JPH07263945A - Directional variable helical antenna system - Google Patents

Abstract

PURPOSE:To provide the directional variable helical antenna system which mechanically and electrically varies a beam to surely track the radio wave of a satellite or the like. CONSTITUTION:An antenna element (conductor wire) 2 whose radius is sufficiently smaller than the reception wavelength is wound around a columnar member 1 by n turns to constitute a bifilar helical antenna. This antenna element 2 has the terminal end (lower end) short-circuited and is fed from the front end (upper end). Phase varying parts 3 are loaded in the center and on and under the center of the columnar member 1 at intervals of 1/2 turn of the antenna element 2, and length L[m] of phase varying parts 3 is changed to change the amplitude phase or the current distribution on the antenna element 2. Length L of phase varying parts 3 is adjusted to change the current distribution, thus giving a variable directivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a directional variable helical antenna device used for mobile communication, especially for mobile phones for ships and automobiles.

[0002]

2. Description of the Related Art Conventionally, mobile communication such as communication with a fixed station has been used in mobiles such as ships, aircrafts and automobiles. In this mobile communication, ships of the type in which an antenna element is fixed and equipped are generally used.

[0003]

However, the conventional type in which the antenna element is fixedly mounted as described above is
There is a problem that the directivity of the antenna changes due to rolling and pitching of the sea surface, and the beam does not point in the desired direction.

On the other hand, there is a phased array antenna as an antenna capable of directing a beam in a desired direction. However, this antenna is not suitable for versatility because of an expensive system and a complicated circuit configuration.

The present invention has been made in view of the above circumstances, and provides a variable directivity helical antenna device capable of mechanically and electrically varying a beam and reliably tracking a radio wave from a satellite or the like. The purpose is to

[0006]

[Means for Solving the Problems]

(1) A variable directivity helical antenna device according to the present invention includes a helical antenna and a phase variable section provided in the central portion of the element of the helical antenna, and the directivity is changed by setting the phase in the phase variable section. It is characterized by

(2) Further, the variable directivity helical antenna device according to the present invention comprises a helical antenna element formed by winding a plurality of conductor wires in a cylindrical shape having an arbitrary diameter and at an equal pitch. The antenna element is provided with a means for variably setting the number of turns N with a constant diameter of the antenna element, and the directivity is varied by variably setting the number of turns N of the antenna element.

[0008]

By providing a phase variable portion in the central portion of the element of the helical antenna and variably setting the phase with this phase variable portion, the current distribution and directivity can be controlled. Therefore, the antenna beam can be moved up and down according to the change of the latitude of the moving body, and it can be used in a wide range.

Further, by providing a means for variably setting the number of turns N while keeping the diameter of the helical antenna constant, the elevation angle of the antenna beam can be varied. Therefore, the helical antenna according to the present invention can be used as an antenna for tracking a moving body in which the elevation angle of the beam can be tilted within the range of use, or can be attached to the moving body for use.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a structural diagram of a bifilar helical antenna according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a columnar member made of an insulating material, and an antenna element (conductor wire) 2 having a radius sufficiently smaller than a reception wavelength is wound around the columnar member 1 n times to form a bifilar helical antenna. . The antenna element 2 has a structure in which the terminal (lower end) is short-circuited and power is supplied from the tip (upper end). The cylindrical member 1 has, for example, a helical overall length (height) H of 0.813 [m] and a diameter D of 0.019.
The size is set to [m].

The phase varying portion 3 is loaded on the central portion of the columnar member 1 and above and below it for each 1/2 turn of the antenna element 2, and the length L [m] of the phase varying portion 3 is changed to change the antenna. It is configured so that the amplitude and phase of the current distribution on the element 2 can be changed. By adjusting the length L of the phase varying section 3, it is possible to change the current distribution and provide variable directivity. Although FIG. 1 shows the case where three phase changing parts 3 are provided, the number of phase changing parts 3 can be set to one or more, and any number can be set.

