JP2001339228A - Helical antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a helical antenna which is made compact with ease and has a large flexibility in designing. SOLUTION: A main circuit board 3 is provided inside one axial end part of a cylindrical member 1 made of an insulator. The main circuit board is built on a cylindrical member along its axis. A low-noise amplifying circuit is mounted on the main circuit board. The low-noise amplifying circuit is connected to a conductor 2 wound helically around the cylindrical member. The main circuit board may be built on the cylindrical member while crossing its axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention receives digital radio broadcasts by receiving radio waves from artificial satellites (hereinafter also referred to as "satellite waves") or radio waves on the ground (hereinafter also referred to as "terrestrial waves"). And more particularly to an antenna used in a digital radio receiver.

[0002]

2. Description of the Related Art Recently, a digital radio receiver capable of receiving a radio wave (satellite wave) or a terrestrial wave from an artificial satellite so as to listen to a digital radio broadcast has been developed and is being put to practical use in the United States. This digital radio receiver is mounted on a mobile station such as an automobile and has a frequency of about 2.3G.
It is possible to listen to a radio broadcast by receiving a radio wave of Hz. That is, the digital radio receiver is a radio receiver that can listen to mobile broadcasts. still,
The terrestrial wave is obtained by temporarily receiving a satellite wave at an earth station and then slightly shifting the frequency.

In order to receive such a radio wave of a frequency of about 2.3 GHz, it is necessary to install an antenna outside the automobile. As such an antenna, various antennas can be considered, but a stick type is generally used instead of a flat type (flat type). Also, as is well known, an electromagnetic wave radiated in free space is a transverse wave having an electric field and a magnetic field oscillating in a plane perpendicular to the traveling direction of the wave, and the electric field and the magnetic field change in intensity in the plane. However, this is called polarization. Satellite waves are circularly polarized waves, whereas terrestrial waves are linearly polarized waves.

Hereinafter, an antenna for receiving a satellite wave will be mainly described. A helical antenna is known as one of the stick antennas. The helical antenna has a structure in which a conductor is wound in a helix (spiral) around a cylindrical or cylindrical tubular member, and can efficiently receive the above-mentioned circularly polarized waves. Therefore, the helical antenna is used exclusively for receiving satellite waves.

[0005] Satellite waves (circularly polarized waves) received by the helical antenna are combined in phase (adjusted) by shifting the phase by a phase shifter, and amplified by a low noise amplifier (LNA). , Sent to the receiver body.

Conventionally, a separate bottom case is attached to the lower end of a helical antenna, and an LNA is provided in the bottom case. That is, the LNA is provided separately from the cylindrical member of the helical antenna.

[0007]

However, the structure requires a bottom case, which hinders miniaturization of the antenna and limits the design.

Therefore, an object of the present invention is to provide a helical antenna which can be easily reduced in size and has a high degree of freedom in design.

[0009]

According to the present invention, there is provided a helical antenna having a tubular member (1) made of an insulator and a conductor (2) wound in a helix around the tubular member. A main circuit board (3) mounted inside one end of the cylindrical member in the axial direction; and a low noise amplifier circuit (5) mounted on the main circuit board and connected to the conductor. A helical antenna characterized by the above feature is obtained.

According to the present invention, in a helical antenna having a tubular member (1) made of an insulator and a conducting wire (2) wound in a helical shape around the tubular member, a shaft of the tubular member is provided. A main circuit board (3) mounted inside the one end in a direction parallel to the axial direction, and a low-noise amplifier circuit (5) mounted on the main circuit board and connected to the conductor. A helical antenna characterized by being provided is obtained.

Further, a phase shifter (6) supported by the cylindrical member and connected between the conductor and the low-noise amplifier circuit may be provided.

Furthermore, a phase shift circuit (8) mounted on the main circuit board and connected between the conductor and the low noise amplifier circuit may be provided.

Further, a sub-circuit board (9) mounted on the cylindrical member in parallel with the main circuit board, and connected between the conductor and the low-noise amplifier circuit mounted on the sub-circuit board. May be provided.

The cylindrical member may have a groove (4) on the inner surface of the one end, and the main circuit board may be inserted into the groove.

According to the present invention, in a helical antenna having a tubular member (11) made of an insulator and a conducting wire (12) wound in a helical shape around the tubular member, the shaft of the tubular member is provided. A main circuit board (13) mounted near the one end in the direction in a direction intersecting the axial direction, and a low-noise amplifier circuit (15) mounted on the main circuit board and connected to the conductor are provided. A helical antenna characterized by the above feature is obtained.

