JP2002141733A - Antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna that can increase the inductance of a coil section consisting of conductors formed on a board as designed. SOLUTION: The antenna A provided with each of resonance sections E1, E2 where an inductance section 1 having the coil section 1a and a capacitance section 2 are connected electrically in parallel is configured such that the coil section 1a is formed with conductor patterns 11, 11, etc., formed on a side K1a of a board K1, conductor patterns 12, 12, etc., formed on a side K2b of a board K2, and coil conductor section 13, 13, etc., electrically interconnecting them, and intermediate boards K3, K3, etc., formed with the coil conductor sections 13, 13, etc., are provided between the boards K1 and K2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna which can be used particularly suitably as a small antenna incorporated in various devices having a function of transmitting and receiving radio waves, including various communication devices for transmitting and receiving radio waves.

[0002]

2. Description of the Related Art In recent years, with the growing demand for various devices having a function of transmitting and receiving radio waves, including various communication devices for transmitting and receiving radio waves, antennas used in a frequency band of several hundred MHz to several tens of GHz are increasing. It is being used. Needless to say, it is often used for non-contact cards used for mobile communication, next-generation transportation systems, automatic ticket inspections, etc. Also, wireless use of cordless Internet home appliances, in-house wireless LAN, Bluetooth
For example, a method of exchanging data wirelessly without using a long and complicated cable such as "oth" is being used, and a wide range of applications is expected in this area. It is also used to transmit and receive data wirelessly from various terminals.
Demand is also increasing for the spread of telemetering for exchanging gas and other information required for safety management by radio waves, POS systems for financial terminals, and the like. In addition, the range of use has become extremely wide, such as home electric appliances such as televisions for portable satellite broadcasting receivers and applications to vending machines. Until now, the mainstream antenna used for various devices having the function of transmitting and receiving radio waves as described above has been a stretchable monopole antenna attached to a case of the device. Also, a helical antenna projecting short outside the case is known.

[0003] However, the monopole antenna has a drawback that the operation is troublesome because it needs to be extended for each use, and furthermore, the extended antenna portion is easily broken. Also, in the case of a helical antenna, since the antenna body consisting of an air core coil is protected by a cover material such as resin, the external shape tends to be large, and if it is fixed outside the case, the problem that the overall appearance is not good is avoided. I couldn't. However, simply reducing the size of the antenna reduces the gain at the same time,
There has been a problem that the circuit of the radio wave transmission / reception system has to be large, the power consumption has to be remarkable, and the battery has to be large, so that the whole device cannot be downsized.

[0004] In view of this, attempts have been made to implement a small and high-gain antenna in a circuit configuration by forming a resonance unit for transmitting and receiving radio waves by a resonance circuit including an inductance component and a capacitance component. In this case, a high gain cannot be obtained only by providing one resonating unit, and therefore, it is necessary to combine a plurality of resonating units to constitute one antenna as a whole. FIG. 4 shows an antenna having such a configuration as an equivalent circuit. In the figure, the antenna C includes two resonating portions E10 and E20, and the resonating portions E10 and E20 are electrically connected in series. Each of the resonance units E10 and E20 includes an inductance unit 100 and a capacitance unit 200 connected in parallel. One end of the resonance unit E10 is connected to the resonance unit E
10, E20 are connected to a power supply port 300 for supplying power. An impedance matching unit 400 having an inductance component and a capacitance component and matching the input impedance of the antenna C is externally connected to the power supply port 300. Further, an antenna C is provided at one end of the resonance section E20.
A frequency adjustment capacitance section 500 for adjusting the entire resonance frequency is connected in series.

FIG. 5 is a perspective view showing an antenna C having a conventional configuration. In the figure, the inductance units 100 and 100 of the antenna C are respectively
a, 100a. Coil units 100a, 100
a are formed in the conductor patterns 110, 110... and the conductor patterns 120, 120. Including coil conductors 130, 130... Made of a conductor such as a filled metal or a conductive resin;
These are electrically connected to each other so as to be wound in a square shape that can be approximated to a spiral around the axis N. Note that the coil unit 100 for determining the inductance value
a, 100a is given by the product of the length of substantially the conductor pattern 110 or the conductor pattern 120 and the length of the coil conductor 130, and therefore the thickness d and width W of the substrate M. Approximately depends on the dimensions of Further, as shown in FIG. 6, the conductor patterns 110, 110... Of the resonance part E10 and the conductor patterns 110, 110.
20 to reduce the mutual interference between
They are formed at different angles with respect to the axis N.

