Abstract:
An antenna device includes a dielectric that has a first and a second substantially planar surfaces facing in substantially opposite directions. An inverted-L antenna is disposed at a side of the dielectric. A first conductive member forms a first loop that has a first gap. A planar side of the first loop is disposed facing the first substantially planar surface of the dielectric. A second conductive member forms a second loop that has a second gap. A planar side of the second loop is disposed facing the second substantially planar surface of the dielectric. Each of the first and second conductive members includes a plurality of member components and a plurality of switches, and each of the plurality of switches are provided between two adjacent member components to allow the plurality of member components to be electrically conducted or cut off.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY 
       [0001]    The present application is related to and claims the priority under 35 U.S.C. §119(a) of applications entitled “Antenna Device And Wireless Communication Apparatus Having The Same” filed in Japanese Patent Office on Nov. 12, 2009 and assigned Serial No. 2009-258646, Nov. 12, 2009 and assigned Serial No. 2009-258647, and filed in Korean Intellectual Property Office on Sep. 17, 2010 and assigned Serial No. 10-2010-0091687, the contents of which are hereby incorporated by reference. 
       TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present invention relates to an antenna device and a wireless communication apparatus having the same and, more particularly, to an antenna device used for a mobile communication terminal and a wireless communication apparatus having the same. 
       BACKGROUND OF THE INVENTION 
       [0003]    A current wireless communication apparatus has a wireless communication function that corresponds to a plurality of wireless communication systems, and a small-sized antenna or an antenna that operates in a plurality of frequency bands or a wide range is required. 
         [0004]    In an antenna device that operates in a plurality of frequency bands, a tunable antenna changes a frequency band. For example, in International Publication pamphlet No. 07/042,615, an adjustment circuit obtained by combining conductive lines with different lengths is installed at a power supply part of a monopole antenna, resulting in an antenna device that changes a frequency band. Furthermore, in JP-T-2009-510900, a selection circuit connected to a parasitic element of an antenna device is switched to change capacitive coupling with a monopole antenna, resulting in a change in a resonant frequency. In addition, an attempt has been made to achieve an antenna that operates in a wide band by using a SRR (Split Ring Resonator). Because the SRR has been known as an element of a meta-material and is a structure that exhibits material characteristics (negative permeability) that do not exist naturally, research has been conducted in order to obtain a magnetic response at a desired frequency. For example, in U.S. Pat. No. 6,970,137, wide band characteristics are achieved using a PIFA (Planar Inverted-F Antenna) obtained by inserting a dielectric including a plurality of SRRs therein between a ground conductor and an antenna conductor. 
       SUMMARY OF THE INVENTION 
       [0005]    In the tunable antenna according to the conventional art, the conductive lines with the different lengths are switched using a switch, resulting in a change in a frequency band. However, conductive lines are required corresponding to the number of variable frequency bands. Therefore, when the number of variable frequency bands increases, because the structure of the antenna is increased, the antenna may not be fabricated in a small size. Furthermore, even when the selection circuit is connected to the parasitic element and switched using a switch, resulting in a change in a frequency band, when the number of variable frequency bands increases, because it is necessary to increase the number of parasitic elements, the antenna may not be fabricated in a small size due to the increase in the structure of the antenna. 
         [0006]    To address the above-discussed deficiencies of the prior art, it is a primary object to provide an antenna device that can be fabricated in a small size without the increase in the structure thereof even if the number of frequency bands used increases, and can easily change a resonant frequency in a desired frequency band. 
         [0007]    Also, in U.S. Pat. No. 6,970,137, because the plurality of SRRs are disposed in the dielectric block constituting the antenna, the structure thereof is complicated and the dielectric block may not be easily manufactured. Furthermore, because the plurality of SRRs are disposed in the dielectric block, it is difficult to adjust the length of each SRR, an interval among the SRRs and the like, and cost may increase in order to manufacture an antenna with desired performance. In addition, the SRR operates at a frequency at which the length of a conductor is close to half the wavelength. Therefore, when determining the material characteristics of the dielectric block or the dimensions of the SRR in the antenna configuration disclosed in U.S. Pat. No. 6,970,137, the SRR may not operate in a desired frequency band. 
         [0008]    Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and the present invention provides an antenna device and a wireless communication apparatus that can be fabricated in a small size by using material characteristics around the resonant frequency of the SRR, and can operate in a desired frequency band. 
         [0009]    In accordance with an aspect of the present invention, an antenna device includes a dielectric that has a first and a second surfaces facing in substantially opposite directions. An inverted-L antenna is disposed at a side of the dielectric. A first conductive member forms a first loop that has a first gap. A planar side of the first loop is disposed facing the first surface of the dielectric. A second conductive member forms a second loop that has a second gap. A planar side of the second loop is disposed facing the second substantially planar surface of the dielectric. Each of the first and second conductive members includes a plurality of member components and a plurality of switches. And each of the plurality of switches are provided between two adjacent member components to allow the plurality of member components to be electrically conducted or cut off. According to the antenna device, in accordance with an embodiment of the present invention, a resonant frequency may be easily changed in a desired frequency band. 
         [0010]    Furthermore, in the antenna device in accordance with an embodiment of the present invention, each of the first and second gaps may form an opening in the first and second loops of the first and second conductive members, respectively. A length of each of the first and second conductive members may form an inductance component. A size of the opening may form a capacitance component. The first and second conductive members may form an LC resonance circuit including the inductance component and the capacitance component. And the plurality of switches may allow the plurality of member components to be electrically conducted or cut off through an ON/OFF operation to change a number of connections, through which the plurality of member components are connected to each other, for each conductive member, resulting in a change in the inductance component of the first and second conductive members. According to the antenna device in accordance with an embodiment of the present invention, the antenna device may operate in a desired frequency band. 
         [0011]    Furthermore, the antenna device in accordance with an embodiment of the present invention may further include a control unit that controls the ON/OFF operation of each switch according to a wireless communication frequency band used to change the inductance component of the first and second conductive members. The control unit may detect a frequency of a wireless communication signal and control the ON/OFF operation of each switch according to the detected frequency. According to the antenna device in accordance with an embodiment of the present invention, the antenna device may be automatically shifted to a desired frequency band. 
         [0012]    Furthermore, in the antenna device in accordance with an embodiment of the present invention, the plurality of switches may allow the plurality of member components to be electrically conducted or cut off. According to the antenna device in accordance with an embodiment of the present invention, the ON/OFF operation of each switch may be performed at a high speed, and noise may be reduced. 
         [0013]    Furthermore, in the antenna device, in accordance with an embodiment of the present invention, the first conductive member may be bonded to the first surface, and the second conductive member is bonded to the second surface of the dielectric. According to the antenna device in accordance with an embodiment of the present invention, the antenna device may easily adapt with design modification. 
         [0014]    Furthermore, in the antenna device in accordance with an embodiment of the present invention, the first and second conductive members may be formed on the first and second surfaces of the dielectric, respectively, by using an etching method. According to the antenna device in accordance with an embodiment of the present invention, the antenna device may easily adapt with design modification. 
