JP2003234615A - Slot antenna and radio lan card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the rigidity of the entire card by integrating the circuit part and antenna part of a radio LAN card by a metallic case, to compact the card by equalizing a thickness of both parts and to constitute a slot antenna by a slot directly provided on a case surface. <P>SOLUTION: A card outer shape is formed by covering the circuit part and the antenna part by an integrated metallic case, power is fed from a microstrip line provided on a printed board to the slot provided on the surface on the antenna part side of the case and the slot antenna is formed. Also, inside the case, the circuit part and the antenna part are separated by a block for radio interference prevention. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless LAN card and a slot antenna used in the wireless LAN card.

[0002]

2. Description of the Related Art FIG. 14 shows a configuration example of a conventional wireless LAN card (wireless network I / F card). Wireless L
An AN card is considered as a constituent part and is roughly divided into a circuit part (a) and an antenna part (b). The circuit portion a is a portion where a predetermined circuit for communication is formed on a printed board. The antenna part b is a part in which an antenna unit of a predetermined system is formed. In this wireless LAN card, a slot antenna unit is built in the antenna part b. Slots are formed on the back side of the printed circuit board so as to be orthogonal to the microstrip lines on the printed circuit board. As a result, power is supplied to the slot to function as a slot antenna.

In the conventional wireless LAN card as described above, a metal case is used as the outer case (cover) in the circuit portion a in order to maintain rigidity. On the other hand, in the antenna part b, an antenna unit of a predetermined method is built in the case, and a case (cover) made of a dielectric material such as plastic resin is used so that electromagnetic waves can be radiated for transmission and reception of radio waves.

As an example of the conventional antenna as described above, there is a diversity antenna disclosed in Japanese Patent Laid-Open No. 2000-124735. Even with this antenna unit,
A dielectric material is used for the cover (case) of the antenna section.

In the conventional wireless LAN card, there is a problem that rigidity is weakened because the boundary between the circuit portion a and the antenna portion b serves as a connection point of parts made of different materials. In addition, since it is composed of different parts, it is a cause of an increase in the number of parts and the number of assembling steps even if the manufacturing cost is taken into consideration. Further, even if the case of the antenna part b is formed of a metal case and a slot is formed on the case surface, the distance between the microstrip line on the printed circuit board and the slot provided on the case surface becomes unstable. Therefore, there is a problem that electromagnetic coupling is not performed well.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and increases the rigidity of the entire card by integrating the circuit portion and the antenna portion of the card with a metal case. It is an object of the present invention to provide a wireless LAN card in which the thickness of the parts is the same and the card is compact. Another object of the present invention is to provide a slot antenna constituted by a slot provided directly on the case surface and a wireless LAN card provided with this slot antenna.

Still another object is to provide a wireless LAN card having two slot antennas in the antenna section.

Still another object of the present invention is to provide a wireless LAN card in which the formation position and shape of the slot in the antenna part are devised.

[0009]

In order to achieve the above object, the invention according to claim 1 is formed by feeding power from a microstrip line provided on a printed circuit board to a slot provided on a metal case surface. It is characterized by being done.

According to a second aspect of the present invention, the circuit part and the antenna part are covered with an integrated metal case to form the outer shape of the card, and from the microstrip line provided on the printed circuit board to the antenna part side of the case. It is characterized in that a slot antenna is formed by feeding power to a slot provided on the surface, and a circuit part and an antenna part are separated by a block for preventing radio wave interference in the case, and the slot is sealed with a seal. .

A third aspect of the invention is characterized in that, in the second aspect of the invention, two slot antennas are formed in the antenna portion.

The invention according to claim 4 is characterized in that, in the invention according to claim 3, a block for preventing radio wave interference is formed at a boundary between two slot antennas.

According to a fifth aspect of the present invention, in the invention according to any one of the second to fourth aspects, the slot is provided in an L shape on the upper surface (front surface) of the case.

The invention according to claim 6 is characterized in that, in the invention according to any one of claims 2 to 4, the slot is provided in a horizontal direction on a side surface of the case.

