JP2009055328A - Portable broadband antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a portable broadband antenna capable of achieving high performance with a simple configuration. <P>SOLUTION: A business bag 20 is provided with a central storage space 22a, and is provided with a front cushioning material space 24 and a back cushioning material space 25 for placing cushioning materials at the front of and at the back of the central storage space 22a. A plate-like radiating element 31 constituting a portable broadband antenna 30A is stored together with the cushioning material in the front cushioning material space 24, while a reflecting plate 36 is stored together with the cushioning material in the back cushioning material space 25. One end of a power supply cable 33 is connected to a feed point 32 of the radiating element 31, and the other end of the power supply cable 33 is connected to a connector 34 for output provided at a lower part of a side of the business bag 20. The radiating element 31 and the reflecting plate 36 are stored in the business bag 20 so as to maintain a prescribed interval so that a broadband and a high gain characteristic can be obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a portable broadband antenna used for receiving and communicating terrestrial broadcast waves, for example.

  Terrestrial digital (television) broadcasting (ISDB-T: Integrated Services Digital Broadcasting-Terrestrial) uses radio waves in the UHF band, and the frequency band is 470 to 770 MHz (13 to 62 channels). In addition, mobile phones, terrestrial digital broadcasts, terrestrial digital 1 SEG broadcasts (1 segment broadcasts), etc. are retransmitted in buildings and underground shopping streets. Under such circumstances, the receiving antenna is required to have high gain, wide bandwidth and portability.

  Conventionally, a telescopic rod antenna is generally known as a portable antenna that receives UHF radio waves (see, for example, Patent Document 1).

  The telescopic rod antenna is configured as shown in FIGS. 10 (a) and 10 (b). FIGS. 10A and 10B show the external configuration of the telescopic rod antenna 10, where FIG. 10A is a side view at the time of full reduction, and FIG.

  10 (a) and 10 (b), reference numeral 11 denotes an antenna element, and a plurality of cylindrical pipe conductors 12a to 12n having different diameters are slidably connected to each other so as to expand and contract.

10A is the length when the antenna element 11 is fully reduced, and LB shown in FIG. 10B is the length when the antenna element 11 is fully extended.
Japanese Patent Laid-Open No. 11-239013

  The conventional telescopic rod antenna 10 configured as described above can be formed relatively thin, and the other pipe conductor can be stored in the pipe conductor 12a having the maximum diameter, so that it can be miniaturized and carried. it can.

  However, the conventional telescopic rod antenna 10 has a low gain of about 0 dBi, and requires a plurality of pipe conductors 12a to 12n constituting the antenna element 11, and is configured at a low cost by increasing the number of parts. There was a problem that could not be done.

  Further, the telescopic rod antenna 10 has a relatively narrow band as shown by the VSWR characteristic of FIG. 11 due to the characteristics of the antenna structure. It was necessary to adjust the length. FIG. 11 shows an example of VSWR characteristics when the length of the antenna element 11 is fixed at a predetermined position in the conventional telescopic rod antenna 10.

  In digital terrestrial broadcasting, data is digitized and transmitted, so that it cannot be received at all unless a certain reception level is obtained. For this reason, the conventional antenna having a gain of about 0 dBi often has insufficient gain and cannot receive signals.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a portable broadband antenna capable of improving performance with a simple configuration.

  The portable broadband antenna according to the first invention is provided with a front cushioning material space at the front of the central storage space of the bag formed of an insulating member, and the front cushioning material space has a broadband, high gain plate shape. The radiating element is housed, and an output plug provided on one side of the bag and a feeding point of the radiating element are connected by a feeding cable.

  The portable broadband antenna according to the second invention is provided with a front cushioning material space and a rear cushioning material space before and after the central storage space of the bag formed of an insulating member, and the front cushioning material space has a wideband, high A plate-shaped radiating element with a gain is accommodated, and a plate-shaped reflecting plate is accommodated in the rear cushioning material space, and the gap between the output plug provided on one side of the bag and the feeding point of the radiating element It is characterized by being connected by a power supply cable.