         [0015]    Furthermore, in the antenna device in accordance with an embodiment of the present invention, the dielectric may have a thin plate shape. According to the antenna device in accordance with an embodiment of the present invention, the antenna device may be easily mounted in a wireless communication apparatus and such. 
         [0016]    A wireless communication apparatus in accordance with an embodiment of the present invention includes the above-described antenna device. The wireless communication apparatus, in accordance with an embodiment of the present invention, may easily adapt with various communication schemes. 
         [0017]    In accordance with an aspect of the present invention, an antenna device includes a dielectric that includes a first and a second surfaces facing in substantially opposite directions. An inverted-L antenna may be disposed at a side of the dielectric. A first conductive member may form a first loop that has a first gap. A planar side of the first loop may be disposed facing the first surface of the dielectric. A second conductive member may form a second loop that has a second gap. A planar side of the second loop may be disposed facing the second surface of the dielectric. According to the antenna device in accordance with an embodiment of the present invention, it may be possible to achieve a wavelength shortening effect which is larger than a wavelength shortening effect due to the material constant. 
         [0018]    Furthermore, in the antenna device in accordance with an embodiment of the present invention, each of the first and second gaps may form an opening in the first and second loops of the first and second conductive members, respectively. A length of each of the first and second conductive members may form an inductance component. A size of the opening may form a capacitance component. The plurality of conductive members may form an LC resonance circuit including the inductance component and the capacitance component. And at least one of the length of each of the first and second conductive members and the size of the opening may be adjusted to control a resonant frequency of the LC resonance circuit. According to the antenna device in accordance with an embodiment of the present invention, it may be possible to easily achieve wide band characteristics by which an operation in a desired frequency band is possible. 
         [0019]    Furthermore, in the antenna device in accordance with an embodiment of the present invention, relative positions of the first and second conductive members disposed facing the dielectric may be changed to control the capacitance component. According to the antenna device in accordance with an embodiment of the present invention, it may be possible to easily achieve wide band characteristics by which an operation in a desired frequency band is possible. 
         [0020]    Furthermore, in the antenna device in accordance with an embodiment of the present invention, a relative distance between the first and second conductive members may be changed according to thickness of the dielectric to control the capacitance component. According to the antenna device in accordance with an embodiment of the present invention, it may be possible to easily achieve wide band characteristics by which an operation in a desired frequency band is possible. 
         [0021]    Furthermore, in the antenna device in accordance with an embodiment of the present invention, relative positions of the first and second conductive members disposed facing the dielectric and the inverted-L antenna may be changed to control the capacitance component. According to the antenna device in accordance with an embodiment of the present invention, it may be possible to easily achieve wide band characteristics by which an operation in a desired frequency band is possible. 
         [0022]    Furthermore, in the antenna device in accordance with an embodiment of the present invention, a length of each of the first and second conductive members disposed facing the dielectric and a length of the inverted-L antenna are changed to control the inductance component. According to the antenna device in accordance with an embodiment of the present invention, it may be possible to easily achieve wide band characteristics by which an operation in a desired frequency band is possible. 
         [0023]    Furthermore, in the antenna device in accordance with an embodiment of the present invention, the first and second conductive members may be formed on the first and second surfaces of the dielectric by using an etching method. According to the antenna device in accordance with an embodiment of the present invention, the antenna device may easily cope with design modification. 
         [0024]    Furthermore, in the antenna device in accordance with an embodiment of the present invention, the first and second conductive members are bonded to the first and second surfaces of the dielectric, respectively. According to the antenna device in accordance with an embodiment of the present invention, the antenna device may easily cope with design modification. 
         [0025]    Furthermore, in the antenna device in accordance with an embodiment of the present invention, the dielectric may have a thin plate shape. According to the antenna device in accordance with an embodiment of the present invention, the antenna device may be easily mounted in a wireless communication apparatus and such. 
         [0026]    A wireless communication apparatus in accordance with an embodiment of the present invention includes the above-described antenna device. The wireless communication apparatus in accordance with an embodiment of the present invention may easily adapt with various communication schemes. 
         [0027]    Before undertaking the DETAILED DESCRIPTION OF THE INVENTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts: 
           [0029]      FIG. 1  is a plan view that illustrates the outline of an antenna device in accordance with an embodiment of the present invention; 
           [0030]      FIG. 2  illustrates a perspective view of an entire configuration of an antenna device in accordance with an embodiment of the present invention; 
           [0031]      FIGS. 3A and 3B  illustrates plan views of a configuration example of SRRs of an antenna device in accordance with an embodiment of the present invention, wherein  FIG. 3A  illustrates plan view of the configuration example of a SRR formed on the front surface of a dielectric, and  FIG. 3B  illustrates a plan view of the configuration example of a second SRR formed on the rear surface of the dielectric; 
           [0032]      FIG. 4  illustrates permittivity characteristics of the antenna device illustrated in  FIG. 2 ; 
           [0033]      FIG. 5  illustrates permeability characteristics of the antenna device illustrated in  FIG. 2 ; 
           [0034]      FIG. 6  illustrates the circuit configuration of a wireless communication apparatus provided with an antenna device in accordance with an embodiment of the present invention; 
           [0035]      FIG. 7  illustrates an example of VSWR frequency characteristics when a LTE frequency band of the antenna device illustrated in  FIG. 2  is changed; 
           [0036]      FIG. 8  illustrates an example of VSWR frequency characteristics when a GSM frequency band of the antenna device illustrated in  FIG. 2  is changed; 
           [0037]      FIGS. 9A to 9C  illustrate plan views of other shapes of a SRR of an antenna device in accordance with an embodiment of the present invention, wherein  FIG. 9A  illustrates a plan view of the shape of a SRR with an opening formed by removing a part of a polygonal shape, and  FIG. 9B  illustrates a diagram of the shape of a SRR with an opening formed by removing a part of a rectangular shape, and  FIG. 9C  illustrates a diagram of the shape of a SRR with an opening formed by removing a part of a ring shape; 
           [0038]      FIG. 10  illustrates a perspective view of the configuration of main elements of an antenna device in accordance with an embodiment of the present invention; 
           [0039]      FIG. 11  illustrates a perspective view of the entire configuration of an antenna device in accordance with an embodiment of the present invention; 
           [0040]      FIG. 12  illustrates a diagram of permittivity characteristics of the antenna device illustrated in  FIG. 10 ; 
           [0041]      FIG. 13  illustrates a diagram of permeability characteristics of the antenna device illustrated in  FIG. 10 ; 
           [0042]      FIG. 14  illustrates a diagram of VSWR frequency characteristics of the antenna device illustrated in  FIG. 10 ; 
           [0043]      FIG. 15  illustrates a perspective view of the entire configuration of an antenna device in accordance with an embodiment of the present invention; 
           [0044]      FIGS. 16A to 16C  illustrate plan views of other shapes of a SRR of an antenna device in accordance with an embodiment of the present invention, wherein  FIG. 16A  illustrates the shape of a SRR with an opening formed by removing a part of a polygonal shape, and  FIG. 16B  illustrates the shape of a SRR with an opening formed by removing a part of a rectangular shape, and  FIG. 16C  illustrates the shape of a SRR with an opening formed by removing a part of a ring shape; and 