[0016] The main circuit board may extend perpendicular to the axial direction.

Further, a phase shifter (16) supported by the cylindrical member and connected between the conductor and the low-noise amplifier circuit may be provided.

Further, a sub-circuit board (18) mounted inside the tubular member in parallel with the main circuit board, and a sub-circuit board mounted on the sub-circuit board and between the conductor and the low noise amplifier circuit. A connected phase shift circuit (21) may be provided.

Further, the outer periphery may be wrapped around with a dielectric sheet (23).

Further, a dielectric rod (24) may be inserted and arranged inside the cylindrical member.

The cylindrical member may have a cut groove (14) on a side surface, and the main circuit board may be inserted into the cylindrical member through the cut groove.

The reference numerals in the parentheses are provided for easy understanding of the present invention, and are merely examples, and it is a matter of course that the present invention is not limited to these.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of the present invention will be described below in detail with reference to the drawings.

A helical antenna according to a first embodiment of the present invention will be described with reference to FIGS.
The illustrated helical antenna is a four-phase feeding helical antenna, and has a cylindrical member 1 made of plastic cylindrical insulator or the like having a diameter of about 20 mm and a length of about 120 mm, and is wound helically around the outer peripheral surface of the cylindrical member 1. And, for example, four conductive wires 2. The conductor 2 is a cylindrical member 1
At one end in the axial direction, that is, at a position slightly away from the lower end. The conductive wire 2 may be formed by printing a plurality of conductor patterns on an insulating sheet, that is, winding the insulating sheet with the conductor pattern around the tubular member 1.

Inside one end of the cylindrical member 1 in the axial direction,
The main circuit board 3 is mounted in a posture parallel to the axial direction. The main circuit board 3 is inserted from the lower end into a pair of grooves 4 formed to extend in the axial direction so as to face the inner surface of one end of the tubular member 1 in the radial direction. That is, the main circuit board 3 is vertically inserted into the cylindrical member 1 on the cylindrical axis. On the main circuit board 3, a low noise amplifier circuit 5 known in this type of technology is mounted.

At a relatively lower portion of the outer peripheral surface of the tubular member 1, there is provided a phase shifter 6 known in this type of technology. The phase shifter 6 is formed integrally along the outer peripheral surface of the tubular member 1. The phase shifter 6 is electrically connected to each of the plurality of conductors 2, and is collectively pulled out inside the cylindrical member 1 and is electrically connected to the low-noise amplifier circuit 5 of the main circuit board 3.

Thus, the low noise amplifier circuit 5 is connected to the conductor 2 via the phase shifter 6. An output cable 7 is also electrically connected to the low noise amplifier circuit 5.

The satellite wave (circularly polarized wave) received on the conductor 2 is
The phase is shifted by the phase shifter 6, the phases are matched (adjusted) and combined, amplified by the low noise amplifier 5, and sent to the receiver main body (not shown) through the output cable 7.

According to this helical antenna, since the low-noise amplifier circuit 5 and the phase shifter 6 are built in the inside of the tubular member, it is possible to easily reduce the size and increase the design freedom. Play.

A helical antenna according to a second embodiment of the present invention will be described with reference to FIGS.
Similar parts are denoted by the same reference numerals and description thereof is omitted.

In the illustrated helical antenna, the main circuit board 3 is enlarged upward, and a phase shift circuit 8 corresponding to the phase shifter 6 in FIG. The phase shift circuit 8 is electrically connected between the conductor 2 and the low noise amplifier circuit 5.

According to the helical antenna, since the low-noise amplifier circuit 5 and the phase shift circuit 8 are mounted on the main circuit board 3, there is an effect that cost can be reduced by reducing the number of parts and simplifying the structure. Play more.

A helical antenna according to a third embodiment of the present invention will be described with reference to FIGS.
Similar parts are denoted by the same reference numerals and description thereof is omitted.

In the illustrated helical antenna, a sub-circuit board 9 parallel to the main circuit board 3 is mounted on the tubular member 1. The sub-circuit board 9 also has a pair of grooves 10 formed on the inner surface at one end of the tubular member 1 so as to extend in the axial direction.
Is inserted from the lower end. On the sub-circuit board 9,
Phase shift circuit equivalent to phase shift circuit 8 in FIG. 3 (not shown)
Is provided. This phase shift circuit is electrically connected to the conductor 2 and also to the low noise amplifier circuit 5 of the main circuit board 3 via connection pins. That is, the phase shift circuit mounted on the sub-circuit board 9 is connected between the conductor 2 and the low-noise amplifier circuit 5.

