JP2003318616A - Antenna tuner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna tuner which allows the resonance frequency of an antenna circuit to be adjusted by a simple manual operation. <P>SOLUTION: A fixed assembly 1 is composed of a circular flange 11, a hollow circular tube 10 with windings of a loading coil 20, and a fixing block 30 with a connector 40 attached thereto. The coil 20 is a conductor wire, wound along a spiral groove formed into the outer side of the hollow tube 10 and one end thereof is connected to the connector, after passing through the tube 10. A movable assembly 2 is a coaxial connection series of an antenna 50, an antenna coupling tube 60, a bearing 70 and an insulator operating tube 80. The bearing 70 incorporates with a mechanism for pressing steel balls 74 inwardly by leaf springs 76 and surrounds the coil 20, to compositely form a sliding pair and a screw pair. The operating tube 80 is shifted in the axial direction to make rough adjustment and rotated to make fine adjustment. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna tuning device for adjusting the electric length of an antenna to the wavelength of transmitted / received radio waves, and more particularly to a device capable of mechanically adjusting the inductance of a loading coil.

[0002]

2. Description of the Related Art Conventionally, a loading coil is connected in series to an antenna element in order to adjust the resonance frequency of an antenna circuit (in order to match the electric length of the antenna with the wavelength of transmitted and received radio waves). ing. That is, as shown in FIG. 5, the length of the antenna 51: a
Is shorter than (λ / 4) [where λ is the wavelength of the transmitted / received radio wave], the loading coil 90 is inserted between the antenna 51 and the antenna terminal of the wireless communication device 52.

In this case, the resonance frequency of the antenna circuit is
When the loading coil 90 is not inserted,
As Fr of (1) and the following formula (2) when inserted.
Given as Fr '. However, in each formula, Lo and Co are antenna constants of the antenna 51, and L is the inductance of the loading coil 90.

[Equation 1]

[Equation 2] As is clear from these equations, the insertion of the loading coil 90 lowers the resonance frequency of the antenna circuit.

By the way, in a simple fixed station wireless communication device or a mobile or field operated wireless communication device, a telescopic whip antenna is often used, but generally, these wireless communication devices have many bands. Covers. For example, the bands allowed for amateur radio stations are the 1.9 MHz band to the 249 GHz band,
12 from the 1.9 MHz band even in commercially available wireless communication devices
Many cover up to the 00MHz band.

Therefore, it is necessary to adjust the resonance frequency of the antenna circuit according to the selected band. In principle, the resonance frequency can be adjusted by adjusting the length of the whip antenna or the inductance of the loading coil. . However, with the former adjustment method, it is difficult to manually adjust to an accurate length, and it is troublesome to expand and contract each time the band is switched, so the latter adjustment method is generally adopted. To be done. That is, a method is adopted in which the maximum length when the antenna is extended is set so that the resonance frequency of the antenna circuit corresponds to the band with the lowest frequency, and the inductance of the loading coil is electrically controlled and adjusted. ing.

Specifically, for example, a technique in which an LC circuit is connected to an antenna circuit via a manual changeover switch and the electric length of the antenna is changed according to the reception frequency using the changeover switch (Japanese Patent Laid-Open No. 4-334201). ) Or a capacitor whose capacitance changes according to the control voltage and a coil whose inductance changes depending on the control voltage, and the resonance frequency of the antenna circuit is changed by changing the control voltage depending on the frequency band (JP-A-4-213907).
Etc. are proposed and disclosed.

[0007]

By the way, in the above-mentioned inductance adjusting method of the antenna circuit, a predetermined inductance is set by a switch operation or a band selecting operation. However, the resonance frequency of the antenna circuit is set to a feeder (feed line). ), The environment such as the installation location of the antenna, the state of radio wave propagation during communication, and the like are subtly different, and the set inductance does not always give the best transmission power efficiency and reception sensitivity. Since the problem is related to the antenna circuit, it cannot be corrected on the side of the wireless communication device to obtain the best state.

