JP7409961B2 - antenna device - Google Patents

Description

The present invention relates to an antenna device.

Patent Document 1 below describes an antenna section for DSRC (Dedicated Short Communication) consisting of a substantially rectangular patch antenna element, and an antenna section for GPS (Global Positioning System) consisting of an inverted F antenna element extending along the outer periphery of the antenna section. An antenna device including an antenna section is disclosed.

JP2017-063255A

However, since the technology of Patent Document 1 includes two antenna elements provided separately from each other, it is difficult to suppress an increase in the number of parts and an increase in the size of the device due to multiband antennas.

An antenna device according to an embodiment includes a circuit board, an antenna element disposed on the circuit board, and a power feeding section provided on the circuit board and feeding power to the antenna element, and the antenna element is located on one side of the circuit board. The antenna electrode pattern has a substantially rectangular shape in which a first corner and a second corner located on a diagonal line are notched. The antenna element has radiation characteristics corresponding to the first frequency band in the entire area of the antenna electrode pattern, and forms a third corner of the antenna electrode pattern. A part of the L-shaped region extending along two sides thereof has radiation characteristics corresponding to the second frequency band.

According to one embodiment, it is possible to suppress an increase in the number of parts and an increase in the size of the device due to multi-band antennas.

External perspective view of an antenna device according to an embodiment A cross-sectional view of an antenna device according to an embodiment A plan view of a circuit board according to an embodiment Partially enlarged view of the circuit board shown in Figure 3 A diagram showing dimensions of each part of an antenna device in one embodiment A diagram showing dimensions of each part of an antenna device in one embodiment A diagram showing VSWR obtained by an antenna device in one example

Hereinafter, one embodiment will be described with reference to the drawings. In the following description, for convenience, the Z-axis direction is referred to as the up-down direction, the X-axis direction is referred to as the front-rear direction, and the Y-axis direction is referred to as the left-right direction.

FIG. 1 is an external perspective view of an antenna device 100 according to an embodiment. Antenna device 100 shown in FIG. 1 is a device that is installed inside a vehicle such as an automobile to enable wireless communication with the outside of the vehicle.

As shown in FIG. 1, the antenna device 100 includes a housing 110. The housing 110 has a thin rectangular parallelepiped shape that is relatively thin in the vertical direction (Z-axis direction). The housing 110 has a top plate portion 110B, a bottom plate portion 110C, and four side wall portions 110D1 to 110D4. The housing 110 has an internal space 110A surrounded by a top plate part 110B, a bottom plate part 110C, and four side walls 110D1 to 110D4. The housing 110 accommodates a circuit board 120 in an internal space 110A. For example, the housing 110 is formed using a resin material. Note that in FIG. 1, the casing 110 is shown transparent.

Further, the antenna device 100 includes a circuit board 120. The circuit board 120 is housed in the internal space 110A of the housing 110. The circuit board 120 is a flat and rectangular member. As the circuit board 120, for example, a PWB (Printed Wiring Board) is used. A ground electrode 121 and an antenna element 130 are provided on the upper surface 120A of the circuit board 120.

FIG. 2 is a cross-sectional view of the antenna device 100 according to one embodiment. As shown in FIG. 2, circuit board 120 has an upper surface 120A and a lower surface 120B. The upper surface 120A is a surface facing the top plate portion 110B of the housing 110. The lower surface 120B is a surface facing the bottom plate portion 110C of the housing 110.

As shown in FIG. 2, an antenna element 130, a ground electrode 121, a communication circuit 122, and a power feeding section 123 are provided on the top surface 120A.

The antenna element 130 has a first frequency band (5.1 to 5.7 GHz band) that is a Wi-Fi (registered trademark) frequency band, and a second frequency band that is a Wi-Fi (registered trademark) frequency band. It has frequency characteristics for each of the frequency band (2.4 to 2.5 GHz band) and the third frequency band (1575 GHz band) which is the frequency band of GNSS (Global Navigation Satellite System). That is, the antenna device 100 according to one embodiment can perform wireless communication using each of the three frequency bands.

