JP7485452B2 - Wideband Omnidirectional Antenna - Google Patents

Description

This disclosure relates to a wideband omnidirectional linearly polarized antenna with good matching characteristics over a wide frequency band, and in particular to a wideband omnidirectional antenna that can be realized in a small size with a thin and low profile.

Disk monopole antennas are known as omnidirectional, vertically linearly polarized, broadband antennas with good matching characteristics over a wide frequency band. Good matching characteristics over a wide frequency band (wideband matching characteristics) means that there is little variation in input impedance over a wide frequency band. For example, this means that the return loss characteristics (sometimes called S11 characteristics or reflection coefficient characteristics) are kept low over a wide band.

A disk monopole antenna has a structure (configuration) in which a thin circular conductor is placed vertically as a radiating element on a flat conductive ground plate, and power is supplied via a coaxial cable. The disk monopole antenna described in Non-Patent Document 1 has good matching characteristics over a wide frequency band with a frequency ratio of 1:8, and is omnidirectional in the azimuth direction.

However, the diameter of the circular disk that is the radiating element of the antenna described in Non-Patent Document 1 must be 1/4 wavelength (0.25 wavelength) of the design frequency. Furthermore, experimental results of the antenna described in Non-Patent Document 1 show that the matching characteristics are good at or above 2.5 GHz (gigahertz) as the lower frequency limit of the band. Since the wavelength of 2.5 GHz is 120 mm (millimeters), 25 mm/120 mm ≒ 0.21 wavelength. This shows that this disk monopole antenna requires a disk diameter of at least 0.21 wavelength. In other words, with the conventional technology described in Non-Patent Document 1, it is difficult to realize an antenna that is lower in profile than 0.21 wavelength while still remaining thin.

Patent document 1 describes an antenna comprising: "a first and a second antenna element configured to transmit and receive signals in a first frequency band and a second frequency band, the first antenna element and the second antenna element having a higher frequency in the second frequency band than the first frequency band; a first delay line pair connected to the first antenna element and a second delay line pair connected to the second antenna element, the first delay line in the first delay line pair and the second delay line pair being configured to shift the phase of an electrical signal connected to the first antenna element and the second antenna element so that the first impedance of the antenna is substantially equal in the first frequency band and the second frequency band, and the second delay line in the first delay line pair and the second delay line pair being configured to convert the first impedance to a second impedance." Patent document 1 does not disclose a thin and low-profile wideband omnidirectional antenna, for example, a profile lower than 0.21 wavelengths.

Title of the paper: "A DISK MONOPOLE ANTENNA WITH 1:8 IMPEDANCE BANDWIR|DTH AND OMNIDIRECTIONAL RADIATION PATTERN" Name of the conference: ISAP'92 (International Symposium on Antenna and Propagation 1992) Publication: PROCEEDINGS OF ISAP'92, pp. 1145-1148 JP 2009-533957 A

As described above, the techniques described in Non-Patent Document 1 and Patent Document 1 make it difficult to realize a thin, low-profile, and small-sized broadband omnidirectional antenna, particularly a broadband omnidirectional antenna with a profile lower than 0.21 wavelengths, and such an antenna is desired.

The objective of this disclosure is to provide a wideband omnidirectional antenna that solves the above-mentioned problems.

The wideband omnidirectional antenna according to the present disclosure comprises:
a ground plate having a ground surface including a first direction and a second direction intersecting the first direction;
a short circuit portion extending from a portion of the ground plane in a third direction intersecting the first direction and the second direction;
a first conductor plate connected to the short circuit portion, the first conductor plate having a length in the first direction longer than a length in the first direction of the short circuit portion, and extending in the third direction;
a first bent portion connected to an end portion of the first conductor plate in the third direction and extending in the second direction;
a second bent portion connected to a joint portion of a first surface of the first conductor plate that is a surface in the second direction and extending in the second direction;
a second conductor plate connected to an end of the second bent portion in the second direction and extending in a direction opposite to the third direction;
a power supply portion connected to an end portion of the second conductor plate opposite to the third direction;
Equipped with.

The wideband omnidirectional antenna according to the present disclosure comprises:
a ground plate having a ground surface including a first direction and a second direction intersecting the first direction;
a short circuit portion extending from a portion of the ground plane in a third direction intersecting the first direction and the second direction;
a first conductor plate connected to the short circuit portion, the first conductor plate having a length in the first direction longer than a length in the first direction of the short circuit portion, and extending in the third direction;
a second bent portion connected to a joint portion of a first surface of the first conductor plate that is a surface in the second direction and extending in the second direction;
a second conductor plate connected to an end of the second bent portion in the second direction and extending in a direction opposite to the third direction;
a power supply portion connected to an end portion of the second conductor plate opposite to the third direction;
Equipped with.