  According to the present invention, a small-sized antenna can be built in a business bag or the like and can be carried around in a building or an underground city, and even when receiving terrestrial digital broadcasting having a wide frequency band, It can be received as it is without adjusting the length or the like. In addition, a constant reception level can be obtained with a high antenna gain, and a stable reception state can be maintained. In addition, by incorporating a radiation element and a reflector using the buffer material space of the bag, the design of the bag itself is not destroyed and an aesthetic sense can be maintained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a perspective view showing a portable broadband antenna according to the first embodiment of the present invention in a business bag, for example, with the front side of the business bag removed, and FIG. 2 is a state in which the business bag shown in FIG. FIG. FIG. 3 is a front view showing a radiating element portion of the portable broadband antenna, FIG. 4 shows a configuration in which the radiating element of the portable broadband antenna and a reflector are combined, (a) is a front view, (b) ) Is a side view.

  1 and 2, reference numeral 20 denotes a bag, for example, a business bag, which is formed in a box shape having a height La of about 300 mm and a width Lb of about 430 mm using an insulating member such as cloth or synthetic resin.

  The business bag 20 is provided with a handle 21 on the upper outer side, a central storage space 22a for storing articles in the center of the interior, a narrow front storage space 22b on the front and rear sides, and a rear storage space 22c. Provided. The central storage space 22a, the front storage space 22b, and the rear storage space 22c can be opened and closed by fasteners 23a to 23c, respectively.

  Before and after the central storage space 22a, that is, between the central storage space 22a and the front storage space 22b, and between the central storage space 22a and the rear storage space 22c, before the buffer material (dielectric) is inserted. A part cushioning material space 24 and a rear part cushioning material space 25 are provided. The front buffer material space 24 is formed by partitioning the front and rear portions thereof with partition members 26a and 26b, and the rear buffer material space 25 is formed by partitioning the front and rear surfaces thereof with partition members 27a and 27b.

  In the front buffer material space 24, a plate-shaped radiating element 31 constituting the portable broadband antenna 30A is stored together with the buffer material, and in the rear buffer material space 25, the reflection plate 36 is stored together with the buffer material. In this case, it is desirable that the radiating element 31 is made of, for example, a film-like metal body or a metal plate of 1 mm or less so as not to be too thick. Details of the shapes and dimensions of the radiating element 31 and the reflector 36 constituting the portable broadband antenna 30A will be described later. The radiating element 31 is provided with a feeding point 32 at the center, and one end of a feeding cable 33 is connected to the feeding point 32. The other end of the power supply cable 33 is connected to an output plug 34 provided, for example, below the side of the business basket 20. The output plug 34 is connected to a TV receiver or the like having a digital terrestrial broadcast reception function via a coaxial cable (not shown).

  Next, the details of the portable broadband antenna 30A composed of the radiating element 31 and the reflecting plate 36 will be described with reference to FIG.

  In the radiating element 31, first and second antenna elements 41a and 41b formed of a plate-like conductive member are arranged at a predetermined interval in the vertical direction in the same plane, and are coupled by a coupling line 42 to be substantially the same. It is formed in a Z shape. The first and second antenna elements 41a and 41b are a linear element 43 having a predetermined width formed on both outer sides in the vertical direction and a predetermined width formed by bending both ends of the linear element 43 by approximately 90 °. It consists of the side element 44, and is provided symmetrically with a gap 47a, 47b at the center. The first antenna element 41a has a shape in which a U-shape is rotated 90 ° counterclockwise, and the second antenna element 41b has a shape in which the U-shape is rotated 90 ° clockwise. ing.

  The coupling line 42 has a shape in which the end portions of the side elements 44 of the first and second antenna elements 41a and 41b are bent at a predetermined angle smaller than 90 °, for example, about 40 ° in the present embodiment. The groove 45 is provided in the vertical direction of the central portion. The width of the coupling line 42 is gradually increased from the side element 44 to the groove 45. In the coupling line 42, feeding protrusions 46a and 46b are formed at the center of the groove 45, and feeding points 32a and 32b are provided at the feeding protrusions 46a and 46b. The power feeding cable 33 shown in FIG. 2 is connected to the power feeding points 32a and 32b.

  As described above, the outer shape of the radiating element 31 is formed such that the outer width W5 of the feeding point portion of the coupling line 42 is narrower than the outer width W1 of the linear element 43, that is, the width between the side elements 44, 44. It is formed so as to be inclined from the vicinity toward the side element 44. That is, with respect to the outer shape of the first antenna element 41a located on the upper side, the upper side of the linear element 43 is the upper side, the outer side of the side element 44 is the side side, and the outer side of the coupled line portion is inclined toward the inner side. And the feeding point in the vertical direction is continuous thereunder. The outer shape of the second antenna element 41b located on the lower side is the same as that of the first antenna element 41a.

