JPH11214914A - Antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna which makes an antenna element operate at a maximum power point. SOLUTION: A matching line 3 has about λ/2 length when a use frequency wavelength is λ has one end part 31 connected to an antenna element 2, has the other end 33 opened and sets up a feeding point 32 at the position of about λ/8 from the part 31. Alternatively, the line 3 has about λ/8 length, has the part 31 connected to the element 2, has the other end short-circuited and sets up the point 32 at the position of about λ/8 from the part 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device.

[0002]

2. Description of the Related Art Conventionally, various types of antennas are used in communication equipment used for mobile communication and communication systems such as local area networks. Examples include monopole whip antennas, air-core helical antennas, composite antennas consisting of a combination of monopoles and air-core helical antennas, modified air-core helical antennas, helical antennas wound on dielectric rods, and coaxial wires used to feed monopole antennas. What was, loop antenna, reverse F
An antenna, a patch antenna (microstrip antenna), a chip antenna, and the like can be given. Japanese Patent Laid-Open Publication No. Hei 6
318810, JP-A-7-122917,
JP-A-7-288412, JP-A-8-33082
9 and JP-A-9-51221.

In this type of antenna device, a large current flows through the antenna by utilizing the resonance phenomenon. However, it is important to reduce the size and weight of mobile communication devices, and monopole antennas that do not provide sufficient grounding and vertical mode helical antennas are mainly used to meet the demand. Used. For this reason, even if the configuration is such that the resonance phenomenon of the antenna is used, in practice, the resonance phenomenon cannot be sufficiently used, and the antenna cannot be operated at the maximum power point.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an antenna device capable of operating an antenna element at a maximum power point.

Another object of the present invention is to provide an antenna device which is less susceptible to external radio waves.

[0006]

In order to solve the above problems, the present invention discloses two different types of antenna devices. An antenna device according to a first aspect includes an antenna element, a matching line, and a feeding point. The matching line has a length of λ / 2 with respect to a used frequency wavelength λ, one end is connected to the antenna element, and the other end is open. The matching line has a feeding point set at about λ / 8 from the one end.

Since the matching line of the present invention has a total length of λ / 2 with respect to the operating frequency wavelength λ, the matching line resonates with a standing wave of λ / 2. In this case, the current distribution characteristic on the matching line is
At one end of the matching line connected to the antenna element and at the other end which is an open end, the current value becomes substantially zero, and the sinusoidal distribution characteristic becomes maximum at the center of the matching line. The voltage distribution characteristic is such that the voltage value becomes maximum (opposite phase with each other) at one end of the matching line connected to the antenna element and the other end which is an open end, and the voltage value is almost at the center of the matching line. It shows a sinusoidal distribution characteristic that becomes zero. Due to the above-described current distribution characteristics and voltage distribution characteristics, at the position of λ / 8 from the connection between the antenna element and the matching line, the voltage distribution and the current distribution have the same phase, and the power given by the product of the voltage and the current Is maximum on the matching line.

As described above, at the position of λ / 8 from the connection between the antenna element and the matching line, the voltage distribution and the current distribution are only in the same phase in the matching line, and the product of both becomes maximum. If a power supply point is provided for the connection part for transmission and reception, transmission and reception can be performed with maximum power without phase shift.

Further, since the matching line is a characteristic impedance line, it becomes a stable matching line, and the influence of external radio waves due to interference and radiation from other lines is eliminated.

[0010] Another antenna device according to the present invention includes:
Includes an antenna element, a matching line, and a feed point. The matching line has a length of λ / 4 with respect to a used frequency wavelength λ, one end is connected to the antenna element, and the other end is short-circuited. The feed point is set at a position of about λ / 8 from the one end of the matching line.

The matching line of the present invention resonates with a standing wave of λ / 4 since its total length is λ / 4 with respect to the operating frequency wavelength λ. In this case, the current distribution characteristic on the matching line shows a half-sine-wave distribution characteristic in which the current value becomes substantially zero at one end of the matching line connected to the antenna element and the current value becomes maximum at the short-circuited end. The voltage distribution characteristic shows a half-sinusoidal distribution characteristic which becomes maximum at one end of the matching line connected to the antenna element and becomes almost zero at the other end which is a short-circuited end. Due to the above-described current distribution characteristics and voltage distribution characteristics, the voltage distribution and the current distribution have the same phase at the position of λ / 8 from the connection between the antenna element and the matching line, and are given by the product of the voltage and the current. Power is maximized on the matching line.

