JP2001203519A - Antenna system for transmission reception module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized antenna system compatible with a short distance wireless communication with a stable characteristic and to provide a transmission reception module mounted with a transmission reception circuit. SOLUTION: Conductor layer patterns 5, 6 of a pair configuration being an antenna of a dipole configuration are provided in a module board 11 consisting of dielectric boards 7, 8, 9, 10 with a high specific dielectric constant, placed closely to each other along two sides 12, 13 of the board 11 of a rectangular shape, a plurality of electric components 15 for an RF transceiver is provided to the inside of the module board 11 to configure the module for the short distance wireless communication mounted with a large scale integrated circuit 14 incorporating a base band processing circuit or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna used for a short-range wireless device, and more particularly to an antenna device of a transmitting / receiving module which is modularized with a large-scale integrated circuit.

[0002]

2. Description of the Related Art In general, antennas used in conventional portable radio equipment include a whip antenna and a helical antenna projecting out of a housing, and an inverted F-type antenna and a chip antenna incorporated therein.

As shown in FIG. 6, (COMDEX / Fal
(Digitalswer A / S exhibition at 1'99, or described in Nikkei Electronics No. 12-13, 1999), an antenna device of a transmitting / receiving module in which an inverted F-shaped antenna or an L-shaped antenna is formed on a resin substrate 1 by a conductor layer pattern 2 There is. Since the ground base plate 3 is required, there is a limit to downsizing, and the characteristics become unstable when the ground base plate has a small area.

[0004] When used in portable radio equipment, the above-mentioned conventional antenna has a large change in gain, directivity and fractional bandwidth depending on whether or not a human body approaches. The smaller the helical antenna or the chip antenna, the lower the gain and the smaller the specific bandwidth. Further, the width of the directional characteristics is insufficient for use in portable wireless devices or the like limited to transmission and reception within a certain distance.

Further, when a transmitting / receiving module is built in, such as a portable notebook personal computer or a digital still camera, an antenna that can be used in a metal housing without protruding is required, but the conventional antenna cannot cope with it.

[0006]

There is a need for a small and thin module that integrates a transmitting and receiving circuit and an antenna that can be used in portable radio equipment. In addition, the gain is high, the relative bandwidth and the directional characteristics are wide, the influence of the proximity of the human body is small, and a metal housing can be built in and used.

[0007]

According to the present invention, there is provided an antenna apparatus for a transmission / reception module in which a dipole antenna is formed by a pair of conductor wires having a feed end at the center for stable antenna characteristics. Since the lines are mainly arranged between a plurality of dielectric plates having a large relative permittivity constituting the module substrate, the lines are formed by a conductor layer pattern.

For the purpose of shortening the antenna length, the conductor layer pattern of a pair of conductor wires can be arranged on a plurality of dielectric plates, but is arranged between a plurality of dielectrics having a large relative permittivity. I do. When a dielectric plate having a relative dielectric constant of 8.0 or more is used, the effect of shortening is large.

For the purpose of widening the directional characteristics of the antenna and reducing the size of the module substrate, the conductor layer pattern of the paired conductor wires is placed at a position between the large-scale integrated circuit and the side of the rectangular module substrate. Then, they are arranged close to each other along two sides of the corner.

A large-scale integrated circuit incorporates a baseband processing circuit, and electric elements of an RF transceiver circuit are formed by a plurality of dielectric plates. The electric element includes a balun, a band-pass filter, a low-pass filter, a high-pass filter, and the like.

In order to reduce the antenna loss, two pairs of antennas having a dipole configuration for transmission and reception are used, and two pairs of conductor wires having a pair configuration are provided for the purpose of reducing the difference between the directional characteristics of the antennas and the size of the module substrate. Are arranged close to each other along two sides of two corners of a rectangular diagonal arrangement.

The conductor layer pattern of the pair of conductor wires may be formed in a straight line, a meander shape, or a helical shape, and any one may be selected to reduce the size of the module substrate.

A balun connected to a feed end of a pair of conductor wires of a balanced dipole antenna is formed by a part of a plurality of dielectric plates and is disposed near a corner of a module substrate.