  Further, the inner shape of the first antenna element 41a is such that the lateral width W1 ′ of the lower part (inner side) of the linear element 43 is larger than the outer lateral width W5 of the feeding point part or the lateral width Wa of the groove 45, and the feeding point part or its vicinity. Thus, the structure gradually increases in the direction of the linear element 43. In FIG. 4, the structure gradually increases from the upper end of the groove 45 toward the side element 44. In other words, the inner shape of the first antenna element 41a is the lower side of the linear element 43 as the upper side, the inner side of the side element 44 as the side side, and the inner side of the coupled line portion as the oblique side that inclines inward. Are formed so that the vertical grooves 45 are continuous with each other. The inner shape of the second antenna element 41b is symmetrical with the inner shape of the first antenna element 41a.

  The radiating element 31 formed as described above has an overall length L1 of about 0.8λ in the vertical direction and a total width, that is, the length W1 of the linear element 43 constituting the first and second antenna elements 41a and 41b is about 0. .5λ. In the first and second antenna elements 41a and 41b, the element width W2 of the linear element 43 is set to about 0.08λ, and the element width W3 of the side element 44 is set to about 0.1λ. In this case, the element width W3 of the side element 44 is set to a value larger than the width W2 of the linear element 43, for example, about 1 to 1.5 times the element width W2. Further, the left and right central element width W4 of the groove 45 in the coupled line 42 is set to about 0.05λ. For example, λ represents a wavelength of 620 MHz, which is an intermediate frequency (470 to 770 MHz) in terrestrial digital broadcasting.

  Further, the lateral width Wa of the groove 45 is about 0.04λ, and the outer lateral width W5 of the feeding point portion is about 0.14λ.

  The reflecting plate 36 is a metal plate formed in a square shape, and the total length L2 in the vertical direction is set to about 0.85λ, and the total width W6 is set to about 0.6λ. .8λ) and width W1 (about 0.5λ). The reflector 36 may be approximately the same size as the radiating element 31, but is preferably set larger than the radiating element 31. The reflection plate 36 is accommodated in the rear cushioning material space 25 of the business basket 20 as described above, and is disposed opposite to the back surface side of the radiating element 31 with a predetermined distance D1. A distance D1 between the radiating element 31 and the reflecting plate 36 is set to about 0.125λ to about 0.26λ.

  The portable broadband antenna 30A is set to a size that can be stored in the business bag 20.

  When the portable broadband antenna 30A built in the business basket 20 receives vertically polarized radio waves, the business basket 20 is placed horizontally so that the linear element 43 is positioned vertically, and the horizontally polarized radio waves are transmitted. When receiving, the business basket 20 is placed vertically so that the linear element 43 is positioned horizontally.

  As described above, the radiating element 31 is configured by the first and second antenna elements 41a and 41b including the linear element 43 and the side element 44, and the coupling line 42 is formed from the vicinity of the feeding points 32a and 32b to the side portion. The radiating element 31 and the reflection plate 36 are formed by gradually increasing toward the element 44 and setting the element width W3 of the side element 44 to about 1 to 1.5 times the width W2 of the linear element 43. Even if the interval D1 is set to a narrow interval of about 0.125λ, the bandwidth can be increased and the impedance of the feeding point at the feeding points 32a and 32b can be reduced to be maintained at about 75Ω (unbalanced). It is possible to supply power directly to 32b using a 75Ω coaxial cable.

  The feed point impedance can be finely adjusted by, for example, the shape and line width of the coupled line 42. As a result, an impedance conversion transformer is not required, and the number of parts can be reduced to reduce the cost.

  FIG. 5 shows the VSWR characteristics of the portable broadband antenna 30A built in the business basket 20, with the horizontal axis representing frequency (MHz) and the vertical axis representing VSWR (voltage standing wave ratio). In this case, the business bag 20 has a height La of about 300 mm and a width Lb of about 430 mm. 5 represents the VSWR characteristic when the distance D1 between the radiating element 31 and the reflecting plate 36 is set to 0.145λ, and the broken line b represents the VSWR characteristic when the distance D1 between the radiating element 31 and the reflecting plate 36 is set to 0.26λ. Show.

  FIG. 6 shows the gain characteristics of the portable broadband antenna 30A built in the business bag 20, and realizes an antenna gain of about 6 to 7.5 dBi at a frequency (470 to 770 MHz) in terrestrial digital broadcasting. Can do.