           [0045]      FIG. 17  schematically illustrates the configuration of a wireless communication apparatus provided with an antenna device in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0046]      FIGS. 1 through 17 , discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged communication device. Furthermore, various specific definitions found in the following description are provided only to help the general understanding of the present invention, and it is apparent to those skilled in the art that the present invention can be implemented without such definitions. Further, in the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. 
         [0047]      FIG. 1  illustrates a plan view of the outline of an antenna device in accordance with an embodiment of the present invention. The object of the antenna device in accordance with the embodiment of the present invention is to dispose a switch on a conductor constituting a SRR (Split Ring Resonator) by using material characteristics around the resonant frequency of the SRR and to turn on/off the switch, resulting in the miniaturization of the antenna device and a change in the resonant frequency of a desired frequency band. The SRR is a structure that includes a metal (a conductive member) in which at least a part thereof is separated, and produces the characteristics of the SRR, which will be described later. 
         [0048]    The antenna device  100  illustrated in  FIG. 1  includes a first SRR  101 , a second SRR  102 , a dielectric  103 , an element conductor  104 , a power supply point  105 , and a ground conductor  106 . The element conductor  104  has an inverted-L shape and constitutes an inverted-L antenna. Furthermore, the element conductor  104  is connected to the ground conductor  106  through the power supply point  105  and the dielectric  103  is disposed between the ground conductor  106  and the element conductor  104 . The dielectric  103  may have a thin plate shape, and the first SRR  101  and the second SRR  102  are disposed facing one surface and another surface of the dielectric  103 , respectively. Each of the first SRR  101  and the second SRR  102  is a structure that includes a metal (a conductive member) in which at least a part thereof is separated, and produces the characteristics of the SRR, which will be described later. 
         [0049]    The first SRR  101  and the second SRR  102  have a first opening  101   a  and a second opening  102   a , which are formed by removing a part of a rectangle, respectively. However, the present invention is not limited to the rectangle. For example, the first SRR  101  and the second SRR  102  may also have a shape which is formed by removing at least a part of a polygonal or ring shape. The first SRR  101  and the second SRR  102  are disposed at opposite sides with the dielectric  103  interposed between them while they are misaligned from each other. For example, when the first opening  101   a  of the first SRR  101  is located at a right side of the dielectric  103 , the second opening  102   a  of the second SRR  102  is located at a left side of the dielectric  103 . Furthermore, the first SRR  101  and the second SRR  102  may have the same shape or different shapes from each other. 
         [0050]      FIG. 2  illustrates a perspective view of an entire configuration of an antenna device in accordance with an embodiment of the present invention. A dielectric  203  of the antenna device  200  has a rectangular thin plate shape, and a first SRR  201  and a second SRR  202  are disposed on the front surface and the rear surface of the dielectric  203 , respectively. As illustrated in  FIG. 2 , the first SRR  201  and the second SRR  202  have a first opening  201   a  and a second opening  202   a , which are formed by removing one side of a rectangle, respectively. The first SRR  201  and the second SRR  202  have the same shape and are disposed at opposite sides with the dielectric  103  interposed between them. 
         [0051]      FIGS. 3A and 3B  illustrate plan views of a configuration example of the first SRR  201  and the second SRR  202  of the antenna device  200  illustrated in  FIG. 2 , wherein  FIG. 3A  illustrates a plan view of the configuration example of the first SRR  201  formed on the front surface of the dielectric  203 , and  FIG. 3B  illustrates a plan view of the configuration example of the second SRR  202  formed on the rear surface of the dielectric  203 . 
         [0052]    As illustrated in  FIGS. 2 and 3 , the first SRR  201  and the second SRR  202  include a plurality of switches disposed on conductors constituting the first SRR  201  and the second SRR  202 , respectively. The switches in accordance with the embodiment of the present invention, for example, may be formed of a switch such as a MEMS switch or a relay, or a variable capacitor element such as a varicap diode. Furthermore, the switches in accordance with the embodiment of the present invention allow the conductors to be mechanically or electrically conducted or cut off at portions, at which the switches are disposed in the first SRR  201  and the second SRR  202 , through a switching ON/OFF operation. With respect to the switches for allowing the conductors to be electrically conducted or cut off, the switching ON/OFF operation can be performed at a high speed and noise can be reduced. The operation and circuit configuration of the switch, in accordance with the embodiment of the present invention, will be described in detail later. 
         [0053]    In accordance with the embodiment of the present invention, as illustrated in  FIG. 3A , the first SRR  201  includes a plurality of members  201   b  to  201   h , a switch SW 1   a  is disposed between the members  201   b  and  201   c , a switch SW 2   a  is disposed between the members  201   c  and  201   d , a switch SW 3   a  is disposed between the members  201   d  and  201   e , a switch SW 3   b  is disposed between the members  201   e  and  201   f , a switch SW 2   b  is disposed between the members  201   f  and  201   g , and a switch SW 1   b  is disposed between the members  201   g  and  201   h . The six switches SW 1   a , SW 1   b , SW 2   a , SW 2   b , SW 3   a  and SW 3   b  allow the plurality of members  201   b  to  201   h  to be conducted or cut off through the switching ON/OFF operation, and change the number of connections among the members. 
         [0054]    Furthermore, in accordance with the embodiment of the present invention, as illustrated in  FIG. 3B , the second SRR  202  includes a plurality of members  202   b  to  202   f , a switch SW 4   a  is disposed between the members  202   b  and  202   c , a switch SW 5   a  is disposed between the members  202   c  and  202   d , a switch SW 5   b  is disposed between the members  202   d  and  202   e , and a switch SW 4   b  is disposed between the members  202   e  and  202   f . The four switches SW 4   a , SW 4   b , SW 5   a  and SW 5   b  allow the plurality of members  202   b  to  202   f  to be conducted or cut off through the switching ON/OFF operation, and change the number of connections among the members. 
         [0055]    In addition, in accordance with the embodiment of the present invention, as illustrated in  FIGS. 3A and 3B , on the two linear conductors extending in the Y direction of the first SRR  201 , the switch SW 1   b  may be disposed facing the switch SW 1   a , the switch SW 2   b  may be disposed facing the switch SW 2   a , and the switch SW 3   b  may be disposed facing the switch SW 3   a . On the two linear conductors extending in the Y direction of the second SRR  202 , the switch SW 4   b  may be disposed facing the switch SW 4   a  and the switch SW 5   b  may be disposed facing the switch SW 5   a . Moreover, in accordance with the embodiment of the present invention, the number and positions of switches to be disposed may be appropriately changed according to the specifications thereof. 
         [0056]    Next, the characteristics of the antenna device in accordance with the embodiment of the present invention will be described with reference to  FIGS. 4 and 5 .  FIG. 4  illustrates a diagram of permittivity characteristics of the antenna device  200  illustrated in  FIG. 2 , and  FIG. 5  illustrates a diagram of permeability characteristics of the antenna device  200  illustrated in  FIG. 2 .  FIGS. 4 and 5  illustrate characteristics of real parts and imaginary parts of permittivity and permeability, respectively. Hereinafter, the general characteristics of the SRR regarding such characteristics will be described. 
         [0057]    Characteristics of SRR 
         [0058]    In general, the SRR includes two concentric circular metal rings that include “Splits” formed on a part thereof. This is a metal structure called a “double ring SRR” and this one element operates as an artificial atom showing a magnetic response. In this structure, an inductance component L may be provided at a ring part and a capacitance component C may be provided between the two rings. If electromagnetic waves (incident magnetic field) with a magnetic field component perpendicular to a plane including the rings are incident, an induction current J producing a resistance magnetic field opposing the incident magnetic field is induced on the rings according to the principle of magnetic field induction. Because the induction current flows along the rings but is cut off by the splits installed at a part of the rings, positive charge and negative charge with the same amount are accumulated between the inner and outer rings. The charges flow from the inner ring to the outer ring (or from the outer ring to the inner ring) through the capacitance between the rings, such that an LC resonance closed circuit is formed in the structure of the double ring SRR. At this time, the resonant frequency of the SRR is expressed by Equation 1 below using C and L of the structure. 
         [0000]    
       
