JP2000278028A - Chip antenna, antenna system and radio unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized chip antenna where a resonance frequency can easily be adjusted and the frequency band can be made broad. SOLUTION: The chip antenna 10 is provided with a rectangular solid base 11, planar radiation conductors 12, 13 arranged on one major side of the base 11, a planar ground conductor 14 arranged to the other major side in the base 11 so as to oppose to the radiation conductors 12, 13, a feeding terminal 15 and a ground terminal 16 that are arranged from a side face of the base 11 to the other major side. Then the radiation conductor 12 acts like a 1st radiation conductor that is connected to the ground conductor 14 via a connection conductor 17, the feeding terminal 15 and a short-circuit conductor 18. Furthermore, the radiation conductor 13 acts like a 2nd radiation conductor that is connected only to the ground conductor 14 via the short-circuit conductor 18. As a result, the radiation conductor 12 that is the 1st radiation conductor forms a feeding element and the radiation conductor 13 that is the 2nd radiation conductor forms a non-feed element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a chip antenna,
Regarding the antenna device and the wireless device, particularly, a mobile phone,
The present invention relates to a chip antenna, an antenna device, and a wireless device that are small planar antennas suitable for use in wireless devices such as a GPS (Global Positioning System) receiver.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for miniaturization and weight reduction of radio equipment such as portable telephones and GPS receivers, and also miniaturization of components used in these radio equipment. Above all, the antenna is a relatively large component among the components, and therefore, the miniaturization is particularly required.

[0003] Under such circumstances, with the development of wireless devices, flat antennas represented by microstrip antennas and single-sided short-circuited microstrip antennas have been developed as small antennas. Among them, an inverted-F antenna 100 using a dielectric ceramic substrate as shown in FIG. 15 is known as an antenna that can be dramatically reduced in size. The inverted-F antenna 100 has a relative dielectric constant of 2 as a main component containing magnesium oxide, calcium oxide, and titanium oxide.
And a substrate 101 made of zero dielectric ceramic.
At this time, the shape of the inverted F antenna 100 is, for example, 13.
It is 0 mm x 13.0 mm in width x 6.0 mm in height. Then, a copper metal conductor film is applied to the upper and lower surfaces of the substrate 101, respectively, to form a radiation conductor 102 and a ground conductor 103, and a copper short-circuit between the radiation conductor 102 and the ground conductor 103 is formed on the side surface of the substrate 101. A short-circuit conductor 104 of a predetermined width made of a metal conductor film is deposited. In addition, this reverse F
In order to supply power to the antenna 100, the power supply conductor 1 is extended from a predetermined position of the radiation conductor 102 to the side surface of the substrate 101.
05 is provided. When such an inverted F antenna 100 is used, the ground conductor 103 on the lower surface of the substrate 101 is placed so as to be in contact with, for example, a metal chassis of a mobile phone, and used as a reception-only antenna. In this case, the inverse F
The antenna 101 operates as a microstrip-type inverted-F antenna. Note that such an inverted F antenna 101
, When the inductance component of the radiation conductor 102 is L and the capacitance component between the radiation conductor 102 and the ground conductor 103 is C, the resonance frequency f is f = 1 / (2π · (LC) ^1/2 ) Holds, for example, the inverted F antenna 100 (FIG. 15)
In this case, the resonance frequency is about 800 MHz.

[0004]

However, in the above-described conventional inverted-F antenna, if the resonance frequency is reduced so that it can be used up to the low frequency region, the capacitance component between the radiation conductor and the ground conductor increases. However, for that purpose, the distance between the radiation conductor and the ground conductor needs to be extremely narrow, and there is a problem that the precision of the production is required.

[0005] In addition, there is a problem in that the capacitance component between the radiation conductor and the ground conductor is limited due to the limitation of the manufacturing accuracy of the interval between the radiation conductor and the ground conductor, and the variable range of the resonance frequency is narrow.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a small chip antenna capable of easily adjusting the resonance frequency and widening the band.
An object is to provide an antenna device and a wireless device.

[0007]

In order to solve the above-mentioned problems, a chip antenna according to the present invention comprises a substrate having a plurality of laminated ceramic sheet layers, a plurality of radiation conductors provided on the substrate, A substantially flat ground conductor provided via the sheet layer so as to face the conductor,
A power supply terminal provided on the surface of the base, for supplying power to the radiation conductor, and a ground terminal provided on the surface of the base and connected to the ground conductor, wherein one of the radiation conductors is It is a first radiation conductor connected to the power supply terminal and the ground conductor, and the rest of the radiation conductor is a second radiation conductor connected only to the ground conductor.