The phase varying section 3 is specifically constructed as shown in FIGS. 2 (a) and 2 (b), for example. Figure 2 (a)
Shows an example in which the phase varying unit 3 is configured in a trombone type. That is, the phase varying section 3 is composed of a large-diameter first antenna element 11 formed in a hollow cylinder shape and a small-diameter second antenna element 12 inserted inside the first antenna element 11. There is. The second antenna element 12 is movably provided in the first antenna element 11 with some resistance, and when the movement operation is stopped at an arbitrary position, the position with respect to the first antenna element 11 is changed. It is designed to be held stably.

In FIG. 2A, the amplitude L of the current distribution on the antenna element 2 is changed by adjusting the length L of the phase varying unit 3.
In addition, as shown in FIG. 2B, a varactor diode 13 may be provided in the phase variable unit 3 and its capacitance may be changed to change the amplitude and phase of the current distribution on the antenna element 2. .

That is, the varactor diode 13 is provided between the first antenna element 11 and the second antenna element 12, and the DC power supply 14 is supplied to both ends of the varactor diode 13 via the voltage variable circuit 15. This voltage variable circuit 15 is, for example, DC
A DC converter is used to convert the output voltage of the DC power supply 14 into an arbitrary set voltage and supply it to the varactor diode 13. Further, a feedthrough capacitor 16 for blocking a DC voltage is provided between the first and second antenna elements 11 and 12 and the adjacent antenna element.

The capacitance of the varactor diode 13 changes according to the voltage supplied from the voltage variable circuit 15. Therefore, the amplitude and phase of the current distribution on the antenna element 2 can be changed by the value of this capacitance, and variable directivity can be obtained.

In the helical antenna constructed as described above, the total helical length H of the cylindrical member 1 is 0.813.
[M], the diameter D is 0.019 [m], and the phase variable unit 3
Length L of "0m", "0.05m", "0.10
m ”, the number of turns N of the antenna element 2 is“ 3 ”,“ 7 ”,
Current distribution, input impedance when "14" is set,
Various characteristics such as directional characteristics and gain are shown in FIGS.

The current distribution in FIG. 3 has a solid line of 1.5350.
[GHz] and the broken line is 1.6435 [GHz],
The number of expansion functions on the horizontal axis, that is, the helical length (m),
The vertical axis shows the current amplitude (A). As can be seen from FIG. 3, when “L = 0”, the current distribution shows a standing wave distribution, but when “L = λ / 8” or more, it has a traveling wave distribution characteristic.

FIGS. 4A and 4B show the input impedance characteristics of the receiving helical antenna, and FIGS. 5A and 5B show the input impedance characteristics of the transmitting helical antenna. As can be seen from the figure, even if the length L of the phase varying section 3 is changed, the resistance component changes only about 160Ω to 300Ω.

6 and 7 show the radiation directivity (vertical directivity) of the helical antenna. When the length L of the phase varying unit 3 loaded on the antenna element 2 is zero, the beam directed in the zenith direction tilts due to the change of the length of L, and the beam has a large ground angle. You can see that it changes.

FIG. 8 shows the gain characteristics of the above helical antenna. A gain of about 9.8 dB is obtained when "L = 0.05 m". As described above, the current distribution and directivity can be controlled by providing the phase variable section 3 in the central portion of the antenna element 2. Therefore, the beam can be moved up and down according to the change in the latitude of the moving body, and can be used in a wide range.

(Second Embodiment) FIG. 9 is a structural diagram of a helical antenna according to a second embodiment of the present invention. As shown in the figure, for example, the antenna element (conductor wire) 22 is provided N times, for example, 5 to 5 on a cylindrical member 21 having a helical total length (height) H of about 3 [λ] and a diameter D of 0.095 [λ]. A bifilar helical antenna is constructed by winding 7 times. The antenna element 22 has a terminal end (lower end) short-circuited and power is supplied from the tip end (upper end). The columnar member 21 has a configuration in which the number of turns of the antenna element 22 can be changed by, for example, 0.5 to 1.5 turns.