Therefore, the present invention provides an antenna tuning device capable of performing a coarse adjustment and a fine adjustment by mechanically changing the inductance of the loading coil, and the resonance frequency of the antenna circuit can be accurately adjusted to a selected band by a simple manual operation. It was created with the aim of setting wireless communication with the best transmission power efficiency and reception sensitivity.

[0009]

SUMMARY OF THE INVENTION The present invention is a combination mechanism of a fixed side assembly and a movable side assembly, wherein the fixed side assembly is an insulator having an outward circular flange at one end thereof. A spiral groove having a constant pitch is formed on the outer peripheral surface of a long hollow cylinder, and a conducting wire is fitted in the groove to form a loading coil, and a feeding coil is connected to the opposite end of the hollow cylinder. A fixing block provided with a connector is attached, one end of the loading coil on the side of the circular flange is fixed to the hollow cylinder, and the other end of the fixing coil is passed through a hole bored in the hollow cylinder through the inside of the cylinder. The movable side assembly is a hollow cylinder of a conductor that is loosely fitted to the loading coil. A groove is formed in the outer peripheral surface in the circumferential direction, and a plurality of spherical bodies that are conductors are arranged at circumferential positions where the central angles with respect to the cylinder axis in the range where the groove is formed are uniform, and A bearing portion fitted in each hole formed at a position in the axial direction in contact with each adjacent winding of the loading coil and biasing each of the spherical bodies inward by a leaf spring attached to the groove, and the fixed side. A hollow cylinder of a conductor that fits and slides on a circular flange of an assembly, one end of which is fitted and fixed to the bearing portion, and the other end of which is an antenna coupling cylinder portion coaxially coupling an antenna, The antenna tuning device is characterized in that it is a hollow cylinder of an insulator, and has one end composed of an operating cylinder part that is externally fitted and fixed to the bearing part or the antenna connecting cylinder part.

According to the present invention, both assemblies are assembled with the bearing portion of the movable side assembly fitted onto the loading coil of the fixed side assembly. And
A screw pair and a sliding pair are combined between the bearing portion and the loading coil. First, the loading coil is fitted in the groove of the hollow cylinder of the fixed side assembly and wound in a spiral shape, and each sphere of the bearing portion is in contact with each adjacent winding in a state of being fitted in the valley of the loading coil. . Therefore, each sphere becomes a partial female screw with respect to the loading coil that is a male screw, and the loading coil and the bearing portion form a screwing relationship. Also, since each sphere is only biased inward by the leaf spring in the hole of the bearing, when an external force is applied to the bearing in the axial direction, it is pushed outward by the crest of the loading coil. Over the mountain of the loading coil while bending the leaf spring.
That is, the bearing can be moved in the axial direction with the winding pitch of the loading coil as a unit step.
By the way, the antenna circuit is composed of a series circuit of an antenna which is a conductor, an antenna connecting cylinder portion, a bearing portion and a loading coil. One end of the loading coil is connected to the connector of the fixing block. The inductance of is determined by the contact position of the sphere of the bearing with the winding. Therefore, when the movable side assembly is moved in the axial direction by the operation tube portion, the inductance of the loading coil can be roughly adjusted by the sliding pair, and the sphere and the loading coil can be stopped by the engaging relationship in the axial direction. You can Further, when the operating cylinder of the movable side assembly is rotated at the position after the rough adjustment, the movable side assembly can be finely moved in the axial direction based on the screw pair, and the inductance of the loading coil can be finely adjusted. it can. Since the operating cylinder is an insulator, it does not cause an electric shock during manual operation and does not affect the inductance during the adjustment process. In addition, since a rotating pair and a sliding pair are formed between the circular flange of the fixed side assembly and the antenna connecting cylinder portion, during the above-mentioned movement / rotation, the axis of the movable side assembly relative to the fixed side assembly is Inclination can be prevented and a guidance function can be obtained.

