Patent Publication Number: US-2022231404-A1

Title: Communication apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 16/491,573, filed Sep. 6, 2019, which is based on PCT filing PCT/JP2017/045522, filed Dec. 19, 2017, and claims priority to JP 2017-049422, filed Mar. 15, 2017, the entire contents of each are being incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a communication apparatus. 
     BACKGROUND ART 
     A wireless signal with a frequency of around 700 MHz to 3.5 GHz called ultrahigh frequency is mainly used for communication in a mobile communication system based on a communication standard called LTE/LTE-Advanced (A). 
     Further, a technology called multiple-input and multiple-output (MIMO) is employed in communication using an ultrahigh frequency as in the above communication standard so that the communication performance can be further enhanced by use of direct wave and reflected wave for exchanging signals also in the fading environment. A plurality of antennas is used in MIMO, and thus various methods for arranging a plurality of antennas in a more suitable form are discussed for mobile communication terminal apparatuses such as Smartphone. For example. Patent Document 1 discloses an exemplary method for arranging a plurality of antennas for a mobile communication terminal apparatus in a more suitable form assuming the use of MIMO. 
     CITATION LIST 
     Patent Document 
     
         
         Patent Document 1: Japanese Patent Application Laid-Open No. 2013-70365 
       
    
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     Incidentally, there have been discussed various fifth-generation (5G) mobile communication systems subsequent to LTE/LTE-A in recent years. For example, the use of communication using a wireless signal with a frequency of 28 GHz or 39 GHz called millimeter wave (simply called “millimeter wave” below) is discussed in the mobile communication systems. 
     A millimeter wave can further increase the amount of information to be transmitted than an ultrahigh frequency, and tends to be high in straightness and to increase in propagation loss or reflection loss. Thus, it has been known that a direct wave mainly contributes to the communication property and a reflected wave is the least influential in wireless communication using millimeter waves. The introduction of a technology called polarization MIMO is discussed from the above property, which realizes MIMO by use of a plurality of polarized waves (such as horizontal polarized wave and vertical polarized wave) with mutually different polarization directions in the 5G mobile communication systems. The use of polarization MIMO is desired from the background also in a mobile communication apparatus like a mobile communication terminal apparatus. 
     Thus, the present disclosure proposes an exemplary technology capable of realizing polarization MIMO in a more suitable form in a mobile communication apparatus. 
     Solutions to Problems 
     According to the present disclosure, there is provided a communication apparatus including a plurality of antenna parts configured to receive or transmit a wireless signal, a communication control part configured to control transmitting or receiving the wireless signal via at least any of the plurality of antenna parts, and a casing housing the communication control part, in which each of the plurality of antenna parts is held near each of a plurality of partial regions normal directions of which cross each other or the normal directions of which are mutually twisted in outer faces of the casing, and transmit or receive a first wireless signal and a second wireless signal propagating in directions substantially orthogonal to the partial regions and having mutually different polarization directions. 
     Effects of the Invention 
     According to the present disclosure described above, there is provided a technology capable of realizing polarization MIMO in a more suitable form in a portable apparatus. 
     Additionally, the above effect is not necessarily restrictive, and any effect described in the present specification or other effect graspable from the present specification may be obtained together with the above effect or instead of the above effect. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an explanatory diagram for explaining an exemplary schematic configuration of a system according to one embodiment of the present disclosure. 
         FIG. 2  is a block diagram illustrating an exemplary configuration of a terminal apparatus according to the embodiment. 
         FIG. 3  is an explanatory diagram for explaining an exemplary configuration of a communication apparatus according to a comparative example. 
         FIG. 4  is an explanatory diagram for explaining an outline of a patch antenna. 
         FIG. 5  is an explanatory diagram for explaining an exemplary configuration of a communication apparatus according to the embodiment. 
         FIG. 6  is a diagram illustrating exemplary communication property simulation results in a case where a dipole antenna is used as an antenna apparatus. 
         FIG. 7  illustrates exemplary communication property simulation results in a case where a patch antenna is used as an antenna apparatus. 
         FIG. 8  is an explanatory diagram for explaining an exemplary configuration of a communication apparatus according to a first variant. 
         FIG. 9  is an explanatory diagram for explaining an exemplary configuration of an antenna apparatus according to a second variant. 
         FIG. 10  is an explanatory diagram for explaining an outline of a short-circuit patch antenna. 
         FIG. 11  is a diagram illustrating an exemplary configuration of an antenna apparatus according to a third variant. 
         FIG. 12  is a diagram illustrating an exemplary configuration of an antenna apparatus according to a fourth variant. 
         FIG. 13  is a diagram illustrating an exemplary configuration of the antenna apparatus according to the fourth variant. 
         FIG. 14  is an explanatory diagram for explaining an outline of a notch antenna. 
         FIG. 15  is a diagram illustrating an exemplary configuration of an antenna apparatus according to a fifth variant. 
         FIG. 16  is an explanatory diagram for explaining an outline of a monopole antenna. 
         FIG. 17  is a diagram illustrating an exemplary configuration of an antenna apparatus according to a sixth variant. 
         FIG. 18  is an explanatory diagram for explaining an outline of an inverted F-antenna. 
         FIG. 19  is a diagram illustrating an exemplary configuration of an antenna apparatus according to a seventh variant. 
         FIG. 20  is an explanatory diagram for explaining an outline of a loop antenna. 
         FIG. 21  is a diagram illustrating an exemplary configuration of an antenna apparatus according to an eighth variant. 
         FIG. 22  is an explanatory diagram for explaining an outline of a slot antenna. 
         FIG. 23  is a diagram illustrating an exemplary configuration of an antenna apparatus according to a ninth variant. 
         FIG. 24  is an explanatory diagram for explaining an outline of a communication apparatus according to a first example. 
         FIG. 25  is an explanatory diagram for explaining an outline of the communication apparatus according to the first example. 
         FIG. 26  is an explanatory diagram for explaining an outline of a communication apparatus according to a second example. 
         FIG. 27  is an explanatory diagram for explaining an outline of the communication apparatus according to the second example. 
         FIG. 28  is an explanatory diagram for explaining an outline of a communication apparatus according to a third example. 
         FIG. 29  is an explanatory diagram for explaining of an outline of the communication apparatus according to the third example. 
         FIG. 30  is an explanatory diagram for explaining an outline of a communication apparatus according to a fourth example. 
         FIG. 31  is an explanatory diagram for explaining an outline of the communication apparatus according to the fourth example. 
         FIG. 32  is an explanatory diagram for explaining an outline of the communication apparatus according to the fourth example. 
         FIG. 33  is an explanatory diagram for explaining an outline of a communication apparatus according to a fifth example. 
         FIG. 34  is an explanatory diagram for explaining an outline of the communication apparatus according to the fifth example. 
         FIG. 35  is an explanatory diagram for explaining an exemplary configuration of a communication apparatus according to a sixth example. 
         FIG. 36  is an explanatory diagram for explaining an outline of a communication apparatus according to a seventh example. 
         FIG. 37  is an explanatory diagram for explaining an application of the communication apparatus according to the embodiment. 
         FIG. 38  is an explanatory diagram for explaining an application of the communication apparatus according to the embodiment. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Preferred embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings. Additionally, the components having substantially the same functional configurations are denoted with the same reference numerals, respectively, in the present specification and the drawings, and a repeated description thereof will be omitted. 
     Additionally, the description will be made in the following order. 
     1. Schematic configuration 
     1.1. Exemplary system configuration 
     1.2. Exemplary configuration of terminal apparatus 
     2. Examination of communication using millimeter waves 
     3. Technical characteristics 
     3.1. Comparative example 
     3.2. Exemplary configuration 
     3.3. Variants 
     3.4. Examples 
     3.5. Applications 
     4. Conclusion 
     1. SCHEMATIC CONFIGURATION 
     &lt;1.1. Exemplary System Configuration&gt; 
     An exemplary schematic configuration of a system  1  according to one embodiment of the present disclosure will be first described with reference to  FIG. 1 .  FIG. 1  is an explanatory diagram for explaining an exemplary schematic configuration of the system  1  according to one embodiment of the present disclosure. As illustrated in  FIG. 1 , the system  1  includes wireless communication apparatuses  100  and terminal apparatuses  200 . A terminal apparatus  200  is also called user herein. The user can be also called UE. A wireless communication apparatus  100 C is also called UE-Relay. Here, UE may be defined in LTE or LTE-A, or Prose UE to Network Relay discussed in 3GPP, or may more generally mean a communication device. 
     (1) Wireless Communication Apparatuses  100   
     The wireless communication apparatuses  100  are directed to providing a wireless communication service to their controlling apparatuses. For example, a wireless communication apparatus  100 A is a base station of a cellular system (or mobile communication system). The base station  100 A makes wireless communication with apparatuses (such as a terminal apparatus  200 A) positioned inside a cell  10 A of the base station  100 A. For example, the base station  100 A transmits a downlink signal to the terminal apparatus  200 A, and receives an uplink signal from the terminal apparatus  200 A. 
     The base station  100 A is logically connected to other base station via an X2 interface, for example, and can exchange control information and the like therewith. Further, the base station  100 A is logically connected to a so-called core network (not illustrated) via an SI interface, for example, and can exchange control information and the like therewith. Additionally, the communication between the apparatuses can be physically relayed via various apparatuses. 
     Here, the wireless communication apparatus  100 A illustrated in  FIG. 1  is a macrocell base station and the cell  10 A is a macrocell. On the other hand, the wireless communication apparatuses  100 B and  100 C are master devices which operate small cells  108  and  10 C, respectively. By way of example, the master device  100 B is a fixedly-installed small cell base station. The small cell base station  100 B establishes a wireless backhaul link with the macrocell base station  100 A, and an access link with one or more terminal apparatuses (such as the terminal apparatus  200 B) in the small cell  10 B. Additionally, the wireless communication apparatus  100 B may be a relay node defined in 3GPP. The master device  100 C is a dynamic access point (AP). The dynamic AP  100 C is a mobile device which dynamically operates the small cell  10 C. The dynamic AP  100 C establishes a wireless backhaul link with the macrocell base station  100 A, and an access link with one or more terminal apparatuses (such as the terminal apparatus  200 C) in the small cell  10 C. The dynamic AP  100 C may be a terminal apparatus mounting thereon hardware or software operable as a base station or a wireless access point, for example. In this case, the small cell  10 C is a dynamically-formed localized network/virtual cell. 
     The cell  10 A may be operated according to any wireless communication system such as LTE, LTE-Advanced (LTE-A), LTE-ADVANCED PRO, GSM (registered trademark), UMTS, W-CDMA, CDMA200, WiMAX, WiMAX2, or IEEE802.16. 
     Additionally, the concept of a small cell can include various types of cells (such as femtocell, nanocell, picocell, and microcell) smaller than a macrocell arranged to be overlapped or not to be overlapped with the macrocell. In some examples, a small cell is operated by a dedicated base station. In other examples, a small cell is operated when a terminal as master device temporarily operates as a small cell base station. A relay node can be also regarded as one form of the small cell base station. A wireless communication apparatus functioning as a master station of the relay node is also called donor base station. The donor base station may mean DeNB in LTE or may more generally mean a master station of a relay node. 
     (2) Terminal Apparatuses  200   
     The terminal apparatuses  200  can make communication in a cellular system (or mobile communication system). The terminal apparatuses  200  make wireless communication with wireless communication apparatuses (such as the base station  100 A and the mater device  100 B or  100 C) in the cellular system. For example, the terminal apparatus  200 A receives a downlink signal from the base station  100 A, and transmits an uplink signal to the base station  100 A. 
     Further, not only so-called UE but also so-called low cost UE such as MTC terminal, enhanced MTC (eMTC), and NB-IoT terminal may be operated for the terminal apparatuses  200 . 
     (3) Supplement 
     A schematic configuration of the system  1  has been described above, but the present technology is not limited to the example illustrated in  FIG. 1 . For example, a configuration of the system  1  can employ a configuration not including master device, small cell enhancement (SCE), heterogeneous network (HetNet), a MTC network, and the like. Further, as other exemplary configuration of the system  1 , a master device is connected to a small cell, and a cell may be constructed under the small cell. 
     An exemplary schematic configuration of the system  1  according to one embodiment of the present disclosure has been described above with reference to  FIG. 1 . 
     &lt;1.2. Exemplary Configuration of Terminal Apparatus&gt; 
     An exemplary configuration of the terminal apparatus  200  according to an embodiment of the present disclosure will be described below with reference to  FIG. 2 .  FIG. 2  is a block diagram illustrating an exemplary configuration of the terminal apparatus  200  according to an embodiment of the present disclosure. As illustrated in  FIG. 2 , the terminal apparatus  200  includes an antenna part  2001 , a wireless communication part  2003 , a storage part  2007 , and a communication control part  2005 . 
     (1) Antenna Pan  2001   
     The antenna part  2001  radiates a signal output from the wireless communication part  2003  as a radiowave to the space. Further, the antenna part  2001  converts the radiowave in the space into a signal, and outputs the signal to the wireless communication part  220 . 