The helical antenna shown in FIG. 9 is specifically constructed as shown in FIGS. 10 and 11, for example. FIG. 10: is a perspective view which shows the whole structure, FIG.
(C) is a block diagram showing an exploded view.

In FIG. 10, 23 is an antenna base,
The antenna unit 24 is provided on the antenna base 23. The antenna section 24 has an antenna element 22 provided in an external protective cylinder 25, and a winding number adjusting knob 31 provided at an upper end portion. The winding number adjusting knob 31 is provided.
The number of turns N of the antenna element 22 can be adjusted, for example, in the range of 5 to 7 times by rotating. The antenna section 24 is configured as shown in FIG.

FIG. 11A shows the external protection cylinder 25 of the antenna section 24. On the inner wall of the outer protective cylinder 25,
A plurality of holding members 26 are provided in the vertical direction, and the holding members 26 hold the element rotating mechanism and the element unit shown in FIG. 11B.

In FIG. 11 (b), 27 is an outer cylinder, which is a guide groove 28a in the shape of an arc that is oblique along the wall surface thereof.
28b are provided at an interval of 180 °. Also, 2
Reference numeral 9 is an inner cylinder that is inserted into the outer cylinder 27, and vertical guide grooves 30a and 30b are provided on the wall surface thereof at an interval of 180 °. On the upper part of the inner cylinder 27, a knob 31 for adjusting the number of turns is provided.

The antenna member 3 is provided in the inner cylinder 29.
2 is inserted. The antenna member 32 includes an element holding cylinder 33 and an element portion 34. The element holding cylinder 33 has guide projections 35a and 35b on the outer peripheral surface thereof.
It is provided with an interval of 0 °. This guide projection 35
a and 35b are the guide grooves 30a and 3 of the inner cylinder 29.
0b and the guide grooves 28a, 28b of the outer cylinder 27. The upper end of the element portion 34 is mounted on the element holding cylinder 33. This element portion 34 is shown in FIG.
A plurality of, for example, two antenna elements 22 are attached to the film-shaped insulating member 36 as shown in FIG. Further, the element mounting member 3 is provided on the upper and lower ends of the film-shaped insulating member 36.
7a to 37c are provided. In this case, the distance between the element mounting members 37a and 37c located on both sides is set to "πD", and the element portion 34 is rolled into a cylindrical shape to hold the element holding cylinder 3
The element mounting members 37a and 37c are arranged so as to overlap each other when they are mounted on the substrate 3. The width of the film-shaped insulating member 36 is set to "πD + α" so that both side edges of the film-shaped insulating member 36 partially overlap when the element portion 34 is attached to the element holding cylinder 33.

The element portion 34 includes guide projections 35a,
35b is inserted into the guide grooves 30a and 30b of the inner cylinder 29 and the guide grooves 28a and 28b of the outer cylinder 27, and is housed and fixedly held in the outer protective cylinder 25. The lower end portion of the element portion 34 is the external protection cylinder 25.
And the lower end of the antenna base 23 are fixed to the upper end of the antenna base 23 shown in FIG. In this case, the element portion 34 is mounted on the antenna base portion 23 in a state where the antenna element 22 is helically wound 5 to 7 times. That is, the antenna element 22
Is wound into a cylindrical shape having a diameter D and is helically wound a plurality of times at an arbitrary equal pitch.

In the antenna section 24 constructed as shown in FIG. 11, when the winding number adjusting knob 31 is turned, the guide projection 35a of the antenna member 32 inserted in the guide grooves 30a and 30b of the inner cylinder 29 is formed. , 35b receive a lateral force and move obliquely upward or downward along the guide grooves 28a, 28b of the outer cylinder 27. As a result, the antenna member 3 is adjusted according to the operation amount of the winding number adjusting knob 31.
2 rotates, and the number of turns of the antenna element 22 changes. In this case, the diameter D of the element portion 34 is always kept constant even if the number of turns is changed by operating the number-of-turns adjusting knob 31. The maximum change amount of the number of turns of the antenna element 22 can be set by the length of the guide grooves 28a and 28b with respect to the outer cylinder 27. Usually, the maximum change amount of the number of turns of the antenna element 22 is set to about 0.5 to 1.5 turns.

