JPH11168320A - Omnidirectional antenna in common use for two-frequency - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an omnidirectional antenna in common use for two frequencies capable of simplifying a structure, facilitating miniaturization, lowering the manufacture cost, eliminating unrequired radiation from a power feeder line and easily realizing excellent omnidirection within a horizontal plane. SOLUTION: First and second dielectric substrates 11 and 12 are provided holding a ground conductor plate 13 there between and the first and second antenna elements 14 and 15 of different sizes are respectively formed on the surfaces of the dielectric substrates 11 and 12. A slot 16 is formed at the ground conductor plate 13 at a position between the first antenna element 14 and the second antenna element 15 and a microstrip line 17 for feeding power to the first antenna element 14 is provided. By the constitution, this omnidirectional antenna in common use for the two frequencies of excellent characteristics for simplifying the structure, facilitating miniaturization and lowering the manufacture cost is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a uniform radiation directivity in a horizontal plane used for mobile communication systems such as mobile phones and mobile communication systems such as indoor wireless LANs, and is applicable to a plurality of communication systems. A possible dual frequency omnidirectional antenna.

[0002]

2. Description of the Related Art An antenna used for a mobile communication base station or an indoor wireless communication base station has a simple and compact structure.
It is required to be thin and low cost. Regarding the radiation directivity, it is desirable that the horizontal plane be non-directional and the vertical plane be tilted downward. Furthermore, as a mobile communication such as a mobile phone, a 1.5 GHz band PD is used in Japan.
There are a plurality of systems such as C and 1.9 GHz band PHS.

Therefore, if a single antenna can simultaneously cope with a plurality of these systems, the base station antenna can be simplified, downsized, and reduced in cost. Further, the terminal antenna can be similarly simplified and reduced in size, and the price of the terminal can be reduced.

Conventionally, a mobile communication base station operates at one frequency because it supports only one system. Further, a collinear array antenna in which dipole elements for realizing beam tilt directivity are arranged in multiple stages in the vertical direction is used. However, it is difficult to use a large array antenna indoors. As an antenna meeting this requirement, the IEICE Autumn Meeting 1994 SB-1-
The “beam tilt dipole antenna for indoor base station” reported in No. 8 is known. This beam tilt dipole antenna has one excitation element 91 as shown in FIG.
And a plurality of parasitic elements 92 arranged on the circumference having a radius of d with the center as the center. The excitation element 91 is a linear element having a length ao and a radius ro, and is arranged on the z-axis. The parasitic element 92 is a linear element having a length ai and a radius ri, and is inclined at an angle γ from the z-axis. The center of the parasitic element 92 is offset by S from the center of the excitation element 91.

FIG. 10 shows the radiation directivity on the horizontal plane (a) and the radiation directivity on the vertical plane (b) when three parasitic elements 92 of the same length are arranged at 120 ° intervals in the configuration of FIG. ,
(C) is shown. As shown in the figure, good radiation directivity is obtained on both the horizontal plane and the vertical plane. In this example, γ = 30 ° and d / λ = 0.158, and the radius d of the circumference on which the parasitic element 92 is arranged is about 2.5 cm.

As described above, in the antenna shown in FIG. 9, it is necessary to arrange a plurality of parasitic elements 92 around the excitation element 91 in a spatially independent manner and with a predetermined positional relationship with the excitation element 91. , Structurally complex. Moreover,
Since the antenna element is constituted by a linear element, the unit price of the element is low, but there is a problem that the installation is very troublesome and the manufacturing cost is high.

Further, when an array is formed using this antenna element, not only the structure becomes more complicated, but also new means for feeding a coaxial feed line to many elements is required. In addition, there is a problem that manufacturing is difficult and the manufacturing cost is further increased, and unnecessary radiation from the feed line is generated to deteriorate antenna characteristics. Further, it is difficult to increase the frequency to cope with a plurality of systems as it is.

Further, Japanese Patent Publication No. 3-66578, "Nondirectional Microstrip Antenna" discloses an antenna which feeds a columnar parasitic element with a microstrip line. When this antenna is formed into an array, columnar parasitic elements are arranged at predetermined intervals in the longitudinal direction, and power is supplied to these in parallel by a microstrip feed line.

