Abstract:
The present disclosure relates to a pre-5 th -Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4 th -Generation (4G) communication system such as Long Term Evolution (LTE). The present invention relates to an assist device for an electronic device including an antenna, wherein the assist device includes a second unit including a second antenna, wherein the second antenna configured to generate capacitance with at least one of a first antenna in a first unit and an internal antenna of the electronic device. Further, the present invention also includes embodiments different from the above-described embodiment.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to an assist device that is used for an electronic device having an antenna. 
       BACKGROUND 
       [0002]    To meet the demand for wireless data traffic having increased since deployment of 4th generation (4G) communication systems, efforts have been made to develop an improved 5 th  generation (5G) or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a ‘Beyond 4G Network’ or a ‘Post Long Term Evolution (LTE) System’. 
         [0003]    The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G communication systems. 
         [0004]    In addition, in 5G communication systems, development for system network improvement is under way based on advanced small cells, cloud Radio Access Networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), reception-end interference cancellation and the like. 
         [0005]    In the 5G system, Hybrid frequency shift keying (FSK) and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) as an advanced coding modulation (ACM), and filter bank multi carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as an advanced access technology have been developed. 
         [0006]    Also, in modern society, electronic devices are used for various communications. Further, the growth of communication technologies results in the implementation of wireless communication based services in various electronic devices. In accordance with this, the kind of electronic devices including antennas for wireless communication is being gradually diversified. Physical space securing is essential for antenna performance securing. Generally, the antennas have the maximum performance at a size of λ/2 or λ/4. The λ means a wavelength at an operation frequency. However, in some cases, the size of the antenna is designed much smaller than the wavelength. Generally, the antenna of the size much smaller than the wavelength is called a ‘small antenna’. At this time, the performance of the small antenna is proportional to a size of the antenna. 
         [0007]    In case where a communication band is within a range of 700 MHz to 3000 MHz, the 700 MHz being a low band frequency has a wavelength of about 40 cm. For example, in case where a communication band of a portable terminal (e.g., a smart phone) is the 700 MHz, a space to install the antenna of the 40 cm size is not permitted. Accordingly, in a case of the low band, an antenna built in the portable terminal corresponds to a small antenna. Recently, portable terminals are on the trend of thickness decrease, screen increase, bezel decrease, etc. and accordingly to this, a space capable of mounting antennas is gradually decreasing. Furthermore, owing to the multi-functionality of the portable terminals, the number of parts mounted therein increases, and the securing of the space for mounting the antennas is getting more difficult. 
       DETAILED DESCRIPTION OF THE INVENTION 
     Technological Problem 
       [0008]    One exemplary embodiment of the present invention provides an apparatus for increasing antenna efficiency. 
         [0009]    Another exemplary embodiment of the present invention provides an apparatus including an additional antenna that has influence on a characteristic of an internal antenna of an electronic device. 
         [0010]    A further exemplary embodiment of the present invention provides an apparatus for changing a resonance frequency of an internal antenna of an electronic device. 
         [0011]    A yet another exemplary embodiment of the present invention provides an apparatus having different influence on an internal antenna of an electronic device in accordance with a usage status. 
         [0012]    A still another exemplary embodiment of the present invention provides an apparatus for improving a data transmission rate through antenna performance improvement. 
         [0013]    A still another exemplary embodiment of the present invention provides an apparatus for improving a broadcasting signal reception rate through antenna performance improvement. 
       Means for Solving Problem 
       [0014]    An assist device for an electronic device having an antenna according to an exemplary embodiment of the present invention, includes a second unit including a second antenna, and the second antenna is configured to generate capacitance with at least one of a first antenna in a first unit and an internal antenna of the electronic device. Here, a value of the capacitance can be varied depending on a relative position relationship between the first unit and the second unit. 
       Effects of the Invention 
       [0015]    By using for an electronic device an assist device including an antenna element according to exemplary embodiments of the present invention, the reception coverage of the electronic device increases, and effects of data transmission speed improvement, call reception performance improvement, etc. can be obtained. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  illustrates an example of a variation of antenna performance caused by a handgrip in an electronic device. 
           [0017]      FIG. 2  illustrates an example of an electronic device and an assist device according to an exemplary embodiment of the present invention. 
           [0018]      FIG. 3  illustrates an example of components of an assist device according to an exemplary embodiment of the present invention. 
           [0019]      FIGS. 4A to 4C  illustrate a status variation of an assist device according to an exemplary embodiment of the present invention. 
           [0020]      FIG. 5  illustrates an antenna structure of an assist device according to an exemplary embodiment of the present invention. 
           [0021]      FIGS. 6A to 6C  illustrate a capacitance variation dependent on a status of an assist device according to an exemplary embodiment of the present invention. 
           [0022]      FIG. 7  illustrates an example of an antenna characteristic variation dependent on a status of an assist device according to an exemplary embodiment of the present invention. 
           [0023]      FIG. 8  illustrates an equivalent circuit of antennas included in an assist device and an electronic device according to an exemplary embodiment of the present invention. 
           [0024]      FIGS. 9A to 9C  illustrate an example of substitutable structures of antennas included in an assist device according to an exemplary embodiment of the present invention. 
           [0025]      FIG. 10  illustrates an example of a variation of a resonance frequency dependent on a status variation of an assist device according to an exemplary embodiment of the present invention. 
           [0026]      FIG. 11  illustrates another example of a variation of a resonance frequency dependent on a status variation of an assist device according to an exemplary embodiment of the present invention. 
           [0027]      FIG. 12  illustrates an example of implementation of an assist device according to an exemplary embodiment of the present invention. 
           [0028]      FIG. 13  illustrates an example of a variation of a resonance frequency of an antenna of an electronic device caused by an assist device according to an exemplary embodiment of the present invention. 
           [0029]      FIGS. 14A to 14C  illustrate another example of implementation of an assist device according to an exemplary embodiment of the present invention. 
           [0030]      FIG. 15  illustrates a further example of implementation of an assist device according to an exemplary embodiment of the present invention. 
           [0031]      FIGS. 16A to 16C  illustrate an example of use of an assist device according to an exemplary embodiment of the present invention. 
           [0032]      FIG. 17  illustrates another example of use of an assist device according to an exemplary embodiment of the present invention. 
           [0033]      FIG. 18  illustrates antenna performance caused by an assist device according to an exemplary embodiment of the present invention. 
           [0034]      FIG. 19  illustrates an example of components of an assist device according to another exemplary embodiment of the present invention. 
           [0035]      FIG. 20  illustrates an equivalent circuit of antennas included in an assist device and an electronic device according to another exemplary embodiment of the present invention. 
       