In order to shorten the antenna length and reduce the size of the module substrate, a general ceramic is used as a dielectric plate having a large relative permittivity in which a conductor layer pattern of a pair of conductor wires is arranged therebetween. It is preferable to use an alumina plate having a ratio of about 9.0.

In order to reduce the influence on the antenna, a solder bump may be added to the surface of the module substrate opposite to the surface on which the large-scale integrated circuit is provided.

When a wireless module is mounted on a portable computer or a digital still camera having a metal housing as a portable wireless device, a dipole formed with a pair of conductor wires by forming an opening in a part of the metal housing. A module substrate having an antenna having the above configuration is arranged inside the opening and parallel to the surface of the housing.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on examples with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of an antenna device 4 of a transmitting / receiving module according to the present invention. A pair of conductor wires, which are dipole antennas, are formed by conductor layer patterns 5 and 6, and are arranged on a module substrate 11 composed of a plurality of dielectric plates 7, 8, 9 and 10 having a large relative dielectric constant. Conductor layer pattern 5 of a pair of conductor wires,
Numerals 6 are arranged at an angle of about 90 degrees, and are arranged close to each other along two sides 12 and 13 of the corners of the rectangular module substrate 11. Since the conductor layer patterns 5 and 6 are arranged inside the module substrate 11, they are indicated by broken lines.

The short-range wireless transmission / reception circuit of the Bluetooth standard is composed of circuits such as baseband processing and an RF transceiver. With low output, the minimum receiving sensitivity is -70dBm
Is set high. In the embodiment of FIG. 1, a large-scale integrated circuit 14 including at least a circuit for baseband processing is mounted on a module substrate 11.

The reason why the antenna having the dipole structure is formed by the conductor layer patterns 5 and 6 of the paired conductor wires is that the dipole antenna is a complete antenna, so that no other structure such as a ground plane is required. A wide ratio bandwidth and stable characteristics can be obtained. Since the antenna device 4 of the transmitting / receiving module of the present invention is intended to be used also for an antenna of a mobile phone or a portable digital device, it is important that the characteristic change of the antenna due to the presence or absence of a human body is small. Further, in order to reduce the size of the module substrate 11, it is necessary to eliminate the ground plate.

By arranging the conductor layer patterns 5 and 6 of the paired conductor wires between the plurality of dielectric plates 7 to 10 having a high relative dielectric constant, the antenna length can be shortened as compared with free space. When the whole is covered, the physical length, which is simply the antenna length of the conductor wire patterns 5 and 6, is inversely proportional to the half power of the relative dielectric constant. Also causes a difference in the degree of shortening. In order to shorten the antenna length, a ceramic plate having a large relative dielectric constant may be used instead of a resin plate having a small relative dielectric constant.

It is preferable to use a ceramic plate having a relative dielectric constant of 8.0 or more as a plurality of dielectric plates which constitute the module substrate 11 and arrange the conductor layer patterns 5 and 6 of the paired conductor wires therebetween. Alumina has a relatively large relative dielectric constant of 9.0 and can be generally said of ceramics. However, if the composition is selected, the value of the relative dielectric constant can be specified, the variation in the relative dielectric constant is small, and the loss coefficient is small. A small variation in the relative permittivity has a small shift in the frequency band of the antenna, and a small loss coefficient is advantageous for the antenna efficiency. For example, alumina is used as a general-purpose product among ceramics, and has a relative dielectric constant as large as about 9.0 and a small variation as compared with a resin material. In addition, the heat resistance is excellent, and the occurrence of defects in the terminal junction due to thermal stress when attaching the chip to the large-scale integrated circuit 14 is small.

The conductor patterns 5 and 6 of the pair of conductor wires are 9
Arranging at an angle of about 0 degrees allows the module substrate 11 to be smaller in size than an antenna having a dipole configuration in which conductor wires of a pair configuration are arranged on the same straight line, and at the same time,
This is advantageous for widening the directional characteristics to some extent. This is because narrow directionality is a problem when a direction and a position cannot be specified as in the case of a portable wireless device and an application range of wireless communication is limited.

