path  156  is extending from the first conductive layer  152  toward two side surfaces of the first dielectric substance  154 , thereby being electrically connected to the conductive ground layer  151 . The connection path  156  may be formed by soldering, etc. 
     The supporting member  142  is arranged on the upper surface of the second dielectric substance  155 , and the lower surface of the supporting member  142  is configured to cover the first conductive layer  152 . The radiator  141  patterned on the supporting member  142  is extending to consecutive side surfaces of the first and second dielectric substances  154  and  155 , thereby being electrically connected to the circuit board  118 . 
     An extension portion  141   a  of the radiator  141  is electrically connected to the circuit board  118 . This may allow the radiator  141  to form a monopole antenna. However, the present invention is not limited to this. That is, the radiator  141  may form a planar inverted F antenna (PIFA), a dipole antenna, a strip antenna, etc. according to a structure of the connection path  156 . 
     Via holes  118   b  through which the conductive ground layer  151  and a ground layer  118   a  of the circuit board  118  are electrically connected to each other are formed at the circuit board  118 . That is, a ground of the AMC module  150  is extended through a path connected to the conductive ground layer  151 , via holes  118   b , and the ground layer  118   a.    
       FIGS. 8A and 8B  are respectively a perspective view and a rear disassembled perspective view of a portable terminal according to another embodiment of the present invention. 
     The portable terminal  200  is provided with a bar type terminal body. The terminal body includes a front case  201  and a rear case  202  which form the appearance of the portable terminal  200 , and a display unit  213  occupies most of a main surface of the front case  201 . 
     Referring to  FIGS. 8A and 8B , a radiator  241  is disposed toward the rear case  202 , and the AMC module  250  is arranged at a region adjacent to one end of two ends of the display unit  213 . A user input unit  216  may be arranged so as to overlap the AMC module  250 . 
     A second conductive layer  253  is provided with second conductors  253   a  arranged in the form of lattices. Although not shown, a first conductive layer  252  is also provided with first conductors  252   a  arranged in the form of lattices. The first and second conductive layers  252  and  253  are implemented so that arrangement pitches of the first and second conductors  252   a  and  253   a  can not be on the same line. The conductors  252   a  and  253   a  consist of cells having an approximate square shape. This may allow slits generated by the arrangement pitches to be formed as much as possible on the same area. Accordingly, an impedance of the AMC module  250  may be increased. 
     An advantage of the present invention to increase antenna efficiency by the AMC module will be explained in more detail with reference to  FIGS. 9A and 9B .  FIG. 9A  is a graph comparing total radiated power (TRP) when the AMC module is implemented with TRP when the AMC module is not implemented, and  FIG. 9B  is a graph comparing a specific absorption ratio (SAR) of electromagnetic waves in a human&#39;s body when the AMC module is implemented with a SAR when the AMC module is not implemented. 
     The graphs of  FIGS. 9A and 9B  show each TRP and each SAR of the portable terminal which is in a wireless communication, which have been measured from a lower part of a user&#39;s head to an upper part. Referring to  FIG. 9A , when the AMC module of the present invention is implemented, the TRP is improved by approximately 1.5 dB, and the SAR with respect to 1 g of electromagnetic waves is reduced by approximately 1.2 W/kg. 
       FIGS. 10A to 10C  are conceptual views and a graph showing changes of radiation efficiency and a specific absorption ratio (SAR) of electromagnetic waves in a human&#39;s body according to a size of the AMC module of the present invention. 
       FIG. 10A  illustrates an AMC module  350  (AMC  1 ) implemented by removing the first and second conductors  152   a  and  153   a  of the AMC module  150  of  FIG. 5  one by one, and  FIG. 10B  illustrates an AMC module  450  (AMC  2 ) implemented such that each of the second conductors is partially or entirely covered by the supporting member  442  or the radiator  441 . 
     The AMC module  450  (AMC 2 ) of  FIG. 10B  may be formed by removing the first and second conductors  152   a  and  153   a  from the AMC module  150  of  FIG. 5  as much as possible. 
     Referring to the graph of  FIG. 10C , it can be seen that a specific absorption ratio (SAR) of electromagnetic waves in a human&#39;s body is hardly increased even if the first and second conductors  152   a  and  153   a  are removed from the AMC module of  FIG. 5  until the AMC module  150  has a similar size to the radiator. Furthermore, a decrease width of total radiated power (TRP) in the AMC module of  FIG. 10C  is narrower than that in the AMC module  150  of  FIG. 5 . 
     Accordingly, as shown in  FIG. 10B , a small AMC module may be configured to have improved TRP and a reduced SAR. This may allow a slimmer portable terminal to be implemented. 
       FIG. 11  is a block diagram of the portable terminal according to the present invention. 
     Referring to  FIG. 11 , the portable terminal according to one embodiment of the present invention may comprise components, such as a wireless communication module  181 , manipulation units  116 ,  123  and  124 , image input units  115  and  128 , an audio input unit  125 , a display unit  113 , audio output units  114  and  131 , a sensing unit  186 , an interface  126 , a broadcast receiving module  185 , a memory  184 , a power supply unit  127 , and a controller  180 . 
     The controller  180  typically controls the overall operations of the portable terminal. For example, the controller  180  performs the control and processing associated with telephony calls, data communications, video calls, and the like. 
