JPH08130408A - 2 dipole antenna - Google Patents

Abstract

(57) [Summary] (Modified) [Objective] To provide a 2-dipole panel antenna having a simple structure and capable of changing a matching frequency by a simple operation. [Structure] V-shaped arms 1a and 1b that can expand and contract with a constant opening angle
Fix the base part of the to the reflection panel 2, and
Two expandable dipole elements 3a and 3b are attached in parallel to a and 1b, respectively, and the two attached dipole elements 3a and 3b are attached in parallel.
The two dipole elements 3a and 3b were connected to each other by parallel conductors so as to be out of phase with each other, and one end of the parallel conductors was used as a feeding point. [Effect] Dipole elements 3a, 3b and V-shaped arms 1
It is possible to match the predetermined frequency by simply expanding and contracting a and 1b and cutting out and connecting one parallel conductor of 1/2 wavelength, and the adjustment operation becomes simple.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-dipole antenna used for transmitting television broadcasting waves.

[0002]

2. Description of the Related Art The structure of a conventional two dipole antenna is
This is as shown in FIG. The two-dipole antenna has a feeding point 13a at the center of the panel, has two dipole elements 11a and 11b, and has a 1/4 wavelength parallel conductor 1
4a and 14b allow these dipole elements 11a,
In-phase power is supplied to 11b.

[0003]

By the way, in the two-dipole antenna having the conventional structure, if the matching frequency is changed, the entire two-dipole antenna must be scaled up or scaled down. Therefore, as shown by the arrow in FIG. 9, the length of the support column 13, the antenna element 11a,
It was necessary to be able to adjust all of the length of 11b and the length of each of the support members 12 that support the antenna elements 11a and 11b.

Specifically, it is necessary to expand and contract at one position on the support column 13, four positions on the dipole elements 11a and 11b, and four positions on the support member 12 for a total of nine positions. Also, parallel conductor 1
Since 4a and 14b are fed in the center without being moved by 1/4 wavelength, the 1/4 wavelength parallel conductor 14
It is necessary to cut out two pieces of a and 14b, replace them, and connect them in the middle.

Therefore, although the structure of the antenna itself is relatively simple, there are many points to be adjusted, and there are problems that the structure becomes complicated and the adjusting operation becomes complicated to change the matching frequency. Therefore, an object of the present invention is to solve the above technical problems, and to provide a two-dipole antenna having a simple structure and capable of changing a matching frequency by a simple operation.

[0006]

A two-dipole antenna according to the present invention for achieving the above object has a base portion of V-shaped arms which can expand and contract at a constant opening angle fixed to a reflection panel. Two expandable dipole elements are attached to the arms in parallel, the two dipole elements attached in parallel are connected to each other by parallel conductors so as to have opposite phases, and one end of the parallel conductors is used as a feeding point. It is a thing.

The stretchable portion of the V-shaped arm and the stretchable portion of the dipole element can be constituted by screws or slides, for example. It is preferable that the parallel conductors are automatically expanded and contracted according to the expansion and contraction of the both arms (claim 2).

[0008]

According to the two-dipole antenna having the above structure,
In order to change the matching frequency, the two V-shaped arms are expanded and contracted, and the two dipole elements (a total of four poles) are expanded and contracted. That is, only the dipole element and the V-shaped arms are expanded and contracted.

As a result, in the present invention, the expansion / contraction adjusting portion is V
2 places on both arms and 4 places on dipole element Total 6
The number of adjustment points is reduced compared to the case where the two dipole antennas in FIG. 9 expand and contract one position of the support column 13, four positions of the dipole elements 11a and 11b, and four positions of the support member 12. be able to. Further, in the 2-dipole antenna of FIG. 9, since the parallel conductors 14a and 14b are fed in the center without being shifted by 1/4 wavelength, two 1/4 wavelength parallel conductors are cut out every time the expansion / contraction is adjusted. Need to connect. However, in the present invention, the dipole elements are connected by parallel conductors so as to have opposite phases,
Since one end of the parallel conductive wire is used as a feeding point (see FIG. 4), it is only necessary to cut out and connect one parallel conductive wire of ½ wavelength. That is, since the V-shaped span is determined each time the V-shaped arms are expanded and contracted, the parallel conductors may be cut out and used accordingly.