This disclosure makes it possible to provide a wideband omnidirectional antenna that is thin, low-profile, and compact.

1 is a perspective view illustrating a wideband omnidirectional antenna according to a first embodiment; 1 is a perspective view illustrating the operation of the wideband omnidirectional antenna according to the first embodiment; 1 is a perspective view illustrating the operation of the wideband omnidirectional antenna according to the first embodiment; 1 is a perspective view illustrating the operation of the wideband omnidirectional antenna according to the first embodiment; 1 is a perspective view illustrating a calculation model of a wideband omnidirectional antenna according to a first embodiment; 3B is a graph illustrating calculation results for the wideband omnidirectional antenna shown in FIG. 3A. 3B is a graph illustrating calculation results for the wideband omnidirectional antenna shown in FIG. 3A. 3B is a graph illustrating calculation results for the wideband omnidirectional antenna shown in FIG. 3A. 11 is a perspective view illustrating a wideband omnidirectional antenna according to a second embodiment. FIG. 11 is a perspective view illustrating a wideband omnidirectional antenna according to a third embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to a fourth embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to a fifth embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to a fifth embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to a sixth embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to a seventh embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to a seventh embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to a seventh embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to a seventh embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to an eighth embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to an eighth embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to an eighth embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to an eighth embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to a ninth embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to a ninth embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to a ninth embodiment. FIG. 13 is a perspective view illustrating a wideband omnidirectional antenna according to a ninth embodiment. FIG.

Below, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding elements are given the same reference numerals, and duplicate explanations will be omitted as necessary to clarify the explanation.

[First embodiment]
<Configuration>
FIG. 1 is a perspective view illustrating a wideband omnidirectional antenna according to a first embodiment.
In FIG. 1, the upward direction is the Z direction, and directions perpendicular to the Z direction are the X direction and the Y direction.
The X direction may be referred to as a first direction, the Y direction may be referred to as a second direction, and the Z direction may be referred to as a third direction.

As shown in FIG. 1, the wideband omnidirectional antenna 10 according to the first embodiment includes a ground plate 101, a conductor plate A, a conductor plate B, and a power supply section 107.

The conductor plate A has a first conductor plate 103, a first bent portion 104 bent into an L shape at the end 103t of the first conductor plate 103 in the Z direction, and a narrow short circuit portion 102 provided at the end (lower end) of the first conductor plate 103 in the opposite direction in the Z direction.

The conductor plate B has a second conductor plate 106 and a second bent portion 105 bent into an L-shape at the Z-direction end portion 105t of the second conductor plate 106.

The ground plate 101 has a ground surface 101s that includes an X direction and a Y direction that intersects with the X direction. The X direction is sometimes referred to as the first direction, the Y direction is sometimes referred to as the second direction, and the Z direction is sometimes referred to as the third direction.

The short circuit portion 102 extends from a portion 101p of the ground surface 101s in the Z direction intersecting the X and Y directions. The short circuit portion 102 is electrically and physically connected to the ground plate 101. The first conductor plate 103 is connected to the short circuit portion 102, has a length in the X direction longer than the length of the short circuit portion 102 in the X direction, and extends in the Z direction. The first bent portion 104 is connected to the Z direction end portion 103t of the first conductor plate 103, and extends in the Y direction.

The second bent portion 105 is connected to the joint portion 103p of the first surface 103s, which is the Y-direction surface of the first conductor plate 103, and extends in the Y-direction. The second conductor plate 106 is connected to the Y-direction end portion 105t of the second bent portion 105, and extends in the opposite direction to the Z-direction.

The power supply unit 107 is connected to the end 106t of the second conductor plate 106 in the opposite direction in the Z direction. The power supply unit 107 supplies power between an arbitrary position of the end 106t of the second conductor plate 106 in the opposite direction in the Z direction and the ground plate 101.

The height at which the second bent portion 105 of conductor plate B is provided is lower than the height at which the first bent portion 104 of conductor plate A is provided. In other words, the Z-direction length h2 of the second conductor plate 106 is shorter than the Z-direction length h1 of the first conductor plate 103. The first bent portion 104 of conductor plate A and the second bent portion 105 of conductor plate B are arranged to face each other. The end of the second bent portion 105 of conductor plate B is electrically and physically connected to the middle portion (joint portion 103p) of conductor plate A.

