JP2002151930A - Antenna structure and radio equipment provided with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of an antenna by which the antenna gain can be improved. SOLUTION: A radiation electrode 3 of a microstrip line form is formed in a non-ground area 4 of a printed circuit board 2 made of a dielectric material. A segmented part 10 consisting of a gap is interposed into the radiation electrode 3. A dielectric base chip 11 is bridged over radiation electrodes 10a and 10b at both ends of the segmented part 10 and a connection use transmission line 12 conductively connects the radiation electrodes 10a and 10b at both ends of the segmented part 10. Since the interposed part of the connection use transmission line 12 in the radiation electrode 3 is parted from a printed circuit board 2, the interposed part is not affected by a dielectric loss tangent tanδ of the printed circuit board 2. Furthermore, variably controlling the dielectric loss tangent tanδ of the dielectric base chip 11 can variably control a state of the current distribution of the interposed part of the connection use transmission line 12 so as to improve the deterioration in the antenna characteristic due to the dielectric loss tangent tanδ of the printed circuit board 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio device such as a portable telephone and an antenna structure built in the radio device.

[0002]

2. Description of the Related Art FIG. 9 schematically shows an example of an antenna structure built in a wireless device such as a portable telephone.
The antenna structure 1 shown in FIG. 9 includes a circuit board 2 of a wireless device made of a dielectric material and a microstrip line-shaped radiation electrode 3. That is, in the example shown in FIG. 9, a non-ground area 4 is formed at the edge of the circuit board 2, and the microstrip line-shaped radiation electrode 3 is formed in the non-ground area 4 by, for example, etching. It is formed by a forming technique.

An area of the circuit board 2 excluding the non-ground area 4 is a ground area in which a ground electrode 5 equivalent to the ground is formed. Components 6 constituting a transmission / reception circuit are mounted.

[0004] One end 3a of the radiation electrode 3 is an open end, the other end 3b is a feed end, and a through-hole 7 is formed in the feed end 3b. Reference numeral 3b is conductively connected to a transmitting / receiving circuit via the through hole 7 and a circuit pattern (not shown) formed on the circuit board 2. For example, when a signal is supplied from the transmission / reception circuit to the power supply end 3b, the radiation electrode 3 performs an antenna operation by supplying the signal.

[0005]

In the antenna structure 1 shown in FIG. 9, the radiation electrode 3 is formed directly on the circuit board 2 over the entire length. Therefore, the antenna characteristics of such an antenna structure 1 are easily affected by the dielectric constant and the dielectric loss tangent tan δ of the circuit board 2.

However, the circuit board 2 has a dielectric constant and a dielectric loss tangent of its constituent materials in consideration of only the antenna characteristics.
Since tan δ is not determined, the gain of the antenna structure 1 may be deteriorated by the influence of the dielectric constant and the dielectric loss tangent tan δ of the constituent material of the circuit board 2.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an antenna structure in which the influence of a radiation electrode from a circuit board can be suppressed to a small extent and antenna characteristics can be easily improved. And a wireless device having the same.

[0008]

Means for Solving the Problems In order to achieve the above object, the present invention has the following structure to solve the above problems. That is, a first invention is an antenna structure in which a microstrip line-shaped radiation electrode is formed on a surface of a circuit board made of a dielectric material,
The radiation electrode is provided with a dividing portion composed of a gap, and a chip-shaped dielectric substrate that is disposed so as to span the radiation electrodes at both ends of the divided portion; a chip-shaped dielectric substrate formed on the chip-shaped dielectric substrate, and And a connection transmission line for electrically connecting the radiation electrodes at both ends of the dividing portion.

A second aspect of the present invention has the configuration of the first aspect, wherein the chip-shaped dielectric substrate is made of a material having a dielectric loss tangent tan δ smaller than that of the circuit board.

A third aspect of the present invention has the configuration of the first or second aspect, wherein one end of the radiation electrode forms a power supply end to which a signal is supplied, and the other end forms an open end. In addition, a parasitic radiation electrode that is disposed at an interval from the open end of the radiation electrode and that is magnetically joined to the radiation electrode is formed.

A fourth aspect of the present invention is directed to the first, second or third aspect.
One end side of the radiation electrode is a feed end to which a signal is supplied, and the dividing portion of the radiation electrode has a length from the feed end of the radiation electrode equal to the total length of the radiation electrode. About 1
/ 4 or less.