    
    
     BEST MODE FOR EMBODIMENT OF THE INVENTION 
       [0036]    The operation principle of the present invention is described below in detail with reference to the accompanying drawings. In describing the present invention below, a detailed description of related well-known functions or constructions will be omitted if it is determined that a detailed description thereof may unnecessarily obscure the gist of the present invention. And, the terms described later, terms defined considering functions in the present invention, can be modified in accordance to user and/or operator&#39;s intention or practice, etc. Therefore, the definition should be given on the basis of content throughout the present specification. 
         [0037]    Below, the present invention describes a technology for improving the antenna performance of an electronic device including an antenna by means of an assist device. 
         [0038]    The terms, etc. for identifying components of an electronic device and an assist device used in the following description are for description convenience. Accordingly, the present invention is not limited to the terms described later, and can use other terms denoting objects having an equivalent technological meaning. 
         [0039]    In the present invention, the electronic device can be a portable electronic device, and can be one of a smart phone, a portable terminal, a mobile phone, a mobile pad, a media player, a tablet computer, a handheld computer or a Personal Digital Assistant (PDA). Also, the electronic device can be a device combining two or more functions among the aforementioned devices. 
         [0040]    An intuitive method for improving the antenna performance of an electronic device is to install an antenna outside the electronic device, thereby securing a relatively wide space for antenna installation. For example, a method of making an exterior of the electronic device from a metal frame and using the exterior as an antenna, a method of inserting an antenna pattern into a rear case of an antenna, a method of installing an antenna in a bumper case that is one of additional accessories, etc. can be taken into consideration. 
         [0041]    Or, an idea of additionally installing an external antenna physically coupled with an internal antenna of an electronic device, thereby extending an antenna space is available. But, the extension through the physical coupling may cause the following problems. A separate fastening terminal for physical coupling between the internal antenna and the external antenna is required. Owing to a structure of the electronic device, an installation position of the external antenna can be fixed to a specific range. For example, the installation position can include a rear case, a bumper case, a protection case, a protection film, etc. Also, because antenna space extension is restrictive, antenna performance improvement is restrictive as well. Further, in a case of a portable terminal (e.g., a smart phone), in a calling status, the influence of a user&#39;s handgrip can result in a deterioration of antenna performance. One example of the performance deterioration caused by the handgrip is given as in  FIG. 1  below.  FIG. 1  illustrates an example of a variation of antenna performance caused by a handgrip in an electronic device.  FIG. 1  represents a reflection coefficient dependent on a frequency. Referring to  FIG. 1 , it is checked that a frequency at which the reflection coefficient is minimal, i.e., a resonance frequency is varied depending on handgrip or non-handgrip. 
         [0042]    Accordingly, various exemplary embodiments of the present invention propose a way of improving antenna performance while avoiding influence from the human body. For the sake of this, new antenna space setting is required, and various exemplary embodiments of the present invention provide an assist device used for an electronic device. 
         [0043]      FIG. 2  illustrates an example of an electronic device and an assist device according to an exemplary embodiment of the present invention. 
         [0044]    Referring to  FIG. 2 , the assist device  210  can be physically attached to the electronic device  220 . In  FIG. 2 , the electronic device  220  is a portable terminal such as a smart phone, and the assist device  210  is a cover for the electronic device  220 . The assist device  210  can be denoted as a cover, a flip cover, a view cover, etc. The assist device  210 , a structure independent from the electronic device  220 , can be attached to an exterior of the electronic device  220 . Or, the assist device  210  can be coupled with a part of a component of the electronic device  220 . For example, the assist device  210  can include the entire of a rear cover of the electronic device  220  or a part thereof In this case, if the assist device  210  is eliminated, even the rear cover of the electronic device  220  is eliminated together. In  FIG. 2 , a hole is provided in a part of the assist device  210 , but the hole may not exist. 
         [0045]      FIG. 3  illustrates an example of components of an assist device according to an exemplary embodiment of the present invention. 
         [0046]    Referring to  FIG. 3 , the assist device consists of a first unit  320  and a second unit  330 . The first unit  320 , a component of the assist device attached to the electronic device, can be a structure that includes a part of a component (e.g., a rear cover) of the electronic device or is independent from the electronic device. That is, so long as the assist device is not eliminated, a relative position relationship between the first unit  320  and the electronic device is not changed. The first unit  320  includes a first side  322  and a second side  324 . The first side  322 , a side getting in contact with a rear side of the electronic device, can be denoted as an inner side. The second side  324 , a side opposite to the first side  322 , can be denoted as an outer side. 
         [0047]    The second unit  330  is a structure independent from the electronic device. The second unit  330  includes a first side  332  and a second side  334 . The first side  332 , a side getting in contact with a front side of the electronic device, can be denoted as an inner side. The second side  334 , a side opposite to the first side  332 , can be denoted as an outer side. The first unit  320  and the second unit  330  are mutually coupled with each other by means of materials having ductility or are coupled with each other through a hinge, whereby a relative position relationship between the second unit  330  and the electronic device can be changed. In accordance with this, the assist device can be in an open status, a close status, and/or a folding status. The statuses of the assist device can be defined as in FIGS.  4 A to  4 C below. 
         [0048]      FIGS. 4A to 4C  illustrate a status variation of an assist device according to an exemplary embodiment of the present invention.  FIG. 4A  illustrates a close status,  FIG. 4B  illustrates an open status, and  FIG. 4C  illustrates a folding status. 
         [0049]    Referring to  FIG. 4A , the close status is a status in which a first unit  420  and a second unit  430  are arranged substantially parallel to each other, and is a status in which the second unit  430  covers a front side of an electronic device  400 . That is, the close status is a status in which a first side, i.e., an inner side of the second unit  430  and the electronic device  400  are in contact with each other. In the close status, an outer side of the first unit  420  and an outer side of the second unit  430  are exposed. Also, in the close status, the front side of the electronic device  400  is not exposed. 
         [0050]    Referring to  FIG. 4B , the open status is a status in which the second unit  430  and the first unit  420  are arranged substantially side by side. In the open status, the outer side of the first unit  420  is exposed, and the inner side of the second unit  430  and the outer side thereof are exposed. Also, in the open status, the front side of the electronic device  400  is exposed. 
         [0051]    Referring to  FIG. 4C , the folding status is a status in which the second unit  430  and the first unit  420  are arranged substantially parallel to each other, and is a status in which the outer side of the second unit  430  and the outer side of the first unit  420  face each other. In the folding status, the inner side of the second unit  430  is exposed. Also, in the folding status, the front side of the electronic device  400  is exposed. 
         [0052]      FIG. 5  illustrates an antenna structure of an assist device according to an exemplary embodiment of the present invention. 