[0008] Further, a substantially flat capacitor conductor provided via the sheet layer is provided so as to face at least one of the first and second radiation conductors.

An antenna device according to the present invention includes a base having a plurality of laminated ceramic layers, a radiating conductor provided on the base, and a radiating conductor provided on the base via the sheet layer so as to face the radiating conductor. A flat ground conductor, provided on the surface of the base, a power supply terminal for supplying power to the radiation conductor, and a ground terminal provided on the surface of the base and connected to the ground conductor; A first antenna element in which the radiating conductor is connected to the power supply terminal and the ground conductor, a base on which a plurality of sheet layers made of ceramics are stacked, a radiating conductor provided on the base; And a ground terminal provided on the surface of the base and connected to the ground conductor, the ground conductor being provided through the sheet layer. The second, which is only connected to the serial grounding conductor
Antenna element.

[0010] Further, a substantially flat capacitor conductor provided via the sheet layer is provided so as to face at least one of the radiation conductors of the first and second antenna elements.

[0011] A wireless device according to the present invention includes the above-described chip antenna.

Further, the present invention is characterized in that the antenna device described above is mounted.

According to the chip antenna of the present invention, since the first antenna includes the first radiation conductor connected to the power supply terminal and the ground conductor, and the second radiation conductor connected only to the ground conductor,
Leakage current generated from the first radiating conductor can flow through the second radiating conductor.

According to the antenna device of the present invention, the antenna device includes the first antenna element whose radiation conductor is connected to the power supply terminal and the ground conductor, and the second antenna element whose radiation conductor is connected only to the ground conductor. Therefore, the leakage current generated from the radiation conductor of the first antenna element can flow through the radiation conductor of the second antenna element.

According to the wireless device of the present invention, since a chip antenna or antenna device having a wide band is mounted, the band of the wireless device can be widened.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a first embodiment of a chip antenna according to the present invention. Chip antenna 1
Numeral 0 denotes a rectangular parallelepiped base 11, flat radiation conductors 12 and 13 provided on one main surface of the base 11, and radiation conductor 1
A flat ground conductor 14 provided on the other main surface side inside the base 11 so as to face the bases 2 and 13, a power supply terminal 15 and a ground terminal 16 provided from the side surface of the base 11 to the other main surface. Is provided.

The radiating conductor 12 becomes a first radiating conductor connected to the power supply terminal 15 via the connection conductor 17 and to the ground conductor 14 via the short-circuit conductor 18, respectively. Further, the radiation conductor 13 is connected to the ground conductor 1 via the short-circuit conductor 18.
4 becomes the second radiating conductor connected only. as a result,
The radiation conductor 12 as the first radiation conductor forms a feed element, and the radiation conductor 13 as the second radiation conductor forms a parasitic element.

FIG. 2 is an exploded perspective view of the base 11 constituting the chip antenna 10 of FIG. The base 11 is made up of rectangular sheet layers 111 to 11 made of a dielectric ceramic containing barium oxide, aluminum oxide and silica as main components.
3 are stacked. Of these, the plate-shaped radiation conductors 12 and 13 made of copper or a copper alloy and having a substantially rectangular shape are provided on the sheet layer 111 by screen printing, vapor deposition, or plating.

On almost the entire surface of the sheet layer 113,
A plate-like ground conductor 14 made of copper or copper alloy and having a substantially rectangular shape is provided by screen printing, vapor deposition, or plating, and a part of the ground conductor 14 is
The sheet layer 113 is drawn out to both ends on the long side.

Further, the radiation conductors 1 on the sheet layer 111 are provided at predetermined positions on the sheet layers 111 to 113 in the thickness direction.
Via hole VH11 connecting power supply terminal 2 (not shown) provided from the side surface of base 11 to the other main surface thereof
The via hole VH11 becomes a connection conductor 17 for connecting the radiation conductor 12 as the first radiation conductor and the power supply terminal 15 shown in FIG.

The radiation conductors 1 on the sheet layer 111 are provided at predetermined positions on the sheet layers 111 and 112 in the thickness direction.
A VH 12 is provided for connecting the ground conductors 14 on the sheet layer 113 with the ground conductors 2 and 13, and the via holes VH 12 are the radiation conductor 12 and the second radiation conductor which are the first radiation conductor shown in FIG. It becomes a short-circuit conductor 18 for connecting the radiation conductor 13 and the ground electrode 14.

