JP2000278025A - Multi-frequency dipole antenna device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Even if the frequency band to be used increases, a small and multiple frequency band can be shared, and one or more specific frequency bands are widened. SOLUTION: On both surfaces of a dielectric substrate 11, first dipole elements 12a and 12b which resonate at a _first frequency f1 are formed, and a cut 16 provided in the first dipole element is provided in the first dipole element. As a result, the second frequency f ₂ (f ₂ >
f ₁ ) second dipole elements 13 a and 13 b resonating at
, And similarly, the third, ‥‥, and n-th dipole elements are formed, and the first, second, third, and ‥‥ are similarly formed.
‥, of the n-th dipole element, in order to widen one or more of the frequency bands, in parallel to the dipole element above, or on the left side, or on the right or left or right side of the dipole element resonating at the frequency. Then, a parasitic element is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base station antenna device in, for example, a mobile communication system, and more particularly to a dipole antenna device sharing a plurality of frequency bands and widening a specific frequency band.

[0002]

2. Description of the Related Art Conventionally, a dipole antenna device of this type has been used for land mobile communication used for automobile cellular phones and the like in 0.8 GHz band, 1.5 GHz band and 2 GHz band.
A frequency in the z band is assigned.

In the conventional dipole antenna device used for each of the above-mentioned frequency bands, dipole elements which resonate at respective frequencies are independently arranged at different places.

[0004]

However, in the above-described conventional dipole antenna device, the interval between the dipole elements is determined by the wavelength ratio thereof, and the more the frequency band used, the more the respective elements become. You need a place to place it. For this reason, there is a problem that a wide place for arranging the respective elements is required, and a cost for securing a wide place and arranging the antenna device is high.

At the same time, the 0.8 GHz band used in mobile cellular phones and the 2 GHz band used in next-generation mobile communications have a wide bandwidth of more than 10% of the fractional band, and it is necessary to widen the bandwidth of a multi-frequency dipole antenna device. there were. In particular, there has been a demand to widen one or more specific frequency bands among multiple frequency bands.

[0006] The present invention has been made in view of such a point,
An object of the present invention is to solve the above-mentioned problems, and to reduce the size and use a large number of frequency bands even if the number of frequency bands to be used is increased, and to make a single or a plurality of specific frequency bands wider. It is to provide a device.

[0007]

In order to achieve the above object, a multi-frequency dipole antenna apparatus according to the present invention has a structure in which a plurality of n (n is a positive integer greater than 2) frequency bands are shared. A first dipole element resonating at a _first frequency f1 made of a metal foil having an arbitrary width on both surfaces of a dielectric substrate, and formed in the first dipole element by a cut provided in the element. The second frequency f ₂
A second dipole element that resonates at (f ₂ > f ₁ ), and a third frequency f ₃ (f ₃ > f ₂ ) formed in the second dipole element by a cut provided in the second dipole element A third dipole element that resonates in the following manner, and similarly, an n-th frequency f _n (f _n > f _n−1 ) formed in the ( _n−1 ) _-th dipole element by a cut provided in the element. , And the first, second, third,..., And n-th dipole elements are connected to a common feed line via respective common center feed points. And a multi-frequency dipole antenna device connected to the following.

(1) The first, second, third,...,
Of the n-th dipole element, in order to broaden one or more of the frequency bands, above the dipole element resonating at the frequency, or on the left side, or on the right side, or on the left and right sides, or on a composite side thereof, A parasitic element having a length suitable for a predetermined frequency band is disposed in parallel with the dipole element.

(2) In the above (1), the parasitic element may be provided on one or both sides of a dielectric substrate by a predetermined one of the first, second, third,..., N-th dipole elements. Is formed from a metal foil having a length corresponding to the distance between both ends of the dipole element and a certain width.

Since the present invention is configured as described above, in order to share a plurality of frequency bands, a metal foil or a band-shaped metal flat plate having an arbitrary width is provided on both surfaces of the dielectric substrate.
Among the desired multiple frequency bands, the lowest first frequency f ₁
To form a first dipole element having resonance, that is, a length of about 波長 wavelength of the frequency and an arbitrary width. A second dipole element having resonance at the next lower second frequency f ₂ , that is, having a length of about 波長 wavelength of the frequency and a width smaller than the width of the first dipole element, Is formed by cutting a certain width provided in the element.

Similarly, third and fourth dipole elements are sequentially formed on both surfaces of the dielectric substrate, so that a small multi-frequency dipole antenna which can share many frequency bands is used. The device is formed to have a small structure with a small number of parts. At the same time, among the dipole elements, above, or on the left side, or on the right side, or on the left or right side of the dipole element resonating at a specific frequency, or on a side surface that combines them, in parallel with the dipole element, from the dipole element A parasitic element having a short length of about 0.4 wavelength and spaced apart by about 1/8 wavelength of the frequency is provided to widen the frequency band of the dipole element.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. 1 and 2 are views showing an embodiment of a multi-frequency dipole antenna device according to the present invention. FIG. 1 shows 3 (the plurality n is a positive integer larger than 2; = 3) is shared, the 0.8 GHz band, 1.5 G band made of metal foil formed on both surfaces of the dielectric substrate is used.
FIG. 2 is a configuration diagram of an antenna device in which a parasitic element is disposed on the left and right side surfaces of a 0.8 GHz band and 2 GHz band dipole element in a three frequency shared dipole antenna device of a Hz band and a 2 GHz band. FIG. 3 is a configuration diagram of first, second, and third dipoles formed on both surfaces of FIG.
FIG. 2 is a diagram illustrating frequency versus return loss characteristics of the dipole antenna device of FIG. 1.