         
           
             
               
                 
                   
                     f 
                     0 
                   
                   = 
                   
                     1 
                     
                       2 
                        
                       π 
                        
                       
                         CL 
                       
                     
                   
                 
               
               
                 
                   [ 
                   
                     Eqn 
                     . 
                     
                         
                     
                      
                     1 
                   
                   ] 
                 
               
             
           
         
       
     
         [0059]    A large induction current is induced around the resonant frequency and a larger resistance magnetic field is generated, resulting in a significant change in macro-permeability of the meta-material including the SRR. If electromagnetic waves with a frequency near the resonant frequency is incident, the electromagnetic waves are resonantly absorbed in the SRR. At this time, the imaginary part of the permeability corresponding to the absorption is increased and simultaneously the real part of the permeability is also changed. Variation of the real part is increased as variation of the imaginary part becomes larger, that is, as the Q value of the SRR becomes larger. If proper conditions are established, negative permeability may be achieved toward a high frequency side of the resonant frequency. 
         [0060]    According to the SRR as described above, the magnetic-driving LC resonance circuit operates according to the operation principle thereof, and it is possible to produce a meta-material that exhibits a magnetic response at a desired operation frequency according to the design of a resonator. 
         [0061]    Next, detailed characteristics of the antenna device using the characteristics of the above-described SRR in accordance with the embodiment of the present invention will be described. 
         [0062]    The antenna device  200  illustrated in  FIGS. 2 and 3  is formed using the characteristics of the SRR. For example, the antenna device  200  has the permittivity characteristics illustrated in  FIG. 4  and the permeability characteristics illustrated in  FIG. 5 , which are the characteristics of the SRR. Adjustment conditions of the configuration for obtaining a wavelength shortening effect around a desired frequency band in the antenna device  200  having such characteristics will be described below. 
         [0063]    An inverted-L antenna at a frequency at which the length thereof is close to one quarter of the wavelength on a free space. Therefore, when an inverted-L element conductor is formed on a dielectric, the wavelength shortening effect is affected by a material constant of the dielectric. 
         [0064]    In the antenna device  200  illustrated in  FIG. 2 , the first SRR  201  and the second SRR  202  are disposed between the inverted-L element conductor  204  formed on the dielectric  203  and the ground conductor  206 , such that a large wavelength shortening effect can be achieved by multiplying the material constant of the dielectric by the variation of effective permeability around the resonant frequency of the SRR. 
         [0065]    In general, a phase speed Vp is expressed by Equation 2. 
         [0000]    
       
         
           
             
               
                 
                   
                     V 
                     P 
                   
                   = 
                   
                     C 
                     
                       ɛγμγ 
                     
                   
                 
               
               
                 
                   [ 
                   
                     Eqn 
                     . 
                     
                         
                     
                      
                     2 
                   
                   ] 
                 
               
             
           
         
       
     
         [0066]    In Equation 2, c denotes the velocity of light in a vacuum state, μγ denotes specific permeability of a medium, and ∈γ denotes relative permittivity of the medium. That is, since a wavelength shortening effect is obtained according to the material constant as expressed by Equation 3, it is possible to obtain a wavelength shortening effect by multiplying the material constant of the dielectric by the variation of the effective permeability around the resonant frequency of the SRR. 
         [0000]    
       
         
           
             
               
                 
                   1 
                   
                     ɛγμγ 
                   
                 
               
               
                 
                   [ 
                   
                     Eqn 
                     . 
                     
