JP4310687B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device, and more particularly, to an antenna device that has a high degree of freedom and is miniaturized to realize broadband characteristics.

  As an example of a conventional plate-shaped broadband antenna, an antenna device using a semicircular conductor plate is shown in the literature, R.M. Taylor., “A Brodband Omnidirectional Antenna,”. An example of the configuration is shown in FIGS.

  FIG. 1A shows an antenna device provided with semi-elliptical radiation plates (conductor plates) 1a and 1b, and FIG. 1B shows an antenna device provided with semi-circular radiation plates 1a and 1b. The radiation plates 1a and 1b are arranged so that the vertices 2a and 2b of the semicircular arcs face each other. The power feeding unit 3 is provided between the apexes 2a and 2b and is fed from a coaxial power feeding cable (not shown).

  FIG. 2 shows an antenna device provided with radiation plates 1a and 1b having an isosceles triangle shape. The radiation plates 1a and 1b are arranged so that the apexes 2a and 2b face each other, and the apex angle is increased by 90 degrees or more. The power feeding unit 3 is provided between the apexes 2a and 2b and is fed from a coaxial power feeding cable (not shown).

  Here, as shown in FIG. 3, the VSWR (Voltage Standing Wave Ratio) characteristic of the antenna device when the radius r of the semicircular radiation plates 1a and 1b is 0.25λ = 25 mm is shown in FIG. Shown in In FIG. 4, the vertical axis represents VSWR characteristics, and the horizontal axis represents frequency (GHz). One scale on the horizontal axis is 800 MHz. In general, since the band where VSWR ≦ 2.0 is used, it is understood that the lowest frequency that satisfies this condition is about 1.7 GHz and has wideband characteristics.

  By the way, in order to realize an antenna device having broadband characteristics, it is necessary to increase the surface shape according to the lowest frequency. The radiation plates 1a and 1b shown in FIGS. 1 and 2 are different in shape, but both have a structure in which power is supplied by bringing apexes including a center line of a symmetrical plane shape close to each other. This is because the geometrical area similarity ratio corresponding to each wavelength can be easily obtained with the power feeding unit 3 (vertex) as the origin. That is, in FIG. 1 to FIG. 3, the antenna device having a small radiation plate 1a, 1b in the shaded portion and the antenna device having a large radiation plate 1a, 1b including the shaded portion are electromagnetic fields. Are similar to each other, and the two large and small antenna devices have exactly the same characteristics.

  As described above, the antenna device having a similar structure is called an electromagnetic field similarity theory, and it is understood that the antenna device has a characteristic irrelevant to the frequency (see, for example, Non-Patent Document 1).

  FIG. 5 includes a semicircular radiating plate 1 that is one radiating element of the bipolar (dipole) antenna device shown in FIG. 1 and a planar conductor ground plate 11 that acts as an electric image plane. 1 shows a monopole type (monopole type) antenna device that operates equivalently to the antenna device shown. The semicircular radiating plate 1 is vertically arranged so that the arc apex 2 thereof is close to and opposed to the planar conductor ground plane 11. The power feeding unit 3 is provided between the arc apex 2 or between the arc apex 2 and the planar conductor ground plane 11, and is fed from the coaxial power supply cable 12. The planar conductor ground plane 11 forms an electric image of the radiation plate 1 on the back surface when the surface on which the radiation plate 1 is disposed is the front surface, and operates equivalent to the antenna device shown in FIG.

Shinji Matsumoto, Introduction to Radio Engineering, p120-124

  As shown in FIGS. 1 and 2, the dipole antenna device having a wideband characteristic is configured such that the shape of the radiation plates 1a and 1b is a symmetrical plane shape with at least one vertex as the origin, and the radiation plates 1a, 1b, It was necessary to feed the central points with the apexes 2a and 2b of 1b close to each other.

  In addition, because of the structure of the antenna device, the antenna device has a radiation surface structure that geometrically expands in the horizontal direction (lateral direction in the plane of FIG. 1 to FIG. 3) as the distance from the feeding unit 3 increases. There was a problem of increasing the size.

  Further, as shown in FIG. 5, the monopole antenna device having a wide band characteristic has a high center of gravity when mounted on a flat conductor ground plane 11 such as a vehicle body, and therefore, structural and hydrodynamic characteristics are increased. However, there is a problem that the shape becomes unstable and the shape becomes less flexible.

  The present invention has been made in view of such a situation, and makes it possible to realize broadband characteristics with a highly flexible shape. Moreover, it enables it to reduce in size according to a use application.