Then, after laminating the sheet layers 111 to 113 and pressing them together, at about 800 to 1000 ° C. in a reducing atmosphere.
The base 11 provided with the radiation conductors 12 and 13, the ground conductor 14, the connection conductor 17, and the short-circuit conductor 18 on one main surface or inside thereof is formed at the above temperature.

FIG. 3 shows frequency characteristics of (a) reflection loss and (b) insertion loss of the chip antenna of FIG. In addition,
In FIG. 3, the solid line indicates the case of the chip antenna 10 (FIG. 1), and the broken line indicates the case of the chip antenna (not shown) having only the first radiation conductor as a comparative example.

From the reflection loss in FIG. 3A, the VSWR (Vo
The band width of the chip antenna 10 whose ltage Standing Wave Ratio (voltage standing wave ratio) is 3 or less is 2.00 GHz.
It can be seen that the resonance frequency is about 185 MHz, which is about 2.9 times wider than about 63 MHz (resonance frequency: 19.2 GHz) of the comparative example.

In addition, from the insertion loss in FIG. 3B, a notch (point A in FIG. 3B) where almost no radio wave is emitted occurs in a frequency region where the chip antenna 10 is out of the band. I understand.

FIG. 4 is a perspective view of a modification of the chip antenna 10 of FIG. The chip antenna 10a includes a rectangular parallelepiped base 11a, meandering radiating conductors 12a and 13a formed on one main surface of the base 11a, and the other inside the base 11 facing the radiating conductors 12a and 13a. It includes a flat ground conductor 14a provided on the main surface side, and a power supply terminal 15a and a ground terminal 16a provided from the side surface of the base 11a to the other main surface.

At this time, the radiation conductor 1 serving as the first radiation conductor
2a is a connecting conductor 17a provided inside the base 11a.
Are connected to the power supply terminal 15a and the ground conductor 14a via the short-circuit conductor 18a. The radiation conductor 13a serving as the second radiation conductor is connected only to the ground conductor 14a via the short-circuit conductor 18a provided inside the base 11a.

FIG. 5 is a perspective view of another modification of the chip antenna 10 of FIG. The chip antenna 10b
A rectangular parallelepiped base 11b, a meandering radiation conductor 12b and a flat radiation conductor 13b formed on one main surface of the base 11b, and the other inside the base 11b facing the radiation conductors 12b, 13b A flat ground conductor 14b provided on the main surface side, a power supply terminal 15b and a ground terminal 16 provided from the side surface of the base 11b to the other main surface.
b.

At this time, the radiation conductor 1 serving as the first radiation conductor
2b is a connecting conductor 17b provided inside the base 11b.
To the power supply terminal 15b and to the ground conductor 14b via the short-circuit conductor 18b. The radiation conductor 13b serving as the second radiation conductor is connected only to the ground conductor 14b via the short-circuit conductor 18b provided inside the base 11b.

FIG. 6 is a transparent perspective view of still another modification of the chip antenna 10 of FIG. Chip antenna 10
c denotes a rectangular parallelepiped base 11c, meandering radiation conductors 12c and 13c formed on one main surface of the base 11c so as to be close to each other, and a power supply provided from the side surface to the other main surface of the base 11c. Terminal 15c and grounding terminal 1
6c.

At this time, the radiation conductor 1 serving as the first radiation conductor
2c is a connecting conductor 17c provided inside the base 11c.
Are connected to the power supply terminal 15c and the ground conductor 14c via the short-circuit conductor 18c, respectively. The radiation conductor 13c serving as the second radiation conductor is connected only to the ground conductor 14c via the short-circuit conductor 18c provided inside the base 11c.

According to the above-described chip antenna of the first embodiment, the first radiation is connected to the power supply terminal via the connection conductor and the ground conductor via the short-circuit conductor on one main surface of the base. Since the second radiation conductor is provided with the conductor and the second radiation conductor connected only to the ground conductor via the short-circuit conductor, the leakage current generated from the first radiation conductor can flow through the second radiation conductor.

Therefore, the first radiation conductor and the second radiation conductor resonate at the same time due to the leakage current.
By simply feeding power to the first radiation conductor, the chip antenna has a plurality of resonance frequencies, and the chip antenna can be made smaller, have a wider band, and have lower power consumption.

Also, by adjusting the inductance component of the short-circuit conductor connecting the second radiation conductor and the ground conductor, the inductance component of the chip antenna can be adjusted without changing the resonance frequency of the chip antenna. . As a result, impedance matching between the chip antenna and the external circuit can be easily achieved.