If the parallel conductors are automatically expanded and contracted in accordance with the expansion and contraction of both arms, the two V-shaped arms and the parallel conductive wires form a similar triangle. Therefore, if one of them is expanded or contracted by a predetermined amount, the other expansion or contraction amount is automatically determined, and the parallel conductors can be automatically adjusted.

[0011]

Embodiments will be described in detail below with reference to the accompanying drawings showing embodiments. FIG. 1 is a conceptual diagram of a two-dipole antenna of the present invention, FIG. 2 (a) is a side view, and FIG. 2 (b) is a front view. The two-dipole antenna has V-shaped arms 1a and 1b which can be expanded and contracted at a constant opening angle, and the base of the arms is fixed to the reflection panel 2. As shown in FIG. 2 (a), both arms 1a and 1b are slidable by covering a slender rod-shaped body 1-1 with a cylindrical body 1-2, respectively. Can be fixed to the desired length.

Two dipole elements 3a and 3b, which are respectively extendable and contractible, are attached in parallel to the tips of the arms 1a and 1b. Both ends of the dipole elements 3a and 3b are respectively composed of a base portion 3-1 having a female thread on the tip end surface thereof and an extension portion 3-2 having a male screw as shown in FIG. By screwing in, the length of the dipole elements 3a and 3b can be adjusted.

The two dipole elements 3a and 3b mounted in parallel are connected to each other by parallel conductors 4 as shown in FIG. 4, and one end of the parallel conductors 4 serves as a feeding point. There is. Since the parallel conductor 4 has a length of ½ wavelength, the parallel conductors 4 are connected so as to have opposite phases, and power is supplied from one end of the parallel conductor 4 to the two dipole elements 3a and 3b in the same phase. You can do it.

With the above-described structure, if the user tries to tune the two dipole antenna to a specific frequency, the parallel conductor 4 is removed and the V-shaped arms 1a,
The dipole elements 3a and 3b can be adjusted to a predetermined length by expanding and contracting the 1b to a predetermined length and rotating the respective extension portions 3-2 of the two dipole elements 3a and 3b.

Then, the half-wavelength parallel conductor 4 is cut out and wired. If the V-shaped arms 1a and 1b have a predetermined length, the distance between the dipole elements 3a and 3b, that is, the distance L between the tip portions of the V-shaped arms 1a and 1b.
Needless to say, (see FIG. 2 (a)) is automatically set to have a length of ½ wavelength.

Therefore, the entire structure of the two-dipole antenna can be changed in a similar manner even when the frequency changes. FIG. 5 is a diagram showing a structure according to another embodiment in which the total length of the parallel conductive wire 4 changes according to the expansion and contraction of the arms 1a and 1b. The parallel conductor 4 includes a parallel conductor main body 4-1 and a conductor extension plate 4-2 which engages with the tip ends of the V-shaped arms 1a and 1b.
Composed of and. Both ends of the parallel conductor main body 4-1 are formed in a flat plate and long grooves 4-3 are formed. A pin 4-4 projects from the extension plate 4-2. Since the extension plate 4-2 and both ends of the parallel conductor main body 4-1 are rubbed with each other so that the pin 4-4 engages with the long groove 4-3, The total length of the parallel conductor 4 can be freely changed while maintaining the electrical connection with the extension plate 4-2.

Therefore, it is not necessary to cut out and rewire the parallel conductors 4 as in the above-described embodiment, and the length of the parallel conductors 4 is automatically determined by expanding and contracting the V-shaped arms 1a and 1b. Therefore, the adjustment becomes easier. <Prototype example> V-shaped opening angle is 90 °, V-shaped arms 1a,
The range of expansion and contraction of 1b is converted to the distance between the reflector and the element, which is 0.
2λ−0.35λ (λ is a wavelength ≈1.5 m when the frequency is 200 MHz), and the dipole elements 3a and 3b
A 2-dipole antenna having a variable length range of 0.4λ-0.56λ was prototyped.

