JP2001298321A - Antenna module and radio communications equipment using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain thinning and to prevent a frequency bandwidth from becoming narrow. SOLUTION: On the bottom surface of a dielectric substrate 2, a recessed part 6 is formed and on the upper surface of a circuit board 3, a circuit 8 is formed on the area covered with the recessed part 6. A component 11A highest among plural circuit components 11 comprising the circuit 8 is located on the central area of the bottom surface of the recessed part 6. The central area of the bottom surface of the recessed part 6 is made deeper than the other area on the bottom surface of the recessed part. Since the circuit 8 is formed on the upper surface of the circuit board 3 and housed inside the recessed part 6, it is not necessary to provide the circuit 8 on the bottom surface of the circuit board 3 so that an antenna module 1 can be thinned accordingly. Since the terminal edge of the recessed part 6 remarkably related to narrowing of the frequency bandwidth is made shallow and only the central area of the recessed part 6, where an adverse influence to be exerted upon the frequency bandwidth is reduced, is made deep corresponding to the highest component, narrowing of the frequency bandwidth can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna module and a radio communication device using the same.

[0002]

2. Description of the Related Art FIG. 8 is a perspective view showing an example of an antenna module. This antenna module 30
Is, for example, DAB (Digital Audio Broadcast) or G
It transmits and receives circularly polarized radio waves used in communication systems such as the PS (Global Positioning System).
The antenna unit 31 includes a circuit board 32, a circuit including a power supply circuit (not shown) (hereinafter, referred to as a module built-in circuit), and a shield case 33. It has a body 35, a radiation electrode 36, and a power supply pin 37.

That is, as shown in FIG. 8, a circular radiating electrode 36 is formed on the upper surface of a rectangular parallelepiped dielectric substrate 35 to constitute an antenna unit 31. It is disposed on the upper surface of the circuit board 32 with the bottom surface of the body base 35 as a mounting surface. On the bottom surface of the circuit board 32, a module built-in circuit including a power supply circuit for supplying power to the radiation electrode 36 is formed.
6 are connected to the circuit board 3.
2 and the dielectric substrate 35. On the bottom side of the circuit board 32, a shield case 33 that covers the module built-in circuit with a space therebetween and shields the module built-in circuit is provided.

In the antenna module 30 shown in FIG. 8, power is directly supplied from the module built-in circuit to the radiation electrode 36 via the power supply pin 37, and the power supply excites the radiation electrode 36 to produce a circular shape. Transmission and reception of polarized radio waves are performed.

[0005]

In the antenna module 30 having the structure shown in FIG. 8, as described above, the circuit board 3
The antenna unit 31 is provided on the upper surface side of the antenna module 2, and the module built-in circuit and a shield case 33 that covers the circuit with an interval are provided on the bottom surface side of the circuit board 32. It was bulky. In recent years, there has been a demand for a smaller and thinner antenna module, but it has been difficult to satisfy the demand.

Accordingly, the present inventor has devised the following antenna module in order to meet the above demand for miniaturization. FIG. 7 shows a cross-sectional view of the proposed antenna module. In the antenna module 30 shown in FIG. 7, a concave portion 40 is formed on the bottom surface of the dielectric substrate 35 of the antenna unit portion 31, and a module built-in circuit is formed on the upper surface of the circuit board 32 in a region covered by the concave portion 40. I have. Reference numeral 42 shown in FIG. 7 represents a component of the module built-in circuit.

[0007] A shield film 41 is formed on the inner peripheral surface of the recess 40 so as to cover the module built-in circuit and shield the module built-in circuit.

In the antenna module 30 shown in FIG. 7, since the module built-in circuit and the shielding means are accommodated in the recess 40 of the dielectric substrate 35, the module built-in circuit and the shielding means are provided on the bottom side of the circuit board 32. Since the antenna module 30 need not be provided, the antenna module 30 can be made thinner and smaller.