However, in this configuration, in order to supply power to the parasitic element, a plurality of microstrip lines must be provided in a cylinder forming the parasitic element, which not only complicates the structure, but also makes the cylinder complex. Has to be made larger, and the advantage of miniaturization is also lost. Further, the microstrip line has a problem in that unnecessary radiation is generated from a portion inside the parasitic element having a cylindrical shape, thereby deteriorating the characteristics of the antenna. Further, it is difficult to operate a plurality of communication systems at different frequencies using this antenna element.

[0010]

As described above, the conventional omnidirectional antenna cannot operate in a plurality of communication systems because it operates at a frequency corresponding to only one communication system.

Furthermore, when the array is used, the structure becomes complicated, it is difficult to reduce the size, and there is a problem that unnecessary radiation from the feed line is generated and the characteristics of the antenna are deteriorated.

The present invention relates to a dual-frequency antenna capable of coping with a plurality of communication systems, and has a simple structure, can be easily miniaturized, can be manufactured at a low cost, and emits unnecessary radiation from a feeder line even when an array is used. It is another object of the present invention to provide a dual-frequency omnidirectional antenna capable of easily realizing good omnidirectionality in a horizontal plane.

[0013]

In order to solve the above-mentioned problem, a dual-frequency omnidirectional antenna according to the first aspect of the present invention comprises a first and a second antenna which face each other at a predetermined interval. A dielectric substrate; a ground conductor plate provided between the first and second dielectric substrates; and a ground conductor plate formed on the surface of the first and second dielectric substrates opposite to the ground conductor plate. First and second antenna elements having different sizes, an opening formed in the ground conductor plate at a position between the first and second antenna elements, and a first antenna element. And a line for feeding power.

With such a configuration, the structure is simple, the size can be easily reduced, the manufacturing cost is low, unnecessary radiation from the power supply line is eliminated, and good omnidirectionality in a horizontal plane can be easily realized. A dual frequency omnidirectional antenna can be realized.

Further, since one service can cope with different services without using two antennas or array antennas, it is possible to reduce the size of antennas and reduce the cost of base stations and terminals.

According to a second aspect of the present invention, there is provided a dual-frequency omnidirectional antenna having first and second dielectric substrates opposed to each other with a predetermined space therebetween, and a first and a second dielectric substrates.
A ground conductor plate provided between the first and second dielectric substrates, and a first dielectric substrate formed on the first dielectric substrate on a surface opposite to the ground conductor plate, in an odd-numbered manner counted from one end thereof. A first array antenna composed of an antenna element of a size, and an antenna element of a second size different from the first size formed on each of the even-numbered antenna elements; and a ground conductor plate on a second dielectric substrate. An antenna element of a second size formed on the opposite surface in an odd-numbered form, counting from one end thereof;
And a second array antenna composed of even-numbered antenna elements of a first size, and a ground conductor plate at a position between the opposing antenna elements of the first array antenna and the second array antenna. The opening formed and one counting from one end of the first array antenna.
A line that feeds the first antenna element, a line that connects the even-numbered antenna element counted from one end of the first array antenna and the odd-numbered antenna element that is one greater than the even number, and a second array antenna. A line connecting an odd-numbered antenna element counted from one end and an even-numbered antenna element which is larger than the odd-numbered antenna element by 1;

Even in such an array configuration, the structure is simple and easy to miniaturize, the manufacturing cost is low, unnecessary radiation from the feeder line is eliminated, and good omnidirectionality in a horizontal plane can be easily achieved. An omnidirectional dual-frequency antenna that can be realized can be realized.

Further, the dual-frequency omnidirectional antenna according to the third aspect of the present invention includes first and second dielectric substrates opposed to each other with a predetermined space therebetween, and the first and second dielectric substrates. A first ground substrate provided between the dielectric substrates; and a first dielectric element comprising a plurality of antenna elements of a first size formed on a surface of the first dielectric substrate opposite to the ground conductor plate. An array antenna, and a second array antenna including a plurality of antenna elements having a second size different from the first size and formed on a surface of the second dielectric substrate opposite to the ground conductor plate. An opening formed in the ground conductor plate at a position between the opposing antenna elements of the first array antenna and the second array antenna, and a first antenna element counted from one end of the first array antenna And a first line for feeding A line connecting the even-numbered antenna element counted from one end of the array antenna to the odd-numbered antenna element that is one greater than the even number, and the odd-numbered antenna element counted from one end of the second array antenna; And a line connecting the even-numbered antenna element which is larger than the odd-numbered antenna element by one.

