JP2000183633A - Dipole antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the reliability of a dipole antenna by simplifying a structure, reducing cost and enhancing accuracy of the relative position of both antenna elements in the dipole antenna, where a 1st antenna element supplying an AC current and a 2nd antenna element connected to ground are relatively placed. SOLUTION: First antenna elements U1, U2 are configured with conductor pieces, 2nd antenna elements D1, D2 are configured with a conductor pattern connected to a ground 3 of a board 1 and the 1st antenna elements are fixed to the board 1 by screws N1, N2. The output terminal of a radio section 2 formed on the board 1 is connected to the 1st antenna elements via wires 4, 5 and an AC current is supplied to the 1st antenna elements. The conductor pattern of the 2nd antenna elements is configured to be a strip line so as to reduce a length of the conductor pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dipole antenna in which a first antenna element to which an alternating current is supplied and a second antenna element connected to a ground are opposed to each other. The present invention relates to a dipole antenna that realizes enhancement of the reliability of the antenna by being configured as a conductor pattern on a substrate.

[0002]

2. Description of the Related Art A dipole antenna is used as an antenna of a radio equipment such as a mobile station of a mobile communication system. FIG. 4 shows an example of the structure of a dipole antenna. As shown in the figure, the dipole antenna has a structure in which, for example, two antenna elements 21 and 22 composed of linear conductor pieces having the same length are arranged to face each other. Here, each antenna element 21,
It is known that the length of 22 is preferably, for example, １ ／ of the wavelength of a signal (electromagnetic wave) used for communication.

The above-mentioned dipole antenna is connected to, for example, an output terminal of a radio device. As an example, a feeder 23 is connected to one end of one antenna element (for example, upper element) 21 to supply an alternating current. In addition, with the configuration in which the grounding part is connected to one end of the other antenna element (for example, lower element) 22, wireless communication can be performed by the dipole antenna. Note that, for example, a coaxial cable can be used as a connection line connecting the wireless device and the dipole antenna.

[0004]

However, the structure of the dipole antenna as described above requires two antenna elements composed of conductor pieces having a mechanical structure as shown in FIG. In general, in a dipole antenna, it is necessary to accurately set the relative positions of the two antenna elements. However, in the above-described structure, since the two antenna elements are formed of separate conductor pieces, the relative positions of the two antenna elements are determined. It was difficult to set accurately, for example, it took a lot of cost and time. For this reason, in the conventional dipole antenna, for example, the cost for configuring the antenna is high, and it is difficult to accurately position both antenna elements as described above, so that the reliability of the antenna is low. There is a problem that the performance is reduced (that is, the function does not function as desired).

The present invention has been made to solve such a conventional problem, and a first antenna element to which an alternating current is supplied and a second antenna element connected to a ground portion are disposed so as to face each other. It is an object of the present invention to provide a technique for realizing, for example, the reliability of the dipole antenna.

[0006]

In order to achieve the above object, in a dipole antenna according to the present invention, a first antenna element to which an alternating current is supplied and a second antenna element connected to a ground are provided.
In a configuration in which the antenna element is disposed so as to be opposed to the first antenna element, the first antenna element is formed of a conductor piece, while the second antenna element is formed of a conductor pattern connected to a ground portion of the board, and the first antenna element is formed of the board. Fixed to.

Therefore, the second antenna element is configured as a conductor pattern on the substrate, and the grounding part of the substrate is used as a grounding part connected to the second antenna element.
For example, the structure of the antenna can be simplified and the cost can be reduced. In addition, since the first antenna element has a structure in which the first antenna element is fixed to the above-described substrate with screws or the like, the first antenna element
It becomes easy to set the relative position between the antenna element and the second antenna element with high accuracy, and thereby, for example, the reliability of the antenna can be greatly improved as compared with a dipole antenna using a conventional structure.

If, for example, the first antenna element is configured as a pattern on the substrate, the electromagnetic field (radio signal) radiated from the first antenna element or the like is blocked by the substrate and the like. However, in the present invention, since the first antenna element to which the alternating current is supplied is formed of a conductor piece as described above, the directivity of the first antenna element is reduced. It can be isotropic or nearly isotropic.