[0006]

In the conventional antenna having the above-described structure, when the area of the board on which the antenna is mounted is not so limited, the thickness and width of the board are increased to obtain an inductance value. Can be increased as needed. However, for example,
A substrate obtained by firing a flexible green sheet mainly composed of a ceramic material has too large dimensions such as thickness and width. There was a problem that the displacement occurred.

When the center frequency to be used is high, if the conductor patterns are formed to be long in parallel and close to each other, a short circuit occurs between the conductor patterns and the meaning of the pitch is lost. Since the wavelength of radio waves is proportional to the reciprocal of the square root of the dielectric constant,
In a substrate made of a material having a higher dielectric constant than in the air, the wavelength of a radio wave is shortened, and the interval between conductor patterns can be narrowed accordingly. For this reason, burying the conductor pattern inside the substrate as a through hole can prevent the short circuit between the conductor patterns and form the conductor patterns close to each other, rather than forming the conductor pattern exposed outside the substrate, This is effective in reducing the size of the entire antenna. However, there is a problem that it is impossible to form a long through hole in a thin substrate along the direction in which the substrate extends.

[0008] Mutual interference between adjacent resonating parts is such that at least one of the portions that make a round around the axis of the coil part is substantially included in a plane inclined with respect to the axis, and the inclined plane is the coil of the adjacent resonating part. If the sections have different slopes, mutual interference is reduced. In order to achieve such a configuration, for example, as described above, the conductor pattern on the substrate surface must be formed so as to have a different angle with respect to the axis in the adjacent resonance portions. This is because a through hole can be formed only in a direction perpendicular to the substrate, and it is impossible to form the through hole obliquely with respect to the axis. In order to provide a fixed opening area to the coil portion, the conductor pattern must be formed to extend long on the substrate surface. This is because the thickness of the substrate has a limitation in the manufacturing method, and the length of the coil conductor cannot be increased beyond the thickness of the substrate.
As described above, as a result of the conductor pattern extending long on the substrate surface and being formed with different inclinations in the coil portions of the adjacent resonance portions, for example, as shown in FIG. The surface on which is formed is also wide, and a useless space in which a conductor pattern consisting of only the substrate is not formed is generated between the resonance portions. Thus, in order to increase the gain of the antenna, a plurality of resonating parts are connected,
If the configuration is such that mutual interference between adjacent resonance units is reduced, there is a problem that a wasteful space is generated between the resonance units and the size of the antenna is increased.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an antenna capable of increasing an inductance value of a coil portion made of a conductor formed on a substrate as designed. Another object of the present invention is to provide an antenna capable of reducing the distance between conductors of a coil portion even at a high frequency. Another object of the present invention is to provide an antenna capable of reducing the size of the antenna by reducing useless portions where the conductor pattern only on the substrate is not formed while reducing mutual interference between adjacent resonance portions. .

[0010]

According to a first aspect of the present invention, there is provided a resonating section in which an inductance section having a coil section and a capacitance section are electrically connected in parallel, wherein the coil section has A first conductor pattern formed on one surface, a second conductor pattern formed on a second surface, and an electrical connection between the first conductor pattern and the second conductor pattern An antenna formed in a shape that can be approximated to a spiral by a coil conductor portion to be formed, wherein the first surface is a surface of a first substrate, and the second surface is a surface of a second substrate. At least one intermediate substrate is provided between the first substrate and the second substrate, and the coil conductor portion is formed on the intermediate substrate. .

With such a configuration, the first conductor pattern and the second conductor pattern are formed on different substrates, and the first substrate and the second substrate on which the first conductor pattern is formed are formed. An intermediate substrate on which a coil conductor portion is formed is inserted between the second substrate on which the conductor pattern is formed, and the first conductor pattern and the second conductor pattern are interposed between the second substrate and the second substrate. Separated. Thus, the opening area of the coil portion can be increased by the intermediate substrate. Further, since it is not necessary to increase the dimensions of the substrate, it is possible to reduce errors that occur in manufacturing and increase the inductance value as designed.

According to a second aspect of the present invention, there is provided the antenna according to the first aspect, wherein a plurality of the intermediate substrates are provided.

With such a configuration, the distance between the first conductor pattern and the second conductor pattern can be changed according to the number of intermediate substrates inserted therebetween. Thus, the opening area of the coil portion can be increased by increasing the number of intermediate substrates, and the inductance value can also be increased. At this time, the first substrate, the second substrate, and the intermediate substrate can all be selected to have dimensions that do not increase the errors that occur in manufacturing, so that an inductance value as designed can be obtained.