In the present invention, the number of spheres used for the bearing portion of the movable side assembly is plural, and each sphere is fitted into the hole formed under the predetermined position condition according to the number, but four spheres are provided. In the case of using, each hole is formed at a position in the circumferential direction where the central angle with respect to the cylinder axis is 90 °, and in the axial direction by (1/4) pitch of the winding of the loading coil according to the circumferential order. The positions are set to be different from each other, and one pair is set for each pair of two spherical bodies that are fitted in the holes adjacent to each other with a shift of (1/4) pitch in the axial direction.
It is desirable to apply a single leaf spring. And, the leaf spring applied in that case, a fixed plate portion screwed to the center between the formation positions of the paired holes, and continuously formed at a predetermined angle on both sides of the fixed plate portion, It is assumed that the fixed plate portion is composed of both side plate portions that press inwardly each sphere fitted in the pair of holes in a screwed state. With this configuration, it is possible to realize a screw pair that prevents shaft deviation with a minimum number of parts, and to compactly configure the biasing mechanism for the steel ball of the bearing portion.

By the way, in the present invention, the resonance frequency of the antenna circuit is roughly adjusted by moving the movable side assembly in the axial direction, but generally, the rough adjustment is generally performed according to the band used on the wireless communication device side. It only needs to correspond, and relatively rough operation is sufficient. However, if there is no standard, it is necessary to adjust the reception sensitivity and the like of the wireless communication device one by one. On the other hand, the resonance frequency of the antenna circuit can be obtained in advance by measuring the reception sensitivity and the like while experimentally changing the relative position of the movable side assembly with respect to the fixed side assembly. Therefore, in the relative position state of the fixed side assembly and the movable side assembly when a representative resonance frequency is experimentally obtained, the resonance frequency of the fixed side assembly corresponding to the position of the end portion of the operating cylinder is adjusted. If it is written on the surface of the hollow cylinder, the rough adjustment operation becomes extremely easy.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
It will be described in detail with reference to FIG. First, FIG. 1A is an axial sectional view of the antenna tuning device. In the figure, 10 is a hollow cylinder provided with an outward circular flange portion 11 at one end, 20 is a loading coil wound around the hollow cylinder 10, and 30 is a fixing coil to which the other end of the hollow cylinder 10 is fitted. Blocks 40 are connectors attached to the fixing block 30, and the fixed side assembly 1 is constituted by them.

Here, the hollow cylinder 10 is made of an insulator (for example, fiber reinforced plastic, bakelite, etc.) having excellent high frequency characteristics and high mechanical strength, and is provided on the outer peripheral surface corresponding to the winding section of the loading coil 20. A spiral groove is formed at a constant pitch: p, and the loading coil 2 is mounted by fitting the conductor wire along the groove.
0 is configured. Loading coil 2
The upper end of 0 is inserted and fixed in the hole 12 formed in the hollow cylinder 10, but the lower end penetrates the hole 13 formed in the hollow cylinder 10 to enter the cylinder and is fixed through the cylinder. Is led to the block 30. The fixing block 30 is made of a conductor such as aluminum and has a hollow inside, but the central conductor of the connector 40 attached to the side surface projects into the hollow portion and is guided to the central conductor from the loading coil 20. Connected conductors are connected.

On the other hand, in FIG. 1A, 50 is a whip antenna, 60 is an antenna connecting cylinder, 70 is a bearing, and 80 is an operating cylinder, and these parts are coaxially connected and movable. The side assembly 2 is constructed. Here, the whip antenna 50 is naturally a conductor, and the antenna connecting cylinder portion 60 and the bearing portion 70 are also made of a conductor such as aluminum, but the operation cylinder portion 80 is made of an insulator such as an epoxy resin.