According to such a configuration, the two-frequency device has a simple structure, can be easily miniaturized, has a low manufacturing cost, has no unnecessary radiation from the feed line, and can easily realize good omnidirectionality in a horizontal plane. A shared omnidirectional antenna can be realized.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. FIG.
FIG. 1 is a perspective view of an entire antenna showing a first embodiment of a dual-frequency omnidirectional antenna according to the present invention.
Is an exploded perspective view thereof.

In these figures, the first of the length L and the width W
And the second dielectric substrates 11 and 12 are provided to face each other with the ground conductor plate 13 interposed therebetween, and further, the first and second dielectric substrates 11 and 12 are on the side opposite to the ground conductor plate 13, ie, The frequency f1 made of a conductive film such as a rectangular copper foil on the outer surface
The first antenna element 14 having a length La1 and a width Wa1 that resonates at a frequency f2, and a length La2 and a width Wa2 resonating at a frequency f2.
Are formed by the photolithography technique. Note that La1 <La2,
It is assumed that Wa1 <Wa2, and the second antenna element 15 is larger than the first antenna element 14.

Each of the antenna elements 14,
15 at a position below the first antenna element 14, ie, between the first antenna element 14 and the second antenna element 15, a length Ls and a width W for electromagnetically coupling the two antenna elements 14, 15 are provided.
s opening or slot 16 is provided, and a microstrip line 17 having a width Wm for feeding the first antenna element 14 is formed on the first dielectric substrate 11 side of the first antenna element 14. I have.

In FIG. 2, the first and second dielectric substrates 11 and 12 and the ground conductor plate 13 are shown in an exploded manner, however, the ground conductor plate 13 is formed of the first and second dielectric substrates. 1 is formed on one of the substrates 11 and 12, and the other dielectric substrate is superposed and adhered on the surface of the ground conductor plate 13 to produce the dual frequency omnidirectional antenna of FIG. Is done.

Next, the operation of the dual frequency omnidirectional antenna will be described. The resonance frequency f1 of the rectangular patch forming the first antenna element 14
Is higher than the resonance frequency f2 of the rectangular patch constituting When power is supplied to the first antenna element 14 shown in FIG. 1 at a high frequency f1 through the microstrip line 17, only the first antenna element 14 is excited, and the second antenna element 15 is not excited. On the other hand, when power is supplied to the first antenna element 14 at a low frequency f2, it becomes equivalent to slot coupling power supply, which is one of the electromagnetic coupling power supply methods for the second antenna element 15, and the first antenna element 14 is a microstrip line. Acts as a stub of 17
Only the antenna element 15 is excited.

Thus, the antenna shown in FIG. 1 operates at different frequencies. Next, as shown in the literature IEICE AP94-4 “CPW-fed microstrip antenna”, the first and second dielectric substrates 11 on which rectangular patch antennas are formed,
It has been clarified that the omnidirectionality can be realized in a substantially horizontal plane by reducing the width W of the twelve. Therefore, the first and second dielectric substrates 11, 1
It can be seen that omnidirectionality can be realized at two different frequencies by reducing the width of 2.

As described above, in this embodiment, the first and second dielectric substrates 11 and 12 are provided with the first and second dielectric substrates 11 and 12 at predetermined intervals. Slots 16 are provided on the surfaces of the second dielectric substrates 11 and 12 opposite to the ground conductor plate 13 for electromagnetically coupling the first and second antenna elements 14 and 15 having different sizes. With this configuration, a dual-frequency omnidirectional antenna having omnidirectionality in a horizontal plane and radiation directivity downwardly beam-tilted in a vertical plane at two frequencies is realized.

Further, since the antenna element can be formed as a patch antenna on a dielectric substrate by a photolithography technique or the like, the manufacturing is simple and the manufacturing cost is low. Furthermore, 2
Since different services can be handled by one antenna without using multiple antennas or array antennas, downsizing of antennas and reduction in cost of base stations and terminals can be realized.