According to a fifth aspect of the present invention, there is provided the structure of any one of the first to fourth aspects of the present invention, wherein the chip-shaped dielectric substrate is made of a dielectric material having a relative dielectric constant of 10 or less. It is characterized by:

In a sixth aspect, the first, third or fourth aspect of the invention is provided.
The invention has a configuration in which air having a relative dielectric constant of 1 is disposed in the divided portion of the radiation electrode instead of the chip-shaped dielectric substrate, and between the radiation electrodes at both ends of the divided portion. The connection transmission line for conducting the connection is constituted by a conductor plate member, and the conductor plate member is characterized in that an area other than the connection portion with the radiation electrode is in a form floating from the circuit board. Have been.

According to a seventh aspect of the present invention, there is provided a radio apparatus according to the first to sixth aspects.
The antenna structure according to any one of the inventions is provided.

In the invention having the above configuration, for example, when a signal is supplied to the power supply end of the radiation electrode, the signal is conducted from the power supply end to the open end through the connection transmission line. By this signal supply, the radiation electrode performs an antenna operation.

As described above, the permittivity and the dielectric loss tangent tanδ of the circuit board are determined in consideration of various points, and the permittivity and the dielectric loss tangent tanδ of the circuit board are determined from the viewpoint of antenna characteristics. Sometimes it is not appropriate, and in this case, there is a problem that the antenna characteristics are deteriorated.

On the other hand, in the present invention, a transmission line for connection formed on, for example, a chip-shaped dielectric substrate is interposed in the radiation electrode. Thus, the connection transmission line portion of the radiation electrode is formed apart from the circuit board, and the chip-shaped dielectric substrate on which the connection transmission line is formed is:
Considering only the antenna characteristics, it is possible to determine the dielectric constant and the dielectric loss tangent tanδ of the constituent material,
By varying the dielectric constant and the dielectric loss tangent tanδ of the chip-shaped dielectric substrate, the electrical characteristics of the connection transmission line of the chip-shaped dielectric substrate are varied, thereby varying the current distribution state of the radiation electrode. Thus, the antenna characteristics can be variably controlled.

From this, it is possible to improve the antenna gain by appropriately setting the dielectric constant and the dielectric loss tangent tanδ of the above-mentioned chip-shaped dielectric substrate so that the antenna characteristics are in an appropriate state required. Becomes

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1A is a plan view showing a characteristic antenna structure in the wireless device of the first embodiment.
FIG. 1B is an enlarged view of a region Z surrounded by a dotted line in FIG. 1A, which is characteristic of the antenna structure of the first embodiment, and FIG. 1) is a perspective view of a region Z shown in FIG. 1), and FIG.
The chip-shaped dielectric substrate 11 shown in (c) is shown in a developed state. 2 (a) shows the chip-shaped dielectric substrate 11 and the radiation electrode 3 shown in FIG. 1 (c) in an exploded state, and FIG. 2 (b) shows the mounting of the chip-shaped dielectric substrate 11. The state is shown. Note that the wireless device has various configurations, and in the first embodiment, any configuration other than the antenna structure in the wireless device can take any configuration. Here, the wireless device other than the antenna structure is used. The description of the device configuration is omitted. In the first embodiment, in the description of the antenna structure, the same components as those in the conventional example are denoted by the same reference numerals, and the overlapping description of the common portions will be omitted.

As described above, in the conventional configuration in which the radiation electrode 3 is formed directly on the circuit board 2 over the entire length, the dielectric loss tangent tan δ of the circuit board 2 and the antenna characteristic of the antenna structure 1 Is different from the dielectric loss tangent tan δ for achieving the optimum state, the antenna characteristics may be significantly deteriorated due to the dielectric loss tangent tan δ of the circuit board 2. The inventor of the present invention separates the maximum current distribution portion of the radiation electrode 3 where the current distribution most susceptible to the dielectric loss tangent tan δ of the circuit board 2 is most distant from the circuit board 2 and sets the current distribution state of the maximum current distribution portion , The antenna characteristics of the radiation electrode 3 can be greatly improved, and by paying attention to this, a configuration capable of preventing the deterioration of the antenna characteristics due to the dielectric loss tangent tan δ of the circuit board 2 has been devised.