The antenna device of the present invention is disposed in proximity so that the first radiation plate and the second radiation plate face each other, and a gap is formed between the first radiation plate and the second radiation plate disposed in proximity to each other, A power feeding unit is provided at a position near the opening end of the gap and in a range represented by s / 3 ± 10% when the length of the gap in the longitudinal direction is s, and is separated from the power feeding unit. The width of the gap at the opening end close to the power feeding portion is larger than the width of the gap at the opening end, and the width of the gap at the position where the power feeding portion is provided is 0.1 to 0.5 mm. The first radiating plate and the second radiating plate are formed in a tapered shape from the power feeding portion toward both opening ends so as to have a width of.

  When the length in the longitudinal direction of the gap formed between the first radiation plate and the second radiation plate is s and the maximum spread width of the first radiation plate is k, the aspect ratio m is s / 2k. And the value can be in the range of 0.3 <m <0.7.

In the present invention, the first radiation plate and the second radiation plate are disposed close to each other so that a gap is formed between the first radiation plate and the second radiation plate that are disposed close to each other. A power feeding part is provided at a position near the opening end and in a range represented by s / 3 ± 10%, where s is the length in the longitudinal direction of the gap, and the opening is separated from the power feeding part. The width of the gap at the opening end close to the power feeding part is wider than the width of the gap at the end, and the width of the gap at the position where the power feeding part is provided is 0.1 to 0.5 mm. Thus, the first radiation plate and the second radiation plate are tapered from the feeding portion toward both opening ends.

According to the present invention , wideband characteristics can be realized. In particular, broadband characteristics can be realized with a highly flexible shape.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 6 is a diagram showing an example of the basic configuration of the wideband antenna apparatus according to the present invention. In addition, the same code | symbol is attached | subjected to the part corresponding to the past, and the description is abbreviate | omitted suitably. Each of the square-shaped radiation plates 1a and 1b has, for example, a side of 25 mm, and a 1 mm slot-shaped gap (gap) 21 between the radiation plates 1a and 1b (a region indicated by a shadow in FIG. 6). Are arranged close to each other. The power feeding units 3-1 to 3-3 are provided at one end of the slot-shaped gap 21, and are fed from a coaxial power feeding cable (not shown).

  The radiation plates 1a and 1b are made of a material such as aluminum or copper, and the shape thereof may be either thin or plate-like.

  The width (slot width) of the gap 21 is generally intended for impedance matching means by changing the degree of coupling between the radiation plates 1a and 1b. The power feeding units 3-1 to 3-3 (hereinafter simply referred to as the power feeding unit 3 when the power feeding units 3-1 to 3-3 do not need to be individually distinguished) are predetermined positions in the slot longitudinal direction of the gap 21. However, it is set to a position where the VSWR is almost low over the entire required bandwidth.

  Here, the predetermined position of the gap 21 in the longitudinal direction of the slot will be described. First, in the gap 21 of the antenna device of FIG. 6, the power feeding unit 3 is slid in the slot longitudinal direction (vertical direction on the paper surface of FIG. 6), and the VSWR characteristics at each position are measured.

  FIG. 7 shows the VSWR characteristics in the case of the power feeding unit 3-1 (approximately the center position), and FIG. 8 shows the VSWR characteristics in the case of the power feeding units 3-2 and 3-3. 7 and 8, the vertical axis represents VSWR characteristics, and the horizontal axis represents frequency (GHz). One scale on the horizontal axis is 800 MHz.

  In the power feeding unit 3-1, as shown in FIG. 7, a VSWR characteristic of 1.9 is obtained at a frequency near 2 GHz (P1 in the figure), and a VSWR characteristic of 1.6 is obtained at a frequency near 4 GHz (P2 in the figure). As a result, a VSWR characteristic of 3.1 was obtained at a frequency around 6 GHz (P3 in the figure), and a VSWR characteristic of 4.4 was obtained at a frequency around 8 GHz (P4 in the figure).

  Further, as shown in FIG. 8, the power feeding units 3-2 and 3-3 obtain a VSWR characteristic of 1.9 at a frequency near 2 GHz (P11 in the figure), and a frequency around 4 GHz (P12 in the figure). A VSWR characteristic of 1.8 was obtained, a VSWR characteristic of 1.9 was obtained at a frequency around 6 GHz (P13 in the figure), and a VSWR characteristic of 2.2 was obtained around a frequency of 8 GHz (P14 in the figure).