However, in the configuration shown in FIG. 7, the depth of the concave portion 40 is equal over the entire area of the concave portion, and the depth H is the same as the depth of the plurality of circuit components 42 constituting the module built-in circuit. The depth is such that the tallest and tallest part 42A can be accommodated. For this reason, if the tallest component 42A in the module built-in circuit is high, the distance between the radiation electrode 36 and the shield film 41 is narrowed over the whole, and as a result, the frequency bandwidth of radio wave transmission and reception is narrowed. Problem arises.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to promote size reduction and thickness reduction, and to prevent narrowing of a frequency bandwidth of radio wave transmission / reception. And a wireless communication device using the same.

[0011]

Means for Solving the Problems In order to achieve the above object, the present invention has the following structure to solve the above problems. That is, in the antenna module of the first invention, a radiation electrode for transmitting and receiving radio waves is formed on the upper surface of the dielectric substrate to form an antenna unit, and the antenna unit is mounted on a circuit using the bottom surface of the dielectric substrate as a mounting surface. An antenna module mounted on an upper surface of a substrate, wherein a concave portion is formed on a bottom surface of the dielectric substrate of the antenna unit portion, and an area covered by the concave portion of the dielectric substrate is formed on an upper surface of the circuit board. A circuit including a power supply circuit for the radiation electrode is formed, and the tallest and tallest component of the plurality of circuit components constituting the circuit is located at the bottom center region of the concave portion of the dielectric substrate. The central part of the bottom surface of the concave portion has a depth greater than that of the other region of the bottom surface of the concave portion.

An antenna module according to a second aspect of the present invention includes the configuration of the first aspect, wherein a plurality of circuit components inside the concave portion of the dielectric substrate have a height from the central region of the concave portion toward the edge region of the concave portion. Are arranged in ascending order, and the depth of the bottom surface of the concave portion is gradually or continuously reduced from the central region toward the edge region.

An antenna module according to a third aspect of the present invention has the structure of the first or second aspect, and a high-profile dummy component is provided on the upper surface of the circuit board at a position opposed to the center of the bottom surface of the concave portion of the dielectric substrate. A positioning fitting portion is formed in the center region of the bottom surface of the concave portion so as to fit the tip side of the tall dummy component.

A wireless communication apparatus according to a fourth aspect of the present invention is characterized in that the antenna module according to the first, second, or third aspect of the present invention is provided.

In the invention having the above structure, a concave portion is formed on the bottom surface of the dielectric substrate of the antenna unit portion, and a circuit is formed on an upper surface of the circuit board in a region covered by the concave portion of the dielectric substrate. The tallest component among the components of the circuit is disposed at a position that is the central region of the bottom surface of the concave portion of the dielectric substrate, and the depth of the central region of the concave bottom surface is deeper than other regions of the concave bottom surface. Has become.

In the present invention, as described above, the circuit including the power supply circuit for the radiation electrode is formed on the upper surface of the circuit board, and the circuit is accommodated in the concave portion of the dielectric substrate. Since it is unnecessary to form the antenna module, the antenna module can be made thinner and smaller.

Further, according to the present invention, as described above, the tallest component among the components of the circuit is disposed at a position corresponding to the bottom central region of the concave portion of the dielectric substrate, and the concave bottom central region is provided. Is deeper than other areas. Thus, the central area of the bottom of the recess is deeper to accommodate the tallest components, while the other area of the bottom of the recess is shallower than its central area. Since the depth of the central region of the bottom surface of the recess has a smaller adverse effect on the frequency bandwidth than the other regions of the bottom surface of the recess, even if the depth of the central region of the bottom surface of the recess is increased, the depth of the other region of the bottom surface of the recess is reduced. Since the depth is shallow, narrowing of the frequency bandwidth of radio wave transmission / reception of the radiation electrode can be suppressed.

[0018]

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

FIG. 1A is a perspective view showing an antenna module according to a first embodiment of the present invention.
FIG. 1B schematically shows a state in which the antenna unit constituting the antenna module shown in FIG. 1 is divided in half by an AA part shown in FIG. 1A, and FIG. 1
A sectional view of an AA portion of the antenna module shown in FIG.