A balun 15 of an electric element is arranged between the plurality of dielectric plates 7 to 10 constituting the module substrate 11. Further, electric elements such as band-pass filters, high-pass filters, and low-pass filters may be provided on the plurality of dielectric plates 7 to 10. These electrical elements form part of the circuit of the RF transceiver. A plurality of dielectric plates 7
Layer patterns 5, 6 of paired conductor wires between
By disposing the module substrate 11, the module substrate 11 can be used for shortening the antenna length and configuring the electric element. The plurality of dielectric plates is not limited to four as shown in FIG.

A large-scale integrated circuit is made of CMOS or a mixture of bipolar CMOS. When wireless communication is performed over a distance of 10 meters or more, an output of an RF transceiver is required. It becomes difficult to incorporate the transceiver circuit into one silicon chip. In addition, it is impossible to incorporate all circuits and electric elements in one chip, and it may not be reasonable.

The large-scale integrated circuit 14 is mounted on the module substrate 11
By providing them on the substrate, not only the area can be reduced, but also a plurality of electric elements formed on the module substrate 11 can be connected with a short wiring distance. A large-scale integrated circuit 14 that is resin-molded and has terminals 16 extending outward has a large area. A resin-molded large-scale integrated circuit having a joint terminal on the lower surface or a bare-chip integrated circuit may be used.

As shown in the embodiment of FIG. 1, when the conductor layer patterns 5 and 6 of the pair of conductor wires are arranged between the module substrates 11 formed by the plurality of dielectric plates 7 to 10, At the same time, the area and dimensions of the module substrate 11 can be reduced by being disposed in a relatively narrow range between the large-scale integrated circuit 14 and the two sides 12 and 13 of the module substrate 11. The conductor layer patterns 5, 6 of the pair of conductor wires are formed substantially linearly.

Another embodiment of the antenna device of the transmitting / receiving module of the present invention shown in FIG. 2 is shown in a perspective view. In the antenna device 17 of the transmission / reception module, meander-shaped conductor patterns 18 and 19 of paired conductor wires are formed between the large-scale integrated circuit 20 and the module substrate 21 including a plurality of dielectric plates.
It is arranged in a range between the side sides 22 and 23. If the meander-shaped conductor layer patterns 18 and 19 are arranged between a plurality of dielectric plates having a large relative dielectric constant, the antenna length can be further reduced. The size of the module substrate 21 can be reduced by reducing the antenna length of the meander-shaped conductor layer patterns 18 and 19.

A helical shape may be adopted as the conductor layer pattern of the pair of conductor wires forming the dipole antenna. The antenna device of the transmitting / receiving module of the present invention uses a module substrate on which a plurality of dielectric plates are stacked. Therefore, a helical conductor layer pattern of a pair of conductor wires may be formed in the same manner as a conventional method of forming a helical conductor pattern of a chip antenna. The helical shape can further reduce the antenna length than the meander shape. However, if the winding pitch is small, the specific bandwidth tends to be narrow. The antenna length refers to the linear length from the feeding end to the free end.

Another embodiment of the antenna device of the transmitting / receiving module of the present invention is shown in the perspective view of FIG. In FIG. 3A, a conductor layer pattern 24 of two pairs of conductor wires forming an antenna having a dipole configuration of transmission and reception at an angle of about 90 degrees,
25, 26, and 27, and a large-scale integrated circuit 29 disposed at the center of a module substrate 28 formed of a plurality of dielectric plates having a large relative dielectric constant and a diagonal arrangement of the module substrate 28. Between the respective sides 30, 31, and 32, 33 of the corner, the sides 30, 31, and 32,
33 are arranged in close proximity.

Conductor layer patterns 24, 2 of paired conductor wires
5 and 26 and 27 are arranged between a plurality of dielectric plates forming a module substrate 28. The conductor layer patterns 24, 25 and 26, 27 of the paired conductor wires are connected to the baluns 34 and 35 of the electric element.
6, 37 and 38, which are hidden along the sides 30, 31, and 32, 33 from the feeding end not shown. The baluns 34 and 35 are formed by a part of a plurality of dielectric plates, and are disposed near corners of the module substrate 28.