The shapes of conductor plate A when viewed from the opposite direction to the Y direction and conductor plate B when viewed from the Y direction are rectangular, but are not limited to this. The shapes of conductor plate A and conductor plate B may be polygonal, any curve, and/or a combination of these shapes. In addition, the angle between first bent portion 104 and first conductor plate 103, and the angle between second bent portion 105 and second conductor plate 106 do not need to be a right angle (90 degrees) and may be any angle.

<Operation>
The operating principle of the wideband omnidirectional antenna 10 will now be described.
The reason why the wideband omnidirectional antenna 10 has a low profile and a wide frequency band will be explained below with respect to low, mid, and high frequencies.

FIG. 2A is a perspective view illustrating the operation of the wideband omnidirectional antenna according to the first embodiment.
FIG. 2A is a perspective view illustrating the low frequency, or lower frequency, operation of a wideband omnidirectional antenna.

As shown in FIG. 2A, the low-frequency current fed from the power feeder 107 is distributed as shown by current distribution Id1. The path length of current distribution Id1 is approximately 1/4 wavelength of the low-frequency. Therefore, the operation of the wideband omnidirectional antenna 10 is similar to that of a 1/4 wavelength monopole antenna.

FIG. 2B is a perspective view illustrating the operation of the wideband omnidirectional antenna according to the first embodiment.
FIG. 2B is a perspective view illustrating mid-frequency operation of a wideband omnidirectional antenna.

As shown in FIG. 2B, the mid-frequency current fed from the power feeder 107 is distributed as shown by current distribution Id2. The path length of current distribution Id2 is approximately 1/4 wavelength of the mid-frequency. Therefore, the operation of the wideband omnidirectional antenna 10 is similar to that of a 1/4 wavelength monopole antenna.

FIG. 2C is a perspective view illustrating the operation of the wideband omnidirectional antenna according to the first embodiment.
FIG. 2C is a perspective view illustrating the high frequency, or upper frequency limit, operation of a wideband omnidirectional antenna.

As shown in FIG. 2C, the high-frequency current fed from the power feeder 107 is distributed as shown by current distribution Id3. The path length of current distribution Id3 is approximately 1/4 wavelength of the high-frequency. Therefore, the operation of the wideband omnidirectional antenna 10 is similar to that of a 1/4 wavelength monopole antenna.

＜Effects＞
The effects of the wideband omnidirectional antenna 10 will be explained using the results of calculations performed by simulation.
FIG. 3A is a perspective view illustrating a calculation model of the wideband omnidirectional antenna according to the first embodiment.
FIG. 3A shows the shape of an antenna model used when performing calculations to confirm the effect of the wideband omnidirectional antenna 10.

As shown in FIG. 3A, the height of the wideband omnidirectional antenna 10 is 210 mm (millimeters), and the radius of the ground plate 101 is 1332 mm. Other dimensions of the wideband omnidirectional antenna 10 are as shown in FIG. 3A.

FIG. 3B is a graph illustrating calculation results for the wideband omnidirectional antenna shown in FIG. 3A.
FIG. 3B shows the calculation results of the VSWR (Voltage Standing Wave Ratio) characteristic, which is one of the matching characteristics.
The horizontal axis of FIG. 3B represents frequency, and the vertical axis represents VSWR.

As shown in Figure 3B, the VSWR is 3.0 or less when the frequency is between 213 MHz and 843 MHz (megahertz). In this case, the center frequency is 528 MHz, so the relative bandwidth is 119% (percent), which means it has very wideband characteristics.

The lower limit frequency is 213 MHz, and the corresponding wavelength is 1408 mm. The height of the antenna is 210 mm, so when converted to wavelength, it is 210 mm/1408 mm=0.15 wavelength. In this way, the wideband omnidirectional antenna 10 according to embodiment 1 has a height of 0.15 wavelength and can be realized with a very low profile.

The length (thickness) of the wideband omnidirectional antenna 10 in the Y direction, i.e., the length of the first bent portion 104 and the second bent portion 105 in the Y direction, is 10 mm. This length is approximately 7/1000ths of a wavelength of 1408 mm for 213 MHz, which is the lower limit frequency (lowest usable frequency) shown in FIG. 3B. Therefore, it can be said that the thickness of the wideband omnidirectional antenna 10 is sufficiently thin compared to the wavelength.

FIG. 3C is a graph illustrating calculation results for the wideband omnidirectional antenna shown in FIG. 3A.
FIG. 3C shows the calculation results of the directivity characteristics in the elevation plane.
3C, the horizontal axis represents the angle θ, and the vertical axis represents the antenna gain, which is shown in absolute terms.
The relationship between the wideband omnidirectional antenna and the coordinate system is as shown in FIG. 3A.