The antenna module 1 shown in FIGS. 1A to 1C is capable of transmitting and receiving a circularly polarized radio wave used in a communication system such as DAB or GPS, and has a cylindrical dielectric structure. The base body 2 has a form mounted on a circuit board 3. The dielectric substrate 2 is made of a dielectric material such as ceramics, and a circular radiation electrode 4 is disposed on the upper surface of the dielectric substrate 2 with its center positioned on the central axis of the dielectric substrate 2. Have been. A power supply electrode 5 is formed on the side surface of the dielectric substrate 2 with an interval from the radiation electrode 4. Further, a concave portion 6 is formed on the bottom surface of the dielectric substrate 2. This recess 6 is shown in FIG.
As shown in (c), the dielectric substrate 2 has a symmetrical shape with respect to the central axis.

In the first embodiment, an antenna unit 7 is constituted by the dielectric substrate 2, the radiation electrode 4 and the feed electrode 5.

The circuit board 3 is made of a dielectric material such as ceramics, and the dielectric material has a dielectric constant larger than that of the dielectric substrate 2, for example. On the upper surface of the circuit board 3, a module built-in circuit 8 is formed in a region R covered by the concave portion 6 of the dielectric substrate 2. The module built-in circuit 8 is a circuit including a power supply circuit for the radiation electrode 4, and includes, for example, the power supply circuit and an amplifier circuit. Reference numerals 11 shown in FIGS. 1B and 1C represent components constituting the module built-in circuit 8.

The most characteristic feature of the first embodiment is that the tallest and tallest component 11A of the plurality of circuit components 11 of the module built-in circuit 8 is the concave portion 6 of the dielectric substrate 2. And a center portion of the bottom surface of the recess is formed with a recess 12 for accommodating the top end of the tallest component 11A. The depth of the central region is deeper than other regions of the bottom surface of the concave portion.

On the inner peripheral surface of the concave portion 6 of the dielectric substrate 2 (including the inner peripheral surface of the concave portion 12 for accommodating the tallest component), a shield film for covering and shielding the module built-in circuit 8 with an interval therebetween. 10 is formed using a film forming technique. On the upper surface of the circuit board 3, a wiring pattern (not shown) for electrically connecting the module built-in circuit 8 and the power supply electrode 5 on the side surface of the dielectric substrate 2 is formed. On the upper surface, a ground electrode (not shown) is formed so as to surround the wiring pattern and the module built-in circuit 8 with a space therebetween.

Further, a ground electrode (not shown) is formed on the bottom surface of the dielectric substrate 2 except for the region (non-ground region) where the wiring pattern contacts. And the ground electrode on the upper surface of the circuit board 3 are joined and electrically connected.
The module built-in circuit 8 together with the shield film 10
And shield the wiring pattern.

The antenna module 1 shown in the first embodiment is configured as described above. In the antenna module 1, when power is supplied from the module built-in circuit 8 to the power supply electrode 5 via the wiring pattern,
The supplied power is transmitted from the power supply electrode 5 to the radiation electrode 4 by capacitive coupling. The power supply excites the radiation electrode 4 to transmit and receive a circularly polarized radio wave.

According to the first embodiment, the concave portion 6 is provided on the bottom surface of the dielectric substrate 2, and the module built-in circuit 8 is formed on the upper surface of the circuit board 3 in a region covered by the concave portion 6. Since the shield film 10 is formed on the inner peripheral surface of the concave portion 6, the module built-in circuit 8 and the shielding means (shield film 10) are accommodated inside the concave portion 6 of the dielectric substrate 2. And shielding means need not be provided on the bottom side of the circuit board 3.
The antenna module 1 can be made thinner.

In addition, in the first embodiment, as described above, the tallest part 11A of the module built-in circuit 8 is disposed at a position that is the bottom central region of the recess 6, and the depth of the bottom central region of the recess 6 is increased. Since a characteristic configuration is provided in which the depth is made deeper than other regions of the bottom surface of the concave portion, it is possible to prevent the frequency bandwidth of radio wave transmission and reception from being narrowed.