The communication circuit 122 is provided at the center of the top surface 120A. The communication circuit 122 performs wireless communication with the outside via the antenna element 130. The communication circuit 122 can perform wireless communication with the outside via the antenna element 130 for each of the three frequency bands. For example, the communication circuit can perform satellite positioning using the third frequency band (1575 GHz band). Further, for example, the communication circuit performs short-range wireless communication using the second frequency band (2.4 to 2.5 GHz band) and the first frequency band (5.1 to 5.7 GHz band). be able to. Furthermore, the communication circuit 122 can also perform road-to-vehicle communication (V2I (Vehicle to Infrastructure), etc.), vehicle-to-vehicle communication (V2V (Vehicle to Vehicle), etc.), mobile communication (LTE (Long Term Evolution), etc.), etc. can.

The ground electrode 121 is provided around the communication circuit 122 on the upper surface 120A. Power feeding section 123 is provided between ground electrode 121 and antenna element 130. The power feeding section 123 is a portion through which power is fed to the antenna element 130.

As shown in FIG. 2, a ground electrode 124 is provided on the lower surface 120B.

Here, the first frequency band (5.1 to 5.7 GHz band) and the second frequency band (2.4 to 2.5 GHz band) are frequency bands for short-range wireless communication. Further, the third frequency band (1575 GHz band) is a frequency band for satellite positioning.

As shown in FIG. 2, the directivity of the antenna element 130 corresponding to the first frequency band (5.1 to 5.7 GHz band) and the second frequency band (2.4 to 2.5 GHz band) is It is directed toward the resin bottom plate portion 110C of the body 110. Further, the directivity of the antenna element 130 corresponding to the third frequency band (1575 GHz band) is directed toward the resin top plate portion 110B of the housing 110.

As shown in FIG. 2, the housing 110 is attached to the lower side of the roof 10 of the vehicle such that the top plate 110B faces the roof 10 of the vehicle and the bottom plate 110C faces the passenger compartment of the vehicle. It will be done. As a result, the directivity of the antenna element 130 corresponding to the first frequency band (5.1 to 5.7 GHz band) and the second frequency band (2.4 to 2.5 GHz band) is directed toward the outside of the vehicle. . Furthermore, the directivity of the antenna element 130 corresponding to the third frequency band (1575 GHz band) is directed toward the vehicle interior.

Note that, as shown in FIG. 2, on the lower surface 120B of the circuit board 120, the ground electrode 124 is formed at a position avoiding the antenna element 130. Thereby, the antenna device 100 according to one embodiment can suppress the influence of the ground electrode 124 on the radio wave radiation characteristics of the antenna element 130 toward the vehicle interior.

Further, in the antenna device 100 according to one embodiment, the top plate portion 110B and the bottom plate portion 110C of the housing 110 are made of resin. As a result, the antenna device 100 according to the embodiment can reduce the influence of the top plate part 110B and the bottom plate part 110C on the radio wave radiation characteristics of the antenna element 130 to the outside of the vehicle, and the influence of the radio waves of the antenna element 130 to the vehicle interior side. It is possible to suppress the influence on the radiation characteristics.

FIG. 3 is a top view of circuit board 120 according to one embodiment. As shown in FIG. 3, a ground electrode 121 and an antenna element 130 are formed on the upper surface 120A of the circuit board 120. The antenna element 130 and the ground electrode 121 are formed using a thin film conductor (for example, copper foil).

As shown in FIG. 3, a rectangular antenna placement area 120C having a predetermined size is provided at the left (Y-axis negative side) and front (X-axis positive side) corners of the upper surface 120A of the circuit board 120. It is being The antenna placement area 120C is an area where the antenna element 130 is installed.

The ground electrode 121 is formed over substantially the entire upper surface 120A of the circuit board 120. The ground electrode 121 has a substantially rectangular shape whose longitudinal direction is the front-rear direction (X-axis direction). At the left (Y-axis negative side) and front (X-axis positive side) corners of the ground electrode 121, there is a notch 121A formed by cutting out a rectangular portion that overlaps with the antenna placement area 120C. It is provided. The notch 121A has an L-shape with a first edge 121Aa extending linearly in the front-rear direction and a second edge 121Ab extending linearly in the left-right direction.

FIG. 4 is a partially enlarged view of the circuit board 120 shown in FIG. 3. As shown in FIG. 4, the antenna element 130 has an antenna electrode pattern 131 and a stub 132 with one end open.

As shown in FIG. 4, the antenna electrode pattern 131 has a generally rectangular shape whose longitudinal direction is the left-right direction (Y-axis direction). In the antenna electrode pattern 131, a first corner 131A1 and a second corner 131A2 located diagonally are cut out diagonally.