The connecting mechanism between the whip antenna 50 and the antenna connecting cylinder portion 60 is constructed such that a sealing boss 61 made of stainless steel or the like is fitted into the upper open end of the antenna connecting cylinder portion 60 and screwed from the outer peripheral surface side. (Not shown), and a male screw projecting from the lower end of the whip antenna 50 is fastened to a female screw hole formed in the center of the sealing boss 61. The connecting mechanism of the antenna connecting tubular portion 60 and the operating tubular portion 80 with respect to the bearing portion 70 includes a bearing portion 70.
Is formed with a small diameter corresponding to the thickness of the antenna connecting tube portion 60, and the lower end portion of the antenna connecting tube portion 60 is externally fitted to the upper section, and the bearing portion 70 and the antenna connecting tube are The upper end portion of the operating cylinder portion 80 is externally fitted and fixed to the outer peripheral surface of the portion 60. (Since their fitting relationship can be understood more concretely from FIGS. 1 (C) and 1 (D), reference should be made to their sectional views.)
Although not shown, the fixing means includes a hole formed in the fitting section of the operating cylinder 80 and the antenna connecting cylinder 60 and a female screw hole formed in the bearing 70. It is adapted and screwed from the outside.

As shown in FIG. 1 (A), the bearing portion 70 of the movable side assembly 2 is adapted to be fitted onto the winding section of the loading coil 20 of the fixed side assembly 1. And loading coil 2
The relationship between the screw pair and the slip pair, which are configured in a complex manner with 0, is the main point of this embodiment, and the mechanism thereof will be specifically described below.

First, in a state in which the movable side assembly 2 is combined with the fixed side assembly 1, as shown in FIG. 1 (A), a cross-sectional view of a portion of the movable side assembly 2 where the bearing portion 70 is located (a cross section taken along arrow XX). ), The configuration is as shown in FIG. In addition, Y in FIG.
The sectional view taken along the line 1-Y1 is shown in FIG. 1C, and the sectional view taken along the line Y2-Y2 is shown in FIG. 1D.

As is apparent from FIGS. 1B and 1C, the upper portion of the bearing portion 70 is a sleeve having a small diameter, and the lower end portion of the antenna connecting tubular portion 60 is provided on the outer periphery thereof. It is fitted on. Further, a groove 71 is formed in the lower section of the bearing 70 in the circumferential direction, and the annular wall 72 corresponding to the bottom of the groove 71 has four holes 73 under predetermined position conditions. Has been formed. That is, the four holes 73 are formed at positions satisfying the following two conditions. The position in the circumferential direction at which the central angle of the bearing portion 70 with respect to the cylinder axis is 90 °. The winding pitch of the loading coil 20 should be shifted in the axial direction by ¼ of p according to the circumferential order.

A steel ball 74 is fitted into each of the holes 73, and the diameter of the steel ball 74 is larger than the winding pitch: p of the loading coil 20 and the thickness of the annular wall portion 72. It is larger than the thickness, as shown in Figure 1.
As shown in (D), the conductors are in contact with the adjacent conductors while being pressed against the loading coil 20. Therefore, the diameter of each hole 73 is set to be slightly larger than the diameter of the steel ball 74, so that the steel ball 74 can move in the hole 73.

The above-mentioned four steel balls 74, two of each of which are attached to the annular wall portion 72 with screws 75, are the leaf springs 7.
While being biased inward by 6, the loading coil 20
It is pressed to the side. That is, one plate spring 76 corresponds to a pair of steel balls 74, and each plate spring 76 has a fixed angle between the fixed plate portion 77 and its both sides fixed by screws (135 ° in a natural state). The side plate portion 78 is formed continuously with the fixed plate portion 77, and the fixing plate portion 77 is slightly bent to urge the pair of steel balls 76 inward. In addition, steel ball 74
Is naturally a conductor, and a conductor material such as a phosphor bronze plate is applied to the leaf spring 76.