That is, since the central region of the radiation electrode 4 has a weak electric field, even if the distance between the central region of the radiation electrode and the shield film 10 on the inner peripheral surface of the concave portion 6 becomes narrow, this distance is kept small. Adversely affect the frequency bandwidth of the radiation electrode 4. Further, the electric field is dense in the edge region of the radiation electrode 4, and the radiation electrode edge region and the shield film 1
When the interval between the radiating electrodes 4 is small, the frequency bandwidth of the radiation electrode 4 is reduced due to the narrowing of the interval. However, in the first embodiment, as described above, the edge of the bottom surface of the concave portion 6 is formed. Since the configuration is such that the depth of the region can be made shallow and the interval between the radiation electrode edge region and the shield film 10 can be suppressed from becoming narrow, the frequency bandwidth of the radiation electrode 4 for radio wave transmission and reception is narrowed. Can be prevented.

Further, in the first embodiment, the recess 6
Is provided on the bottom surface of the antenna module 1. In the manufacturing process of the antenna module 1, the dielectric substrate 2 is mounted on the circuit board so that the tallest component 11A fits in the concave portion 12 for accommodating the highest component. By simply placing the dielectric substrate 2 on the circuit board 3, the dielectric substrate 2 and the circuit board 3 can be easily aligned and the dielectric substrate 2 can be mounted on the circuit board 3.
Thus, the time required for mounting the circuit board 3 on the dielectric substrate 2 can be reduced, and the dielectric substrate 2
In addition, the positional accuracy of mounting the circuit board 3 can be improved.

Although the shield film 10 is formed as the shield means in the first embodiment, for example, instead of the shield film 10, as shown in FIG.
A shield case 14 that covers the module built-in circuit 8 with an interval therebetween may be provided inside the recess 6 as a shield means.

Hereinafter, a second embodiment will be described. In the description of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the overlapping description of the common portions will be omitted.

The characteristic configuration of the second embodiment is particularly effective when there are a plurality of tall components among the plurality of circuit components 11 of the module built-in circuit 8. That is, as shown in FIGS. 3A and 3B,
The plurality of circuit components 11 of the module built-in circuit 8 are arranged in order of decreasing height from the central area of the bottom surface of the concave portion 6 toward the edge region, and the depth of the bottom surface of the concave portion 6 from the central region. As one approaches the edge area, FIG.
This shallower gradually as shown in FIG. 3A or continuously as shown in FIG. 3B. Other configurations are the same as those of the first embodiment.

According to the second embodiment, since the configuration similar to that of the first embodiment is provided, the antenna module 1 can be made thinner as in the first embodiment. The effect described above can be achieved. In addition, in the second embodiment, a plurality of circuit components 11
Are arranged in order of decreasing height from the central region of the bottom surface of the recess toward the edge region of the bottom surface of the recess, and the depth of the bottom surface of the recess is made shallower from the central region toward the edge region. It is possible to further suppress the depth of the edge region of the concave portion, which is particularly likely to adversely affect the narrowing. In particular, even if there are a plurality of tall components, the depth of the recess edge region that greatly contributes to the frequency bandwidth can be reduced, so that the narrowing of the frequency bandwidth can be avoided. Can be obtained.

Hereinafter, a third embodiment will be described. The feature of the third embodiment is that, as shown in FIG. 4, a tall dummy component 16 is provided on the upper surface of the circuit board 3 at a position facing the bottom center region of the concave portion 6 of the dielectric substrate 2. In addition, a positioning fitting portion 17 is provided on the bottom surface of the concave portion 6 so that the tip side of the dummy component fits. The other configurations are the same as those of the above-described embodiments. In the description of the third embodiment, the same components as those of the above-described embodiments are denoted by the same reference numerals, and the description of the common portions will not be repeated. I do.

In the third embodiment, as described above, the dummy component 16 is disposed on the upper surface of the circuit board 3 at a position corresponding to the central region of the bottom surface of the concave portion 6. This dummy part 16
Is taller than the tallest circuit component 11A of the module built-in circuit 8, for example. The positioning fitting portion 17 has a shape and a size that allow the front end side of the dummy component 16 to be fitted without play.