                         
                     
                      
                     3 
                   
                   ] 
                 
               
             
           
         
       
     
         [0067]    Consequently, according to the antenna configuration illustrated in  FIG. 2 , the lengths of the conductors of the first SRR  201  and the second SRR  202  are adjusted, such that the antenna resonates around the frequency band of an LTE and the effective permeability significantly changes around the frequency. LTE is one of high speed data communication specifications for a cell phone, called “Long Term Evolution” in 3GPP, which is a standardization body that supports WCDMA (a 3rd cell phone scheme) and indicates a next generation communication system that is being standardized. For example, LTE uses a frequency of 700 MHz. 
         [0068]    Next, the circuit configuration of a wireless communication apparatus provided with an antenna device with the above-described characteristics in accordance with the embodiment of the present invention will be described with reference to  FIG. 6 .  FIG. 6  illustrates a block diagram of the circuit configuration of the wireless communication apparatus  300  provided with the antenna device  303 . 
         [0069]    The wireless communication apparatus  300  in accordance with the embodiment of the present invention includes the antenna device  303  that includes a first SRR  301  and a second SRR  302 , a communication unit  304 , an operation unit  305 , a display unit  306 , and a control unit  307 . 
         [0070]    The communication unit  304  transmits/receives various control signals and data signals to/from an external communication system or a base station (not shown) through the antenna device  303  under the control of the control unit  307 , and simultaneously outputs received information to the control unit  307 . The control unit  307  includes a CPU, a ROM, a RAM, an interface, through which signals are input/output to/from the communication unit  304 , the operation unit  305  and the display unit  306 , and such, and controls the entire operation of the wireless communication apparatus  300  based on control programs stored in the ROM. For example, the control unit  307  receives signals from the operation unit  305 , displays a predetermined image on the display unit  306 , and transmits/received data to/from the communication unit  304 . 
         [0071]    Furthermore, the control unit  307  detects a frequency of a wireless communication signal received in the communication unit  304  and controls the ON/OFF operations of a plurality of switches disposed in the first SRR  301  and the second SRR  302  according to the detected frequency. The plurality of switches are connected to the control unit  307  through a plurality of lines L 1  and L 2  and perform the ON/OFF operations according to a control signal of the control unit  307 . In the embodiment, the control unit  307  controls the ON/OFF operations of the plurality of switches disposed in the first SRR  301  when the frequency of the wireless communication signal corresponding to the LTE is detected and controls the ON/OFF operations of the plurality of switches disposed in the second SRR  302  when the frequency of the wireless communication signal corresponding to a GSM (Global System for Mobile Communication) is detected, thereby adjusting VSWR (Voltage Standing Wave Ratio) frequency characteristics of the antenna  303 , which will be described later, to frequency characteristics corresponding to the LTE or the GSM. The GSM is one of the wireless communication schemes used for a cell phone, and uses a frequency band of 850 MHz, 900 MHz and such. 
         [0072]    Next, the operation of the antenna device  303  in the wireless communication apparatus  300  illustrated in  FIG. 6  will be described with reference to  FIGS. 7 and 8 .  FIG. 7  is a diagram illustrating VSWR characteristics when the antenna device  303  operates in a frequency band corresponding to LTE, and  FIG. 8  is a diagram illustrating VSWR characteristics when the antenna device  303  operates in a frequency band corresponding to GSM. 
         [0073]    First, the operation of the antenna device  303  in LTE frequency band will be described with reference to  FIG. 7 . Operations A to D illustrated in  FIG. 7  are operations of the switches disposed in the first SRR  301 . Furthermore, it is assumed that all switches disposed in the second SRR  302  are turned on when the switches disposed in the first SRR  301  operate. 
         [0074]    Operation A illustrated in  FIG. 7  is an operation when all switches SW 1   a , SW 1   b , SW 2   a , SW 2   b , SW 3   a  and SW 3   b  disposed on the conductor of the first SRR  301  are turned on. At this time, the length of the conductor of the first SRR  301  is the longest. Referring to the graph illustrated in  FIG. 7 , in Operation A, the resonant frequency band of the antenna device  303  is set to the lowest frequency side as compared with the operations B to D. 
         [0075]    Operation B illustrated in  FIG. 7  is an operation when the switches SW 1   a  and SW 1   b  disposed on the conductor of the first SRR  301  are turned off and the switches SW 2   a , SW 2   b , SW 3   a  and SW 3   b  are turned on. At this time, the length of the conductor of the first SRR  301  is shorter than that of the operation A. Referring to the graph illustrated in  FIG. 7 , in Operation B, the resonant frequency band of the antenna device  303  is shifted to a higher frequency as compared with Operation A. 
         [0076]    Operation C illustrated in  FIG. 7  is an operation when the switches SW 1   a , SW 1   b , SW 2   a  and SW 2   b  disposed on the conductor of the first SRR  301  are turned off and the switches SW 3   a  and SW 3   b  are turned on. At this time, the length of the conductor of the first SRR  301  is shorter than that of Operations A and B. Referring to the graph illustrated in  FIG. 7 , Operation C, the resonant frequency band of the antenna device  303  is shifted to a higher frequency side as compared with Operation B. 
         [0077]    Operation D illustrated in  FIG. 7  is an operation when all switches SW 1   a , SW 1   b , SW 2   a , SW 2   b , SW 3   a  and SW 3   b  disposed on the conductor of the first SRR  301  are turned off. At this time, the length of the conductor of the first SRR  301  is the shortest. Referring to the graph illustrated in  FIG. 7 , in Operation D, the resonant frequency band of the antenna device  303  is shifted to the highest frequency side as compared with Operations A to C. 
         [0078]    Through the operation of the switches illustrated in Operations A to D, the length of the first SRR  301  is gradually shortened to reduce an inductance component, such that the resonant frequency band of the antenna device  303  can be changed to a high frequency side from a low frequency side in the LTE frequency band. 
         [0079]    The operation of the antenna device  303  in the GSM frequency band will now be described with reference to  FIG. 8 . Operations E to G illustrated in  FIG. 8  are operations of the switches disposed in the second SRR  302 . Furthermore, it is assumed that all switches disposed in the first SRR  301  are turned on when the switches disposed in the second SRR  302  operate. 
         [0080]    Operation E illustrated in  FIG. 8  is an operation when all switches SW 4   a , SW 4   b , SW 5   a  and SW 5   b  disposed on the conductor of the second SRR  302  are turned off. At this time, the length of the conductor of the second SRR  302  is the shortest. Referring to the graph illustrated in  FIG. 8 , in Operation E, the resonant frequency band of the antenna device  303  is set to the highest frequency side as compared with Operations F and G. 