  In general, since a band where VSWR ≦ 2.0 is used, a narrow band VSWR characteristic (FIG. 7) is obtained in the power feeding unit 3-1, and a wide band VSWR is obtained in the power feeding units 3-2 and 3-3. Characteristics (FIG. 8) are obtained. That is, it can be seen that broadband characteristics can be obtained at the positions of the power feeding units 3-2 and 3-3 provided near the open end of the gap 21 in the longitudinal direction of the slot. According to the experience of the present inventors, the power feeding units 3-2 and 3-3 are positioned 7 to 8 mm inside from the slot open end (the upper end or the lower end of the radiation plates 1 a and 1 b).

  As described above, the gap 21 is offset with respect to the center position of the entire length in the slot longitudinal direction (position of the power feeding part 3-1), and by using the power feeding parts 3-2 and 3-3 near the open end, a wide band is obtained. It becomes possible to obtain characteristics.

  The reason why the broadband characteristics can be obtained by the two power feeding units 3-2 and 3-3 is as follows. The VSWR characteristics in the power feeding units 3-2 and 3-3 (FIG. 8) are hardly seen in the vicinity of 1 to 4 GHz as compared with the VSWR characteristics in the power feeding unit 3-1 (FIG. 7). At frequencies higher than 4 GHz, the VSWR characteristics are greatly improved. That is, it can be seen that in the high frequency region, the similar structure of the triangular plate area is a position where the feeding portions 3-2 and 3-3 are easily formed.

  When the frequency is high, the wavelength is shorter than that of the antenna shape, and most of the current entered from the power feeding unit 3 is radiated into the air as radio waves before reaching the end of the antenna having a finite length. Therefore, the current at the end of the antenna is small and is not greatly affected by its shape. In other words, the presence or absence of the similar structure of the triangular plate area only in the vicinity of the power feeding unit 3 greatly affects the current input from the power feeding unit 3. Further, the shape of the terminal antenna away from the power feeding unit 3 determines a finite minimum frequency.

  From the above, among the power feeding units 3-1 to 3-3, the position where the similar structure of the triangular plate area is easily obtained in the vicinity of the power feeding unit is the slot opening end of the gap 21 (the upper end of the radiation plates 1 a and 1 b or It can be seen that it is close to the bottom edge.

  FIG. 9 schematically illustrates an example in which a similar structure with a triangular plate area is formed using the power feeding unit 3-2 as a base point.

  Currents that enter from the power feeding units 3-2 of the radiation plates 1a and 1b are transmitted in directions in which geometrical similarities indicated by arrows 31a and 31b are easily formed. Here, the radiation plate 1a is rotated 45 degrees clockwise around the power feeding part 3-2, and the radiation plate 1b is rotated 45 degrees counterclockwise around the power feeding part 3-2. The formed antenna device is configured in a symmetrical plane shape with a conventional vertex as an origin.

  FIG. 10 schematically illustrates an example in which a similar structure with a triangular plate area is formed with the power feeding unit 3-3 as a base point.

  Similarly to FIG. 9, the currents entered from the power feeding units 3-3 of the radiation plates 1a and 1b are transmitted in directions in which the geometrical similarity indicated by the arrows 31a and 31b can be easily formed. Here, the radiation plate 1a is rotated by 45 degrees counterclockwise about the power feeding unit 3-3, and the radiation plate 1b is rotated by 45 degrees clockwise about the power feeding unit 3-2. The antenna device is configured in a symmetrical plane shape with the conventional vertex as an origin.

  As shown in FIGS. 9 and 10, the antenna device formed by deploying the radiation plates 1a and 1b around the feeding portions 3-2 and 3-3 is an antenna device having a conventional apex structure. The expansion angle (the width of the slot-shaped gap 21) can optimize the antenna impedance or downsize the apparatus.

  From the above, the wideband antenna device which is the best mode for carrying out the present invention has the radiation plates 1a and 1b having slot-shaped gaps 21 having a predetermined width (hereinafter referred to as gap length as appropriate). The power supply unit 3 is provided at a predetermined position near the slot opening end of the gap 21 (the upper end or the lower end cut end of the radiation plate 1a, 1b). Of these, the characteristics on the high frequency side can be arbitrarily varied.

  Next, a specific example for realizing the principle of the broadband antenna apparatus shown in FIG. 6 will be described.

  FIG. 11 is a diagram illustrating a configuration example of an embodiment of a wideband antenna device. This wideband antenna apparatus includes ¼ circular radiation plates 1a and 1b.

