Patent Publication Number: US-6664928-B2

Title: Antenna apparatus for performing wireless communication or broadcasting by selecting one of two types of linearly polarized waves

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2001-258400, filed Aug. 28, 2001; and No. 2002-068140, filed Mar. 13, 2002, the entire contents of both of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an antenna apparatus which is installed, e.g., outdoors and is used for performing wireless transmission of voice or data to a base station connected to a basic network. 
     2. Description of the Related Art 
     In recent wireless system, data transmission service referred to as, e.g., WLL (Wireless Local Loop) or FWA (Fixed Wireless Access) is proposed. In such services, an antenna apparatus is installed outdoors, and wireless communication or broadcasting via the antenna apparatus to a base station connected to a basic network is performed. 
     In such services, a horizontally (H) polarization or a vertically (V) polarization is used depending on types of data to be transmitted, purposes of its use, or environment. An antenna, which is selected depending on whether radio wave used for the communication or broadcasting, is a horizontally polarized wave or a vertically polarized wave, is provided as the antenna apparatus used for the service. 
     However, in the above-described antenna apparatus, two different types of polarizations must be performed in order to a desired communication network or a broadcasting network. Then, the antenna apparatus which handles the polarized waves used for the desired communication or broadcasting network is selected and installed at a desired location to construct the communication or broadcasting network. Consequently, there arise the problems that the ordering of the antenna apparatus, manufacturing thereof and inventory management thereof are complicated and troublesome. 
     BRIEF SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an antenna apparatus which has simple configuration and enables wireless communication or broadcasting using two types of linearly polarized waves in order to simplify handling properties including its order, manufacturing process thereof and inventory management thereof. 
     The antenna apparatus of the present invention comprises an antenna main body for linearly polarized which is accommodated in a case in a direction of vertically polarized wave or in a direction of horizontally polarized wave, both of directions being perpendicular to each other; and a heat sink which is disposed at a rear surface of the case and thermally coupled to the antenna main body to thermally control the antenna main body. 
     In accordance with this configuration, the antenna main body is accommodated in a case in a direction of vertically polarized wave or in a direction of horizontally polarized wave. As a result, the present invention can be configured as to as correspond to both of wireless communication or broadcasting using the vertically and wireless communication or broadcasting using the horizontally polarized wave. 
     It is possible to simply and easily set such that the wireless communication or broadcasting using the vertically polarized wave or the horizontally polarized wave can be performed merely by an operation for changing the direction in which the antenna main body is accommodated in the case. Therefore, simplification of handling properties including order for the antenna apparatus, a manufacturing process thereof and inventory management thereof can be realized and diversification of communication or broadcasting can be accomplished. 
     Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
     FIG. 1 is an exploded perspective view of an antenna apparatus according to one embodiment of the present invention in which a main portion thereof is exploded and shown. 
     FIG. 2 is an exploded perspective view seen from the front, showing an exploded state shown in FIG.  1 . 
     FIG. 3 is a perspective view showing a state in which radiating fins of a heat sink shown in FIG. 1 are arranged in a direction of vertically polarized wave. 
     FIG. 4 is a perspective view showing a state in which the radiating fins of the heat sink shown in FIG. 1 are arranged in a direction of horizontally polarized wave. 
     FIG. 5 is a perspective view seen from the back, showing a state in which a case shown in FIG. 1 is mounted to a support. 
     FIG. 6 is a perspective view seen from the front, showing the state in which the case shown in FIG. 1 is mounted to the support. 
     FIG. 7 is a perspective view showing configuration of a heat sink of an antenna apparatus according to another embodiment of the present invention. 
     FIG. 8 is a plan view, as seen from the back, of the configuration shown in FIG.  7 . 
     FIG. 9 is a plan view of configuration of a heat sink of an antenna apparatus according to yet another embodiment of the present invention. 
     FIG. 10 is a perspective view showing configuration of arrangement of an external connector of an antenna apparatus according to yet another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of the present invention will be described hereinafter with reference to the drawings. 
     FIGS. 1 and 2 show respectively an antenna apparatus according to one embodiment of the present invention. FIG. 1 shows a state, as seen from the back, in which a case  10  which configures an antenna main body, an antenna  11  for linearly polarized wave and a radome  12  made of resin material are exploded. FIG. 2 shows such state seen from the front. 