The mechanism formed in the concave groove 71 of the bearing portion 70 can be easily understood with reference to FIG. 2, which is a schematic view of the concave groove 71 developed in plan. As shown in the figure, 4
The individual holes 73 are arranged under the above conditions and
Female screw hole 79 into which a screw 75 is screwed in the center of each pair of holes 73
Is formed, and a leaf spring 76 for pressing the steel ball 74 fitted in each pair of holes 73 inward is formed with a female screw hole 79.
It is fixed in the position. In addition, in this embodiment, the width of each leaf spring 76 is considerably smaller than the width of the concave groove 71, but the width of each leaf spring 76 may be set so as to fit into the concave groove 71 with a slight clearance. In that case, each leaf spring 76 can be prevented from rotating around the screw 75.

The antenna tuning device configured as described above is provided with the fixing block 3 of the fixed side assembly 1.
0 is fixed at an appropriate position, and the connector 40 is connected to an antenna connection connector on the radio communication device side by a coaxial cable for use. Then, when the used band is selected in the wireless communication device, the antenna tuning device is adjusted to the resonance frequency corresponding to the band.

In this case, first, the operating tubular portion 80 of the movable side assembly 2 is grasped and moved in the axial direction to roughly adjust the resonance frequency to the above-mentioned resonance frequency. That is, since each steel ball 74 of the bearing portion 70 is only elastically pressed against the loading coil 20 by the leaf spring 76, when a force in the axial direction acts on the movable side assembly 2, the leaf spring is pressed. 76 bends so that the steel balls 74 successively pass over the side windings, and the movable side assembly 2 moves in the axial direction with a relatively small operating force. Further, at the time of its movement, the circular flange portion 11 attached to the hollow cylinder 10 on the fixed side assembly 1 side slides in the antenna connecting tube portion 60 on the movable side assembly 2 side to perform a guiding function. At the same time, it plays a role of preventing the shaft of the movable side assembly 2 from inclining.

When the operation on the movable side assembly 2 is stopped, the movable side assembly 2 is locked to the fixed side assembly 1 in that state. Because the bearing 7
At 0, the forming position condition of the hole 73 into which each steel ball 74 is fitted is based on the above and
4 are pressed inward in a state of being respectively located in the valleys of the adjacent windings of the loading coil 20, and the movable side assembly 2 is attached to the fixed side assembly 1 in the axial direction.
This is because they are engaged at the points.

By the way, the antenna circuit in this antenna tuning device is an equivalent circuit as shown in FIG. That is, the antenna circuit is the whip antenna 50.
An antenna connecting cylinder portion 60 connected to the whip antenna 50 via a sealing boss 61, a bearing portion 70,
The leaf coil 76 and the inductance Lv below the contact point of the steel ball 74 of the loading coil 20 connected to the bearing 70 via the steel ball 74.
In other words, the steel ball 74 in the loading coil 20.
Only the portion below the contact point with will function as an effective inductance Lv. The inductance Lv gives the inductance L of the loading coil in the above equation (2), and when the movable side assembly 2 is moved in the axial direction, the resonance frequency Fr 'of the antenna circuit can be adjusted.

However, in principle, even if this is the case, if there is no standard for the operator, the resonance frequency Fr of the antenna circuit is moved to which position the movable side assembly 2 is moved. It is unclear whether or not 'applies to the band used by the wireless communication device, and it is necessary to operate the movable side assembly 2 while referring to the reception sensitivity of the wireless communication device and the like. Therefore, in this embodiment, as shown in FIG. 4, the resonance frequency Fr ′ of the antenna circuit based on the relative positional relationship of the movable side assembly 2 to the fixed side assembly 1 is set at the position of the lower end 81 of the operating cylinder portion 80. The center frequency of each used band is indicated on the surface of the hollow cylinder 10 of the fixed side assembly 1 corresponding to the position. Then, the notation position of the resonance frequency for each band is to perform a trial communication in which the center frequency of each band is set in advance by a wireless communication device using this antenna tuning device, and at that time, the best receiving sensitivity is obtained. It should be the position at the time of being hit. Further, it goes without saying that the result obtained by one antenna tuning device can be applied to the device having the same specifications as it is.