That is, a characteristic of the first embodiment is that, as shown in FIGS. 1 (b) and 2 (a), the radiation electrode 3 has a dividing portion 10 at a maximum current distribution portion.
Are formed by a gap, and the radiation electrode portions 10a and 10b at both ends of the dividing portion 10 are connected to the chip-shaped dielectric substrate 1
That is, the connection is made conductive by the connection transmission line 12 formed in the step S1. Other configurations are almost the same as those of the conventional example. In the first embodiment, as in the prior art, the ground region 5 of the circuit board 2 is also provided.
Are mounted with various components, but the components are not shown in FIG.

The radiation electrode 3 shown in the first embodiment
In the first embodiment, the maximum current distribution region is a region in which the length from the feeding end 3b of the radiation electrode 3 is not more than about 1/4 of the entire length of the radiation electrode 3. 3 is formed in a region adjacent to the feeding end 3b whose length from the feeding end 3b is about １ ／ or less of the entire length of the radiation electrode 3.

In the first embodiment, the chip-shaped dielectric substrate 11 mounted on the dividing portion 10 has a rectangular parallelepiped shape, and the chip-shaped dielectric substrate 11 has a structure shown in FIG. The connection transmission line 12 extending from one end of the bottom surface 11f to the other end of the bottom surface 11f through the front end surface 11c, the upper surface 11a, and the rear end surface 11e in this order is formed by a film formation technique such as sputtering. ing.

In the first embodiment, the chip-shaped dielectric substrate 11 is arranged so as to span the radiation electrode portions 10a and 10b at both ends of the dividing portion 10, and the solder is provided as shown in FIG. 13 and the like. Thereby, both ends of the connection transmission line 12 are respectively connected to the radiation electrode portions 1 at the ends of the dividing portion 10.
The radiating electrode portions 10a and 10b at both ends of the dividing portion 10 are conductively connected to 0a or 10b by the connecting transmission line 12.

In the first embodiment, the circuit board 2
Since the antenna structure 1 has a dielectric loss tangent tan δ larger than the dielectric loss tangent tan δ for achieving an optimum state, the antenna characteristic of the antenna structure 1 is deteriorated due to the dielectric loss tangent tan δ of the circuit board 2. In the first embodiment, the chip-shaped dielectric substrate 11 is made of a dielectric material having a dielectric loss tangent tan δ smaller than that of the circuit board 2 for antenna characteristic compensation.

In the first embodiment, the dielectric material constituting the chip-shaped dielectric substrate 11 also has a feature that the relative dielectric constant is 10 or less. Therefore, the electrical length of the connection transmission line 12 formed on the chip-shaped dielectric substrate 11 can be increased, and the chip-shaped dielectric substrate 11 can be reduced in size.

In the first embodiment, for example, the radiation electrode 3 is transmitted from the transmission / reception circuit of the wireless device through the through hole 7.
, The signal is conducted from the feeding end 3b of the radiation electrode 3 through the connection transmission line 12 to the open end 3a. By this signal supply, the radiation electrode 3 performs an antenna operation.

According to the first embodiment, the radiation electrode 3
A dividing portion 10 formed of a gap is formed in the substrate, and the radiation electrode portions 10a and 10b at both ends of the dividing portion 10 are electrically connected by a connection transmission line 12 formed on a chip-shaped dielectric substrate 11.

As a result, the portion of the connection transmission line 12 in the radiation electrode 3 is formed apart from the circuit board 2, and the connection transmission line 12 is provided with a dielectric constant and a dielectric tangent tan δ of the circuit board 2. Will not be affected.

In addition, the circuit board 2 is, as described above,
The dielectric constant and the dielectric loss tangent tanδ are determined in consideration of various points, whereas the dielectric constant and the dielectric loss tangent tanδ of the chip-shaped dielectric substrate 11 are determined only in consideration of the antenna characteristics. By varying the dielectric constant and the dielectric loss tangent tan δ of the chip-shaped dielectric substrate 11, the electrical characteristics of the connection transmission line 12 formed on the chip-shaped dielectric substrate 11 can be changed. It can be variably controlled. From this, it is possible to change the current distribution state of the radiation electrode 3 by changing the electric characteristics of the transmission line 12 for connection, and to set the antenna characteristics to an appropriate state.

For example, in a conventional structure in which the radiation electrode 3 is formed directly on the circuit board 2 over the entire length, the current distribution of the radiation electrode 3 is in a distribution state as shown by a solid line A in FIG. In contrast, in the configuration of the first embodiment,
Since the chip-shaped dielectric substrate 11 and the transmission line 12 for connection are interposed in the radiation electrode 3, the chain line B in FIG.
As shown in (1), the current distribution of the radiation electrode 3 in the interposed portion of the chip-shaped dielectric substrate 11 and the connection transmission line 12 becomes larger than in the conventional structure.