In the modification of FIGS. 4 and 5, at least one of the radiation conductors is formed in a meander shape.
The bandwidth of the meandering radiation conductor can be increased. This is evident from the fact that the bandwidth is proportional to the capacitance between the radiating conductor and the ground conductor and inversely proportional to the radiating conductor inductance. Therefore, a wider band of the chip antenna can be realized.

Further, in the modification shown in FIG. 6, since the meandering radiating conductors are provided so as to be close to each other, the area for forming the radiating conductor is reduced, and the chip antenna can be made more compact.

FIG. 7 is a perspective view of a chip antenna according to a second embodiment of the present invention. Chip antenna 20
Is a rectangular parallelepiped base 21, plate-shaped radiation conductors 22 and 23 provided on one main surface of the base 21,
A flat ground conductor 24 provided on the other main surface side inside the base 21 so as to face the radiation conductors 2 and 23;
2 and 23, a flat capacitor conductor 2 provided between the radiation conductors 22 and 23 and the ground conductor 24.
5 and a power supply terminal 26 and a ground terminal 27 provided from the side surface of the base 21 to the other main surface.

Although not shown, the radiation conductors 22,
The capacitor 23 and the capacitor conductor 25 are provided to face each other via a sheet layer constituting the base 21.

The radiating conductor 22 becomes a first radiating conductor connected to the power supply terminal 26 via the connection conductor 28 and to the ground conductor 24 via the short-circuit conductor 29, respectively. Further, the radiation conductor 23 is connected to the ground conductor 2 via the short-circuit conductor 29.
4 becomes the second radiating conductor connected only. The capacitor conductor 25 is connected to the ground conductor 24 via the short-circuit conductor 29.
Connected to As a result, the radiation conductor 22 that is the first radiation conductor is a feed element, and the radiation conductor 23 that is the second radiation conductor is
Will form a parasitic element.

FIG. 8 is a perspective view of a modification of the chip antenna 20 of FIG. The chip antenna 20a includes a rectangular parallelepiped base 21a, plate-shaped radiation conductors 22a and 23a provided on one main surface of the base 21a, and a radiation conductor 22a.
a, a flat ground conductor 24a provided on the other main surface side inside the base 21a so as to face the radiation conductors 22a and 23a, and between the radiation conductor 22a and the ground conductor 24a so as to face the radiation conductors 22a and 23a. And a power supply terminal 26a and a ground terminal 27a provided from the side surface of the base 21a to the other main surface.

At this time, the radiation conductor 2 serving as the first radiation conductor
2a is a power supply terminal 26a via a capacitor conductor 25a and a connection conductor 28a provided inside the base 21a;
Each is connected to the ground conductor 24a via the short-circuit conductor 29a. Further, a radiation conductor 23a serving as a second radiation conductor
Is connected only to the ground conductor 24a via the short-circuit conductor 29a provided inside the base 21a.

The radiation conductor 22 serving as the first radiation conductor
a is connected to a power supply terminal 26a via a capacitor formed by a radiation conductor 22a and a capacitor conductor 25a and a connection conductor 28a, and is a voltage power supply type.

According to the above-described chip antenna of the second embodiment, since the capacitor conductor is provided so as to face the radiation conductor via the sheet layer constituting the base, the distance between the radiation conductor and the capacitor conductor, or By adjusting the area of the capacitor conductor, the capacitance component of the chip antenna can be easily adjusted. As a result, the resonance frequency of the chip antenna can be easily adjusted.

The distance between the radiation conductor and the capacitor conductor can be easily adjusted by changing the thickness of the sheet layer provided between the radiation conductor and the capacitor conductor.
Decisions can be made at the design stage. In addition, the area of the capacitor conductor can be determined at the design stage. Therefore, it is possible to determine the capacitance component of the chip antenna at a design stage that cannot be performed by the conventional inverted F antenna,
It is possible to prevent the resonance frequency of the chip antenna from deviating from the design value.

Further, since the capacitor conductor is flat, its area can be largely changed. Therefore, since the capacitance component of the chip antenna can be largely changed, the variable range of the resonance frequency of the chip antenna can be widened.

Further, in the modification of FIG. 8, the first radiation conductor is of a voltage supply type in which the first radiation conductor is connected to a power supply terminal via a capacitor formed by the first radiation conductor and the capacitor electrode and a connection conductor. Therefore, by adjusting the area of the capacitor conductor, the capacitance component of the capacitor formed by the first radiation conductor and the capacitor electrode can be adjusted.