The frequencies 170-188 Hz and 18
The feeding frequency is changed in the range of 8-204 Hz and 201-228 Hz, and the dimensions L, H, D, and S of each part (H is the height of the dipole element from the reflection panel 2, D is the diameter of the dipole element, and S is the dipole. Element length, see Figure 2 (a))
Respectively, L = 0.5λ, H = 0.18λ, D = 0.
The impedance of the two dipole antenna was measured by adjusting 04λ and S = 0.47λ.

FIG. 6 to FIG. 8 are Smith charts showing the results of actual measurement, which are standardized with a feed line impedance of 50Ω. The smallest concentric circle in the chart is VSWR
The (voltage standing wave ratio) indicates a circle of 1.1, and VSWR increases by 0.1 as the circle increases.
At a frequency of 170-188 Hz, VSWR changed from about 1.1 to 1.15 as shown in FIG. Frequency 188
At −204 Hz, VSWR is about 1.0 as shown in FIG.
Kept 5. At frequencies 201-228 Hz, VSWR
Changed in the range of about 1.1 or less as shown in FIG.

Thus, in any frequency range, V
Since the SWR has a substantially good value, it has been proved that it is possible to cope with any frequency range by changing the overall structure of the two dipole antenna in a similar manner.

[0021]

As described above, according to the first aspect of the present invention, the dipole element and the V-shaped arms are expanded and contracted, and as for the parallel conductors, one parallel conductor of ½ wavelength is cut out and connected. Can be matched to a predetermined frequency with
A unique effect is obtained that the adjustment operation becomes easy.

In particular, according to the second aspect of the invention, the parallel conducting wire automatically expands and contracts according to the expansion and contraction of the both arms, so that the adjusting operation is further simplified.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a two-dipole antenna of the present invention.

2A is a side view of a two-dipole antenna according to an embodiment, and FIG. 2B is a front view.

FIG. 3 is a cross-sectional view showing a variable length structure of one end of a dipole element.

FIG. 4 is a connection diagram of two dipole elements mounted in parallel.

FIG. 5 is a perspective view showing a structure according to another embodiment in which the total length of the parallel conductive wire changes according to expansion and contraction of both arms.

FIG. 6 is a Smith chart showing the actual measurement result of the input impedance at a frequency of 170 to 188 Hz after the dimensions of each part of the two dipole antenna are set to the optimum values.

FIG. 7 is a Smith chart showing the actual measurement result of the input impedance at a frequency of 188-204 Hz after the dimensions of each part of the two-dipole antenna are set to the optimum values.

FIG. 8 is a Smith chart showing actual measurement results of input impedance at a frequency of 201 to 228 Hz after setting the dimensions of each part of the two-dipole antenna to optimal values.

FIG. 9 is a perspective view showing a structure of a conventional two-dipole antenna.

[Explanation of symbols]

 1a, 1b V-shaped both arms 2 Reflective panel 3a, 3b Dipole element 4 Parallel conducting wire

Front page continuation (72) Inventor Masami Sekiguchi 1-3-3 Shimaya, Konohana-ku, Osaka Sumitomo Electric Industries, Ltd. Osaka Works (72) Inventor Akira Ishii 2-2-1 Jinnan, Shibuya-ku, Tokyo Japan Broadcasting Association Broadcast Center (72) Inventor Shinichi Fujiwara 2-2-1, Jinnan, Shibuya-ku, Tokyo Inside Broadcasting Corporation Broadcast Center (72) Inventor Makoto Otani 2-2-1, Jinnan, Shibuya-ku, Tokyo Meeting Broadcast Center

Claims (2)

[Claims] 1. A V-shaped base of both arms that can expand and contract with a constant opening angle is fixed to a reflection panel, and two expandable dipole elements are mounted in parallel on the both arms and are mounted in parallel. A two-dipole antenna, characterized in that the two dipole elements are connected to each other by parallel conductors so as to have opposite phases, and one end of the parallel conductors is used as a feeding point. 2. The two-dipole antenna according to claim 1, wherein the parallel conductors are automatically expanded and contracted according to the expansion and contraction of the both arms.