WO2010116570A1 - Antenna device - Google Patents

Antenna device Download PDF

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Publication number
WO2010116570A1
WO2010116570A1 PCT/JP2009/070780 JP2009070780W WO2010116570A1 WO 2010116570 A1 WO2010116570 A1 WO 2010116570A1 JP 2009070780 W JP2009070780 W JP 2009070780W WO 2010116570 A1 WO2010116570 A1 WO 2010116570A1
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WO
WIPO (PCT)
Prior art keywords
reflector
antenna
antenna device
folded
elements
Prior art date
Application number
PCT/JP2009/070780
Other languages
French (fr)
Japanese (ja)
Inventor
健 田中
伊市 若生
Original Assignee
株式会社 日立国際電気
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2009093266A external-priority patent/JP2010245892A/en
Priority claimed from JP2009278824A external-priority patent/JP2011124653A/en
Application filed by 株式会社 日立国際電気 filed Critical 株式会社 日立国際電気
Publication of WO2010116570A1 publication Critical patent/WO2010116570A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/10—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces
    • H01Q19/108—Combination of a dipole with a plane reflecting surface
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/10—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces
    • H01Q19/106—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces using two or more intersecting plane surfaces, e.g. corner reflector antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
    • H01Q21/061—Two dimensional planar arrays
    • H01Q21/062—Two dimensional planar arrays using dipole aerials

Definitions

  • the present invention relates to an antenna device used for a communication base station, broadcast transmission, or the like.
  • the present invention has been made paying attention to the above circumstances, and it is an object of the present invention to provide an antenna device that can reduce the antenna shape and maintain directivity and broadband characteristics.
  • One aspect of the present invention is a reflector that is formed in a substantially square shape, an antenna element that is provided on the front surface of the reflector with a predetermined interval, and two bent portions that are provided on both sides of the reflector. And the bent part is coupled to the reflector at a plurality of locations, and a vertical element of a rod-like conductor provided behind the side part in the same direction as the polarization direction of the antenna element.
  • An antenna device having a horizontal element and formed in a frame shape is provided.
  • each of the folded dipole antennas includes a pair of feeding-side elements like a dipole antenna and a substantially ⁇ / 2 ( ⁇ is a wavelength at an operating frequency) that linearly connects both ends of the pair of feeding-side elements.
  • the folding element is formed by extruding a groove-shaped cross section, facing the pair of power feeding elements on the outside of the bottom of the groove, and the width of the groove is A pair of feed-side elements
  • the antenna device is characterized in that the maximum distance of the folded element from the reflector is 0.1 ⁇ or less.
  • an antenna device capable of reducing the antenna shape and maintaining the directivity and the broadband property.
  • FIG. 1 is a perspective view showing a configuration of an antenna with a bent reflector according to a first embodiment of the present invention.
  • FIG. 2 is a side view of the antenna according to the first embodiment.
  • FIG. 3A is a diagram illustrating vertical plane directivity in the specific band of about 40% of the antenna of the first embodiment.
  • FIG. 3B is a diagram illustrating the horizontal plane directivity in the specific band of about 40% of the antenna of the first embodiment.
  • FIG. 4A is a diagram illustrating the vertical plane directivity in the specific band of about 15% of the antenna of the first embodiment.
  • FIG. 4B is a diagram illustrating the horizontal plane directivity in the specific band of about 15% of the antenna of the first embodiment.
  • FIG. 5A is a diagram illustrating the vertical plane directivity in the specific band of about 40% of the antenna of the second embodiment.
  • FIG. 5B is a diagram illustrating horizontal plane directivity in the specific band of about 40% of the antenna of the second embodiment.
  • FIG. 6 is a perspective view illustrating a configuration example when the antenna with a reflector according to the third embodiment of the present invention is multistaged.
  • FIG. 7 is a perspective view showing the configuration of the antenna with a bent reflector of Conventional Example 1.
  • FIG. 8A is a diagram showing the directivity of the vertical plane in the specific band of about 40% of the antenna of Conventional Example 1.
  • FIG. 8B is a diagram illustrating horizontal plane directivity in the specific band of about 40% of the antenna of Conventional Example 1.
  • FIG. 9 is a perspective view showing a configuration of an antenna with a reflector without a bent portion in Conventional Example 2.
  • FIG. 10A is a diagram illustrating the directivity of the vertical plane in the specific band of about 40% of the antenna of Conventional Example 2.
  • FIG. 10B is a diagram illustrating horizontal plane directivity of the antenna of Conventional Example 2 in a specific band of about 40%.
  • FIG. 11 is a three-view diagram illustrating the configuration of the antenna device according to the fourth embodiment of the present invention.
  • 12 is a perspective view of the antenna device of FIG.
  • FIG. 13 is a perspective view of the radiating element 12-2 of the antenna apparatus of FIG.
  • FIG. 14 is a diagram showing the VSWR characteristics of the antenna device of FIG. FIG.
  • FIG. 15 is a diagram illustrating the directivity of the vertical plane of the antenna device of FIG.
  • FIG. 16 is a diagram illustrating the horizontal plane directivity of the antenna device of FIG. 11.
  • FIG. 17 is a diagram illustrating impedance characteristics of the antenna device of FIG.
  • FIG. 18 is a trihedral view of the antenna device according to the fifth embodiment.
  • FIG. 19 is a three-plane view of the feed line 17 of the antenna device of FIG.
  • FIG. 20 is a diagram illustrating the configuration of the antenna device according to the sixth embodiment of the present invention.
  • FIG. 21 is a diagram illustrating the VSWR characteristics of the antenna device according to the sixth embodiment.
  • FIG. 22 is a diagram illustrating the directivity of the vertical plane of the antenna device according to the sixth embodiment.
  • FIG. 23 is a diagram illustrating the horizontal plane directivity of the antenna device according to the sixth embodiment.
  • FIG. 24 is a diagram illustrating impedance characteristics of the antenna device according to the sixth embodiment.
  • FIG. 25 is a diagram illustrating the configuration of the antenna device according to the seventh embodiment of the present invention.
  • FIG. 26 is a diagram illustrating the configuration of the antenna device of the third conventional example.
  • FIG. 27 is a diagram illustrating the VSWR characteristics of the antenna device of Conventional Example 3.
  • FIG. 28 is a diagram illustrating the directivity on the vertical plane of the antenna device of Conventional Example 3.
  • FIG. 29 is a diagram illustrating the horizontal plane directivity of the antenna device of Conventional Example 3.
  • FIG. 30 is a diagram illustrating impedance characteristics of the antenna device according to Conventional Example 3.
  • FIG. 31 is a diagram illustrating a configuration of an antenna device of Conventional Example 4.
  • FIG. 32 is a diagram showing the VSWR characteristics of the antenna device of Conventional Example 4.
  • FIG. 33 is a diagram showing the vertical plane directivity of the antenna device of Conventional Example 4.
  • FIG. 34 is a diagram illustrating the horizontal plane directivity of the antenna device of Conventional Example 4.
  • FIG. 35 is a diagram illustrating impedance characteristics of the antenna device of the conventional example 4.
  • FIG. 1 is a perspective view showing a configuration of an antenna 20 with a bent reflector according to the first embodiment
  • FIG. 2 is a side view of the antenna 20 with the bent reflector.
  • the coordinate system used in FIG. 1 is a right-handed system, where the X-axis direction is the front surface and the Z-axis direction is vertical (that is, the vertical height direction).
  • reference numeral 21 denotes a flat reflecting plate formed in a substantially square shape using a metal plate, and is provided on the YZ plane so that its longitudinal direction is parallel to the Z axis. And it fixes to bending part 22a, 22b in the both sides of a long side, respectively.
  • These bent portions 22 are formed in a frame shape using a rod-shaped conductor, for example, a narrow-width rod-shaped metal plate, and vertical elements 23 respectively provided in parallel to and behind the two long sides of the reflecting plate 21;
  • the vertical element 23 is composed of a horizontal element 24 that couples the reflector to the reflector at two locations, and a vertical element 23 provided between the horizontal elements 24.
  • the horizontal element 24 is provided in the X-axis direction from both ends of the vertical element 23, and its length (the bent width of the bent portion 22a (the length of the horizontal element 24)). Is set to the same value as the vertical width B of the reflecting plate 21.
  • the bent portion 22a has a U-shaped frame as a whole.
  • the horizontal elements 24 are attached to the corners of the four corners of the reflector 21 by, for example, screwing.
  • the antenna element 25 is provided at a central portion on the front side of the reflector 21 with a predetermined interval H by an insulating support member.
  • the antenna element 25 is a dipole antenna element in which, for example, two plate-like elements 26a and 26b are linearly arranged in the longitudinal direction (vertical direction) of the reflecting plate 21, and the central portion thereof, that is, the plate-like element 26a, A power feeding section 27 is provided at the end on the near side of 26b.
  • the antenna with a reflector 20 has a main beam in the substantially X-axis direction of vertical polarization, and the direction of the main beam is referred to as the front surface.
  • the vertical element 23 is provided in the polarization direction.
  • FIG. 3A shows the vertical plane directivity
  • FIG. 3B shows the horizontal plane directivity when the interval H, the width c1 of the vertical element 23 of the bent portion 22a, and the width c2 of the horizontal element 24 are set as follows, for example. .
  • the ratio band (f L to f H ) at this time is about 40%.
  • FIG. 4A shows the antenna 20 with a bent reflector having a specific band of about 15%, that is, “f L : 0.925 ⁇ f C ”, “f C : 1.0 ⁇ f C ”, “f H : 1.075 ⁇ f C ”, and FIG. 4B shows the horizontal plane directivity.
  • FIG. 7 is a perspective view illustrating a configuration of a conventional antenna 10 with a bent reflector in which a bent portion is provided on a side portion of the reflector of the first conventional example.
  • reference numeral 11 denotes a reflecting plate configured using a metal plate, and includes flat plate-like bent portions 12 a and 12 b that are bent rearward (in a direction opposite to the main beam) on both sides.
  • An antenna element 13 is provided at a central portion on the front side of the reflection plate 11 with a predetermined interval H maintained.
  • This antenna element 13 is a dipole antenna element formed by arranging two plate-like elements 14a and 14b in a straight line, and a feeding portion 15 is provided at the center thereof, that is, the adjacent end of the plate-like elements 14a and 14b. .
  • the horizontal width A and vertical width B of the reflector 11, the bending width C of the bent portions 12 a and 12 b, the antenna element length D, the antenna element width d, and the value of the distance H between the reflector 11 and the antenna element 13 are as described above.
  • the setting is the same as in the first embodiment.
  • FIG. 8A shows the vertical plane directivity of the antenna 10 with the bent reflector whose dimensions are set to the above values
  • FIG. 8B shows the horizontal plane directivity of the antenna.
  • the solid line is the characteristic at the center frequency f C (186 MHz) of the communication frequency band
  • the front-to-back ratio (FB ratio) in the antenna 10 with the bent reflector is about “ ⁇ 16 dB” at the lowest frequency f L in the ⁇ 180 degree direction, and at the center frequency f C and the highest frequency f H. About “ ⁇ 18 dB”.
  • the ratio band (f L to f H ) at this time is about 40%.
  • FIG. 9 shows a configuration example of a reflector-equipped antenna 10A as the conventional example 2 when the bent portions 12a and 12b are not provided in the antenna 10 with a folded reflector.
  • the dimensions of each part of the antenna 10A with a reflector without a bent part are the same as those of the antenna 10 with a reflector.
  • FIG. 10A shows a vertical plane directivity and FIG. 10B shows a horizontal plane directivity in a specific band of about 40% of the antenna 10A with a reflector without the bent portion.
  • the solid line is the characteristic at the center frequency f C (186 MHz) of the communication frequency band
  • the broken line is the communication.