According to a third aspect of the present invention, in the antenna according to the first or second aspect, the coil conductor portion includes a through hole penetrating the intermediate substrate. I do.

With this configuration, the space between adjacent coil conductors is filled with a substance having a higher dielectric constant than the dielectric constant of vacuum, and the wavelength of the radio wave between the coil conductors is shortened. The distance between the parts can be reduced, and the size of the antenna can be reduced.

According to a fourth aspect of the present invention, there is provided the antenna according to any one of the first to third aspects, wherein the antenna has a plurality of the resonating portions, and the resonating portions are electrically connected in series. The coil portions of the adjacent resonance portions are arranged such that the axes of the spirals are aligned on substantially the same straight line, and at least one of the portions that circles the axis is the first substrate, the intermediate substrate, and the second Parallel to the direction in which the substrates are arranged, and is substantially included in a plane inclined with respect to the axis, wherein the inclined plane has a different inclination in the adjacent coil portion. I do.

With such a configuration, it is possible to effectively increase the antenna gain by suppressing mutual interference between the resonating portions.

According to a fifth aspect of the present invention, there is provided the antenna according to the fourth aspect, wherein the coil portion has a reduced conductor pattern while keeping an opening area of the coil portion constant, and The conductor is extended so that the length of the conductor pattern is shorter than the length of the coil conductor, and the first substrate, the second substrate, and the intermediate substrate are formed by a length of the conductor pattern. The first surface and the second surface are provided in a reduced size as the size is reduced, and overlap each other when viewed from the direction in which the first substrate, the intermediate substrate, and the second substrate are arranged. It is characterized by being provided.

In the present invention, the coil portion is formed such that the length of the coil conductor portion is longer than the length of the conductor pattern, and the first substrate, the second substrate, and the intermediate substrate are reduced in accordance with the conductor pattern. Provided. The opening area of the coil portion is determined substantially by the product of the length of the coil conductor portion and the length of the conductor pattern, but the coil portion is formed such that the length of the conductor pattern inclined with respect to the axis is shorter than the coil conductor portion. If the length of the coil conductor portion is adjusted by the intermediate substrate, the surface of the substrate required for forming the conductor pattern is reduced, and only the substrate where the conductor pattern is not formed between the resonance portions is wasted. No space is generated, and the size of the antenna can be reduced.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an antenna according to the present invention will be described with reference to the drawings.

1 to 3 show an embodiment of the antenna according to the present invention. In the figure, the antenna A includes two resonating portions E1 and E2, and the resonating portions E1 and E2 are electrically connected in series. Resonance parts E1, E2
Are formed by connecting an inductance unit 1 and a capacitance unit 2 in parallel. One end of the resonance unit E1 is connected to a power supply port 3 that supplies power to the resonance units E1 and E2. Further, one end of the resonance section E2 has a frequency adjustment capacitance section 5 for adjusting the resonance frequency of the entire antenna A.
Are connected in series.

The inductance units 1 and 1 have coil units 1a and 1a, respectively. The coil parts 1a, 1a
The conductor patterns 11, 11,... Formed on the surface K1a (first surface) orthogonal to the thickness direction of the thin rectangular substrate K1 (first substrate) and the thin rectangular substrate K
Are formed on a surface K2b (second surface) orthogonal to the thickness direction of the second substrate (second substrate), and the conductive patterns 11, 11,. ...
Are electrically connected to each other, and are formed so as to be wound in a rectangular spiral around the axis L. Here, a plurality of thin rectangular intermediate substrates K3, K3,... Are laminated in the thickness direction between the substrates K1 and K2. Are formed in the through holes penetrating through the substrates K3, K3,... And made of a conductor such as a metal or a conductive resin.
Also, the conductor patterns 11, 11,...
The lengths of the coil conductors 13, 13,... Are longer than the lengths of 2, 12,.

Further, as shown in FIG. 3, the conductor patterns 11, 11,... Of the resonance section E1 and the conductor patterns 11, 11,. In order to reduce mutual interference between them, they are formed at different angles with respect to the axis L when viewed from above. That is, the portions of the coil portion 1a that make a round around the axis L are
, K2, and the intermediate substrates K3, K3,... Are parallel to the direction in which the intermediate substrates K3, K3,. H, H
Have different inclinations in the adjacent coil portions 1a, 1a.