According to this helical antenna, the main circuit board 3 on which the low-noise amplifier circuit is mounted and the sub-circuit board 9 on which the phase shift circuit is mounted are arranged parallel to each other, so that the axial dimension is made relatively small. The effect that can be performed is further exhibited.

A helical antenna according to a fourth embodiment of the present invention will be described with reference to FIG. The illustrated helical antenna is a four-phase feeding helical antenna, and includes a cylindrical member 11 made of a plastic cylindrical insulator having a diameter of about 20 mm and a length of about 120 mm.
A plurality of helical coils wound around the outer peripheral surface of one, for example,
And four conducting wires 12. The conductor 12 is a cylindrical member 1
At one end in the axial direction, that is, at a position slightly away from the lower end. The conductive wire 12 may be formed by printing a plurality of conductive patterns on an insulating sheet, that is, winding the insulating sheet with the conductive pattern around the tubular member 11.

In the vicinity of one end of the cylindrical member 11 in the axial direction, a disk-shaped main circuit board 13 is mounted in a posture intersecting with the axial direction, particularly, in a posture orthogonal to the axial direction. Main circuit board 13
Is inserted from a side surface into a cut groove 14 formed on a side surface near one end of the cylindrical member 11. That is, the main circuit board 13 has a structure in which the main circuit board 13 is laterally inserted into the tubular member 11 from the side. As shown in FIG. 8, a main circuit board 13 includes a low-noise amplifier circuit 15 known in this type of technology.
Is installed.

At a relatively lower portion of the outer peripheral surface of the cylindrical member 11,
It has a phase shifter 16 known in the art. The phase shifter 16 is provided on the cylindrical member 11 according to the film pattern.
Is formed integrally with the outer peripheral surface of the. The phase shifter 16 is electrically connected to each of the plurality of conductors 2, and is collectively pulled out to the inside of the cylindrical member 11 to be connected to the main circuit board 1.
3 low noise amplifier circuit 15.

Thus, the low-noise amplifier circuit 15 is provided with the phase shifter 16
Is connected to the conducting wire 12 through the wire. Low noise amplifier circuit 1
An output cable 17 is also electrically connected to 5.

Satellite wave (circularly polarized wave) received by the conductor 12
Are synthesized by matching (adjusting) the phase by shifting the phase by the phase shifter 16, and the low noise amplifier 1
5 and sent to the receiver main body (not shown) through the output cable 17.

According to the helical antenna, since the low-noise amplifier circuit 15 and the phase shifter 16 are assembled to the cylindrical member 11, the size can be easily reduced and the degree of freedom in design is increased. . In addition, since the main circuit board 13 is mounted on the tubular member 11 in a posture intersecting in the axial direction, the axial dimension can be reduced.

A helical antenna according to a fifth embodiment of the present invention will be described with reference to FIG. Similar parts are denoted by the same reference numerals and description thereof is omitted.

In the illustrated helical antenna, a sub-circuit board 18 is further mounted on the cylindrical member 11 in a posture parallel to the main circuit board 13, that is, in a posture orthogonal to the axial direction. Like the main circuit board 13, the sub-circuit board 8 also
Cut groove 19 formed on a side surface near one end of cylindrical member 11
Is inserted from the side.

As shown in FIG. 10, the sub-circuit board 18 is provided with a phase shift circuit 21 corresponding to the phase shifter 16 in FIG. The phase shift circuit 21 is electrically connected to the conductor 12 and is connected to the main circuit board 13 via connection pins 22.
Is also electrically connected to the low-noise amplifier circuit 15. That is, the phase shift circuit 21 mounted on the sub-circuit board 18 is connected between the conductor 12 and the low-noise amplifier circuit 15.

The entire outer periphery of the helical antenna shown in FIG. 9 may be wrapped around with a dielectric sheet 23 as shown in FIG. As the dielectric sheet 23, a film sheet having a high dielectric constant is suitable.

According to this structure, the effect of shortening the wavelength is obtained, so that the helical antenna can be made thinner and shorter.

The entire outer periphery of each helical antenna shown in FIGS. 1, 3, 5, and 7 may be wrapped around with a similar dielectric sheet, and the same effect can be obtained in that case.

Also, a dielectric rod 24 as shown in FIG. 12 may be coaxially inserted and arranged inside the cylindrical member 11 of the helical antenna shown in FIG. A ceramic rod is suitable as the dielectric rod 24. Note that the dielectric rod 24 is preferably as thick as possible.

According to this structure, the effect of shortening the wavelength is obtained, so that the helical antenna can be made thinner and shorter.