Further, as shown in FIG. 4, the antenna electrode pattern 131 is arranged at the fourth corner on the right side (Y-axis positive side) of the third corner 131A3 and the fourth corner 131A4 located diagonally. 131A4 is cut out diagonally.

Further, as shown in FIG. 4, the position near the third corner 131A3 on the right side 131C1 (side on the Y-axis positive side) of the antenna electrode pattern 131 and the first edge of the notch 121A of the ground electrode 121 A power feeding section 123 is provided between the section 121Aa and the section 121Aa.

Moreover, as shown in FIG. 4, the stub 132 extends along the outer periphery of the antenna electrode pattern 131 from near the third corner 131A3 of the antenna electrode pattern 131.

Specifically, the stub 132 has a first straight section 132A, a second straight section 132B, and a third straight section 132C. The stub 132 has an L-shape formed by a second straight portion 132B and a third straight portion 132C.

The first straight portion 132A extends linearly rearward (in the negative X-axis direction) from a position near the third corner 131A3 on the rear side 131C2 (the negative side on the X-axis) of the antenna electrode pattern 131. do.

The second straight portion 132B extends from the rear end portion (X-axis negative side end) of the first straight portion 132A to the rear side 131C2 (X-axis negative side) of the antenna electrode pattern 131 and the ground electrode. 121, along the rear side 131C2 (X-axis negative side) of the antenna electrode pattern 131, in a straight line in the left direction (Y-axis negative direction). It is a band-shaped part that extends to

The third linear portion 132C extends from the left end (the end on the Y-axis negative side) of the second linear portion 132B to the front ( This is a band-shaped portion that extends linearly in the positive direction of the X-axis.

As shown in FIG. 4, the antenna element 130 is provided in the antenna arrangement area 120C on the top surface 120A of the circuit board 120 such that the open end of the stub 132 is closer to the outer periphery of the circuit board 120 than the feeding section 123. .

The antenna element 130 has radiation characteristics corresponding to the first frequency band (5.1 to 5.7 GHz band) in the entire area of the antenna electrode pattern 131.

Moreover, the antenna element 130 has a second frequency band ( It has radiation characteristics corresponding to the 2.4 to 2.5 GHz band).

Furthermore, the antenna element 130 has radiation characteristics corresponding to the third frequency band (1575 GHz band) in a region including the antenna electrode pattern 131 and the stub 132.

〔Example〕
An example of the antenna device 100 according to one embodiment will be described below with reference to FIGS. 5 to 7.

5 and 6 are diagrams showing the dimensions of each part of the antenna device 100 in one embodiment. As shown in FIGS. 5 and 6, the dimensions of each part of the antenna device 100 used in this example are as follows.

- External dimensions of the housing 110: 140 mm x 112 mm x 29 mm (length x width x height)
- External dimensions of circuit board 120: 132 mm x 102 mm x 1.3 mm (length x width x thickness)
・External dimensions of antenna placement area 120C: 26mm x 24.6mm (width x length)
- External dimensions of antenna electrode pattern 131: 22 mm x 12 mm (width x length)
- External dimensions of stub 132: 24 mm x 15 mm (width x length)

FIG. 7 is a diagram showing VSWR (Voltage Standing Wave Ratio) obtained by the antenna device 100 in one embodiment.

As shown in FIG. 7, in this example, the antenna device 100 according to one embodiment achieves a VSWR of "1.86 to 2.59" in the third frequency band (1575 GHz band), which is the GNSS frequency band. was gotten.

Further, as shown in FIG. 7, in this example, the antenna device 100 according to one embodiment achieves VSWR in the second frequency band (2.4 to 2.5 GHz band) that is the Wi-Fi frequency band. "2.47 to 2.63" was obtained.

Further, as shown in FIG. 7, in this example, the antenna device 100 according to one embodiment has a VSWR in the first frequency band (5.1 to 5.7 GHz band) that is the Wi-Fi frequency band. "1.75 to 2.62" was obtained.

That is, according to this example, the antenna device 100 according to one embodiment was able to obtain a VSWR of less than the target value "3.0" in any of the three frequency bands.