Therefore, when the band to be used for the wireless communication device is set, the operator has the hollow cylinder 10 at the lower end of the operating cylinder 80.
It suffices to move the movable side assembly 2 so as to be at the position where the corresponding frequency is indicated, and coarse adjustment can be performed extremely easily and quickly. Incidentally, the notation position of each center frequency changes depending on the length of the whip antenna 50, but in general, it may be based on a state where the whip antenna 50 is extended to the longest or a state where the whip antenna 50 is set to a half length. . Further, as a notation method, a method of marking a frequency on the hollow cylinder 10 and filling it with a coating material, a method of sticking a seal on which a frequency is printed, or the like can be adopted.

By the way, the above-mentioned operation merely makes a rough adjustment to correspond to the band used on the radio communication device side. Because the notation of the resonance frequency for the hollow cylinder 10 is merely the center frequency of the used band,
Further, the movable side assembly 2 can be moved only in the movement step of the pitch: p based on the kinematic pair condition of the bearing portion 70 and the loading coil 20, and further, an error occurs because it is a manual operation in the axial direction. Because there are many.

Another feature of this embodiment is that fine adjustment can be performed by rotating the movable side assembly 2 after the rough adjustment. As described above, the four holes 73 formed in the bearing portion 70 are arranged under the positional conditions (the above conditions) corresponding to the loading coil 20, and are fitted into the respective holes 73. When the movable side assembly 2 is rotated based on the fact that a screw pair relationship is established between the steel ball 74 and the loading coil 20, the movable side assembly 2 is continuously separated by a minute distance according to the rotation angle. Can be moved automatically.
More specifically, the minimum movement step of the movable side assembly 2 with respect to the fixed side assembly 1 in the rough adjustment was the winding pitch of the loading coil 20: p, but with this fine adjustment, the movement amount per rotation is The pitch:
This corresponds to p, and a minute movement of (p / 360) can be continuously realized at a rotation angle of 1 °.

Therefore, the resonance frequency Fr 'of the antenna circuit can be finely adjusted by continuously finely changing the inductance Lv that effectively functions in the loading coil 20. As a result, the resonance frequency Fr ′ of the antenna circuit can be made to accurately correspond to the frequency used within the band selected on the wireless communication device side, and communication is always executed with the optimum transmission power efficiency and reception sensitivity set. be able to. Further, since the fine adjustment in this case is a rotating operation on the operating cylinder portion 80 after the rough adjustment is performed in advance, it can be easily performed while listening to the reception voice of the wireless communication device.

[0032]

The antenna tuning device of the present invention is
By having the above structure, the following effects are produced. According to the invention of claim 1, the connecting portion between the movable side assembly having the antenna attached thereto and the loading coil of the fixed side assembly is constituted by a combined mechanism (bearing portion) of a sliding pair and a screw pair utilizing the winding of the loading coil. Allows the resonance frequency of the antenna circuit to be adjusted accurately with a simple operation. The invention of claim 2 relates to claim 1
Reasonably realizing the bearing portion of the invention with a small number of parts. According to the third aspect of the invention, a typical resonance frequency of the antenna circuit is written on the surface of the hollow cylinder of the fixed side assembly, and the movable side assembly is moved by using this as a guide to roughly adjust to the resonance frequency. The operation is easy.

[Brief description of drawings]

FIG. 1 is an axial sectional view (A) of an antenna tuning device according to an embodiment of the present invention, and a transverse sectional view (B) of a bearing portion;
A cross-sectional view (C) taken along the line Y1-Y1 in the cross-sectional view (B),
FIG. 16 is a sectional view (D) taken along the line Y2-Y2 in the lateral sectional view (B).

FIG. 2 is a schematic view in which a concave groove portion of a bearing portion is developed two-dimensionally.