In FIG. 3B, a large-scale integrated circuit 39 which is resin-molded and has terminals on the lower surface is joined to a central portion of a module substrate 40 formed of a plurality of dielectric plates.
The two pairs of conductor wires 41, 42 and 43, 44 are connected to the large-scale integrated circuit 39 and the sides 45, 4 of the module substrate 40.
Between 6 and 47, 48, sides 45, 46 and 4
7 and 48 are disposed close together. Since the terminals are not extended outward from the side of the large-scale integrated circuit 39, the module substrate 40 can be easily reduced in size to some extent. However, it is assumed that the antenna length is shortened in the frequency band corresponding to the dipole antenna composed of the paired conductor wires 41, 42 and 43, 44.

Conductor layer patterns 41, 4 of paired conductor wires
The antenna length is shortened by providing 2, 43, and 44 in a module substrate 40 composed of a plurality of dielectric plates having a large relative permittivity. Electrical element baluns 49, 50
Is formed in a module substrate 40 composed of a plurality of dielectric plates. Conductor layer patterns 41, 42 of paired conductor wires
And 43 and 44 are formed from feed ends 51, 52 and 53 connected to baluns 49 and 50 and feed ends (not shown), and the large-scale integrated circuit 39 and sides 45, 46 and 47 of the module substrate 40. , 48.

FIG. 4 is a sectional view showing another embodiment of the antenna device of the transmitting / receiving module of the present invention. In FIG. 4A,
Module substrate 54 formed by stacking a plurality of dielectric plates
An electric element of at least a part of the RF transceiver circuit is formed in a region 55 indicated by a broken line. The electric element is a band-pass filter, a low-pass filter, a high-pass filter, a balun, or a capacitor in some cases. Terminals 57 and 58 extending outward from the large-scale integrated circuit 56 are connected to electric elements in the module substrate 54 or bonding terminals 61 on the lower surface of the module substrate 54 via via holes 59 and 60. The antenna length of the conductor layer patterns 62 and 63 forming a part of the dipole antenna is determined by the relative permittivity and the thickness of the plurality of dielectric plates.

In FIG. 4B, the RF is applied to a region 65 indicated by a broken line of a module substrate 64 composed of a plurality of dielectric plates.
A plurality of electrical elements of the transceiver circuit are formed. Helical conductor layer patterns 66 and 67, which are part of a pair of conductor wires of a dipole antenna, are arranged between a plurality of dielectric plates of the module substrate 64 to reduce the antenna length. A large-scale integrated circuit 68 having a built-in baseband processing circuit is mounted on a module substrate 64 in a bare chip state.
And terminals 69 and 70 of the large scale integrated circuit 68
A plurality of electric elements in the module substrate 64 or the bonding terminals 7 on the lower surface of the module substrate 64 through the via holes 73 and 74 from the conductive wires 71 and 72 bonded to the
5 is connected.

As shown in the embodiment of the antenna device of the transmitting / receiving module of the present invention shown in FIG.
In 68, the baseband processing circuit and the RF transceiver circuit are not all incorporated, but the baseband processing circuit is mainly incorporated.
At least some of the electrical elements of the RF transceiver circuit are provided in the module substrates,. Even in short-range wireless communication, when targeting a distance of 10 meters or more, it is necessary to increase the output of the RF transceiver. As a result, it becomes difficult to incorporate all the circuits in one chip.
Further, it may be more reasonable to integrally form an electric element such as a filter or a balun in a module substrate composed of a plurality of dielectric plates for the purpose of shortening a dipole antenna. Further, when a chip of an external electric element is required, it can be provided on the upper surfaces of the module substrates 54 and 55.

Further, via holes 59, 60 and 7 are formed from linear or meander-shaped conductor layer patterns 62 and 63 and helical conductor layer patterns 66 and 67, which are part of a pair of conductor wires constituting a dipole antenna.
The effect on the characteristics of the dipole antenna can be reduced by moving the various conductors such as 3, 74 and terminals as far away as possible. When joining the joining terminals 61 and 75 on the lower surfaces of the module boards 54 and 64 to another board, it is preferable to provide solder bumps.