         [0053]    Referring to  FIG. 5 , an electronic device includes an internal antenna  506 , and the assist device includes a first antenna  526  and a second antenna  536 . In other words, the assist device according to an exemplary embodiment of the present invention can include at least one antenna. The antenna represents a conductive structure having a specific pattern that is designed for signal radiation or for helping the signal radiation. The first antenna  526  and the second antenna  536  which are included in the assist device can be called a ‘cover antenna’. 
         [0054]    The first antenna  526 , a main radiator of the cover antenna, includes a feeding part for capacitive coupling with the internal antenna  506 . That is, the first antenna  526  is capacitively coupled with the internal antenna  506 . The second antenna  536  is a means for changing an antenna characteristic depending on a status of the assist device. Here, the status includes an open status, a close status, and/or a folding status. 
         [0055]    In the example of  FIG. 5 , the internal antenna  506 , the first antenna  526 , and/or the second antenna  527  are positioned at lower ends of the electronic device and the assist device. But, the positions of the internal antenna  506 , the first antenna  526 , and/or the second antenna  527  are one example, and can be arranged in different positions. However, the positions of the first antenna  526  and the second antenna  527  can depend on the position of the internal antenna  506 . 
         [0056]    Also, in the example of  FIG. 5 , antenna patterns of the internal antenna  506 , the first antenna  526 , and/or the second antenna  527  are omitted. Concrete antenna patterns of the internal antenna  506 , the first antenna  526 , and/or the second antenna  536  can be different from one another on the basis of a signal band, an antenna type, a characteristic of the electronic device, desired capacitance, etc. 
         [0057]    In accordance with one exemplary embodiment of the present invention, the cover antenna can be included within the assist device. In this case, the cover antenna is installed at a time the assist device is manufactured. In accordance with another exemplary embodiment of the present invention, the cover antenna can be installed in an ex post manner by a user. For example, the cover antenna can be installed in the assist device in a form of being attached to the assist device through an adhesive, in other words, in a form of a sticker. In this case, the cover antenna can be attached to the assist device in a form of an antenna pattern printed on a non-conductive film, or can be attached to the assist device in a form of only the antenna pattern. 
         [0058]      FIGS. 6A to 6C  illustrate a capacitance variation dependent on a status of an assist device according to an exemplary embodiment of the present invention.  FIG. 6A  illustrates an open status,  FIG. 6B  illustrates a close status, and  FIG. 6C  illustrates a folding status.  FIG. 6  illustrates concrete antenna patterns, but the illustrated antenna patterns are one example and the present invention is not limited to this. 
         [0059]    Referring to  FIGS. 6A to 6C , capacitance is generated between a first antenna  626  included in a first unit  620  and a second antenna  636  included in a second unit  630 . However, capacitance of a different level is generated depending on the status of the assist device. In detail, capacitance of a level C 1  can be generated in the open status of  FIG. 6A , capacitance of a level C 2  can be generated in the close status of  FIG. 6B , and capacitance of a level C 3  can be generated in the folding status of  FIG. 6C . Concrete values of the C 1 , the C 2 , and/or the C 3  are determined on the basis of characteristics such as shapes of the first antenna  626  and the second antenna  636 , areas thereof, a relative position relationship therebetween, fragmented structures thereof, etc. Accordingly, the characteristics such as the shapes of the first antenna  626  and the second antenna  636 , the areas thereof, the relative position relationship therebetween, etc. are design variables that can be varied depending on antenna performance intended and targeted by an executor of the present invention. 
         [0060]      FIG. 7  illustrates an example of an antenna characteristic variation dependent on a status of an assist device according to an exemplary embodiment of the present invention.  FIG. 7  illustrates a characteristic of the entire antenna that includes all of an internal antenna of an electronic device and a first antenna and second antenna of the assist device.  FIG. 7  represents a reflection coefficient dependent on a frequency variation. A frequency at which the reflection coefficient is minimal is a resonance frequency. 
         [0061]    A frequency characteristic illustrated in  FIG. 7  is a characteristic of an antenna itself, in detail, a characteristic that does not consider the influence of other components (e.g., dielectric substance excepting an antenna pattern) of the assist device dependent on a usage status of the assist device and/or the influence of a user&#39;s handgrip. That is, a variation of the frequency characteristic illustrated in  FIG. 7  is for compensating an antenna characteristic variation caused by either the other components of the assist device or the handgrip. 
         [0062]    Referring to  FIG. 7 , a resonance frequency is varied depending on an open status, close status, and/or folding status of the assist device. In detail, when the assist device is not installed, the resonance frequency is f 0  and, when the assist device is in the open status, the resonance frequency is decreased to f 1 . In contrast, when the assist device is in the close status or the folding status, the resonance frequency is increased to f 2  or f 3 . Accordingly, in a case of the open status, if a resonance frequency increases by f 0 -f 1  due to an external factor, the influence of the external factor can be compensated through the frequency characteristic variation of  FIG. 7 . Also, in a case of the close status, if the resonance frequency decreases by f 2 -f 0  due to an external factor, the influence of the external factor can be compensated through the frequency characteristic variation of  FIG. 7 . Also, in a case of the folding status, if the resonance frequency decreases by f 3 -f 0  due to an external factor, the influence of the external factor can be compensated through the frequency characteristic variation of  FIG. 7 . 
         [0063]    Referring to the frequency characteristic variation exemplified in  FIG. 7 , the resonance frequency of the antenna itself is decreased in the open status, and the resonance frequency of the antenna itself is increased in the close statue or the folding status. That is, the example of  FIG. 7  is on the presumption that a resonance frequency is increased due to the external factor in the open status, and the resonance frequency is decreased due to the external factor in the close status or the folding status. But, if the resonance frequency is decreased due to the external factor in the open status, unlike the example of  FIG. 7 , the assist device can be designed such that the resonance frequency of the antenna itself is increased in the open status. Also, if the resonance frequency is increased due to the external factor in the close status or the folding status, unlike the example of  FIG. 7 , the assist device can be designed such that the resonance frequency of the antenna itself is decreased in the close status or the folding status. That is, the resonance frequency variation dependent on the status of the assist device can be different in accordance with various exemplary embodiments of the present invention. 
         [0064]      FIG. 8  illustrates an equivalent circuit of antennas included in an assist device and an electronic device according to an exemplary embodiment of the present invention. 
         [0065]    Referring to  FIG. 8 , an internal antenna  806 , a first antenna  826 , and/or a second antenna  836  are capacitively coupled with one another. C P1  between the internal antenna  806  and the first antenna  826  is a parasitic capacitance value generated between antenna patterns physically isolated from each other. The C P1  is not changed depending on a status of the assist device. C 12  between the first antenna  826  and the second antenna  836  is a capacitance value generated between antenna patterns physically isolated from each other, and can be changed depending on the status of the assist device. As one antenna, the internal antenna  806 , the first antenna  826 , and/or the second antenna  836  can radiate a signal. In an open status, a total capacitance of the antennas is given as in Equation 1 below. 
         [0000]    
       