         [0081]    Operation F illustrated in  FIG. 8  is an operation when the switches SW 4   a  and SW 4   b  disposed on the conductor of the second SRR  302  are turned off and the switches SW 5   a  and SW 5   b  are turned on. At this time, the length of the conductor of the second SRR  302  is longer than that of Operation E. Referring to the graph illustrated in  FIG. 8 , in Operation F, the resonant frequency band of the antenna device  303  is shifted to a low frequency side as compared with Operation E. 
         [0082]    Operation G illustrated in  FIG. 8  is an operation when all switches SW 4   a , SW 4   b , SW 5   a  and SW 5   b  disposed on the conductor of the second SRR  302  are turned on. At this time, the length of the conductor of the second SRR  302  is the longest. Referring to the graph illustrated in  FIG. 8 , in Operation G, the resonant frequency band of the antenna device  303  is shifted to the lowest frequency side as compared with Operations E and F. 
         [0083]    Through the operation of the switches illustrated in Operations E to G, the length of the second SRR  302  is gradually lengthened to increase an inductance component, such that the resonant frequency band of the antenna device  303  can be changed to a low frequency side from a high frequency side in the GSM frequency band. 
         [0084]    Consequently, the ON/OFF operations of the switches disposed on the conductor of the first SRR  301  are simply switched, such that the VSWR characteristics can be easily changed in the LTE frequency band. Furthermore, the ON/OFF operations of the switches disposed on the conductor of the second SRR  302  are simply switched, such that the VSWR characteristics can be easily changed in the GSM frequency band. As a result, it is possible to adjust the resonant frequency in an independent desired frequency band in the first SRR  301  and the second SRR  302 , which are formed on one surface and the other surface of the dielectric. 
         [0085]    According to the embodiment of the present invention as described above, the switches are disposed on the conductor of the SRR and, as the ON/OFF of the switches are switched, the resonant frequency can be changed in a desired frequency band. Furthermore, because the switches are disposed on the conductor of the SRR and the ON/OFF of the switches are switched, even if the number of frequency bands of a wireless communication system increases, the structure of the antenna device is not increased and a small-sized wireless communication apparatus applicable to a plurality of wireless communication systems can be provided. 
         [0086]    In addition, the operation of the wireless communication apparatus  300  of the embodiment has been described, in which the ON/OFF operations of the switches disposed in the first SRR  301  and the second SRR  302  are switched, such that the resonant frequency is changed in the LTE frequency band or the GSM frequency band. By using the operation for changing the resonant frequency, the wireless communication apparatus  300  can also perform an auto-tuning operation. For example, in an initial state, all switches disposed in the first SRR  301  and the second SRR  302  are turned on or off. The control unit  307  switches the ON/OFF operations of the switches to gradually change the lengths of the conductors of the first SRR  301  and the second SRR  302 , such that the resonant frequency is gradually shifted to a low frequency side or a high frequency side, resulting in the automatic tuning to a wireless communication signal. 
         [0087]    Next, other shapes of the SRR of the antenna device in accordance with the embodiment of the present invention will be described with reference to  FIGS. 9A to 9C .  FIG. 9A  illustrates a plan view of the shape of a SRR  401  that includes an opening  401   a  formed by removing a part of a polygonal shape,  FIG. 9B  illustrates a plan view of the shape of a SRR  402  that includes an opening  402   a  formed by removing a part of a rectangular shape, and  FIG. 9C  illustrates a plan view of the shape of a SRR  403  that includes an opening  403   a  formed by removing a part of a ring shape. The present invention is not limited to the above shapes and may be applied to if any shape that can realize the characteristics of the SRR as described above. Furthermore, as illustrated in  FIG. 9A , the SRR  401  includes a plurality of members  401   b  to  401   f , a switch SW 7   a  is disposed between the members  401   b  and  401   c , a switch SW 6   a  is disposed between the members  401   c  and  401   d , a switch SW 6   b  is disposed between the members  401   d  and  401   e , and a switch SW 7   b  is disposed between the members  401   e  and  401   f . As illustrated in  FIG. 9B , the SRR  402  includes a plurality of members  402   b  to  402   f , a switch SW 9   a  is disposed between the members  402   b  and  402   c , a switch SW 8   a  is disposed between the members  402   c  and  402   d , a switch SW 8   b  is disposed between the members  402   d  and  402   e , and a switch SW 9   b  is disposed between the members  402   e  and  402   f . As illustrated in  FIG. 9C , the SRR  403  includes a plurality of members  403   b  to  403   f , a switch SW 11   a  is disposed between the members  403   b  and  403   c , a switch SW 10   a  is disposed between the members  403   c  and  403   d , a switch SW 10   b  is disposed between the members  403   d  and  403   e , and a switch SW 11   b  is disposed between the members  403   e  and  403   f . In this way, similarly to the antenna device  303  illustrated in  FIG. 6 , the SRRs  401  to  403  illustrated in  FIG. 9  are used for the antenna device, resulting in a change in the resonant frequency. Furthermore, the number and positions of switches disposed may be appropriately changed according to the specifications thereof. 
         [0088]    In addition, because the antenna device  200 , illustrated in  FIG. 2  in accordance with the embodiment of the present invention, can be realized by forming the first SRR  201  and the second SRR  202  on the front surface and the rear surface of the dielectric  203  located between the inverted-L element conductor  204  and the ground conductor  206 , the antenna device  200  can be manufactured in a simple manner. For example, the first SRR  201  and the second SRR  202  may be formed by etching the front surface and the rear surface of the dielectric  203 , or the first SRR  201  and the second SRR  202  may be simply bonded to the front surface and the rear surface of the dielectric  203 . Through such a simple manufacturing method, because it is possible to easily adapt with the situation in which a design is changed to allow the antenna device  200  to operate in a desired frequency band, the manufacturing cost can be reduced. 
         [0089]    Moreover, the dielectric  203  in accordance with the embodiment of the present invention may be formed of a flexible dielectric film and the like. When the dielectric  203  is manufactured using a flexible dielectric film substrate, because the dielectric  203  can be bent, the dielectric  203  can be easily mounted in a wireless communication apparatus. Furthermore, in addition to the dielectric  203 , the element conductor  204  or the ground conductor  206  may be formed using a flexible material. 
         [0090]    In accordance with the embodiment of the present invention as described above, the SRRs are disposed on the front surface and the rear surface of the dielectric located between the inverted-L element conductor and the ground conductor, the switches are disposed on the conductors of the SRRs, and the ON/OFF operations of the switches are switched, such that the resonant frequency can be changed in a desired frequency band. In addition, even if the number of frequency bands of a wireless communication system used increases, the structure of the antenna device is not increased and a small-sized wireless communication apparatus applicable to a plurality of wireless communication systems can be provided. 