In FIG. 1 and FIG. 2, a triple-frequency dipole antenna device 10 includes first, second and third dipoles 12 and 1 formed on both surfaces of a dielectric substrate 11.
3, 14 and the parasitic element 2 disposed on the left and right sides thereof.
2a and 24a and dielectric substrates 21a and 21b on which 22b and 24b are respectively formed.

In FIG. 2, the first dipole 12
The first dipole elements 12a and 12b are separately formed at the center of both surfaces of the dielectric substrate 11 so as to resonate at a _first frequency f ₁ , for example, 0.8 GHz. For the feed lines 15a and 15b,
The first dipole elements 12a and 12b are formed at positions exactly 180 degrees about the center axis of the dipole 12, respectively. Then, and to the radiating element 12a, about 1/2 [lambda] ₁ wavelength lambda ₁ of the distance across the 12b first frequency f _1.

The second dipole 13 constituting the second dipole 13
Dipole elements 13a and 13b are formed in the first dipole elements 12a and 12b by cuts 16 provided in the U-shape in the elements 12a and 12b, respectively, and the second frequency f ₂ ( f ₂ > f ₁ ), for example,
In order to resonate at 1.5 GHz, the radiation elements 13a, 1
3b is set to about 1 / the wavelength λ ₂ of the second frequency f _2.
2λ ₂ .

The third component constituting the third dipole 14
Radiating elements 14a, 14b are formed in the second dipole elements 13a, 13b by notches 17 provided in the elements 13a, 13b in a U-shape, respectively, and a third frequency f ₃ ( f ₃ > f ₂ ), for example, 2 GHz
The distance between both ends of the radiating elements 14a and 14b is formed to be about λλ ₃ of the wavelength λ ₃ of the third frequency f ₃ so that resonance occurs.

The first, second and third dipoles 1
The first, second, and third dipole elements 12a, 13a, and 14a of one of the two feed lines 2, 13, and 14 are connected to the one feed line 1 via a common central feed point 18a.
5a, and the other first, second, and third dipole elements 12b, 13b, and 14b are connected to the other power supply line 15b via a common central power supply point 18b. I have. Reference numeral 19 denotes a grounding unit connected to the power supply line 15a.

The first, second and third dipoles 12, 13 and 14 formed on the dielectric substrate 11 are provided with a predetermined dipole in the longitudinal direction on the horizontal plane. The first and third dipoles 12 and 14 have a length slightly shorter than the distance between both ends and a certain width (for example, may be equal to the width of each of the dipoles 12 and 14), and A distance (for example, an arbitrarily determined specific distance) is set apart from the parasitic element 2 in parallel with the dipole elements 12 and 14.
Dielectric substrates 21a and 21b each having two surfaces 2a and 24a and 22b and 24b are provided. The specific distance is, for example, the first and third distances.
A distance equal to approximately １ ／ wavelength or approximately １ ／ wavelength of the resonance frequency of either dipole 12, 14 is considered.

The frequency of the three-frequency shared dipole antenna device 10, that is, the first frequency f ₁
= 0.8 GHz, the return loss characteristic in the second frequency f ₂ = 1.5 GHz, and the third frequency f ₃ = 2 GHz, as shown in FIG. 3, the first frequency f ₁ and the third At a frequency f ₃ of, a wide band characteristic is obtained.

In the present embodiment, the predetermined dipole whose band is to be widened is determined by the first and third dipoles 12,
14 has been described, but the predetermined dipole is replaced with the first, second and third dipoles 12, 1
3 and 14, the dielectric substrate 21
Two parasitic elements may be formed on one surface of each of a and 21b in parallel in the vertical direction.

The above-mentioned three-frequency shared dipole antenna device 1
Regarding 0, the feeder line can connect and configure a balanced circuit as well as a microstrip line of a balanced-unbalanced conversion circuit and an unbalanced circuit.

FIG. 4 shows another example of the present embodiment, in which 0.8 GHz band made of metal foil formed on both surfaces of a dielectric substrate,
FIG. 1 is a configuration diagram of a 1.5 GHz band and 2 GHz band three-frequency shared dipole antenna device in which parasitic elements are respectively disposed on the left side and above the dipole element. The same reference numerals are given and the description is omitted.