As described above, when the voltage distribution and the current distribution are λ / 8 from the connection between the antenna element and the matching line,
Since the phase becomes the same and the product of the two becomes maximum, if a feed point is provided at this position to make a connection for transmission and reception, transmission and reception can be performed with maximum power without phase shift. Become.

Further, since the matching line is a characteristic impedance line, it becomes a stable matching line, and the influence of external radio waves due to interference and radiation from other lines is eliminated.

Other objects, configurations and advantages of the present invention will be described in more detail with reference to the accompanying drawings. The drawings are merely examples.

[0015]

FIG. 1 is a plan view of an antenna device according to the present invention, and FIG. 2 is a sectional view taken along line 2-2 of FIG. As shown, the antenna device according to the present invention includes an antenna element 2 and a matching line 3.

The antenna element 2 is housed in the housing 1. The antenna element 2 is, for example, helical, zigzag,
Various shapes such as a rod shape or a combination thereof can be adopted. One end of the antenna element 2 is guided to the outside of the housing 1, and is connected to a connection portion 31 which is one end of the matching line 3.

The matching line 3 has a total length L of λ / 2 with respect to the operating frequency wavelength λ (electrical wavelength), and has a feed point 32 at a position λ / 8 from the connection portion 31.
Is connected to a power supply path 34. The other end of the matching line 3 is an open end 33. 1.9GHz for PHS etc.
When the antenna is used as a PHS antenna device, the position of the feeding point 32 given by λ / 8 can be calculated from the frequency of 1.9 GHz.

In the embodiment, the matching line 3 includes a dielectric substrate 35, a metal strip line 36, and a ground conductor 371.
And The metal strip line 36 and the ground conductor 371 face each other with the dielectric substrate 35 interposed therebetween. More specifically, the metal strip line 36 and the ground conductor 37
Numerals 1 are provided on the front surface and the back surface of the plate-like dielectric substrate 35, respectively, and have a structure in which the dielectric substrate 35 between the both 36 and 371 is used as a dielectric layer. In the embodiment, the metal strip line 3 is also provided on the surface of the dielectric substrate 35.
6, a ground conductor 372 is provided.

The dielectric substrate 35 may be made of any of an organic dielectric and an inorganic dielectric. Specific examples of the organic dielectric include an epoxy resin and a tetrafluoroethylene resin. A specific example of the inorganic dielectric is a ceramic dielectric. The metal strip line 36 is formed on the dielectric substrate 35 using a material having good conductivity such as copper, nickel, silver, or gold, and is set to a specified line width to be a characteristic impedance line. The ground conductors 371 and 372 can be made of the same material as the metal strip line 36.

FIG. 3 is a diagram showing the operation principle of the antenna device of the present invention in use. In use, the communication device 4 is connected to a power supply path 34 connected to a power supply point 32. As described above, the entire length L of the matching line 3 is set to λ / 2 with respect to the operating frequency wavelength (electrical wavelength) λ, so that a resonance standing wave of λ / 2 exists on the matching line 3. . In this case, the current distribution characteristic I on the matching line 3 is such that the current value is substantially zero at one end of the matching line 3 which is the connection 31 with the antenna element 2 and at the other end which is the open end 33. And the sinusoidal distribution characteristic which becomes maximum at the center C1 of the matching line 3. FIG. The voltage distribution characteristic V becomes maximum (opposite phases) at one end of the matching line 3 which is the connection 31 with the antenna element 2 and the other end which is the open end 33, and becomes the center of the matching line 3. It shows a sinusoidal distribution characteristic that becomes almost zero at C1. Due to the current distribution characteristics I and the voltage distribution characteristics V described above, at the position of λ / 8 from the connection portion 31 between the antenna element 2 and the matching line 3, the voltage and the current have the same phase, and the product of the voltage and the current The applied power is the matching line 3
Will be the largest above.

Therefore, by connecting the communication device 4 to the feed point 32 located at λ / 8 from the connection portion 31, the communication device 4 can supply the maximum power to the antenna element 2, or It can receive with maximum power.

Further, since the matching line 3 is configured as a characteristic impedance line, the matching line becomes a stable matching line, and the influence of external radio waves due to interference and radiation from other lines is eliminated.

As shown in the embodiment, the matching line 3
In the case of the structure in which the metal strip line 36 and the ground conductor 371 are provided on the plate-shaped dielectric substrate 35, the size and thickness can be reduced.