As described above, since the current distribution of the radiation electrode 3 can be increased, the antenna characteristics can be improved and the antenna gain can be increased.

In particular, in the first embodiment, the portion where the chip-shaped dielectric substrate 11 and the connection transmission line 12 are interposed is most susceptible to the dielectric loss tangent tan δ of the circuit board 2 and the antenna characteristics. Is located in the maximum current distribution region of the radiation electrode 3, which is largely involved in the radiation, and the portion of the radiation electrode 3 which is easily affected by the dielectric loss tangent tan δ of the circuit board 2 is separated from the circuit board 2; 11
By varying the dielectric constant and the dielectric loss tangent tan δ of the antenna, the antenna characteristics can be largely variably controlled, so that the antenna characteristics can be more reliably improved.

Hereinafter, a second embodiment will be described. A characteristic of the second embodiment is that a parasitic radiation electrode 16 is provided as shown in FIG. The other configuration is the same as that of the first embodiment. In the description of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the description of the common portions will be repeated. Is omitted. In FIG. 4, the components mounted on the circuit board 2 are not shown.

In the second embodiment, the parasitic radiation electrode 16 has a microstrip line shape.
The parasitic radiation electrode 16 is disposed in the non-ground area 4 of the circuit board 2 with one end thereof opposed to the open end 3a of the radiation electrode 3 with a space therebetween. Thereby, the radiation electrode 3
Is transmitted from the open end 3a of the radiation electrode 3 to the end of the parasitic radiation electrode 16 by magnetic field coupling.

For example, when an antenna capable of transmitting or receiving radio waves in two different frequency bands is required, the parasitic radiation electrode 16 is provided, for example, as shown in FIG.
As shown in (a), the electrical length and the like are designed and configured such that two different frequency bands are formed having a resonance frequency f2 different from the resonance frequency f1 of the radiation electrode 3.

When the frequency band of the radio wave of the antenna is required to be widened, for example, the parasitic radiation electrode 16 is set at the resonance frequency f1 of the radiation electrode 3 as shown in FIG. The parasitic radiation electrode 16 is designed and configured so as to have a nearby resonance frequency f2 and to have a multiple resonance state between the parasitic radiation electrode 16 and the radiation electrode 3.

According to the second embodiment, the same structure as that of the first embodiment is provided, so that the dielectric constant and the dielectric loss tangent tanδ of the circuit board 2 are similar to the first embodiment.
Thus, there is an effect that the antenna characteristics can be improved by compensating for the deterioration of the antenna characteristics caused by the above.

This has been confirmed by experiments performed by the present inventors. The experiment refers to the chip-shaped dielectric substrate 1
This is a measurement of how the antenna directivity on the ZX plane shown in FIG. 4 changes depending on the presence of the transmission line 1 and the connection transmission line 12. The experimental result is shown in FIG. The solid line α in FIG. 6 indicates that the radiation electrode 3 has a structure in which the chip-shaped dielectric substrate 11 and the connection transmission line 12 are interposed, as shown in the second embodiment. The dotted line β in FIG. 6 represents the antenna directivity.
Is that the radiation electrode 3 extends over the entire length of the circuit board 2 as in the prior art.
5 shows the antenna directivity when the antenna is directly formed. In the above experiment, the antenna directivity was measured with respect to radio waves having a frequency of 826 MHz.

As shown in FIG. 6, according to the results of the above experiment, the case where the chip-shaped dielectric substrate 11 and the connection transmission line 12 are interposed in the radiation electrode 3 as in the second embodiment is shown. , The maximum value is -2.7 (dBd) and the average value is -6.9 (dBd), whereas in the conventional configuration, the maximum value is -5.3 (dBd) and the average value is -5.3 (dBd). The value is -8.
8 (dBd). That is, in the antenna directivity on the ZX plane, the antenna gain is improved by about 3 (dBd) compared to the conventional antenna structure by having the unique antenna structure in the second embodiment. I understood that.

As shown in the above experimental results, in the second embodiment, similar to the first embodiment,
Since the connection electrode transmission line 12 formed on the chip-shaped dielectric substrate 11 is interposed in the radiation electrode 3, an effect that the antenna gain can be improved can be obtained.