         
           
             
               
                 
                   
                     C 
                     total 
                   
                   = 
                   
                     1 
                     
                       
                         1 
                         
                           C 
                           1 
                         
                       
                       + 
                       
                         1 
                         
                           C 
                           2 
                         
                       
                       + 
                       
                         1 
                         
                           C 
                           
                             P 
                              
                             
                                 
                             
                              
                             1 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
         [0066]    In Equation 1, the ‘C total ’ denotes a total capacitance of antennas, the ‘C 1 ’ denotes capacitance of an internal antenna of an electronic device, the ‘C 2 ’ denotes capacitance of a first antenna of an assist device, and the ‘C P1 ’ denotes parasitic capacitance between the internal antenna and the first antenna. 
         [0067]    Referring to Equation 1, the second antenna  836  does not have influence on the total capacitance C total . That is, in the open status, the second antenna  836  is the same as not being coupled. At this time, a resonance frequency f r  is given as Equation 2 below. 
         [0000]    
       
         
           
             
               
                 
                   
                     f 
                     r 
                   
                   = 
                   
                     1 
                     
                       
                         
                           L 
                           tot 
                         
                          
                         
                           C 
                           tot 
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
           
         
       
     
         [0068]    In Equation 2, the ‘f r ’ denotes a resonance frequency, the ‘L tot ’ denotes total inductance, and the ‘C tot ’ denotes total capacitance. 
         [0069]    A relationship between the parasitic capacitance C P1  and other variables is given as in Equation 3 below. 
         [0000]    
       
         
           
             
               
                 
                   
                     C 
                     
                       P 
                        
                       
                           
                       
                        
                       1 
                     
                   
                   ∝ 
                   
                     
                       
                         
                           ɛ 
                           r 
                         
                          
                         a 
                       
                       d 
                     
                      
                     