  7A shows the vertical polarization vertical plane directivity of the portable broadband antenna 30A built in the business basket 20, and FIG. 7B shows the vertical polarization horizontal plane directivity of the portable broadband antenna 30A. ing. Good unidirectional directivity is obtained in both cases of the vertical polarization vertical plane directivity and the vertical polarization horizontal plane directivity.

  Since the portable broadband antenna 30A according to the above embodiment can be formed in a small size, it can be mounted on a business bag 20 or the like and carried in a building or an underground shopping area, and has a high gain and a wide band. Therefore, 470 to 770 MHz. Even when terrestrial digital broadcasting having a wide frequency band is received, it can be received as it is without adjusting the antenna length or the like. In addition, since the portable broadband antenna according to the above embodiment can achieve an antenna gain of about 6 to 7 dBi, a constant reception level can be obtained even when digital terrestrial broadcasting is received, and a stable reception state is maintained. can do.

  Further, by incorporating the radiating element 31 and the reflector 36 using the front cushioning material space 24 and the rear cushioning material space 25 of the business bag 20, the design of the bag itself is not destroyed and the aesthetic sense is maintained. Can do. Moreover, if a receiving device (tuner) is put in the central storage space 22a of the business bag 20 and carried, it becomes unnecessary to carry another external antenna.

  If there is a large metal object such as a PC (personal computer) in the business bag 20, it may not function as an antenna sufficiently. So you can watch terrestrial digital broadcasts without problems.

  In the first embodiment, the case where the radiating element 31 and the reflecting plate 36 are built in the business bag 20 has been described. However, the reflecting plate 36 may be omitted and only the radiating element 31 may be built in the business bag 20. Since an antenna gain of about 2 dBi can be obtained, terrestrial digital broadcasting can be viewed without problems. Even when the reflector 36 is omitted and the antenna is configured by only the radiating element 31, it is possible to maintain a broadband characteristic substantially equivalent to that when the reflector 36 is used.

(Second Embodiment)
Next, a portable broadband antenna according to a second embodiment of the present invention will be described.

  FIG. 8 is a perspective view of the portable broadband antenna 30B according to the second embodiment of the present invention stored in the business basket 20, and the front side of the business basket 20 is removed. FIG. 9 is a perspective view of the portable broadband antenna 30B. FIG.

  The portable broadband antenna 30 </ b> B is accommodated in the front cushioning material space 24 of the business basket 20 together with the cushioning material. Since the business bag 20 has the same configuration as that shown in the first embodiment, the same parts are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the portable broadband antenna 30B, the upper radiating element 51a and the lower radiating element 51b are configured symmetrically using a conductive member such as a film-like metal body formed in a substantially rectangular shape or a metal plate of 1 mm or less, for example. .

  That is, the portable broadband antenna 30B is provided with a first slit 52 in the horizontal direction at the center of a plate-like conductive member formed in a rectangular shape having a lateral width L11 and a height H, and an upper radiating element 51a and a lower radiating element. 51b is separated. In this case, the first slit 52 is provided in the center leaving the power supply protrusions 53a and 53b, and the power supply points 54a and 54b are formed in the power supply protrusions 53a and 53b. The feeding points 54a and 54b may be provided with only a hole, for example, or may be provided with a feeding terminal in this hole.

  The upper radiating element 51a and the lower radiating element 51b are vertically provided with a second slit 55 in the central portion from the vicinity of the upper side to the vicinity of the lower side, and plate-shaped dipole elements 56a and 56b are formed on the left and right, respectively. The The upper radiating element 51a and the lower radiating element 51b are provided with a third slit 57 having a length L12 in the vicinity of the upper side and in the vicinity of the lower side to form a folding element 58.

  In the portable broadband antenna 30B, for example, the lateral width L11 is set to about 0.46λ, the height H is set to about 0.33λ, and the width D11 of the second slit 55 and the width D12 of the third slit 57 are set to about 0.013λ. Is done. The length L12 of the third slit 57 is set to about 0.39λ.

  In the portable broadband antenna 30B, one end of the power supply cable 33 is connected to the power supply points 54a and 54b, and the other end of the power supply cable 33 is connected to the output plug 34 provided below the side of the business bag 20. Connected.

