JPH0983238A - Antenna system for multi-wave common use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the antenna system for multi-wave common use which has a low minimum resonance frequency, is capable of transmission reception at a broad frequency band and formed sufficiently to be a small size. SOLUTION: The multi-wave common use antenna system is provided with a skirt section 10 in which a spiral conductor element 12 is formed along a circumferential face of a conical base 11 and a top load section 20 in which a meander conductor element 22 is formed on a plane of a flat base 21 arranged in the vicinity of a top of the skirt section 10. Then the small sized system with a low resonance frequency is obtained. A ground element section with a spiral conductor element 42 formed is provided on a plane of a flat base interposed between the top load section 20 and the skirt section 10 and arranged in parallel with the top load section 20, then the frequency band is extended by connecting extension conductors with different length to each tip of plural (two) spiral conductors where other end of each circumferential side is arranged distributingly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device applied to a mobile communication system such as a mobile phone,
In particular, the present invention relates to a discone-type multi-wave shared antenna device suitable as a base station antenna to be mounted on a ceiling or the like.

[0002]

13 (a) and 13 (b) are views showing an example of a conventional antenna device of this type, which is a discon type antenna device well known as a wide band antenna. In FIG. 13A, 101 is a cone-shaped skirt element, 102 is a disk-shaped top load element, 103 is a power feed line, and 104 is a power feed point. Further, in FIG. 13B, L is the length along the conical inclined surface of the skirt element 101, and S is the radius of the top load element 102.

This discon type antenna device is a wide band antenna having a band of about 5 times the lowest resonance frequency (reference document: The Institute of Electronics and Communication Engineers, "Antenna Handbook,"
Chapter 3 Basic Antenna, Section 4 Combination Antenna, Section 6 Discon Antenna "P.128".

In the conventional discon type antenna device, the minimum resonance frequency is determined by the length L shown in FIG. 13 (b). For example, L = 35.5 cm,
If S = 11.5cm, the lowest resonance frequency is 200M
Hz (reference above). By the way, since the wavelength of the 200 MHz radio wave is 1.5 m, its quarter wavelength is 37.5.
cm. Therefore, the length of L of the antenna device needs to be adjusted to approximately ¼ of the wavelength of the radio wave having the lowest resonance frequency. Furthermore, the element 102 of the top load section
The radius S of is also related to the resonance frequency of the transmitted and received radio waves, and the minimum resonance frequency tends to increase as the value of S decreases.

[0005]

As described above, in the conventional discon type antenna device, the lowest resonance frequency of the transmitted and received radio waves is substantially determined by its shape and dimensional factors, and the lower resonance frequency is lower than that. Attempting to resonate will cause the antenna to become larger. On the contrary, if the size of the antenna is reduced, the lowest resonance frequency becomes higher than the current one, and the resonance does not occur at a low frequency. Therefore, there is a drawback that it cannot be miniaturized. That is, the conventional disc shown in FIG.
The antenna device of the N-type has a drawback that it is difficult to miniaturize it due to the correspondence with the lowest resonance frequency.

An object of the present invention is to have a low minimum resonance frequency,
It is an object of the present invention to provide a discone-type multi-wave shared antenna device capable of wideband transmission / reception, having a low height and capable of being formed in a sufficiently small size.

[0007]