The invention according to claim 7 is characterized in that, in the invention according to any one of claims 2 to 4, the slot is provided horizontally on the side surface over the upper surface and one side surface of the case. There is.

The invention according to claim 8 is characterized in that, in the invention according to any one of claims 2 to 4, the slot is provided in the vertical direction on the side surface over the upper surface and the two side surfaces of the case. There is.

The invention according to claim 9 is the invention according to any one of claims 2 to 4, characterized in that the slot is provided in a U-shape on the upper surface of the case.

The invention described in claim 10 is characterized in that, in the invention described in claim 3 or 4, two slots are provided at right angles to each other on the upper surface of the case so as to enable polarization diversity.

The invention according to claim 11 is the invention according to claims 2 to 4.
In the invention described in any one of the above 1 to 3, the slot is characterized in that a slot end is formed on the upper surface at the center of the side surface across the upper surface and two side surfaces of the case.

The invention as defined in claim 12 is from claim 2 to claim 1.
The invention according to any one of items 1 to 1 is characterized in that the circuit portion of the case and the antenna portion have the same thickness.

The invention as defined in claim 13 is from claim 2 to claim 1.
In the invention described in any one of 1, the antenna part side of the case is formed thicker than the circuit part side, and the distance between the slot and the microstrip line is set to a predetermined distance for resonance. .

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a perspective view showing the external appearance of a wireless LAN card 100 according to the first embodiment of the present invention. 2 is an internal configuration diagram of the wireless LAN card 100 according to the first embodiment of the present invention. The wireless LAN card 100 of the first embodiment is
It has a case 1, a printed circuit board 2, a microstrip line 3, a slot 4, and a block 6.

In FIG. 1, a wireless LAN card 100 has an outer shape formed by a metal case (cover) 1 in which a circuit portion a and an antenna portion b are integrated. In addition, a slot 4 having a predetermined shape is provided at a predetermined position on the surface (upper surface) of the case 1b, which is a portion of the case 1 on the antenna portion b side. Figure 1
In, two L-shaped slots 4 are provided. The slot 4 is provided in the surface of the case 1 by cutting out an elongated hole. A seal 8 is adhered to the upper surface of the case 1b to close the slot 4. The seal 8 is for preventing dust, water droplets, and the like from entering the case 1b through the slot 4, and is an extremely thin resin sheet having an adhesive applied to the back surface.

The case 1 is manufactured by pressing a thin metal plate, and is PCMCI which is a standard for personal computer cards.
The shape conforms to A. For example, the width of the card is about 54m
m and the thickness is about 5 mm. Wireless LAN card 100
The case 1 is configured such that the circuit portion a and the antenna portion b have almost the same thickness.

In FIG. 2, a printed circuit board 2 is enclosed in a case 1, and a predetermined circuit for communication is formed in a portion of the printed circuit board 2 on the side of the circuit portion a (what is the gist of the present invention). The description is omitted because it is not related). A microstrip line 3 is formed on the surface of the printed board 2 and extends up to the antenna portion b side portion of the printed board 2.
The microstrip line 3 and the slot 4 provided on the upper surface of the case 1b are spatially orthogonal to each other. As a result, the microstrip line 3 and the slot 4 are electromagnetically coupled, power is supplied to the slot 4, and the slot antenna 5 functions. A predetermined space is provided between the microstrip line 3 and the slot 4.

Inside the case 1, the circuit section a and the antenna section b are separated by the block 6 for preventing radio wave interference.
Maintain antenna characteristics. Further, the two slot antennas 5 are also separated by the block 6 to maintain the antenna characteristics (in the T-shaped block 6, a block part 61 separating the circuit part a from the antenna part b is 61, and the slot antenna 5 is separated). The block portion to be separated is designated as 62).

The block 6 is made of a metal (such as aluminum), a conductive sponge, or a conductor (having a radio wave shielding effect) such as a metal-plated plastic resin as its material. In the microstrip line 3 on the surface of the printed board 2, the circuit part a side and the antenna part b side are connected through a notch provided in the block 61.