Further, the dipole antenna of the present invention may be used, for example, as a transmitting antenna, may be used as a receiving antenna, or may be used as a shared antenna for transmitting and receiving. During transmission, for example, an alternating current is supplied from a power supply unit such as a wireless device to the first antenna element. At the time of reception, for example, the effect of an electromagnetic field (radio signal) radiated into space from another wireless device is reduced. The AC current is fed (induced) to the first antenna element by receiving the one antenna element.

[0010] In the dipole antenna according to the present invention, the conductor pattern of the second antenna element is formed of a strip line. Here, when a signal is transmitted by a strip line (strip line), the wavelength of the signal can be substantially shortened as compared with a case where the signal is transmitted by a simple conductor pattern.

Therefore, by forming the conductor pattern of the second antenna element from the strip line as described above, the length of the conductor pattern can be shortened as compared with the case where the conductor pattern is constituted by a simple conductor pattern. Specifically, as described above, for example, in a dipole antenna, the first
The length of the antenna element or the second antenna element is set to one of the signal wavelengths.
Although it is preferable to be about / 4, by using a strip line as the second antenna element, the conductor pattern of the second antenna element can be shortened and the antenna can be downsized.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described with reference to the drawings. FIG. 1 shows an example of a dipole antenna according to the present invention. FIG. 1 shows an example in which two dipole antennas are formed on one substrate 1. That is, the substrate 1 shown in FIG. 1 includes, for example, an antenna element (referred to as an “upper element”) U1 composed of a linear conductor piece and a linear conductor pattern formed on the substrate 1. A first dipole antenna in which a configured antenna element (referred to as a “lower element” in this example) D1 is disposed so as to face the same, and an antenna element (upper element) U2 similarly configured from a linear conductor piece and A second dipole antenna in which an antenna element (lower element) D2 formed of a linear conductor pattern formed on the substrate 1 is arranged so as to be opposed to the antenna element (lower element) D2.

In this embodiment, since the first and second dipole antennas have the same configuration, the dipole antennas will be described together. The upper elements U1 and U2 have, for example, one end fixed to the substrate 1 by metal screws N1 and N2, and the other end disposed outward of the substrate 1, and the one end (in this example, the screwed portion). ), The output end of the radio unit 2 formed on the substrate 1 is connected via wirings 4 and 5.

One end of each of the lower elements (ground wires) D1 and D2 is connected to, for example, a ground portion 3 provided on the substrate 1, and the other end is located inside the substrate 1 (ie, opposite to the upper elements U1 and U2). Direction).
In this example, the lower elements D1 and D2 and the grounding portion 3
Are formed as a common ground (GND) pattern. In FIG. 1, the ground pattern is indicated by oblique lines to make it easier to see. In this example,
The above-mentioned grounding unit 3 is also used for grounding the radio unit 2.

In a preferred embodiment of the present invention, each of the antenna elements U1, U2, D1, and D2 is a half-wavelength dipole antenna having a length (1/4) of a wavelength (λ) of a signal (electromagnetic wave) used for communication. Is configured. In the dipole antenna of the present example having the above configuration, for example, the upper elements U1 and U2
By supplying an alternating current to the antenna, radio transmission from the antenna can be performed. For example, a radio signal received by the antenna is transmitted as an alternating current from the upper elements U1 and U2 to the radio unit 2 , Wireless reception by the antenna can be performed.

In FIG. 1, the lower element D
Although an example is shown in which 1, D2 is constituted by, for example, a simple conductor pattern layer, a strip line structure can be used as the conductor pattern. FIG. 2 shows a structural example of a dipole antenna using such a strip line. In the example of FIG. 2, for example, lower elements D3 and D4 are constituted by strip lines formed on the substrate 11. Except for this point, the configurations of the substrate 11, the radio unit 12, the grounding unit 13, the wirings 14, 15, the upper elements U3, U4, and the screws N3, N4 are the same as those shown in FIG.