4 to 6 show another embodiment of the antenna device according to the present invention. In the drawings, the same components as those in FIGS. 1 to 3 are denoted by the same reference numerals. 4 to 6 show specific embodiments of the antenna element 2. FIG. The antenna element 2 has a rod shape in the embodiment of FIG. 4 and a helical shape in the embodiment of FIG.
In this embodiment, the shape is zigzag. Although not shown, a composite antenna element obtained by combining the antenna elements 2 of FIGS. 4 to 6 can be used.

FIG. 7 is a plan view showing still another embodiment of the antenna device according to the present invention. In this embodiment, the metal strip line 36 constituting the matching line 3 is formed in a zigzag manner. With such a structure, the length direction of the dielectric substrate 35 can be shortened and the size can be reduced. Overall length L of matching line 3
(= Λ / 2) and the distance (λ / 8) from the connection point 31 to the feeding point 32 are given by the total length of the path P1 passing through the width center of the metal strip line 36. In the case of the embodiment, the total length L (λ / 2) of the matching line 3 is λ / 2 ≒ L1 + L2 + L3 + L4 + L5 + L6 + L7 +
L8. Further, the distance (λ / 8) from the connection point 31 to the feeding point 32 is λ / 8 ≒ L1 + L2 + L3. However, it is an approximate value.

The housing 1 contains at least one selected from the antenna element 2 shown in FIGS. 4 to 6 or its composite antenna element.

In the antenna device having the structure shown in FIG. 7, the voltage distribution characteristic V and the current distribution characteristic I as described with reference to FIG.

FIG. 8 is a plan view showing still another embodiment of the antenna device according to the present invention. In this embodiment, the metal strip line 36 constituting the matching line 3 is formed in a zigzag manner. With such a structure, the length direction of the dielectric substrate 35 can be shortened and the size can be reduced.

FIG. 9 is a perspective view showing still another embodiment of the antenna device according to the present invention, and FIG. 10 is a sectional view of the antenna device shown in FIG. In the embodiment, the dielectric substrate 35
, A metal strip line 36 is provided.
The illustrated metal strip line 36 is straight. In addition, it includes two ground conductors 371 and 372, and the two ground conductors 371 and 372 are provided on the front and back surfaces of the dielectric substrate 35 on both sides of the metal strip line 36, respectively. The ground conductors 371 and 372 are
May be provided inside.

Further, in the embodiment, the antenna element 2 is buried inside the dielectric substrate 35. Antenna element 2
Is wound helically.

Metal strip line 36 and ground conductor 37
It is desirable that the dielectric substrate 351 supporting the first and second elements 372 and the dielectric substrate 352 supporting the antenna element 2 are made of dielectric materials having different dielectric constants. For example, assuming that the dielectric substrate 35 is composed of an organic dielectric material, the dielectric substrate 351 is composed of a tetrafluoroethylene resin, the dielectric substrate 352 is composed of an epoxy resin or the like. When the dielectric substrate 35 is made of an inorganic dielectric material, the dielectric substrate 351 is made of CaTiO ₃ , BaXTiO
_The dielectric base 352 can be formed of another ceramic material having a low dielectric constant, such as a tri-based or CaTiO ₃ -SrTiO ₃ -based barium titanate-based ceramic material. BaXTiO ₃
In the system, X is typically Ca, Sr, Mg, etc.

The structure in which the metal strip line 36 and the antenna element 2 are embedded in the dielectric substrate 35 made of the organic dielectric material or the inorganic dielectric material described above can be easily applied by applying the existing lamination technology. realizable.

The electric wavelength λ of the matching line 3 depends on the dielectric substrate 3
Due to the relative permittivity of 51, it becomes shorter than the actual size,
The length λ / 2 of the matching line 3 is also determined by using the electric wavelength λ calculated from the relative permittivity of the dielectric substrate 351 as λ / 2 and λ / 2.
/ 8 is calculated.

The feed point 32 is provided at a position λ / 8 from the antenna connection portion 31 on the metal strip line 36. The power supply point 32 is led out to the outer surface of the dielectric substrate 351 through a power supply path 34 provided through the dielectric substrate 351, and the external terminal 3 provided on the outer surface of the dielectric substrate 351 is provided.
8 is connected. The external terminal 38 is provided with a gap 373 between the external terminal 38 and the ground conductor 371 and is separated therefrom.

The antenna element 2 does not need to be filled with a dielectric material around it. However, for fixing and miniaturization, the antenna element 2 is supported by a dielectric substrate 352 made of a material having a relatively low relative dielectric constant. It is.