     (2) Wireless Communication Part  2003   
     The wireless communication part  2003  exchanges signals. For example, the wireless communication part  2003  receives a downlink signal from a base station, and transmits an uplink signal to the base station. 
     (3) Storage Part  2007   
     The storage part  2007  temporarily or permanently stores programs and various items of data for operating the terminal apparatus  200 . 
     (4) Communication Control Part  2005   
     The communication control part  2005  controls the operations of the wireless communication part  2003  thereby to control communication with other apparatus (such as the base station  100 ). As a specific example, the communication control part  2005  may modulate data to be transmitted on the basis of a predetermined modulation system thereby to generate a transmission signal, and may cause the wireless communication part  2003  to transmit the transmission signal to the base station  100 . Further, as other example, the communication control part  2005  may acquire a signal reception result (or reception signal) from the base station  100  by the wireless communication part  2003 , and may perform a predetermined demodulation processing on the reception signal thereby to demodulate the data transmitted from the base station  100 . 
     An exemplary configuration of the terminal apparatus  200  according to the embodiment of the present disclosure has been described above with reference to  FIG. 2 . 
     &lt;&lt;2.2. Examination of Communication Using Millimeter Waves&gt;&gt; 
     A wireless signal with a frequency of around 700 MHz to 3.5 GHz called ultrahigh frequency is used for communication in the communication system based on a standard such as LTE/LTE-A. To the contrary, the use of communication using a wireless signal with a frequency of 28 GHz or 39 GHz called millimeter wave (simply called “millimeter wave” below) is examined in the fifth-generation (5G) mobile communication system subsequent to LTE/LTE-A. Thus, an outline of communication using millimeter waves will be described, and then technical problems of the communication apparatus according to one embodiment of the present disclosure will be described. 
     A technology called multiple-input and multiple-output (MIMO) is employed in communication using an ultrahigh frequency such as LTE/LTE-A so that the communication performance can be further enhanced by use of direct wave and reflected wave for exchanging signals also in the fading environment. 
     To the contrary, a millimeter wave can further increase the amount of information to be transmitted than an ultrahigh frequency, and tends to be high in straightness and to increase in propagation loss or reflection loss. Thus, a reflected wave is the least influential and a direct wave mainly contributes to the communication property in an environment (so-called line of site (LOS)) in which an obstacle is not present on a path directly connecting the antennas via which wireless signals are exchanged. Due to the property, a communication terminal such as Smartphone receives a wireless signal (or millimeter wave) directly transmitted from a base station (or receives a direct wave) thereby to further enhance the communication performance in communication using millimeter waves. 
     Further, as described above, a direct wave mainly contributes to the communication property and a reflected wave is the least influential in communication using millimeter waves. Due to the property, the introduction of a technology called polarization MIMO is examined, which realizes MIMO by use of a plurality of polarized waves (such as horizontal polarized wave and vertical polarized wave) with mutually different polarization directions in wireless signals transmitted as direct waves in communication using millimeter waves between a communication terminal and a base station. Additionally, a “polarization direction” corresponds to a direction in which a wireless signal (or polarized wave) oscillates in the present disclosure. That is, a so-called “polarization plane” is defined by a direction in which a wireless signal propagates and a polarization direction of the wireless signal. Further, a polarized wave the polarization plane of which is vertical to the ground corresponds to “vertical polarized wave” and a polarized wave the polarization plane of which is horizontal to the ground corresponds to “horizontal polarized wave”. 
     However, a portable terminal apparatus such as mobile communication terminal including Smartphone changes in its position or orientation over time along with movement of a user holding the terminal apparatus, a change in form of holding the terminal apparatus, or the like. Under such a situation, a relative positional relationship between a terminal apparatus and a base station changes over time, and thus a direction in which a direct wave arrives at the terminal apparatus from a base station also changes. This is similarly applicable when a communication apparatus itself is mobile. 
     Further, as described above, a millimeter wave is higher in reflection loss than an ultrahigh frequency, and is more easily reflected by a human body. Thus, for example, if a communication path directly connecting an antenna device provided in a terminal apparatus and a base station is blocked by a site such as hand holding the casing of the terminal apparatus, a millimeter wave propagating in the communication path is blocked by the site such as hand. That is, a position in the terminal apparatus capable of exchanging millimeter waves via communication with a base station (or a position not blocked by a hand or the like) also changes depending on a position of the terminal apparatus held by a site such as hand. 
     In terms of the above situation, the present disclosure proposes a communication apparatus capable of realizing polarization MIMO using a direct wave in a more suitable form in communication with other apparatus via a wireless communication path also in a situation in which a position or orientation changes over time. 
     3. TECHNICAL CHARACTERISTICS 
     Technical characteristics of a communication apparatus according to one embodiment of the present disclosure will be described below. 
     3.1. COMPARATIVE EXAMPLE 
     An exemplary configuration of a communication apparatus according to a comparative example will be first described with reference to  FIG. 3  in order to easily understand the characteristics of a communication apparatus (such as the terminal apparatus  200 ) according to the present embodiment.  FIG. 3  is an explanatory diagram for explaining an exemplary configuration of the communication apparatus according to the comparative example. Additionally, the communication apparatus according to the comparative example may be denoted as “communication apparatus  290 ” in the following description in order to discriminate from the communication apparatus according to the present embodiment. 
     The communication apparatus  290  according to the comparative example includes a plate-shaped casing  209  which has a top side and a backside and forms a substantially-rectangular shape. Additionally, a side on which a display part such as display is provided is called top side in the present description. That is, a reference numeral  201  in  FIG. 3  indicates the backside in the outer faces of the casing  20 ). Further, reference numerals  203  and  205  correspond to end faces positioned around the backside  201  in the outer faces of the casing  209 , and more specifically indicate end faces extending in the longitudinal direction of the backside  201 . Further, reference numerals  202  and  204  correspond to end faces positioned around the backside  201  in the outer faces of the casing  209 , and more specifically indicate end faces extending in the short direction of the backside  201 . Additionally, though not illustrated in  FIG. 3 , a top side positioned opposite to the backside  201  is also called “top side  206 ” for convenience. 
     Further, reference numerals  2900   a  to  2900   f  in  FIG. 3  indicate an antenna apparatus for exchanging wireless signals (such as millimeter waves) with a base station. Additionally, in a case where the antenna apparatuses  2900   a  to  2900   f  are not particularly discriminated in the following description, they may be simply called “antenna apparatuses  2900 ”. Further, a reference numeral  2901  indicates an individual antenna device (such as antenna element). Additionally, in the example illustrated in  FIG. 3 , the antenna device  2901  is configured as a so-called dipole antenna. 
     As illustrated in  FIG. 3 , the communication apparatus  290  is configured such that the antenna apparatuses  2900  are held (installed) inside the casing  209  to be positioned near each of the end faces  202  to  205  provided along the outer periphery of the backside  201  (in other words, the top side  206 ). 
     For example, the antenna apparatus  2900   a  is provided inside the casing  209  to be positioned near both the end faces  202  and  203 . Further, the antenna apparatus  2900   a  has a plurality of antenna devices  2901  configured as dipole antennas. Specifically, some antenna devices  2901  among the plurality of antenna devices  2901  of the antenna apparatus  2900   a  are provided to extend in the longitudinal direction of the end face  203 , and the other antenna devices  2901  are provided to extend in the longitudinal direction of the end face  205 . 
     Further, the antenna apparatuses  2900   c ,  2900   d , and  2900   f  are held on the basis of the similar spirit to the antenna apparatus  2900   a . That is, the antenna apparatus  2900   c  is provided inside the casing  209  to be positioned near both the end faces  203  and  204 . Further, the antenna apparatus  2900   d  is provided inside the casing  209  to be positioned near both the end faces  204  and  205 . Further, the antenna apparatus  2900   f  is provided inside the casing  209  to be positioned near both the end faces  205  and  202 . 
     Further, the antenna apparatus  2900   b  is provided inside the casing  209  to be positioned near the end face  203 . Further, the antenna apparatus  2900   b  has one or more antenna devices  2901  configured as dipole antennas. Specifically, the plurality of antenna devices  2901  of the antenna apparatus  2900   b  is provided to extend in the longitudinal direction of the end face  203 . 
     Further, the antenna apparatus  2900   e  is provided on the basis of the similar spirit to the antenna apparatus  2900   b . That is, the antenna apparatus  2900   e  is provided inside the casing  209  to be positioned near the end face  205 . 
     A polarization direction of a polarized wave transmittable or receivable by an antenna apparatus will be described herein. Generally, an antenna apparatus is different in polarization direction of a transmittable or receivable polarized wave depending on the orientation of a current flowing in an element such as a radiation device or waveguide device of the antenna apparatus. For example, in the case of a dipole antenna, a polarized wave the polarization direction of which substantially matches with a direction in which a rod-shaped element extends can be transmitted or received (that is, preferable communication property is indicated). That is, only one polarized wave can be transmitted or received by the dipole antenna. 
     Thus, the polarization directions of polarized waves capable of being transmitted or received by each of the antenna apparatuses  2900   a  to  2900   f  are determined depending on directions in which the elements of the antenna devices  2901  of the antenna apparatuses  2900  extend. For example, the antenna apparatus  2900   a  includes an antenna device  2901  in which the element extends in the longitudinal direction of the end face  202 , and an antenna device  2901  extending in the longitudinal direction of the end face  203 . Thus, the antenna apparatus  2900   a  can transmit or receive two polarized waves including a polarized wave the polarization direction of which substantially matches with the longitudinal direction (or the direction R H  in the figure) of the end face  202 , and a polarized wave the polarization direction of which substantially matches with the longitudinal direction (or the direction R V  in the figure) of the end face  203 . Further, the antenna apparatus  2900   b  includes an antenna device  2901  extending in the longitudinal direction of the end face  203 . Thus, the antenna apparatus  2900   b  can transmit or receive a polarized wave the polarization direction of which substantially matches with the longitudinal direction (or the direction R V ) of the end face  203 . Additionally, in the following description, a polarized wave the polarization direction of which substantially matches with the direction R H  in the figure will be simply called “polarized wave R H ” and a polarized wave the polarization direction of which substantially matches with the direction R V  in the figure will be simply called “polarized wave R V ”. Further, one of the polarized waves R H  and R V  with mutually different polarization directions may correspond to horizontal polarized wave, and the other may correspond to vertical polarized wave. 
     With the above configuration, the antenna apparatuses  2900   a  to  2900   f  are arranged at the respective positions, and thus the communication apparatus  290  can transmit or receive wireless signals propagating in each direction with reference to the communication apparatus  290  by any antenna apparatus  2900 . Further, two polarized waves R H  and R V  can be transmitted or received in wireless signals propagating in a direction substantially matching with the normal direction of the backside  201 . This is similarly applicable to the top side  206 . Further, each of the antenna apparatuses  2900   a  to  2900   f  is such that an antenna pattern is arranged on a substrate and an integrated circuit (IC) is arranged near the antenna pattern, thereby reducing the substrate wiring and achieving a high degree of freedom of design. 
     However, in terms of each of the end faces  202  to  205 , transmittable or receivable polarized waves in wireless signals propagating in a direction substantially matching with the normal direction of each end face are limited to only the polarized waves the polarization directions of which substantially match with the longitudinal direction of each end face in the communication apparatus  290 . As a specific example, only the polarized wave R H  can be transmitted or received in wireless signals propagating in a direction substantially matching with the normal direction of the end face  202 , and a polarized wave the polarization direction of which substantially matches with the short direction (or the thickness direction of the casing  209 ) of the end face  202  is difficult to transmit or receive. Further, only the polarized wave R V  can be transmitted or received in wireless signals propagating in a direction substantially matching with the normal direction of the end face  205 , and a polarized wave the polarization direction of which substantially matches with the short direction (or the thickness direction of the casing  209 ) of the end face  205  is difficult to transmit or receive. 
     That is, in a case where polarization MIMO is introduced into communication using millimeter waves, the communication apparatus  290  according to the comparative example deteriorates in the communication property (such as antenna gain) in transmitting or receiving wireless signals propagating in a direction substantially matching with the normal direction of each of the end faces  202  to  205 . 
     An exemplary configuration of the communication apparatus according to the comparative example has been described above with reference to  FIG. 3 . 
     3.2. EXEMPLARY CONFIGURATION 
     An exemplary configuration of a communication apparatus according to the present embodiment will be subsequently described assuming that a patch antenna (plane antenna) is applied. 
     An outline of a patch antenna will be first described with reference to  FIG. 4 .  FIG. 4  is an explanatory diagram for explaining an outline of a patch antenna. As described above, a dipole antenna has a rod-shaped element, and thus a current flows only in one direction, and only one polarized wave can be transmitted or received. To the contrary, a patch antenna is provided with a plurality of power supply points, and thus can flow a current in a plurality of directions. For example, a patch antenna  2111  illustrated in  FIG. 4  is provided with a plurality of power supply points  2115  and  2117  for a planar element  2113 , and is configured to be able to transmit or receive each of the polarized waves R H  and R V  with mutually different (mutually orthogonal) polarization directions. 