As the constitution of the wireless LAN card of the present invention,
A configuration in which one or two slot antennas 5 are provided on the card is possible. In this embodiment, a wireless LAN card equipped with two slot antennas 5 is described. The two slot antennas 5 are installed here as a diversity (diversity) as a wireless LAN system.
sity) (particularly spatial diversity), and even one can be implemented.

FIG. 3 is a view of the wireless LAN card 100 as seen from above. On the surface of the printed board 2, the microstrip line 3 is provided with a stub 7 for impedance adjustment.

FIGS. 4 and 5 are views for explaining the structural relationship between the block 6 and the printed circuit board 2. The T-shaped block 6 is made of the same material as the block 61 at the boundary between the antenna part a and the circuit part b and the block 62 between the slot antennas 5 and has an integrated structure. In this embodiment, the printed circuit board 2 is vertically sandwiched by two T-shaped components forming the T-shaped block 6.

If the length of the slot 4 (the length of the long side) is about ½ of the wavelength used for communication, the antenna operates efficiently. Card 10 of the first embodiment
At 0, the slot 4 has an L shape in order to make the area occupied by the antenna portion b as a result of the shape as narrow as possible. The width (length of the short side) of the slot 4 is set to a predetermined width so that the radiation efficiency as a slot antenna is high. The slot width is usually a very small value for the wavelength used.

The microstrip line 3 has a slot 4
And the slot antenna 5 which is efficiently electromagnetically coupled to
Are arranged so as to be orthogonal to each other at a predetermined position such that the input impedance becomes 50Ω.

The end of the microstrip line 3 is electrically open or short-circuited. When opening
The microstrip line 3 serves as a termination to which nothing is connected. When short-circuited, a through hole is formed at the end of the microstrip line 3. The through hole is formed by providing a hole in the printed board 2, performing metal plating on the inner diameter of the hole, and connecting the microstrip line 3 and the ground conductor on the back side of the printed board 2.

When the stub 7 is formed on the microstrip line 3, the microstrip line 3 and the slot 4 are well coupled and impedance matching is facilitated. As the stub 7, an open stub or a short stub can be used to adjust the impedance by its thickness or length.

FIG. 6 is a comparison diagram of electromagnetic radiation patterns of the conventional wireless LAN card and the wireless LAN card 100 of the present embodiment. In the wireless LAN card 100, the slot 4 is provided on the front surface (upper surface) of the case 1b,
Since it is not provided on the back surface (lower surface) of the card, the antenna gain to the back surface of the card is small, and radio waves can be efficiently radiated in the azimuth direction or the zenith direction of the card. Further, by providing the block 6, the antenna characteristics can be stably maintained without being affected by the circuit section a.

The operation of the wireless LAN card 100 of this embodiment during communication will be described. As an operation during radio wave transmission, the signal transmitted from the circuit portion a side through the microstrip line 3 is transmitted to the slot 4 side at the intersection of the microstrip line 3 and the slot 4. Slot 4
Above, the electric field resonates at a desired frequency, and the signal is converted into an electromagnetic wave to be emitted into the air.

When receiving a radio wave, the signal path is opposite to that when transmitting. Electromagnetic waves propagated from the air are slot 4
Is converted into a signal in and transmitted to the circuit section a via the microstrip line 3.

Next, another embodiment of the present invention will be described. As another embodiment, a wireless LAN card in which the shape and position of the slot 4 provided on the surface of the case 1b is changed is shown in FIGS.
2 shows.

First, FIG. 7 shows the configuration of the wireless LAN card 200 of the second embodiment. In the wireless LAN card 200, the slot 42 is formed on the side surface of the case 1b. As an effect of such a configuration, the card 20
It is possible to emit vertically polarized waves with respect to the azimuth direction of 0. In general, the polarization in the wireless LAN system is vertical, and the direction of arrival of radio waves is often in the azimuth direction, so that the card 200 can effectively communicate in such an environment.