As a result, since the capacitance component of the chip antenna can be adjusted without changing the resonance frequency of the chip antenna, impedance matching between the chip antenna and an external circuit can be easily achieved.

FIG. 9 is a perspective view of an embodiment of the antenna device according to the present invention. The antenna device 30 includes a first antenna element 31 and a second antenna element 32
And a mounting board 33 for mounting the first and second antenna elements 31 and 32.

FIG. 10 is a transparent perspective view of a first antenna element constituting the antenna device of FIG. The first antenna element 31 includes a rectangular parallelepiped base 33 and a flat radiation conductor 34 provided on one main surface of the base 33.
And a flat ground conductor 35 provided on the other main surface side inside the base 33 so as to face the radiation conductor 34, and a power supply terminal 36 and a ground terminal provided from the side surface of the base 33 to the other main surface. 37.

The radiation conductor 34 is connected to the power supply terminal 36 via the connection conductor 38 and to the ground conductor 35 via the short-circuit conductor 39, respectively. As a result, the first antenna element 31 becomes a feed element.

FIG. 11 is a transparent perspective view of a second antenna element constituting the antenna device of FIG. The second antenna element 32 includes a rectangular parallelepiped base 33 and a flat radiation conductor 34 provided on one main surface of the base 33.
And a flat ground conductor 35 provided on the other main surface inside the base 33 so as to face the radiation conductor 34, and a ground terminal 37 provided from the side surface of the base 33 to the other main surface.

The radiation conductor 34 is connected only to the ground conductor 35 via the short-circuit conductor 39. As a result, the second
Antenna element 32 is a parasitic element.

FIG. 12 is a perspective view of a modification of the first antenna element of FIG. The first feeding element
Antenna element 31a is a rectangular parallelepiped base 33a
A flat radiating conductor 34a provided on one main surface of the base 33a; a flat ground conductor 35a provided on the other main surface inside the base 33a so as to face the radiating conductor 34a; A flat plate-shaped capacitor conductor 40 provided between the radiation conductor 34a and the ground conductor 35a so as to face the conductor 34a, and a power supply terminal 36a and a ground terminal 3 provided from the side surface to the other main surface of the base 33a.
7a.

The radiation conductor 34a is connected to the connection conductor 38.
a and the ground conductor 35a via the short-circuit conductor 39a, respectively.
0 is connected to the ground conductor 35a via the short-circuit conductor 39a.

Although not shown, the radiation conductor 34a
The capacitor conductor 40 and the capacitor conductor 40 are provided to face each other via a sheet layer constituting the base 33a.

FIG. 13 is a perspective view of a modification of the second antenna element 32 of FIG. The second antenna element 32a, which is a parasitic element, includes a rectangular parallelepiped base 33a, a plate-shaped radiation conductor 34a provided on one main surface of the base 33a, and a base 33a so as to face the radiation conductor 34a. A flat ground conductor 35a provided on the other inside main surface side; a flat capacitor conductor 40 provided between the radiation conductor 34a and the ground conductor 35a so as to face the radiation conductor 34a; And a ground terminal 37a provided from the side surface to the other main surface.

The radiation conductor 34a is connected to the short-circuit conductor 39.
a, the capacitor conductor 40 is connected to the ground conductor 35a via the short-circuit conductor 39a.

Although not shown, the radiation conductor 34a
The capacitor conductor 40 and the capacitor conductor 40 are provided to face each other via a sheet layer constituting the base 33a.

According to the antenna device of the above-described embodiment, on the one main surface of the base, the first conductor having the power supply terminal via the connection conductor and the radiation conductor connected to the ground conductor via the short-circuit conductor, respectively. To include an antenna element and a second antenna element having a radiation conductor connected only to a ground conductor via a short-circuit conductor on one main surface of the base,
The leakage current generated from the first antenna element is
Of the antenna element.

Therefore, due to the leakage current, the first antenna element and the second antenna element
Since resonance occurs at the same time, the antenna device has a plurality of resonance frequencies only by feeding power to the first antenna element, so that a wider band and lower power consumption of the antenna device can be achieved.

Further, by adjusting the inductance component of the short-circuit conductor connecting the radiation conductor of the second antenna element and the ground conductor, the inductance component of the antenna device is adjusted without changing the resonance frequency of the antenna device. be able to. As a result, impedance matching between the antenna device and the external circuit can be easily achieved.