The antenna device of the transmitting / receiving module of the present invention is a balanced system because it is an antenna having a dipole configuration.
Also, select the antenna length to resonate at half wavelength,
Make the impedance about 50 ohms. In order to reduce the reflection and improve the antenna efficiency, it is necessary to interpose a balanced-unbalanced converter and use a balanced-unbalanced converter having an impedance conversion ratio of 1: 1. When a balun, which is a balanced-unbalanced converter, is formed as a part of an electric element inside a module substrate composed of a plurality of dielectric plates, it is advantageous for reducing the size of the module substrate and reducing the mounting process load. If not, it is necessary to connect a balun chip, which is a parallel-to-unbalanced converter, to the feeding end of the dipole antenna.

When the antenna device of the transmitting / receiving module of the present invention is applied to the 2.4 GHz band, which is the Bluetooth standard for short-range wireless communication, a bandwidth of about 5% can be obtained and a demand of about 3.3% can be obtained. Can respond to. In addition, since the conductor wires of the pair configuration of the dipole antenna are arranged at an angle of about 90 degrees, compared with the dipole configuration of the dipole configuration arranged in parallel, the directional characteristics of the eyebrows are broader. Become.

The case where the antenna device of the transmitting / receiving module of the present invention is incorporated in a digital device and the head, head and hand, or hand is approached or grasped is compared with the case of the free state. When the changes in the fractional bandwidth and its center frequency are measured, they all fall within a small change within 1%. The antenna device of the present invention has a practically stable frequency band and a wide fractional bandwidth.

In the Bluetooth standard for short-range wireless communication, it is necessary to reduce transmission power as much as possible, and an efficient antenna device is required. If the efficiency is good, the output can naturally be suppressed. Since the antenna device of the transmitting / receiving module of the present invention has a dipole antenna, the antenna length is shortened, and the efficiency is relatively high even if the paired conductor wires are arranged non-parallel. Further, as shown in the embodiment of the present invention, by using two transmission and reception antennas exclusively, a transmission / reception module with low loss can be realized.

[0041] The target of the Bluetooth standard is a portable digital device. Some current portable computers and digital still cameras use a metal housing. Alternatively, a metal-plated resin may be used. In that case, the antenna device cannot simply be built in the housing. In addition, it is considered that there is no effective method other than taking out the conventional antenna device. The antenna device of the transmission / reception module of the present invention can be configured to be able to cope with a metal housing without deteriorating antenna characteristics and without protruding from the housing.

FIG. 5 shows a state in which the antenna device of the transmitting / receiving module of the present invention is mounted on a metal casing. In the case where the antenna device 77 of the transmitting / receiving module of the present invention is incorporated in a digital device using the metal housing 76 and used, a hole 78 is provided in the metal housing 76. The two dipole antennas composed of the conductor layer patterns 79, 80 and 81, 82 of the paired conductor wires are dimensioned to fit in the apertures 78 and are projected parallel to the surface of the metal housing 76. Placed without. When the influence of the metal casing 76 is measured as a 2.4 GHz band antenna device, the conductor layer patterns 79, 80, and 8 of the conductor wire paired with the edge 83 of the opening 78 are formed.
If the distance between the outer sides of 1, 82 is 3 mm,
The shift of the center frequency is within 50 MHz. If possible, conductor layer patterns 79, 80 and 8 of conductor wires in pairs
By not arranging 1, 82 and the edge 83 of the metal casing 76 in parallel, the change can be suppressed small.

[0043]

Since the antenna device of the present invention is configured as described above, it has the following advantages.

A small-sized module on which a large-scale integrated circuit including an antenna device and a transmitting / receiving circuit is mounted can be provided.

A module having a relatively wide specific bandwidth and directivity, requiring no ground plane, and having an antenna device having stable characteristics is possible.

An RF transceiver having a relatively large output can be mounted, and wireless communication of 10 meters or more is possible.

An antenna device that can support short-range wireless communication such as the Bluetooth standard and does not protrude even with a metal housing is possible.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an antenna device of a transmission / reception module of the present invention.