     An exemplary configuration of a communication apparatus according to the present embodiment will be described below with reference to  FIG. 5 .  FIG. 5  is an explanatory diagram for explaining an exemplary configuration of a communication apparatus according to the present embodiment. Additionally, the communication apparatus according to the present embodiment illustrated in  FIG. 5  may be denoted as “communication apparatus  211 ” in the following description in order to discriminate from the communication apparatus according to the comparative example or the communication apparatuses according to the respective variants described below. Additionally, the description will be made assuming that the communication apparatus  211  has the similar casing  209  to that of the communication apparatus  290  according to the comparative example. That is, the backside  201  and the end faces  202  to  205  illustrated in  FIG. 5  indicate the backside  201  and the end faces  202  to  205  of the casing  209 , respectively, similarly to the example illustrated in  FIG. 3 . This is similarly applicable to the top side  206  (not illustrated). 
     Reference numerals  2111   a  to  2111   f  each indicate an antenna apparatus for exchanging wireless signals (such as millimeter waves) with a base station. In the example illustrated in  FIG. 5 , each of the antenna apparatuses  2111   a  to  2111   f  is configured as the patch antenna  2111  described with reference to  FIG. 4 . Additionally, each of the antenna apparatuses  2111   a  to  2111   f  corresponds to exemplary “antenna parts”. 
     As illustrated in  FIG. 5 , in the communication apparatus  211 , the patch antennas  2111  are held (installed) inside the casing  209  to be positioned near at least some of the backside  201  and each of the end faces  202  to  205 . At this time, the patch antenna  2111  held to be positioned near a face is held such that the normal direction of the planar element  2113  substantially matches with the normal direction of the face. 
     For example, the antenna apparatuses  2111   a  and  2111   b  (the patch antennas  2111 ) are held inside the casing  209  such that they are positioned near the backside  201  and the normal directions thereof substantially match with the normal direction of the backside  201 . With the configuration, the antenna apparatuses  2111   a  and  2111   b  can transmit or receive the two polarized waves R H  and R V  with mutually different (mutually orthogonal) polarization directions in wireless signals propagating in a direction substantially matching with the normal direction of the backside  201 . Additionally, the respective polarization directions of the polarized waves R H  and R V  are orthogonal to the direction in which the wireless signals propagate. Further, though not illustrated in  FIG. 5 , the patch antennas  2111  may be installed also on the top side  206  similarly to the backside  201 . 
     Further, the antenna apparatus  2111   c  (patch antenna  2111 ) is held inside the casing  209  such that it is positioned near the end face  202  and the normal direction thereof substantially matches with the normal direction of the end face  202 . That is, the antenna apparatus  2111   c  can transmit or receive the two polarized waves R H  and R V  with mutually different (mutually orthogonal) polarization directions in wireless signals propagating in a direction substantially matching with the normal direction of the end face  202 . Further, each of the antenna apparatuses  2111   d  to  2111   f  is held on the basis of the similar spirit to the antenna apparatus c. That is, the antenna apparatus  2111   d  is held inside the casing  209  such that it is positioned near the end face  203  and its normal direction substantially matches with the normal direction of the end face  203 . Further, the antenna apparatus  2111   e  is held inside the casing  209  such that it is positioned near the end face  204  and its normal direction substantially matches with the normal direction of the end face  204 . Further, the antenna apparatus  2111   f  is held inside the casing  209  such that it is positioned near the end face  205  and its normal direction substantially matches with the normal direction of the end face  205 . 
     In this way, the communication apparatus  211  according to the present embodiment is such that an antenna apparatus is held near each partial region with a mutually different direction or each of a plurality of partial regions with mutually different normal directions on the outer faces of the casing  209 . Particularly the communication apparatus  211  according to the present embodiment is such that an antenna apparatus (such as patch antenna  2111 ) is held near each of a plurality of partial regions the normal directions of which cross each other or the normal directions of which are mutually twisted in the outer faces of the casing  209  like the backside  201  (or the top side  206 ) and each of the end faces  202  to  205 . Further, the antenna apparatus is configured to be able to transmit or receive a plurality of polarized waves (such as two polarized waves R H  and R V ) propagating in directions substantially matching with the normal directions of the partial regions positioned nearby (or in directions substantially orthogonal to the partial regions) and having mutually different polarization directions. Additionally, one polarized wave of the plurality of polarized waves (such as polarized waves R H  and R V ) transmitted or received by the antenna apparatus corresponds to “first wireless signal” and the other polarized wave corresponds to “second wireless signal”. 
     With the above configuration, the communication apparatus  211  according to the present embodiment can transmit or receive the two polarized waves R H  and R V  with mutually different polarization directions in wireless signals propagating in a direction substantially matching with the normal directions of any face of six faces of the backside  201 , the top side  206 , and the end faces  202  to  205  of the casing  209 . 
     Exemplary communication properties will be described herein with reference to  FIG. 6  and  FIG. 7  assuming that a dipole antenna and a patch antenna are used as antenna apparatuses. For example,  FIG. 6  is a diagram illustrating exemplary communication property simulation results in a case where a dipole antenna is used as an antenna apparatus. Further,  FIG. 7  illustrates exemplary communication property simulation results in a case where a patch antenna is used as an antenna apparatus. The horizontal axis in  FIG. 6  and  FIG. 7  indicates antenna gain. Further, the vertical axis indicates coverage, or a ratio of a region with antenna gain of a value indicated on the horizontal axis or more relative to the 360-degree spherical plane with reference to each apparatus. Additionally,  FIG. 6  and  FIG. 7  illustrate simulation results for V polarization with a polarization direction of Phi direction, H polarization with a polarization direction of Theta direction, and total polarization. Further,  FIG. 6  and  FIG. 7  indicate exemplary simulation results in a case where the target antenna gain is assumed at 1.8 dB. 
     As illustrated in  FIG. 6 , in a case where a dipole antenna is used, 70% of the coverage is totally secured at an antenna gain of 1.8 dB. However, the coverage per polarization is as low as 58% for V polarization (Phi direction), and is so low at 0.004% for H polarization (Theta direction). 
     To the contrary, in a case where a patch antenna is used, 100% of the coverage can be totally secured at an antenna gain of 1.8 dB as illustrated in  FIG. 7 . Further, the coverage per polarization is also secured at 96% for both V polarization (Phi direction) and H polarization (Theta direction). It can be seen from the above fact that a preferable communication property is demonstrated for both V polarization (Phi direction) and H polarization (Theta direction) in almost all the directions in a case where a patch antenna is used. 
     An exemplary configuration of the communication apparatus according to the present embodiment has been described above with reference to  FIG. 4  to  FIG. 7  in a case where a patch antenna (planar antenna) is applied. Additionally, the simulation results described with reference to  FIG. 6  and  FIG. 7  are merely exemplary, and the target antenna gain may be different per antenna to be used. 
     3.3. VARIANTS 
     Variants of the communication apparatus according to the present embodiment will be subsequently described. 
     (First Variant: Exemplary Configuration in a Case where Beam Forming is Performed) 
     An exemplary configuration of a communication apparatus according to a first variant will be first described in a case where a technology called beam forming is used. 
     An outline of beam forming will be first described. Beam forming is a technology for enhancing directivity of an antenna apparatus (or narrowing a beam) thereby to enable an antenna gain to be enhanced when transmitting or receiving a wireless signal propagating in a direction by the directivity. Specifically, in beam forming, the phases or power of wireless signals transmitted or received by each of a plurality of antennas (such as antenna elements) are controlled thereby to optimize a radiowave sensitivity at a specific point. The control can further enhance the antenna gain in a case where a wireless signal is transmitted or received in a direction with the directivity of an antenna apparatus. 
     A configuration of a communication apparatus according to the first variant will be described below with reference to  FIG. 8 .  FIG. 8  is an explanatory diagram for explaining an exemplary configuration of the communication apparatus according to the first variant. Additionally, the communication apparatus according to the first variant may be denoted as “communication apparatus  213 ” in the following description in order to discriminate from the communication apparatus according to the above embodiment or the communication apparatuses according to the other variants. Additionally, the present description will be made assuming that the communication apparatus  213  has the similar casing  209  to the communication apparatus  211  according to the above embodiment. That is, it is assumed that the backside  201  and each of the end faces  202  to  205  illustrated in  FIG. 8  indicate the backside  201  and each of the end faces  202  to  205  of the casing  209 , similarly as in the example illustrated in  FIG. 5 . This is similarly applicable to the top side  206  (not illustrated). 
     Reference numerals  2130   a  to  2130   f  in  FIG. 8  each indicate an antenna apparatus for exchanging wireless signals (such as millimeter waves) with a base station. Additionally, in a case where the antenna apparatuses  2130   a  to  2130   f  are not particularly discriminated from each other, they may be simply denoted as “antenna apparatuses  2130 ” in the following description. 
     As illustrated in  FIG. 8 , in the communication apparatus  213  according to the first variant, the antenna apparatuses  2130  are held (installed) inside the casing  209  to be positioned near at least some of the backside  201  and each of the end faces  202  to  205  similarly to the communication apparatus  211  described with reference to  FIG. 5 . 
     Further, an antenna apparatus  2130  includes a plurality of antenna devices  2131 . For example, the antenna apparatus  2131   a  is held to be positioned near the end close to the end face  204  on the backside  201 , where a plurality of antenna devices  2131  is provided to be arranged in a direction in which the end extends (or in the longitudinal direction of the end face  204 ). Further, the antenna apparatus  2131   d  is held to be positioned near part of the end face  205 , where a plurality of antenna devices  2131  is provided to be arranged in the longitudinal diction of the end face  205 . 
     Further, each antenna device  2131  has the similar configuration to the patch antenna  2111  described with reference to  FIG. 4  and  FIG. 5 . That is, in an antenna apparatus  2130  held to be positioned near a face, each antenna device  2131  is held such that the normal direction of the planar element (such as the element  2113  illustrated in  FIG. 3 ) substantially matches with the normal direction of the face. As a more specific example, in terms of the antenna apparatus  2130   a , the antenna devices  2131  provided in the antenna apparatus  2130   a  are held such that the normal directions of the planar elements substantially match with the normal direction of the backside  201 . This is similarly applicable to the other antenna apparatuses  2130   b  to  2130   f.    
     With the above configuration, each antenna apparatus  2130  controls the phases or power of wireless signals transmitted or received by each of the plurality of antenna devices  2131 , thereby to control the directivity of the wireless signals (or to perform beam forming). 
     An exemplary configuration of the communication apparatus according to the first variant has been described above with reference to  FIG. 8  in a case where a technology called beam forming is used. Additionally, the above configuration of the antenna apparatuses  2130  is merely exemplary, and does not necessarily limit the configuration of the antenna apparatuses  2130 . For example, if each of the plurality of antenna devices  2131  can transmit or receive wireless signals propagating in a direction substantially matching with the normal direction of a face which the antenna apparatus  2130  is held near, the position where each of the plurality of antenna devices  2131  is arranged is not particularly limited. That is, the plurality of antenna devices  2131  may not be arranged only in one direction, not as illustrated in  FIG. 8 . For example, the plurality of antenna devices  2131  may be arranged in a matrix shape. This is similarly applicable also when a plurality of antenna devices is arranged in the other variants described below. 
     (Second Variant: Exemplary Configuration of Antenna Apparatus) 
     An exemplary configuration of an antenna apparatus applied to the communication apparatus according to the preset embodiment will be subsequently described according to a second variant. 
     In the communication apparatus  213  described with reference to  FIG. 8 , the antenna apparatuses  2130  provided on each face can be provided near each other in terms of the backside  201  and each of the end faces  204  and  205  which are mutually continuous on the outer faces of the casing  209 . Specifically, the antenna apparatus  2130   a  and the antenna apparatus  2130   f  are adjusted in their respective holding positions to be positioned near the boundary between the backside  201  and the end face  204 , thereby being provided near each other. Similarly, the antenna apparatus  2130   b  and the antenna apparatus  2130   d  are adjusted in their respective holding positions to be positioned near the boundary between the backside  201  and the end face  205 , thereby being provided near each other. 
     In terms of such a situation, the second variant will be described in a case where the antenna apparatuses capable of being installed near each other among the antenna apparatuses  2130  described according to the first variant are integrally configured. For example,  FIG. 9  is an explanatory diagram for explaining an exemplary configuration of the antenna apparatuses according to the second variant, and is a schematic perspective view of the antenna apparatuses. 
     As illustrated in  FIG. 9 , an antenna apparatus  2140  according to the second variant is configured such that two mutually different antenna apparatuses  2130  are coupled by a coupling part  2141 . Additionally, the example illustrated in  FIG. 9  illustrates that the antenna apparatuses  2130   a  and  2130   f  described with reference to  FIG. 8  are coupled to be integrally configured by way of example in order to easily understand the characteristics of the antenna apparatus  2140 . 
     Specifically, the antenna apparatus  2130   a  and the antenna apparatus  21301   f  are arranged such that the respective ends extending in the directions in which the plurality of antenna devices  2131  is arranged are positioned near each other. At this time, the antenna devices  2131  of the antenna apparatus  2130   a  and the antenna devices  2131  of the antenna apparatus  2130   f  are arranged such that the normal directions of the planar elements cross each other (or are orthogonal to each other) or the normal directions are mutually twisted. Further, the coupling part  2141  is provided to cross the ends positioned near each other between the antenna apparatus  2130   a  and the antenna apparatus  2130   f , and the antenna apparatus  2130   a  and the antenna apparatus  2130   f  are coupled by the coupling part  2141 . 