Although the shape of the antenna element is a rectangular patch in FIG. 1, the shape of the antenna element is not limited to this, and various modifications are possible as shown in FIG.
Is an example of a circle, (b) is an ellipse, and (c) is an example of a triangle.

Further, the slot provided on the ground conductor plate 13 can have an arbitrary shape as shown in FIG. In FIG. 4, (a) and (b) are cross slots, (c) is a dumbbell-shaped slot, (d) is a triangle,
(E) is an ellipse and (f) is a plurality of slots, but may have other shapes. In this case, in particular, in the cross slot of (a) and the dumbbell-shaped slot of (c), the degree of coupling can be increased, and the band can be widened.

In this embodiment, the slot 16 and the microstrip line 1 are located at the center of the antenna element.
7, but the positional relationship between the two is not limited to this. Next, FIG. 5 shows, as a second embodiment of the dual-frequency omnidirectional antenna according to the present invention, a configuration in which a plurality of antennas having the basic configuration shown in FIG.

As shown in the figure, this dual-frequency omnidirectional array antenna has dielectric substrates 51 and 52 and a ground conductor plate 53 formed in a long shape, and is formed on the dielectric substrate 51 in the longitudinal direction. The antenna element 54 having the first magnitude at the resonance frequency f1 is sequentially arranged from one end, that is, from the bottom in FIG.
-1 and a second size antenna element 5 having a resonance frequency f2
By forming 4-2, the first substrate is formed on the dielectric substrate 51.
Is formed. Also, the dielectric substrate 52
On the upper side, an antenna element 55-1 of the second magnitude at the resonance frequency f2 and an antenna element 55-2 of the first magnitude at the resonance frequency f1 are formed in this order from one end, that is, from the bottom of FIG. Thus, the second array antenna 55 is formed on the dielectric substrate 52.

A microstrip line 56 for feeding the antenna element 54-1 is formed on the dielectric substrate 51.
On the dielectric substrate 52, a microstrip line 57 connecting the antenna element 55-1 having the resonance frequency f2 and the antenna element 55-2 having the resonance frequency f1 is formed. In addition, an opening or a slot 58 on the ground conductor plate 53,
59 are formed.

Next, the operation of the second embodiment will be described with reference to FIG. The antenna element 54-1 connected to the microstrip line 56 and the microstrip line 57
Slot 5 between the antenna elements 55-1 to which the
Unlike the first embodiment, this part operates as a power divider, and when a signal of the frequency f1 is input to the microstrip line 56, a part of the signal is transmitted from the antenna element 54-1. But the remaining power is transmitted to another microstrip line 57 via the slot 58, and further the antenna element 55-2
And transmitted as radio waves. The radiation directivity of each of the antenna element 54-1 and the antenna element 55-2 is shown in FIG.
(A) and (b). The antenna element 54-1 is shown in FIG.
Since the antenna element 55-2 emits a radio wave slightly stronger in the -X direction, ie, the lower side in FIG. 6, the antenna element 55-2 combines the two, as shown in FIG.
In a horizontal plane, more preferable non-directionality than the directivity of the antenna of the first embodiment can be realized.

As for the signal of the frequency f2, the same operation as described for the antenna elements 54-1 and 55-2 is performed for the antenna elements 55-1 and 54-2. It is possible to realize omnidirectionality in a horizontal plane. Therefore, omnidirectionality can be obtained at two frequencies.

Also in the case of arraying as in the second embodiment, the antenna element can be formed as a patch antenna on a dielectric substrate by photolithography technology or the like. By arraying the antenna elements on the common first and second dielectric substrates, an array can be easily realized, so that the manufacturing is simple and the manufacturing cost is low.

Further, since the microstrip line feeding the antenna elements alternately feeds the antenna elements, the microstrip lines feed the antenna elements alternately between the antenna elements of the first array antenna 54 and between the antenna elements of the second array antenna 55. Since the length of the feed line can be made shorter than in the case where power is supplied between the antennas, unnecessary radiation can be reduced, and good antenna characteristics can be obtained.

The advantages of the array antenna of the second embodiment are the same as those of the first embodiment, and more preferable omnidirectionality can be realized. In the second embodiment, when the number of antenna elements is further increased, on the dielectric substrate 51, in order from one end thereof,
By forming an odd-numbered antenna element of the first size with the resonance frequency f1 and an even-numbered antenna element with the second size of the resonance frequency f2, the dielectric substrate 5 is formed.
A first array antenna is formed on the first array antenna.