         [0091]    Hereinafter, an antenna device operating in a wide band in accordance with an embodiment of the present invention will be described with reference to the accompanying drawings. 
         [0092]      FIG. 10  illustrates a perspective view of the configuration of main elements of the antenna device  1000  in accordance with an embodiment of the present invention.  FIG. 11  is a perspective view illustrating the entire configuration of the antenna device illustrated in  FIG. 10 . A dielectric  1003  in the antenna device  1000  has a rectangular thin plate shape, and a first SRR  1001  and a second SRR  1002  are disposed on the front surface and the rear surface of the dielectric. As illustrated in  FIG. 10 , the first SRR  1001  and the second SRR  1002  have a first opening  1001   a  and a second opening  1002   a , which are formed by removing one side of a rectangle, respectively. The first SRR  1001  and the second SRR  1002  have the same shape and are disposed at opposite sides with the dielectric  103  interposed between them while they are misaligned from each other. 
         [0093]    In accordance with an embodiment of the present invention, as illustrated in  FIG. 10 , the dielectric  1003  may have a vertical length a of 10 mm in the Z direction, a horizontal length b of 50 mm in the Y direction, and a length c of 1 mm in the X direction corresponding to the thickness of the dielectric  1003  having the thin plate shape. The first SRR  1001  formed on the dielectric  1003  may have a substantially ‘C’ shape including three lines with the same widths (k=e=g). Furthermore, the first SRR  1001  may have a horizontal length i of 28 mm in the Y direction and a vertical length (e+f+g) of 8 mm in the Z direction. In addition, the lengths k, e, and g corresponding to widths of the sides of the three lines may be 1 mm, respectively. Moreover, in relation to the installation position of the first SRR  1001  on the dielectric  1003 , the distance j from a short side with the vertical length a in the Z direction of the dielectric  1003  to one side with the vertical length (e+f+g) in the Z direction of the first SRR  1001  may be 5 mm, and the distances d and h from a long side with the horizontal length b in the Y direction of the dielectric  1003  to two sides with the horizontal length i in the Y direction of the first SRR  1001  may be 1 mm, respectively. Furthermore, the shape of the second SRR  1002  is the same as that of the first SRR  1001  and the installation position of the second SRR  1002  on the dielectric  1003  is the same as that of the first SRR  1001 . However, the dimensions of each element may be appropriately changed according to the specifications thereof in the embodiment of the present invention. 
         [0094]    Next, the characteristics of the antenna device in accordance with an embodiment of the present invention will be described with reference to  FIGS. 12 and 13 .  FIG. 12  illustrates permittivity characteristics of the antenna device  1000  illustrated in  FIG. 10 , and  FIG. 13  illustrates permeability characteristics of the antenna device  1000  illustrated in  FIG. 10 .  FIGS. 12 and 13  illustrate characteristics of real parts and imaginary parts of permittivity and permeability, respectively. The general characteristics of the SRR regarding such characteristics are the same as those described in the previous embodiment. 
         [0095]    Next, the VSWR frequency characteristics of the antenna device  1000  will be described with reference to  FIG. 14 .  FIG. 14  illustrates the VSWR characteristics obtained by a combination of the first and second SRRs  1001  and  1002  in the antenna device  1000  and an element conductor  1004 . The graph indicated by “Inverted-L+SRR(A)” and “Inverted-L+SRR(B)” in  FIG. 14  illustrate the VSWR characteristics obtained by the combination of the first and second SRRs  1001  and  1002  and an element conductor  1004 . Furthermore, in  FIG. 14 , the VSWR characteristics when only an inverted-L antenna is provided are indicated by “Inverted-L”. 
         [0096]    Referring to the graph of the “Inverted-L+SRR(A)” in  FIG. 14 , it can be understood that the resonant frequency is reduced as compared with the graph of the “Inverted-L”. This is caused by a variation in material characteristics around the resonant frequency of the SRR, and a wavelength shortening effect obtained by multiplying the material constant of the dielectric by the variation in the effective permeability around the resonant frequency of the SRR, which is larger than the wavelength shortening effect due to the material constant. Consequently, the two SRRs are disposed on the front surface and the rear surface of the dielectric, such that the resonant frequency can be reduced as illustrated in the “Inverted-L+SRR(A)”, and the antenna device  1000  can be fabricated in a small size. 
         [0097]    Next, adjustment conditions of the configuration for enabling an operation in a wide band around a desired frequency band in the antenna device will be described below. The VSWR characteristics of the antenna device when the lengths of the conductors of the first SRR  1001  and the second SRR  1002  illustrated in  FIG. 11  are changed to different lengths will be described with reference to  FIGS. 14 and 15 . 
         [0098]      FIG. 15  illustrates an entire configuration example of an antenna device  1500  provided with a first SRR  1501  and a second SRR  1502  which are adjusted to operate in a desired frequency band. The antenna device  1500  illustrated in  FIG. 15  includes the first SRR  1501 , the second SRR  1502 , a dielectric  1503 , an element conductor  1504 , a power supply point  1505 , and a ground conductor  1506 . As illustrated in  FIG. 15 , the first SRR  1501  and the second SRR  1502  have a first opening  1501   a  and a second opening  1502   a , which each are formed by removing one side of a rectangle and have three sides, respectively. The lengths of two sides in the Y direction of the first SRR  1501  are longer than those of two sides in the Y direction of the second SRR  1502 . Furthermore, the antenna device  1500  is substantially identical to that of the antenna device  1000  illustrated in  FIGS. 3A and 3B , except that the lengths in the Y direction of the first SRR  1501  are different from those in the Y direction of the second SRR  1502 . 
         [0099]    Referring to  FIG. 14 , the VSWR characteristics obtained by a combination of the first and second SRRs  1501  and  1502  and the element conductor  1504 , which are illustrated in  FIG. 15 , are indicated by “Inverted-L+SRR opt(C)”. 
         [0100]    The first SRR  1501  illustrated in  FIG. 15  has a length extending in the Y direction, as compared with the first SRR  1001  illustrated in  FIG. 11 , such that the resonant frequency indicated by “Inverted-L+SRR(B)” in the graph of  FIG. 14  is shifted from a high frequency side to a low frequency side. Meanwhile, the second SRR  1502  illustrated in  FIG. 15  has a length in the Y direction, which is shorter than that of the second SRR  1002  illustrated in  FIG. 11 , such that the resonant frequency indicated by “Inverted-L+SRR(A)” in the graph of  FIG. 14  is shifted from the low frequency side to the high frequency side. Furthermore, the length in the Y direction of the element conductor  1504  is shortened, such that the resonant frequency indicated by “Inverted-L+SRR(A)” in the graph of  FIG. 14  is shifted from the low frequency side to the high frequency side. Thus, because the length in the Y direction of the first SRR  1501  is allowed to be longer than the length in the Y direction of the second SRR  1002 , the graph indicated by “Inverted-L+SRR(A)” is shifted to the high frequency side and the graph indicated by “Inverted-L+SRR(B)” is shifted to the low frequency side, resulting in the synthesis with the graph indicated by “Inverted-L+SRR opt(C)”. Consequently, the lengths of the conductors of the first and second SRRs  1501  and  1502  and the length of the element conductor  1504  are adjusted, resulting in the resonance around a desired frequency band. For example, because two-resonance can be achieved around a frequency band of LTE  700  as with the resonant frequency indicated by “Inverted-L+SRR opt(C)” of  FIG. 14 , an operation in a wideband can be performed. 