In order to solve the above problems and achieve the object, the multi-wave shared antenna device of the present invention is constructed as follows. (1) In the multi-wave common antenna device of the present invention, a skirt portion in which a spiral conductive element is formed along the peripheral surface of a conical base body, and a flat plate base body disposed in the vicinity of the top of the skirt portion are provided on a plane. A top load portion having a meandering conductive element formed thereon. (2) The multi-wave shared antenna device of the present invention comprises: a skirt portion on which a spiral conductive element is formed along the peripheral surface of a conical base body; and a flat plate base body disposed in the vicinity of the top of the skirt portion. A spiral shape is formed on the flat surface of the flat plate base member which is interposed between the top load portion having the meandering conductive element and the top load portion and the skirt portion and which is arranged in parallel with the top load portion. A grounding element portion having a conductive element formed thereon. (3) The multi-wave shared antenna device of the present invention is the device according to (2) above, wherein the grounding element portion is such that a plurality of spiral conductors are multiply arranged on the plane of the flat plate base, and The base end portions of the conductors on the center side are integrally connected, and the other end portions of the conductors on the peripheral side are dispersedly arranged apart from each other, and extension conductors are connected to the dispersed distal ends. Has been done.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIGS. 1A and 1B are views showing the configuration of a discone-type multi-wave shared antenna apparatus according to a first embodiment of the present invention, in which FIG. 1A is a perspective view and FIG. 1B is a side view. As shown in the figure, the discone-type multi-wave common antenna device includes a skirt portion 10, a top load portion 20 arranged near the top of the skirt portion 10, and a top load portion 20.
A power supply line 30 in which a center conductor of one end is connected to the center of the
It consists of

The skirt portion 10 is formed by forming two spiral conductive elements 12a and 12b along the peripheral surface (either the front surface or the back surface) of a conical base body 11 made of an insulating material.

The top load portion 20 is placed on the plane of a flat plate base 21 made of a circular insulating substrate having a radius D (about 25 mm), which is arranged at a fixed distance S (about 5 to 15 mm) from the top of the skirt portion 10. , Meandering conductive element 22
Are formed. The diameter d of the top of the skirt portion 10
Is about 10 mm, the height H1 is about 45 mm, and the height H2 is about 30 mm.

FIG. 2A is a plan view of the top load portion 20, and FIG. 2B is a plan view of the skirt portion 10. As shown in FIG. 2B, the spiral conductive elements 12a and 12b have a radius R of the circumscribed circle of 1
Current path Ia smaller than / 4 wavelength and along the spiral
And the length L of Ib is about 1/4 wavelength. That is, since the small skirt portion 10 (base plate portion) can resonate, it is possible to resonate at a lower frequency even though it is a small antenna as compared with the conventional discone type antenna device. Since the currents flowing in the current paths Ia and Ib of the spiral conductive elements 12a and 12b flow while rotating as shown in the drawing, horizontal polarized waves are radiated while rotating upward in FIG.

On the other hand, as shown in FIG. 2A, the meandering conductive element 22 is formed on the plane of the flat plate substrate 21 by 800
A pair of first elements 23 capable of transmitting and receiving MH band radio waves
a, 23b, a second element 24 capable of transmitting and receiving a 1.5 GHz band radio wave, and a third element 24 capable of transmitting and receiving a 2 GHz band radio wave.
The element 25 and the element 25 are formed by a plurality of meander lines made of a conductive film.

Therefore, by adjusting the use of the gap of the meander line, it is possible to realize an electric length longer than apparent. For these reasons, it becomes possible to resonate at a low frequency as compared with the conventional discone type antenna device. In this case, the meandering conductive element 22 has a relatively narrow band, but as in the present embodiment, a plurality of elements (a pair of first elements 23a and 23b, a second element 24,
Since the third element 25) is connected, multiple resonance occurs.

FIG. 3 is a diagram showing the VSWR characteristic. As shown in the figure, multiple resonance occurs, and as a result, a wide band characteristic is obtained. Moreover, since the meandering conductive element 22 can easily achieve high density of the pattern as compared with the one using a simple linear element, it is possible to easily realize multiple resonance by a larger number of elements,
Wider band characteristics can be obtained.

Thus, in the antenna device according to the first embodiment, it is possible to realize a small antenna device having a wider band than the conventional discone type antenna device. (Second Embodiment) FIGS. 4 and 5 are views showing a discone-type multi-wave shared antenna apparatus according to a second embodiment of the present invention, and FIGS. 4 (a) and 4 (b) show the entire structure. FIG. 5A to FIG. 5C are a perspective view and a side view, and FIG. 5A to FIG. 5C are a plan view, a side view, and a resonance characteristic view showing the configuration of the main part. It should be noted that parts corresponding to those in FIGS. 1 to 3 are denoted by the same reference numerals, and redundant description of those parts will be omitted.