     It is better that the thus-configured antenna apparatus  2140  is held along a plurality of mutually-coupled faces (outer faces) on the outer faces of the casing  209  like the backside  201  and the end face  204  illustrated in  FIG. 8 , for example. With the configuration, each of a plurality of polarized waves with mutually different polarization directions, which arrives at each of the plurality of mutually-coupled faces in the directions substantially orthogonal to the faces, can be transmitted or received in a more suitable form. 
     An exemplary configuration of the antenna apparatus applied to the communication apparatus according to the present embodiment has been described above according to the second variant with reference to  FIG. 9 . 
     (Third Variant: Exemplary Configuration in a Case where Short-Circuit Patch Antenna is Applied) 
     An exemplary configuration of an antenna apparatus according to a third variant will be subsequently described in a case where a short-circuit patch antenna is applied as an antenna device. 
     An outline of a short-circuit patch antenna will be first described with reference to  FIG. 10 .  FIG. 10  is an explanatory diagram for explaining an outline of a short-circuit patch antenna. In  FIG. 10 , the two diagrams on the left side illustrate an exemplary schematic configuration of a patch antenna, and the two diagrams on the right side illustrate an exemplary schematic configuration of a short-circuit patch antenna. 
     Specifically, the lower left diagram illustrates an exemplary schematic configuration of a patch antenna  2111 ′ viewed in the normal direction of the planar element  2113 . Additionally, the example illustrated in  FIG. 10  illustrates that one power supply point is provided for the patch antenna  2111 ′ illustrated in  FIG. 10  (or only a power supply point  2115  is provided) in order to easily understand the characteristics of the short-circuit patch antenna. Further, the upper left diagram illustrates an exemplary schematic configuration of the lower left patch antenna  2111 ′ viewed from an end, where the vertical direction corresponds to the thickness direction of the lower left patch antenna  2111 ′(or the normal direction of the element  2113 ). That is, part of the planar element  2113  downward extends, and the power supply point is provided between the extending part and the ground (GND). 
     Further, the lower right diagram illustrates an exemplary schematic configuration of a short-circuit patch antenna  2151  viewed in the normal direction of a planar element  2153 . As illustrated, the short-circuit patch antenna  2151  is provided with a power supply point  2155  at part of the element  2153 . Further, the short-circuit patch antenna  2151  is provide with a short-circuit part  2157  short-circuited (or electrically connected to the GND) at a different position from the position where the power supply point  2155  is provided on the element  2153 . For example, the upper right diagram illustrates an exemplary schematic configuration of the lower right short-circuit patch antenna  2151  viewed from an end, where the vertical direction corresponds to the thickness direction of the lower right short-circuit patch antenna  2151  (or the normal direction of the element  2153 ). 
     As illustrated in  FIG. 10 , the short-circuit patch antenna  2151  has one power supply point, and thus a plurality of polarized waves is difficult to transmit or receive unlike the patch antenna  2111  described with reference to  FIG. 4 . However, the short-circuit patch antenna  2151  can reduce the rate of the region occupied by the planar element  2153  as compared with the patch antenna  2111  as illustrated in  FIG. 10 , thereby achieving further downsizing. 
     According to the above description, an exemplary configuration of an antenna apparatus in which the short-circuit patch antenna  2151  described with reference to  FIG. 10  is applied as an antenna device will be described with reference to  FIG. 11 .  FIG. 11  is a diagram illustrating an exemplary configuration of an antenna apparatus according to the third variant. Additionally,  FIG. 11  illustrates an exemplary schematic configuration of an antenna apparatus  2150  viewed in the normal direction of a face in a case where the antenna apparatus  2150  according to the third variant is positioned near the face (such as part of the outer faces of the casing  209 ). That is, the antenna apparatus  2150  illustrated in  FIG. 11  mainly transmits or receives wireless signals propagating in a direction substantially matching with the depth direction of  FIG. 11 . 
     As described above, the short-circuit patch antenna  2151  can transmit or receive only one polarized wave. Thus, the antenna apparatus  2150  illustrated in  FIG. 11  is provided with a plurality of short-circuit patch antennas  2151  (or short-circuit patch antennas  2151   a  and  2151   b ) to be able to transmit or receive polarized waves with mutually different polarization directions. 
     Specifically, the short-circuit patch antenna  2151   a  is arranged such that the direction of a current flowing in the planar element substantially matches with the direction in which the plurality of short-circuit patch antennas  2151  is arranged (or the horizontal direction of  FIG. 11 ). That is, the short-circuit patch antenna  2151   a  can transmit or receive the polarized wave RR the polarization direction of which substantially matches with the direction in which the plurality of short-circuit patch antennas  2151  is arranged in wireless signals transmitted or received by the antenna apparatus  2150 . 
     To the contrary, the short-circuit patch antenna  2151   b  is arranged such that the direction of a current flowing in the planar element substantially matches with a direction orthogonal to the direction in which the plurality of short-circuit patch antennas  2151  is arranged (or the vertical direction of  FIG. 11 ). That is, the short-circuit patch antenna  2151   b  can transmit or receive the polarized wave R V  the polarization direction of which substantially matches with the direction orthogonal to the direction in which the plurality of short-circuit patch antennas  2151  is arranged in wireless signals transmitted or received by the antenna apparatus  2150 . 
     With the above configuration, the antenna apparatus  2150  according to the third variant can transmit or receive a plurality of polarized waves with mutually different polarization directions also in a case where the short-circuit patch antennas  2151  capable of transmitting or receiving only one polarized wave are applied. 
     Additionally, if one or more short-circuit patch antennas  2151   a  and  2151   b  are each provided, the numbers of short-circuit patch antennas  2151   a  and  2151   b  are not particularly limited. However, it is desirable that a plurality of short-circuit patch antennas  2151   a  and  2151   b  is each provided as in the communication apparatus  213  according to the first variant in a case where beam forming is used. 
     An exemplary configuration of the antenna apparatus has been described above according to the third variant with reference to  FIG. 10  and  FIG. 11  in a case where short-circuit patch antennas are applied as antenna devices. 
     (Fourth Variant: Exemplary Configuration in a Case where Dipole Antenna is Applied) 
     An exemplary configuration of an antenna apparatus according to a fourth variant will be subsequently described in a case where a dipole antenna is applied as an antenna device. 
     As described above, a current flows in a rod-shaped element in one direction, and thus a dipole antenna itself can transmit or receive only one polarized wave. On the other hand, on the basis of the similar spirit to the third variant, a plurality of antenna devices is arranged in consideration of the direction of a polarized wave transmittable or receivable by each antenna device, thereby transmitting or receiving polarized waves with mutually different polarization directions similarly to the patch antenna. 
     For example,  FIG. 12  and  FIG. 13  are diagrams illustrating exemplary configurations of an antenna apparatus according to the fourth variant. Additionally,  FIG. 12  illustrates an exemplary schematic configuration of an antenna apparatus  2160  viewed in the normal direction of a face in a case where the antenna apparatus  2160  according to the fourth variant is held to be positioned near the face (such as part of the outer faces of the casing  209 ). That is, the antenna apparatus  2160  illustrated in  FIG. 12  mainly transmits or receives wireless signals propagating in a direction substantially matching with the depth direction of  FIG. 12 . 
     As illustrated in  FIG. 12 , the antenna apparatus  2160  is provided with a plurality of dipole antennas  2161  (or dipole antennas  2161   a  ad  2161   b ) to be able to transmit or receive polarized waves with mutually different polarization directions. 
     The dipole antenna  2161   a  is arranged such that the direction of a current flowing in the rod-shaped element substantially matches with a direction in which the plurality of dipole antennas  2161  are arranged (or the horizontal direction of  FIG. 12 ). That is, the dipole antenna  2161   a  can transmit or receive the polarized wave R H  the polarization direction of which substantially matches with the direction in which the plurality of dipole antennas  2161  is arranged in wireless signals transmitted or received by the antenna apparatus  2160 . 
     To the contrary, the dipole antenna  2161   b  is arranged such that the direction of a current flowing in the rod-shaped element substantially matches with a direction orthogonal to the direction in which the plurality of dipole antennas  2161  is arranged (or the vertical direction of  FIG. 12 ). That is, the dipole antenna  2161   a  can transmit or receive the polarized wave R V  the polarization direction of which substantially matches with the direction orthogonal to the direction in which the plurality of dipole antennas  2161  is arranged in wireless signals transmitted or received by the antenna apparatus  2160 . 
     For example,  FIG. 13  is a diagram illustrating an exemplary schematic internal structure of a part where the antenna apparatus  2160  is arranged in the casing  209  of the communication apparatus (such as the terminal apparatus  200 ) according to the present embodiment, and schematically illustrates an exemplary method for arranging the respective antenna devices (or the dipole antennas  2161 ) included in the antenna apparatus  2160 . Additionally,  FIG. 13  illustrates that the antenna apparatus  2160  is arranged to be positioned near the end face  202  of the casing  209  by way of example. 
     With the above configuration, the antenna apparatus  2160  according to the fourth variant can transmit or receive a plurality of polarized waves with mutually different polarization directions also in a case where the dipole antennas  2161  capable of transmitting or receiving only one polarized wave are applied. 
     Additionally, if one or more dipole antennas  2161   a  and  2161   b  are each provided, the numbers of dipole antennas  2161   a  and  2161   b  are not particularly limited. However, it is desirable that a plurality of dipole antennas  2161   a  and  2161   b  is each provided as in the communication apparatus  213  according to the first variant in a case where beam forming is used. 
     An exemplary configuration of the antenna apparatus has been described above according to the fourth variant with reference to  FIG. 12  and  FIG. 13  in a case where dipole antennas are used as antenna devices. 
     (Fifth Variant: Exemplary Configuration in a Case where Notch Antenna is Applied) 
     An exemplary configuration of an antenna apparatus according to a fifth variant will be subsequently described in a case where a notch antenna is applied as an antenna device. 
     An outline of a notch antenna will be first described with reference to  FIG. 14 .  FIG. 14  is an explanatory diagram for explaining an outline of a notch antenna. 
     As illustrated in  FIG. 14 , a notch antenna  2171  is configured of a slit  2173  formed on a ground plane  2179  including a conductive material, a power supply line  2175  provided to cross the slit  2173 , and a power supply point  2177  provided at one end of the power supply line  2175 . With the configuration, a current flows along the power supply line  2175  provided to cross the slit  2173  in response to power supplied from the power supply point  2177  in the notch antenna  2171 . That is, the notch antenna  2171  can transmit or receive a polarized wave the polarization direction of which substantially matches with a direction in which the power supply line  2175  extends. 
     An exemplary configuration of an antenna apparatus in which the notch antenna  2171  described with reference to  FIG. 14  is applied as an antenna device will be described with reference to  FIG. 15  according to the above description.  FIG. 15  is a diagram illustrating an exemplary configuration of an antenna apparatus according to the fifth variant. Additionally,  FIG. 15  illustrates an exemplary schematic configuration of an antenna apparatus  2170  viewed in the normal direction of a face in a case where the antenna apparatus  2170  according to the fifth variant is held to be positioned near the face (such as part of the outer faces of the casing  209 ). That is, the antenna apparatus  2170  illustrated in  FIG. 15  mainly transmits or receives wireless signals propagating in a direction substantially matching with the depth direction of  FIG. 15 . 
     As described above, the notch antenna  2171  can transmit or receive a polarized wave the polarization direction of which substantially matches with the direction in which the power supply line  2175  provided to cross the slit  2173  formed on the ground plane  2179  including a conductive material extends. Thus, a plurality of slits extending in mutually different directions is provided on the ground plane  2179  so that the antenna apparatus  2170  illustrated in  FIG. 15  is provided with a plurality of notch antennas  2171  (or notch antennas  2171   a  and  2171   b ). 
     Specifically, the notch antenna  2171   a  is formed with the slit  2173  to vertically extend in  FIG. 15 , and is provided with the power supply line  2175  to cross the slit  2173 . That is, the notch antenna  2171   a  can transmit or receive the polarized wave R H  the polarization direction of which substantially matches with the horizontal direction of  FIG. 15  in wireless signals transmitted or received by the antenna apparatus  2170 . 
     To the contrary, the notch antenna  2171   b  is formed with the slit  2173  to horizontally extend in  FIG. 15 , and is provided with the power supply line  2175  to cross the slit  2173 . That is, the notch antenna  2171   b  can transmit or receive the polarized wave R V  the polarization direction of which substantially matches with the vertical direction of  FIG. 15  in wireless signals transmitted or received by the antenna apparatus  2170 . 
     With the above configuration, the antenna apparatus  2170  according to the fifth variant can transmit or receive a plurality pf polarized waves with mutually different polarization directions also in a case where the notch antennas  2171  capable of transmitting or receiving only one polarized wave are applied. 