As described above, the antenna device 100 according to one embodiment includes a circuit board 120, an antenna element 130 arranged on the circuit board 120, and a power feeding section 123 provided on the circuit board 120 and feeding power to the antenna element 130. The antenna element 130 is provided on the upper surface 120A of the circuit board 120, and has a substantially rectangular shape with a first corner 131A1 and a second corner 131A2 located diagonally cut out. The feeding part 123 has an electrode pattern 131, the feeding part 123 is provided near the third corner 131A3 of the antenna electrode pattern 131, and the antenna element 130 has a first frequency band in the entire area of the antenna electrode pattern 131. (5.1 to 5.7 GHz band), and has an L-shape extending along the two sides forming the third corner 131A3 of the antenna electrode pattern 131. The region 131B has radiation characteristics corresponding to the second frequency band (2.4 to 2.5 GHz band).

Thereby, the antenna device 100 according to one embodiment can perform wireless communication using two different frequency bands using the single antenna element 130. Therefore, according to the antenna device 100 according to one embodiment, it is possible to suppress an increase in the number of parts and an increase in the size of the device due to multi-band antennas.

Furthermore, in the antenna device 100 according to one embodiment, the antenna element 130 is a one-end open type that extends from the vicinity of the third corner 131A3 of the antenna electrode pattern 131 along the outer periphery of the antenna electrode pattern 131. It further includes a stub 132, and has radiation characteristics corresponding to the third frequency band (1575 GHz band) in a region including the antenna electrode pattern 131 and the stub 132.

Thereby, the antenna device 100 according to one embodiment can perform wireless communication using three different frequency bands using the single antenna element 130. Therefore, according to the antenna device 100 according to one embodiment, it is possible to suppress an increase in the number of parts and an increase in the size of the device due to multi-band antennas.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to these embodiments, and various modifications or variations can be made within the scope of the gist of the present invention as described in the claims. Changes are possible.

100 Antenna device 110 Housing 110B Top plate part 110C Bottom plate part 110D1 to 110D4 Side wall part 120 Circuit board 120A Top surface 120B Bottom surface 120C Antenna arrangement area 121 Ground electrode 121A Notch part 122 Communication circuit 123 Power feeding part 130 Antenna element 131 Electrode pattern for antenna 131A1 First corner 131A2 Second corner 131A3 Third corner 131A4 Fourth corner 132 Stub 132A First straight section 132B Second straight section 132C Third straight section

Claims (7)

a circuit board;
An antenna element arranged on a circuit board,
a power feeding unit provided on the circuit board and feeding power to the antenna element;
The antenna element is
an antenna electrode pattern provided on one surface of the circuit board and having a substantially rectangular shape with first and second corners located diagonally cut out;
The power feeding section is
provided near the third corner of the antenna electrode pattern,
The antenna element is
The entire area of the antenna electrode pattern has radiation characteristics corresponding to a first frequency band,
In the antenna electrode pattern, a part of the L-shaped region extending along the two sides forming the third corner has radiation characteristics corresponding to the second frequency band. Characteristic antenna device. The antenna element is
further comprising an open-ended stub extending along the outer periphery of the antenna electrode pattern from near the third corner of the antenna electrode pattern,
The antenna device according to claim 1, wherein a region including the antenna electrode pattern and the stub has radiation characteristics corresponding to a third frequency band. The antenna element is
provided in an antenna arrangement area at a corner of the circuit board such that the open end of the stub is closer to the outer periphery of the circuit board than the power feeding section;
The antenna device according to claim 2, further comprising a ground electrode on the other surface of the circuit board at a position away from the antenna arrangement area. further comprising a casing that accommodates the circuit board,
Claim characterized in that the casing has a top plate made of resin that faces the one surface of the circuit board, and a bottom plate made of resin that faces the other surface of the circuit board. 3. The antenna device according to 3. The first frequency band and the second frequency band are frequency bands for short-range wireless communication,
The third frequency band is a frequency band for satellite positioning,
Directivity of the antenna element corresponding to the first frequency band and the second frequency band is directed toward the bottom plate side of the housing,
The directivity of the antenna element corresponding to the third frequency band is directed toward the top plate portion of the housing.
The antenna device according to claim 4, characterized in that: The casing is attached to the lower side of the roof of the vehicle such that the top plate portion faces the roof side of the vehicle and the bottom plate portion faces the passenger compartment side of the vehicle. The antenna device according to claim 5. The circuit board includes:
It is characterized by comprising a communication circuit capable of performing the short-range wireless communication using the first frequency band and the second frequency band, and the satellite positioning using the third frequency band. The antenna device according to claim 6.

Images