  The radiation plates 1a and 1b are arranged close to each other with the symmetry line L as a boundary so as to have a gap 21 having a predetermined gap length. The gap 21 is formed so as to gradually increase in width toward the opening end (cut edge) with the feeding portion 3 as a base point. Further, the opening ends of the radiation plates 1a and 1b are appropriately tapered. The power feeding section 3 is provided at a predetermined position near the opening end of the gap 21 in the longitudinal direction of the slot (in the case of FIG. 11, the lower end of the radiation plates 1a and 1b), and is fed from a coaxial feeding cable (not shown). The

  In FIG. 11, s represents the total length of the gap 21 in the slot longitudinal direction. f represents the distance from the opening end of the gap 21 (in the case of FIG. 11, the lower end of the radiation plates 1a and 1b) to the power feeding unit 3, and s / 3 ± 10% is a recommended value. . k represents the maximum spread width in the horizontal direction (lateral direction in the drawing of FIG. 11) of the radiation plates 1a and 1b around the symmetry line L, and is λ / 4 length of the required minimum frequency. ga, gb, and gf represent the gap length of the gap 21.

  More specifically, as shown in FIG. 12 which is a partially enlarged view in the vicinity of the gap 21, ga is an opening end close to the power feeding unit 3 with the power feeding unit 3 as a base point (in the case of the example of FIG. 12, a radiation plate). This defines the gap length of the gap 21 at the lower end of 1a and 1b, and mainly affects the VSWR characteristics in a high frequency region. This is because the similar structure of the triangular plate area in the vicinity of the power feeding section 3 mainly strongly affects the radiation characteristics in the high frequency region.

  gb defines the gap length of the gap 21 at the opening end (in the example of FIG. 12, the top end of the radiation plates 1a and 1b) away from the power supply unit 3 with the power supply unit 3 as a base point. In other words, it defines a state in which the radiation plates 1a and 1b are unfolded by a predetermined rotation angle with the feeding unit 3 as an axis, and mainly affects the average characteristic of the antenna impedance.

  Then, the open end (cut) of the gap 21 formed in accordance with the definition of ga and gb is indicated by a one-dot broken line in FIG. 12 in order to prevent impedance mismatch at a specific frequency. Thus, the rounding process of the corners is performed in a tapered shape.

  gf defines the gap length of the gap 21 in the vicinity of the power feeding portion 3, preferably 2 mm or less, and a recommended value of 0.1 to 0.5 mm. As the antenna shape becomes larger, a better characteristic can be obtained at a higher frequency when the value of gf is smaller (that is, when the gap length is narrower).

  By providing the slot-shaped gap 21 formed between the radiation plates 1a and 1b in accordance with the above-mentioned regulations of ga, gb and gf, the degree of freedom with respect to the shape of the radiation plates 1a and 1b can be increased. A broadband antenna device can be formed with a high shape.

  The aspect ratio m represents a ratio with the maximum spread width k in the horizontal direction of the radiation plates 1a and 1b when the total slot length s is the vertical direction. As shown in FIG. 11, when the maximum spread width of the radiation plates 1a and 1b is 2k, the aspect ratio m is represented by s / 2k. The maximum spread width 2k determines the substantially lowest frequency and corresponds to a λ / 2 length.

  For example, when a disk having a radius of 25 mm is divided into two equal parts so as to form a slot-shaped gap 21, the aspect ratio m is 1 (= 50/50).

  Further, for example, when a square having a side of 25 mm is equally divided vertically or diagonally so as to form a slot-shaped gap 21, the aspect ratio m is 1 (= 25/25 (vertical division) = 25√2 / 25√2 (diagonal division)).

  Furthermore, for example, when an elliptical plate composed of the short axis s and the long axis 2k is divided on the short axis so as to form the slot-shaped gap 21, the aspect ratio m is s / 2k. On the other hand, when dividing on the long axis, the aspect ratio m is 2 k / s.

  Next, with reference to FIGS. 13 to 18, each VSWR characteristic when the aspect ratio m of the antenna device is changed will be further described. FIG. 13 shows a configuration example of the antenna device when the gap lengths ga, gb, and gf of the gap 21 are all 1 mm and the aspect ratio m is 1, 0.82, 0.67, 0.49, and 0.33, respectively. Yes. 14 to 18 show the VSWR characteristics of the antenna device at each aspect ratio shown in FIG. 14 to 18, the vertical axis represents VSWR characteristics, and the horizontal axis represents frequency (GHz). One scale on the horizontal axis is 800 MHz.