     Additionally, if one or more notch antennas  2171   a  and  2171   b  are each formed, the numbers of notch antennas  2171   a  and  2171   b  are not particularly limited. However, it is desirable that a plurality of notch antennas  2171   a  and  2171   b  is each formed, as in the communication apparatus  213  according to the first variant in a case where beam forming is used. 
     An exemplary configuration of the antenna apparatus has been described above according to the fifth variant with reference to  FIG. 14  and  FIG. 15  in a case where notch antennas are applied as antenna devices. 
     (Sixth Variant: Exemplary Configuration in a Case where Monopole Antenna is Applied) 
     An exemplary configuration of an antenna apparatus will be subsequently described according to a sixth variant in a case where a monopole antenna is applied as an antenna device. 
     An outline of a monopole antenna will be first described with reference to  FIG. 16 .  FIG. 16  is an explanatory diagram for explaining an outline of a monopole antenna. 
     As illustrated in  FIG. 16 , a monopole antenna  2181  is configured of a rod-shaped element  2183  formed to extend from a ground plane  2189  including a conductive material, and a power supply point  2185  provided to be positioned on an end of the element  2183  closer to the ground plane  2189 . With the configuration, a current flows along the rod-shaped element  2183  in response to power supplied from the power supply point  2185  in the monopole antenna  2181 . That is, the monopole antenna  2181  can transmit or receive a polarized wave the polarization direction of which substantially matches with a direction in which the rod-shaped element  2183  extends. 
     An exemplary configuration of an antenna apparatus in which the monopole antenna  2181  described with reference to  FIG. 16  is applied as an antenna device will be described with reference to  FIG. 17  according to the above description.  FIG. 17  is a diagram illustrating an exemplary configuration of an antenna apparatus according to the sixth variant. Additionally,  FIG. 17  illustrates an exemplary schematic configuration of an antenna apparatus  2180  viewed in the normal direction of a face in a case where the antenna apparatus  2180  according to the sixth variant is held to be positioned near the face (such as part of the outer faces of the casing  209 ). That is, the antenna apparatus  2180  illustrated in  FIG. 17  mainly transmits or receives wireless signals propagating in a direction substantially matching with the depth direction of  FIG. 17 . 
     As described above, the monopole antenna  2181  can transmit or receive a polarized wave the polarization direction of which substantially matches with the direction in which the rod-shaped element  2183  extends. In other words, a current flows in the rod-shaped element  2183  in one direction, and thus the monopole antenna  2181  itself can transmit or receive only one polarized wave. On the other hand, a plurality of antenna devices is arranged in consideration of the directions of polarized waves transmittable or receivable by the respective antenna devices on the basis of the similar spirit to the third variant, thereby transmitting or receiving polarized waves with mutually different polarization directions similarly to the patch antenna. Thus, a plurality of monopole antennas  2181  (or monopole antennas  2181   a  and  2181   b ) is provided to be able to transmit or receive polarized waves with mutually different polarization directions in the antenna apparatus  2180  illustrated in  FIG. 17 . 
     Specifically, the monopole antenna  2181   a  is formed with the rod-shaped element  2183  to horizontally extend in  FIG. 17 . That is, the monopole antenna  2181   a  can transmit or receive the polarized wave R H  the polarization direction of which substantially matches with the horizontal direction of  FIG. 17  in wireless signals transmitted or received by the antenna apparatus  2180 . 
     To the contrary, the monopole antenna  2181   b  is formed with the rod-shaped element  2183  to vertically extend in  FIG. 17 . That is, the monopole antenna  2181   b  can transmit or receive the polarized wave R V  the polarization direction of which substantially matches with the vertical direction of  FIG. 17  in wireless signals transmitted or received by the antenna apparatus  2180 . 
     With the above configuration, the antenna apparatus  2180  according to the sixth variant can transmit or receive a plurality of polarized waves with mutually different polarization directions also in a case where the monopole antennas  2181  capable of transmitting or receiving only one polarized wave are applied. 
     Additionally, if one or more monopole antennas  2181   a  and  2181   b  are each provided, the numbers of monopole antennas  2181   a  and  2181   b  are not particularly limited. However, it is desirable that a plurality of monopole antennas  2181   a  and  2181   b  is each provided as in the communication apparatus  213  according to the first variant in a case where beam forming is used. 
     An exemplary configuration of the antenna apparatus has been described above according to the sixth variant with reference to  FIG. 16  and  FIG. 17  in a case where monopole antennas are applied as antenna devices. 
     (Seventh Variant: Exemplary Configuration in a Case where Inverted F-Antenna is Applied) 
     An exemplary configuration of an antenna apparatus according to a seventh variant will be subsequently described in a case where an inverted F-antenna is applied as an antenna device. 
     An outline of an inverted F-antenna will be first described with reference to  FIG. 18 .  FIG. 18  is an explanatory diagram for explaining an outline of an inverted F-antenna. 
     As illustrated in  FIG. 18 , an inverted F-antenna  2191  includes an F-shaped element  2193  and a power supply point  2195 . The F-shaped element  2193  is configured of a rod-shaped part separated from an end of a ground plane  2199  and extending along the end, and a part for crossing the rod-shaped part and the ground plane  2199  at two positions of one end of the rod-shaped part. Further, the F-shaped element  2193  is provided with the power supply point  2195  at one of the parts connected with the ground plane  2199 , and the other part operates as a short-circuit point. With the configuration, a current flows along the rod-shaped part separated from an end of the ground plane  2199  and extending along the end in the F-shaped element  2193  in the inverted F-antenna  2191 . That is, the inverted F-antenna  2191  can transmit or receive a polarized wave the polarization direction of which substantially matches with a direction in which the rod-shaped part extends. 
     An exemplary configuration of an antenna apparatus in which the inverted F-antenna  2191  described with reference to  FIG. 18  is applied as an antenna device will be described with reference to  FIG. 19  according to the above description.  FIG. 19  is a diagram illustrating an exemplary configuration of an antenna apparatus according to the seventh variant. Additionally,  FIG. 19  illustrates an exemplary schematic configuration of an antenna apparatus  2190  viewed in the normal direction of a face in a case where the antenna apparatus  2190  according to the seventh variant is held to be positioned near the face (such as part of the outer faces of the casing  209 ). That is, the antenna apparatus  2190  illustrated in  FIG. 19  mainly transmits or receives wireless signals propagating in a direction substantially matching with the depth direction of  FIG. 19 . 
     As described above, the inverted F-antenna  2191  can transmit or receive a polarized wave the polarization direction of which substantially matches with the direction in which the rod-shaped part separated from an end of the ground plane  2199  and extending along the end extends in the F-shaped element  2193 . In other words, a current flows in the rod-shaped part in one direction and thus the inverted F-antenna  2191  itself can transmit or receive only one polarized wave. On the other hand, a plurality of antenna devices is arranged in consideration of the directions of polarized waves transmittable or receivable by the respective antenna devices on the basis of the similar spirit to the third variant, thereby transmitting or receiving polarized waves with mutually different polarization directions similarly to the patch antenna. Thus, a plurality of inverted F-antennas  2191  (or inverted F-antennas  2191   a  and  2191   b ) is provided to be able to transmit or receive polarized waves with mutually different polarization directions in the antenna apparatus  2190  illustrated in  FIG. 19 . 
     Specifically, the inverted F-antenna  2191   a  is arranged such that the direction of the rod-shaped part separated from an end of the ground plane  2199  and extending along the end extends substantially matches with the horizontal direction of  FIG. 19  in the F-shaped element  2193 . That is, the inverted F-antenna  2191   a  can transmit or receive the polarized wave RN the polarization direction of which substantially matches with the horizontal direction of  FIG. 19  in wireless signals transmitted or received by the antenna apparatus  2190 . 
     To the contrary, the inverted F-antenna  2191   b  is arranged such that the direction in which the rod-shaped part separated from an end of the ground plane  2199  and extending along the end extends substantially matches with the vertical direction of  FIG. 19  in the F-shaped element  2193 . That is, the inverted F-antenna  2191   b  can transmit or receive the polarized wave R V  the polarization direction of which substantially matches with the vertical direction of  FIG. 19  in wireless signals transmitted or received by the antenna apparatus  2190 . 
     With the above configuration, the antenna apparatus  2190  according to the seventh variant can transmit or receive a plurality of polarized waves with mutually different polarization directions in a case where the inverted F-antennas  2191  capable of transmitting or receiving only one polarized wave are applied. 
     Additionally, if one or more inverted F-antennas  2191   a  and  2191   b  is each provided, the numbers of inverted F-antennas  2191   a  and  2191   b  are not particularly limited. However, it is desirable that a plurality of inverted F-antennas  2191   a  and  2191   b  is each provided as in the communication apparatus  213  according to the first variant in a case where beam forming is used. 
     An exemplary configuration of the antenna apparatus according to the seventh variant has been described above with reference to  FIG. 18  and  FIG. 19  in a case where the inverted F-antennas are applied as antenna devices. 
     (Eighth Variant: Exemplary Configuration in a Case where Loop Antenna is Applied) 
     An exemplary configuration of an antenna apparatus according to an eighth variant will be subsequently described in a case where a loop antenna is applied as an antenna device. 
     An outline of a loop antenna will be first described with reference to  FIG. 20 .  FIG. 20  is an explanatory diagram for explaining an outline of a loop antenna. 
     As illustrated in  FIG. 20 , a loop antenna  2201  is configured of an annular (loop-shaped) element  2203  and a power supply point  2205 . The element  2203  is formed as an annular (loop-shaped) coil with an elongated conductor, and its respective ends are connected to a ground plane  2209  at mutually different positions. Further, the power supply point  2205  is provided at one end of the respective ends (or the ends connected to the ground plane  2209 ) of the element  2203 . With the configuration, a current flows in a direction in which the annular element  2203  extends in the loop antenna  2201 . With the property, the loop antenna  2201  can transmit or receive two polarized waves with mutually different polarization directions depending on the shape of the element  2203 , but only one power supply point  2205  is provided and thus the two polarized waves are difficult to discriminate. 
     An exemplary configuration of an antenna apparatus in which the loop antenna  2201  described with reference to  FIG. 20  is applied as an antenna device will be described with reference to  FIG. 21  according to the above description.  FIG. 21  is a diagram illustrating an exemplary configuration of an antenna apparatus according to the eighth variant. Additionally,  FIG. 21  illustrates an exemplary schematic configuration of an antenna apparatus  2200  viewed in the normal direction of a face in a case where the antenna apparatus  2200  according to the eighth variant is held to be positioned near the face (such as part of the outer faces of the casing  209 ). That is, the antenna apparatus  2200  illustrated in  FIG. 21  mainly transmits or receives wireless signals propagating in a direction substantially matching with the depth direction of  FIG. 21 . 
     As illustrated in  FIG. 21 , the element  2203  forms a square loop and a plurality of loop antennas  2201  (or loop antennas  2201   a  and  2201   b ) with mutually different aspect ratios of the element  2203  is provided in the antenna apparatus  2200 . 
     Specifically, the loop antenna  2201   a  is formed with the element  2203  such that a direction in which the ground plane  2209  extends (or the horizontal direction of  FIG. 21 ) is the longitudinal direction. Thereby, the loop antenna  2201   a  more dominantly transmits or receives the polarized wave R H  the polarization direction of which substantially matches with the longitudinal direction than the polarized wave R V  the polarization direction of which substantially matches with the short direction. That is, the loop antenna  2201   a  can transmit or receive the polarized wave R H  in wireless signals transmitted or received by the antenna apparatus  219 ). 
     To the contrary, the loop antenna  2201   b  is formed with the element  2203  such that a direction (or the vertical direction of  FIG. 21 ) orthogonal to the direction in which the ground plane  2209  extends is the longitudinal direction. Thereby, the loop antenna  2201   b  more dominantly transmits or receives the polarized wave R v  the polarization direction of which substantially matches with the longitudinal direction than the polarized wave R H  the polarization direction of which substantially matches with the short direction. That is, the loop antenna  2201   b  can transmit or receive the polarized wave R V  in wireless signals transmitted or received by the antenna apparatus  2190 . 
     With the above configuration, the antenna apparatus  2200  according to the eighth variant can discriminate and transmit or receive each of a plurality of polarized waves with mutually different polarization directions also in a case where the loop antennas  2201  are applied. 
     Additionally, if one or more loop antennas  2201   a  and  2201   b  are each provided, the numbers of loop antennas  2201   a  and  2201   b  are not particularly limited. However, it is desirable that a plurality of loop antennas  2201   a  and  2201   b  are each provided as in the communication apparatus  213  according to the first variant in a case where beam forming is used. 
     An exemplary configuration of the antenna apparatus according to the eighth variant has been described above with reference to  FIG. 20  and  FIG. 21  in a case where the loop antennas are applied as antenna devices. 
     (Ninth Variant: Exemplary Configuration in a Case where Slot Antenna is Applied) 
     An exemplary configuration of an antenna apparatus according to a ninth variant will be subsequently described in a case where a slot antenna is applied as an antenna device. 
     An outline of a slot antenna will be first described with reference to  FIG. 22 .  FIG. 22  is an explanatory diagram for explaining an outline of a slot antenna. 