FIG. 8 is a diagram showing the configuration of the wireless LAN card 300 of the third embodiment. In the card 300, the slot 43 extends across the top surface and one side surface of the case 1b.
Is formed. The distribution of the slot area to the upper surface and the side surface is about the same. As an effect of this configuration, radio waves can be radiated uniformly in the azimuth direction and the upward direction (zenith direction). When a base station (access point) of the wireless LAN system is installed in the zenith direction with respect to the card 300 such as an indoor ceiling, effective communication can be performed.

FIG. 9 is a diagram showing the configuration of the wireless LAN card 400 of the fourth embodiment. In the card 400, a slot 44 is formed across the upper surface and the two side surfaces of the case 1b. The upper surface is in the shape of a quarter arc. Each side has a vertical shape. With this configuration, horizontally polarized waves can be emitted in the card azimuth direction. This is an effective configuration when horizontal polarization is used in wireless LAN communication.

FIG. 10 is a diagram showing the configuration of the wireless LAN card 500 of the fifth embodiment. In the card 500, a U-shaped slot 45 is formed on the upper surface of the case 1b. With this configuration, the area occupied by the slot 45 in the antenna section b can be gathered more narrowly, and the entire wireless LAN card can be made smaller.

FIG. 11 is a diagram showing the configuration of the wireless LAN card 600 of the sixth embodiment. In the card 600, an alphabetical I-shaped slot 46 is formed on the upper surface of the case 1b, and the two slots 46 are arranged with their directions shifted by 90 degrees. According to this configuration,
Since the polarizations of the two slot antennas are offset by 90 degrees,
Polarization diversity can be performed. In the wireless LAN system, the direction of polarization of radio waves coming from above is
This configuration is effective because the direction is not fixed when viewed from the wireless LAN card.

FIG. 12 is a diagram showing the configuration of the wireless LAN card 700 of the seventh embodiment. In the card 700, the slot 47 is formed centering on the side surface and extending over the two side surfaces and the upper surface of the case 1b. In addition, slot 4
Since the direction of 7 is the horizontal direction and the vertical direction on the side surface of the card and the two directions (shifted by 90 degrees) on the upper surface of the card, it is possible to cope with various arrival directions of radio waves and polarization directions. . This configuration is very effective in a system such as a wireless LAN system in which the angle of arrival of radio waves and the polarization direction change depending on the installation direction of the wireless LAN card.

FIG. 13 is a diagram showing the structure of the wireless LAN card 800 of the eighth embodiment. In the card 800, the case 1 is formed such that the thickness of the antenna portion b is thicker than the thickness of the circuit portion a. According to this configuration, the antenna part b
Acts as a cavity and can widen the frequency band of the slot antenna.

The embodiments of the present invention have been described above. The above-described embodiment shows an example of a preferred embodiment of the present invention, and the present invention is not limited thereto, and various modifications can be made without departing from the scope of the invention. .

[0047]

As is apparent from the above description, according to the present invention, the slot antenna is constructed by directly providing the slot on the case surface. Moreover, the plastic resin case (cover) for the antenna part, which was required in the conventional wireless LAN card, is not required, and the integrated metal case for the circuit part and the antenna part is sufficient. Also, the rigidity can be increased and the card can be made compact.

Further, since there is no slot when viewed from the back of the card, the antenna gain to the back of the card is small, and radio waves can be efficiently radiated in the azimuth direction and the zenith direction of the card. Furthermore, since there is little radiation to the back of the card, it is less likely to be affected by the desk under the card, antenna characteristics,
In particular, the return loss characteristic can be stabilized.

Since the block for preventing radio wave interference is provided, the antenna characteristics can be stably maintained between the circuit portion / antenna portion and the slot antenna.

Further, by constructing the wireless LAN card in various slot forming positions and shapes, it is possible to provide a wireless LAN card according to the characteristics of the wireless LAN system.

[Brief description of drawings]

FIG. 1 is a wireless LAN according to a first embodiment of the present invention.
3 is an external perspective view of the card 100. FIG.

FIG. 2 is a wireless LAN according to the first embodiment of the present invention.
3 is an internal configuration diagram of an antenna section b of the card 100. FIG.