According to the third embodiment, since it has the same configuration as each of the above embodiments, the same effects as those of each of the above embodiments can be obtained. In particular, this third
In the embodiment, as described above, since the dummy component 16 and the positioning fitting portion 17 are provided, in the manufacturing process, the positioning of the mounting of the dielectric substrate 2 on the circuit board 3 is further facilitated, and In addition, the positional accuracy of mounting the dielectric substrate 2 on the circuit board 3 can be improved.

Hereinafter, a fourth embodiment will be described. In the fourth embodiment, an embodiment of the wireless communication apparatus according to the present invention will be described. FIG. 5 is a block diagram showing a main configuration example of the wireless communication apparatus according to the fourth embodiment. The wireless communication device of the fourth embodiment is a communication device using DAB, and the feature of this wireless communication device is that the antenna module 1 shown in each of the above embodiments is provided. . In the fourth embodiment, the configuration of the antenna module 1 has been described in each of the above embodiments, and a duplicate description thereof will be omitted.

As shown in FIG. 5, this wireless communication device
The antenna module 1, the receiving unit 22, the signal processing unit 23, the interface unit 2
4 and a display unit 25.
In such a wireless communication device, for example, the receiving unit 22
, A radio signal received by the antenna module 1 is added. The receiving unit 22 extracts predetermined various signals from the added radio signal and outputs the signals to the signal processing unit 23. The signal processing unit 23 performs signal processing on the received signal according to a predetermined method, and performs display control and the like on the display 25 in cooperation with an interface unit 24 such as a remote controller.

According to the fourth embodiment, since the radio communication device is constituted by using the antenna module 1 as shown in each of the above embodiments, it is possible to reduce the size and thickness of the radio communication device. it can. Further, since the narrowing of the frequency bandwidth for radio wave transmission and reception is suppressed, a wireless communication device with high reliability of antenna performance can be provided.

It should be noted that the present invention is not limited to the above embodiments, but can take various embodiments. For example, in each of the above embodiments, the antenna module 1 transmits and receives a circularly polarized radio wave. However, the present invention can of course be applied to an antenna module that transmits and receives a linearly polarized radio wave. . Thus, the present invention can be applied not only to circularly polarized waves but also to an antenna module capable of transmitting and receiving radio waves other than circularly polarized waves.
The shape of the dielectric substrate 2 and the shape of the radiation electrode 4 are not limited to the above embodiments, but may take various shapes.

The concave portion 6 on the bottom side of the dielectric substrate 2
Are not limited to the shapes shown in the above embodiments, and may take various shapes, for example, as shown in FIGS. 6 (a), 6 (b) and 6 (c).

Further, in the fourth embodiment, an example of a communication device using DAB is shown as a wireless communication device equipped with the antenna module 1 shown in the first to third embodiments. The antenna module having a specific configuration according to the present invention can be incorporated in a wireless communication device other than the communication device using the DAB.

[0044]

According to the present invention, the concave portion is provided on the bottom surface of the dielectric substrate, and the circuit is formed on the upper surface of the circuit board in a region covered by the concave portion of the dielectric substrate. The antenna module is housed and arranged inside the concave portion of the base, and the circuit is not required to be provided on the bottom side of the circuit board as compared with the case where the circuit has to be formed on the bottom side of the circuit board. Bulkiness can be prevented, and the antenna module can be made thinner and smaller.

According to the present invention, the tallest component of the plurality of circuit components constituting the circuit is disposed at a position which is the central region of the bottom surface of the concave portion, and the depth of the central region of the bottom surface of the concave portion is It is deeper than other areas on the bottom. Thus, the central area of the bottom of the recess is deeper to accommodate the tallest components, while the other area of the bottom of the recess is shallower than the central area. Since the depth of the central region of the bottom surface of the recess has a smaller adverse effect on the narrowing of the frequency bandwidth than the other regions of the bottom surface of the recess, even if the depth of the central region of the bottom surface of the recess is deepened, In other words, the depth of the region, that is, the depth of the region that is likely to affect the narrowing of the frequency bandwidth is reduced, and the thickness of the dielectric substrate between the radiation electrode on the top surface of the dielectric substrate and the bottom surface of the concave portion is increased. Therefore, the narrowing of the frequency bandwidth of radio wave transmission / reception of the radiation electrode can be suppressed.