The features of the embodiment shown in FIGS. 9 and 10 are as follows.
It can be used as a surface mount chip component. Also,
Since the ground conductors 371 and 372 are arranged on both sides of the metal strip line 36 that forms the matching line 3, the ground conductors 371 and 372 function as shield conductors for the metal strip line 36. Therefore, an antenna device stable against noise can be obtained.

FIG. 11 is a perspective view showing still another embodiment of the antenna device according to the present invention, and FIG. 12 is a sectional view of the antenna device shown in FIG. In the figures, FIG. 9 and FIG.
The same components as those described above are denoted by the same reference numerals. In the embodiment, the metal strip line 36 is serpentine. Also, two ground conductors 371, 3
Reference numerals 72 are provided on the dielectric substrate 351 on both sides of the metal strip line 36.

Further, also in this embodiment, the antenna element 2
Are embedded inside the dielectric substrate 352. The antenna element 2 is formed in a zigzag.

The metal strip line 36 and the antenna element 2 are connected to each other at the connection part 31.
A feed point 32 is set at a position of about λ / 8 from the connection part 31, and a feed path 34 is connected to the feed point 32. The power supply point 32 is drawn out of the dielectric substrate 35 by a power supply path 34 attached to a side surface of the dielectric substrate 351.

The embodiment shown in FIGS. 11 and 12 has the same operation and effect as the embodiment shown in FIGS. 9 and 10. A metal strip line 36 and a ground conductor 371;
A dielectric substrate 351 supporting the 372 and an antenna element 2
As described above, it is desirable that the dielectric substrate 352 that supports the above is made of dielectric materials having different dielectric constants from each other.

FIG. 13 is a perspective view showing still another embodiment of the antenna device according to the present invention. In the figure, the same components as those in FIGS. 11 and 12 are denoted by the same reference numerals. In the embodiment, the metal strip line 3
6 is formed in a zigzag shape. The two ground conductors 371 and 372 are provided on the dielectric substrate 35 on both sides of the metal strip line 36. The antenna element 2 is buried inside the dielectric substrate 35. The antenna element 2 is helically wound around the dielectric substrate 35.

The metal strip line 36 and the antenna element 2 are connected to each other at the connection part 31.
A feed point 32 is set at a position of about λ / 8 from the connection part 31, and a feed path 34 is connected to the feed point 32. The power supply path 34 is a power supply path 3 attached to a side surface of the dielectric substrate 35.
By 4, it is drawn out of the dielectric substrate 35. Although not shown, the dielectric substrate 35 is divided into a dielectric substrate that supports the metal strip line 36 and the ground conductors 371 and 372 and a dielectric substrate that supports the antenna element 2. Is desirably composed of dielectric materials having different dielectric constants, as described above. In the case of the embodiment shown in FIG.
The same operation and effect as those of the embodiment shown in FIG.

FIG. 14 is a diagram for explaining the definition of the "length" of the matching line 3 in the embodiment shown in FIGS. That is, the total length L (= λ / 2) of the matching line 3 and the distance (λ / 8) from the connection point 31 to the feeding point 32 are given by the total length of the path P1 passing through the center of the width of the metal strip line 36. First, the total length L (λ / 2) of the matching line 3 is λ / 2 ≒ L1 + L2 + L3 + L4 + L5 + L6 + L7. Next, the distance (λ / 8) from the connection point 31 to the feeding point 32 is λ / 8 ≒ L1 + L2 + L3. However, it is an approximate value.

FIG. 15 is a diagram showing a configuration of an antenna device according to the present invention and a configuration of an antenna device as a comparative example. FIG.
(A) shows an embodiment of the antenna device according to the present invention, in which the length of the matching line 3 is λ / 2, and the feeding point 32 is located at λ / 8 from the connection portion 31 between the matching line 3 and the antenna element 2. , And is connected to the communication device 4 via the power supply path 34 at the power supply point 32.

FIG. 15B is a view showing Comparative Example 1, in which the length of the matching line 3 is λ / 2, and the feeding point is located at λ / 4 from the connection 31 between the matching line 3 and the antenna element 2. The communication device 4 is connected to the power supply point 32 via a power supply path 34.

FIG. 15C shows a comparative example 2, in which the length of the matching line 3 is λ / 4, a feed point 32 is provided at the open end of the matching line 3, and a feed line 34 is provided at the feed point 32. The communication device 4 is connected via the.

FIG. 15D shows a comparative example 3, in which a feed line 34 is directly connected to a feed point 32 set at one end of the antenna element 2 to feed power without using a matching line. It has become.

FIG. 16 shows a directional gain graph of each of the antenna devices of FIGS. 15 (a) to 15 (d). In the figure,
Curve (a) is the directivity gain characteristic of the embodiment according to the present invention (see FIG. 15A), and curve (b) is Comparative Example 1 (FIG. 15).
(B)), the directional gain characteristic, and the curve (c) are Comparative Example 2.
The directional gain characteristic of FIG. 15C and the curve (d) show the directional gain characteristic of Comparative Example 3 (see FIG. 15D).

As is apparent from FIG. 16, in the case of the embodiment according to the present invention, the average directivity gain is about -2.5 (see the characteristic (a)). On the other hand, the average directivity gains of Comparative Examples 1 to 3 are about −22.5 (see the characteristic (b)) in Comparative Example 1, and about −8.5 (characteristic (c)) in Comparative Example 2. Comparative Example 3 is about -11.5 (see characteristic (d)). As can be seen from the results, according to the present invention, it is possible to obtain an antenna device having extremely excellent directivity gain characteristics.

FIG. 17 is a plan view showing still another embodiment of the antenna device according to the present invention, and FIG. 18 is a view 18-18 of FIG.
It is sectional drawing along the line. In the drawings, the same components as those in FIGS. 1 to 15 are denoted by the same reference numerals. The feature of this embodiment is that the matching line 3 is a coaxial line. The coaxial line is a line having an inherent characteristic impedance, and many of the lines have a small electric loss, so that a high-quality matching line 3 can be realized.

In the embodiment shown in FIGS. 17 and 18, the matching line 3 formed of a coaxial line has a length L of λ / 2.
It has become. Antenna element 2 housed in housing 1
And a connection point 31 with the matching line 3, there is a feed point 32 at a position of λ / 8, and a feed path 34 for connecting to a communication device is connected to the feed point 32. The other end opposite to the connecting portion 31 is an open end 33.

The coaxial line forming the matching line 3 includes a dielectric layer 350 and a ground conductor 370 around a center conductor 360.
Are sequentially arranged coaxially. One end of the center conductor 360 forms a connection portion 31 with the antenna element 2, and the other end is an open end 33. A coaxial line is provided at a feed point 32 at a position λ / 8 from the connection portion 31.
A conductor 340 penetrating through the dielectric layer 350 is provided. One end of the conductor 340 is connected to the center conductor 360, and the other end is connected to the power supply path 34 formed in the support substrate 7. The housing 1 housing the matching line 3 and the antenna element 2 formed of a coaxial line is mounted on a support substrate 7. A ground conductor 8 is provided on the mounting surface of the support substrate 7. The ground conductor 370 of the coaxial line is connected to the ground conductor 8 of the support substrate 7 by solder 373, and is kept at the ground potential.

FIG. 19 is a diagram for explaining the operation of the antenna device shown in FIGS. Also in the case of the matching line 3 using a coaxial line, there is no difference from the operation characteristics of FIG. 3 using a metal strip line. That is, as shown in FIG. 19, in use, the communication device 4 is connected to the power supply path 34 connected to the power supply point 32.

As described above, the total length L of the matching line 3 is
Since the operating frequency wavelength (electrical wavelength) λ is set to λ / 2, the resonant standing wave of λ / 2 is
Present on. In this case, the current distribution characteristic I on the matching line 3
The current value becomes substantially zero at one end of the matching line 3 and the other end which is the open end 33, and the sinusoidal distribution characteristic is maximized at the center C1 of the matching line 3. The voltage distribution characteristic V becomes maximum (opposite phases) at one end of the matching line 3 which is the connection 31 with the antenna element 2 and the other end which is the open end 33, and becomes the center of the matching line 3. It shows a sinusoidal distribution characteristic that becomes almost zero at C1. Due to the current distribution characteristic I and the voltage distribution characteristic V described above, the antenna element 2 and the matching line 3
At the position of λ / 8 from the connection portion 31 of the above, the voltage and the current have the same phase, and the power given by the product of the voltage and the current becomes maximum on the matching line 3.

Therefore, by connecting the communication device 4 to the feeding point 32 located at λ / 8 from the connection portion 31, the communication device 4 can supply the maximum power to the antenna element 2, or It can receive with maximum power.

Further, since the matching line 3 is formed as a coaxial line, the matching line becomes a stable matching line, and the influence of external radio waves due to interference and radiation from other lines is eliminated.

FIG. 20 is a plan view showing still another embodiment of the antenna device according to the present invention. In the figure, FIG.
The same components as those shown in FIG. 19 are denoted by the same reference numerals. The features of this embodiment are:
That is, the matching line 3 formed of a coaxial line is bent to shorten the length direction. The bending point is arbitrary. Also in this embodiment, the matching line 3 composed of a bent coaxial line has a total length of λ.
/ 2, and the distance from the connection part 31 to the feeding point 32 is λ
/ 8. Even with such a structure, the voltage distribution characteristic V and the current distribution characteristic I shown in FIG.

FIG. 21 is a view showing still another embodiment of the antenna device according to the present invention, and FIG. 22 is a partial sectional view taken along line 22-22 of FIG. In this embodiment, the matching line 3
Has a length of λ / 4 with respect to the working frequency wavelength λ. One end of the matching line 3 is connected to the antenna element 2 at the connection part 31, and the other end 33 is short-circuited by the short-circuit conductor 39. The feed point 32 for the matching line 3 is connected to a position approximately λ / 8 from the connecting portion 31 which is one end of the matching line 3.

In the above embodiment, the total length L of the matching line 3
Perform a resonance operation with a standing wave of λ / 4. In this case, as shown in FIG. 22, the current distribution characteristic I on the matching line 3 is such that the current value is substantially zero at one end of the matching line 3 which is the connection 31 with the antenna element 2. In addition, it shows a distribution characteristic of a half-sinusoidal shape which is maximum at the other end of the short-circuit conductor 39. The voltage distribution characteristic V indicates that the matching line 3 which is the connection 31 with the antenna element 2
At the other end with the short-circuit conductor 39,
It shows a distribution characteristic of a half-sinusoidal shape with almost zero. Due to the current distribution characteristics I and the voltage distribution characteristics V described above, at the feed point 32 located at λ / 8 from the connection 31 between the antenna element 3 and the matching line 3, the voltage distribution characteristics V and the current distribution characteristics I ,
In phase, the power given by the product of voltage and current is
It becomes maximum on the matching line 3.

As described above, since the voltage distribution characteristic V and the current distribution characteristic I have the same phase in the matching line 3 and the product of the two becomes maximum, the power supply point 32 is provided at this position to transmit and receive.
With the connection part for reception, transmission and reception with maximum power without phase shift becomes possible.

Further, since the length L of the matching line 3 is λ / 4, the size can be reduced. Further, since the matching line 3 is a characteristic impedance line, the matching line becomes a stable matching line, and the influence of external radio waves due to interference and radiation from other lines is eliminated.

In the embodiment shown in FIGS. 21 and 22, the matching line 3 is constituted by a combination of the metal strip line 36, the dielectric substrate 35 and the ground conductor 371.
It goes without saying that the configuration may be made using a coaxial line.

FIG. 23 is a perspective view showing still another embodiment of the antenna device according to the present invention, and FIG. 24 is a sectional view of the antenna device shown in FIG. In the embodiment, a metal strip line 36 is provided inside a dielectric substrate 35. The illustrated metal strip line 36 is straight. The two ground conductors 371 and 372 are provided on the front and back surfaces of the dielectric substrate 35 on both sides of the metal strip line 36, respectively. The antenna element 2 is buried inside the dielectric substrate 35 and wound helically.

The other end of the metal strip line 36 opposite to the one end where the connection portion 31 is located is short-circuited to the ground conductors 371 and 372 by the short-circuit conductor 39. The length L from the connection part 31 which is one end of the metal strip line 36 to the other end where the short-circuit conductor 39 exists is λ / 4. Also,
The feed point 32 is set at a position of λ / 8 from the connection part 31. The power supply point 32 is led out to the outer surface of the dielectric substrate 351 through a power supply path 34 provided through the dielectric substrate 351, and is connected to an external terminal 38 provided on the outer surface of the dielectric substrate 351. The external terminal 38 is a ground conductor 37
1 and a gap 373 is provided therebetween.

The embodiment shown in FIGS. 23 and 24
Except for the short-circuit conductor 39, it does not differ from the embodiment shown in FIGS. Therefore, FIGS. 9 and 10
All the descriptions related to the embodiment of FIG. Although not shown in the drawings, even if the short-circuit type is used, FIGS.
It will be apparent to those skilled in the art that the embodiments shown in FIGS. 17 to 20 can be modified.

FIG. 25 is a plan view showing another embodiment of the antenna device according to the present invention. In this embodiment, the antenna element 2 formed of a linear metal strip line is formed on one surface of the dielectric substrate 35, and matching is performed in a direction perpendicular to the antenna element 2 at a connection portion 31 at one end of the antenna element 2. A metal strip line 36 constituting the line 3 is arranged. The total length L of the metal strip line 36 is λ / 2.
The feeding point 32 is set at a position of λ / 8 from the connection portion 31. A power supply path 34 is connected to the power supply point 32. Although not shown, a ground conductor is provided on the rear surface side of the dielectric substrate 35 at a position facing the metal strip line 36.

FIG. 26 is a perspective view showing still another embodiment of the antenna device according to the present invention. This embodiment is shown in FIG.
Discloses an effective means when the dielectric substrate 35 is made of a flexible sheet in the antenna device shown in FIG. The flexible sheet is made of a flexible dielectric material, for example, an organic dielectric material. That is, the dielectric substrate 3
5 is made of a flexible dielectric material, and the dielectric substrate 35 is wound along the length direction of the metal strip line 2 constituting the antenna element 2 and crushed if necessary. Thus, a miniaturized antenna device can be obtained. The antenna element 2 has a spiral shape. When the dielectric substrate 35 is wound, the metal strip line 36 constituting the matching line 3 appears on the outermost surface side while maintaining the linear arrangement.

FIG. 27 is a perspective view showing another embodiment of the antenna device according to the present invention, and FIG. 28 is a developed plan view of the antenna device shown in FIG. In this embodiment, the antenna element 2 is helically wound. In FIG. 27, an antenna element 2 is provided obliquely along a longitudinal direction on a dielectric substrate 35 made of a flexible sheet.
The metal strip line 36 is provided on one side in the longitudinal direction of the dielectric base 35 made of a flexible sheet in a width direction orthogonal to the longitudinal direction, and one end is connected to one end of the antenna element 2. The dielectric substrate 35 is wound along its longitudinal direction and crushed if necessary. As a result, FIG.
8 can be obtained.

Although not shown, it is obvious that the technology shown in FIGS. 25 to 28 can be applied to a short-circuit type antenna device.

FIG. 29 is a partial sectional view showing still another embodiment of the antenna device according to the present invention. One end of the matching line 3 is connected to the antenna element 2 via a capacitive element 9, specifically, a capacitor. The capacitive element 9 can be constituted by a capacitor using the dielectric substrate 35 or a chip capacitor.

[0071]

As described above, according to the present invention, the following effects can be obtained. (A) An antenna device capable of operating an antenna element at a maximum power point can be provided. (B) It is possible to provide an antenna device that is hardly affected by external radio waves.

[Brief description of the drawings]

FIG. 1 is a plan view of an antenna device according to the present invention.

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

FIG. 3 is a diagram illustrating an operation principle in a use state of the antenna device according to the present invention illustrated in FIGS. 1 and 2;

FIG. 4 is a partial sectional view showing another embodiment of the antenna device according to the present invention.

FIG. 5 is a partial sectional view showing still another embodiment of the antenna device according to the present invention.

FIG. 6 is a partial sectional view showing still another embodiment of the antenna device according to the present invention.

FIG. 7 is a plan view showing still another embodiment of the antenna device according to the present invention.

FIG. 8 is a plan view showing still another embodiment of the antenna device according to the present invention.

FIG. 9 is a perspective view showing still another embodiment of the antenna device according to the present invention.

FIG. 10 is a sectional view of the antenna device shown in FIG. 9;

FIG. 11 is a perspective view showing still another embodiment of the antenna device according to the present invention.

12 is a cross-sectional view of the antenna device shown in FIG.

FIG. 13 is a perspective view showing still another embodiment of the antenna device according to the present invention.

FIG. 14 is a diagram for explaining the definition of the “length” of the matching line in the embodiment shown in FIGS. 11 to 13;

FIG. 15 is a diagram showing a configuration of an antenna device according to the present invention and a configuration of an antenna device as a comparative example.

16 is a graph showing the directivity gain of each antenna device shown in FIG.

FIG. 17 is a plan view showing still another embodiment of the antenna device according to the present invention.

18 is a sectional view taken along the line 18-18 in FIG.

FIG. 19 is a diagram illustrating the operation of the antenna device illustrated in FIGS. 17 and 18.

FIG. 20 is a plan view showing still another embodiment of the antenna device according to the present invention.

FIG. 21 is a plan view showing still another embodiment of the antenna device according to the present invention.

FIG. 22 is a partial sectional view taken along the line 22-22 in FIG. 21;

FIG. 23 is a perspective view showing still another embodiment of the antenna device according to the present invention.