Here, a strip line is generally known as a line that transmits using a pair of metal plates, and the wavelength of a signal transmitted in the line is caused by the effect of a dielectric material buried between the metal plates. Is substantially shorter than, for example, the wavelength in free space. In this example, as an example, the above-described substrate 11 is used as the dielectric, and the substrate 1
By using the dielectric constant of 1, it is possible to substantially shorten the signal wavelength, whereby, for example, compared to the case of using a simple conductor pattern as shown in FIG.
The length (electric length) of the lower elements D3 and D4 is reduced.

Specifically, in the case of this example, the length (L) of the lower elements D3 and D4 can be made shorter than the length of 1/4 of the signal wavelength used for communication. Even in a configuration using a line, for example, wireless communication can be performed in the same manner as in the case of the dipole antenna shown in FIG.

FIG. 3 shows an example of a directivity pattern of the half-wavelength dipole antenna shown in FIG. 1 as an example of a directivity pattern as an example of the directivity pattern of the dipole antenna according to the present invention. FIG. 3A shows the horizontal directivity, and FIG. 3B shows the vertical directivity. 1A and 1B show an example of the appearance of an antenna unit A in which two dipole antennas on the substrate 1 shown in FIG. 1 are packaged into one unit.

FIGS. 3A and 3B show the maximum (Max), minimum (Min) and average (Av) values of the lower element length and the directivity pattern set at the time of measurement.
g), and as the lower element length, “ORIGINAL” in the figure indicates a length of １ ／ of the signal wavelength, and a deviation from this length is indicated by “+1 cm” or the like. is there.

In the dipole antenna of the present embodiment, as an example, wireless communication can be performed by using the directivity patterns shown in FIGS. 3A and 3B. In addition,
As described above, even in the case of the dipole antenna using the stripline shown in FIG. 2, wireless communication can be performed with a similar directivity pattern.

As described above, in the dipole antenna of the present embodiment, the first antenna element (upper elements U1 to U4 in the present embodiment) to which an alternating current is supplied is formed of a conductor piece, and is connected to the ground. Since the second antenna element (the lower elements D1 to D4 in this example) is formed of a conductor pattern connected to the ground portion of the substrate, and the first antenna element is fixed to the substrate, the two antenna elements are arranged facing each other. For example, the structure can be simplified by forming the second antenna element from a conductor pattern and the like, and since both antenna elements are integrally fixed by the same substrate, the relative The position can be set with high accuracy, and the assemblability of the antenna can be improved.

Specifically, for example, the lower elements D1 to D1
Substrates 1 and 11 are configured as a grounding portion for connecting D4 to the lower elements D1 to D4 while constituting D4 from a conductor pattern.
Since the grounding portions 3 and 13 are used, the configuration of the lower elements D1 to D4 can be simplified and the cost can be reduced. As an example, in this example, the substrate 1,
11 shows the shape of the ground pattern formed in FIG.
The lower elements D1 to D4 can be easily configured by forming the shape as shown in FIG.

If a dipole antenna is formed by using the substrates 1 and 11 on which the radio units 2 and 12 are formed as in this embodiment, the substrate 1 is composed of the radio units 2 and 12 and the dipole antenna. , 11 and the grounding portions 3 and 13 can be shared, so that the structure can be further simplified and the cost can be reduced.

Since the upper elements U1 to U4 are fixed to the substrates 1 and 11 on which the lower elements D1 to D4 are formed as conductor patterns by screws or the like, the upper elements U1 to U4 and the lower elements D1 to D4 It is easy to set the relative position of the antenna with high accuracy, and thereby it is easy to increase the accuracy and increase the reliability such as the directivity of the antenna. In the configuration in which the upper elements U1 to U4 are fixed to the substrates 1 and 11 with screws or the like as in this example, the arrangement of the upper elements U1 to U4 can be easily adjusted by adjusting the screws or the like. .