On the other hand, on the dielectric substrate 52, in order from one end thereof, an odd-numbered antenna element of the second size having the resonance frequency f2 and an even-numbered antenna element having the resonance frequency f2 are arranged in order.
By forming one first-sized antenna element, a second array antenna is formed on the dielectric substrate 52.

A microstrip for directly feeding the first antenna element counted from one end of the first array antenna and connecting the even-numbered antenna element and the odd-numbered antenna element which is larger than the even-numbered antenna element by one. Form a line. Also, the odd-numbered antenna element counting from one end of the second array antenna and one from the odd-numbered antenna element.
A microstrip line for connecting to a large even-numbered antenna element is formed. Further, at a position between the first array antenna on the dielectric substrate 51 and the opposing antenna element of the second array antenna on the opposing dielectric substrate 52, an opening or slot is formed on the ground conductor plate 53. What is necessary is just to form.

Next, a third embodiment of the dual frequency omnidirectional antenna according to the present invention will be described. This embodiment also has a configuration in which a plurality of antennas having the basic configuration shown in FIG. 1 are arranged and arrayed, but the arrangement of the antenna elements is different from that of the second embodiment.

FIG. 8 shows the configuration of the third embodiment. As shown in the figure, this dual-frequency omnidirectional array antenna includes dielectric substrates 81 and 82 and a ground conductor plate 8.
3 is formed in a long shape, and in the longitudinal direction, on the dielectric substrate 81, in order from one end thereof, that is, from the bottom in FIG. The first array antenna 84 is formed by forming the antenna element 84-2, and the resonance frequency f2 is formed on the dielectric substrate 82 from one end thereof, that is, from the bottom in FIG.
The second array antenna 85 is formed by forming the antenna elements 85-1 and 85-2 of the second size.

Then, a microstrip line 86 for feeding the antenna element 84-1 is formed on the dielectric substrate 81.
On the dielectric substrate 82, a microstrip line 87 connecting the antenna element 85-1 and the antenna element 85-2 having the resonance frequency f2 is formed. In addition, openings, that is, slots 88 and 89 are formed on the ground conductor plate 83.

When a signal of the frequency f1 is input to the microstrip line 86, a part of the signal is radiated as radio waves from the antenna element 84-1, but the remaining power is transmitted to another microstrip line 87 via the slot 88.
Further, the light is transmitted to the antenna element 84-2 via the slot 89 and emitted as a radio wave. When the signal of the frequency f2 is also input to the microstrip line 86, the signal is radiated from the antenna elements 85-1 and 85-2 as radio waves.

The signal of the frequency f1 is located on the side where the antenna element 84-1 and the antenna element 84-2 are located, and the signal of the frequency f2 is located on the side of the antenna element 85-
1 and the antenna element 85-2 emit a slightly strong radio wave. However, in practice, it can be said that omnidirectionality is realized in a substantially horizontal plane, and omnidirectionality is obtained at two frequencies. Will be done.

In the third embodiment, when the number of antenna elements is further increased, the dielectric substrate 81
The first array antenna is formed by forming a plurality of antenna elements of the first size having the resonance frequency f1 thereon, and the plurality of antenna elements having the second size of the resonance frequency f2 is formed on the dielectric substrate 82. A second array antenna is formed by forming an antenna element, and the first antenna element counted from one end of the first array antenna on the dielectric substrate 81 is directly fed to the first array antenna. And a microstrip line connecting the odd-numbered antenna element that is one greater than the even-numbered antenna element. In addition, a microstrip line connecting the odd-numbered antenna element counted from one end of the second array antenna on the dielectric substrate 82 and the even-numbered antenna element which is larger than the odd-numbered antenna element by one is formed. Further, an opening or a slot is formed on the ground conductor plate 83 at a position between the first array antenna on the dielectric substrate 81 and the opposing antenna element of the second array antenna on the opposing dielectric substrate 82. What is necessary is just to form.