  FIG. 14 shows the VSWR characteristics of the antenna device when the aspect ratio m = 1. In the case of the example of FIG. 14, the VSWR characteristics near the lowest frequency are rapidly deteriorated, and ripples appear in the use band where VSWR ≦ 2.0. Therefore, when the aspect ratio m = 1, a narrow band VSWR characteristic is obtained.

  FIG. 15 shows the VSWR characteristics of the antenna device when the aspect ratio m = 0.82. In the case of the example of FIG. 15, the VSWR characteristics near the lowest frequency are rapidly deteriorated, as in FIG. Therefore, even when the aspect ratio m = 0.82, a narrow band VSWR characteristic can be obtained.

  FIG. 16 shows the VSWR characteristics of the antenna device when the aspect ratio is m = 0.67. In the case of the example of FIG. 16, the VSWR characteristics in the vicinity of the lowest frequency are considerably improved as compared with FIGS. Therefore, when the aspect ratio m = 0.67, a relatively wide band VSWR characteristic can be obtained.

  FIG. 17 shows the VSWR characteristics of the antenna device when the aspect ratio is m = 0.49. In the case of the example of FIG. 17, the minimum frequency where VSWR ≦ 2.0 is about 2.2 GHz, and good VSWR characteristics are obtained over the entire frequency. Therefore, when the aspect ratio is m = 0.49, a broadband VSWR characteristic is obtained.

  FIG. 18 shows the VSWR characteristics of the antenna device when the aspect ratio m = 0.33. In the case of the example of FIG. 18, the lowest frequency satisfying VSWR ≦ 2.0 is about 2.3 GHz, and good VSWR characteristics are obtained over the entire frequency as in FIG. Therefore, when the aspect ratio m = 0.33, a wide-band VSWR characteristic can be obtained.

  As shown in FIGS. 14 and 15, when the aspect ratio m is 0.82 or more (in practice, the aspect ratio m is actually 0.7 or more), the deterioration of the VSWR characteristics near the lowest frequency becomes remarkable. Alternatively, when the aspect ratio m is 0.7 or more, ripple symptoms appear and good broadband characteristics cannot be obtained. Furthermore, when the aspect ratio m is 0.3 or less, although not shown, good VSWR characteristics cannot be obtained over the entire frequency (that is, the value of the VSWR characteristics cannot be reduced).

  From the above, in the wideband antenna device in which the radiation plates 1a and 1b are arranged close to each other with the symmetry line L as a boundary, and the slot-shaped gap 21 is formed between the radiation plates 1a and 1b, It can be seen that the value of the ratio m affects the VSWR characteristics, and it is desirable to form the radiation plates 1a and 1b so as to fall within the range of 0.3 <m <0.7. However, even if it does not fall within the above range, wide band characteristics can be obtained by widening the slot-shaped gap 21 in a tapered shape from the power feeding section 3 so that gf << gb. . That is, by expanding the slot-shaped gap 21 in a taper shape so that gf << gb, a so-called symmetrical plane-shaped structure with one vertex as the origin is formed.

  Next, a broadband antenna device that satisfies the above-described conditions was actually designed, and its VSWR characteristics were measured. Hereinafter, some specific examples will be described. In the following description, it is assumed that λ = 100 mm and the structure of the gap 21 conforms to the structure shown in FIG.

  In FIG. 19, the total slot length s is 0.25λ, the maximum spread width 2k of the radiation plates 1a and 1b is 0.5λ (= 2 × 0.25λ), and the aspect ratio m is 0.5 (= 0.25λ / 0.5λ). The example of a structure of the wideband antenna apparatus provided with the radiation board 1a, 1b of 1/4 circle shape of the case is shown. FIG. 20 shows the VSWR characteristics of the antenna device shown in FIG. In the case of the example in FIG. 20, the lowest frequency satisfying VSWR ≦ 2.0 is about 2.05 GHz, and a wide band VSWR characteristic is obtained.

  In FIG. 21, the total slot length s is 0.20λ, the maximum spread width 2k of the radiation plates 1a and 1b is 0.5λ (= 2 × 0.25λ), and the aspect ratio m is 0.4 (= 0.20λ / 0.5λ). The example of a structure of the wideband antenna apparatus provided with the radiation board 1a, 1b of the 1/4 circle-shaped deformation | transformation of the case is shown. FIG. 22 shows the VSWR characteristics of the antenna device shown in FIG. In the case of the example of FIG. 22, the lowest frequency where VSWR ≦ 2.0 is about 2.1 GHz, and a wide band VSWR characteristic is obtained.