Figure 3C shows the directivity of the wideband omnidirectional antenna 10 in the YZ plane, i.e., the plane with an azimuth angle φ = 90 degrees. The polarization is an Eθ component, i.e., a vertical polarization component when viewed from the horizontal. The angle θ is 0 degrees at the zenith and 90 degrees at the horizontal. The frequencies are displayed as low frequency 213 MHz, mid frequency 350 MHz, and high frequency 528 MHz.

As shown in Figure 3C, at an angle θ = 60 degrees, i.e., an elevation angle of 30 degrees from the horizontal, the antenna gain takes on a bidirectional mountain shape, confirming a typical omnidirectional shape in the azimuth direction.

FIG. 3D is a graph illustrating calculation results for the wideband omnidirectional antenna shown in FIG. 3A.
FIG. 3D shows the calculation results of the directivity in the azimuth plane of a wideband omnidirectional antenna.
3D, the horizontal axis represents the azimuth angle φ, and the vertical axis represents the antenna gain, which is expressed as an absolute gain.
The relationship between the wideband omnidirectional antenna and the coordinate system is as shown in FIG. 3A.

Figure 3D shows the directivity of the wideband omnidirectional antenna 10 in the XY plane, i.e., the plane at angle θ = 90 degrees. The polarization is an Eθ component, i.e., a vertically polarized component when viewed from the horizontal. The frequencies are shown as a low frequency of 213 MHz, a mid frequency of 350 MHz, and a high frequency of 528 MHz.

As shown in Figure 3D, a uniform antenna gain is obtained at azimuth angles φ = 0 to 360 degrees. The antenna gain fluctuation range is approximately 3 dB (decibels) or less at each frequency.

According to the calculation results described above (see Figures 3A to 3D), the wideband omnidirectional antenna 10 has a thickness of approximately 7/1000 wavelengths for the lower limit frequency of 213 MHz, which is sufficiently thin compared to the wavelength. In addition, the wideband omnidirectional antenna 10 has a height of 0.15 wavelengths for the lower limit frequency of 213 MHz, which is a very low profile. In addition, the wideband omnidirectional antenna 10 has a fractional bandwidth of 119%, which is very wideband.

From this, it can be seen that the wideband omnidirectional antenna 10 has a thin, low-profile shape and is an antenna that radiates vertically polarized waves over a wide band. This advantage is particularly effective in cases where a thin, low-profile, small antenna is required. Thus, according to embodiment 1, it is possible to provide a wideband omnidirectional antenna that can be realized in a thin, low-profile, and small size.

The features of the wideband omnidirectional antenna 10 are also described below.
The matching characteristic is wideband (see FIG. 3B), that is, the input impedance characteristic is wideband.
Vertical linear polarization is the main polarization (see Figure 3C).
The directivity in the azimuth direction is omnidirectional, and uniform gain is obtained in the azimuth direction (see FIG. 3D).
- The antenna is thin (see Figure 3A).
The antenna height is low, making it possible to realize a low-profile antenna (see FIG. 3A).

[Embodiment 2]
<Configuration>
FIG. 4 is a perspective view illustrating a wideband omnidirectional antenna according to the second embodiment.
In FIG. 4, the upward direction is the Z direction, and the directions perpendicular to the Z direction are the X direction and the Y direction.
The X direction may be referred to as a first direction, the Y direction may be referred to as a second direction, and the Z direction may be referred to as a third direction.

As shown in FIG. 4, the wideband omnidirectional antenna 20 according to the second embodiment differs from the wideband omnidirectional antenna 10 according to the first embodiment in that it does not have a first bent portion 104. The wideband omnidirectional antenna 20 according to the second embodiment includes a conductor plate A, a conductor plate B, a ground plate 101, and a power supply portion 107.

The conductor plate A has a first conductor plate 103 and a narrow short circuit portion 102 at the end (lower end) of the first conductor plate 103 in the opposite direction in the Z direction.

The conductor plate B has a second conductor plate 106 and a second bent portion 105 bent into an L-shape at the Z-direction end portion 105t of the second conductor plate 106.

The ground plate 101 has a ground surface 101s that includes an X direction and a Y direction that intersects with the X direction.

The short circuit portion 102 extends from a portion 101p of the ground surface 101s in a Z direction intersecting the X and Y directions. The short circuit portion 102 is electrically and physically connected to the ground plate 101. The first conductor plate 103 is connected to the short circuit portion 102, has a length in the X direction longer than the length of the short circuit portion 102 in the X direction, and extends in the Z direction.