The capacitance units 2, 2 have capacitor units 2a, 2a. Condenser parts 2a, 2a
. Are formed on one surface of the substrates K4, K4, K4, respectively, and the conductor patterns 22a, 22a respectively formed on the other surfaces of the substrates K4, K4, K4. .. And the conductor patterns 22a, 2a.
Are arranged so as to face each other. Then, one of the conductor patterns 21a, 21a of the resonance portion E1
.. Are connected to the power supply port 3 and the other conductor patterns 22a, 22a,.
Are electrically connected to connection points between the coil portions 1a, 1a, respectively. Are electrically connected to connection points between the coil portions 1a, 1a, and the other conductor patterns 22a, 22a... Are electrically connected to the frequency adjustment capacitance portion 5, respectively. It is connected. Here, the condenser parts 2a, 2a
In order to reduce the area of the conductor pattern 4, the substrate K4 is further laminated, and the conductor patterns 21a and 22
It is configured such that the value of the capacitance can be increased by forming a so as to oppose a.

In the antenna A shown in FIGS.
The conductor patterns 11, 11,... And the conductor patterns 12, 12,.
Are separated from each other by intermediate substrates K3, K3,. Thus, the opening area O of the coil portion 1a is
Can be increased by the intermediate substrates K3, K3,. Since the dimensions of the substrate K1, the substrate K2, and the intermediate substrate K3 are constant, and errors that occur in their manufacture are well known, the inductance value can be increased as designed. Further, the opening area O and the inductance value of the coil portion 1a are arbitrarily adjusted by changing the number of the intermediate substrates K3.

The adjacent coil conductors 13, 13,...
Are filled with a substance having a higher dielectric constant than the vacuum dielectric constant forming the substrate K3, and the coil conductors 13, 13,.
, The wavelength of the radio wave becomes short, the influence of the high frequency can be suppressed, the interval between the coil conductors 13, 13,... Can be narrowed, and the size of the antenna A can be reduced.

Further, mutual interference between the resonance portions E1 and E2 is suppressed, and the gain of the antenna A is effectively increased. The opening area O of the coil part 1a is substantially equal to the coil conductor parts 13,13.
.. And the length of the conductor patterns 11, 11,... Or the conductor patterns 12, 12,. .. And the conductor patterns 12, 12,... Are shorter than the coil conductors 13, 13,. , 11... And conductor patterns 12, 12,.
..Width U and length V of substrates K1 and K2 required for formation
Is reduced, so that there is no wasteful space between the resonance portions E1 and E2 where no conductor pattern consisting of only the substrate is formed.

As described above, according to the present embodiment, the opening area O of the coil portion 1a can be increased by the intermediate substrates K3, K3,.
The inductance value can be increased as designed. The value can be adjusted by the number of the intermediate substrates K3. The adjacent coil conductors 1a, 1
a can be reduced, and the size of the antenna A can be reduced. Further, no useless space is generated between the resonance portions E1 and E2, and the size of the antenna A can be reduced.

In the above embodiment, the coil section 1a
Are formed from a material having a higher dielectric constant than the vacuum dielectric constant, but may be formed from a material having a high magnetic permeability such as ferrite. In a high frequency band whose frequency is several tens of MHz or more, the loss is certainly large, but if it is used in a frequency band of several hundred kHz to several MHz, such as for AM reception of radio, it is necessary to increase the inductance value. It is effective. Further, a structure in which a dielectric material such as alumina or titanium oxide is used for the substrate on which the capacitance portion 2 is formed, and a magnetic material such as ferrite is used for the substrate on which the inductance portion 1 is formed may be used.

[0030]

The present invention has the following effects. According to the first aspect of the invention, the coil portion of the resonance section is formed on the first conductor pattern formed on the first surface of the first substrate and on the second surface of the second substrate. Formed between the second conductor pattern and a coil conductor portion for electrically connecting them, and an intermediate substrate having the coil conductor portion formed between the first substrate and the second substrate. Since at least one is provided, the opening area of the coil portion can be increased by the intermediate substrate, and the inductance value can be increased as designed.

According to the second aspect of the present invention, since a plurality of intermediate substrates are provided, the opening area of the coil portion is
By increasing the number of intermediate substrates, it can be increased,
The inductance value can also be increased. At this time,
The first substrate, the second substrate, and the intermediate substrate can each be selected to have dimensions that do not increase the errors that occur in manufacturing, so that an inductance value as designed can be obtained.