         [0101]    Furthermore, because the antenna device  1000  in accordance with the embodiment of the present invention can be realized by forming the first SRR  1001  and the second SRR  1002  on the front surface and the rear surface of the dielectric  1003  located between the inverted-L element conductor  1004  and the ground conductor  1006 , the antenna device  1000  can be manufactured in a simple manner. For example, the first SRR  1001  and the second SRR  1002  may be formed by etching the front surface and the rear surface of the dielectric  1003 , or the first SRR  1001  and the second SRR  1002  may be simply bonded to the front surface and the rear surface of the dielectric  1003 . In addition, because the antenna device  1500  in accordance with the embodiment of the present invention can be realized by forming the first SRR  1501  and the second SRR  1502  on the front surface and the rear surface of the dielectric  1503  located between the inverted-L element conductor  1504  and the ground conductor  1506 , the antenna device  1500  can be manufactured in a simple manner. For example, the first SRR  1501  and the second SRR  1502  may be formed by etching the front surface and the rear surface of the dielectric  1503 , or the first SRR  1501  and the second SRR  1502  may be simply bonded to the front surface and the rear surface of the dielectric  1503 . Because it is possible to easily adapt with the situation in which a design is changed to allow the antenna devices  1000  and  1500  to operate in a desired frequency band, the manufacturing cost can be reduced. 
         [0102]    Moreover, the dielectrics  1003  and  1503  in accordance with an embodiment of the present invention may be formed of a flexible dielectric film and such. When the dielectrics  1003  and  1503  are manufactured using a flexible dielectric film substrate, because the dielectrics  1003  and  1503  can be bent, the dielectrics  1003  and  1503  can be easily mounted in a wireless communication apparatus. Furthermore, in addition to the dielectrics  1003  and  1503 , the element conductors  1004  and  1504  or the ground conductors  1006  and  1506  may be formed using a flexible material. 
         [0103]      FIGS. 16A to 16C  illustrate plan views of other shapes of a SRR of the antenna device in accordance with an embodiment of the present invention.  FIG. 16A  illustrates the shape of a SRR  1601  that includes an opening  1601   a  formed by removing a part of a polygonal shape,  FIG. 16B  is a diagram illustrating the shape of a SRR  1602  that includes an opening  1602   a  formed by removing a part of a rectangular shape, and  FIG. 16C  is a diagram illustrating the shape of a SRR  1603  that includes an opening  1603   a  formed by removing a part of a ring shape. The present invention is not limited to the above shapes and includes any shape that can realize the characteristics of the SRR as described above. 
         [0104]      FIG. 17  illustrates a block diagram of the configuration of a wireless communication apparatus provided with an antenna device in accordance with an embodiment of the present invention. The wireless communication apparatus  1700  in accordance with an embodiment of the present invention includes the antenna device  1701  that includes a SRR, a communication unit  1702 , an operation unit  1703 , a display unit  1704 , and a control unit  1705 . 
         [0105]    The communication unit  1702  transmits/receives various control signals and data signals to/from an external communication system or a base station (not shown) through the antenna device  1701  under the control of the control unit  1705 , and simultaneously outputs received information to the control unit  1705 . The control unit  1705  includes a CPU, a ROM, a RAM, an interface, through which signals are input/output to/from the communication unit  1702 , the operation unit  1703  and the display unit  1704 , and such, and controls the entire operation of the wireless communication apparatus  1700  based on control programs stored in the ROM. For example, the control unit  1705  receives signals from the operation unit  1703 , displays a predetermined image on the display unit  1704 , and transmits/received data to/from the communication unit  1702 . Because the wireless communication apparatus  1700  uses the antenna device  1701  that includes the SRR, the wireless communication apparatus  1700  can be easily applied to a next generation communication system, such as LTE  700 , through a design modification thereof, and can be fabricated in a small size. 
         [0106]    In accordance with the embodiments of the present invention as described above, the SRRs are disposed on the front surface and the rear surface of the dielectric located between the inverted-L conductor and the ground conductor, resulting in the achievement of a wavelength shortening effect which is larger than a wavelength shortening effect due to the material constant. Furthermore, because the resonant frequency of the inverted-L antenna can be shifted to a low frequency side, the antenna can be fabricated in a small size. 
         [0107]    In addition, both the lengths of the inverted-L shaped element conductor and the conductor of the SRR are modified, resulting in the achievement of wide band characteristics by which an operation in a desired frequency band is possible. 
         [0108]    The antenna device in accordance with the embodiments of the present invention may be applied to antenna devices used for various mobile information terminals including cell phones, personal computers, and any electronic device capable of wireless communication. 
         [0109]    According to an antenna device and a wireless communication apparatus that includes an antenna device in accordance with an embodiment of the present invention, even if the number of frequency bands used increases, the antenna device can be fabricated in a small size without the increase in the structure thereof and a resonant frequency can be easily changed in a desired frequency band. 
         [0110]    Furthermore, according to an antenna device and a wireless communication apparatus that includes an antenna device in accordance with an embodiment of the present invention, a wavelength shortening effect, which is larger than a wavelength shortening effect due to the material constant, can be achieved and a resonant frequency can be shifted to a low frequency side, such that the antenna device and the wireless communication apparatus that includes an antenna device can be fabricated in a small size. In addition, parameters (the length of a conductive member, the size of an opening, a relative position and the like) regarding the conductive member constituting the antenna device may be adjusted, such that an operation in a desired frequency band is possible. Consequently, it is possible to provide the antenna device and the wireless communication apparatus that includes an antenna device, which can easily achieve wide band characteristics. 
         [0111]    Although the present disclosure has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.