  • the reflector-equipped antenna 10A without the bent portion has a directivity half-width of approximately the same as the antenna 10 with the folded reflector shown in FIG. 7, but the front-back ratio in the ⁇ 180 degree direction is about “ ⁇ 15 dB ", which is deteriorated compared to the antenna 10 with the bent reflector.
  • the antenna 10 with the bent reflector of the conventional example 1 adds the bent portions 12a and 12b to the reflector 11, so that it is necessary to bend the metal plate, attach an L-shaped angle member, etc. There was a problem that the mass increased with increasing.
  • the front-back ratio (FB ratio) in the ⁇ 180 degree direction in the antenna 20 with the bent reflector of the first embodiment is about “ ⁇ 15 dB” when the ratio band is 15%, as is apparent from FIG. 4B.
  • FB ratio front-back ratio
  • the first embodiment it is possible to simplify the shape by forming the bent portions 22a provided on both sides of the reflecting plate 21 into a frame shape with the horizontal elements 24 and the vertical elements 23 made of rod-shaped conductors. Further, the processing cost can be reduced, the antenna mass can be reduced, and the directivity equivalent to that of the antenna with the bent reflector of the conventional example 1 can be maintained. By appropriately selecting the width of the reflecting plate 21 and the dimensions of the horizontal element 24 and the vertical element 23, it is possible to adjust the half width of directivity and the front-back ratio.
  • the bent portion 22a of the reflecting plate 21 is formed using a thin metal plate
  • the bent portion 22a is formed using a round bar conductor such as a columnar or cylindrical shape. May be.
  • the horizontal element 24 may connect the vertical element 23 to the reflecting plate 21 at the middle portion instead of the endmost portion, and the entire bent portion 22 may be formed in a square shape. Three or more may be provided in the central portion by being connected to the reflecting plate 21 or the like.
  • each part constituting the antenna 20 with the bent reflector are not limited to the values shown in the first embodiment, and may be set to other values depending on the frequency band used, characteristics, etc. Of course it is good.
  • the shape of the short side of the reflecting plate 21 having little influence on the characteristics may be an arc shape or the like, which may be included in a substantially rectangular shape.
  • the horizontal element 24 of the bent portion 22a is formed of an insulating member in the antenna 20 with the bent reflector shown in FIGS. That is, conductive vertical elements 23 are provided on both sides of the reflector 21 via horizontal elements 24 made of an insulating member.
  • the dimensions of each part in the second embodiment are set to the same values as in the first embodiment.
  • FIG. 5A shows that the specific band of the antenna with a bent reflector in Example 2 is about 40%, that is, “f L : 0.8 ⁇ f C ”, “f C : 1.0 ⁇ f C ”, “f H : 1.2 ⁇ f C ”, the vertical plane directivity, FIG. 5B shows the horizontal plane directivity.
  • the horizontal element 24 of the reflector bent portion 22a in the antenna with a bent reflector as shown in the second embodiment is formed of an insulating member, the conventional antenna 10 with the bent reflector shown in FIG. It is possible to realize a horizontal plane directivity substantially equivalent to the above.
  • the third embodiment is configured by stacking the antennas with bent reflectors 20 according to the first embodiment in a plurality of stages, for example, two upper and lower stages.
  • the gain can be improved by constructing the antenna 20 with the bent reflector plate in a multistage manner.
  • the case where the antenna 20 with a bent reflector is configured in two stages is shown, but it is needless to say that it may be configured in more stages.
  • the case where the antenna 20 with the folding reflector shown in the first embodiment is configured in a multi-stage is shown.
  • the antenna with the bent reflector shown in the second embodiment is configured in a multi-stage. Also good.
  • FIG. 11 is a trihedral view showing the configuration of an antenna device according to Embodiment 4 of the present invention
  • FIG. 12 is a perspective view thereof.
  • the antenna device 30 includes a rectangular reflecting plate 31 having folded portions (sub-reflecting plates) 31 a on both the left and right sides, a power feeding unit 33 provided substantially at the center of the reflecting plate 31, and the reflecting plate 31.
  • 4 radiating elements 32-1 to 32-4 (hereinafter collectively referred to as radiating elements 32) arranged symmetrically in the vertical and horizontal directions around the feeding portion 33, and along the front center of the reflector 31.
  • Power supply lines 34 and 36 that supply a power supply signal from the power supply unit 33 to each of the radiating elements 32.
  • the antenna device 30 of this example is assumed to be used with vertically polarized waves, and mounting posts are also illustrated.
  • FIG. 13 is an enlarged perspective view of the radiating element 32-2.
  • Each of the radiating elements 32 is a folded dipole antenna, and two inner elements (feed-side elements) 32a corresponding to the dipole antenna and outer elements that linearly connect both ends of the two inner elements ( Folding element) 32b.
  • the folded dipole has the same directivity (gain) as a normal dipole antenna, but has a high impedance and has an advantage that its characteristics can be changed depending on the dimensions.
  • the outer element 32b is an extruded aluminum part having a length d, and its cross section has a channel shape (groove shape, U-shape) having a width c and a depth e.
  • the two inner elements 32a are joined to the outer element 32b at the position of the center of the channel bottom at both ends of the outer element 32b, and a straight line extends to the vicinity of the center of the outer element 32b while maintaining a distance b along the outer surface of the channel of the outer element 32b.
  • It is a flat aluminum part having a width a, which is elongated.
  • c> a that is, the outer element 32b is formed wider than the inner element 32a.
  • the bottoms of the opposing outer elements 32b and the respective surfaces of the inner elements 32a are substantially parallel.
  • the ends of the two inner elements 32a facing each other near the center of the outer element 32b serve as a feeding point for the radiating element 32.
  • the radiating elements 32-1 and 32-2 are arranged so that the outer elements 32b face each other outward (that is, face opposite to each other) and are plane-symmetric (mirror symmetry) with a spacing f. .
  • the feed line 36 is composed of two brass flat plates arranged in parallel on the same plane, and has a characteristic impedance close to the impedance of the radiating element 32.
  • Each of the radiating elements 32-1 and 32-2. Is fed out to the center (mirror surface) between the radiation elements 32-1 and 32-2.
  • the aluminum inner element 32a and the brass feed line 36 are connected via zinc plating or a plate to prevent electrolytic corrosion.
  • the radiating elements 32-1 and 32-2 and the feed line 36 since the appearance formed by the radiating elements 32-1 and 32-2 and the feed line 36 is H-type, these will be referred to as H-type folded antennas.
  • the radiating elements 32-3 and 32-4 constitute an H-shaped folded antenna. These two H-shaped folded antennas are stacked so as to be plane-symmetrical in a plane perpendicular to the mirror surface of the above-described radiating elements 32-1 and 32-2. As a result, the radiating elements 32-1 to 32-4 are stacked. Are lined up on the same plane.
  • the reflection plate 31 is provided in parallel with the same surface, and the center of the reflection plate 31 is substantially equal to the center of the arrangement of the radiation elements 32-1 to 32-4.
  • the width (short side length) A of the reflector 31 is wider than the distance (width of the H-type folded antenna) f between the radiating elements 32-1 and 32-2, and the length B is radiated from the stack distance C. It is longer than the sum of the element lengths d. That is, the reflecting plate 31 is larger than the outer dimension (outer dimension) of the arrangement of the radiating elements 32-1 to 32-4.
  • the long side of the reflector 31 is provided with a folded portion 31a that is folded back to the side opposite to the surface on which the radiating element 32 is provided (that is, rearward in the radiation direction of the antenna device).
  • the turning angle is arbitrary, but is 90 degrees in this example.
  • the folded portion 31 a works to suppress the backward radiation (wraparound) as with the reflector 31.
  • the width (short side length) A of the reflecting plate 31 and the length D of the folded portion 31a can be adjusted, and the width A and the length D may be added by a replaceable member depending on the application.
  • the feed line 34 is a microstrip line composed of a transmission conductor 34-a made of brass and a strip line ground plate 34-b, and both ends thereof are the centers of the feed lines 36 of the two H-type folded antennas.
  • the substantially central portion thereof is connected to the power feeding unit 33.
  • the electric power from the power supply unit 33 is divided into two at the center of the power supply line 34, and further divided into two when being connected to the center of the power supply line 36, and supplied to each radiation element 32.
  • the feed line 34 is provided so that the strip line ground plate 34-b side faces the reflector 31.
  • the strip line ground plate 34-b is supported by the reflector 31 and four brass spacers 35 at both ends thereof. And is also electrically connected.
  • the transmission conductor 34-a is supported at various places from the stripline ground plate 34-b via an insulating spacer (not shown).
  • the H-shaped folded antenna is supported only at the end of the feed line 34, but may be supported directly from the reflector 31 by a plurality of insulating spacers.
  • the feed line 34 can be replaced with various unbalanced lines such as a triplate line.
  • a specific dimension example of the antenna device 30 is expressed as follows.
  • the wavelength of the center frequency fc in the communication frequency band of the antenna device 30 is expressed as ⁇ c
  • the lateral width A of the reflector 31 is 0.3 ⁇ c
  • the length B of the reflector 31 is 1.23 ⁇ c
  • the stack interval (two H-types) The distance between the centers of the folded antennas) C is 0.55 ⁇ c
  • the maximum height H of the protrusion from the reflector 31 is 0.09 ⁇ c
  • the width a of the inner element 32a is 0.06 ⁇ c
  • the inner element 32a and the outer element 32b The distance b is 0.06 ⁇ c
  • the width c of the outer element 32b is 0.04 ⁇ c
  • the radiating element length d is 0.43 ⁇ c
  • the channel depth e of the outer element 32b is 0.06 ⁇ c
  • the radiating element interval f is 0.10 ⁇ c. Is set.
  • FIG. 14 shows the VSWR characteristics of the antenna device 30 set as described above, with the horizontal axis representing the frequency [MHz] and the vertical axis representing VSWR. From FIG. 14, the VSWR characteristic becomes 1.5 or less from 178 MHz to 193 MHz, and a specific bandwidth of 8% is obtained. Further, the vertical plane directivity is shown in FIG. 15, and the horizontal plane directivity is shown in FIG. 15 and FIG. 16, the one-dot line indicates a case of 179 MHz, the solid line indicates a case of 184 MHz, and the two-dot chain line indicates a case of 189 MHz.
  • FIG. 17 shows impedance characteristics in the power feeding section 33 of the antenna device 30.
  • the horizontal axis represents frequency [MHz]
  • the vertical axis represents impedance [ ⁇ ]
  • the real part is a solid line
  • the imaginary part is a broken line. It showed in.
  • this impedance characteristic has a substantially constant impedance (resistance value) from 179 to 192 MHz.
  • the maximum height H of the radiating element 32 from the reflector 31 is as low as 0.09 ⁇ c by bending the left and right ends of the outer element 32b into a groove shape. Even if it is set, the broadband characteristics can be maintained.
  • FIG. 18 is a three-side view of the antenna device according to the fifth embodiment.
  • the antenna device 30 ⁇ / b> A is configured so that the feed lines 34 and 36 are closer to the reflector 31 from the same plane as the center of the radiating element 32, and the feed unit 33 shifted from the center of the reflector is placed at the center of the feed line 34.
  • the difference from the fourth embodiment is that a new feed line 37 to be connected and a cover 38 are provided.
  • the feed line 36 ′ of this example is a line parallel to the reflector 31 like the feed line 36 of the fourth embodiment after descending from the feed point of the radiating element 32 toward the reflector 31.
  • the feed line 34 ′ of this example is the same as the feed line 34 of Example 4 except that the feed line 34 ′ is maintained at the same distance from the reflector 31 as the feed line 36 ′.
  • the cover 38 is an insulating material such as FRP (fiber reinforced plastic), and has a trapezoidal cross-section internal space whose bottom corresponds to the reflector 31.
  • the peripheral edge of the cover 38 projects outwardly in the same plane as the trapezoid base, and is fixed to the reflecting plate 31 at the edge together with the waterproof packing with bolts.