As shown in the figure, a grounding element portion 40 is interposed between the top load portion 20 and the skirt portion 10. The ground element portion 40 is the skirt portion 10 described above.
The spiral conductive element 42 is formed on the plane of a flat plate base body 41 made of a circular insulating substrate arranged in parallel with the top load portion 20 at the top of the.

As shown in FIGS. 5 (a) and 5 (b), the spiral conductive element 42 of the ground element portion 40 is composed of two spiral conductive elements 42a and 42b, which are doubly arranged. . The base end portions a1 and b1 of the conductors 42a and 42b on the center side are integrally joined in the vicinity of the center portion O of the flat plate base 41. In addition, each of the conductors 42
The other end portions a2 and b2 on the peripheral side of a and 42b are arranged in a mutually separated state, that is, at positions separated by 180 °. This prevents both end portions of each conductor having high impedance from affecting each other. However, in reality, due to mutual influence to some extent, the effect of double resonance is shallow, and as shown in FIG. 5C, the resonance characteristic has only one valley c, and the band is relatively narrow.

However, when the used radio wave is in the 280 MHz band, the required bandwidth is 2.2%. Therefore, even the resonance characteristic shown in FIG. 5C is sufficiently satisfied in terms of the band characteristic, so that there is no problem in transmitting and receiving in the 280 MHz band.

(Third Embodiment) FIGS. 6 and 7 are views showing a discone type multi-wave shared antenna apparatus according to a third embodiment of the present invention, and FIGS. 6 (a) and 6 (b) show the whole. 7 is a perspective view and a side view showing the configuration, and FIGS. 7A to 7C are a plan view, a side view and a resonance characteristic diagram showing the configuration of a main part.
The parts corresponding to those in FIGS. 4 and 5 are designated by the same reference numerals, and the duplicate description of those parts will be omitted.

As shown in the drawing, the dispersed distal ends of the other end portions on the peripheral side of the two spiral conductors 42a and 42b of the grounding element portion 40 interposed between the top load portion 20 and the skirt portion 10. Extension conductors 43a and 43b having lengths M and N are connected to a2 and b2, respectively.

The extended conducting wires 43a and 43b are shown in FIG. 7 (b).
As indicated by broken lines U, V, W and X, Y, Z, various modifications are conceivable as the shape and the mounting mode. By connecting the extension conductors 43a and 43b as described above, the influence between the tips a2 and b2 of the other end portion of the two spiral conductors 42a and 42b on the peripheral side having high impedance is weakened. Therefore, the effect of double resonance of both is enhanced, and the resonance characteristic has two valleys c1 and c2 as shown in FIG. 7C, and the band is widened. Therefore, transmission / reception in the 200 MHz band can be performed well.

(Example of Measured Data) FIG. 8 is a graph of FIG. 1 and FIG.
Of the antenna device of the first embodiment shown in FIG.
It is a figure which shows the measurement result of R characteristic.

As is apparent from FIG. 8, 800 MHz
Bands, 1.5 GHz band, 2 GHz band, 3 or less,
It was possible to obtain almost desired multi-resonance characteristics. 9 to 1
FIG. 2 is a diagram showing actual measurement results of radiation patterns at four design frequencies for the antenna device of the first embodiment shown in FIGS. 1 and 2. FIG. 9 shows 815 MHz, FIG.
0 is 940 MHz, FIG. 11 is 1.5 GHz, and FIG. 12 is 2
For each frequency of GHz.

As is clear from this result, at any frequency, both the E (θ) polarization component and the E (φ) polarization component in the horizontal plane and the vertical plane exhibit almost omnidirectionality. From the above, it was confirmed by experiments that this antenna device is small and has a desired VSWR characteristic and a desired radiation pattern, and is suitable as a base station antenna device to be mounted on an indoor ceiling or the like.

(Modifications) The present invention is not limited to the contents described in each of the above-described embodiments, but includes the following modifications.

A skirt portion having three or more spiral conductive elements. -A grounding element portion having three or more spiral conductive elements formed therein. A pair of first elements capable of transmitting and receiving radio waves in the 800 MHz band, a second element capable of transmitting and receiving radio waves in the 1.5 GHz band,
A skirt portion having a meandering conductive element including a third element capable of transmitting and receiving 2 GHz band radio waves and other elements.