Further, the first antenna element and the second antenna element
By changing the arrangement angle between the first antenna element and the second antenna element, the degree of coupling between the first antenna element and the second antenna element can be changed. As a result, the bandwidth and the gain of the antenna device can be controlled. In addition, as the arrangement angle between the first antenna element and the second antenna element approaches 90 °, the frequency characteristics of the insertion loss of the chip antenna of FIG.
It is possible to suppress a notch having almost no emission of radio waves as seen in (b)).

In the modification shown in FIGS. 12 and 13, the capacitor conductor is provided on the first and second antenna elements so as to face the radiation conductor via the sheet layer constituting the base. By adjusting the distance between the capacitor antenna and the capacitor conductor or the area of the capacitor conductor, the capacitance components of the first and second antenna elements can be easily adjusted. As a result, the resonance frequency of the antenna device can be easily adjusted.

The distance between the radiation conductor and the capacitor conductor can be easily adjusted by changing the thickness of the sheet layer provided between the radiation conductor and the capacitor conductor.
Decisions can be made at the design stage. In addition, the area of the capacitor conductor can be determined at the design stage. Therefore, it is possible to determine the capacitance components of the first and second antenna elements at a design stage which cannot be performed by the conventional inverted F antenna, and it is possible to prevent the resonance frequency of the antenna device from deviating from the design value.

Further, since the capacitor conductor is flat, its area can be largely changed. Therefore, since the capacitance components of the first and second antenna elements can be largely changed, the variable range of the resonance frequency of the antenna device can be widened.

FIG. 14 shows the chip antenna 10 shown in FIG.
It is a wireless device equipped with. A wireless device, for example, a mobile phone terminal 50 has a circuit board 52 in which a chip antenna 10 is mounted on one main surface having a ground pattern 51 and arranged inside a housing 53.
Radio waves are transmitted and received from 0. The chip antenna 10 is electrically connected to the RF unit 54 of the mobile phone 50 disposed on one main surface of the circuit board 51 via a transmission line (not shown) on the circuit board 51 or the like. .

The chip antenna 10 shown in FIGS. 4 to 6, 7 and 8 is used instead of the chip antenna 10 shown in FIG.
0a to 10c, 20, and 20a may be mounted.

When the antenna device 30 shown in FIG. 9 is mounted, the first and second antenna elements 3
The mounting substrate 33 for mounting the first and second substrates 32 also serves as a circuit substrate on which the RF unit 44 of the mobile phone terminal 40 is disposed. A transmission line or the like that electrically connects the units is formed.

According to the above-mentioned portable telephone terminal, which is a wireless device, a small-sized and wide-band chip antenna and an antenna device are mounted, so that the portable telephone terminal can be reduced in size and bandwidth.

The first and second chip antennas described above
In the embodiment of the present invention and the embodiment of the antenna device, the case where the base is made of a dielectric ceramic mainly containing barium oxide, aluminum oxide, and silica has been described. However, the base is not limited to this dielectric ceramic. Instead, dielectric ceramics mainly composed of titanium oxide and neodymium oxide, magnetic ceramics mainly composed of nickel oxide, cobalt oxide and iron oxide, or a combination of dielectric ceramics and magnetic ceramics may be used.

The case where the radiating conductor is provided on one main surface of the base and the grounding conductor is provided inside the base has been described. However, both the radiating conductor and the grounding conductor are provided inside the base or the radiating conductor is provided. The same effect can be obtained even when the ground conductor is provided on the other main surface of the base inside the base.

Further, the case where the connection conductor and the grounding conductor are provided inside the base has been described. However, the same effect can be obtained when the connection conductor and the ground conductor are provided on the main surface or side surface of the base.

Also, the first and second chip antennas described above
In the embodiment, the case where two radiation conductors are provided and the second radiation conductor is provided has been described. However, three or more radiation conductors may be provided, and a plurality of second radiation conductors may be provided. In this case, the bandwidth can be increased according to the number of radiation conductors.

Further, in the above-described second embodiment of the chip antenna and the modified example of the antenna device, the case where the capacitor conductor is provided between the radiation conductor and the ground conductor has been described. Similar effects can be obtained even when provided between the ground conductors.

Although the case where the capacitor conductor is provided inside the base has been described, the same effect can be obtained when the capacitor conductor is provided on one main surface or the other main surface of the base. In particular, in this case, trimming of the capacitor conductor is facilitated, the area of the capacitor conductor can be more easily adjusted, and the resonance frequencies of the chip antenna and the antenna device can be more easily adjusted.