  When the portable broadband antenna 30B configured as described above is fed from the output plug 34 to the feeding points 54a and 54b of the dipole elements 56a and 56b, the upper radiating element 51a and the lower radiating element are fed from the feeding points 54a and 54b. The feeding current flows along the periphery of the dipole elements 56a and 56b in the element 51b, and the same operation as the two-wire folded dipole is performed. As a result, the portable broadband antenna 30B exhibits the same effect as the two-wire folded dipole antenna, can achieve a wide band and correct the impedance, and can realize a good VSWR characteristic while achieving a reduction in size. An antenna gain of about 2 dBi can be obtained.

  The portable broadband antenna 30B according to the second embodiment can be formed more compact than the portable broadband antenna 30A shown in the first embodiment, and can be mounted on a business bag 20 or the like to be installed in a building or an underground mall. Can carry around. In addition, the portable broadband antenna 30B can have broadband characteristics like the portable broadband antenna 30A according to the first embodiment, and even when receiving terrestrial digital broadcasting having a wide frequency band, It can be received as it is without adjusting the length or the like. In addition, since the portable broadband antenna 30B does not use a reflector, the directivity thereof is an 8-shaped directional characteristic and can receive radio waves from the front and rear of the antenna.

  Although the portable broadband antenna 30B according to the second embodiment has been described with respect to the case where the reflector is omitted, a reflector is provided in the rear cushioning material space 25 of the business basket 20 as in the first embodiment. It may be stored. Thus, the antenna gain can be improved to about 6 to 7 dBi by using the reflector.

  Further, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage.

FIG. 2 is a perspective view showing the portable broadband antenna according to the first embodiment of the present invention stored in a business bag and with the front surface of the business bag removed. It is a sectional side view which shows the state which made the business bag shown in FIG. 1 vertical. It is a front view which shows the radiation | emission element part of the portable wideband antenna which concerns on the same embodiment. The structure which combined the radiation | emission element and reflector of the portable wideband antenna which concern on the embodiment is shown, (a) is a front view, (b) is a side view. It is a VSWR characteristic view of the portable broadband antenna according to the embodiment. It is a gain characteristic figure of the portable broadband antenna concerning the embodiment. (A) is a figure which shows the vertical polarization vertical plane directivity of the portable wideband antenna which concerns on the embodiment, (b) is a figure which shows the vertical polarization horizontal plane directivity of the portable wideband antenna. FIG. 6 is a perspective view showing a portable broadband antenna according to a second embodiment of the present invention housed in a business bag and with the front surface of the business bag removed. It is a front view which takes out from the business bag and shows the portable wideband antenna which concerns on the embodiment. The external appearance structure of the conventional expansion-contraction type rod antenna is shown, (a) is a side view at the time of full reduction, (b) is a side view at the time of full extension. It is a VSWR characteristic view of a conventional telescopic rod antenna.

Explanation of symbols

  20 ... Business bag, 21 ... Handle, 22a ... Central storage space, 22b ... Front storage space, 22c ... Rear storage space, 23a-23c ... Fastener, 24 ... Front shock absorber space, 25 ... Rear shock absorber space, 26a , 26b, 27a, 27b ... partitioning material, 28 ... glove compartment, 30A ... portable broadband antenna according to the first embodiment, 30B ... portable broadband antenna according to the second embodiment, 31 ... radiating element, 32, 32a, 32b ... feed point, 33 ... feed cable, 34 ... output plug, 36 ... reflector, 41a ... first antenna element, 41b ... second antenna element, 42 ... coupled line, 43 ... linear element, 44 ... side element, 45 ... groove, 46a, 46b ... feeding projection, 47a, 47b ... gap, 51a ... upper radiating element, 51b ... lower radiating element, 52 ... first slot DOO, 53a, 53b ... feeding projections, 54a, 54b ... feeding point, 55 ... second slit, 56a, 56b ... dipole elements, 57 ... third slit, 58 ... folded element.

Claims (2)

  A front cushioning material space is provided in front of the central storage space of the bag formed by the insulating member, and a broadband, high-gain plate-like radiating element is stored in the front buffering material space. A portable broadband antenna characterized in that an output plug provided in a section and a feeding point of the radiating element are connected by a feeding cable   A front buffer material space and a rear buffer material space are provided before and after the central storage space of the bag formed by the insulating member, and a broadband, high-gain plate-shaped radiation element is stored in the front buffer material space and A portable type characterized in that a plate-like reflecting plate is accommodated in a rear cushioning material space, and an output plug provided on one side of the bag and a feeding point of the radiating element are connected by a feeding cable. Broadband antenna.

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