[0046]

As described above, according to the present invention,
It is possible to realize a dual-frequency omnidirectional antenna that has a simple structure, is easily miniaturized, has low manufacturing costs, has no unnecessary radiation from a feed line, and can easily achieve good omnidirectionality in a horizontal plane. it can.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a dual-frequency omnidirectional antenna according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a configuration of a dual-frequency omnidirectional antenna according to the first embodiment.

FIG. 3 is a diagram showing a modification of the antenna element according to the embodiment of the present invention.

FIG. 4 is a view showing a modification of the slot according to the embodiment of the present invention.

FIG. 5 is a perspective view showing a configuration of a dual-frequency omnidirectional antenna according to a second embodiment of the present invention.

FIG. 6 is a side view for explaining the operation of the dual frequency omnidirectional antenna according to the second embodiment;

FIG. 7 is a diagram showing the radiation directivity of the dual-frequency omnidirectional antenna according to the second embodiment;

FIG. 8 is a perspective view showing a configuration of a dual-frequency omnidirectional antenna according to a third embodiment of the present invention.

FIG. 9 is a diagram showing an example of a conventional omnidirectional antenna.

FIG. 10 is a view showing the radiation directivity of the conventional example shown in FIG. 9;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... 1st dielectric substrate 12 ... 2nd dielectric substrate 13 ... ground conductor plate 14 ... 1st antenna element 15 ... 2nd antenna element 16 ... slot 17 ... microstrip line 51, 52 ... dielectric substrate 53 ground conductor plate 54 first array antenna 55 second array antenna 54-1, 54-2, 55-1, 55-2 antenna elements 56, 57 microstrip lines 58, 59 slot 81 , 82: Dielectric substrate 83: Ground conductor plate 84: First array antenna 85: Second array antenna 84-1, 84-2, 85-1, 85-2: Antenna elements 86, 87: Microstrip line 88, 89 ... slots

Claims (3)

[Claims] A first dielectric substrate facing the first dielectric substrate at a predetermined distance; a ground conductor plate provided between the first and second dielectric substrates; A first antenna element and a second antenna element having different sizes formed on a surface of the second dielectric substrate opposite to the ground conductor plate; and a first antenna element and a second antenna element. A dual frequency omnidirectional antenna, comprising: an opening formed in the ground conductor plate at a position between the ground conductor plate and a line for feeding the first antenna element. A first dielectric substrate facing the first dielectric substrate and a ground conductor plate provided between the first dielectric substrate and the second dielectric substrate; On the surface of the dielectric substrate opposite to the ground conductor plate, an odd-numbered first size antenna element formed from one end of the dielectric substrate, and the even-numbered first size formed first element A first array antenna comprising an antenna element having a second size different from the size of the first dielectric antenna; and an odd number counting from one end of the second dielectric substrate on a surface opposite to the ground conductor plate. A second array antenna composed of an antenna element of a second size formed on each of the first and second antennas, and a second array antenna composed of an antenna element of a first size formed on each of the even-numbered antenna elements; Of the array antennas facing each other An opening formed in the ground conductor plate at a position between antenna elements; a line feeding a first antenna element counted from one end of the first array antenna; and one of the first array antennas A line connecting an even-numbered antenna element counted from the end of the second array antenna and an odd-numbered antenna element that is one greater than the even number, and an odd-numbered antenna element counted from one end of the second array antenna and one more than the odd-numbered antenna element. A dual-frequency omnidirectional antenna, comprising: a line connecting to a large even-numbered antenna element. 3. A first and a second dielectric substrate facing each other at a predetermined interval, a ground conductor plate provided between the first and the second dielectric substrates, A first array antenna including a plurality of antenna elements of a first size formed on a surface of the dielectric substrate opposite to the ground conductor plate; and a ground conductor plate formed on the second dielectric substrate. A second array antenna formed of a plurality of antenna elements each having a second size different from the first size and formed on a surface opposite to the first array antenna, the first array antenna, and the second array antenna An opening formed in the ground conductor plate at a position between the mutually opposing antenna elements, a line feeding the first antenna element counted from one end of the first array antenna, One end of the array antenna A line connecting an even-numbered antenna element counting from the odd-numbered antenna element that is one greater than the even number, an odd-numbered antenna element counting from one end of the second array antenna, and an even number that is one greater than the odd-numbered antenna element A dual-frequency omnidirectional antenna, comprising: a line connecting to a second antenna element.