A plurality of circuit components are arranged in order of decreasing height from the central region of the concave portion to the edge region of the concave portion, and the depth of the bottom surface of the concave portion is stepwise from the central region to the edge region. In the case where the depth is gradually or continuously reduced, it is possible to further suppress the depth of the recess edge region, which is particularly likely to adversely affect the narrowing of the frequency bandwidth. In particular, even if there are multiple tall circuit components,
Since the depth of the recess edge region can be reduced, the narrowing of the frequency bandwidth can be reliably avoided when there are a plurality of tall circuit components, which is effective.

A tall dummy component is disposed on the upper surface of the circuit board at a position opposite to the center region of the bottom surface of the concave portion, and a positioning fitting in which the tall dummy component is fitted in the central region of the bottom surface of the concave portion. In the case where the mating portion is formed, simply mounting the dielectric substrate on the circuit board by fitting the dummy component into the positioning fitting portion, the dielectric material can be easily placed on the circuit board. The base can be aligned and mounted.
Thus, the time required for mounting the dielectric substrate on the circuit board can be reduced, and the positional accuracy of mounting the dielectric substrate on the circuit board can be increased.

In the wireless communication device provided with a unique antenna module according to the present invention, the size of the wireless communication device can be reduced as the size of the antenna module is reduced as described above. Further, since an antenna module that can avoid narrowing of the frequency bandwidth is provided, a wireless communication device with high reliability of antenna characteristics can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an antenna module according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing another example of the shield means.

FIG. 3 is an explanatory diagram showing an antenna module according to a second embodiment.

FIG. 4 is an explanatory diagram illustrating an antenna module according to a third embodiment;

FIG. 5 is an explanatory diagram illustrating an example of a wireless communication device according to a fourth embodiment;

FIG. 6 is an explanatory diagram showing another embodiment.

FIG. 7 is an explanatory diagram showing a configuration example of an antenna module in a development stage before the antenna module of the present invention.

FIG. 8 is an explanatory diagram showing an example of a conventional antenna module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna module 2 Dielectric substrate 3 Circuit board 4 Radiation electrode 5 Feeding electrode 6 Concave part 7 Antenna unit part 8 Circuit 11 Circuit component part 16 Dummy part 17 Alignment fitting part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsuyuki Yuasa 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd. (72) Inventor Tsune Akiyama 2-26-10 Tenjin, Nagaokakyo-shi Kyoto F-term in Murata Manufacturing (reference) 5J021 AA01 AB06 CA02 CA06 FA00 JA02 JA07 JA08 5J045 AB05 CA04 DA10 EA07 LA01 MA01 NA02 NA06 5J046 AA03 AA07 AA12 AB13 PA07 SA00

Claims (4)

[Claims] An antenna unit is formed by forming a radiation electrode for transmitting and receiving radio waves on an upper surface of a dielectric substrate, and the antenna unit is mounted on an upper surface of a circuit board with a bottom surface of the dielectric substrate as a mounting surface. A concave portion is formed on the bottom surface of the dielectric substrate of the antenna unit, and a power supply circuit for the radiation electrode is formed on an upper surface of the circuit board in a region covered by the concave portion of the dielectric substrate. Is formed, and the tallest and tallest component among a plurality of circuit components constituting the circuit is disposed at a position which is a bottom central region of the concave portion of the dielectric substrate. An antenna module characterized in that the depth of the central region of the bottom surface of the recess is deeper than other regions of the bottom surface of the recess. 2. A plurality of circuit components inside the concave portion of the dielectric substrate are arranged in order of decreasing height from the central region of the concave portion toward the edge region of the concave portion, and the bottom of the concave portion has a depth of the central region. 2. The antenna module according to claim 1, wherein the depth decreases stepwise or continuously from the edge toward the edge region. 3. A tall dummy component is disposed on the upper surface of the circuit board at a position facing the center of the concave bottom surface of the dielectric substrate, and the tall dummy component is disposed in the center of the concave bottom surface. The antenna module according to claim 1, wherein a positioning fitting portion to which a tip side is fitted is formed. 4. A wireless communication device comprising the antenna module according to claim 1, 2, or 3.