Further, in the above-described embodiment of the antenna device, the case where the number of the second antenna element is one has been described, but a plurality of the second antenna elements may be provided. In this case, the bandwidth can be increased according to the number of the first and second antenna elements.

[0077]

According to the chip antenna of the first aspect, the first radiation conductor connected to the base via the connection conductor, the first radiation conductor connected to the ground conductor via the short-circuit conductor, and the short-circuit conductor via the connection conductor. And the second radiating conductor connected only to the ground conductor, so that the leakage current generated from the first radiating conductor can flow through the second radiating conductor.

Therefore, the first radiation conductor and the second radiation conductor resonate at the same time due to the leakage current.
By simply feeding power to the first radiation conductor, the chip antenna has a plurality of resonance frequencies, and the chip antenna can be made smaller, have a wider band, and have lower power consumption.

Further, by adjusting the inductance component of the short-circuit conductor connecting the second radiation conductor and the ground conductor, the inductance component of the chip antenna can be adjusted without changing the resonance frequency of the chip antenna. . As a result, impedance matching between the chip antenna and the external circuit can be easily achieved.

According to the chip antenna of the second aspect, since the capacitor conductor is provided so as to face the radiation conductor via the sheet layer constituting the base, the space between the radiation conductor and the capacitor conductor or the area of the capacitor conductor is provided. , The capacitance component of the chip antenna can be easily adjusted. As a result, the resonance frequency of the chip antenna can be easily adjusted.

The distance between the radiation conductor and the capacitor conductor can be easily adjusted by changing the thickness of the sheet layer provided between the radiation conductor and the capacitor conductor.
Decisions can be made at the design stage. In addition, the area of the capacitor conductor can be determined at the design stage. Therefore, it is possible to determine the capacitance component of the chip antenna at a design stage that cannot be performed by the conventional inverted F antenna,
It is possible to prevent the resonance frequency of the chip antenna from deviating from the design value.

Further, since the capacitor conductor is flat, its area can be largely changed. Therefore, since the capacitance component of the chip antenna can be largely changed, the variable range of the resonance frequency of the chip antenna can be widened.

According to the antenna device of the third aspect, the first antenna element having the feeder terminal connected to the base via the connection conductor and the radiation conductor connected to the ground conductor via the short-circuit conductor, And a second antenna element having a radiation conductor connected only to the ground conductor via the short-circuit conductor, so that a leakage current generated from the first antenna element can flow to the second antenna element.

Therefore, due to the leakage current, the first antenna element and the second antenna element
Since resonance occurs at the same time, the antenna device has a plurality of resonance frequencies only by feeding power to the first antenna element, so that a wider band and lower power consumption of the antenna device can be achieved.

Further, by adjusting the inductance component of the short-circuit conductor that connects the radiation conductor of the second antenna element and the ground conductor, the inductance component of the antenna device is adjusted without changing the resonance frequency of the antenna device. be able to. As a result, impedance matching between the antenna device and the external circuit can be easily achieved.

Further, the first antenna element and the second antenna element
By changing the arrangement angle between the first antenna element and the second antenna element, the degree of coupling between the first antenna element and the second antenna element can be changed. As a result, the bandwidth and the gain of the antenna device can be controlled. In addition, as the arrangement angle between the first antenna element and the second antenna element approaches 90 °, it is possible to suppress a notch that emits almost no radio wave.

According to the antenna device of the fourth aspect, since the first and second antenna elements are provided with the capacitor conductor so as to face the radiation conductor via the sheet layer constituting the base, the radiation conductor and the capacitor are provided. Spacing with conductors,
Alternatively, by adjusting the area of the capacitor conductor,
The capacitance components of the first and second antenna elements can be easily adjusted. As a result, the resonance frequency of the antenna device can be easily adjusted.

The distance between the radiation conductor and the capacitor conductor can be easily adjusted by changing the thickness of the sheet layer provided between the radiation conductor and the capacitor conductor.
Decisions can be made at the design stage. In addition, the area of the capacitor conductor can be determined at the design stage. Therefore, it is possible to determine the capacitance components of the first and second antenna elements at a design stage which cannot be performed by the conventional inverted F antenna, and it is possible to prevent the resonance frequency of the antenna device from deviating from the design value.

Further, since the capacitor conductor is flat, its area can be largely changed. Therefore, since the capacitance components of the first and second antenna elements can be largely changed, the variable range of the resonance frequency of the antenna device can be widened.