     The case  10  is made of metallic material such as aluminum or the like and has a substantially concave accommodating portion  101  provided at its one surface. A high-frequency circuit portion  13  is accommodated in the accommodating portion  101  of the case  10 . The antenna  11  is placed on the high-frequency circuit portion  13 . The radome  12  is attached to a front surface of the high-frequency circuit portion  13  so as to cover the antenna  11 . Thus, the high-frequency circuit portion  13  and the antenna  11  are hermetically accommodated within the case  10  and the radome  12 . 
     As shown in FIG. 3, the antenna  11  which is hermetically accommodated within the case  10  and the radome  12  is set so as to be possible to perform communication or broadcasting using vertically (V) polarization in a state in which a plane of polarization governed by the antenna is vertical to the ground. When the case  10  is rotated about 90° from the position of the vertically polarized wave, the plane of polarization governed by the antenna  11  is, as shown in FIG. 4, switched such that wireless communication or broadcasting using a horizontally (H) polarization can be performed. 
     A radiating heat sink  14  is disposed at the rear surface of the case  10 . The heat sink  14  is disposed so as to form a predetermined tilt angle such that radiating fins  141  are disposed so as to form an acute angle of about 45° with respect to, e.g., a direction of gravity in any one of the state of the vertically polarized wave and the state of the horizontally polarized wave. The heat sink  14  is thermally coupled via the case  10  to the high-frequency circuit portion  13  within the accommodating portion  101  of the case  10 . Thus, even if the case  10  is rotated 90° such that the antenna  11  is set to either of the direction of the vertically polarized wave and the direction of the horizontal polarized wave, the heat sink  14  takes two substantially symmetrical positions where radiating fins  141  are tilted about 45° with respect to the direction of gravity, while being thermally coupled to the high-frequency circuit portion  13 . 
     When heat is transmitted from the high-frequency circuit portion  13  to the heat sink  14  in the above-described two positions, the heat sink  14  irradiates heat by a chimney effect. Namely, in the chimney effect, air is thermally expanded between the radiating fins  141  such that a specific weight of the air becomes light and updraft occurs. A thermal conductivity of the radiating fins  141  is increased by an effect of flow rate of the updraft. The heat generated at the high-frequency circuit portion  13  is subjected to a so-called natural air cooling by the radiation such that the high-frequency circuit portion  13  is thermally controlled so as to have a predetermined temperature. 
     An external connector  15  which has, for example, water proofing property and is electrically connected to the high-frequency circuit portion  13  is provided at the rear surface of the case  10  so as to protrude in a direction in which the radiating fins  141  of the heat sink  14  are arranged. An exterior data modulator/demodulator (not shown) which is disposed, for example, indoors is electrically connected via a cable  16  to the external connector  15 . The external connector  15  enables electric connection of the external data modulator/demodulator (not shown) with the high-frequency circuit portion  13  within the case  10 . 
     A plurality of mounting protrusions  102  is provided at the rear surface of the case  10  at predetermined intervals therebetween. As shown in FIGS. 5 and 6, a mounting portion  171  of a mounting band  17  is detachably mounted to these mounting protrusions  102  by using unillustrated screw members or the like. The mounting band  17  is mounted to the mounting protrusions  102  of the case  10  by using the above-mentioned screw members (not shown) in any one of the two positions where the mounting portion  171  is rotated 90° depending on whether the polarized wave governed by the antenna  11  is a vertically polarized wave or a horizontally polarized wave. 
     The mounting band  17  is mounted by a band portion  172  being wound around a support  18  for installation in a state in which the mounting portion  171  is mounted to the mounting protrusions  102  of the case  10 . Thus, the antenna  11  is installed at a desired position where communication or broadcasting is possible with the place of polarization being faced in a direction of vertically polarized wave or a direction of horizontally polarized wave. When the antenna  11  is mounted to the support  18 , the position of the mounting band  17  is adjusted such that orientation of the antenna  11  coincides a desired direction of communication or broadcasting. 