     Furthermore, the controller  180  not only performs the general functions, but also controls the operation of the portable terminal according to the present invention. 
     A wireless communications module  181  transmits or receives wireless signals to/from a base station through an antenna. For instance, the wireless communications module  181  transmits or receives voice data, text data, video data, and control data under control of the controller  180 . And, the wireless communications module  181  includes a transmitting portion  182  for transmitting a signal through a modulation process, and a receiving portion  183  for demodulating a received signal. 
     As shown in  FIG. 1 , the manipulation units  116 ,  123  and  124  provide, to the controller  180 , key input data input by a user so as to control the operation of the portable terminal. The manipulation units  116 ,  123  and  124  may be implemented as dome switches or a touch pad (e.g., static pressure/capacitance), or a jog wheel or a jog switch. 
     The image input units  115  and  128  process image frames of still images or moving images captured by an image sensor in a video call mode or a capturing mode. Then, the processed image frames are converted into video data that can be displayed on the display unit  113 , and then are output to the display unit  113 . 
     Under control of the controller  180 , the image frames processed by the image input units  115  and  128  may be stored in the memory  184 , or may be outwardly transmitted through the wireless communications module  181 . 
     The audio input unit  125  receives external audio signals by a microphone in a call mode, or a recording mode, or a voice recognition mode, and so on, and then processes the received audio signals into electric voice data. In the case of a call mode, the processed voice data is converted into data that can be transmitted to the base station through the wireless communications module  181 , and then is output to the wireless communications module  181 . In the case of a recording mode, the processed voice data is output so as to be stored in the memory  184 . 
     The audio input unit  125  may include assorted noise removing algorithms to remove noise generated in the course of receiving an external audio signal. 
     The display unit  113  may display information processed in the portable terminal. For instance, when the portable terminal is in a call mode, User Interface (UI) or Graphic User Interface (GUI) relating to a call is displayed under control of the controller  180 . When the portable terminal is in a video call mode or a capturing mode, a captured image or UI or GUI is displayed under control of the controller  180 . And, when the display unit  113  includes a touch screen, it serves as an input device as well as an output device. 
     In various modes including a call-receiving mode, a call-placing mode, a recording mode, a voice recognition mode and a broadcast reception mode, the audio output units  114  and  131  convert audio data received from the wireless communication module  181 , or audio data stored in the memory  184  thereby to outwardly output under control of the controller  180 . 
     The audio output units  114  and  131  output audio signals relating to functions executed in the portable terminal (e.g., call signal receiving sound, message receiving sound, and so on). The audio output units  114  and  131  include a speaker, a receiver, a buzzer, and so on. 
     The sensing unit  186  senses the current status of the portable terminal such as an open/close status of the portable terminal, a position of the portable terminal, and presence or absence of a user&#39;s contact with the portable terminal, thereby generating sensing signals to control the operation of the portable terminal. As an example, when the portable terminal is a slide-type portable terminal, the sensing unit  166  may sense whether a sliding portion of the portable terminal is open or closed. Then, the sensing unit  186  outputs results of the sensing to the controller  180 , and thereby the operation of the portable terminal is controlled. Other examples include the sensing unit  186  sensing the presence or absence of power provided by the power supply unit  127 , the presence or absence of coupling or other connection between the interface  126  and an external device, and so on. 
     The interface  126  interfaces a wire/wireless headset, an external charger, a wire/wireless data port, and a card socket (e.g., memory card, SIM/UIM card) rather than the portable terminal, with all types of external devices connected to the portable terminal. The interface  126  receives data or power from an external device, and transmits it to each component inside the portable terminal. Otherwise, the interface  126  transmits data inside the portable terminal to an external device. 
     The memory  184  may store a program to activate the controller  180 , or may temporarily store input/output data (e.g., phonebook, messages, still images, moving images, and so on). 
     Furthermore, the memory  184  stores a program for controlling the operation of the portable terminal of the present invention. 
     The memory  184  includes the concepts of the general hard disc, card-type memory (e.g., SD or XD memory), flash memory, RAM, ROM, and so on. 
     The broadcast receiving module  185  receives a broadcasting signal transmitted through satellite or terrestrial waves, etc., and converts the signal into broadcasting data that can be output to the audio output units  114  and  131 , and the display unit  113  thereby to output it to the controller  180 . The broadcast receiving module  185  receives broadcasting-related additional data (e.g., Electric Program Guide: EPG channel list, etc.). Broadcasting data and additional data converted by the broadcast receiving module  185  may be stored in the memory  184 . 
     The power supply unit  127  receives external or internal power under control of the controller  180 , and supplies the power to each component of the portable terminal. 
     The portable terminal of the present invention may have the following advantages. 
     Firstly, since the AMC module is arranged so as to be adjacent to the radiator, electromagnetic waves transmitted or received from/to the portable terminal may be radiated in one direction. This may implement an antenna device having improved TRP and a reduced SAR. 
     Secondly, a structure of a slimmer antenna may be implemented by laminating the AMC module and the radiator on each other, and design degrees of freedom with respect to an inner space of the portable terminal may be enhanced. 
     Thirdly, an external size of the AMC module may be reduced and an impedance of the AMC module may be increased by the first and second conductive layers. 
     The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present disclosure. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments. 
     As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.