     As illustrated in  FIG. 22 , a slot antenna  2211  is configured of an elongated slot  2213  (or elongated cutout) formed on a ground plane  2219  including a conductive material, a power supply line  2215 , and a power supply point  2217 . The power supply line  2215  is provided to cross the ends extending in the longitudinal direction of the slot  2213 . Further, the power supply point  2217  is provided at one end of the power supply line  2215 . With the configuration, a current flows along the power supply line  2215  provided to cross the slot  2213  in the slot antenna  2211 . That is, the slot antenna  2211  can transmit or receive a polarized wave the polarization direction of which substantially matches with a direction in which the power supply line  2215  extends. 
     An exemplary configuration of an antenna apparatus in which the slot antenna  2211  described with reference to  FIG. 22  is applied as an antenna device will be described with reference to  FIG. 23  according to the above description.  FIG. 23  is a diagram illustrating an exemplary configuration of an antenna apparatus according to the ninth variant. Additionally,  FIG. 23  illustrates an exemplary schematic configuration of an antenna apparatus  2210  viewed in the normal direction of a face in a case where the antenna apparatus  2210  according to the ninth variant is held to be positioned near the face (such as part of the outer faces of the casing  209 ). That is, the antenna apparatus  2210  illustrated in  FIG. 23  can transmit or receive wireless signals propagating in a direction substantially matching with the depth direction of  FIG. 23 . 
     As described above, the slot antenna  2211  can transmit or receive a polarized wave the polarization direction of which substantially matches with the direction in which the power supply line  2215  provided to cross the slot  2213  formed on the ground plane  2219  including a conductive material extends. Thus, a plurality of slots extending in mutually different directions is provided on the ground plane  2219 , and thus the antenna apparatus  2210  illustrated in  FIG. 23  is provided with a plurality of slot antennas  2211  (or slot antennas  2211   a  and  2211   b ). 
     Specifically, the slot antenna  2211   a  is formed with the slot  2213  extending in the vertical direction of  FIG. 23 , and is provided with the power supply line  2215  to cross the slot  2213 . That is, the slot antenna  2211   a  can transmit or receive the polarized wave R f  the polarization direction of which substantially matches with the horizontal direction of  FIG. 23  in wireless signals transmitted or received by the antenna apparatus  2210 . 
     To the contrary, the slot antenna  2211   b  is formed with the slot  2213  extending in the horizontal direction of  FIG. 23 , and is provided with the power supply line  2215  to cross the slot  2213 . That is, the slot antenna  2211   b  can transmit or receive the polarized wave R V  the polarization direction of which substantially matches with the vertical direction of  FIG. 23  in wireless signals transmitted or received by the antenna apparatus  2210 . 
     With the above configuration, the antenna apparatus  2210  according to the ninth variant can transmit or receive a plurality of polarized waves with mutually different polarization directions also in a case where the slot antennas  2211  capable of transmitting or receiving only one polarized wave are applied. 
     Additionally, if one or more slot antennas  2211   a  and  2211   b  are each formed, the numbers of slot antennas  2211   a  and  2211   b  are not particularly limited. However, it is desirable that a plurality of slot antennas  2211   a  and  2211   b  is each formed as in the communication apparatus  213  according to the first variant in a case where beam forming is used. 
     An exemplary configuration of the antenna apparatus according to the eighth variant has been described above with reference to  FIG. 22  and  FIG. 23  in a case where the loop antennas are applied as antenna devices. 
     3.4. EXAMPLES 
     Examples of the communication apparatus (such as the terminal apparatus  200 ) according to the present embodiment will be subsequently described. As described above, a millimeter wave tends to be easily reflected on a human body. To the contrary, a portable communication apparatus (such as the terminal apparatus  200 ) such as Smartphone is used while its casing is being held in a hand in many cases. Thus, when a communication path directly connecting an antenna device provided in a terminal apparatus and a base station is blocked by a site such as a hand holding the casing of the terminal apparatus, a millimeter wave propagating in the communication path is blocked by the site such as a hand. Exemplary antenna apparatus installation positions will be described according to the present examples in terms of such a situation assuming that a user holds a terminal apparatus. 
     First Example: First Exemplary Configuration Assuming Vertical Holding 
     An exemplary antenna apparatus installation position according to a first example will be first described with reference to  FIG. 24  and  FIG. 25  assuming that a communication apparatus is vertically held.  FIG. 24  and  FIG. 25  are explanatory diagrams for explaining an outline of a communication apparatus according to the first example. Additionally. “vertical holding” in the following description indicates that a communication apparatus including a casing with a substantially rectangular face such as the terminal apparatus  200  is held such that that the longitudinal direction of the face substantially matches with the vertical direction of a user. Further, to the contrary, how the communication apparatus is held such that the longitudinal direction of the face substantially matches with the horizontal direction of the user is also called “horizontal holding”. 
     For example,  FIG. 24  illustrates how a communication apparatus (such as the terminal apparatus  200 ) such as Smartphone is vertically held by way of example. Specifically, in the example illustrated in  FIG. 24 , the user holds the lower end in the longitudinal direction of the casing  209  of the terminal apparatus  200  by a hand U 111 . 
     Further,  FIG. 25  is a diagram schematically illustrating a part blocked by a user&#39;s hand in the respective parts of the terminal apparatus  200  in a case where the terminal apparatus  200  is held as illustrated in  FIG. 24 . Additionally, the communication apparatus according to the first example may be denoted as “communication apparatus  231 ” in the following description in order to discriminate from the communication apparatuses according to the above embodiment and the respective variants or the communication apparatuses according to the other examples. 
     The reference numerals  201  to  205  in  FIG. 25  correspond to the backside  201  and the end faces  202  to  205  of the casing  209 , respectively, in the example described with reference to  FIG. 5 . Further, a reference numeral U 113  schematically illustrates a region blocked by a users hand (or the hand U 111  illustrated in  FIG. 24 ). 
     That is, particularly in a case where the lower part is held as illustrated in  FIG. 24  while the communication apparatus  231  is vertically held, even if an antenna apparatus is provided in the region U 113 , a millimeter wave is difficult to transmit or receive by the antenna apparatus. Assuming the case, an antenna apparatus may be provided at an upper part in a case where the communication apparatus  231  is vertically held as illustrated in  FIG. 25 , for example. For example, a reference numeral  2310  in  FIG. 25  schematically illustrates an antenna apparatus provided in the communication apparatus  231  according to the present example. 
     Further, in the example illustrated in  FIG. 25 , even if an antenna apparatus is installed in the region U 113 , the antenna apparatus hardly contributes to an enhancement in communication property in communication using millimeter waves. Thus, assuming that the communication apparatus  231  is held as illustrated in  FIG. 24 , an antenna apparatus positioned within the region U 113  illustrated in  FIG. 25  may be temporarily disabled or an antenna apparatus may not be provided within the region U 113 , for example. Additionally, which part of the casing  209  the user holds can be dynamically recognized by use of a sensor for detecting an approach of a human body such as capacitive sensor, for example. Further, an orientation (or vertical holding or horizontal holding) of the casing  209  can be dynamically recognized by use of various sensors such as gravity sensor, acceleration sensor, and angular speed sensor, for example. 
     Additionally, the vertical direction may be explicitly determined in a case where a communication apparatus such as Smartphone is vertically held. As a specific example, in a case where the vertical direction of a communication apparatus is explicitly determined while the communication apparatus is vertically held, the screen displayed on the display is not inverted and the display is maintained even if the vertical direction is inverted, for example. With the configuration, it is expected that the user holds the communication apparatus such that the vertical direction of the communication apparatus substantially matches with the vertical direction of the user in many cases while he/she vertically holds the communication apparatus. 
     In a case where the vertical direction of the communication apparatus is explicitly determined in vertical holding in this way, it is better that at least one antenna apparatus  2310  is held to be positioned on the upper side of the communication apparatus while the communication apparatus is vertically held. 
     Further, the lower half of a communication apparatus is held in many cases while the communication apparatus is vertically held. Assuming the case, it is better that the antenna apparatus  2310  positioned in the horizontal direction of the communication apparatus is held to be positioned on the upper half side of the communication apparatus while the communication apparatus is vertically held, for example. 
     An exemplary antenna apparatus installation position according to the first example has been described above with reference to  FIG. 24  and  FIG. 25  assuming that a communication apparatus is vertically held. 
     Second Example: Second Exemplary Configuration Assuming Vertical Holding 
     Other exemplary antenna apparatus installation position assuming that a communication apparatus is vertically held will be subsequently described according to a second example with reference to  FIG. 26  and  FIG. 27 .  FIG. 26  and  FIG. 27  are explanatory diagrams for explaining an outline of a communication apparatus according to the second example. 
     For example,  FIG. 26  illustrates other example in which a communication apparatus (such as the terminal apparatus  200 ) such as Smartphone is vertically held. Specifically, in the example illustrated in  FIG. 26 , the user grips around the centers of both ends in the short direction of the casing  209  of the terminal apparatus  200  with a hand U 115 . 
     Further,  FIG. 27  is a diagram schematically illustrating a part blocked by a user&#39;s hand in the respective parts of the terminal apparatus  200  in a case where the terminal apparatus  200  is held as illustrated in  FIG. 26 . Additionally, the communication apparatus according to the second example may be dented as “communication apparatus  232 ” in the following description in order to discriminate from the communication apparatuses according to the above embodiment and the respective variants or the communication apparatuses according to the other examples. 
     The reference numerals  201  to  205  in  FIG. 27  correspond to the backside  201  and the end faces  202  to  205  of the casing  209 , respectively, in the example described with reference to  FIG. 5 . Further, the reference numeral U 115  schematically illustrates a region blocked by a user&#39;s hand (or the hand U 113  illustrated in  FIG. 26 ). 
     That is, particularly in a case where around the centers of both ends (or the end faces  203  and  205 ) in the short direction are held with a hand as illustrated in  FIG. 26  while the communication apparatus  232  is vertically held, a millimeter wave is difficult to transmit or receive by an antenna apparatus even if the antenna apparatus is provided in the region U 115 . Assuming the case, for example, antenna apparatuses may be provided at the upper and lower positions as illustrated in  FIG. 27  while the communication apparatus  231  is vertically held. For example, a reference numeral  2320  in  FIG. 27  schematically illustrates an antenna apparatus provided in the communication apparatus  232  according to the present example. 
     Further, in the example illustrated in  FIG. 27 , even if an antenna apparatus is installed in the region U 115 , the antenna apparatus hardly contributes to an enhancement in communication property in communication using millimeter waves. Thus, assuming that the communication apparatus  232  is held as illustrated in  FIG. 26 , an antenna apparatus positioned in the region U 115  illustrated in  FIG. 27  may be temporarily disabled or an antenna apparatus may not be provided within the region U 115 , for example. 
     Other exemplary antenna apparatus installation position assuming that the communication apparatus is vertically held has been described above according to the second example with reference to  FIG. 26  and  FIG. 27 . 
     Third Example: Third Exemplary Configuration Assuming Vertical Holding 
     Other exemplary antenna apparatus installation position assuming that a communication apparatus is vertically held will be subsequently described according to a third example with reference to  FIG. 28  and  FIG. 29 .  FIG. 28  and  FIG. 29  are explanatory diagrams for explaining an outline of a communication apparatus according to the third example. 
     For example,  FIG. 28  illustrates other example in which a communication apparatus (such as the terminal apparatus  200 ) such as Smartphone is vertically held. Specifically, in the example illustrated in  FIG. 28 , the user grips around the centers of both ends in the short direction of the casing  209  of the terminal apparatus  200  with a hand U 119 . Further, in the example illustrated in  FIG. 28 , a sound collection part such as microphone is provided on the lower side of the communication apparatus, and the user holds the communication apparatus such that the lower side is positioned near the head U 121  (particularly the mouth) of the user. 
     Further,  FIG. 29  is a diagram schematically illustrating a part blocked by a user&#39;s hand in the respective parts of the terminal apparatus  200  and a part positioned near the head of the user in a case where the terminal apparatus  200  is held as illustrated in  FIG. 28 . Additionally, the communication apparatus according to the third example may be denoted as “communication apparatus  233 ” in the following description in order to discriminate from the communication apparatuses according to the above embodiment and the respective variants or the communication apparatuses according to the other examples. 
     The reference numerals  201  to  205  in  FIG. 29  correspond to the backside  201  and the end faces  202  to  205  of the casing  209 , respectively, in the example described with reference to  FIG. 5 . Further, a reference numeral U 123  schematically illustrates a region blocked by a user&#39;s hand (or the hand U 119  illustrated in  FIG. 28 ). Further, a reference numeral U 125  schematically illustrates a region positioned near the head (the head U 121  illustrated in  FIG. 28 ) of the user. 
     That is, particularly in a case where around the centers of both ends (or the end faces  203  and  205 ) in the short direction are held with a hand as illustrated in  FIG. 28  while the communication apparatus  233  is vertically held, a millimeter wave is difficult to transmit or receive by an antenna apparatus even if the antenna apparatus is provided in the region U 123 . Further, the legally-defined conditions for human body, particularly the head may be severer than those for other sites in terms of human body protection from wireless signals (particularly millimeter waves). Assuming the case, for example, an antenna apparatus may be provided at an upper part as illustrated in  FIG. 29  in a case where the communication apparatus  231  is vertically held. For example, a reference numeral  2330  in  FIG. 29  schematically illustrates an antenna apparatus provided in the communication apparatus  233  according to the present example. 