                         
                     
                      
                     Δ 
                      
                     
                         
                     
                      
                     
                       C 
                       P 
                     
                   
                   ∝ 
                   
                     f 
                     r 
                   
                 
               
               
                 
                   ( 
                   3 
                   ) 
                 
               
             
           
         
       
     
         [0070]    In Equation 3, the ‘C P1 ’ denotes parasitic capacitance between the internal antenna and the first antenna, the ‘ε r ’ denotes a permittivity of the assist device, the ‘a’ denotes an overlapped area overlapped between the internal antenna and the first antenna, the ‘d’ denotes a distance between the internal antenna and the first antenna, and the ‘f r ’ denotes a resonance frequency. 
         [0071]    The equivalent circuit of the antennas illustrated in  FIG. 8  is one example. Accordingly, the antennas according to an exemplary embodiment of the present invention can be implemented in other structures. For example, the antennas can be substituted with antennas of a scheme illustrated in  FIGS. 9A to 9C  below. 
         [0072]      FIGS. 9A to 9C  illustrate an example of substitutable structures of antennas included in an assist device according to an exemplary embodiment of the present invention. The equivalent circuit of the respective antennas illustrated in  FIG. 8  can have a CRLH structure of  FIG. 9A , an RLC structure of  FIG. 9B , and/or a traveling wave structure of  FIG. 9C . 
         [0073]    Referring to  FIG. 9A , the CRLH structure is a structure which includes a sub-circuit including a capacitor  978  arranged in parallel with serially coupled inductor  976  and capacitor  980 , and in which the sub-circuit, a capacitor  972  and an inductor  974  are serially coupled with one another. Referring to  FIG. 9B , the RLC structure is a structure which includes a sub-circuit including a resistor  984  and a capacitor  986  parallel coupled with each other, and in which the sub-circuit and an inductor  982  are serially coupled with each other. Referring to  FIG. 9C , the traveling wave structure is a structure which includes a sub-circuit including an inductor  992  and a resistor  996  serially coupled with each other, and in which the sub-circuit and a capacitor  994  are parallel coupled with each other. 
         [0074]      FIG. 10  illustrates an example of a variation of a resonance frequency dependent on a status variation of an assist device according to an exemplary embodiment of the present invention.  FIG. 10  illustrates a characteristic of the entire antenna that includes all of an internal antenna of an electronic device and a first antenna and second antenna of the assist device.  FIG. 10  represents a reflection coefficient dependent on a frequency variation. A frequency at which a reflection coefficient is minimal is a resonance frequency. 
         [0075]    Referring to  FIG. 10 , a resonance frequency is f 0  when the assist device is not installed. The resonance frequency is decreased to f 1  when the assist device is in an open status. In contrast, the resonance frequency is increased to f 2  when the assist device is in a close status. The resonance frequency variation in the close status is caused by the generation of the C 12  between the first antenna  826  and the second antenna  836  illustrated in  FIG. 8 . Accordingly to this, a variation of a resonance frequency caused by an external factor can be compensated. For example, a phenomenon in which a frequency is decreased due to a user&#39;s handgrip can be corrected. 
         [0076]    Unlike the antenna characteristic of  FIG. 7 , the antenna characteristic of  FIG. 10  does not consider a folding status of the assist device. That is, in accordance with various exemplary embodiments of the present invention, only some of three statuses (e.g., open status, close statue, and/or folding status) of the assist device can be selectively taken into consideration.  FIG. 10  exemplifies a case in which only the open status and the close status are considered. 
         [0077]      FIG. 11  illustrates another example of a variation of a resonance frequency dependent on a status variation of an assist device according to an exemplary embodiment of the present invention.  FIG. 11  illustrates a characteristic of the entire antenna including all of an internal antenna of an electronic device and a first antenna and second antenna of the assist device.  FIG. 11  represents a reflection coefficient dependent on a frequency variation. A frequency at which a reflection coefficient is minimal is a resonance frequency. 
         [0078]    Referring to  FIG. 11 , a resonance frequency is f 2  when the assist device is in a close status. The resonance frequency is increased to f 3  when the assist device is in a folding status. The resonance frequency variation in the folding status is caused by a variation of the C 12  between the first antenna  826  and the second antenna  836  illustrated in  FIG. 8 . Accordingly to this, a variation of a resonance frequency caused by an external factor can be compensated. For example, a phenomenon in which a frequency is decreased due to a user&#39;s handgrip can be corrected. 
         [0079]    Unlike the antenna characteristic of  FIG. 7 , an antenna characteristic of  FIG. 11  does not consider an open status of the assist device. That is, in accordance with various exemplary embodiments of the present invention, only some of three statuses (e.g., open status, close statue, and/or folding status) of the assist device can be selectively taken into consideration.  FIG. 11  exemplifies a case in which only the close status and the folding status are considered. 
         [0080]      FIG. 12  illustrates an example of implementation of an assist device according to an exemplary embodiment of the present invention. 
         [0081]    Referring to  FIG. 12 , the assist device includes a cover antenna  1246 . A Liquid Crystal Display (LCD) panel  1262  of an electronic device and a bracket  1264  thereof correspond to the ground. The cover antenna  1246  can be installed to maximize the performance of a sub antenna of an upper end of the electronic device. A feeding part of the cover antenna  1246  of the assist device is installed getting close to a main radiator of the sub antenna built in the electronic device, and a main radiator of the cover antenna  1246  is installed at an upper end of a front part of the assist device, whereby it can be implemented to minimize performance deterioration in a close status. It is desirable that a space of about {1/10×N×wavelength} or more is secured for the sake of installation of the cover antenna  1246 . Also, it is desirable that another conductor does not exist around the cover antenna  1246 . In this case, the maximum performance can be expected when the cover antenna  1246  is spaced {1/2×wavelength} apart from the ground in an open status, the close status, and/or a folding status. 
         [0082]    In a case of implementation of  FIG. 12 , an antenna operation band can be varied in the open status, the close status, and/or the folding status. That is, in a case of implementation considering only operating at a communication band in the open status, the antenna is resonated out of the communication band in the close status or the folding status, thereby causing performance deterioration. Accordingly, it is desirable to implement to generate an additional compensation factor (e.g., capacitance and/or inductance) in the close status and the folding status. In this case, an example of a variation of a resonance point of the antenna is given as in  FIG. 13  below. 
         [0083]      FIG. 13  illustrates an example of a variation of a resonance frequency of an antenna of an electronic device caused by an assist device according to an exemplary embodiment of the present invention.  FIG. 13  represents a reflection coefficient dependent on a frequency variation. Referring to  FIG. 13 , it is shown that a reflection coefficient in the open status is lower than at non-installation of the assist device. That is, it can be implemented to optimize performance in the open status. Also, the performance can be secured by implementing to form capacitance C close  with the front ground (e.g., the LCD panel  1262  and the bracket  1264 ) of the electronic device in the close status and to form capacitance C fold  with the rear ground of the electronic device in the folding status. 
         [0084]      FIGS. 14A to 14C  illustrate another example of implementation of an assist device according to an exemplary embodiment of the present invention.  FIG. 14A  illustrates a side view and front view of an open status,  FIG. 14B  illustrates a side view and front view of a close status, and  FIG. 4C  illustrates a side view and front view of a folding status. 