(Summary of Embodiments) The configuration and operational effects of the multi-wave shared antenna device shown in the embodiments are summarized as follows. [1] The multi-wave shared antenna device shown in the embodiment is arranged in the vicinity of the top of the skirt portion 10 in which the spiral conductive element 12 is formed along the peripheral surface of the conical base body 11. The flat base body 21 is provided with a top load portion 20 on which a meandering conductive element 22 is formed on a flat surface.

In the above-described multi-wave antenna device, the top load portion 20 is disposed on the plane of the flat plate base 21 disposed near the top of the skirt portion 10, and the meandering conductive element 2 is provided.
2 is formed, the height is lower than that using the conventional linear element with a coil, and it can be formed in a sufficiently small size. In addition, the meandering conductive element 22 has a wide band characteristic because it has a relatively wide strip shape, and can have multiple resonances due to the presence of a plurality of meander lines as shown in the drawing. Further, since the meander lines of other frequencies can be arranged in the gaps between the plurality of meander lines, the pattern can be made denser and the space on the flat plate substrate 21 can be effectively used. Furthermore, since it is possible to realize an electric length that is longer than it appears, it is possible to resonate at a low frequency as compared with a conventional discone-type antenna device.

Since the skirt portion 10 has the spiral conductive element 12 formed along the peripheral surface of the conical base body 11, the radius R of the circumscribed circle of the spiral conductive element 12 is R.
Is less than 1/4 wavelength, and the length L along the spiral is about 1/4 wavelength. In this state, the antenna resonates at substantially the same resonance frequency as that of a conventionally known brown antenna or a disk-shaped monopole with a ground plane. Therefore, compared to the above conventional antenna,
The small ground plane (skirt) can resonate, and this also allows the antenna to be miniaturized. [2] The multi-wave shared antenna device shown in the embodiment is arranged in the vicinity of the top of the skirt portion 10 in which the spiral conductive element 12 is formed along the peripheral surface of the conical base body 11. A top load portion 20 having a meandering conductive element 22 formed on a flat surface of a flat plate base 21, and a state of being interposed between the top load portion 20 and the skirt portion 10 and parallel to the top load portion 20. The spiral conductive element 42 is placed on the plane of the flat plate base 41 arranged in
And a grounding element portion 40 formed with.

In the above multi-wave shared antenna device,
In addition to the same effect as [1], the grounding element portion 40 cooperates with the top load portion 20,
It becomes possible to resonate at a lower frequency. Therefore, it is possible to transmit and receive radio waves of a relatively low frequency in the 200 to 300 MHz band, for example. Further, as compared with the case where a matching circuit is provided in order to resonate at a relatively low frequency, there is an advantage that a certain amount of gain can be obtained by using the ground element section 40. [3] The multi-wave shared antenna device shown in the embodiment is the device described in [2] above, and the ground element section 40 is a parasitic element electrostatically coupled to the top load section 20. .

In the above multi-wave antenna device,
In addition to the same effects and advantages as in [2], the resonance occurs due to the coupling with the top load section 20 that resonates at another frequency.
A resonant element can be added without directly feeding power, and it is not necessary to provide a special connection circuit, so that the configuration is simple. [4] The multi-wave shared antenna device shown in the embodiment is the device described in [1] or [2] above, in which the meandering conductive element 22 is 800 M on the plane of the flat plate base 21.
A pair of first elements 23a capable of transmitting and receiving radio waves in the Hz band,
23b, a second element 24 capable of transmitting and receiving a 1.5 GHz band radio wave, and a third element 25 capable of transmitting and receiving a 2 GHz band radio wave formed by a plurality of meander lines made of conductive films. Has become.