According to the fifth aspect of the present invention, since a small-sized and wide-band chip antenna is mounted, it is possible to realize a small-sized and wide-band wireless device.

According to the sixth aspect of the present invention, since a small-sized and wide-band antenna device is mounted, it is possible to reduce the size and the bandwidth of the wireless device.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment of a chip antenna according to the present invention.

FIG. 2 is an exploded perspective view of the chip antenna of FIG.

3A and 3B are diagrams showing frequency characteristics of (a) reflection loss and (b) insertion loss of the chip antenna of FIG. 1;

FIG. 4 is a perspective view showing a modification of the chip antenna of FIG. 1;

FIG. 5 is a perspective view showing another modified example of the chip antenna of FIG. 1;

FIG. 6 is a perspective view showing still another modified example of the chip antenna of FIG. 1;

FIG. 7 is a perspective view of a chip antenna according to a second embodiment of the present invention.

FIG. 8 is a perspective view showing a modification of the chip antenna of FIG. 7;

FIG. 9 is a top view of one embodiment according to the antenna device of the present invention.

FIG. 10 is a perspective view of a first antenna element included in the antenna device of FIG. 9;

11 is a perspective view of a second antenna element included in the antenna device of FIG. 9;

FIG. 12 is a perspective view showing a modification of the first antenna element of FIG. 10;

FIG. 13 is a perspective view showing a modification of the second antenna element of FIG. 11;

FIG. 14 is a perspective side view of a mobile phone equipped with the chip antenna shown in FIG. 1;

FIG. 15 is a perspective view showing a conventional chip antenna.

[Explanation of symbols]

10, 10a to 10c, 20, 20a Chip antenna 11, 11a to 11c, 21, 21a, 33, 33a
Substrates 111 to 113 Sheet layers 12, 12a to 12c, 22, 22a First radiating conductors 13, 13a to 13c, 23, 23a Second radiating conductors 14, 14a to 14c, 24, 24a Ground conductors 15, 15a to 15c , 26,26a, 36,36a
Power supply terminals 16, 16a to 16c, 27, 27a, 37, 37a
Grounding terminal 25, 25a, 40 Capacitor conductor 31, 31a First antenna element 32, 32a Second antenna element 34, 34a Radiating conductor 50 Cellular phone terminal (wireless device)

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4E351 AA07 AA11 BB03 BB09 BB17 BB22 BB30 BB31 BB32 BB49 CC03 CC06 CC11 DD04 DD21 EE01 GG07 5J045 AA01 AA02 AA04 AB05 AB06 DA10 EA07 GA01 HA03 LA01 MA07 NA07 A07 A13 AAB AB07

Claims (6)

[Claims] 1. A base in which a plurality of sheet layers made of ceramics are laminated, a plurality of radiation conductors provided on the base, and a substantially flat plate provided through the sheet layer so as to face the radiation conductor. A radiating conductor, comprising: a grounding conductor; a power supply terminal provided on the surface of the base for supplying power to the radiation conductor; and a grounding terminal provided on the surface of the base and connected to the grounding conductor. Is a first radiation conductor connected to the power supply terminal and the ground conductor, and the rest of the radiation conductor is a second radiation conductor connected only to the ground conductor. Chip antenna. 2. The device according to claim 1, further comprising a substantially flat capacitor conductor provided via the sheet layer so as to face at least one of the first and second radiation conductors. Chip antenna. 3. A base in which a plurality of sheet layers made of ceramics are laminated, a radiating conductor provided on the base, and a substantially flat ground conductor provided via the sheet layer so as to face the radiating conductor. A power supply terminal provided on the surface of the base, for supplying power to the radiation conductor, and a ground terminal provided on the surface of the base and connected to the ground conductor, wherein the radiation conductor is A first antenna element connected to a power supply terminal and the ground conductor;
A base in which a plurality of ceramic sheet layers are stacked, a radiating conductor provided on the base, a substantially flat ground conductor provided via the sheet layer so as to face the radiating conductor, and An antenna device, comprising: a ground terminal provided on a surface and connected to the ground conductor; and a second antenna element having the radiation conductor connected only to the ground conductor. 4. A substantially flat capacitor conductor provided through the sheet layer so as to face at least one of the radiation conductors of the first and second antenna elements. 4. The antenna device according to 3. 5. A wireless device equipped with the chip antenna according to claim 1 or 2. 6. A wireless device having the antenna device according to claim 3 mounted thereon.