         [0085]    Referring to  FIGS. 14A to 14C , a cover antenna of an assist device  1410  includes a pattern 1   1471 , a pattern 2   1472 , and/or a pattern 3   1473 . In accordance with the status of the assist device  1410 , some of the pattern 1   1471 , the pattern 2   1472 , and the pattern 3   1473  can play as main patterns contributing to signal radiation, and the remnant can play as dummy patterns having no influence on the signal radiation. 
         [0086]    Referring to  FIG. 14A , in a case of the open status, the pattern 1   1471  is capacitively coupled with an internal antenna of an electronic device  1400 , and the pattern 2   1472  and the pattern 3   1473  do not contribute to signal radiation. That is, in the open status, the pattern 1   1471  becomes a main pattern, and the pattern 2   1472  and the pattern 3   1473  become dummy patterns. For example, a resonance frequency can be formed at a low band in accordance with a stub length of the pattern 1   1471 . In the open status, a broadband antenna of a low band can be implemented by a combination of a resonance frequency of the internal antenna of the electronic device  1400  and a resonance frequency of the pattern 1   1471 . 
         [0087]    Referring to  FIG. 14B , in a case of the close status, capacitance C close  is formed by the pattern 2   1472  distributed to a first unit and second unit of the assist device  1410 . Accordingly to this, the pattern 2   1472  is capacitively coupled with the pattern 1   1471 , and the pattern 1   1471  and the pattern 2   1472  have influence on signal radiation. That is, in the close status, the pattern 1   1471  and the pattern 2   1472  become main patterns, and the pattern 3   1473  becomes a dummy pattern. That is, in the open status, the pattern 2   1472  has no influence, but in the close status, the pattern 2   1472  can form capacitance with the front ground (e.g., bracket) of the electronic device  1400 , and generate a new resonance frequency. 
         [0088]    Referring to  FIG. 14C , in a case of the folding status, capacitance C fold  is formed by the pattern 3   1473  distributed to the first unit and second unit of the assist device  1410 . Accordingly to this, the pattern 3   1473  is capacitively coupled with the pattern 1   1471 , and the pattern 1   1471  and the pattern 3   1473  have influence on signal radiation. That is, in the folding status, the pattern 1   1471  and the pattern 3   1473  become main patterns, and the pattern 2   1472  becomes a dummy pattern. For example, the pattern 3   1473  can form capacitance with a conductor of a rear side of the electronic device  1400 , and generate a new resonance frequency depending on a concrete position of the pattern 3   1473 . 
         [0089]    In the exemplary embodiment described with reference to  FIG. 14 , in a case of the close status illustrated in the  FIG. 14B , the C close  is formed. At this time, the C fold  can have a value of 0, but can have any other value in accordance with cases. However, the C fold  can be designed to have a relatively very small value compared to the C close . That is, in a case of  FIG. 14B , it can be implemented that the influence of the pattern 2   1472  is dominant compared to the influence of the pattern 3   1473 . Likewise, in a case of  FIG. 14C , the C close  value may not be equal to 0, but it can be implemented that the influence of the pattern 3   1473  is dominant compared to the influence of the pattern 2   1472 . For the sake of this, design factors such as areas of the patterns  1471 ,  1472 , and  1473 , an overlapped extent thereof, positions thereof in the assist device  1410 , shapes thereof, lengths thereof, dielectric constants of other materials than the patterns  1471 ,  1472 , and  1473 , etc. can be taken into consideration. At this time, other components (e.g., a bracket, an LCD, a camera, etc.) of the electronic device  1400  can be more considered. 
         [0090]      FIG. 15  illustrates a further example of implementation of an assist device according to an exemplary embodiment of the present invention.  FIG. 15  illustrates an example in which a plurality of cover antennas are implemented. 
         [0091]    Referring to  FIG. 15 , the assist device includes a cellular sub cover antenna  1546 - 1  corresponding to a cellular sub antenna  1506 - 1 , and a wireless LAN cover antenna  1546 - 2  corresponding to a wireless LAN antenna  1506 - 2 . That is, because the electronic device can include a plurality of antennas for different bands, even the assist device can include cover antennas corresponding to respective bands. As illustrated in  FIG. 15 , the electronic device can further include a GPS antenna  1506 - 3 , a cellular main antenna  1506 - 4 , and/or a 2 nd -Generation (2G)/3 rd -Generation (3G) antenna  1506 - 5 , and even the assist device can further include corresponding cover antennas. 
         [0092]      FIGS. 16A to 16C  illustrate an example of use of an assist device according to an exemplary embodiment of the present invention.  FIGS. 16A to 16C  exemplify cover antennas applied to various platforms. 
         [0093]    Referring to  FIGS. 16A to 16C , as in  FIG. 16A , an assist device according to an exemplary embodiment of the present invention is an assist device for a smart phone  1692 , and can include at least one cover antenna. Also, as in FIG.  16 B, the assist device according to the exemplary embodiment of the present invention is an assist device for a tablet PC  1694 , and can include at least one cover antenna. Also, as in  FIG. 16C , the assist device according to the exemplary embodiment of the present invention is an assist device for a tablet type smart phone  1696 , and can include at least one cover antenna. 
         [0094]      FIG. 17  illustrates another example of use of an assist device according to an exemplary embodiment of the present invention. 
         [0095]    Referring to  FIG. 17 , the assist device can include a cover antenna  1746  for a broadcasting receiver  1782 . For example, the broadcasting receiver  1782  can be a means for receiving Digital Multimedia Broadcasting (DMB), radio, etc. Generally, a broadcasting signal belongs to a low frequency band compared to a data communication signal such as cellular communication. Accordingly, because a wavelength of the broadcasting signal is relatively long, it is general that a separate external antenna is used. But, in accordance with an exemplary embodiment of the present invention, the cover antenna  1746  can instead perform a role of an external antenna. In this case, unlike a conventional external antenna, the cover antenna  1746  according to an exemplary embodiment of the present invention has the merit of not requiring physical fastening. 
         [0096]    The broadcasting receiver  1782  operates as a means receiving a broadcasting signal and concurrently, can function as a main antenna for the broadcasting signal. In detail, the broadcasting receiver  1782  can perform a function of a feeding part enabling contact type feeding with the external antenna. Also, by forming a capacitive coupling pad pattern, the broadcasting receiver  1782  can implement non-contact type feeding with the external antenna. In more detail, the capacitive coupling pad pattern has an area of 1/100 or less compared to a frequency of the broadcasting signal, thereby implementing coupling in a near field. 
         [0097]    As an antenna for the broadcasting receiver  1782 , an audio output device such as an earphone including conductive materials can be used as an alternative antenna. In case where the alternative antenna such as the earphone and the cover antenna  1746  are concurrently installed, an electronic device can selectively use any one of them through a comparison of a reception sensitivity. Or, the electronic device can receive a broadcasting signal using all the both. In this case, a diversity gain can be obtained more. 
         [0098]      FIG. 18  illustrates antenna performance caused by an assist device according to an exemplary embodiment of the present invention.  FIG. 18  illustrates a throughput variation dependent on a transmission power.  FIG. 18  illustrates the performance at application of a Multiple Input Multiple Output (MIMO) technique using a main antenna of an electronic device and a sub antenna. 
         [0099]    Referring to  FIG. 18 , in a case of an open status, it is checked that the performance is improved compared to a non-installation status. Also, in a case of a close status and a folding status, it is checked that the same performance as the non-installation status is shown. That is, a cover antenna within the assist device according to an exemplary embodiment of the present invention can compensate the influence of the assist device or a user&#39;s handgrip. 
         [0100]    Table 1 below represents a simulation result assuming bands B13, B5, B2, and B4 defined in the Long Term Evolution (LTE) standard. 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
               