In the above multi-wave shared antenna device,
In addition to providing the same effect as [1] or [2], the meandering conductive element 22 formed on the flat surface of the flat plate substrate 21.
At least 800MHz band, 1.5GHz band, 2
It becomes possible to send and receive GH band radio waves. [5] The multi-wave shared antenna device shown in the embodiment is the device according to [2] above, which is the ground element unit 40.
Are plural (for example, two) spiral conductors 42a. 42b are arranged in multiples (for example, double), and the conductors 42a. 42b the center side base end part a
1 and b1 are integrally connected, and the conductors 42a. 42b
The other end portions a2 and b2 on the peripheral side of are dispersedly arranged in a state of being separated from each other.

In the above multi-wave antenna device,
In addition to the same effect as [2], a plurality (for example, two) of spiral conductors 42a. A slight effect of multiple (for example, double) resonance due to 42b occurs. However, although the ends a2 and b2 of the high impedance conductors are separated from each other so that they do not affect each other, there is actually some mutual influence. Therefore, the effect of multiple (for example, double) resonance is relatively shallow, and the resonance characteristic has a single valley c as shown in FIG. 5C, and the band is not so wide. However, when the used radio wave is in the 280 MHz band, the required bandwidth is 2.2%, so the band characteristic is sufficiently satisfied. Therefore, also in this embodiment, it is possible to transmit and receive the radio wave in the 280 MHz band without any trouble. [6] The multi-wave shared antenna device shown in the embodiment is the device according to [2] above, wherein the ground element section 40 is provided.
Are plural (for example, two) spiral conductors 42a. 42b are arranged in multiples (for example, double), and the conductors 42a. 42b the center side base end part a
1 and b1 are integrally connected, and the conductors 42a. 42b
The other end portions a2 and b2 on the peripheral side of are dispersedly arranged in a state in which they are separated from each other, and further, at each of the dispersedly arranged tips,
A plurality (for example, two) of extension lead wires 43a and 43b are connected to each other.

In the above multi-wave antenna device,
In addition to providing the same effect as [2], the extended lead wire 43a,
By connecting 43b, the influence between the tips a2, b2 of the other end of the plurality of (for example, two) spiral conductors 42a, 42b at the high impedance peripheral side is sufficiently weakened. Therefore, the effect of multiple (for example, double) resonance is enhanced, and the resonance characteristic has a plurality of (for example, two) troughs c1 and c2 as shown in FIG. Therefore, transmission / reception in the 200 MHz band can be performed well.

[0035]

According to the present invention, it is possible to provide a multi-wave shared antenna device having the following operational effects. (a) The top load part uses the conventional linear element with a coil because the meandering conductive element 2 is formed on the flat surface of the flat plate base arranged near the top of the skirt part. The height is lower than that of, and it can be formed in a sufficiently small size. In addition, the meandering conductive element has a wide band characteristic because it has a relatively wide strip shape and can have multiple resonances due to the presence of a plurality of meander lines. Further, since it is possible to arrange meander lines of other frequencies in the gaps between the plurality of meander lines, it is possible to increase the density of the pattern and effectively use the space on the flat plate substrate. In addition, since it is possible to realize an electrical length that is longer than it appears, it is possible to resonate at a low frequency as compared with the conventional discone type antenna device. Since the skirt has spiral conductive elements formed along the peripheral surface of the conical base,
Compared with the conventional antenna, the ground plane part (skirt part) that is smaller can resonate, and the antenna becomes smaller.

(B) Since the grounding element part cooperates with the top load part, it is possible to resonate at a lower frequency, and for example, it is possible to transmit and receive radio waves of a relatively low frequency in the 200 to 300 MHz band. Compared to the case where a matching circuit is provided in order to resonate at a relatively low frequency, there is also an advantage that a certain amount of gain can be obtained by using the ground element section.

(C) By connecting the extension conductors, the influence between the tips of the other end portions on the peripheral side of the plurality of spiral conductors having high impedance is sufficiently weakened. Therefore, the effect of multiple resonance is enhanced and the band is widened. For this reason 2
Transmission and reception in the 00 MHz band can be performed well.

[Brief description of drawings]

1A and 1B are diagrams showing an overall configuration of a multi-wave shared antenna device according to a first embodiment of the present invention, in which FIG. 1A is a perspective view and FIG.
Is a side view.