     Further, in the example illustrated in  FIG. 29 , even if an antenna apparatus is installed in the region U 123 , the antenna apparatus hardly contributes to an enhancement in communication property in communication using millimeter waves. Thus, assuming that the communication apparatus  233  is held as illustrated in  FIG. 28 , for example, an antenna apparatus positioned within the region U 123  illustrated in  FIG. 29  may be temporarily disabled, or an antenna apparatus may not be provided within the region U 123 . 
     Further, in consideration of influences on human body by wireless signals, a region where the sound collection part such as microphone is provided, such as the region U 125 , is positioned near the head of the user depending on a situation. In terms of such a situation, it may be desirable that the antenna apparatus provided in the region U 125  is not used for communication using millimeter waves. Thus, assuming that the communication apparatus  233  is held as illustrated in  FIG. 28 , an antenna apparatus positioned within the region U 125  illustrated in  FIG. 29  may be temporarily disabled or an antenna apparatus may not be provided within the region U 125 , for example. 
     Other exemplary antenna apparatus installation position assuming that the communication apparatus is vertically held has been described above according to the third example with reference to  FIG. 28  and  FIG. 29 . 
     Fourth Example: Exemplary Configuration Assuming Horizontal Holding 
     An exemplary antenna apparatus installation position assuming that a communication apparatus is horizontally held will be subsequently described according to a fourth example with reference to  FIG. 30  to  FIG. 32 .  FIG. 30  to  FIG. 32  are explanatory diagrams for explaining an outline of a communication apparatus according to the fourth example. 
     Specifically,  FIG. 30  to  FIG. 32  particularly illustrate that the user holds a communication apparatus to oppose a display part  207  (such as display) provided on the top side  206  of the casing  209  of the communication apparatus in a case where the communication apparatus (such as the terminal apparatus  200 ) such as Smartphone is horizontally held by way of example. Additionally, the communication apparatuses illustrated in  FIG. 30 ,  FIG. 31 , and  FIG. 32  may be denoted as “communication apparatus  234 ”, “communication apparatus  235 ”, and “communication apparatus  236 ”, respectively, in the present invention in order to discriminate from the communication apparatuses according to the above embodiment and the respective variants or the communication apparatuses according to the other examples. Further, the reference numerals  202  to  205  in each of  FIG. 30  to  FIG. 32  correspond to the end faces  202  to  205  of the casing  20 ) in the example described with reference to  FIG. 5 . Further, the reference numeral  206  indicates the top side of the casing  209 , and the reference numeral  207  indicates a display part (display) provided on the top side  206 . 
     The example illustrated in  FIG. 30  will be first described. The example illustrated in  FIG. 30  illustrates that the end face  204  positioned on the right side viewed from a user is held with a user&#39;s hand (such as the right hand) such that the end face  205  is positioned upward viewed from the user by way of example. Further, a reference numeral U 127  in  FIG. 30  schematically illustrates a region blocked by a user&#39;s hand. 
     Particularly in a case where the end face  204  is held with a hand as illustrated in  FIG. 30  while the communication apparatus  234  is horizontally held, a millimeter wave is difficult to transmit or receive by an antenna apparatus even if the antenna apparatus is provided in the region U 127 . Assuming the case, for example, antenna apparatuses may be provided at the upper, lower, and left positions viewed from the user as illustrated in  FIG. 30  in a case where the communication apparatus  234  is horizontally held. For example, a reference numeral  2340  in  FIG. 30  schematically illustrates an antenna apparatus provided in the communication apparatus  234  illustrated in  FIG. 30  in the communication apparatuses according to the present example. 
     Further, in the example illustrated in  FIG. 30 , an antenna apparatus hardly contributes to an enhancement in communication property in communication using millimeter waves even if the antenna apparatus is installed in the region U 127 . Thus, assuming that the communication apparatus  234  is held as illustrated in  FIG. 30 , an antenna apparatus positioned within the region U 127  illustrated in  FIG. 30  may be temporarily disabled or an antenna apparatus may not be provided within the region U 127 , for example. 
     The example illustrated in  FIG. 31  will be described below. The example illustrated in  FIG. 31  illustrates that the end face  202  positioned on the left side viewed from the user is held with a users hand (such as the left hand) such that the end face  205  is positioned upward viewed from the user by way of example. Further, a reference numeral U 129  in  FIG. 31  schematically illustrates a region blocked by a users hand. 
     Particularly in a case where the end face  202  is held with a hand as illustrated in  FIG. 31  while the communication apparatus  235  is horizontally held, a millimeter wave is difficult to transmit or receive by an antenna apparatus even if the antenna apparatus is provided in the region U 129 . Assuming the case, for example, in a case where the communication apparatus  235  is horizontally held as illustrated in  FIG. 31 , antenna apparatuses may be provided on the upper, lower, and right positions viewed from the user. For example, a reference numeral  2350  in  FIG. 31  schematically illustrates an antenna apparatus provided in the communication apparatus  235  illustrated in  FIG. 31  in the communication apparatuses according to the present example. 
     Further, in the example illustrated in  FIG. 31 , an antenna apparatus hardly contributes to an enhancement in communication property in communication using millimeter waves even if the antenna apparatus is installed in the region U 129 . Thus, assuming that the communication apparatus  235  is held as illustrated in  FIG. 31 , an antenna apparatus positioned within the region U 129  illustrated in  FIG. 31  may be temporarily disabled or an antenna apparatus may not be provided within the region U 129 , for example. 
     The example illustrated in  FIG. 32  will be described below. The example illustrated in  FIG. 32  illustrates that both the end faces  202  and  204  positioned on the left and right sides viewed from the user are held with user&#39;s hands (such as both hands) such that the end face  205  is positioned upward viewed from the user by way of example. Further, the reference numerals U 127  and U 129  in  FIG. 32  schematically illustrate regions blocked by the users hands, respectively. 
     Particularly in a case where both the end faces  202  and  204  are held by both hands as illustrated in  FIG. 32  while the communication apparatus  236  is horizontally held, a millimeter wave is difficult to transmit or receive by antenna apparatuses even if the antenna apparatuses are provided in the regions U 127  and U 129 . Assuming the case, for example, in a case where the communication apparatus  236  is horizontally held as illustrated in  FIG. 32 , antenna apparatuses may be provided at the upper and lower positions viewed from the user. For example, a reference numeral  2360  in  FIG. 32  schematically illustrates an antenna apparatus provided in the communication apparatus  236  illustrated in  FIG. 32  in the communication apparatuses according to the present example. 
     Further, in the example illustrated in  FIG. 32 , antenna apparatuses hardly contribute to an enhancement in communication property in communication using millimeter waves even if the antenna apparatuses are installed in the regions U 127  and U 129 , respectively. Thus, assuming that the communication apparatus  236  is held as illustrated in  FIG. 32 , the antenna apparatuses positioned in the regions U 1127  and U 129  illustrated in  FIG. 32  may be temporarily disabled or an antenna apparatus may not be provided in the regions U 127  and U 129 , for example. 
     An exemplary antenna apparatus installation position assuming that the communication apparatus is horizontally held has been described above according to the fourth example with reference to  FIG. 30  to  FIG. 32 . 
     Fifth Example: Configuration Assuming Predetermined Device Installation Position 
     An exemplary antenna apparatus installation position assuming a predetermined device installation position will be subsequently described according to a fifth example with reference to  FIG. 33  and  FIG. 34 .  FIG. 33  and  FIG. 34  are explanatory diagrams for explaining an outline of a communication apparatus according to the fifth example. 
     Specifically, a form in which a communication apparatus is held (or how to hold a communication apparatus) may be limited for some devices among various devices provided in the communication apparatus depending on the positions where the devices are installed in order to cause the devices to function. 
     For example,  FIG. 33  illustrates an exemplary antenna apparatus installation position assuming a position where a display part such as display is installed. Additionally, particularly the communication apparatus illustrated in  FIG. 33  among the communication apparatuses according to the fifth example may be denoted as “communication apparatus  237 ” in the following description in order to discriminate from the communication apparatuses according to the above embodiment and the respective variants or the communication apparatuses according to the other examples. 
     The reference numerals  202  to  205  in  FIG. 33  correspond to the end faces  202  to  205  of the casing  209  in the example described with reference to  FIG. 5 . Further, the reference numeral  206  indicates the top side of the casing  20 ), and the reference numeral  207  indicates a display part (display) provided on the top side  206 . Additionally, the example illustrated in  FIG. 33  schematically illustrates a state in which the user horizontally holds the communication apparatus  237  in order to view a video such as moving picture by use of the communication apparatus  237 . More specifically, in the example illustrated in  FIG. 33 , both the end faces  202  and  204  positioned on the left and right sides viewed from the user are held by user&#39;s hands (such as both hands) such that the end face  205  is positioned upward viewed from the user. That is, the reference numerals U 127  and U 129  schematically illustrate the regions blocked by the user&#39;s hands, respectively. 
     As illustrated in  FIG. 33 , when at least part of the display part  207  displaying a video thereon is held with a hand or the like while the user views the video such as moving picture, the display part  207  is blocked by the hand or the like. Thus, it is expected that the communication apparatus  237  is less likely to be held to block the display part  207 . Further, the screen of video contents such as movie or game is configured such that the horizontal direction is longer than the vertical direction in many cases, and the communication apparatus  237  is likely to be horizontally held while a video content is viewed. Additionally, for horizontal holding, the end face  205  may be held upward as illustrated in  FIG. 33 , or the end face  203  may be held upward. 
     In terms of the above situation, the regions denoted with a reference numeral  2370 , or the parts extending along the ends in the longitudinal direction of the display part  207  on the end faces  203  and  205  are less likely to be blocked by user&#39;s hands or the like. Thus, an antenna apparatus is held in at least part of the regions  2370 , and thus the communication apparatus is likely to contribute to an enhancement in communication property in communication using millimeter waves. 
     Further,  FIG. 34  illustrates an exemplary antenna apparatus installation position assuming a position where an antenna used for non-contact communication such as near field radio communication (NFC) is installed. Additionally, particularly the communication apparatus illustrated in  FIG. 34  in the communication apparatuses according to the fifth example may be denoted as “communication apparatus  238 ” in the following description in order to discriminate from the communication apparatuses according to the above embodiment and the respective variants or the communication apparatuses according to the other examples. 
     The reference numerals  201  to  205  in  FIG. 33  correspond to the backside  201  and the end faces  202  to  205  of the casing  209 , respectively, in the example described with reference to  FIG. 5 . Additionally, the example illustrated in  FIG. 33  schematically illustrates a state in which the user horizontally holds the communication apparatus  237  in order to view a video such as moving picture by use of the communication apparatus  237 . Additionally, a reference numeral  208  in  FIG. 34  schematically illustrates an antenna used for non-contact communication. Further, the reference numeral U 113  schematically illustrates a region blocked by a user&#39;s hand. 
     In a case where the user holds the communication apparatus  238  when using non-contact communication, it is assumed that the user holds a different part from the position where the antenna  208  used for the communication is provided. For example, in the example illustrated in  FIG. 34 , the antenna  208  is provided in a region positioned on the upper side viewed from the user in a case where the communication apparatus  238  is vertically held. In such a situation, it is expected that the user holds other different region from the region where the antenna  208  is provided like the region U 113  positioned on the lower side of the communication apparatus  238 , for example, as illustrated in  FIG. 34 . 
     Thus, an antenna apparatus used for communication using millimeter waves (or the antenna apparatus according to the present embodiment) may be provided in a region near the antenna  208  used for non-contact communication, for example. As a more specific example, in a case where the antenna  208  is configured as a loop antenna, for example, the communication apparatus according to the present embodiment may be provided to be positioned on the opening of the element of the antenna  208 . 
     Additionally, the above example is merely exemplary, and does not necessarily limit the antenna apparatus installation position according to the present embodiment. That is, if an antenna apparatus installation position is determined in consideration of a region blocked by a site such as hand depending on the holding method while how to hold the communication apparatus is limited depending on a predetermined device installation position, the kind of the device is not particularly limited, and the antenna apparatus installation position is not limited. 
     An exemplary antenna apparatus installation position assuming a predetermined device installation position has been described above according to the fifth example with reference to  FIG. 33  and  FIG. 34 . 
     Sixth Example: Specific Example of Antenna Apparatus Installation Position 
     A more specific example of an antenna apparatus installation position assuming a portable communication apparatus such as Smartphone will be subsequently described according to a sixth example with reference to  FIG. 35 .  FIG. 35  is an explanatory diagram for explaining an exemplary configuration of a communication apparatus according to the sixth example, and illustrates an exemplary schematic internal structure of the communication apparatus. Additionally, the example illustrated in  FIG. 35  illustrates only some devices for easily understanding the characteristics of the communication apparatus according to the present example, and does not illustrate the other devices. Further, the communication apparatus according to the sixth example may be denoted as “communication apparatus  241 ” in the following description in order to discriminate from the communication apparatuses according to the above embodiment and the respective variants or the communication apparatuses according to the other examples. 