The second bent portion 105 is connected to the joint portion 103p of the first surface 103s, which is the Y-direction surface of the first conductor plate 103, and extends in the Y-direction. The second conductor plate 106 is connected to the Y-direction end portion 105t of the second bent portion 105, and extends in the opposite direction to the Z-direction.

The power supply unit 107 is connected to the end 106t of the second conductor plate 106 in the opposite direction in the Z direction. The power supply unit 107 supplies power between an arbitrary position of the end 106t of the second conductor plate 106 in the opposite direction in the Z direction and the ground plate 101.

[Embodiment 3]
<Configuration>
FIG. 5 is a perspective view illustrating a wideband omnidirectional antenna according to the third embodiment.
In FIG. 5, the upward direction is the Z direction, and the directions perpendicular to the Z direction are the X direction and the Y direction.
The X direction may be referred to as a first direction, the Y direction may be referred to as a second direction, and the Z direction may be referred to as a third direction.

As shown in FIG. 5, the wideband omnidirectional antenna 30 according to the third embodiment has a different shape of the ground plate 301 compared to the wideband omnidirectional antenna 10 according to the first embodiment. The shape of the ground plate 301 of the wideband omnidirectional antenna 30, as viewed from the Z direction, is not limited in two dimensions and may be any shape, such as a circle, an ellipse, a square, a rectangle, or a polygon.

[Fourth embodiment]
<Configuration>
FIG. 6 is a perspective view illustrating a wideband omnidirectional antenna according to the fourth embodiment.
In FIG. 6, the upward direction is the Z direction, and the directions perpendicular to the Z direction are the X direction and the Y direction.
The X direction may be referred to as a first direction, the Y direction may be referred to as a second direction, and the Z direction may be referred to as a third direction.

6, the wideband omnidirectional antenna 40 according to the fourth embodiment has a different shape of the ground plate 401 compared to the wideband omnidirectional antenna 10 according to the first embodiment. The shape of the ground plate 401 of the wideband omnidirectional antenna 40 includes a part of a cylindrical surface, a part of a spherical surface, or a part of an elliptical sphere. In the wideband omnidirectional antenna 40, the shape of the ground plate 401 is not three-dimensionally restricted, and the ground plate 401 may be configured with a cylinder, a column, a sphere, an elliptical sphere, a part of these, any other three-dimensional curved surface, or a shape combining these with a plane, etc.
[Embodiment 5]
<Configuration>
FIG. 7 is a perspective view illustrating a wideband omnidirectional antenna according to the fifth embodiment.
In FIG. 7, the upward direction is the Z direction, and the directions perpendicular to the Z direction are the X direction and the Y direction.
The X direction may be referred to as a first direction, the Y direction may be referred to as a second direction, and the Z direction may be referred to as a third direction.

As shown in FIG. 7, the wideband omnidirectional antenna 50 according to the fifth embodiment differs from the wideband omnidirectional antenna 10 according to the first embodiment in the position of the power supply unit 107. The power supply unit 107 is connected to the end 106t (lower end) of the second conductor plate 106 in the opposite direction in the Z direction.

The position of the power supply unit 107 (power supply location) may be any position on the end 106t of the conductor plate B. Specifically, the position of the power supply unit 107 is set to a position on the end 106t of the conductor plate B that provides the best input impedance characteristics.

FIG. 8 is a perspective view illustrating a wideband omnidirectional antenna according to the fifth embodiment.
In FIG. 8, the upward direction is the Z direction, and the directions perpendicular to the Z direction are the X direction and the Y direction.
The X direction may be referred to as a first direction, the Y direction may be referred to as a second direction, and the Z direction may be referred to as a third direction.

As shown in FIG. 8, the power supply unit 107 of the wideband omnidirectional antenna 50 is specifically composed of a coaxial cable 507 having a coaxial center conductor 507a and a coaxial outer conductor 507b. The power supply unit 107 supplies power using the coaxial cable 507.

The coaxial outer conductor 507b is electrically connected to the ground plate 101, and the coaxial central conductor 507a is electrically connected to an arbitrary position of the end 106t of the conductor plate B (second conductor plate 106). When using a coaxial connector, the outer conductor of the coaxial connector is connected to the bottom surface of the ground plate 101, and the central conductor of the coaxial connector is connected to the end 106t of the conductor plate B. This allows power to be supplied to the wideband omnidirectional antenna 50.