FIG. 3 is an equivalent circuit diagram of the antenna tuning circuit according to the embodiment.

FIG. 4 is a front view showing a hollow cylinder portion of a fixed side assembly in which a typical resonance frequency of an antenna circuit is shown.

FIG. 5 is an electric circuit diagram when a loading coil is inserted between the antenna and the wireless communication device.

[Explanation of symbols]

1 ... Fixed side assembly, 2 ... Movable side assembly, 1
0 ... Hollow cylinder, 11 ... Circular flange part, 12, 13 ...
Hole, 20 ... Loading coil, 30 ... Fixing block, 40 ... Connector, 50 ... Whip antenna, 60 ...
Antenna connection cylinder part, 61 ... Sealing boss, 70 ... Bearing part,
71 ... Recessed groove, 72 ... Annular wall portion, 73 ... Hole, 74 ... Steel ball,
75 ... Screw, 76 ... Leaf spring, 77 ... Fixed plate part, 78 ... Side plate part, 79 ... Female screw hole, 80 ... Operation cylinder part, 81 ... Lower end of operation cylinder part, 90 ... Loading coil, a ... Antenna , L, Lv ... Inductance, p ... Loading coil winding pitch, λ ... Wavelength of transmitted / received radio wave.

Claims (3)

[Claims] 1. A combination mechanism of a fixed side assembly and a movable side assembly, wherein the fixed side assembly is provided on an outer peripheral surface of a long hollow cylinder of an insulator having an outward circular flange at one end thereof. A fixing block in which a spiral groove having a constant pitch is formed, a conductive wire is fitted in the groove to form a loading coil, and a connector for connecting a power supply line is attached to the opposite end of the hollow cylinder is provided. One end of the loading coil on the side of the circular flange is fixed to the hollow cylinder, and the other end is connected from the hole formed in the hollow cylinder to the central conductor of the connector for connection of the fixing block through the inside of the cylinder. On the other hand, the movable side assembly is a hollow conductor cylinder that is loosely fitted to the loading coil, and has a concave groove in the outer peripheral surface in the circumferential direction. Is formed, and a plurality of spherical bodies that are conductors are in contact with each adjacent winding of the loading coil at circumferential positions where the central angles with respect to the cylinder axis in the range where the groove is formed are uniform. It is fitted into each hole formed in the axial position, and each spherical body is urged inward by the leaf spring attached to the groove and the outer ring is slidably fitted on the circular flange of the fixed side assembly. A hollow cylinder of a moving conductor, one end of which is externally fitted / fixed to the bearing portion, and the other end of which is an antenna coupling cylinder part in which an antenna is coaxially coupled, and a hollow cylinder of an insulator. The antenna tuning device is characterized by comprising: an operating cylinder part that is fitted and fixed onto the bearing part or the antenna connecting cylinder part. 2. The four spherical bodies are used for the bearing portion of the movable side assembly, and the holes for fitting these spherical bodies are provided.
At the position in the circumferential direction where the central angle with respect to the cylinder axis is 90 °, and in accordance with the circumferential direction, the winding of the loading coil (1
/ 4) It is formed at a position shifted in the axial direction by a pitch, and for every two pairs with respect to two pairs of spheres that are fitted in adjacent holes with a (1/4) pitch offset in the axial direction. A single leaf spring is applied, and the leaf spring is fixed to a fixed plate portion screwed in the center between the formation positions of the paired holes, and continuously on both sides of the fixed plate portion at a predetermined angle. The antenna tuning device according to claim 1, wherein the antenna tuning device comprises a pair of side plate portions configured to press the respective spheres fitted into the pair of holes inward with the fixed plate portion screwed. 3. A typical resonance frequency of an antenna circuit, which is determined by the relative position of the movable side assembly with respect to the fixed side assembly, corresponds to the position of the end of the operating tube portion in the relative position state. Claim 1 or Claim 2 written on the surface of the hollow cylinder of the assembly.
Antenna tuning device described in.