  • the width and length of the cover 38 are substantially the same as the width A and length B of the reflecting plate 31, respectively.
  • the H-shaped folded antenna, the feed line, and the like are housed in a space closed by the reflector 31 and the cover 38.
  • the corner of the cover 38 (the obtuse angle of the trapezoid) is the end of the outer element 32b of the H-shaped folded antenna. It is located in the vicinity.
  • FIG. 19 shows a three-sided view of the feeder line 37 of the antenna device according to the fifth embodiment.
  • the feed line 37 is a triplate line having a structure in which a central conductor on a flat plate is sandwiched between two parallel ground plates, and the height of the center conductor from the reflector 31 is the transmission conductor of the feed line 34 '. This is the same as 34'-a.
  • the feed line 37 is connected to the center of the feed line 34 ′, is directed to the side, then bends at a right angle, and extends to a position directly above the plug provided through the reflector 31.
  • a part of the feed line 37 of this example has a characteristic impedance different from the nominal impedance (50 ⁇ ) of the plug of the antenna device, and acts as if the electrostatic capacity was loaded in parallel with the feed part 33. .
  • the height of the cover 38 can be reduced, and the difficulty of receiving wind pressure and the appearance can be improved.
  • the feed lines 34 ′ and 36 ′ have a lower height from the reflection plate 31, they are configured separately from the reflection plate 31 and enter the cover 38 and travel through the reflection plate. Alternatively, the effect of being less susceptible to corrosion due to moisture condensed in the cover 38 is maintained. Since the feed lines 34 ′ and 36 ′ are separated from the radiating element 32, it can be expected that the coupling with the radiating element is reduced and the antenna design is facilitated.
  • FIG. 20 shows an antenna apparatus according to the sixth embodiment.
  • the radiating element 32 of the antenna device 30B is formed by bending an integral member to form an inner element 32a and an outer element 32b.
  • FIG. 21 shows the VSWR characteristics of the antenna device 30B
  • FIG. 22 shows the vertical plane directivity
  • FIG. 23 shows the horizontal plane directivity
  • FIG. 24 shows the impedance characteristics.
  • FIG. 25 shows an antenna apparatus according to the seventh embodiment.
  • the outer element 32 b of the radiating element 32 is arranged not toward the outer side but toward the reflecting plate 31 so that the width direction of the inner element 32 a and the outer element 32 b is parallel to the reflecting plate 31.
  • FIG. 26 is a diagram illustrating the configuration of the antenna device of the first conventional example.
  • the width A of the reflector is set to about 0.62 ⁇
  • the length B is set to about 2.48 ⁇ .
  • a dipole antenna is provided at a height H on the plate of 0.25 to 0.30 ⁇ .
  • FIG. 27 shows the VSWR characteristics
  • FIG. 28 shows the vertical plane directivity
  • FIG. 29 shows the horizontal plane directivity
  • FIG. 30 shows the impedance characteristics of the antenna device of Conventional Example 3 shown in FIG.
  • a flat dipole is used as the radiating element
  • the stack distance C is 0.55 ⁇ c
  • the radiating element length D is 0.47 ⁇ c
  • the distance H between the radiating element and the reflecting plate is 0.30 ⁇ c. It is. If a large reflector size and protrusion from the reflector are allowed, it is possible to construct a broadband sector antenna conventionally.
  • FIG. 32 shows the VSWR characteristics of the antenna device of Conventional Example 4
  • FIG. 33 shows the vertical plane directivity
  • FIG. 34 shows the horizontal plane directivity
  • FIG. 35 shows the impedance characteristics.
  • the distance from the reflecting plate is shortened to 0.09 ⁇ c as compared to Conventional Example 3, and as a result, the VSWR characteristics are rapidly deteriorated as shown in FIG. That is, when the distance between the reflector and the radiating element (the center thereof) is 0.1 ⁇ or less, the radiating element has a low impedance, making matching difficult.
  • the maximum protrusion height H is fixed to 0.09 ⁇ c by replacing the dipole antenna as in the conventional examples 3 and 2 with an H-shaped folded antenna as shown in FIG.
  • the reflector 31 can be downsized to have a lateral width of about 0.3 ⁇ c and a length of about 1.23 ⁇ c, and the directivity and VSWR can be wideband characteristics.
  • the dimensions shown in the above embodiments may be changed within the same range as the specific bandwidth (for example, 8%).
  • the radiating element 32 is not limited to being fed at the center, and the length of the inner element 32a may be varied.
  • the space between the radiating element 32 and the reflecting plate 31 may be filled with a dielectric other than air to further reduce the size.
  • non-directional antennas may be realized instead of sector antennas by performing polyhedral synthesis of three or more planes.
  • the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment.

Abstract

A reflector (21) is provided with a bent section (22a) on each side. The bent sections (22a) are made from rod-shaped conductors shaped into frames, and each comprises horizontal elements (24) at the top and bottom and a vertical element (23) between the horizontal elements (24). An antenna element (25) is provided in the middle of the front surface of the reflector (21), with a prescribed separation (H). The antenna element (25) is made using, for example, a dipole antenna element, and is provided with a power feed section (27) in the middle thereof.

Description

アンテナ装置Antenna device
　本発明は、通信用基地局や放送用送信等に使用されるアンテナ装置に関する。 The present invention relates to an antenna device used for a communication base station, broadcast transmission, or the like.
　従来、各種通信用基地局で使用されている特定の水平方向領域に対し通信サービスを行うセクタアンテナは、アンテナ素子と反射板を用いた基本構造により特定方向への指向性を強めている。この反射板を用いたアンテナにおいて、反射板の側部に折曲部（副反射板）を設け、反射板幅、折曲寸法を適宜選択して指向性の半値幅とフロントバック比（特にフロントバック比）を調整するように構成したものが提案されている（例えば、特許文献１参照。）。また、反射板の端部に略円柱状の導体表面を有する干渉防止体を該端部に平行に設けてサイドローブレベルを低減するように構成したものが従来から提案されている（例えば、特許文献２参照。）。 Conventionally, sector antennas that provide communication services for specific horizontal areas used in various communication base stations have enhanced directivity in specific directions due to the basic structure using antenna elements and reflectors. In an antenna using this reflector, a bent portion (sub-reflector) is provided on the side of the reflector, and the width of the reflector and the bending dimension are selected as appropriate, so that the half width of the directivity and the front-back ratio (particularly the front The one configured to adjust the (back ratio) has been proposed (see, for example, Patent Document 1). In addition, an interference prevention body having a substantially cylindrical conductor surface at the end of the reflector is provided in parallel with the end to reduce the side lobe level (for example, patents). Reference 2).
特開平５－２８３９２９号公報JP-A-5-283929 特開２００１－１７７３３６号公報JP 2001-177336 A
　ところが、上記従来技術によれば、ＶＨＦ（very high frequency）帯等を使用周波数帯とする場合には、アンテナ形状が大きくなり、質量の増大、設置、外観等が問題となっている。 However, according to the above prior art, when the VHF (very high frequency) band or the like is used, the shape of the antenna becomes large, which causes problems such as an increase in mass, installation, and appearance.
　この発明は上記事情に着目してなされたもので、アンテナ形状を小型化し、且つ指向性、広帯域性を維持するアンテナ装置を提供することにある。 The present invention has been made paying attention to the above circumstances, and it is an object of the present invention to provide an antenna device that can reduce the antenna shape and maintain directivity and broadband characteristics.
　本発明の一態様は、略方形状に形成された反射板と、前記反射板の前面に所定の間隔を保って設けられるアンテナ素子と、前記反射板の両側部に設けられる２つの折曲部とを具備し、前記折曲部は、前記側部の後方に前記アンテナ素子の偏波方向と同一方向に設けられる棒状導体の垂直素子と、前記垂直素子を複数箇所において前記反射板と結合する水平素子とを有して、枠形状に形成されるアンテナ装置を提供する。 One aspect of the present invention is a reflector that is formed in a substantially square shape, an antenna element that is provided on the front surface of the reflector with a predetermined interval, and two bent portions that are provided on both sides of the reflector. And the bent part is coupled to the reflector at a plurality of locations, and a vertical element of a rod-like conductor provided behind the side part in the same direction as the polarization direction of the antenna element. An antenna device having a horizontal element and formed in a frame shape is provided.
　また、本発明の他の態様は、所定の平面上で、上下対称及び左右対称に配置された４個の折返しダイポールアンテナと、前記所定の平面と水平で、前記４個の折返しダイポールアンテナの配置の外側寸法よりも大きな平板状の反射板と、前記反射板の前面中央に沿って前記反射板とは別体に設けられ、前記放射素子のそれぞれに給電部からの給電信号を供給する給電線路とを具備し、前記折返しダイポールアンテナのそれぞれは、ダイポールアンテナ様の１対の給電側素子と、前記１対の給電側素子の両端を直線状につなぐ略λ／２（λは使用周波数における波長）長の折返し素子を備え、前記折返し素子は、溝状の断面を押し出た形状をなし、該溝の底の外側において前記１対の給電側素子と対向し、前記溝の幅は、前記１対の給電側素子の幅よりも広く形成され、前記反射板からの前記折返し素子の最大距離が、０．１λ以下であることを特徴とするアンテナ装置を提供する。 According to another aspect of the present invention, there are provided four folded dipole antennas arranged vertically and horizontally symmetrically on a predetermined plane, and an arrangement of the four folded dipole antennas horizontally with the predetermined plane. And a feed line that is provided separately from the reflector along the center of the front surface of the reflector, and that feeds a feed signal from the feed section to each of the radiating elements. Each of the folded dipole antennas includes a pair of feeding-side elements like a dipole antenna and a substantially λ / 2 (λ is a wavelength at an operating frequency) that linearly connects both ends of the pair of feeding-side elements. ) Having a long folding element, the folding element is formed by extruding a groove-shaped cross section, facing the pair of power feeding elements on the outside of the bottom of the groove, and the width of the groove is A pair of feed-side elements The antenna device is characterized in that the maximum distance of the folded element from the reflector is 0.1λ or less.
　すなわちこの発明によれば、アンテナ形状を小型化し、且つ指向性、広帯域性を維持することができるアンテナ装置を提供することができる。 That is, according to the present invention, it is possible to provide an antenna device capable of reducing the antenna shape and maintaining the directivity and the broadband property.