Sixth Embodiment
<Configuration>
FIG. 9 is a perspective view illustrating a wideband omnidirectional antenna according to the sixth embodiment.
In FIG. 9, the upward direction is the Z direction, and the directions perpendicular to the Z direction are the X direction and the Y direction.
The X direction may be referred to as a first direction, the Y direction may be referred to as a second direction, and the Z direction may be referred to as a third direction.

As shown in FIG. 9, the wideband omnidirectional antenna 60 according to the sixth embodiment differs from the wideband omnidirectional antenna 10 according to the first embodiment in the position of the short circuit portion 102. The short circuit portion 102 is connected to the end portion in the reverse direction in the Z direction of the first conductor plate 103. The position of the short circuit portion 102 is any position on the end portion in the reverse direction in the Z direction of the conductor plate A. Specifically, the position of the short circuit portion 102 is set at any position on the end portion (lower end portion) in the reverse direction in the Z direction of the conductor plate A, at which the input impedance characteristics are best.

[Embodiment 7]
<Configuration>
10A to 10D are perspective views illustrating a wideband omnidirectional antenna according to the seventh embodiment.
10A to 10D, the upward direction is defined as the Z direction, and the directions perpendicular to the Z direction are defined as the X direction and the Y direction.
The X direction may be referred to as a first direction, the Y direction may be referred to as a second direction, and the Z direction may be referred to as a third direction.

As shown in FIG. 10A, the wideband omnidirectional antenna 70 according to the seventh embodiment differs from the wideband omnidirectional antenna 10 according to the first embodiment in that the end (lower end) of the conductor plate B (second conductor plate 106) in the opposite direction to the Z direction is slanted when viewed from the Y direction. By slanting the end, the distance to the ground plate 101 changes, making it easier to adjust the input impedance.

As shown in FIG. 10B, the wideband omnidirectional antenna 70 according to the seventh embodiment differs from the wideband omnidirectional antenna 10 according to the first embodiment in that the end (lower end) of the conductor plate B (second conductor plate 106) in the opposite direction to the Z direction when viewed from the Y direction has an acute angle. By making the angle of the end an acute angle, the distance to the ground plate 101 changes, making it easier to adjust the input impedance.

As shown in FIG. 10C, the wideband omnidirectional antenna 70 according to embodiment 7 differs from the wideband omnidirectional antenna 10 according to embodiment 1 in that the end (lower end) of conductor plate B (second conductor plate 106) in the opposite direction in the Z direction is slanted, and the end (lower end) of conductor plate A (first conductor plate 103) in the opposite direction in the Z direction is slanted. By slanting the lower ends of conductor plate B and conductor plate A, the distance between them and the ground plate 101 changes, making it easier to adjust the input impedance.

As shown in FIG. 10D, the wideband omnidirectional antenna 70 according to embodiment 7 differs from the wideband omnidirectional antenna 10 according to embodiment 1 in that the end (lower end) of conductor plate B (second conductor plate 106) in the opposite direction in the Z direction is slanted, and the end (lower end) of conductor plate A (first conductor plate 103) in the opposite direction in the Z direction is at an acute angle. This changes the distance to the ground plate 101, making it easier to adjust the input impedance.

In summary, the shape of the first conductor plate 103 of the wideband omnidirectional antenna 70 is a polygon or a shape formed by an arbitrary curve when viewed from the opposite direction to the Y direction. The shape of the second conductor plate 106 is a polygon or a shape formed by an arbitrary curve when viewed from the Y direction.

In addition, the combinations of the bottom ends of conductor plates A and B of the wideband omnidirectional antenna 70 are not limited to those shown in Figures 10A to 10D, and individual combinations of each part are possible. Furthermore, the shape of the bottom end is not limited to a straight line, and any curve or a combination of a curve and a straight line is also possible.

[Embodiment 8]
<Configuration>
11A to 11D are perspective views illustrating a wideband omnidirectional antenna according to the eighth embodiment.
11A to 11D, the upward direction is defined as the Z direction, and the directions perpendicular to the Z direction are defined as the X direction and the Y direction.
The X direction may be referred to as a first direction, the Y direction may be referred to as a second direction, and the Z direction may be referred to as a third direction.

As shown in FIG. 11A, the wideband omnidirectional antenna 80 according to embodiment 8 differs from the wideband omnidirectional antenna 10 according to embodiment 1 in that the shape of the first bent portion 104 is trapezoidal when viewed from the Z direction. By making the shape of the first bent portion 104 trapezoidal, diversity in the current distribution path is obtained, making it easier to adjust the wideband characteristic and matching state. The reason for this is that the overlapping area between the opposing conductor plates A and B changes, allowing adjustment of the electromagnetic coupling.