24 is a cross-sectional view of the antenna device shown in FIG.

FIG. 25 is a plan view showing another embodiment of the antenna device according to the present invention.

FIG. 26 is a perspective view showing still another embodiment of the antenna device according to the present invention.

FIG. 27 is a plan view showing another embodiment of the antenna device according to the present invention.

FIG. 28 is a perspective view showing an antenna device obtained from the antenna device shown in FIG. 27;

FIG. 29 is a partial sectional view showing still another embodiment of the antenna device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Antenna element 3 Matching line 31 Connection part with antenna element 32 Feeding point 33 Open end 34 Feeding path 35 Dielectric substrate 36 Metal strip line 371, 372 Ground conductor 39 Short-circuit conductor

Claims (27)

[Claims] 1. An antenna device including an antenna element and a matching line, wherein the matching line is approximately λ when a working frequency wavelength is λ.
An antenna device having a length of / 2, one end connected to the antenna element, the other end open, and a feeding point set at a position of about λ / 8 from the one end. 2. An antenna device including an antenna element and a matching line, wherein the matching line is approximately λ when a working frequency wavelength is λ.
An antenna device having a length of / 4, one end connected to the antenna element, the other end short-circuited, and a feeding point set at a position of about λ / 8 from the one end. 3. The antenna device according to claim 1, wherein the matching line includes a dielectric substrate, a metal strip line, and a ground conductor. The antenna device, wherein the ground conductor is opposed via the dielectric substrate. 4. The antenna device according to claim 3, wherein the metal strip line and the ground conductor are supported by a dielectric substrate. 5. The antenna device according to claim 4, wherein the metal strip line and the ground conductor are provided on a front surface and a back surface of the dielectric base, respectively. 6. The antenna device according to claim 4, wherein the metal strip line is provided inside the dielectric substrate. 7. The antenna device according to claim 6, wherein the ground conductor is provided on the dielectric substrate on both sides of the metal strip line. 8. The antenna device according to claim 3, wherein the metal strip line forms a curved path. 9. The antenna device according to claim 4, wherein the antenna element is supported by the dielectric base. 10. The antenna device according to claim 9, wherein the antenna element is embedded in the dielectric base. 11. The antenna device according to claim 9, wherein the dielectric base supporting the antenna element and the dielectric supporting the metal strip line and the ground conductor. An antenna device in which a body substrate is made of dielectric materials having different dielectric constants. 12. The antenna device according to claim 9, wherein the antenna element forms a curved road. 13. The antenna device according to claim 8, 9 or 10, wherein the antenna element is helically wound. 14. The antenna device according to claim 1, wherein the matching line is a coaxial line. 15. The antenna device according to claim 13, wherein the coaxial line forms a curved path. 16. The antenna device according to claim 3, wherein the dielectric base is made of a flexible sheet. 17. The antenna device according to claim 16, wherein the flexible sheet is wound or folded. 18. The antenna device according to claim 1, wherein the one end of the matching line is connected to the antenna element via a capacitive element. 19. A matching line used in an antenna device, having a length of about λ / 2 when an operating frequency wavelength is λ, one end constituting an antenna element connection end, and the other end being open. A matching line for an antenna device, wherein a feeding point is set at a position of about λ / 8 from the one end. 20. A matching line used in an antenna device, having a length of about λ / 4 when an operating frequency wavelength is λ, one end constituting an antenna element connection end, and the other end short-circuited. A matching line for an antenna device, wherein a feeding point is set at a position of about λ / 8 from the one end. 21. The matching line for an antenna device according to claim 19, further comprising: a dielectric substrate, a metal strip line, and a ground conductor. And a matching line for the antenna device, wherein the grounding conductor faces through the dielectric substrate. 22. The matching line for an antenna device according to claim 21, wherein the metal strip line and the ground conductor are supported by a dielectric substrate. 23. The matching line for an antenna device according to claim 22, wherein the metal strip line and the ground conductor are provided on a front surface and a back surface of the dielectric substrate, respectively. . 24. The matching line for an antenna device according to claim 22, wherein the metal strip line and the ground conductor are provided inside the dielectric substrate. 25. The method according to claim 19,20,21,22,23.
25. The matching line for an antenna device according to any one of claims 24, wherein the metal strip line is a curved path. 26. The matching line for an antenna device according to claim 19, wherein the matching line is a coaxial line. 27. The matching line for an antenna device according to claim 26, wherein the coaxial line is a curved line. Matching line for antenna device.