In addition, in the second embodiment, since the parasitic radiation electrode 16 is provided in addition to the radiation electrode 3, a plurality of different parasitic characteristics can be obtained by appropriately setting the frequency characteristics of the parasitic radiation electrode 16. The transmission or reception of radio waves in this frequency band can be made possible, and the frequency band can be widened by making the radiation electrode 3 and the parasitic radiation electrode 16 in a multiple resonance state.

Hereinafter, a third embodiment will be described. The characteristic feature of the third embodiment is that, as shown in FIG. 7, the connection transmission line 12 is constituted by a conductor plate member 18, and the chip-shaped dielectric substrate 11 shown in each of the above-mentioned embodiments is provided with the same structure. Instead, air having a relative dielectric constant of 1 was disposed. Other configurations are the same as those of the above-described embodiments. In the description of the third embodiment, the same components as those of the above-described embodiments are denoted by the same reference numerals, and the description of the common portions will not be repeated. I do.

In the third embodiment, the connection transmission line 12 is constituted by a conductive plate member 18 bent in a substantially U-shape. The substantially U-shaped conductor plate member 1
8 are bent outwardly to connect to the radiation electrode 3 at the connection portions 21 (2 and 2).
1a, 21b).

Each connecting portion 21a, 2 of the conductor plate member 18
1b is a radiation electrode portion 10a at the end of the dividing portion 10 respectively.
Or, it is fixed to 10b using a connection means such as solder.
In the state where the conductor plate member 18 is connected to the radiation electrodes 10a and 10b and the radiation electrodes 10a and 10b at both ends of the dividing portion 10 are electrically connected by the conductor plate member 18 as described above, the conductor plate member 18 Connecting parts 21a, 21b
The other region has a form floating from the circuit board 2.

In the third embodiment, as in the above embodiments, the dividing portion 10 of the radiation electrode 3 is
The length of the radiation electrode 3 from the power supply end 3 b is provided at a portion that is about １ ／ or less of the entire length of the radiation electrode 3.

According to the third embodiment, the connection transmission line 12 is constituted by the conductor plate member 18 and air is disposed in place of the chip-shaped dielectric substrate 11.
That is, similar to the above embodiments, the radiation electrode 3
Since the connection transmission line 12 which is not affected by the dielectric constant and the dielectric loss tangent tan δ of the circuit board 2 is provided, the electrical characteristics of the connection transmission line 12 can be reduced without being affected by the circuit board 2. By performing variable control, antenna characteristics can be improved.

It should be noted that the present invention is not limited to the above embodiments, but can take various embodiments. For example, in the first and second embodiments, the connection transmission line 12 formed on the chip-shaped dielectric substrate 11 is linear, but the shape of the connection transmission line 12 is linear. It is not limited. For example, FIGS. 8A and 8B
As shown in the development view of each chip-shaped dielectric substrate 11, the connection transmission line 12 may have a meandering shape.
Further, as shown in an exploded view of the chip-shaped dielectric substrate 11 in FIG. 8C, a spiral connection transmission line 12 may be formed on the surface of the chip-shaped dielectric substrate 11. The width and pitch of the meandering or spiral connection transmission line 12 are set according to the required frequency characteristics, and are limited to the examples shown in FIGS. 8A to 8C. Not something.

As shown in FIGS. 8A to 8C, by forming the connection transmission line 12 in a meandering or spiral shape, the connection transmission line 12 can be lengthened. The size of the chip-shaped dielectric substrate 11 can be reduced.

Further, instead of forming the connection transmission line 12 on the surface of the chip-shaped dielectric substrate 11, the connection transmission line 12 may be formed inside the chip-shaped dielectric substrate 11. In this case, for example, the chip-shaped dielectric substrate 11
Is formed by a laminate of a plurality of sheet substrates, and a connection transmission line 12 is formed on the surface of the sheet substrate, which is inside the chip-shaped dielectric substrate 11.

Further, in each of the first and second embodiments, the chip-shaped dielectric substrate 11 has a rectangular parallelepiped shape. However, the shape of the chip-shaped dielectric substrate 11 is not limited to a rectangular parallelepiped shape. For example, the chip-shaped dielectric substrate 11 may have a triangular prism shape or a cylindrical shape.