FIG. 2 is a perspective view showing another embodiment of the antenna device of the transmitting / receiving module of the present invention.

FIG. 3 is a perspective view showing another embodiment of the antenna device of the transmitting / receiving module of the present invention.

FIG. 4 is a sectional view of another embodiment of the antenna device of the transmitting / receiving module of the present invention.

FIG. 5 is an example of mounting the transmitting / receiving module of the present invention on a metal housing of the antenna device.

FIG. 6 shows a conventional antenna device formed with a conductor pattern on a resin substrate.

[Explanation of symbols]

4, 17, 77 Antenna device of transmitting / receiving module 5, 6, 24, 25, 26, 27, 41, 42, 43,
44, 62, 63, 79, 80, 81, 82 Conductor layer pattern of a pair of conductor wires 7, 16, 36, 55, 74, 80, 94, 103, 1
22, 133, 136, 11, 21, 28, 40, 5
4, 64 Module substrate composed of a plurality of dielectric plates 12, 13, 22, 23, 30, 31, 32, 33, 4
5, 46, 47, 48 Side 14, 20, 29, 39, 56, 68 Large-scale integrated circuit 18, 19 Conductor layer pattern of meander-shaped paired conductor wires 16, 57, 58 Terminals protruding outward 20, 21, 22, 23 Feeding end 59, 60, 73, 74 Via hole 61, 75 Junction terminal 66, 67 Conductor layer pattern 69, 70 of helical paired conductor wire Terminal 71, 72 Conduction of large scale integrated circuit Wire 76 metal housing

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J021 AA01 AB03 AB06 CA06 HA05 HA10 JA02 JA07 JA08 5J047 AA00 AA03 AB07 AB12 AB13 FD01 FD04 FD06 5K011 AA06 AA16 DA00 DA02 JA12 KA03 KA13

Claims (9)

[Claims] 1. An antenna used for wireless communication, wherein a dipole antenna is formed by a pair of conductor wires having a feed end in the center, and a plurality of dielectrics are mounted on a rectangular module substrate on which a large-scale integrated circuit is mounted. Using a board, a conductor layer pattern of the pair of conductor wires is disposed close to and along two sides at a position between two sides of the corner of the module substrate and the large-scale integrated circuit. An antenna device for a transmitting / receiving module, wherein a plurality of electric elements are constituted by the plurality of dielectric plates. 2. An antenna used for wireless communication, wherein said conductor layer patterns of two pairs of said conductor wires, which are antennas of a transmission and reception dipole configuration, are arranged in a diagonal arrangement of said rectangular module substrate. 2. The antenna device for a transmission / reception module according to claim 1, wherein the antenna device is arranged so as to be closely arranged along two sides of each of the corner portions. 3. The antenna device for a transmission / reception module according to claim 1, wherein in the antenna used for wireless communication, a baseband processing circuit is built in the large-scale integrated circuit. 4. An antenna used for wireless communication, wherein said electric element of a balun connected to a feed end of said pair of conductor wires is arranged near a corner of said module substrate. Item 3. An antenna device for a transmission / reception module according to item 1 or 2. 5. The transmitting / receiving module according to claim 1, wherein an antenna used for wireless communication has a configuration in which a conductor layer pattern of the pair of conductor wires is arranged between a plurality of dielectric plates. Antenna device. 6. The antenna device for a transmission / reception module according to claim 1, wherein said pair of conductor wires is formed by a linear conductor layer pattern in an antenna used for wireless communication. 7. The antenna device for a transmission / reception module according to claim 1, wherein in the antenna used for wireless communication, said pair of conductor wires are formed by a meander-shaped conductor layer pattern. 8. The antenna device for a transmission / reception module according to claim 1, wherein the pair of conductor wires is formed by a helical conductor layer pattern in an antenna used for wireless communication. 9. An antenna used for wireless communication, wherein an opening is formed in a part of a metal housing, and the pair of conductor wires are substantially parallel to a surface of the housing inside the opening. The antenna device for a transmission / reception module according to claim 1, wherein the antenna device is disposed at a position where the antenna is located.