Although the above description is of the case where the shape of the first bent portion 104 is trapezoidal when viewed from the Z direction, the same effect can be obtained by making the bottom end or side end of conductor plate A or conductor plate B a dogleg polygon or curved. The reason for this is that the distance between the bottom end or side end of conductor plate A and ground plate 101, or the distance between the bottom end or side end of conductor plate B and ground plate 101, changes, making it possible to adjust the electromagnetic coupling.

As shown in FIG. 11B, the wideband omnidirectional antenna 80 according to the eighth embodiment differs from the wideband omnidirectional antenna 10 according to the first embodiment in that the first bent portion 104 at the upper end of the conductor plate A is bent obliquely when viewed from the opposite direction to the Y direction. By bending the first bent portion 104 obliquely, the diversity of the current distribution path is obtained, and it is easy to adjust the wideband characteristic and matching state.

As shown in FIG. 11C, the wideband omnidirectional antenna 80 according to the eighth embodiment differs from the wideband omnidirectional antenna 10 according to the first embodiment in that the shape of the second bend 105 at the upper end of the conductor plate B is a trapezoid when viewed from the Z direction that is different from the trapezoid shape of the first bend 104. By making the second bend 105 a trapezoid when viewed from the Z direction, the distance in the Y direction between the conductor plate B and the conductor plate A changes, and the degree of electromagnetic coupling changes, making it easier to adjust the wideband characteristic and matching state.

As shown in FIG. 11D, the wideband omnidirectional antenna 80 according to embodiment 8 differs from the wideband omnidirectional antenna 10 according to embodiment 1 in that the second bent portion 105 and the joint portion 103p at the upper end of the conductor plate B are joined at an angle when viewed from the Y direction. By joining the second bent portion 105 and the joint portion 103p at an angle, a diversity of paths for the current distribution is obtained, and it is easy to adjust the wideband characteristic and matching state.

Note that the shapes of conductor plate A, conductor plate B, first bent portion 104, second bent portion 105, and joint portion 103p can be combined in a variety of ways other than those shown in Figures 11A to 11D. Also, while the shapes shown in Figures 11A to 11D have been described as being straight lines, these shapes are not limited to straight lines and can also be any curved line or a combination of a curved line and a straight line.

Ninth Embodiment
<Configuration>
12A to 12D are perspective views illustrating a wideband omnidirectional antenna according to the ninth embodiment.
12A to 12D, the upward direction is defined as the Z direction, and directions perpendicular to the Z direction are defined as the X direction and the Y direction.
The X direction may be referred to as a first direction, the Y direction may be referred to as a second direction, and the Z direction may be referred to as a third direction.

As shown in FIG. 12A, the wideband omnidirectional antenna 90 according to the ninth embodiment differs from the wideband omnidirectional antenna 10 according to the first embodiment in that a hole 108 is arranged at an arbitrary position on the conductor plate B. That is, the second conductor plate 106 has a hole 108 of an arbitrary shape. By drilling a hole at an arbitrary position on the conductor plate B, the path of the current distribution is restricted, and the degree of electromagnetic coupling between the conductor plate A and the conductor plate B is changed, making it easier to adjust the wideband characteristic and the matching state.

As shown in FIG. 12B, the wideband omnidirectional antenna 90 according to the ninth embodiment differs from the wideband omnidirectional antenna 10 according to the first embodiment in that a hole 108 is arranged at an arbitrary position on the conductor plate A. That is, the first conductor plate 103 has a hole 108 of an arbitrary shape. By drilling a hole at an arbitrary position on the conductor plate A, the path of the current distribution is restricted, and the degree of electromagnetic coupling between the conductor plate A and the conductor plate B is changed, making it easier to adjust the wideband characteristic and the matching state.

As shown in FIG. 12C, the wideband omnidirectional antenna 90 according to the ninth embodiment differs from the wideband omnidirectional antenna 10 according to the first embodiment in that a hole 108a is arranged at an arbitrary position on the conductor plate A, and a hole 108b is arranged at an arbitrary position on the conductor plate B. The positional relationship between the holes 108a and 108b is arbitrary. By drilling holes at arbitrary positions on the conductor plates A and B, the path of the current distribution is restricted, and the degree of electromagnetic coupling between the conductor plates A and B is changed, making it easy to adjust the wideband characteristic and matching state.