In FIG. 4, the three-frequency dipole antenna device 30 includes, as parasitic elements, the parasitic elements 22a and 24a formed on the dielectric substrate 21a on the left side, and the first and second parasitic elements. Dielectric substrate 11 on which second and third dipoles 12, 13, 14 are formed
Above, the parasitic element 31 formed above the dipoles 12, 13, 14 is provided.
These parasitic elements 22a, 24a, 31
The effect of the above is that each of the parasitic elements 22a, 24
a and 22b, 24b.

In the above embodiment, the case where the plurality n = 3 has been described.
This is a larger positive integer frequency, and is applied to more frequencies including 2 if a plurality of dipole elements can be sequentially formed in the first dipole element.

Note that the technology of the present invention is not limited to the technology in the above-described embodiment, but may be implemented by means of other modes that perform the same function. Can be changed or added.

[0026]

As is apparent from the above description, the present invention
According to the multi-frequency dipole antenna device, a plurality of
Any width on both sides of the dielectric substrate to share the waveband
The first frequency f₁Resonate with any
Forming a first dipole element having a width;
In the ipole element, a notch provided in the element
And a second dipole element having a width smaller than that of the first dipole element.
Frequency f of 2_Two(F_Two> F ₁) The second dipole resonating with
A second dipole element, and the element is formed in the second dipole element.
The second dipole element
Frequency f having a width smaller than the width of_Three(F_Three> F_Two)
To form a third dipole element that resonates at
Forming an n-th dipole element,
The first, second, third,..., N-th dipole elements are
Via a common central feed point to a common feed line
Connected, and among the dipole elements,
To widen one or more of the frequency bands,
Above or to the left of the dipole element resonating in number,
Or, on the right or left and right sides,
The frequency used is
Even if the band increases, it is small and can share many frequency bands.
You. For example, for a base station in a mobile communication system,
Frequency band such as 0.8GHz, 1.5GHz, 2GHz
And miniaturization of the dipole antenna device
In the plurality of frequency bands, one or more
Frequency band can be broadened.
I do.

When there are a plurality of frequency bands to be broadened, the entire structure can be simplified by forming the parasitic element from a metal foil formed on both surfaces of the dielectric substrate. That is, for example, for a base station in a mobile communication system, 0.8 GHz, 1.5 GHz, 2 GHz
It is possible to widen the bandwidth of a multi-frequency dipole antenna device in the Hz band. The present invention can of course be applied to two frequencies, for example, the 0.8 GHz and 1.5 GHz bands.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of a multi-frequency dipole antenna device according to the present invention, in which a three-frequency dipole antenna device formed on both surfaces of a dielectric substrate has no feed in the front-rear direction of a two-frequency dipole element. FIG. 3 is a configuration diagram of an antenna device provided with elements.

FIG. 2 is a configuration diagram of an antenna device having first, second, and third dipoles formed on both surfaces of a dielectric substrate.

FIG. 3 is a characteristic diagram of frequency versus return loss of the dipole antenna device of FIG. 1;

FIG. 4 shows another example of the embodiment of FIG. 1, in which a three-frequency dipole antenna device is formed on both surfaces of a dielectric substrate, and parasitic elements are disposed on the left side and above the dipole element, respectively. FIG. 2 is a configuration diagram of a completed antenna device.

[Explanation of symbols]

10, 30 Tri-frequency shared dipole antenna device 11, 21a, 21b Dielectric substrate 12 First dipole 12a, 12b First dipole element 13 Second dipole 13a, 13b Second dipole element 14 Third dipole 14a, 14b Third dipole element 22a, 22b, 24a, 24b, 31 Parasitic element f ₁ First frequency f ₂ Second frequency f ₃ Third frequency

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshio Ebine F-term in NTT Mobile Communication Network Co., Ltd. 2-10-1, Toranomon, Minato-ku, Tokyo 5J046 AA03 AA07 AB01 AB07 PA07 TA03 UA01

Claims (2)

[Claims] 1. A plurality n (n is a positive integer greater than 2)
To share the same frequency band,
A first frequency f made of a metal foil having a width ₁Resonates with
A first dipole element, and inside the first dipole element
A second notch formed by a cut provided in the element.
Frequency f_Two(F_Two> F₁The second dipole resonating with
And an element provided in the element in the second dipole element.
Frequency f formed by the cut notch_Three(F_Three>
f_TwoA) a third dipole element that resonates in the same manner;
N-th frequency f formed by the provided cuts_n
(F_n> F_n-1) And the n-th dipole element that resonates
And the first, second, third,.
Dipole elements go through their common central feed point
Multi-frequency dipole connected to a common feed line
, The first, second, third,..., N-th dipole elements
Of these, one or more of the above-mentioned frequency bands are expanded.
The dipole element resonating at the frequency for banding
Above, or on the left, or on the right, or on the left or right
In parallel with the dipole element,
Characterized in that a parasitic element having a length of
Multi-frequency dipole antenna device. 2. The distance between two ends of a predetermined dipole element among the first, second, third,..., And n-th dipole elements on one or both sides of a dielectric substrate. 2. The multi-frequency shared dipole antenna device according to claim 1, wherein the multi-frequency shared dipole antenna device is formed of a metal foil having a length corresponding to the following and a certain width.