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
             
             
               
                   
                   
               
               
                   
                 Assist de- 
                   
               
               
                   
                 vice with 
                 Assist device with cover antenna 
               
             
          
           
               
                   
                 no cover 
                 Open 
                 Close 
                 Folding 
               
             
          
           
               
                 Band 
                 antenna 
                 status 
                 status 
                 status 
               
               
                   
               
             
          
           
               
                 Passive 
                 B13 re- 
                 −14.1 dBi 
                 +12.4 
                 −1.3 
                 −2.1 
               
               
                 efficiency 
                 ception 
               
               
                   
                 B5 re- 
                 −13.9 dBi 
                 +11.3 
                 −0.1 
                 +6.8 
               
               
                   
                 ception 
               
               
                   
                 B2 re- 
                 −4.35 dBi 
                 +2.8 
                 +0.7 
                 −2.7 
               
               
                   
                 ception 
               
               
                   
                 B4 re- 
                 −5.33 dBi 
                 +3.0 
                 −0.7 
                 +1.7 
               
               
                   
                 ception 
               
             
          
           
               
                 Total Isotropic Sensitiv- 
                 −84.18 dBi  
                 +5.7 
                 −0.2 
                 −1.3 
               
               
                 ity (TIS) MIMO (main + 
               
               
                 sub antenna) B13, ch 
               
               
                 5230 
               
               
                   
               
             
          
         
       
     