As shown in FIG. 12D, the wideband omnidirectional antenna 90 according to the ninth embodiment differs from the wideband omnidirectional antenna 10 according to the first embodiment in that a hole 108 is disposed in the upper part of the conductor plate A. By drilling the hole 108 in the upper part of the conductor plate A, the path of the current distribution is restricted, making it easier to adjust the wideband characteristic and the matching state.

In summary, at least one of the first conductive plate 103 and the second conductive plate 106 of the wideband omnidirectional antenna 90 has a hole 108 of any shape.

In addition to the combinations of holes 108 placed on conductor plate A and conductor plate B of the wideband omnidirectional antenna 90 shown in Figures 12A to 12D, individual combinations of each part are possible. Furthermore, the shape and position of the holes 108 are arbitrary. In particular, the shape of the holes 108 can be a circle, an ellipse, a polygon, a combination of these, etc.

The present invention is not limited to the above embodiment, and can be modified as appropriate without departing from the spirit and scope of the invention.

Reference Signs List 10, 20, 30, 40, 50, 60, 70, 80, 90...Wideband omnidirectional antenna 101, 301, 401...Ground plate 101s...Ground surface 101p...Part 102...Short circuit portion 103...First conductor plate 103s...First surface 103t...End portion 103p...Joint portion 104...First bent portion 105...Second bent portion 105t...End portion 106...Second conductor plate 106t...End portion 107...Power supply portion 507...Coaxial cable 507a...Coaxial central conductor 507b...Coaxial outer conductor 108, 108a, 108b...Hole A, B...Conductor plate Id1, Id2, Id3...Current distribution h1, h2...Length θ...Angle φ...Azimuth angle

Claims (10)

a ground plate having a ground surface including a first direction and a second direction intersecting the first direction;
a short circuit portion extending from a portion of the ground plane in a third direction intersecting the first direction and the second direction;
a first conductor plate connected to the short circuit portion, the first conductor plate having a length in the first direction longer than a length in the first direction of the short circuit portion, and extending in the third direction;
a first bent portion connected to an end portion of the first conductor plate in the third direction and extending in the second direction;
a second bent portion connected to a joint portion of a first surface of the first conductor plate that is a surface in the second direction and extending in the second direction;
a second conductor plate connected to an end of the second bent portion in the second direction and extending in a direction opposite to the third direction;
a power supply portion connected to an end portion of the second conductor plate opposite to the third direction;
A wideband omnidirectional antenna comprising: a ground plate having a ground surface including a first direction and a second direction intersecting the first direction;
a short circuit portion extending from a portion of the ground plane in a third direction intersecting the first direction and the second direction;
a first conductor plate connected to the short circuit portion, the first conductor plate having a length in the first direction longer than a length in the first direction of the short circuit portion, and extending in the third direction;
a second bent portion connected to a joint portion of a first surface of the first conductor plate that is a surface in the second direction and extending in the second direction;
a second conductor plate connected to an end of the second bent portion in the second direction and extending in a direction opposite to the third direction;
a power supply portion connected to an end portion of the second conductor plate opposite to the third direction;
A wideband omnidirectional antenna comprising: The shape of the ground plate is a circle, an ellipse, a square, a rectangle, or a polygon when viewed from the third direction.
3. A wideband omnidirectional antenna according to claim 1 or 2. The shape of the ground plate includes a part of a cylindrical surface, a part of a spherical surface, or a part of an elliptical sphere.
3. A wideband omnidirectional antenna according to claim 1 or 2. The power supply portion is connected to an end portion of the second conductor plate opposite to the third direction.
5. A wideband omnidirectional antenna according to claim 1. The short-circuit portion is connected to an end portion of the first conductor plate in a direction opposite to the third direction.
6. A wideband omnidirectional antenna according to claim 1. the first conductive plate has a shape formed of a polygon or an arbitrary curve when viewed from a direction opposite to the second direction,
The shape of the second conductive plate is a polygon or a shape formed by an arbitrary curve when viewed from the second direction.
7. A wideband omnidirectional antenna according to claim 1. the first bent portion has a trapezoidal shape when viewed from the third direction,
The shape of the second bent portion is another trapezoid when viewed from the third direction.
2. The wideband omnidirectional antenna of claim 1. At least one of the first conductive plate and the second conductive plate has a hole of any shape.
A wideband omnidirectional antenna according to any one of claims 1 to 8. the power supply unit is composed of a coaxial cable having a coaxial central conductor and a coaxial outer conductor;
the coaxial outer conductor is electrically connected to the ground plate;
the coaxial central conductor is electrically connected to the second conductive plate;
A wideband omnidirectional antenna according to any one of claims 1 to 9.

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