In the above helical antenna, the total helical length H is about 3 [λ] and the diameter D is 0.095 [λ],
The radiation directivity when the number of turns N is changed is shown in FIG.
It shows in (b). As can be seen from FIG. 12, “N = 5 to 5”
The beam elevation angle is 30 °-
It can be seen that it is inclined to the 65 ° use range. That is, it can be seen that the ground angle of the beam changes by changing the number of turns while keeping the total length and diameter constant.

FIG. 13 shows the frequency characteristic of the gain of the above antenna, which shows a constant value of about 7.8 dBi. When the number of turns increases, the beam (pencil beam) is directed in the zenith direction, and the gain increases.

In FIGS. 14A and 14B, the number of turns N is "N =
5 shows the frequency characteristics of the radiation directivity when the center frequency is set to "5, 6" and the frequencies are varied in the transmission and reception frequency bands. From this result, approximately 25 ° to 6
It can be seen that the gain is constant in the range of 0 °.

By changing the number of turns of the helical as described above, the beam of elevation angle can be changed, and as a result, it becomes possible to track the moving body even if the moving range of the moving body changes more widely.

[0033]

As described above in detail, according to the present invention, since the phase varying portion is provided at the central portion of the element of the helical antenna, the current distribution and directivity can be controlled. Further, since the number of turns of the helical in the helical antenna can be set variably, the beam of elevation angle can be changed by changing the number of turns.

Therefore, the helical antenna according to the present invention can be used as an antenna for a moving body that can tilt the elevation angle of the beam within the range of use, either fixedly installed or mounted on the moving body.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a variable directivity helical antenna device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration example of a phase variable unit in the same embodiment.

FIG. 3 is a diagram showing a current distribution in the example.

FIG. 4 is an impedance characteristic diagram in the example.

FIG. 5 is an impedance characteristic diagram in the example.

FIG. 6 is a diagram showing vertical directional characteristics in the same embodiment.

FIG. 7 is a diagram showing vertical directional characteristics in the same embodiment.

FIG. 8 is a diagram showing a gain characteristic in the example.

FIG. 9 is a structural diagram of a helical antenna according to a second embodiment of the present invention.

FIG. 10 is a perspective view showing the overall configuration of the same embodiment.

FIG. 11 is a configuration diagram showing details of an antenna unit in the embodiment.

FIG. 12 is a diagram showing radiation directivity in the example.

FIG. 13 is a diagram showing frequency characteristics of gain in the example.

FIG. 14 is a diagram showing frequency characteristics of radiation directivity in the example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical member 2 Antenna element 3 Phase variable part 11 1st antenna element 12 2nd antenna element 13 Varactor diode 15 Voltage variable circuit 21 Cylindrical member 22 Antenna element 23 Antenna base 24 Antenna part 25 External protection cylinder 27 Outer cylinder 28a, 28b, 30a, 30b Guide groove 29 Inner cylinder 31 Knob for adjusting number of turns 32 Antenna member 33 Cylinder for holding element 34 Element part 35a, 35b Protrusion for guide 36 Film-like insulating member 37a to 37c Element mounting member

Continuation of the front page (72) Inventor Gensada Sato 4-72 Miyagaya Tower, Omiya City, Saitama Antena Giken Co., Ltd.

Claims (2)

[Claims] 1. A variable directivity helical antenna, comprising: a helical antenna; and a phase variable section provided at a central portion of an element of the helical antenna, wherein directivity is variable by setting a phase in the phase variable section. apparatus. 2. A helical antenna element formed by winding a plurality of conductor wires in a cylindrical shape with an arbitrary diameter and at an equal pitch with an arbitrary pitch, and the number of turns N with a constant diameter of the antenna element.
And a variable directivity helical antenna device, wherein the directivity is variable by variably setting the number of turns N of the antenna element.