  In FIG. 23, the total slot length s is 0.25λ, the maximum spread width 2k of the radiation plates 1a and 1b is 0.5λ (= 2 × 0.25λ), and the aspect ratio m is 0.5 (= 0.25λ / 0.5λ). The example of a structure of the wideband antenna apparatus provided with the semi-elliptical radiation plates 1a and 1b in the case is shown. FIG. 24 shows the VSWR characteristics of the antenna device shown in FIG. In the case of the example of FIG. 24, the lowest frequency where VSWR ≦ 2.0 is about 2.1 GHz, and a wide band VSWR characteristic is obtained.

  In FIG. 25, the total slot length s is 0.20λ, the maximum spread width 2k of the radiation plates 1a and 1b is 0.5λ (= 2 × 0.25λ), and the aspect ratio m is 0.4 (= 0.20λ / 0.5λ). The example of a structure of the wideband antenna apparatus provided with the radiation plates 1a and 1b of the isosceles triangle shape in the case is shown. FIG. 26 shows the VSWR characteristics of the antenna device shown in FIG. In the case of the example of FIG. 26, the lowest frequency satisfying VSWR ≦ 2.0 is about 2.3 GHz, and a wide band VSWR characteristic is obtained.

  In FIG. 27, the total slot length s is 0.25λ, the maximum spread width 2k of the radiation plates 1a and 1b is 0.5λ (= 2 × 0.25λ), and the aspect ratio m is 0.5 (= 0.25λ / 0.5λ). The example of a structure of the wideband antenna apparatus provided with the square-shaped radiation | emission plates 1a and 1b in the case is shown. FIG. 28 shows the VSWR characteristics of the antenna device shown in FIG. In the case of the example in FIG. 28, the lowest frequency satisfying VSWR ≦ 2.0 is about 1.9 GHz, and a wide band VSWR characteristic is obtained.

  As described above, the wide-band antenna device of the present invention can be formed with a half area with respect to the design index of the conventional antenna device. Further, the lowest frequency that satisfies VSWR ≦ 2.0, which is the use band, is somewhat ripple-like in the conventional case, but is lower than the design index value and is about 1.7 GHz. On the other hand, in the case of the wideband antenna device of the present invention, as shown in FIGS. 19 to 28, by designing the aspect ratio m to 0.4 to 0.5, the ripple is suppressed and the minimum frequency is 2.05 to 2.3. Although it is about GHz, better VSWR characteristics can be obtained. When this is converted into a geometric shape ratio having equivalent characteristics, a wide-band antenna device that is actually downsized to 70 to 80 percent compared to the conventional one can be realized although the shape is somewhat larger.

  Next, in order to confirm the geometric shape ratio with respect to the operating frequency, as shown in FIG. 29, the shapes of the radiation plates 1a and 1b shown in FIG. 19 are designed to be 4.6 times larger, and the VSWR characteristics thereof. Was measured. In this antenna device, m = 0.41, 2k = 230 mm, gf = 0.1 mm, f = 30 mm, ga = 5 mm, gb = 8 mm, and further, the opening end of the gap 21 has a rounded corner rounding process. What has been done is used. FIG. 30 shows the VSWR characteristics of the antenna device shown in FIG. In the case of the example of FIG. 30, the design minimum frequency is 650 MHz, and the use band where VSWR ≦ 2.0 is 500 MHz to 9 GHz, and a wide band VSWR characteristic is obtained.

  As described above, the wideband antenna device of the present invention in which the radiation plates 1a and 1b having the same shape are arranged close to each other so as to have the slot-shaped gap 21 is a compact antenna device having excellent matching and relatively high flexibility. Can be configured. In addition, the band characteristics of the wideband antenna device of the present invention can achieve the band characteristics equivalent to the conventional one while realizing downsizing.

  Note that the above-described measurement result of the VSWR characteristic is a result of unbalanced power feeding by 50Ω coaxial, but it goes without saying that the same result can be obtained even by balanced power feeding.

  In the above description, the broadband antenna device in the case of the bipolar type (dipole type, λ / 2 type) has been described as an example. However, the present invention is not limited to this, and the single pole type (monopole type, λ / Of course, it is also possible to apply to 4 type).