         [0101]    As shown in Table 1, it is shown, according to using an assist device with a cover antenna according to an exemplary embodiment of the present invention, reception sensitivity is improved in all statuses compared to when using an assist device with no cover antenna. 
         [0102]    In the aforementioned exemplary embodiments of the present invention, a first antenna included in a first unit of an assist device is capacitively coupled with an internal antenna included in an electronic device. In accordance with another exemplary embodiment of the present invention, the first antenna and the internal antenna can be physically coupled with each other. Below, the present invention describes exemplary embodiments in which the first antenna and the internal antenna are physically coupled with each other. 
         [0103]      FIG. 19  illustrates an example of components of an assist device according to another exemplary embodiment of the present invention. 
         [0104]    Referring to  FIG. 19 , the assist device consists of a first unit  1920  and a second unit  1930 . The first unit  1920 , a component of the assist device attached to the electronic device, can be a structure that includes a part of a component (e.g., a rear cover) of the electronic device or is independent from the electronic device. That is, so long as the assist device is not eliminated, a relative position relationship between the first unit  1920  and the electronic device is not changed. The first unit  1920  includes a first side  1922  and a second side  1924 . The first side  1922 , a side getting in contact with a rear side of the electronic device, can be denoted as an inner side. The second side  1924 , a side opposite to the first side  1922 , can be denoted as an outer side. 
         [0105]    Also, the first unit  1920  includes a connection module  1928 . The connection module  1928  is a physical fastening means between a first antenna included in the first unit  1920  and an internal antenna of the electronic device. The connection module  1928  forms inductance between the first antenna included in the first unit  1920  and the internal antenna of the electronic device. For example, the connection module  1928  can include a conductor for transmitting a signal. In  FIG. 19 , the connection module  1928  is positioned at a right and upper end of the first unit  1920 , but in accordance with various exemplary embodiments of the present invention, the position of the connection module  1928  can be different. Also,  FIG. 19  illustrates that the connection module  1928  has a cylinder shape, but in accordance with various exemplary embodiments of the present invention, the connection module  1928  can have a different shape. 
         [0106]    The second unit  1930  is a structure independent from the electronic device. The second unit  1930  includes a first side  1932  and a second side  1934 . The first side  1932 , a side capable of getting in contact with a front side of the electronic device, can be denoted as an inner side. The second side  1934 , a side opposite to the first side  1932 , can be denoted as an outer side. The first unit  1920  and the second unit  1930  are mutually coupled with each other by means of materials having ductility or are coupled with each other through a hinge, whereby a relative position relationship between the second unit  1930  and the electronic device can be changed. Accordingly to this, the assist device can be in an open status, a close status, and/or a folding status. The statuses of the assist device can be defined as in  FIG. 4  above. 
         [0107]      FIG. 20  illustrates an equivalent circuit of antennas included in an assist device and an electronic device according to another exemplary embodiment of the present invention. 
         [0108]    Referring to  FIG. 20 , an internal antenna  2006  and a first antenna  2026  of the assist device are physically coupled with each other by means of a connection module  2028 , and the internal antenna  2006  and a second antenna  2036  of the assist device are capacitively coupled with each other. L S1  between the internal antenna  2006  and the first antenna  2026  is an inductance value generated by the connection module  2028 . The L S1  can be maintained irrespective of a status of the assist device. C 12  between the first antenna  2026  and the second antenna  2036  is a capacitance value generated between antenna patterns physically isolated from each other, and can be changed depending on the status of the assist device. A combination of the internal antenna  2006 , the first antenna  2026 , and/or the second antenna  2036  can function as one antenna. The equivalent circuit of the antennas illustrated in  FIG. 20  is one example. Accordingly, the antennas according to an exemplary embodiment of the present invention can be implemented in different structures. 
         [0109]    Methods according to exemplary embodiments mentioned in claims or specification of the present invention can be implemented in a form of hardware, software, or a combination of hardware and software. 
         [0110]    In case where the methods are implemented by software, a computer-readable storage medium storing one or more programs (software modules) can be provided. The one or more programs stored in the computer-readable storage medium are configured to be executed by one or more processors within an electronic device. The one or more programs include instructions for enabling the electronic device to execute the methods according to the exemplary embodiments stated in the claims or specification of the present invention. 
         [0111]    This program (software module, software) can be stored in a random access memory, a non-volatile memory including a flash memory, a Read Only Memory (ROM), an Electrically Erasable Programmable Read Only Memory (EEPROM), a magnetic disc storage device, a Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs) or an optical storage device of another form, a magnetic cassette. Or, the program can be stored in a memory constructed by a combination of some or all of them. Also, each constructed memory may be included in plural as well. 
         [0112]    Further, the program can be stored in an attachable storage device accessible through a communication network such as the Internet, an intranet, a LAN, a Wide LAN (WLAN) and a Storage Area Network (SAN), or a communication network constructed by a combination of them. This storage device can connect to a device performing an exemplary embodiment of the present invention through an external port. Also, a separate storage device on the communication network can connect to a device performing an exemplary embodiment of the present invention as well. 
         [0113]    In the aforementioned concrete exemplary embodiments of the present invention, components included in the invention have been expressed in the singular form or the plural form in accordance to a proposed concrete exemplary embodiment. However, for description convenience, the expression of the singular form or plural form is selected suitable to a proposed situation, and the present invention is not limited to singular or plural components. Even a component expressed in the plural form can be constructed in the singular form, or even a constituent element expressed in the singular form can be constructed in the plural form. 
         [0114]    While a concrete exemplary embodiment has been described in a detailed description of the present invention, it is undoubted that various modifications are available without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited and defined by the described exemplary embodiment, and should be defined by not only the scope of claims described later but also equivalents to the scope of claims.