     The reference numerals  202  to  205  in  FIG. 35  correspond to the end faces  202  to  205  of the casing  209 , respectively, in the example described with reference to  FIG. 5 . That is, the upward direction in  FIG. 35  corresponds to the upward direction in a case where the communication apparatus  241  is vertically held. 
     A reference numeral  2411  in  FIG. 35  indicates a universal serial bus (USB) terminal. Further, reference numerals  2412  and  2413  indicate an antenna used for communication based on a standard such as LTE/LTE-A (or communication using an ultrahigh frequency of around 700 MHz to 3.5 GHz). Further, reference numerals  2414  and  2415  indicate an antenna supplementally used for communication based on a standard such as LTE/LTE-A. Further, reference numerals  2418  to  2420  indicate an antenna used for communication based on a standard such as WiFi (registered trademark), an antenna supplementally used for communication based on a standard such as LTE/LTE-A, or the like. Further, reference numerals  2416  and  2417  indicate an input device such as button provided on the end face  205  of the communication apparatus  241 . 
     As illustrated in  FIG. 35 , the USB terminal  2411  or the antenna  2413  used for communication based on a standard such as LTE/LTE-A is arranged near the end face  203  on the lower side of the communication apparatus  241 , and the space therefor is limited. Thus, in the example illustrated in  FIG. 35 , the antenna apparatuses according to the present embodiment are provided to be positioned near the respective end faces (or the end faces  202 ,  203 , and  205 ) other than the end face  204  positioned on the lower side among the end faces  202  to  205  of the casing  209  in the communication apparatus  241 . For example, reference numerals  2421  to  2423  indicate an antenna apparatus according to the present embodiment. Additionally, it is of course desirable that the antenna apparatuses  2421  to  2423  according to the present embodiment are installed to avoid interfering with other devices such as the antennas  2414  and  2415 , the antennas  2418  to  2420 , and the input devices  2416  and  2417  as illustrated in  FIG. 35 . 
     A more specific example of an antenna apparatus installation position assuming a portable communication apparatus such as Smartphone has been described above according to the sixth example with reference to  FIG. 35 . 
     Seventh Example: Configuration Assuming the Use of Accessory 
     An exemplary antenna apparatus installation position assuming the use of an accessory such as so-called holder will be subsequently described according to a seventh example with reference to  FIG. 36 .  FIG. 36  is an explanatory diagram for explaining an outline of a communication apparatus according to the seventh example. 
     For example,  FIG. 36  illustrates an exemplary communication apparatus holding method in a case where an anti-drop ring holder is used. Specifically, in the example illustrated in  FIG. 36 , a ring holder U 133  is attached on the back of the casing of the terminal apparatus  200 , and the user holds the casing of the terminal apparatus  200  with his/her finger through the ring part of the ring holder U 133 . In this way, a form in which the terminal apparatus  200  is held (or how to hold a communication apparatus) may be limited assuming the use of a predetermined accessory. 
     As a more specific example, in the example illustrated in  FIG. 36 , the ring holder U 133  is attached on substantially the center of the back of the casing of the terminal apparatus  200 , and the user holds the terminal apparatus  200  by horizontally gripping around the centers of both ends in the short direction of the casing. Thus, in this case, in a case where the antenna apparatuses according to the present embodiment are provided near both ends in the short direction of the casing, it is better that they are provided to be positioned on the upper side of the casing which is not blocked by a users hand. For example, the reference numeral  2411  schematically illustrates an antenna apparatus according to the present embodiment. 
     Additionally, as described above according to the sixth example, an antenna used for communication based on other standard such as LTE/LTE-A or WiFi may be provided in the communication apparatus in addition to the antenna apparatuses according to the present embodiment. Thus, in a case where the positions where an antenna apparatus can be installed are limited, the communication apparatus may be configured such that the antenna apparatuses according to the present embodiment are present together with an antenna used for communication based on other standard, for example. 
     An exemplary antenna apparatus installation position assuming the use of an accessory such as so-called holder has been described above according to the seventh example with reference to  FIG. 36 . 
     3.5. APPLICATIONS 
     There will be subsequently described exemplary cases in which the technology according to the present disclosure is applied to apparatuses other than the communication terminals such as Smartphone as applications of a communication apparatus according to one embodiment of the present disclosure. 
     In recent years, a technology for connecting various things to a network called Internet of things (IoT) has been paid attention to, and is assumed to be usable in communication by apparatuses other than Smartphone or table terminal. Thus, for example, the technology according to the present disclosure is applied to various mobile apparatuses so that communication using millimeter waves is enabled for the apparatuses, and polarization MIMO can be used for the communication. 
     For example,  FIG. 37  is an explanatory diagram for explaining an application of the communication apparatus according to the present embodiment, and illustrates that the technology according to the present disclosure is applied to a camera device by way of example. Specifically, in the example illustrated in  FIG. 37 , the antenna apparatuses according to one embodiment of the present disclosure are held to be positioned near the respective faces  301  and  302  facing in mutually different directions in the outer faces of the casing of a camera device  300 . For example, a reference numeral  311  schematically illustrates an antenna apparatus according to one embodiment of the present disclosure. With the configuration, the camera device  300  illustrated in  FIG. 37  can transmit or receive a respective plurality of polarized waves propagating in a direction substantially matching with the normal direction of each face and having mutually different polarization directions for the respective faces  301  and  302 , for example. Additionally, the antenna apparatuses  311  may be provided on not only the faces  301  and  302  illustrated in  FIG. 37  but also the other faces. 
     Further, the technology according to the present disclosure can be applied to unmanned aircraft called drone, or the like. For example,  FIG. 38  is an explanatory diagram for explaining an application of the communication apparatus according to the present embodiment, and illustrates that the technology according to the present disclosure is applied to a camera device installed on the lower part of a drone by way of example. Specifically, in the case of a drone flying high, it is desirable that wireless signals (millimeter waves) arriving in each direction can be transmitted or received mainly on the lower side. Thus, for example, in the example illustrated in  FIG. 38 , the antenna apparatuses according to one embodiment of the present disclosure are held to be positioned near each other in mutually different directions on an outer face  401  of a casing of a camera device  400  installed on the lower part of the drone. For example, a reference numeral  411  schematically illustrates an antenna apparatus according to one embodiment of the present disclosure. Further, though not illustrated in  FIG. 38 , not only the camera device  400  but also the antenna apparatuses  411  may be provided in the respective parts of the casing of the drone itself, for example. Also in this case, it is better that the antenna apparatuses  411  are provided particularly on the lower side of the casing. 
     Additionally, in a case where at least pan of the outer face of the casing of an apparatus of interest is curved (or rounded) as illustrated in  FIG. 38 , it is better that the antenna apparatuses  411  are held near a respective plurality of partial regions the normal directions of which cross each other or the normal directions of which are mutually twisted in the respective partial regions in the curved face. With the configuration, the camera device  400  illustrated in  FIG. 38  can transmit or receive a respective plurality of polarized waves propagating in a direction substantially matching with the normal direction of each partial region and having mutually different polarization directions. 
     Additionally, the examples illustrated in  FIG. 37  and  FIG. 38  are merely exemplary, and the technology according to the present disclosure may be applied to apparatuses for communication using millimeter waves, not particularly limited. 
     Examples in which the technology according to the present disclosure is applied to apparatuses other than the communication terminals such as Smartphone have been described above as applications of the communication apparatus according to one embodiment of the present disclosure with reference to  FIG. 37  and  FIG. 38 . 
     4. CONCLUSION 
     As described above, a communication apparatus according to one embodiment of the present disclosure includes a plurality of antenna parts for receiving or transmitting wireless signals, a communication control part for controlling transmitting or receiving wireless signals via at least any of the plurality of antenna parts, and a casing housing the communication control part. Further, the respective plurality of antenna parts is held near a respective plurality of partial regions the normal directions of which cross each other or the normal directions of which are mutually twisted on the outer faces of the casing, and transmits or receives a plurality of polarized waves propagating in a direction substantially orthogonal to each of the partial regions and having mutually different polarization directions. 
     With the configuration, also in a situation in which the position or orientation changes over time like a portable communication apparatus, the communication apparatus can realize polarization MIMO using a direct wave in a more suitable form in communication with other apparatus via a wireless communication path. 
     The preferred embodiments of the present disclosure have been described above in detail with reference to the accompanying drawings, but the technical scope of the present disclosure is not limited to the examples. It is apparent to those skilled in the art in the technical field of the present disclosure that various changes or modifications can be assumed within the scope of the technical spirit described in CLAIMS and these of course belong to the technical scope of the present disclosure. 
     Further, the effects described in the present specification are merely explanatory or exemplary, and are not restrictive. That is, the technology according to the present disclosure can achieve other effects apparent to those skilled in the art from the description of the present specification together with the above effects or instead of the above effects. 
     Additionally, the following configurations also belong to the technical scope of the present disclosure. 
     (1) 
     A communication apparatus including: 
     a plurality of antenna parts configured to receive or transmit a wireless signal; 
     a communication control part configured to control transmitting or receiving the wireless signal via at least any of the plurality of antenna parts; and 
     a casing housing the communication control part, 
     in which each of the plurality of antenna parts is held near each of a plurality of partial regions normal directions of which cross each other or the normal directions of which are mutually twisted in outer faces of the casing, and transmit or receive a first wireless signal and a second wireless signal propagating in directions substantially orthogonal to the partial regions and having mutually different polarization directions. 
     (2) 
     The communication apparatus according to (1), in which the antenna part includes an antenna device configured to transmit or receive the first wireless signal and the second wireless signal the polarization directions of which are orthogonal to each other. 
     (3) 
     The communication apparatus according to (2), in which the antenna device is configured as a planar antenna. 
     (4) 
     The communication apparatus according to (2) or (3), in which the antenna part includes a plurality of the antenna devices. 
     (5) 
     The communication apparatus according to (1), 
     in which the antenna part includes: 
     a first antenna device configured to receive or transmit the first wireless signal; and 
     a second antenna device configured to receive or transmit the second wireless signal. 
     (6) 
     The communication apparatus according to (5), in which at least any of the first antenna device and the second antenna device is configured as any of a monopole antenna, a dipole antenna, a one-side short-circuit planar antenna, a notch antenna, an inverted F-antenna, a loop antenna, and a slot antenna. 
     (7) 
     The communication apparatus according to (5) or (6), in which the antenna part includes at least any of a plurality of the first antenna devices or the second antenna devices. 
     (8) 
     The communication apparatus according to (1), 
     in which the antenna parts are held along a plurality of the outer faces the normal directions of which cross each other or the normal directions of which are mutually twisted and are continuous, and 
     include an antenna device configured to transmit or receive the first wireless signal and the second wireless signal propagating in a direction substantially orthogonal to the partial region of the outer face for each of the plurality of outer faces. 
     (9) 
     The communication apparatus according to any one of (1) to (8), in which the communication control part controls receiving the first wireless signal and the second wireless signal arriving in the normal direction of a second partial region different from a first partial region gripped by a user by the antenna part held near the second partial region in the outer faces of the casing. 
     (10) 
     The communication apparatus according to any one of (1) to (9), 
     in which at least one face of the outer faces of the casing forms a rectangular shape, and 
     at least some antenna parts in the plurality of antenna parts are held near the partial regions of at least some of end faces positioned around the face. 
     (01) 
     The communication apparatus according to (10), in which at least some antenna parts in the plurality of antenna parts are held near the partial regions of at least some of the end faces positioned on an upper side in a case where the casing is gripped such that a longitudinal direction of the face is a vertical direction. 
     (12) 
     The communication apparatus according to (10) or (11), in which at least some antenna parts in the plurality of antenna pans are held near the partial regions of at least some of the end faces positioned on the upper side in a case where the casing is gripped such that the vertical direction of the casing substantially matches with a vertical direction of a user facing the face of the casing. 
     (13) 
     The communication apparatus according to any one of (10) to (12), in which at least some antenna parts in the plurality of antenna parts are held near the partial regions of at least some of faces extending in the longitudinal direction of the face in the end faces. 
     (14) 
     The communication apparatus according to any one of (10) to (13), in which at least some antenna parts in the plurality of antenna parts are held near the partial region of at least part of the face. 
     (15) 
     The communication apparatus according to any one of (10) to (14), 
     in which a display part in a rectangular shape is provided on the face, and 
     at least some antenna parts in the plurality of antenna parts are held near the partial regions of at least some of faces extending along the ends in a longitudinal direction of the display part in the end faces. 
     (16) 
     The communication apparatus according to any one of (1) to (15), in which at least two antenna parts in the plurality of antenna parts are held near a plurality of the partial regions the normal directions of which cross each other or the normal directions of which are mutually twisted in the outer faces at least part of which is curved. 
     REFERENCE SIGNS LIST 
     
         
           1  System 
           100  Base station 
           200  Terminal apparatus 
           2001  Antenna part 
           2003  Wireless communication part 
           2005  Communication control part 
           2007  Storage part 
           209  Casing 
           2111   a  to  2111   f  Antenna apparatus