FIG. 3 is a view of the wireless LAN card 100 as seen from above.

FIG. 4 is an assembly diagram of the printed circuit board 2 and the block 6;

FIG. 5 is an exploded view of a printed circuit board 2 and a block 6.

FIG. 6 is a slot antenna 5 of the wireless LAN card 100.
FIG. 8 is a comparison diagram of electromagnetic wave radiation patterns of a conventional slot antenna and a conventional slot antenna.

FIG. 7 is a wireless LAN card 2 according to the second embodiment.
It is a block diagram of 00.

FIG. 8 is a wireless LAN card 3 according to the third embodiment.
It is a block diagram of 00.

FIG. 9 is a wireless LAN card 4 according to the fourth embodiment.
It is a block diagram of 00.

FIG. 10 is a configuration diagram of a wireless LAN card 500 according to a fifth embodiment.

FIG. 11 is a configuration diagram of a wireless LAN card 600 according to a sixth embodiment.

FIG. 12 is a configuration diagram of a wireless LAN card 700 according to a seventh embodiment.

FIG. 13 is a configuration diagram of a wireless LAN card 800 according to an eighth embodiment.

FIG. 14 is a diagram showing a configuration example of a conventional wireless LAN card.

[Explanation of symbols]

100-800 wireless LAN card a Circuit part b Antenna section 1 case (metal, integrated type) 2 printed circuit boards 3 microstrip lines 4, 42-47 slots 5 slot antenna 6 blocks (T shape) 61 blocks (a part between the circuit part a and the antenna part b) 62 blocks (portion between slot antennas 5) 7 stubs 8 seals

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5J021 AA02 AA12 AB05 CA01 CA04                       GA03 GA08 HA06 HA10 JA05                 5J045 AA01 AA05 AA12 AB06 CA01                       DA06 DA07 EA04 GA04 HA03                       JA11 NA01                 5J046 AA04 AA09 AA19 AB08 UA02                       UA03                 5J047 AA04 AA09 AA19 AB08 AB10                       EF04

Claims (13)

[Claims] 1. A slot antenna formed by feeding power from a microstrip line provided on a printed circuit board to a slot provided on a metal case surface. 2. A circuit part and an antenna part are covered by an integrated metal case to form a card outer shape, and the card part is provided on a surface of the case on the antenna part side from a microstrip line provided on the printed circuit board. A slot antenna is formed by feeding power to the slot, the circuit section and the antenna section are separated by a block for preventing radio wave interference in the case, and the slot is sealed with a seal. LAN card. 3. The wireless LAN card according to claim 2, wherein two of the slot antennas are formed in the antenna section. 4. The wireless LAN card according to claim 3, wherein a block for preventing radio wave interference is formed at a boundary between the two slot antennas. 5. The wireless LAN card according to claim 2, wherein the slot is provided in an L shape on the upper surface (front surface) of the case. 6. The wireless LAN card according to claim 2, wherein the slot is horizontally provided on a side surface of the case. 7. The wireless LAN according to claim 2, wherein the slot is horizontally provided on a side surface over the upper surface and one side surface of the case.
card. 8. The wireless LAN according to claim 2, wherein the slot is provided in a vertical direction on a side surface over the upper surface and two side surfaces of the case.
card. 9. The wireless LAN card according to claim 2, wherein the slot is provided in a U shape on the upper surface of the case. 10. The wireless LAN card according to claim 3, wherein the two slots are provided at right angles to each other on the upper surface of the case to enable polarization diversity. 11. The wireless device according to claim 2, wherein the slot has a slot end formed on the upper surface at the center of the side surface across the upper surface and the two side surfaces of the case. LAN card. 12. The wireless LAN card according to claim 2, wherein the thickness of the circuit portion of the case and the thickness of the antenna portion are the same. 13. The antenna part side of the case is formed thicker than the circuit part side, and a distance between the slot and the microstrip line is set to a predetermined distance for resonance. 11. The wireless LAN card according to any one of 11 above.