  FIG. 31 is a diagram illustrating a configuration example of a single-pole type broadband antenna device. In the case of this example, the ¼ circular radiation plate 1 is disposed vertically on the planar conductor ground plane 11, and the external conductor of the feeder line (not shown) is grounded to the planar conductor ground plane 11, so that the electric image plane is directly below. The radiation plate 1 ′ formed as is capable of obtaining an operation equivalent to that of the radiation plate 1 b of the bipolar antenna device described above. The radiating plate 1 is disposed close to the planar conductor ground plane 11 so as to have a slot-shaped gap 21 having a predetermined gap length between the radiation plate 1 and the slot opening end of the gap 21. A power feeding unit 3 is provided at a predetermined position on the side.

  Thus, by arranging the radiation plate 1 close to the planar conductor ground plate 11 so as to have the gap 21 having a predetermined gap length, it is possible to achieve excellent matching and further reduce the size of the broadband antenna device. It becomes.

  Further, in the above description, the broadband antenna device configured by the radiation plates 1a and 1b having the same shape has been described as an example. However, the present invention is not limited thereto, and the radiation plate 1a and 1b having different shapes may be used. In addition, good band characteristics can be obtained.

  FIG. 32 shows a configuration example of the wideband antenna device when the radiation plate 1b is replaced with a radiation plate having a shape different from that of the radiation plate 1a. The radiation plates 1a and 1b are disposed close to each other so as to have a slot-shaped gap 21 having a predetermined gap length, and the power feeding unit 3 is provided at a predetermined position near the slot opening end of the gap 21. In the case of the example of FIG. 32, the radiation plate 1b is formed to have the same size as the overall length of the radiation plate 1a in the longitudinal direction of the slot, but the maximum spread width in the horizontal direction (lateral direction in the plane of FIG. 32) is different. Is formed. Further, the radiation plate 1b is provided with a grounding hole 41 to an equipment chassis or the like.

  FIG. 33 shows another configuration example of the wideband antenna device when the radiation plate 1b is replaced with a radiation plate having a shape different from that of the radiation plate 1a. The radiation plates 1a and 1b are disposed close to each other so as to have a slot-shaped gap 21 having a predetermined gap length, and the power feeding unit 3 is provided at a predetermined position near the slot opening end of the gap 21. In the case of the example of FIG. 33, the radiation plate 1b is formed to have a size different from the total length in the slot longitudinal direction of the radiation plate 1a and the maximum spread width in the horizontal direction (substantially lateral direction in the paper of FIG. 33). Further, the radiation plate 1b is provided with a grounding hole 41 to an equipment chassis or the like.

  FIG. 34 shows another configuration example of the wideband antenna device when the radiation plate 1b is replaced with a radiation plate having a shape different from that of the radiation plate 1a. The radiation plates 1a and 1b are disposed close to each other so as to have a slot-shaped gap 21 having a predetermined gap length, and the power feeding unit 3 is provided at a predetermined position near the slot opening end of the gap 21. In the example of FIG. 34, the radiation plate 1b is formed to have the same size as the entire length in the slot longitudinal direction of the radiation plate 1a, but the maximum spread width in the horizontal direction (lateral direction in the plane of FIG. 34) is different. Is formed.

  As described above, the broadband antenna apparatus shown in FIGS. 32 to 34 is basically configured as a single-pole type (monopole type, λ / 4 type) semi-grounding system, and has an external conductor of a feeder line (not shown). Is an unbalanced power supply ground type that connects to the radiation plate 1b. In this wideband antenna device, the radiation plate 1b constituting the grounding pattern is disposed close to the radiation plate 1a so as to have a slot-shaped gap 21 having a predetermined gap length, thereby achieving excellent matching. Better VSWR characteristics can be obtained. That is, the radiating plate 1a is mainly composed of a small chip antenna or a pattern antenna, and the radiating plate 1a is provided with a radiating plate 1b which is a ground-side pattern so as to have a slot-shaped gap 21. Is to be realized.

  In the above description, the plate-shaped broadband antenna device has been described as an example. However, the present invention is not limited to this, and for example, it may be formed in a cylindrical shape. A configuration example in that case is shown in FIG. FIG. 35A shows a bipolar (dipole type, λ / 2 type) antenna device that is formed in a cylindrical shape so that the center line Q is the central axis of the cylinder. FIG. 35B shows a single pole type (monopole type, λ / 4 type) antenna device that is formed in a cylindrical shape so that the center line Q is the central axis of the cylinder.

  As described above, by forming the radiation plates 1a and 1b in a cylindrical shape, it is possible to realize an antenna device with excellent space efficiency.