Further, since the upper elements U1 to U4 are not formed as patterns on the substrate but made of conductor pieces, for example, the directivity around the upper elements U1 to U4 isotropically or substantially isotropic. And an antenna unit A such as shown in FIG.
, It is possible to provide a practically effective configuration in which the substrates 1 and 11 are provided inside the package and the upper elements U1 to U4 are provided outside the package.

Further, since the lower elements D1 to D4 are constituted by the conductor patterns on the substrates 1 and 11, for example, a plurality of dipole antennas (two in this example) are connected to the same substrate 1 as in this example. The antenna unit A and the grounding units 3 and 13 can be used in common, so that the antenna unit A can be made compact and the cost can be reduced.

In the dipole antenna of the present embodiment, the second antenna element (the lower element D in this embodiment) is used.
By forming the conductor pattern of (3, D4) from a strip line, the length of the second antenna element (that is, the strip line) can be reduced as compared with a case where a simple conductor pattern is used. Specifically, for example, when it is necessary to reduce the size of the substrate, and a portion formed on the substrate cannot be secured with a mere conductor pattern, the second antenna element should be formed of a strip line. Thus, the required size of the substrate (for example, the size corresponding to the length direction of the strip line) can be reduced.

As described above, in the dipole antenna of this embodiment, for example, the structure of the antenna can be simplified,
It is possible to increase the reliability of the antenna, to reduce the cost of the antenna and to improve the economic efficiency, and to achieve a very large effect in practical use.

Here, the second antenna element of the dipole antenna according to the present invention (the lower element D in the above embodiment)
A variety of substrates may be used as the substrate that constitutes (1) to (D4). For example, a printed substrate (P / B: Printe
d Board) can be used. Further, there is no particular limitation on the method of fixing the first antenna element (the upper elements U1 to U4 in the above embodiment) to the substrate, and the screw shown in the above embodiment may not necessarily be used.

The structure of the dipole antenna, such as the shape (length and the like) of each antenna element and the arrangement of the first antenna element and the second antenna element, are not necessarily limited to those described in the above embodiment. For example, various configurations may be used as long as they have a function as an antenna in practical use. The field to which the dipole antenna according to the present invention is applied is not particularly limited, and the present invention can be applied to an antenna of a wireless device such as a mobile station of a mobile communication system.

[0032]

As described above, according to the dipole antenna of the present invention, the first antenna element to which the AC current is supplied is constituted by the conductor piece, while the second antenna element connected to the ground is formed by the substrate. Since the first antenna element is fixed to the substrate and the two antenna elements are arranged so as to face each other, for example, the structure of the antenna is simplified and the cost is reduced. Also, for example, the accuracy of the relative position between the first antenna element and the second antenna element can be improved, so that the reliability of the antenna can be improved.

Further, in the dipole antenna according to the present invention, the conductor pattern of the second antenna element is formed of a strip line, so that the length of the conductor pattern is reduced as compared with the case where the conductor pattern is formed of a simple conductor pattern. Therefore, for example, the size of the antenna can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structural example of a dipole antenna according to one embodiment of the present invention.

FIG. 2 is a diagram showing another structural example of a dipole antenna according to one embodiment of the present invention.

FIG. 3 is a diagram showing an example of a directivity pattern of a dipole antenna according to one embodiment of the present invention.

FIG. 4 is a diagram showing a structural example of a dipole antenna according to a conventional example.

[Explanation of symbols]

1, 11, board, 2, 12, radio section, 3, 1
3, grounding part, 4, 5, 14, 15, wiring, U1
Upper element, D1 to D4, lower element, N1 to N4 screw, A, antenna unit,

Claims (2)

[Claims] 1. A dipole antenna in which an AC current-supplied first antenna element and a second antenna element connected to a ground portion are arranged to face each other. A dipole antenna, wherein the two antenna elements are formed of a conductor pattern connected to a ground portion of a substrate, and the first antenna element is fixed to the substrate. 2. The dipole antenna according to claim 1, wherein the conductor pattern is formed of a strip line.