図１は、本発明の実施例１の折曲げ反射板付きアンテナの構成を示す斜視図である。FIG. 1 is a perspective view showing a configuration of an antenna with a bent reflector according to a first embodiment of the present invention. 図２は、実施例１のアンテナの側面図である。FIG. 2 is a side view of the antenna according to the first embodiment. 図３Ａは、実施例１のアンテナの比帯域約４０％における垂直面指向性を示す図である。FIG. 3A is a diagram illustrating vertical plane directivity in the specific band of about 40% of the antenna of the first embodiment. 図３Ｂは、実施例１のアンテナの比帯域約４０％における水平面指向性を示す図である。FIG. 3B is a diagram illustrating the horizontal plane directivity in the specific band of about 40% of the antenna of the first embodiment. 図４Ａは、実施例１のアンテナの比帯域約１５％における垂直面指向性を示す図である。FIG. 4A is a diagram illustrating the vertical plane directivity in the specific band of about 15% of the antenna of the first embodiment. 図４Ｂは、実施例１のアンテナの比帯域約１５％における水平面指向性を示す図である。FIG. 4B is a diagram illustrating the horizontal plane directivity in the specific band of about 15% of the antenna of the first embodiment. 図５Ａは、実施例２のアンテナの比帯域約４０％における垂直面指向性を示す図である。FIG. 5A is a diagram illustrating the vertical plane directivity in the specific band of about 40% of the antenna of the second embodiment. 図５Ｂは、実施例２のアンテナの比帯域約４０％における水平面指向性を示す図である。FIG. 5B is a diagram illustrating horizontal plane directivity in the specific band of about 40% of the antenna of the second embodiment. 図６は、本発明の実施例３の反射板付きアンテナを多段化した場合の構成例を示す斜視図である。FIG. 6 is a perspective view illustrating a configuration example when the antenna with a reflector according to the third embodiment of the present invention is multistaged. 図７は、従来例１の折曲げ反射板付きアンテナの構成を示す斜視図である。FIG. 7 is a perspective view showing the configuration of the antenna with a bent reflector of Conventional Example 1. FIG. 図８Ａは、従来例１のアンテナの比帯域約４０％における垂直面指向性を示す図である。FIG. 8A is a diagram showing the directivity of the vertical plane in the specific band of about 40% of the antenna of Conventional Example 1. 図８Ｂは、従来例１のアンテナの比帯域約４０％における水平面指向性を示す図である。FIG. 8B is a diagram illustrating horizontal plane directivity in the specific band of about 40% of the antenna of Conventional Example 1. 図９は、従来例２の折曲部の無い反射板付きアンテナの構成を示す斜視図である。FIG. 9 is a perspective view showing a configuration of an antenna with a reflector without a bent portion in Conventional Example 2. FIG. 図１０Ａは、従来例２のアンテナの比帯域約４０％における垂直面指向性を示す図である。FIG. 10A is a diagram illustrating the directivity of the vertical plane in the specific band of about 40% of the antenna of Conventional Example 2. 図１０Ｂは、従来例２のアンテナの比帯域約４０％における水平面指向性を示す図である。FIG. 10B is a diagram illustrating horizontal plane directivity of the antenna of Conventional Example 2 in a specific band of about 40%. 図１１は、本発明の実施例４に係るアンテナ装置の構成を示す三面図である。FIG. 11 is a three-view diagram illustrating the configuration of the antenna device according to the fourth embodiment of the present invention. 図１２は、図１１のアンテナ装置の斜視図である。12 is a perspective view of the antenna device of FIG. 図１３は、図１１のアンテナ装置の放射素子１２－２の斜視図である。FIG. 13 is a perspective view of the radiating element 12-2 of the antenna apparatus of FIG. 図１４は、図１１のアンテナ装置のＶＳＷＲ特性を示す図である。FIG. 14 is a diagram showing the VSWR characteristics of the antenna device of FIG. 図１５は、図１１のアンテナ装置の垂直面指向性を示す図である。FIG. 15 is a diagram illustrating the directivity of the vertical plane of the antenna device of FIG. 図１６は、図１１のアンテナ装置の水平面指向性を示す図である。FIG. 16 is a diagram illustrating the horizontal plane directivity of the antenna device of FIG. 11. 図１７は、図１１のアンテナ装置のインピーダンス特性を示す図である。FIG. 17 is a diagram illustrating impedance characteristics of the antenna device of FIG. 図１８は、実施例５に係るアンテナ装置の３面図である。FIG. 18 is a trihedral view of the antenna device according to the fifth embodiment. 図１９は、図１８のアンテナ装置の給電線路１７の３面図である。FIG. 19 is a three-plane view of the feed line 17 of the antenna device of FIG. 図２０は、本発明に係る実施例６のアンテナ装置の構成を示す図である。FIG. 20 is a diagram illustrating the configuration of the antenna device according to the sixth embodiment of the present invention. 図２１は、実施例６のアンテナ装置のＶＳＷＲ特性を示す図である。FIG. 21 is a diagram illustrating the VSWR characteristics of the antenna device according to the sixth embodiment. 図２２は、実施例６のアンテナ装置の垂直面指向性を示す図である。FIG. 22 is a diagram illustrating the directivity of the vertical plane of the antenna device according to the sixth embodiment. 図２３は、実施例６のアンテナ装置の水平面指向性を示す図である。FIG. 23 is a diagram illustrating the horizontal plane directivity of the antenna device according to the sixth embodiment. 図２４は、実施例６のアンテナ装置のインピーダンス特性を示す図である。FIG. 24 is a diagram illustrating impedance characteristics of the antenna device according to the sixth embodiment. 図２５は、本発明に係る実施例７のアンテナ装置の構成を示す図である。FIG. 25 is a diagram illustrating the configuration of the antenna device according to the seventh embodiment of the present invention. 図２６は、従来例３のアンテナ装置の構成を示す図である。FIG. 26 is a diagram illustrating the configuration of the antenna device of the third conventional example. 図２７は、従来例３のアンテナ装置のＶＳＷＲ特性を示す図である。FIG. 27 is a diagram illustrating the VSWR characteristics of the antenna device of Conventional Example 3. 図２８は、従来例３のアンテナ装置の垂直面指向性を示す図である。FIG. 28 is a diagram illustrating the directivity on the vertical plane of the antenna device of Conventional Example 3. 図２９は、従来例３のアンテナ装置の水平面指向性を示す図である。FIG. 29 is a diagram illustrating the horizontal plane directivity of the antenna device of Conventional Example 3. 図３０は、従来例３のアンテナ装置のインピーダンス特性を示す図である。FIG. 30 is a diagram illustrating impedance characteristics of the antenna device according to Conventional Example 3. 図３１は、従来例４のアンテナ装置の構成を示す図である。FIG. 31 is a diagram illustrating a configuration of an antenna device of Conventional Example 4. 図３２は、従来例４のアンテナ装置のＶＳＷＲ特性を示す図である。FIG. 32 is a diagram showing the VSWR characteristics of the antenna device of Conventional Example 4. 図３３は、従来例４のアンテナ装置の垂直面指向性を示す図である。FIG. 33 is a diagram showing the vertical plane directivity of the antenna device of Conventional Example 4. 図３４は、従来例４のアンテナ装置の水平面指向性を示す図である。FIG. 34 is a diagram illustrating the horizontal plane directivity of the antenna device of Conventional Example 4. 図３５は、従来例４のアンテナ装置のインピーダンス特性を示す図である。FIG. 35 is a diagram illustrating impedance characteristics of the antenna device of the conventional example 4.
　以下、本発明の実施の形態について図面を参照して詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
　図１は実施例１に係る折曲げ反射板付きアンテナ２０の構成を示す斜視図、図２は同折曲げ反射板付きアンテナ２０の側面図である。図１に用いられる座標系は右手系であり、Ｘ軸方向を前面、Ｚ軸方向を鉛直（つまり上下高さ方向）とする。 FIG. 1 is a perspective view showing a configuration of an antenna 20 with a bent reflector according to the first embodiment, and FIG. 2 is a side view of the antenna 20 with the bent reflector. The coordinate system used in FIG. 1 is a right-handed system, where the X-axis direction is the front surface and the Z-axis direction is vertical (that is, the vertical height direction).
　図１及び図２において、２１は金属板を用いて略方形状に形成した平板の反射板で、その長手方向がＺ軸と平行となるようＹ－Ｚ平面に設けられる。そして、長辺の両側部において折曲部２２ａ、２２ｂとそれぞれ固着されている。これらの折曲部２２は、棒状導体例えば細い幅の棒状金属板を用いて枠形状に形成したもので、反射板２１の２つの長辺の後方にそれと平行にそれぞれ設けられる垂直素子２３と、垂直素子２３を上下２箇所において反射板と結合する水平素子２４と、この水平素子２４間に設けられる垂直素子２３により構成される。本実施例の折曲部２２は、水平素子２４は垂直素子２３の両端部からＸ軸方向に設けられており、その長さ（折曲部２２ａの折曲げ幅（水平素子２４の長さ）はＣとする。また、縦幅（垂直素子２３の長さ）は反射板２１の縦幅Ｂと同じ値に設定され、全体としてコの字状枠体となる。上記折曲部２２ａは、水平素子２４が反射板２１の四隅の角部に例えばネジ止め等によって装着される。 1 and 2, reference numeral 21 denotes a flat reflecting plate formed in a substantially square shape using a metal plate, and is provided on the YZ plane so that its longitudinal direction is parallel to the Z axis. And it fixes to bending part 22a, 22b in the both sides of a long side, respectively. These bent portions 22 are formed in a frame shape using a rod-shaped conductor, for example, a narrow-width rod-shaped metal plate, and vertical elements 23 respectively provided in parallel to and behind the two long sides of the reflecting plate 21; The vertical element 23 is composed of a horizontal element 24 that couples the reflector to the reflector at two locations, and a vertical element 23 provided between the horizontal elements 24. In the bent portion 22 of the present embodiment, the horizontal element 24 is provided in the X-axis direction from both ends of the vertical element 23, and its length (the bent width of the bent portion 22a (the length of the horizontal element 24)). Is set to the same value as the vertical width B of the reflecting plate 21. The bent portion 22a has a U-shaped frame as a whole. The horizontal elements 24 are attached to the corners of the four corners of the reflector 21 by, for example, screwing.
　上記反射板２１の前面側の中央部には、アンテナ素子２５が絶縁支持部材により所定の間隔Ｈを保って設けられる。このアンテナ素子２５は、例えば２つの板状素子２６ａ、２６ｂを、反射板２１の長手方向（上下方向）に直線状に配置してなるダイポールアンテナ素子で、その中央部、すなわち板状素子２６ａ、２６ｂの近接側端部に給電部２７が設けられる。これにより、反射板付きアンテナ２０は、垂直偏波の略Ｘ軸方向の主ビームを有し、主ビームの方向を前面と呼ぶ。垂直素子２３は、偏波方向に設けられていることになる。 The antenna element 25 is provided at a central portion on the front side of the reflector 21 with a predetermined interval H by an insulating support member. The antenna element 25 is a dipole antenna element in which, for example, two plate- like elements 26a and 26b are linearly arranged in the longitudinal direction (vertical direction) of the reflecting plate 21, and the central portion thereof, that is, the plate-like element 26a, A power feeding section 27 is provided at the end on the near side of 26b. Thus, the antenna with a reflector 20 has a main beam in the substantially X-axis direction of vertical polarization, and the direction of the main beam is referred to as the front surface. The vertical element 23 is provided in the polarization direction.
　上記折曲げ反射板付きアンテナ２０において、反射板２１の横幅Ａ、縦幅Ｂ、折曲部２２ａの折曲げ幅Ｃ、アンテナ素子長Ｄ、アンテナ素子幅ｄ、反射板２１とアンテナ素子２５との間隔Ｈ、折曲部２２ａの垂直素子２３の幅ｃ１、水平素子２４の幅ｃ２の値を例えば次のように設定した場合の垂直面指向性を図３Ａに、水平面指向性を図３Ｂに示す。 In the antenna 20 with the bent reflector, the horizontal width A, the vertical width B of the reflector 21, the bent width C of the bent portion 22a, the antenna element length D, the antenna element width d, the reflector 21 and the antenna element 25 FIG. 3A shows the vertical plane directivity and FIG. 3B shows the horizontal plane directivity when the interval H, the width c1 of the vertical element 23 of the bent portion 22a, and the width c2 of the horizontal element 24 are set as follows, for example. .
　　Ａ：０．２４８λｃ　
　　Ｂ：０．８λｃ　
　　Ｃ：０．１５５λｃ　
　　Ｄ：０．４５３λｃ　
　　ｄ：０．０５λｃ　
　　Ｈ：０．０６２λｃ　
　ｃ１：０．００６λｃ　
　ｃ２：０．００６λｃ
　上記λｃは折曲げ反射板付きアンテナ２０の通信周波数帯域における中心周波数ｆＣの波長を示している。 A: 0.248λc
B: 0.8λc
C: 0.155λc
D: 0.453λc
d: 0.05λc
H: 0.062λc
c1: 0.006λc
c2: 0.006λc
Λc indicates the wavelength of the center frequency f C in the communication frequency band of the antenna 20 with the bent reflector.