It is a figure which shows the antenna device provided with the conventional semicircle-shaped radiation plate. It is a figure which shows the antenna device provided with the radiation plate of the conventional isosceles triangle shape. It is a figure which shows an antenna apparatus when the radius of a radiation plate shall be 0.25 (lambda). It is a figure which shows the VSWR characteristic of the antenna apparatus of FIG. It is a figure which shows the single pole type | mold antenna apparatus which operate | moves equivalent to the antenna apparatus shown in FIG. It is a figure which shows the example of a fundamental structure of the wideband antenna apparatus which concerns on this invention. It is a figure which shows the VSWR characteristic in the case of the electric power feeding part 3-1 of FIG. It is a figure which shows the VSWR characteristic in the case of the electric power feeding parts 3-2 and 3-3 of FIG. It is a figure which shows typically the example which forms the similar structure of a triangular plate-shaped area on the basis of the electric power feeding part 3-2. It is a figure which shows typically the example which forms the similar structure of a triangular plate-shaped area on the basis of the electric power feeding part 3-3. It is a figure which shows the structural example of one Embodiment of a wideband antenna apparatus. It is the elements on larger scale near the gap | interval of FIG. It is a figure which shows the antenna apparatus in the case of each aspect ratio. It is a figure which shows the VSWR characteristic of the antenna apparatus in the case of aspect ratio m = 1. It is a figure which shows the VSWR characteristic of the antenna apparatus in the case of aspect ratio m = 0.82. It is a figure which shows the VSWR characteristic of the antenna apparatus in the case of aspect ratio m = 0.67. It is a figure which shows the VSWR characteristic of the antenna apparatus in the case of aspect ratio m = 0.49. It is a figure which shows the VSWR characteristic of the antenna apparatus in the case of aspect ratio m = 0.33. It is a figure which shows the wideband antenna device provided with the 1/4 circular shaped radiation plate. It is a figure which shows the VSWR characteristic of the antenna apparatus shown in FIG. It is a figure which shows the wideband antenna device provided with the deformation | transformation 1/4 circular shaped radiation plate. It is a figure which shows the VSWR characteristic of the antenna apparatus shown in FIG. It is a figure which shows the wideband antenna apparatus provided with the semi-elliptical radiation board. It is a figure which shows the VSWR characteristic of the antenna apparatus shown in FIG. It is a figure which shows the broadband antenna apparatus provided with the radiation plate of an isosceles triangle shape. It is a figure which shows the VSWR characteristic of the antenna apparatus shown in FIG. It is a figure which shows the broadband antenna apparatus provided with the square-shaped radiation plate. It is a figure which shows the VSWR characteristic of the antenna apparatus shown in FIG. It is a figure which shows the structural example at the time of designing the antenna apparatus shown in FIG. 19 by the magnitude | size of 4.6 times. It is a figure which shows the VSWR characteristic of the antenna apparatus shown in FIG. It is a figure which shows a single pole type wideband antenna apparatus. It is a figure which shows the wideband antenna device provided with the irregularly shaped radiation plate. It is a figure which shows the broadband antenna apparatus of the other example provided with the irregularly shaped radiation plate. It is a figure which shows the broadband antenna apparatus of the other example provided with the irregularly shaped radiation plate. It is a figure which shows the structural example at the time of forming a wideband antenna apparatus in cylindrical shape.

Explanation of symbols

  1a, 1b Radiation plate, 3 Feeder, 11 Planar conductor ground plate, 21 Gap

Claims (2)

The first radiation plate and the second radiation plate are arranged close to each other so as to face each other,
A gap is formed between the first radiating plate and the second radiating plate which are disposed in proximity to each other,
A power feeding portion is provided at a position near the opening end of the gap, and in a range represented by s / 3 ± 10%, where s is the length in the longitudinal direction of the gap,
The width of the gap at the opening end close to the power feeding portion is larger than the width of the gap at the opening end away from the power feeding portion, and the width of the gap at the position where the power feeding portion is provided is 0. An antenna device in which the shape of the first radiation plate and the second radiation plate is formed in a tapered shape from the feeding portion toward both opening ends so as to have a width of 1 to 0.5 mm . When the length in the longitudinal direction of the gap formed between the first radiation plate and the second radiation plate is s and the maximum spread width of the first radiation plate is k, the aspect ratio m is s The antenna device according to claim 1, wherein the antenna device is expressed by / 2k, and the value is in a range of 0.3 <m <0.7 .

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