Similar dielectric rods may be inserted and arranged inside the cylindrical members 1 and 11 of each helical antenna shown in FIGS. 1, 3, 5 and 7, and in this case, the same applies. Effects can be obtained.

Furthermore, the entire outer periphery of the various helical antennas described above may be wrapped around with a dielectric sheet, and a dielectric rod may be inserted and arranged inside the cylindrical member.

In any of the embodiments, only one conductor may be used. In that case, a phase shifter or a phase shift circuit is naturally unnecessary.

[0053]

As described above, according to the present invention,
Since the main circuit board on which the low-noise amplifier circuit is mounted is built in the inside of the tubular member, it is possible to provide a helical antenna that can be easily reduced in size and has a high degree of freedom in design.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a helical antenna according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II of FIG.

FIG. 3 is a schematic front view of a helical antenna according to a second embodiment of the present invention.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3;

FIG. 5 is a schematic front view of a helical antenna according to a third embodiment of the present invention.

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 5;

FIG. 7 is a schematic front view of a helical antenna according to a fourth embodiment of the present invention.

FIG. 8 is a plan view of a main circuit board used for the helical antenna of FIG. 7;

FIG. 9 is a schematic front view of a helical antenna according to a fifth embodiment of the present invention.

FIG. 10 is a plan view of a sub-circuit board used for the helical antenna of FIG. 9;

FIG. 11 is a perspective view showing an example of a dielectric sheet surrounding the helical antenna of FIG. 9;

12 is a perspective view of a dielectric rod inserted and arranged inside the cylindrical member of the helical antenna of FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical member 2 Conductor 3 Main circuit board 4 Groove 5 Low noise amplification circuit 6 Phase shifter 7 Output cable 8 Phase shift circuit 9 Sub circuit board 10 Groove 11 Cylindrical member 12 Conductor 13 Main circuit board 14 Cut groove 15 Low noise Amplifier circuit 16 Phase shifter 17 Output cable 18 Sub-circuit board 19 Cut groove 21 Phase shift circuit 22 Connection pin 23 Dielectric sheet 24 Dielectric rod

Claims (13)

[Claims] 1. A helical antenna having a cylindrical member made of an insulator and a conductor wound in a helical shape around the cylindrical member, the helical antenna being assembled inside one end of the cylindrical member in the axial direction. And a low-noise amplifier circuit mounted on the main circuit board and connected to the conductor. 2. A helical antenna having a tubular member made of an insulator and a conductive wire wound in a helical shape around the tubular member, wherein the axial direction is set inside one axial end of the tubular member. A helical antenna, comprising: a main circuit board mounted in a posture parallel to the main circuit board; and a low noise amplifier circuit mounted on the main circuit board and connected to the conductor. 3. The helical antenna according to claim 2, further comprising a phase shifter supported by said cylindrical member and connected between said conductor and said low noise amplifier circuit. 4. The helical antenna according to claim 2, further comprising a phase shift circuit mounted on said main circuit board and connected between said conductor and said low noise amplifier circuit. 5. A sub-circuit board mounted on the tubular member in parallel with the main circuit board; and a sub-circuit board mounted on the sub-circuit board and connected between the conductor and the low noise amplifier circuit. The helical antenna according to claim 2, further comprising a phase shift circuit. 6. The helical antenna according to claim 2, wherein the cylindrical member has a groove on the inner surface of the one end, and the main circuit board is inserted into the groove. 7. A helical antenna having a tubular member made of an insulator and a conductive wire wound in a helix around the tubular member, wherein the helical antenna intersects the axial direction near one end of the tubular member in the axial direction. A main circuit board assembled in a posture
A helical antenna provided with a low-noise amplifier circuit mounted on the main circuit board and connected to the conductor. 8. The helical antenna according to claim 7, wherein the main circuit board extends perpendicular to the axial direction. 9. The helical antenna according to claim 7, further comprising a phase shifter supported by said tubular member and connected between said conductor and said low noise amplifier circuit. 10. A sub-circuit board mounted inside the tubular member in parallel with the main circuit board, and connected between the conductor and the low-noise amplifier circuit mounted on the sub-circuit board. 9. The helical antenna according to claim 7, further comprising a phase shift circuit provided. 11. The helical antenna according to claim 7, wherein the outer periphery is further wrapped around a dielectric sheet. 12. The helical antenna according to claim 7, wherein a dielectric rod is further inserted inside said cylindrical member. 13. The cylindrical member has a cut groove on a side surface,
The helical antenna according to any one of claims 7 to 12, wherein the main circuit board is inserted into the tubular member through the cut groove.