　上記図３Ａ（垂直面指向性）及び図３Ｂ（水平面指向性）において、実線は通信周波数帯域の中心周波数ｆＣ例えば１８６ＭＨｚにおける特性、一点鎖線は通信周波数帯域の最低周波数ｆＬ（ｆＬ＝０．８×ｆＣ）における特性、破線は通信周波数帯域の最高周波数ｆＨ（ｆＨ＝１．２×ｆＣ）における特性を示している。このときの比帯域（ｆＬ～ｆＨ）は約４０％である。 In FIG. 3A (vertical plane directivity) and FIG. 3B (horizontal plane directivity), the solid line is the characteristic at the center frequency f C of the communication frequency band, for example, 186 MHz, and the alternate long and short dash line is the lowest frequency f L (f L = 0) of the communication frequency band. .8 × f C ), the broken line indicates the characteristic at the highest frequency f H (f H = 1.2 × f C ) in the communication frequency band. The ratio band (f L to f H ) at this time is about 40%.
　また、図４Ａは上記折曲げ反射板付きアンテナ２０において、比帯域を約１５％、すなわち「ｆＬ：０．９２５×ｆＣ」、「ｆＣ：１．０×ｆＣ」、「ｆＨ：１．０７５×ｆＣ」とした場合の垂直面指向性、図４Ｂは同水平面指向性を示している。 FIG. 4A shows the antenna 20 with a bent reflector having a specific band of about 15%, that is, “f L : 0.925 × f C ”, “f C : 1.0 × f C ”, “f H : 1.075 × f C ”, and FIG. 4B shows the horizontal plane directivity.
　ここで、比較のため、従来例１、２の構成を示して説明を行う。図７は、従来例１の反射板の側部に折曲部を設けた従来の折曲げ反射板付きアンテナ１０の構成を示す斜視図である。図７において、１１は金属板を用いて構成した反射板で、両側部に後方（主ビームと反対方向）に折曲げた平板状の折曲部１２ａ、１２ｂを備えている。上記反射板１１の前面側の中央部には、所定の間隔Ｈを保ってアンテナ素子１３が設けられる。このアンテナ素子１３は、２つの板状素子１４ａ、１４ｂを直線状に配置してなるダイポールアンテナ素子で、その中央部、すなわち板状素子１４ａ、１４ｂの近接側端部に給電部１５が設けられる。 Here, for comparison, the configurations of the conventional examples 1 and 2 are shown and described. FIG. 7 is a perspective view illustrating a configuration of a conventional antenna 10 with a bent reflector in which a bent portion is provided on a side portion of the reflector of the first conventional example. In FIG. 7, reference numeral 11 denotes a reflecting plate configured using a metal plate, and includes flat plate-like bent portions 12 a and 12 b that are bent rearward (in a direction opposite to the main beam) on both sides. An antenna element 13 is provided at a central portion on the front side of the reflection plate 11 with a predetermined interval H maintained. This antenna element 13 is a dipole antenna element formed by arranging two plate- like elements 14a and 14b in a straight line, and a feeding portion 15 is provided at the center thereof, that is, the adjacent end of the plate- like elements 14a and 14b. .
　上記反射板１１の横幅Ａ、縦幅Ｂ、折曲部１２ａ、１２ｂの折曲げ幅Ｃ、アンテナ素子長Ｄ、アンテナ素子幅ｄ、反射板１１とアンテナ素子１３との間隔Ｈの値は、上記実施例１と同様に設定される。 The horizontal width A and vertical width B of the reflector 11, the bending width C of the bent portions 12 a and 12 b, the antenna element length D, the antenna element width d, and the value of the distance H between the reflector 11 and the antenna element 13 are as described above. The setting is the same as in the first embodiment.
　図８Ａは各部の寸法が上記の値に設定された折曲げ反射板付きアンテナ１０の垂直面指向性を示し、図８Ｂは同アンテナの水平面指向性を示している。上記図８Ａ、８Ｂにおいて、実線は通信周波数帯域の中心周波数ｆＣ（１８６ＭＨｚ）における特性、一点鎖線は通信周波数帯域の最低周波数ｆＬ（ｆＬ＝０．８×ｆＣ）における特性、破線は通信周波数帯域の最高周波数ｆＨ（ｆＨ＝１．２×ｆＣ）における特性を示している。 FIG. 8A shows the vertical plane directivity of the antenna 10 with the bent reflector whose dimensions are set to the above values, and FIG. 8B shows the horizontal plane directivity of the antenna. 8A and 8B, the solid line is the characteristic at the center frequency f C (186 MHz) of the communication frequency band, the alternate long and short dash line is the characteristic at the lowest frequency f L (f L = 0.8 × f C ) of the communication frequency band, and the broken line is The characteristic at the highest frequency f H (f H = 1.2 × f C ) of the communication frequency band is shown.
　上記折曲げ反射板付きアンテナ１０におけるフロントバック比（ＦＢ比：Front to Back ratio）は、－１８０度方向にて最低周波数ｆＬでは約「－１６ｄＢ」、中心周波数ｆＣ及び最高周波数ｆＨでは約「－１８ｄＢ」であった。このときの比帯域（ｆＬ～ｆＨ）は約４０％である。 The front-to-back ratio (FB ratio) in the antenna 10 with the bent reflector is about “−16 dB” at the lowest frequency f L in the −180 degree direction, and at the center frequency f C and the highest frequency f H. About “−18 dB”. The ratio band (f L to f H ) at this time is about 40%.
　図９は、従来例２として、上記折曲げ反射板付きアンテナ１０において、折曲部１２ａ、１２ｂを設けなかった場合の反射板付きアンテナ１０Ａの構成例を示している。この折曲部の無い反射板付きアンテナ１０Ａの各部の寸法は、上記折曲げ反射板付きアンテナ１０と同じである。 FIG. 9 shows a configuration example of a reflector-equipped antenna 10A as the conventional example 2 when the bent portions 12a and 12b are not provided in the antenna 10 with a folded reflector. The dimensions of each part of the antenna 10A with a reflector without a bent part are the same as those of the antenna 10 with a reflector.
　上記折曲部の無い反射板付きアンテナ１０Ａの比帯域約４０％における垂直面指向性を図１０Ａ、水平面指向性を図１０Ｂに示す。図１０Ａ、１０Ｂにおいて、実線は通信周波数帯域の中心周波数ｆＣ（１８６ＭＨｚ）における特性、一点鎖線は通信周波数帯域の最低周波数ｆＬ（ｆＬ＝０．８×ｆＣ）における特性、破線は通信周波数帯域の最高周波数ｆＨ（ｆＨ＝１．２×ｆＣ）における特性を示している。 FIG. 10A shows a vertical plane directivity and FIG. 10B shows a horizontal plane directivity in a specific band of about 40% of the antenna 10A with a reflector without the bent portion. 10A and 10B, the solid line is the characteristic at the center frequency f C (186 MHz) of the communication frequency band, the alternate long and short dash line is the characteristic at the lowest frequency f L (f L = 0.8 × f C ) of the communication frequency band, and the broken line is the communication. The characteristic at the highest frequency f H (f H = 1.2 × f C ) in the frequency band is shown.
　上記折曲部の無い反射板付きアンテナ１０Ａは、指向性の半値幅は図７に示した折曲げ反射板付きアンテナ１０と略同じであるが、－１８０度方向におけるフロントバック比は約「－１５ｄＢ」であり、折曲げ反射板付きアンテナ１０に比較して劣化している。 The reflector-equipped antenna 10A without the bent portion has a directivity half-width of approximately the same as the antenna 10 with the folded reflector shown in FIG. 7, but the front-back ratio in the −180 degree direction is about “− 15 dB ", which is deteriorated compared to the antenna 10 with the bent reflector.
　しかし、従来例１の折曲げ反射板付きアンテナ１０は、反射板１１に折曲部１２ａ、１２ｂを付加するため、金属板の曲げ加工やＬ型アングル材の取付け等が必要となり、加工コストが上昇すると共に質量が増大するという問題があった。 However, the antenna 10 with the bent reflector of the conventional example 1 adds the bent portions 12a and 12b to the reflector 11, so that it is necessary to bend the metal plate, attach an L-shaped angle member, etc. There was a problem that the mass increased with increasing.
　これに対し、本実施例１の折曲げ反射板付きアンテナ２０における－１８０度方向のフロントバック比（ＦＢ比）は、上記図４Ｂから明らかなように比帯域が１５％において約「－１５ｄＢ」となっており、図７に示した従来の折曲げ反射板付きアンテナ１０と略同等の水平面指向性を実現している。 In contrast, the front-back ratio (FB ratio) in the −180 degree direction in the antenna 20 with the bent reflector of the first embodiment is about “−15 dB” when the ratio band is 15%, as is apparent from FIG. 4B. Thus, the horizontal plane directivity substantially equivalent to that of the conventional antenna 10 with a bent reflector shown in FIG. 7 is realized.
　上記実施例１で示したように反射板２１の両側部に設ける折曲部２２ａを棒状導体からなる水平素子２４及び垂直素子２３により枠形状に形成することにより、形状を簡易化することができ、加工コストを低減し得ると共に、アンテナ質量を低減でき、且つ、従来例１の折曲げ反射板付きアンテナと同等の指向性を維持することができる。反射板２１の幅、水平素子２４及び垂直素子２３の寸法を適宜選択することにより、指向性の半値幅とフロントバック比を調整することが可能である。 As shown in the first embodiment, it is possible to simplify the shape by forming the bent portions 22a provided on both sides of the reflecting plate 21 into a frame shape with the horizontal elements 24 and the vertical elements 23 made of rod-shaped conductors. Further, the processing cost can be reduced, the antenna mass can be reduced, and the directivity equivalent to that of the antenna with the bent reflector of the conventional example 1 can be maintained. By appropriately selecting the width of the reflecting plate 21 and the dimensions of the horizontal element 24 and the vertical element 23, it is possible to adjust the half width of directivity and the front-back ratio.
　なお、上記実施例１では、垂直偏波を例示したが、Ｘ軸周りに９０度回転させ水平偏波で使用してもよい。また、反射板２１の折曲部２２ａを細い幅の金属板を用いて形成した場合について示したが、その他、例えば円柱状や円筒状等の丸棒導体を用いて折曲部２２ａを形成しても良い。また、水平素子２４が垂直素子２３をその最端部ではなく途中箇所で反射板２１に連結させ、折曲部２２全体をΠ字状に形成してもよく、水平素子２４は垂直素子２３の中央部でも反射板２１と連結させるなどして３個以上備えられても良い。 In the first embodiment, vertical polarization is illustrated, but it may be rotated 90 degrees around the X axis and used with horizontal polarization. Moreover, although the case where the bent portion 22a of the reflecting plate 21 is formed using a thin metal plate has been shown, the bent portion 22a is formed using a round bar conductor such as a columnar or cylindrical shape. May be. Further, the horizontal element 24 may connect the vertical element 23 to the reflecting plate 21 at the middle portion instead of the endmost portion, and the entire bent portion 22 may be formed in a square shape. Three or more may be provided in the central portion by being connected to the reflecting plate 21 or the like.
　また、折曲げ反射板付きアンテナ２０を構成する各部の寸法は、上記実施例１に示した値に限定されるものではなく、使用周波数帯域や特性等に応じて他の値に設定しても良いことは勿論である。例えば特性への影響が少ない反射板２１の短辺の形状は、円弧状などでも良く、それらも略方形に含まれうる。 In addition, the dimensions of each part constituting the antenna 20 with the bent reflector are not limited to the values shown in the first embodiment, and may be set to other values depending on the frequency band used, characteristics, etc. Of course it is good. For example, the shape of the short side of the reflecting plate 21 having little influence on the characteristics may be an arc shape or the like, which may be included in a substantially rectangular shape.