FIG. 2 is a diagram showing a configuration of a main part of the multi-wave antenna device according to the first embodiment of the present invention, in which (a) is a plan view of a top load part and (b) is a plan view of a skirt part.

FIG. 3 is a diagram showing VSWR characteristics in the multi-wave shared antenna device according to the first embodiment of the present invention.

4A and 4B are diagrams showing an overall configuration of a multi-wave shared antenna device according to a second embodiment of the present invention, in which FIG. 4A is a perspective view and FIG.
Is a side view.

5A and 5B are diagrams showing a multi-wave shared antenna device according to a second embodiment of the present invention, in which FIGS. 5A and 5B are a plan view and a side view showing a configuration of a main part, and FIG. 5C is a resonance characteristic diagram. .

6A and 6B are diagrams showing an overall configuration of a multi-wave shared antenna device according to a third embodiment of the present invention, in which FIG. 6A is a perspective view and FIG.
Is a side view.

7A and 7B are diagrams showing a multi-wave shared antenna device according to a third embodiment of the present invention, in which FIGS. 7A and 7B are a plan view and a side view showing a configuration of a main part, and FIG. 7C is a resonance characteristic diagram. .

FIG. 8 is a diagram showing a result of actual measurement of VSWR characteristics of the multi-wave shared antenna device according to the first embodiment of the present invention.

FIG. 9 is a diagram showing an actual measurement result of a radiation pattern at 815 MHz for the multi-wave shared antenna device according to the first embodiment of the present invention.

FIG. 10 is a diagram showing an actual measurement result of a radiation pattern at 940 MHz for the multi-wave shared antenna device according to the first embodiment of the present invention.

FIG. 11 is a diagram showing an actual measurement result of a radiation pattern at 1.5 GHz for the multi-wave shared antenna device according to the first embodiment of the present invention.

FIG. 12 is a diagram showing an actual measurement result of a radiation pattern at 2 GHz for the multi-wave shared antenna device according to the first embodiment of the present invention.

13A and 13B are diagrams showing a schematic configuration of a multi-wave shared antenna device according to a conventional example, in which FIG. 13A is a perspective view and FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Skirt part 11 ... Conical base 12a, 12b ... Two spiral conductive elements 20 ... Top load part 21 ... Flat base 22 ... Meander conductive element 23a, 23b ... A pair of 1st element 24 ... 2nd element 25 … Third element L… Length along the spiral of the spiral conductive element S… Distance between the top of the skirt part and the top load part D… Radius of the top load part d… Diameter H1 of the top of the skirt part… Height from bottom of skirt portion to top of top load portion H2 ... Height from bottom of skirt portion to top of skirt portion Ia, Ib ... Current path 40 ... Ground element portion 41 ... Flat plate base 42 ... Spiral conductive element 42a, 42b ... Two spiral conductive elements 43a, 43b ... Two extended conductors M, N ... Length of each extended conductor

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Koichi Tsunekawa 2-10-1 Toranomon, Minato-ku, Tokyo NTT Mobile Communication Network Co., Ltd.

Claims (3)

[Claims] 1. A meandering conductive element is formed on a skirt portion on which a spiral conductive element is formed along a peripheral surface of a conical base body, and on a plane of a flat plate base body disposed near the top of the skirt portion. A discone-shaped multi-wave shared antenna device characterized by having a top load section. 2. A meandering conductive element is formed on a plane of a skirt portion having a spiral conductive element formed along a peripheral surface of a conical base body and a flat plate base body disposed near the top of the skirt portion. Interspersed between the top load part and the skirt part,
Further, a discone type multi-wave common antenna device comprising: a flat base body arranged in parallel with the top load section; and a ground element section having a spiral conductive element formed on a plane thereof. . 3. The grounding element portion is such that a plurality of spiral conductors are multiply arranged on the plane of a flat plate base, and the base end portions of the respective conductors on the center side are integrally joined, and the periphery of the respective conductors is integrated. The multi-wave shared antenna apparatus according to claim 2, wherein the other end on the side is dispersedly arranged in a state of being separated from each other, and an extension conductor is connected to each of the dispersedly arranged ends.