According to the third aspect of the present invention, since the coil conductor is formed of a through hole penetrating the intermediate substrate, the interval between adjacent coil conductors can be reduced, and the size of the antenna can be reduced. Can be miniaturized.

According to the fourth aspect of the present invention, the plurality of resonating portions are electrically connected in series, and the coil portions of the adjacent resonating portions have their spiral axes aligned substantially on the same straight line,
At least one of the portions that circle the axis is parallel to the direction in which the first substrate, the intermediate substrate, and the second substrate are arranged, and is substantially included in a plane inclined with respect to the axis, and the inclined plane Since the adjacent coil sections have different inclinations, it is possible to effectively increase the antenna gain by suppressing mutual interference between the resonance sections.

According to the fifth aspect of the present invention, in the coil portion, the conductor pattern is reduced while keeping the opening area constant, and the length of the conductor pattern is increased by extending the coil conductor portion. The first substrate, the second substrate, and the intermediate substrate are formed so as to be shorter than the length of the portion, and the first surface and the second surface are provided with the reduced length of the conductor pattern and Since the first substrate, the intermediate substrate, and the second substrate are provided so as to overlap with each other when viewed from the direction in which the first substrate, the intermediate substrate, and the second substrate are arranged, wasteful space of only the substrate on which the conductor pattern is not formed between the resonance portions occurs. The size of the antenna can be reduced.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of the present invention, and is a perspective view showing an example of an antenna.

FIG. 2 is a front view of FIG.

FIG. 3 is a top view of FIG. 1, showing an arrangement of conductive patterns.

FIG. 4 is a diagram showing an equivalent circuit of the antenna.

FIG. 5 is a perspective view showing an example of a conventional antenna.

FIG. 6 is a top view of FIG. 5, showing an arrangement of conductor patterns.

[Explanation of symbols]

 A: antenna H: plane K1: substrate (first substrate) K1a: surface (first surface) K2: substrate (second substrate) K2b: surface (first L: Axis line O: Opening area E1, E2: Resonant part 1 ... Inductance part 2 ... Capacitance part 1a ... Coil part 11 ... Conductor pattern 12 ...・ Conductor pattern 13 ・ ・ ・ Coil conductor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01Q 21/28 H01Q 21/28 (72) Inventor Toshiyuki Chiba 5-1-1 Otemachi 1-chome, Chiyoda-ku, Tokyo Mobile Business Promotion Division, Mitsubishi Materials Corporation (72) Inventor Shiro Shigimura 1414 Uchigicho, Kanazawa-shi, Ishikawa Pref. Address FFC Co., Ltd. F-term (reference) 5J021 AA02 AB04 GA08 HA05 HA10 JA02 5J046 AA04 AA07 AB11 PA06 QA02

Claims (5)

[Claims] An inductance part having a coil part;
A resonance section formed by electrically connecting a capacitance section to the coil section, wherein the coil section has a first conductor pattern formed on a first surface and a second conductor formed on a second surface. Patterns and
An antenna formed in a shape that can be approximated to a spiral by a coil conductor that electrically connects the first conductor pattern and the second conductor pattern, wherein the first surface is The surface of the first substrate, the second surface is the surface of the second substrate, between the first substrate and the second substrate, at least one intermediate substrate is provided An antenna, wherein the coil conductor is formed on the intermediate substrate. 2. The antenna according to claim 1, comprising a plurality of said intermediate substrates. 3. The antenna according to claim 1, wherein the coil conductor comprises a through hole penetrating the intermediate substrate. 4. The antenna according to claim 1, further comprising: a plurality of said resonating portions, wherein said resonating portions are electrically connected in series, and said plurality of resonating portions are adjacent to one another. In the coil portion, the axis of the helix is aligned on substantially the same straight line, and at least one of the portions that circle the axis is in a direction in which the first substrate, the intermediate substrate, and the second substrate are arranged. parallel,
The antenna is substantially included in a plane inclined with respect to the axis, and the inclined plane has different inclinations in the adjacent coil units. 5. The antenna according to claim 4, wherein, in the coil portion, the conductor pattern is reduced while the opening area of the coil portion is kept constant, and the coil conductor portion is extended. The length of the conductor pattern is formed to be shorter than the length of the coil conductor portion, and the first substrate, the second substrate, and the intermediate substrate are connected to the first substrate together with a reduction in the length of the conductor pattern. And the second surface are provided in a reduced size, and are provided so as to overlap each other when viewed from a direction in which the first substrate, the intermediate substrate, and the second substrate are arranged. And antenna.