Further, in each of the above embodiments, the dividing portion 10 of the radiation electrode 3 is provided at a position where the length from the feeding end 3b of the radiation electrode 3 is about 約 or less of the entire length of the radiation electrode 3. However, for example, when the maximum current distribution region of the radiation electrode 3 is different from the above-described region, the dividing portion 10 is configured such that the length from the feeding end 3b of the radiation electrode 3 is equal to the total length of the radiation electrode 3. It may be provided in a region other than the region of about 1/4 or less.
Further, if the dividing portion 10 cannot be interposed in the maximum current distribution region of the radiation electrode 3 due to the positional relationship of the components 6 mounted on the circuit board 2 or the like, the dividing portion 10 is 3 may be provided in an area other than the maximum current distribution area. In this case, although the degree of improvement in the antenna characteristics is lower than in the case where the dividing portion 10 is provided in the maximum current distribution region of the radiation electrode 3, the antenna characteristics can be improved as compared with the conventional configuration.

Furthermore, in each of the first and second embodiments, since the circuit board 2 is made of a dielectric material having a dielectric tangent tan δ larger than the dielectric tangent tan δ at which the antenna characteristics are good. , Chip-shaped dielectric substrate 1
1 is made of a dielectric material having a dielectric loss tangent tan δ smaller than that of the circuit board 2. For example, the dielectric tangent tan δ is smaller than the dielectric loss tangent tan δ at which antenna characteristics are improved.
When the circuit board 2 is made of a dielectric material having δ, the chip-shaped dielectric substrate 11 is made of a dielectric material having a dielectric loss tangent tanδ for compensating antenna characteristics larger than that of the circuit board 2. You may.

Further, in the third embodiment, the connection portions 21a and 21b are formed by bending the distal ends of the legs 20a and 20b of the substantially U-shaped conductor plate member 18 outward. And the foot portions 20a, 20 of the conductor plate member 18.
0b is bent inward to form connecting portions 21a, 21b.
b may be formed. Further, in the third embodiment, the conductor plate member 18 constituting the connection transmission line 12 has a substantially U shape, but the form of the conductor plate member 18 is not limited to the substantially U shape. .

Further, in each of the above embodiments, the radiation electrode 3 directly formed on the circuit board 2 is linear, but the radiation electrode 3 is partially or entirely formed in a linear shape such as a meander shape. Other shapes may be used. Also, as for the parasitic radiation electrode 16 as shown in the second embodiment, a part or the whole of the parasitic radiation electrode 16 may have a shape other than a linear shape such as a meander shape in the same manner as described above.

Further, when the parasitic radiation electrode 16 is provided as shown in the second embodiment, the parasitic radiation electrode 16 is also divided as shown in each of the above embodiments. A chip-shaped dielectric substrate 11 and a connecting transmission line 12 are provided in the dividing portion 10 or a connecting transmission line 12 made of a conductor plate member 18 is provided in the dividing portion 10. It is good also as a structure which performs.

[0058]

According to the present invention, since the connection electrode is provided with the connection transmission line formed on the chip-shaped dielectric substrate, the portion of the connection electrode in the radiation electrode is provided. Is formed apart from the circuit board and is not affected by the dielectric constant or the dielectric loss tangent tanδ of the circuit board.
By variably controlling the dielectric constant and the dielectric tangent tanδ of the chip-shaped dielectric substrate, the electrical characteristics of the connection transmission line can be changed, and the current distribution state of the radiation electrode can be variably controlled. ,
The antenna characteristics can be variably controlled.

From this, the dielectric material having the dielectric constant and the dielectric loss tangent tan δ for compensating the deterioration of the antenna characteristics due to the dielectric constant and the dielectric loss tangent tan δ of the circuit board can be obtained by:
The antenna characteristics can be improved by forming the chip-shaped dielectric substrate.

Therefore, an antenna structure having an excellent antenna gain can be easily obtained. In the wireless device having a unique antenna structure according to the present invention,
A wireless device with good antenna gain can be stably provided without being largely influenced by the dielectric constant and the dielectric loss tangent tanδ of the circuit board.

In the case where the chip-shaped dielectric base is made of a material having a dielectric loss tangent tan δ smaller than that of the circuit board, it is necessary to increase the current distribution in the radiating electrode at the portion where the connection transmission line is provided. Can be. Thereby, the antenna characteristics can be improved.