　この実施例２は、上記図１及び図２に示した折曲げ反射板付きアンテナ２０において、折曲部２２ａの水平素子２４を絶縁部材により形成している。すなわち、反射板２１の両側に絶縁部材からなる水平素子２４を介して導電性の垂直素子２３を設けたものである。この実施例２における各部の寸法は、上記実施例１の場合と同じ値に設定される。 In Example 2, the horizontal element 24 of the bent portion 22a is formed of an insulating member in the antenna 20 with the bent reflector shown in FIGS. That is, conductive vertical elements 23 are provided on both sides of the reflector 21 via horizontal elements 24 made of an insulating member. The dimensions of each part in the second embodiment are set to the same values as in the first embodiment.
　図５Ａは実施例２における折曲げ反射板付きアンテナの比帯域を約４０％、すなわち、「ｆＬ：０．８×ｆＣ」、「ｆＣ：１．０×ｆＣ」、「ｆＨ：１．２×ｆＣ」とした場合の垂直面指向性、図５Ｂは同水平面指向性を示している。 FIG. 5A shows that the specific band of the antenna with a bent reflector in Example 2 is about 40%, that is, “f L : 0.8 × f C ”, “f C : 1.0 × f C ”, “f H : 1.2 × f C ”, the vertical plane directivity, FIG. 5B shows the horizontal plane directivity.
　上記実施例２に示したように折曲げ反射板付きアンテナにおける反射板折曲部２２ａの水平素子２４を絶縁部材により構成した場合においても、図７に示した従来の折曲げ反射板付きアンテナ１０と略同等の水平面指向性を実現することができる。 Even when the horizontal element 24 of the reflector bent portion 22a in the antenna with a bent reflector as shown in the second embodiment is formed of an insulating member, the conventional antenna 10 with the bent reflector shown in FIG. It is possible to realize a horizontal plane directivity substantially equivalent to the above.
　この実施例３は、図６に示すように実施例１に係る折曲げ反射板付きアンテナ２０を複数段例えば上下２段にスタックして構成したものである。このように折曲げ反射板付きアンテナ２０を多段化して構成することにより、利得を向上することができる。 As shown in FIG. 6, the third embodiment is configured by stacking the antennas with bent reflectors 20 according to the first embodiment in a plurality of stages, for example, two upper and lower stages. Thus, the gain can be improved by constructing the antenna 20 with the bent reflector plate in a multistage manner.
　上記実施例３では、折曲げ反射板付きアンテナ２０を２段に構成した場合について示したが、更に多段に構成しても良いことは勿論である。 In the third embodiment, the case where the antenna 20 with a bent reflector is configured in two stages is shown, but it is needless to say that it may be configured in more stages.
　また、この実施例３では、実施例１に示した折曲げ反射板付きアンテナ２０を多段に構成した場合について示したが、実施例２に示した折曲げ反射板付きアンテナを多段に構成してもよい。 In the third embodiment, the case where the antenna 20 with the folding reflector shown in the first embodiment is configured in a multi-stage is shown. However, the antenna with the bent reflector shown in the second embodiment is configured in a multi-stage. Also good.
　図１１は、本発明の実施例４に係るアンテナ装置の構成を示す三面図、図１２はその斜視図である。図１１や図１２において、アンテナ装置３０は、左右両側に折返部（副反射板）３１ａを有する長方形の反射板３１と、反射板３１の略中央に設けられた給電部３３と、反射板３１の前面に、給電部３３を中心に上下左右対称に配置された４個の放射素子３２－１～３２－４（以下、放射素子３２と総称する。）と、反射板３１の前面中央に沿って設けられ、放射素子３２のそれぞれに給電部３３からの給電信号を供給する給電線路３４、３６とを備える。本例のアンテナ装置３０は、垂直偏波で使用することを想定しており、取付け用の支柱も図示してある。 FIG. 11 is a trihedral view showing the configuration of an antenna device according to Embodiment 4 of the present invention, and FIG. 12 is a perspective view thereof. 11 and 12, the antenna device 30 includes a rectangular reflecting plate 31 having folded portions (sub-reflecting plates) 31 a on both the left and right sides, a power feeding unit 33 provided substantially at the center of the reflecting plate 31, and the reflecting plate 31. 4 radiating elements 32-1 to 32-4 (hereinafter collectively referred to as radiating elements 32) arranged symmetrically in the vertical and horizontal directions around the feeding portion 33, and along the front center of the reflector 31. Power supply lines 34 and 36 that supply a power supply signal from the power supply unit 33 to each of the radiating elements 32. The antenna device 30 of this example is assumed to be used with vertically polarized waves, and mounting posts are also illustrated.
　図１３は、放射素子３２－２の拡大斜視図である。上記放射素子３２のそれぞれは、折返しダイポール（folded dipole）アンテナであり、ダイポールアンテナに相当する２つの内側素子（給電側素子）３２ａと、２つの内側素子の両端を直線的に接続する外側素子（折返し素子）３２ｂとを備える。折返しダイポールは通常のダイポールアンテナと同じ指向性（利得）でありながら、インピーダンスが高く、寸法によりにより特性を変えられる利点がある。 FIG. 13 is an enlarged perspective view of the radiating element 32-2. Each of the radiating elements 32 is a folded dipole antenna, and two inner elements (feed-side elements) 32a corresponding to the dipole antenna and outer elements that linearly connect both ends of the two inner elements ( Folding element) 32b. The folded dipole has the same directivity (gain) as a normal dipole antenna, but has a high impedance and has an advantage that its characteristics can be changed depending on the dimensions.
　外側素子３２ｂは、長さｄの押し出し形状のアルミ製部品であり、その断面は、幅ｃ、深さｅのチャネル状（溝状、コの字状）になっている。２つの内側素子３２ａは、外側素子３２ｂの両端のチャネル底部中央の位置で外側素子３２ｂと接合し、外側素子３２ｂのチャネル外側の面に沿って間隔ｂを保って外側素子３２ｂの中央付近まで直線的に伸びる、幅ａの平板状のアルミ製部品である。本例において、ｃ＞ａ、すなわち外側素子３２ｂは内側素子３２ａより幅広に形成される。対向する外側素子３２ｂの底部と内側素子３２ａのそれぞれの面は略平行である。外側素子３２ｂの中央付近で対向する２つの内側素子３２ａの端部が、この放射素子３２の給電点となる。 The outer element 32b is an extruded aluminum part having a length d, and its cross section has a channel shape (groove shape, U-shape) having a width c and a depth e. The two inner elements 32a are joined to the outer element 32b at the position of the center of the channel bottom at both ends of the outer element 32b, and a straight line extends to the vicinity of the center of the outer element 32b while maintaining a distance b along the outer surface of the channel of the outer element 32b. It is a flat aluminum part having a width a, which is elongated. In this example, c> a, that is, the outer element 32b is formed wider than the inner element 32a. The bottoms of the opposing outer elements 32b and the respective surfaces of the inner elements 32a are substantially parallel. The ends of the two inner elements 32a facing each other near the center of the outer element 32b serve as a feeding point for the radiating element 32.
　放射素子３２－１と３２－２は、間隔ｆでもって、それぞれの外側素子３２ｂが互いに外側を向き（すなわち相手と反対を向き）、かつ面対称（鏡映対称）となるように配置される。 The radiating elements 32-1 and 32-2 are arranged so that the outer elements 32b face each other outward (that is, face opposite to each other) and are plane-symmetric (mirror symmetry) with a spacing f. .
　給電線路３６は、同一面上に並設される２つの真鍮製の平板で構成され、放射素子３２のインピーダンスに近い特性インピーダンスを有する給電線路であり、放射素子３２－１と３２－２のそれぞれの給電点を、放射素子３２－１と３２－２の間の中央（鏡映面）まで引き出す。なお、アルミ製の内側素子３２ａと真鍮製の給電線路３６とは、亜鉛のめっきまたは板を介して接続し、電蝕を防止する。 The feed line 36 is composed of two brass flat plates arranged in parallel on the same plane, and has a characteristic impedance close to the impedance of the radiating element 32. Each of the radiating elements 32-1 and 32-2. Is fed out to the center (mirror surface) between the radiation elements 32-1 and 32-2. The aluminum inner element 32a and the brass feed line 36 are connected via zinc plating or a plate to prevent electrolytic corrosion.
　図１１及び１２に戻り、放射素子３２－１、３２－２と給電線路３６とがなす概観がＨ型であるため、これらをＨ型折返しアンテナと呼ぶことにする。放射素子３２－３、３２－４も同様にＨ型折返しアンテナを構成する。この２つのＨ型折返しアンテナは、前述の放射素子３２－１と３２－２との鏡映面と垂直な面において面対称となるようスタックされ、その結果、放射素子３２－１～３２－４は同一面上に並ぶことになる。反射板３１は、その同一面と平行に設けられ、反射板３１の中心は、放射素子３２－１～３２－４の配列の中心と略等しい。 11 and 12, since the appearance formed by the radiating elements 32-1 and 32-2 and the feed line 36 is H-type, these will be referred to as H-type folded antennas. Similarly, the radiating elements 32-3 and 32-4 constitute an H-shaped folded antenna. These two H-shaped folded antennas are stacked so as to be plane-symmetrical in a plane perpendicular to the mirror surface of the above-described radiating elements 32-1 and 32-2. As a result, the radiating elements 32-1 to 32-4 are stacked. Are lined up on the same plane. The reflection plate 31 is provided in parallel with the same surface, and the center of the reflection plate 31 is substantially equal to the center of the arrangement of the radiation elements 32-1 to 32-4.
　反射板３１の幅（短辺の長さ）Ａは、放射素子３２－１と３２－２との間隔（Ｈ型折返しアンテナの幅）ｆよりも広く、長さＢは、スタック間隔Ｃと放射素子長ｄの和よりも長い。すなわち反射板３１は、放射素子３２－１～３２－４の配列の外形寸法（外側寸法）よりも大きい。また反射板３１の長辺には、放射素子３２が設けられる面とは反対側（すなわちアンテナ装置の放射指向における後方）へ折り返された折返し部３１ａが設けられる。折り返しの角度は任意であるが、本例では９０度である。折返し部３１ａは、反射板３１同様に後方への放射（回り込み）を抑えるように働く。反射板３１の幅（短辺の長さ）Ａと折返し部３１ａの長さＤは、調整可能であり、用途に応じて交換可能な部材により、幅Ａや長さＤを継ぎ足しても良い。 The width (short side length) A of the reflector 31 is wider than the distance (width of the H-type folded antenna) f between the radiating elements 32-1 and 32-2, and the length B is radiated from the stack distance C. It is longer than the sum of the element lengths d. That is, the reflecting plate 31 is larger than the outer dimension (outer dimension) of the arrangement of the radiating elements 32-1 to 32-4. The long side of the reflector 31 is provided with a folded portion 31a that is folded back to the side opposite to the surface on which the radiating element 32 is provided (that is, rearward in the radiation direction of the antenna device). The turning angle is arbitrary, but is 90 degrees in this example. The folded portion 31 a works to suppress the backward radiation (wraparound) as with the reflector 31. The width (short side length) A of the reflecting plate 31 and the length D of the folded portion 31a can be adjusted, and the width A and the length D may be added by a replaceable member depending on the application.
　給電線路３４は、真鍮製の伝送導体３４－ａとストリップ線路アース板３４－ｂとで構成されるマイクロストリップ線路であり、その両端が、２つのＨ型折返しアンテナのそれぞれの給電線路３６の中央と接続され、その略中央部が、給電部３３に接続される。これにより給電部３３からの電力は、給電線路３４の中央で２分され、更に給電線路３６の中央と接続される際にそれぞれ２分され、各放射素子３２に供給される。 The feed line 34 is a microstrip line composed of a transmission conductor 34-a made of brass and a strip line ground plate 34-b, and both ends thereof are the centers of the feed lines 36 of the two H-type folded antennas. The substantially central portion thereof is connected to the power feeding unit 33. As a result, the electric power from the power supply unit 33 is divided into two at the center of the power supply line 34, and further divided into two when being connected to the center of the power supply line 36, and supplied to each radiation element 32.
　給電線路３４は、ストリップ線路アース板３４－ｂ側が反射板３１に向かい合うように設けられ、ストリップ線路アース板３４－ｂは、その両端部において反射板３１と４個の真鍮製のスペーサ３５により支持され、電気的にも接続される。伝送導体３４－ａは、各所においてストリップ線路アース板３４－ｂから絶縁性スペーサ（不図示）を介して支えられる。図１１及び図１２では、Ｈ型折返しアンテナは、この給電線路３４の端部でのみ支えられているが、反射板３１から複数の絶縁性スペーサにより直接支えるようにしても良い。また給電線路３４は、トリプレート線路等の各種の不平衡線路と置換できる。 The feed line 34 is provided so that the strip line ground plate 34-b side faces the reflector 31. The strip line ground plate 34-b is supported by the reflector 31 and four brass spacers 35 at both ends thereof. And is also electrically connected. The transmission conductor 34-a is supported at various places from the stripline ground plate 34-b via an insulating spacer (not shown). In FIGS. 11 and 12, the H-shaped folded antenna is supported only at the end of the feed line 34, but may be supported directly from the reflector 31 by a plurality of insulating spacers. The feed line 34 can be replaced with various unbalanced lines such as a triplate line.
　ここで、アンテナ装置３０の具体的な寸法例は、次のように表される。アンテナ装置３０の通信周波数帯における中心周波数ｆｃの波長をλｃと表した場合、反射板３１の横幅Ａは０．３λｃ、反射板３１の長さＢは１．２３λｃ、スタック間隔（２つのＨ型折返しアンテナの中心間の距離）Ｃは０．５５λｃ、反射板３１からの突出の最大高さＨは０．０９λｃ、内側素子３２ａの幅ａは０．０６λｃ、内側素子３２ａと外側素子３２ｂとの間隔ｂは０．０６λｃ、外側素子３２ｂの幅ｃは０．０４λｃ、放射素子長ｄは０．４３λｃ、外側素子３２ｂのチャネルの深さｅは０．０６λｃ、放射素子間隔ｆは０．１０λｃに設定される。 Here, a specific dimension example of the antenna device 30 is expressed as follows. When the wavelength of the center frequency fc in the communication frequency band of the antenna device 30 is expressed as λc, the lateral width A of the reflector 31 is 0.3λc, the length B of the reflector 31 is 1.23λc, and the stack interval (two H-types) The distance between the centers of the folded antennas) C is 0.55λc, the maximum height H of the protrusion from the reflector 31 is 0.09λc, the width a of the inner element 32a is 0.06λc, and the inner element 32a and the outer element 32b The distance b is 0.06λc, the width c of the outer element 32b is 0.04λc, the radiating element length d is 0.43λc, the channel depth e of the outer element 32b is 0.06λc, and the radiating element interval f is 0.10λc. Is set.
　図１４は、上記のように設定した場合のアンテナ装置３０のＶＳＷＲ特性であり、横軸に周波数［ＭＨｚ］をとり、縦軸にＶＳＷＲをとって示した。図１４から、ＶＳＷＲ特性は、１７８ＭＨｚから１９３ＭＨｚに亘って１．５以下となり比帯域幅８％が得られる。また、垂直面指向性を図１５に、水平面指向性を図１６に示す。図１５及び図１６において、１点線は１７９ＭＨｚ、実線は１８４ＭＨｚ、二点鎖線は１８９ＭＨｚの場合を示している。 FIG. 14 shows the VSWR characteristics of the antenna device 30 set as described above, with the horizontal axis representing the frequency [MHz] and the vertical axis representing VSWR. From FIG. 14, the VSWR characteristic becomes 1.5 or less from 178 MHz to 193 MHz, and a specific bandwidth of 8% is obtained. Further, the vertical plane directivity is shown in FIG. 15, and the horizontal plane directivity is shown in FIG. 15 and FIG. 16, the one-dot line indicates a case of 179 MHz, the solid line indicates a case of 184 MHz, and the two-dot chain line indicates a case of 189 MHz.
　図１７は上記アンテナ装置３０の給電部３３におけるインピーダンス特性を示したもので、横軸に周波数［ＭＨｚ］をとり、縦軸にインピーダンス［Ω］をとり、実部を実線で、虚部を破線で示した。このインピーダンス特性は、図１７から明らかなように、１７９～１９２ＭＨｚ付近まで略一定のインピーダンス（抵抗値）が得られている。 FIG. 17 shows impedance characteristics in the power feeding section 33 of the antenna device 30. The horizontal axis represents frequency [MHz], the vertical axis represents impedance [Ω], the real part is a solid line, and the imaginary part is a broken line. It showed in. As is apparent from FIG. 17, this impedance characteristic has a substantially constant impedance (resistance value) from 179 to 192 MHz.
　本例では図１１及び１２に示したように、外側素子３２ｂの左右両端を折り曲げて溝状の形状にすることにより、反射板３１からの放射素子３２の最大高さＨを０．０９λｃと低く設定しても、広帯域特性を維持することができる。 In this example, as shown in FIGS. 11 and 12, the maximum height H of the radiating element 32 from the reflector 31 is as low as 0.09λc by bending the left and right ends of the outer element 32b into a groove shape. Even if it is set, the broadband characteristics can be maintained.
　図１８に、実施例５に係るアンテナ装置の３面図を示す。このアンテナ装置３０Ａは、給電線路３４、３６を、放射素子３２の中心と同一面から、より反射板３１に近づけた点、反射板の中央からずらされた給電部３３を給電線路３４の中央に接続する新たな給電線路３７を備えた点、及びカバー３８を設けた点で実施例４と異なる。 FIG. 18 is a three-side view of the antenna device according to the fifth embodiment. The antenna device 30 </ b> A is configured so that the feed lines 34 and 36 are closer to the reflector 31 from the same plane as the center of the radiating element 32, and the feed unit 33 shifted from the center of the reflector is placed at the center of the feed line 34. The difference from the fourth embodiment is that a new feed line 37 to be connected and a cover 38 are provided.
　本例の給電線路３６’は、放射素子３２の給電点から反射板３１へ向かって下りた後、実施例４の給電線路３６と同様に反射板３１に平行な線路となる。本例の給電線路３４’は、給電線路３６’と同じ反射板３１からの距離に保たれている点以外は、実施例４の給電線路３４と同じである。 The feed line 36 ′ of this example is a line parallel to the reflector 31 like the feed line 36 of the fourth embodiment after descending from the feed point of the radiating element 32 toward the reflector 31. The feed line 34 ′ of this example is the same as the feed line 34 of Example 4 except that the feed line 34 ′ is maintained at the same distance from the reflector 31 as the feed line 36 ′.
　カバー３８は、ＦＲＰ（ファイバ強化プラスチック）等の絶縁性の素材であり、底辺が反射板３１に対応する台形状の断面の内部空間を有する。カバー３８の周囲の縁は、台形の底辺と同一平面をなして外側に張り出し、その縁においてボルトにより防水パッキンと共締めして反射板３１に固定される。本例ではカバー３８の幅及び長さは、反射板３１の幅Ａ及び長さＢとそれぞれ略同一である。Ｈ型折返しアンテナや給電線路等は、反射板３１とカバー３８とで閉ざされた空間に収納され、特に、カバー３８の角（台形の鈍角）が、Ｈ型折返しアンテナの外側素子３２ｂの端部付近に位置するようになっている。 The cover 38 is an insulating material such as FRP (fiber reinforced plastic), and has a trapezoidal cross-section internal space whose bottom corresponds to the reflector 31. The peripheral edge of the cover 38 projects outwardly in the same plane as the trapezoid base, and is fixed to the reflecting plate 31 at the edge together with the waterproof packing with bolts. In this example, the width and length of the cover 38 are substantially the same as the width A and length B of the reflecting plate 31, respectively. The H-shaped folded antenna, the feed line, and the like are housed in a space closed by the reflector 31 and the cover 38. In particular, the corner of the cover 38 (the obtuse angle of the trapezoid) is the end of the outer element 32b of the H-shaped folded antenna. It is located in the vicinity.
　図１９に、実施例５に係るアンテナ装置の給電線路３７の３面図を示す。給電線路３７は、平板上の中心導体を、それに平行な２枚のアース板で挟んだ構造のトリプレート線路であり、中心導体の反射板３１からの高さは、給電線路３４’の伝送導体３４’－ａと同じである。給電線路３７は、給電線路３４’の中央に接続し、側方に向かった後、直角に折れ曲がって、反射板３１を貫通して設けられた接栓の直上まで伸びている。本例の給電線路３７はその一部において、本アンテナ装置の接栓における公称インピーダンス（５０Ω）と異なる特性インピーダンスを有しており、静電容量を給電部３３に並列に装荷したように作用する。 FIG. 19 shows a three-sided view of the feeder line 37 of the antenna device according to the fifth embodiment. The feed line 37 is a triplate line having a structure in which a central conductor on a flat plate is sandwiched between two parallel ground plates, and the height of the center conductor from the reflector 31 is the transmission conductor of the feed line 34 '. This is the same as 34'-a. The feed line 37 is connected to the center of the feed line 34 ′, is directed to the side, then bends at a right angle, and extends to a position directly above the plug provided through the reflector 31. A part of the feed line 37 of this example has a characteristic impedance different from the nominal impedance (50Ω) of the plug of the antenna device, and acts as if the electrostatic capacity was loaded in parallel with the feed part 33. .
　本例によれば、最大高さＨが低いため、カバー３８の高さも低くでき、風圧の受けにくさや外観を改善することができる。また、給電線路３４’や３６’は、反射板３１からの高さが低くなったものの、反射板３１とは別体に構成されており、カバー３８内に侵入し反射板を伝ってくる、或いはカバー３８内で結露した水分による腐食の影響を受けにくくできる効果は保たれる。給電線路３４’や３６’が放射素子３２から離れたことで、放射素子との結合が減り、アンテナの設計が容易になることが期待できる。 According to this example, since the maximum height H is low, the height of the cover 38 can be reduced, and the difficulty of receiving wind pressure and the appearance can be improved. Further, although the feed lines 34 ′ and 36 ′ have a lower height from the reflection plate 31, they are configured separately from the reflection plate 31 and enter the cover 38 and travel through the reflection plate. Alternatively, the effect of being less susceptible to corrosion due to moisture condensed in the cover 38 is maintained. Since the feed lines 34 ′ and 36 ′ are separated from the radiating element 32, it can be expected that the coupling with the radiating element is reduced and the antenna design is facilitated.
　図２０に、実施例６に係るアンテナ装置を示す。アンテナ装置３０Ｂの放射素子３２は、一体の部材を折り曲げ等して内側素子３２ａと外側素子３２ｂとを形成してなるものである。また、上記同様に、アンテナ装置３０ＢのＶＳＷＲ特性を図２１に示し、垂直面指向性を図２２に、水平面指向性を図２３に、インピーダンス特性を図２４に示す。 FIG. 20 shows an antenna apparatus according to the sixth embodiment. The radiating element 32 of the antenna device 30B is formed by bending an integral member to form an inner element 32a and an outer element 32b. Similarly to the above, FIG. 21 shows the VSWR characteristics of the antenna device 30B, FIG. 22 shows the vertical plane directivity, FIG. 23 shows the horizontal plane directivity, and FIG. 24 shows the impedance characteristics.
　図２５に、実施例７に係るアンテナ装置を示す。アンテナ装置３０Ｃは、放射素子３２の外側素子３２ｂを、外側ではなく反射板３１に向け、内側素子３２ａ及び外側素子３２ｂの幅方向が反射板３１と平行になるよう配置したものである。 FIG. 25 shows an antenna apparatus according to the seventh embodiment. In the antenna device 30 </ b> C, the outer element 32 b of the radiating element 32 is arranged not toward the outer side but toward the reflecting plate 31 so that the width direction of the inner element 32 a and the outer element 32 b is parallel to the reflecting plate 31.
　ここで、本発明の実施例に係るアンテナ装置との対比のため、従来例のアンテナ装置の特性を示す。図２６は、従来例１のアンテナ装置の構成を示す図である。ダイポール素子を２段スタックにして構成する場合、半値幅１２０°の指向性を得るには、一例として、反射板の幅Ａを約０．６２λ、長さＢを約２．４８λとし、その反射板上の高さＨ：０．２５～０．３０λにダイポールアンテナを設ける。 Here, for comparison with the antenna device according to the embodiment of the present invention, characteristics of the antenna device of the conventional example are shown. FIG. 26 is a diagram illustrating the configuration of the antenna device of the first conventional example. When a dipole element is configured in a two-stage stack, in order to obtain a directivity with a half-value width of 120 °, for example, the width A of the reflector is set to about 0.62λ, and the length B is set to about 2.48λ. A dipole antenna is provided at a height H on the plate of 0.25 to 0.30λ.
　図２６の従来例３のアンテナ装置の、ＶＳＷＲ特性を図２７に、垂直面指向性を図２８に、水平面指向性を図２９に、インピーダンス特性を図３０に示す。なお、従来例３のアンテナ装置では、放射素子として平板状のダイポールを用い、そのスタック間隔Ｃは０．５５λｃ、放射素子長Ｄは０．４７λｃ、放射素子と反射板の間隔Ｈは０．３０λｃである。大きな反射板のサイズおよび反射板からの突出が許容されるなら、広帯域のセクタアンテナを構成することは従来から可能である。 FIG. 27 shows the VSWR characteristics, FIG. 28 shows the vertical plane directivity, FIG. 29 shows the horizontal plane directivity, and FIG. 30 shows the impedance characteristics of the antenna device of Conventional Example 3 shown in FIG. In the antenna device of Conventional Example 3, a flat dipole is used as the radiating element, the stack distance C is 0.55λc, the radiating element length D is 0.47λc, and the distance H between the radiating element and the reflecting plate is 0.30λc. It is. If a large reflector size and protrusion from the reflector are allowed, it is possible to construct a broadband sector antenna conventionally.
　また、従来例４のアンテナ構成を図３１に示す。図３２に従来例４のアンテナ装置のＶＳＷＲ特性、図３３に垂直面指向性、図３４に水平面指向性、図３５にインピーダンス特性を示す。従来例４のアンテナ構成は、従来例３に比べ反射板からの間隔を０．０９λｃと短くしたものであり、そのことにより図３０に示すようにＶＳＷＲ特性が急激に悪化している。つまり、反射板と放射素子（の中心）との距離が０．１λ以下の場合には、放射素子が低インピーダンスとなり整合が困難になる。 The antenna configuration of Conventional Example 4 is shown in FIG. FIG. 32 shows the VSWR characteristics of the antenna device of Conventional Example 4, FIG. 33 shows the vertical plane directivity, FIG. 34 shows the horizontal plane directivity, and FIG. 35 shows the impedance characteristics. In the antenna configuration of Conventional Example 4, the distance from the reflecting plate is shortened to 0.09λc as compared to Conventional Example 3, and as a result, the VSWR characteristics are rapidly deteriorated as shown in FIG. That is, when the distance between the reflector and the radiating element (the center thereof) is 0.1λ or less, the radiating element has a low impedance, making matching difficult.
　これに対し、本実施形態では、従来例３、２のようなダイポールアンテナを、図１１に示したようなＨ型の折返しアンテナに置き換えることにより、最大突出高さＨを０．０９λｃに固定し、反射板３１を横幅約０．３λｃ、長さ約１．２３λｃのように小型化して、且つ、指向性、ＶＳＷＲも広帯域特性とすることができる。 On the other hand, in the present embodiment, the maximum protrusion height H is fixed to 0.09λc by replacing the dipole antenna as in the conventional examples 3 and 2 with an H-shaped folded antenna as shown in FIG. The reflector 31 can be downsized to have a lateral width of about 0.3λc and a length of about 1.23λc, and the directivity and VSWR can be wideband characteristics.
　なお、上記各実施例に示した寸法は、比帯域幅（例えば８％）と同程度の範囲内で、変更できる可能性がある。また、放射素子３２はその中央で給電するものに限らず、内側素子３２ａの長さを異ならせても良い。また放射素子３２と反射板３１の間の空間に空気以外の誘電体を充填し、更なる小型化を図ってもよい。また３面以上の多面合成を行って、セクタアンテナではなく無指向性アンテナを実現してもよい。 Note that the dimensions shown in the above embodiments may be changed within the same range as the specific bandwidth (for example, 8%). Further, the radiating element 32 is not limited to being fed at the center, and the length of the inner element 32a may be varied. Further, the space between the radiating element 32 and the reflecting plate 31 may be filled with a dielectric other than air to further reduce the size. Further, non-directional antennas may be realized instead of sector antennas by performing polyhedral synthesis of three or more planes.
　すなわち、この発明は、上記実施形態そのままに限定されるものではなく、実施段階ではその要旨を逸脱しない範囲で構成要素を変形して具体化できる。また、上記実施形態に開示されている複数の構成要素の適宜な組み合せにより種々の発明を形成できる。 That is, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment.

Claims (7)

  1. 　略方形状に形成された反射板と、
    　前記反射板の前面に所定の間隔を保って設けられるアンテナ素子と、
    　前記反射板の両側部に設けられる２つの折曲部と
    を具備し、
    　前記折曲部は、前記側部の後方に前記アンテナ素子の偏波方向と同一方向に設けられる棒状導体の垂直素子と、前記垂直素子を複数箇所において前記反射板と結合する水平素子とを有して、枠形状に形成されるアンテナ装置。     A reflector formed in a substantially rectangular shape;
    An antenna element provided at a predetermined interval on the front surface of the reflector;
    Comprising two bent portions provided on both sides of the reflector,
    The bent portion includes a vertical element of a rod-like conductor provided behind the side portion in the same direction as the polarization direction of the antenna element, and a horizontal element that couples the vertical element to the reflector at a plurality of locations. An antenna device formed into a frame shape.
  2. 　前記折曲部は、前記垂直素子の長さを前記反射板の前記偏波方向の長さと略等しくし、前記前記水平素子を絶縁部材により形成し、該絶縁部材により前記垂直素子を保持する請求項１に記載のアンテナ装置。 The bent portion has a length of the vertical element substantially equal to a length of the reflection plate in the polarization direction, the horizontal element is formed of an insulating member, and the vertical element is held by the insulating member. Item 2. The antenna device according to Item 1.
  3. 　前記反射板と前記垂直素子との間隔を、０．１５５λ（λは前記アンテナ装置の使用帯域内の周波数における波長）とする請求項１に記載のアンテナ装置。 The antenna device according to claim 1, wherein an interval between the reflecting plate and the vertical element is 0.155λ (λ is a wavelength at a frequency within a use band of the antenna device).
  4. 　前記請求項１に記載のアンテナ装置を多段に構成するアンテナ装置。 An antenna device comprising the antenna device according to claim 1 in multiple stages.
  5. 　所定の平面上で、上下対称及び左右対称に配置された４個の折返しダイポールアンテナと、
    　前記所定の平面と水平で、前記４個の折返しダイポールアンテナの配置の外側寸法よりも大きな平板状の反射板と、
    　前記反射板の前面中央に沿って前記反射板とは別体に設けられ、前記放射素子のそれぞれに給電部からの給電信号を供給する給電線路と
    を具備し、
    　前記折返しダイポールアンテナのそれぞれは、ダイポールアンテナ様の１対の素子と、前記１対の素子の両端を直線状につなぐ略λ／２（λは使用周波数における波長）長の折返し素子を備え、前記折返し素子は、溝状の断面を押し出た形状をなし、該溝の底の外側において前記１対の素子と対向し、前記溝の幅は、前記１対の素子の幅よりも広く形成され、
    　前記反射板からの前記折返し素子の最大距離が、０．１λ以下であるアンテナ装置。     Four folded dipole antennas arranged symmetrically vertically and horizontally on a predetermined plane;
    A flat reflector that is horizontal to the predetermined plane and larger than the outer dimension of the arrangement of the four folded dipole antennas;
    Provided separately from the reflection plate along the center of the front surface of the reflection plate, comprising a power supply line that supplies a power supply signal from a power supply unit to each of the radiating elements,
    Each of the folded dipole antennas includes a pair of elements such as a dipole antenna and a folded element having a length of approximately λ / 2 (λ is a wavelength at a used frequency) that connects both ends of the pair of elements in a straight line. The folded element is formed by extruding a groove-shaped cross section, and is opposed to the pair of elements outside the bottom of the groove, and the width of the groove is wider than the width of the pair of elements. ,
    An antenna device in which a maximum distance of the folded element from the reflecting plate is 0.1λ or less.
  6. 　前記給電線路の少なくとも一部は、不平衡線路で構成され、該不平衡線路のアース側と前記反射板との間に複数の金属製のスペーサを有し、
    　前記反射板は、長方形であり、該長方形の長辺において後方へ折り返された折曲部を有し、該折曲部の一部は着脱可能に構成される請求項５記載のアンテナ装置。     At least a part of the feeder line is composed of an unbalanced line, and has a plurality of metal spacers between the ground side of the unbalanced line and the reflector.
    The antenna device according to claim 5, wherein the reflection plate is rectangular, has a bent portion that is folded backward on a long side of the rectangle, and a part of the bent portion is configured to be detachable.
  7. 　前記使用周波数はＶＨＦであり、
    　前記反射板の前面に、該反射板と共働して、前記４個の折返しダイポールアンテナと前記給電線路とを収納するカバーを更に有し、該カバーは、底辺が反射板に対応し、鈍角が外側素子の端部付近に位置するような台形状の断面を有する請求項５記載のアンテナ装置。     The frequency used is VHF,
    The front surface of the reflector further includes a cover that accommodates the four folded dipole antennas and the feed line in cooperation with the reflector, and the cover has a bottom corresponding to the reflector and an obtuse angle. The antenna device according to claim 5, wherein the antenna device has a trapezoidal cross section that is positioned near the end of the outer element.
PCT/JP2009/070780 2009-04-07 2009-12-11 Antenna device WO2010116570A1 (en)

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JP2009093266A JP2010245892A (en) 2009-04-07 2009-04-07 Antenna device
JP2009-093266 2009-04-07
JP2009-278824 2009-12-08
JP2009278824A JP2011124653A (en) 2009-12-08 2009-12-08 Antenna device

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6326006A (en) * 1986-07-18 1988-02-03 Tech Res & Dev Inst Of Japan Def Agency Array antenna with reflection plate
JP2004023797A (en) * 2002-06-19 2004-01-22 Andrew Corp Folded dipole antenna
JP2004289473A (en) * 2003-03-20 2004-10-14 Hitachi Cable Ltd Substrate type antenna
JP2005045449A (en) * 2003-07-25 2005-02-17 Hitachi Cable Ltd Polarization diversity antenna
JP2007060062A (en) * 2005-08-23 2007-03-08 Nippon Dengyo Kosaku Co Ltd Polarization common antenna

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6326006A (en) * 1986-07-18 1988-02-03 Tech Res & Dev Inst Of Japan Def Agency Array antenna with reflection plate
JP2004023797A (en) * 2002-06-19 2004-01-22 Andrew Corp Folded dipole antenna
JP2004289473A (en) * 2003-03-20 2004-10-14 Hitachi Cable Ltd Substrate type antenna
JP2005045449A (en) * 2003-07-25 2005-02-17 Hitachi Cable Ltd Polarization diversity antenna
JP2007060062A (en) * 2005-08-23 2007-03-08 Nippon Dengyo Kosaku Co Ltd Polarization common antenna

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