     In the above-described configuration, when a radio wave used for communication or broadcasting is a vertically polarized wave, the mounting portion  171  of the mounting band  17  is mounted to the mounting protrusions  102  of the case  10  and the band portion  172  is mounted to the support  18  by taking a plane of polarization governed by the antenna  11  into consideration. At this time, the orientation of the antenna  11  within the case  10  is adjusted for a desired direction of communication or broadcasting. Here, the external connector  15  is protruded downward so as to form a tilt angle of about 45° with respect to the case  10 . The external data modulator/demodulator (not shown) is electrically connected via the cable  16  to the external connector  15 . 
     The antenna  11  receives the vertically polarized and outputs it to the high-frequency circuit portion  13 . The high-frequency circuit portion  13  processes inputted high-frequency signal and directs the resulting signal via the external connector  15  and the cable  16  to the external data modulator/demodulator (not shown). Then, the high-frequency signal sent from the external data modulator/demodulator (not shown) is supplied via the cable  16  and the external connector  15  to the high-frequency circuit portion  13 . At the high-frequency circuit portion  13  the signal is processed, and then is outputted to the antenna  11  which governs the vertically polarized wave. The resulting signal is sent by the antenna  11  in a desired orientation such that communication or broadcasting is performed. 
     In the position where communication or broadcasting using the vertically polarized wave is performed, the heat sink  14  within the case  10  is set such that radiating fins  141  are arranged so as to form a tilt angle of about 45° with respect to the direction of gravity and a desired chimney effect is obtained. Thus, the heat sink  14  performs thermal control by effectively and naturally cooling heat quantity generated by drive of high-frequency circuit portion  13 . 
     When switching to a state in which communication or broadcasting using the horizontally polarized wave is possible is performed, the position for mounting the mounting portion  171  of the mounting band  17  to the mounting protrusions  102  of the case  10  is rotated about 90° and the band portion  172  is mounted to the support  18  such that the position of the mounting band  17  is adjusted so as to coincide the direction of communication or broadcasting. Consequently, the antenna  11  is set so as to be possible to perform transmission/receiving of the horizontally polarized wave. 
     The external connector  15  of the case  10  is protruded downward at the position (where a tilt angle of about 45° is formed) which is rotated about 90° from the position where the communication or broadcasting using the vertically polarized wave is performed. The external data modulator/demodulator is electrically connected via the cable  16  to the external connector  15 . 
     The antenna  11  receives a horizontally polarized wave and outputs it to the high-frequency circuit portion  13 . The high-frequency circuit portion  13  processes inputted high-frequency signal and directs the resulting signal via the external connector  15  and the cable  16  to the external data modulator/demodulator (not shown). The high-frequency signal sent from the external data modulator/demodulator (not shown) is supplied via the cable  16  and the external connector  15  to the high-frequency circuit portion  13 . Subsequent to the signal being processed at the high-frequency circuit portion  13 , the resulting signal is outputted to the antenna  11  which governs the horizontally polarized wave. Then, the signal is sent by the antenna  11  in a desired orientation such that communication or broadcasting is performed. 
     In the position where the communication or broadcasting using the horizontally polarized wave is performed, the heat sink  14  within the case  10  is set such that the radiating fins  141  are arranged so as to form a tilt angle of about 45° at the position which is rotated about 90° from the position in which the communication or broadcasting using the vertically polarized wave is performed and a desired chimney effect is obtained. Thus, the heat sink  14  exhibits the same chimney effect as in the state of performing the above-described communication or broadcasting using the vertically polarized wave, and performs thermal control by effectively and naturally cooling heat quantity generated by drive of the high-frequency circuit portion  13 . 
     As described above, the antenna apparatus accommodates the antenna  11  for linearly polarized wave together with the high-frequency circuit portion  13  within the case  10  in which the heat sink  14  is provided. By rotating the case  10  90° depending on whether the vertically polarized wave is used or the horizontally polarized wave is used, communication or broadcasting using the vertically polarized wave or the horizontally polarized wave is realized with high precision. 
     It is possible to simply and easily set such that the communication or broadcasting using the vertically polarized wave or the horizontally polarized wave can be performed merely by changing the direction in which the same case  10  is installed to the support  18 . Therefore, simplification of handling properties including order for the antenna apparatus, a manufacturing process thereof and inventory management thereof can be realized and diversification of communication or broadcasting can be accomplished. 
     The heat sink  14  is disposed at the case  10  such that the radiating fins  141  are tilted so as to form an acute angle with respect to the direction of gravity in both a case of using the vertically polarized wave as a wave governed by the antenna  11  and a case of using the horizontally polarized wave as a wave governed by the antenna  11 . 
     The heat sink  14  can exhibit substantially same chimney effect in both of the position of the vertically polarized wave governed by the antenna  11  and the position of the horizontally polarized wave governed by the antenna  11 . Thus, thermal control of the high-frequency circuit portion  13  can be realized with high efficiency. 
     In the above-described embodiment, a case where the radiating fins  141  of the heat sink  14  are arranged at the rear surface of the case  10  so as to form a tilt angle of about 45° with respect to the direction of gravity in both cases of using the vertically polarized wave governed by the antenna  11  and of using the horizontally polarized wave governed by the antenna  11  has been described. However, the present invention is not limited to this angle at which the fins are arranged, and fins may be arranged at other acute angle and the substantially same effect can be expected. 
     In the above embodiment, the case in which the antenna apparatus is configured by using the heat sink  14  in which the radiating fins  141  are arranged so as to form an acute angle with respect to the direction of gravity has been described. However, the present invention is not limited to this case, and configurations such as those shown in FIGS. 7,  8  and  9  may be utilized. In FIGS. 7 through 9, for convenience, the same portions as those of FIGS. 1 through 6 are denoted by the same reference numerals and descriptions thereof are omitted. 
     A heat sink  19  shown in FIGS. 7 and 8 is formed such that a plurality of radiating fins  191  which are bent about 90° are radially combined and arranged in two directions which are perpendicular to each other. The heat sink  19  is disposed at the rear surface of the case  10 . Radiation configuration which effectively utilizes a radiation efficiency of radiating fins  191  depending on the direction that the antenna  11  is arranged is configured. Thus, substantially same radiation efficiency as those of the above-described embodiments can be ensured in both of the case of the vertically polarized wave and the case of the horizontally polarized wave. As a result, substantially same effect as those of the above-described embodiments can be expected. 
     A heat sink  21  shown in FIG. 9 is configured such that a plurality of curved radiating fins  211  are concentrically arranged. The heat sink  21  is disposed at the rear surface of the case  10 . In the heat sink  21 , radiation configuration which effectively utilizes a radiation efficiency of the radiating fins  211  depending on the direction that the antenna  11  is arranged is configured. Substantially same radiation efficiency as those of the above-described embodiments can be ensured in both of the case of the vertically polarized wave and the case of the horizontally polarized wave. As a result, substantially same effect as those of the above-described embodiments can be expected. 
     In the above-described embodiments, the configuration in which the radiating fins  211  of the heat sink  21  are concentrically arranged is shown. However, the present invention is not limited to this configuration, and the radiating fins  211  may be arranged substantially circularly. 
     Further, in the above-described embodiments, the case in which the external connector  15  is provided so as to protrude to make an acute angle with respect to the direction of gravity in both of the case of using the vertically polarized wave and the case of using the horizontally polarized wave has been described. However, the present invention is not limited to this case. For example, the external connector  151  may be disposed as shown in FIG.  10 . In FIG. 10, for convenience, the same portions as those of FIGS. 1 through 6 are denoted by the same reference numerals, and descriptions thereof will be omitted. 
     In an embodiment shown in FIG. 10, the external connector  151  is provided at the rear surface of the case  10  so as to protrude substantially parallel to a direction that the radiating fins  141  are protruded. In this embodiment, as the above-described embodiments, stable connection to the external modulator/demodulator (not shown) can be realized in both of the case that the vertically polarized wave is governed by the case  10  and the case that horizontally polarized wave is governed by the case  10 . Further, substantially same effect as those of the above-described embodiments can be expected. 
     The external connector  151  shown in FIG. 10 which is provided so as to protrude substantially parallel to the direction that the radiating fins  141  are protruded may be applied to the heat sink configurations including the heat sink  19  shown in FIGS. 7 and 8 and the heat sink  21  shown in FIG.  9 . The same effect as those of heat sink configurations shown in FIGS. 7,  8  and  9  can be expected. 
     In the above-described embodiments, the case in which the present invention is applied to the antenna configuration that the antenna  11  is hermetically accommodated in the case  10  and the radome  12 . However, the present invention is not limited to this antenna configuration, and other antenna configurations may be utilized. The same effect as those of the above-described embodiments can be expected. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.