In the case where the parasitic radiation electrode is formed, the frequency characteristic of the parasitic radiation electrode is variably set so that the parasitic radiation electrode and the radiation electrode can
It is possible to provide an antenna capable of transmitting or receiving radio waves in a plurality of different frequency bands, or to create a multiple resonance state with a parasitic radiation electrode and a radiation electrode to widen the frequency band. You can do it.

The part where the length from the feeding end of the radiation electrode is about 1/4 or less of the entire length of the radiation electrode is the maximum area of the current distribution. By providing the radiating electrode at a position where the length from the feeding end is not more than about 1/4 of the total length of the radiating electrode, that is, at the portion of the circuit board which is easily affected by the dielectric loss tangent tanδ, Since the base and the transmission line for connection are provided, deterioration of antenna characteristics due to the dielectric constant and the dielectric loss tangent tanδ of the circuit board can be effectively suppressed, and the antenna characteristics can be improved.

In the case where the chip-shaped dielectric substrate is made of a dielectric material having a relative dielectric constant of 10 or less, the electrical length of the connection transmission line formed on the chip-shaped dielectric substrate is determined by the following formula. Since the length can be increased, the size of the chip-shaped dielectric substrate can be reduced.

The transmission line for connection is constituted by a conductor plate member, and even if air having a relative dielectric constant of 1 is arranged instead of the chip-shaped dielectric substrate,
The same excellent effects as described above can be obtained. Further, as compared with the case where the connection transmission line is formed on the chip-shaped dielectric substrate, the manufacturing process for forming the connection transmission line formed of the conductor plate member is simpler.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a characteristic antenna structure in a first embodiment.

FIG. 2 is a diagram for explaining characteristic portions in the antenna structure of the first embodiment.

FIG. 3 is a graph showing an example of a current distribution of a radiation electrode.

FIG. 4 is an explanatory diagram schematically showing a characteristic antenna structure in the second embodiment.

FIG. 5 is a graph showing an example of frequency characteristics of an antenna when a parasitic radiation electrode is provided.

FIG. 6 is a diagram illustrating antenna directivity as a result of an experiment performed by the present inventors.

FIG. 7 is a diagram for explaining a characteristic antenna structure in the third embodiment.

FIG. 8 is an explanatory diagram showing another example of a connection transmission line.

FIG. 9 is an explanatory diagram showing a conventional example of an antenna structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna structure 2 Circuit board 3 Radiation electrode 10 Dividing part 11 Chip-shaped dielectric substrate 12 Connection transmission line 16 Parasitic radiation electrode 18 Conductor plate member

Claims (7)

[Claims] An antenna structure in which a microstrip line-shaped radiating electrode is formed on a surface of a circuit board made of a dielectric material, wherein the radiating electrode is provided with a dividing portion formed of a gap. A chip-shaped dielectric substrate which is arranged so as to span the radiation electrodes at both ends of the divided portion; and a connection transmission line formed on the chip-shaped dielectric substrate and which electrically connects the radiation electrodes at both ends of the divided portion. An antenna structure characterized by having; 2. The antenna structure according to claim 1, wherein the chip-shaped dielectric base is made of a material having a dielectric loss tangent tan δ smaller than that of the circuit board. 3. One end of the radiation electrode forms a power supply end to which a signal is supplied, and the other end forms an open end. The radiation electrode is arranged at an interval from the open end of the radiation electrode. 3. The antenna structure according to claim 1, wherein a parasitic radiation electrode for magnetic field bonding with the radiation electrode is formed. 4. One end of the radiating electrode forms a feed end to which a signal is supplied, and the dividing portion of the radiating electrode has a length from the feeding end of the radiating electrode which is approximately equal to the total length of the radiating electrode. The antenna structure according to any one of claims 1 to 3, wherein the antenna structure is provided at a portion which is equal to or less than 1/4. 5. The antenna structure according to claim 1, wherein the chip-shaped dielectric substrate is made of a dielectric material having a relative dielectric constant of 10 or less. 6. A configuration in which air having a relative dielectric constant of 1 is disposed in the divided portion of the radiation electrode instead of the chip-shaped dielectric substrate, and the radiation electrode at both ends of the divided portion is electrically connected. The connection transmission line to be connected is formed of a conductor plate member, and the conductor plate member has a form in which a region other than a connection portion with the radiation electrode is floating from a circuit board. The antenna structure according to claim 1 or claim 3 or claim 4. 7. A wireless device comprising the antenna structure according to claim 1. Description: