Patent Application
20240136717
The present disclosure relates to a patch antenna.
PTL 1 discloses a patch antenna including a ground conductor plate, a dielectric substrate, and a radiating element.
[PTL 1] Japanese Patent Application Publication No. 2014-160902
When an antenna device housing a patch antenna is reduced in size, the area of a base functioning as a ground for the patch antenna becomes small, which may lower the gain of the patch antenna at low elevation angles.
An example object of the present invention is to improve the gain of a patch antenna at low elevation angles. Other objects of the present invention should become apparent from the descriptions herein.
An aspect of the present disclosure is a patch antenna comprising: a radiating element; a first dielectric member at which the radiating element is provided; and at least one second dielectric member provided around the first dielectric member.
According to an aspect of the present invention, the gain of a patch antenna at low elevation angles improves.
At least the following points become apparent from the descriptions herein and the drawings attached hereto.
The vehicular antenna device 10 is housed in a void 4 between a roof panel 2 of the vehicle 1 and a roof lining 3 of a ceiling surface of a vehicle interior. The roof panel 2 is formed of, for example, an insulating resin so that the vehicular antenna device 10 can receive electromagnetic waves (hereinafter referred to as “radio waves” where appropriate).
The vehicular antenna device 10 housed in the void 4 is secured to the roof lining 3, which is formed of an insulating resin, with screws or the like. The vehicular antenna device 10 is thus surrounded by the roof panel 2 and the roof lining 3 that are insulating. Although the vehicular antenna device 10 is secured to the roof lining 3 in the present embodiment, the vehicular antenna device 10 may be secured to, for example, a vehicle frame or the resinous roof panel 2.
Also, because the actual void 4 is limited in space, it is difficult to increase the area of a ground plate functioning as a ground for the vehicular antenna device 10. For this reason, when a typical patch antenna is provided in a vehicular antenna device, the gain at low elevation angles may lower. In the present embodiment below, the vehicular antenna device 10 including a patch antenna that can improve its gain at low elevation angles is described.
The base 11 is a quadrilateral metal plate used as a common ground by the antennas 21 to 26 and the patch antenna 30 and is placed on the roof lining 3, inside the void 4. Also, the base 11 is a thin plate extending to the front, rear, left, and right.
The case 12 is a box-shaped member, and out of its six faces, the lower face is open. Also, the case 12 is formed of an insulating resin, and for this reason, radio waves may pass through the case 12. Then, the case 12 is attached to the base 11 in such a manner that the opening of the case 12 may be closed by the base 11. Thus, the antennas 21 to 26 and the patch antenna 30 are housed in the internal space of the case 12.
The antennas 21 to 26 and the patch antenna 30 are mounted on the base 11, inside the case 12. The patch antenna 30 is disposed at a position near the center of the base 11, and the antennas 21 to 26 are disposed around the patch antenna 30. Specifically, the antennas 21, 22 are disposed at the front side and the rear side of the patch antenna 30, respectively. Also, the antennas 23, 24 are disposed at the left side and the right side of the patch antenna 30, respectively. Further, the antenna 25 is disposed at the left side of the antenna 22 and the rear side of the antenna 23, and the antenna 26 is disposed at the right side of the antenna 21 and the front side of the antenna 24.
The antenna 21 is, for example, a flat antenna used for the GNSS (Global Navigation Satellite System) and receives radio waves in the 1.5-GHz band from satellites.
The antenna 22 is, for example, a monopole antenna used for the V2X (Vehicle-to-everything) system and transmits and receives radio waves in the 5.8-GHz band or the 5.9-GHz band. Although the antenna 22 is an antenna for V2X here, the antenna 22 may be an antenna for, for example, Wi-Fi or Bluetooth.
The antennas 23, 24 are telematics antennas and are antennas used for, for example, LTE (Long Term Evolution) and the fifth-generation mobile communication system. The antennas 23, 24 transmit and receive radio waves from the 700-MHz frequency band to the 2.7-GHz band defined by the LTE standards. Further, the antennas 23, 24 also transmit and receives radio waves in the Sub-6 band defined by the fifth-generation mobile communication system standards, i.e., radio waves from the 3.6-GHz band to frequencies under 6 GHz.
The antennas 25, 26 are telematics antennas and are antennas used for, for example, the fifth-generation mobile communication system. The antennas 25, 26 transmit and receive radio waves in the Sub-6 band defined by the fifth-generation mobile communication system standards.
The communication standards and frequency bands that can be applied to the antennas 21 to 26 are not limited to the ones described above, and other communication standards and frequency bands may be used.
The patch antenna 30 is an antenna used for, for example, SDARS (Satellite Digital Audio Radio Service). The patch antenna 30 receives left circularly polarized waves in the 2.3-GHz band. SDARS satellites are stationary satellites. For this reason, the patch antenna 30 is required to have favorable gain at low elevation angles as well in order to receive SDARS signals particularly in service areas in Northern Canada (a high latitude region).
With reference to
The patch antenna 30 is configured including a circuit board 32 on which conductive patterns 31, 33 (to be described later) are formed, a first dielectric member 34, a radiating element 35, a second dielectric member 36, and a shield cover 50. The circuit board 32, the first dielectric member 34 and the second dielectric member 36, and the radiating element 35 stacked in this order in the positive Z-axis direction are hereinafter referred to as a “main body portion of the patch antenna 30” in the present embodiment.
The circuit board 32 is a dielectric plate member having the conductive patterns 31, 33 formed on its back surface (the surface in the negative Z-axis direction) and its front surface (the surface in the positive Z-axis direction), respectively, and is made of, for example, glass epoxy resin. The conductive pattern 31 includes a circuit pattern 31a and a ground pattern 31b.
The circuit pattern 31a is a conductive pattern to which, for example, a signal line 45a of a coaxial cable 45 from an amplifier board (not shown) is connected. Also, a braid 45b of the coaxial cable 45 is electrically connected to a ground pattern 31b with solder (not shown). A description will be given later about the configuration for connecting the circuit pattern 31a and the radiating element 35.
The ground pattern 31b is a conductive pattern for electrically connecting the main body portion of the patch antenna 30 to the metallic base 11. The ground pattern 31b and four seat portions 11a provided at the metallic base 11 are electrically connected to each other. Each of the four seat portions 11a here is formed by bending a part of the base 11 to be able to support the main body portion of the patch antenna 30. By the electrical connecting between the ground pattern 31b and the seat portions 11a, the ground pattern 31b is electrically connected to the metallic base 11. The back surface of the circuit board 32 has, for example, the metallic shield cover 50 attached thereto to protect the circuit pattern 31a.
The conductive pattern 33 formed on the front surface of the circuit board 32 is a ground pattern functioning as a ground for a ground conductor plate (or a ground conductor film) of the patch antenna 30 and a circuit (not shown). The conductive pattern 33 is electrically connected to the ground pattern 31b via a through-hole. Also, the ground pattern 31b is electrically connected to the base 11 via the seat portions 11a and securing screws for securing the circuit board 32 to the seat portions 11a. The conductive pattern 33 is thus electrically connected to the base 11.
The first dielectric member 34 is a substantially quadrilateral plate-shaped member having sides parallel to the X-axis and sides parallel to the Y-axis. The front surface and the back surface of the first dielectric member 34 are parallel to the X-axis and the Y-axis, with the front surface of the first dielectric member 34 facing in the positive Z-axis direction and the back surface of the first dielectric member 34 facing in the negative Z-axis direction. Then, the back surface of the first dielectric member 34 is attached to the conductive pattern 33 with, for example, a double-sided tape. The first dielectric member 34 is formed of a dielectric material such as ceramics. Also, the first dielectric member 34 has sides 34a, 34c parallel to the Y-axis and sides 34b, 34d parallel to the X-axis.
The radiating element 35 is a substantially quadrilateral conductive element having a smaller area than the front surface of the first dielectric member 34 and is formed on the front surface of the first dielectric member 34. In the present embodiment, the direction normal to the radiation surface of the radiating element 35 is the positive Z-axis direction.
A term “substantially quadrilateral” used herein refers to a shape made up of four sides, such as, for example, a square and a rectangle, and for example, at least some of its angles may be cut away obliquely relative to the sides. Also, a “substantially quadrilateral” shape may be provided with a notch (a concave portion) or a protrusion (a convex portion) at part of its sides. In other words, a “substantially quadrilateral shape” may be any shape that allows the radiating element 35 to transmit and receive radio waves of desired frequencies.
The second dielectric member 36 is a dielectric member provided around the first dielectric member 34. As with the first dielectric member 34, the front surface and the back surface of the second dielectric member 36 are parallel to the X-axis and the Y-axis, with the front surface of the second dielectric member 36 facing in the positive Z-axis direction and the back surface of the second dielectric member 36 facing in the negative Z-axis direction. Then, as with the first dielectric member 34, the back surface of the second dielectric member 36 is attached to the conductive pattern 33 with, for example, a double-sided tape.
As shown in
Note that the second dielectric member 36 is formed of a dielectric material such as ceramics. The second dielectric member 36 may be formed of the same dielectric material as the first dielectric member 34 or may be formed of a different dielectric material from the first dielectric member 34.
A through-hole 41 penetrates the circuit board 32, the conductive pattern 33, and the first dielectric member 34. Inside the through-hole 41, a feed line 42 connecting the circuit pattern 31a and the radiating element 35 is provided. Note that the feed line 42 connects the circuit pattern 31a to the radiating element 35 while providing electrical insulation from the grounded conductive pattern 33. Also, in the present embodiment, a point where the feed line 42 is electrically connected to the radiating element 35 is referred to as a feed point 43a.
Note that the “center point 35p of the radiating element 35” refers to the center of the shape of the outer edge of the radiating element 35, i.e., the geometric center thereof. The radiating element 35 of single-feed type in
Although
The upper part of
As described above, the second dielectric member 36 functions to provide stronger radio wave radiation at low elevation angles, and the radiating element 35 receives left circularly polarized waves in the 2.3 GHz band. Thus, the radio waves received by the radiating element 35 are affected by changes in the installation mode and size of the second dielectric member 36. For this reason, first, installation conditions for the second dielectric member 36 are described with reference to
In the present embodiment, a dielectric material used for the second dielectric member 36 has a relative dielectric constant εr2 larger than a relative dielectric constant εr1 of the first dielectric member 34 (εr2>εr1). Specifically, a dielectric material with a relative dielectric constant εr1 of 7.82 is used for the first dielectric member 34, and a dielectric material with a relative dielectric constant εr2 of is used for the second dielectric member 36. However, as will be described later, a dielectric material used for the second dielectric member 36 may have a relative dielectric constant εr2 equal to or smaller than the relative dielectric constant εr1 of the first dielectric member 34 (εr2≤εr1).
As shown in
A “thickness T” is, for example, a dimension in the vertical direction (the Z-direction) of a target. For example, in
The gain of the patch antenna 30 and the gain of the patch antenna 30X of the comparative example were calculated under predetermined conditions (hereinafter referred to as “simulation conditions 1”), such as the size of the radiating element 35, the relative dielectric constant εr1 and size of the first dielectric member 34, the relative dielectric constant εr2 and size of the second dielectric member 36, the size of the base 11, the size of the circuit board 32, and the feed type. For the simulation of the patch antenna 30 and the patch antenna 30X, models without the circuit pattern 31a and the like are used for the sake of convenience because they do not affect the gain much.
As thus described, when the second dielectric member 36 is provided around the first dielectric member 34, the gain of the patch antenna 30 at low elevation angles improves. As a result, the patch antenna 30 can receive radio waves arriving at low elevation angles efficiently.
Here, a description about changing the installation conditions for the second dielectric member 36 is given. Note that two or more of the conditions described below may be changed and used in combination.
==Changing the Relative Dielectric Constant εr2==
First, the characteristics that the patch antenna 30 exhibits when the relative dielectric constant εr2 is changed among the installation conditions for the second dielectric member 36 are examined. Note that the conditions for the patch antenna 30 other than the relative dielectric constant εr2 (such as, for example, the physical sizes of the main components of the patch antenna 30, the feed type, the relative dielectric constant εr1 of the first dielectric member 34) and the like are the same as the simulation conditions 1 described earlier.
The patch antenna 30 employing the second dielectric member 36 with a relative dielectric constant εr2 of 30 has higher average gain at the low elevation angles of 20° to 30° than the patch antenna 30X of the comparative example, as with the case of using the second dielectric member 36 with a relative dielectric constant εr2 of 20. As shown in
Although cases where the relative dielectric constant εr2 of the second dielectric member 36 is larger than the relative dielectric constant εr1 of the first dielectric member 34 (εr2>εr1) are examined above, as shown in
Thus, in order for the second dielectric member 36 to contribute to improvement in the gain at low elevation angles, it is preferable that the relative dielectric constant Erg of the second dielectric member 36 be larger than the relative dielectric constant εr1 of the first dielectric member 34. In this case, the relative dielectric constant Erg of the second dielectric member 36 is preferably 30 or larger or more preferably 35 or larger. Also, it is even more preferable that the relative dielectric constant εr2 of the second dielectric member 36 be 40 or larger.
In the patch antenna 30 under the simulation conditions 1, the thickness T of the first dielectric member 34 is 6 mm, and the thickness T of the second dielectric member 36 is also 6 mm. Thus, the thickness T of the first dielectric member 34 is the same as the thickness T of the second dielectric member 36. However, the thickness T of the second dielectric member 36 may be changed.
As with the patch antenna 30 in which the thickness T of the second dielectric member 36 is set to 6 mm, the patch antenna 30 in which the thickness T of the second dielectric member 36 is set to 5 mm or 3 mm (
Also, as with the patch antenna 30 in which the thickness T of the second dielectric member 36 is set to 6 mm, the patch antenna 30 in which the thickness T of the second dielectric member 36 is set to 7 mm or 8 mm (
Thus, in order to reduce the sizes of the antenna device and the patch antenna and further improve the gain at low elevation angles while keeping the manufacturing costs down, it is preferable that the thickness T of the second dielectric member 36 be substantially the same as or smaller than the thickness T of the first dielectric member 34.
Although in the patch antennas 30 examined above, a single second dielectric member 36 is formed in such a shape as to surround the first dielectric member 34, the present invention is not limited to this. A plurality of second dielectric members may be provided around the first dielectric member 34.
In a plan view of the front surface of the radiating element 35 seen in the positive Z-axis direction, the “width W” of the second dielectric member 39 as an example of the second dielectric members 37 to 40 is, as with the patch antenna 30 shown in
In a plan view of the front surface of the radiating element 35 seen in the positive Z-axis direction, the “length D” of the second dielectric member 38 as an example of the second dielectric members 37 to 40 is a dimension of the second dielectric member 36 in a direction parallel to the outer edge (here, the side 34b) of the first dielectric member 34. In other words, the length D is a distance between one end portion of the outer edge of the first dielectric member 34 to its closest end portion in linear distance. The same definition applies to the “length D” of the second dielectric members other than the second dielectric member 38 as well. Although the lengths D of the second dielectric members 37 to 40 are all the same in the present embodiment, the present invention is not limited to this. For example, the lengths D of the second dielectric members 37 to 40 facing the respective sides of the first dielectric member 34 may be different from one another. Also, some of the lengths D of the second dielectric members 37 to 40 facing the sides of the first dielectric member 34 may be the same. Also, although the second dielectric members 37 to 40 are substantially in the shape of a quadrangle here, the present invention is not limited to this. For example, the second dielectric members 37 to 40 may be in the shape of a quadrilateral such as a square, a parallelogram, or a trapezoid or in the shape of a triangle.
As shown in
As shown in
In the example in
Also, in the example in
Note that each of the second dielectric members 37 to 40 is provided parallel to the outer edge of the first dielectric member 34. Specifically, the second dielectric member 37 is provided in parallel to the side 34a of the first dielectric member 34, the second dielectric member 38 is provided in parallel to the side 34b of the first dielectric member 34, the second dielectric member 39 is provided in parallel to the side 34c of the first dielectric member 34, and the second dielectric member 40 is provided in parallel to the side 34d of the first dielectric member 34. What is meant by the second dielectric member 40, as an example of the second dielectric members 37 to 40, being “parallel” to the side 34d of the first dielectric member 34 is that the side of the second dielectric member 40 which is closest to the first dielectric member 34 is parallel to the outer edge (here, the side 34d) of the first dielectric member 34 which faces the second dielectric member 40. The same definition applies to how the second dielectric members other than the second dielectric member 40 are parallel to the outer edge of the first dielectric member 34 as well. Also, although the second dielectric members 37 to 40 are substantially in the shape of a quadrangle here, the present invention is not limited to this. For example, the second dielectric members 37 to 40 may be in the shape of a quadrilateral such as a square, a parallelogram, or a trapezoid or in the shape of a triangle.
The gain of the patch antenna 30A and the gain of the patch antenna 30X of the comparative example were calculated below under predetermined conditions (hereinafter referred to as “simulation conditions 2”), such as the width W, the length D, the gap G, and the offset amounts OS of the second dielectric members 37 to 40. Note that various conditions and the like for the patch antenna 30A other than the simulation conditions 2 are the same as the simulation conditions 1 for the patch antenna 30 described earlier.
As with the patch antenna 30, the patch antenna 30A too has higher average gain at the low elevation angles of 20° to 30° than the patch antenna 30X. This shows that average gain at the low elevation angles of 20° to 30° is higher than that of the patch antenna 30X even when there are four second dielectric members 37 to 40 each being provided in parallel to the outer edge of the first dielectric member 34. As a result, the patch antenna 30A too can efficiently receive radio waves arriving at low elevation angles.
Here, a description about changing the installation conditions for the second dielectric members 37 to 40 is given. Note that two or more of the conditions described below may be changed and used in combination.
In the patch antenna 30A described above, four second dielectric members 37 to 40 are provided around the first dielectric member 34. Alternatively, the number of second dielectric members 37 to 40 provided around the first dielectric member 34 may be changed.
As with the patch antenna 30A, the patch antenna 30B too has higher average gain at the low elevation angles of 20° to 30° than the patch antenna 30X. This shows that the average gain at the low elevation angles of 20° to 30° is higher than that of the patch antenna 30X not only when there are four second dielectric members 37 to 40, but also when there are two second dielectric members 38, 40 each being provided in parallel to the outer edge of the first dielectric member 34. As a result, the patch antenna 30B too can efficiently receive radio waves arriving at low elevation angles.
Note that the positions at which the two second dielectric members are disposed are not limited to the case shown in
Note that although the patch antennas 30, 30A, 30B described above receive left circularly polarized waves, they may be ones that receive linearly polarized waves. In such a case, the single feed type is employed, and the feed point 41a is displaced from the center point of the radiating element 35 in the positive X-axis direction. Then, the main polarization plane is a plane defined by a straight line connecting the feed point and the center point of the radiating element 35 and by a line normal to the radiating element 35. Thus, the main polarization plane is parallel to the XZ-plane. Also, the secondary main polarization plane is a plane being orthogonal to the main polarization plane and passing through the center point of the radiating element 35. Thus, the secondary main polarization plane is parallel to the YZ-plane.
The patch antenna 30B may be one that receives linearly polarized waves described above. In that case, the second dielectric members 38, 40 are provided at such positions as to face each other with the radiating element 35 in between in a direction of a straight line connecting the feed point 43a of the radiating element 35 and the center point 35P of the shape of the radiating element 35. Also, when the patch antenna 30B receives linearly polarized waves, the main polarization plane is the XZ-plane, and the second dielectric members 38, 40 intersect with the main polarization plane. Although detailed calculation results are omitted here, the gain at low elevation angles can be improved in this case as well like in
Although a case where a plurality of second dielectric members 36 are provided around the first dielectric member 34 is examined above, the present invention is not limited to this. A single second dielectric member may be provided at part of an area around the first dielectric member 34.
As with the patch antenna 30A, the patch antenna 30C has higher average gain at the low elevation angles of 20° to 30° than the patch antenna 30X. This shows that the average gain at the low elevation angles of 20° to 30° is higher than that of the patch antenna 30X not only when a plurality of second dielectric members 37 to 40 are provided, but also when the single second dielectric member 38 is provided in parallel to the outer edge of the first dielectric member 34.
Note that the disposition and position of the single second dielectric member is not limited to the case shown in
As with the patch antenna 30 and the patch antenna 30A, average gain at the low elevation angles at 20° to 30° is higher than that of the patch antenna 30X even when the width W is changed. This shows that average gain at the low elevation angles of 20° to 30° is higher than that of the patch antenna 30X even when the width W of each of the second dielectric members 37 to 40 is not 6 mm.
As with the patch antenna 30 and the patch antenna 30A, average gain at the low elevation angles at 20° to 30° is higher than that of the patch antenna 30X even when the length D is changed. This shows that average gain at the low elevation angles of 20° to 30° is higher than that of the patch antenna 30X even when the length D of each of the second dielectric members 37 to 40 is not 28 mm.
The second dielectric members 37 to 40 are in contact with the outer edge of the first dielectric member 34 above. Alternatively, the second dielectric members 37 to 40 may be provided outwardly away from the outer edge of the first dielectric member 34.
As with the patch antenna 30A, the patch antenna 30D too has higher average gain at the low elevation angles of 20° to 30° than the patch antenna 30X. This shows that the average gain at the low elevation angles of 20° to 30° is higher than that of the patch antenna 30X even when the gap G is provided.
Although a case of changing the gap G in the patch antenna 30A in which four second dielectric members 37 to 40 are provided around the first dielectric member 34 is examined above, the present invention is not limited to this. Although detailed calculation results are omitted here, gain at low elevation angles can be improved like in
Although the X-axis-direction offset amount OS and the Y-axis-direction offset amount OS are both 0 mm in the patch antenna 30A as shown in
For example,
As is apparent from
Note that the positions of the X-axis-direction mid-points of the second dielectric members 38, 40 may be displaced from the positions of the X-axis-direction mid-points of the sides 34b, 34d of the first dielectric member 34 in a direction opposite from the direction of circling of left circularly polarized waves. Also, the positions of the Y-axis-direction mid-points of the second dielectric members 37, 39 may be displaced from the positions of the Y-axis-direction mid-points of the sides 34a, 34c of the first dielectric member 34 in a direction opposite from the direction of circling of left circularly polarized waves. Although detailed calculation results are omitted here, the gain at low elevation angles can be improved in this case as well like in
While it is possible to improve gain at low elevation angles when the offset amounts OS are set like in, for example, the patch antenna 30E, in this case, the second dielectric members 37 to 40 may protrude outward from the ranges of the sides 34a to 34d of the first dielectric member 34. Consequently, the size of the patch antenna 30E increases in such a configuration. Thus, it is preferable that the offset amounts OS be set so that the second dielectric members 37 to 40 may not be located beyond the ranges of the sides 34a to 34d. Setting the offset amounts OS this way makes it possible to reduce the space for the patch antenna.
Although the radiating element 35 and the first dielectric member 34 in the patch antenna 30 are “substantially quadrilateral,” the present invention is not limited to this. The radiating element 35 and the first dielectric member 34 may be in the shape of, for example, a circle, an ellipse, or a polygon other than the substantial quadrilateral. In a case where the radiating element 35 or the first dielectric member 34 is, for example, circular, the second dielectric member 36 may be arc-shaped, conforming to the outer edge of the radiating element 35 or the first dielectric member 34. Gain at low elevation angles can be improved also when such a radiating element or second dielectric member is used.
The patch antenna 30 of the present embodiment is provided in the vehicular antenna device 10, but the present invention is not limited to this. For example, the patch antenna 30 may be provided in a casing of a typical shark fin antenna. Also, the patch antenna 30 may be provided in an antenna device mounted to an instrument panel. In this case, the patch antenna 30 may be provided directly to, e.g., a metal plate corresponding to the base 11.
The patch antenna 30 of the present embodiment has been described above. For example, as shown in
In addition, while the relative dielectric constant Erg of the second dielectric member 36 may be equal to or smaller than the relative dielectric constant εr1 of the first dielectric member 34 (εr2≤εr1), it is desirable that the relative dielectric constant εr2 of the second dielectric member 36 be larger than the relative dielectric constant εr1 of the first dielectric member 34 (εr2>εr1). Providing the second dielectric member 36 having such a relative dielectric constant εr2 ensures to improve gain at low elevation angles.
In addition, it is desirable that the relative dielectric constant εr2 of the second dielectric member 36 be 30 or larger (εr2≥30). Providing the second dielectric member 36 having such a relative dielectric constant εr2 makes it possible to improve gain at low elevation angles even more.
In addition, it is desirable that the thickness T of the second dielectric member 36 be substantially the same as or smaller than the thickness T of the first dielectric member 34. Providing the second dielectric member 36 having such a thickness T makes it possible to reduce the sizes of the antenna device and the patch antenna while keeping manufacturing costs down.
In addition, as described above, the patch antennas 30A to 30E can improve gain at low elevation angles even in a case where the radiating element 35 receives circularly polarized waves.
In addition, in a case where the radiating element 35 receives circularly polarized waves as described above, in the patch antenna 30, the second dielectric member 36 is formed in such a shape that the first dielectric member 34 is surrounded, as shown in, for example,
In addition, in a case where the radiating element 35 receives circularly polarized waves as described above, instead of the second dielectric member 36 being formed in such a shape that the first dielectric member 34 is surrounded, a plurality of second dielectric members 37 to 40 may be provided, with each of the second dielectric members 37 to 40 being provided in parallel to the outer edge of the first dielectric member 34, like, for example, the patch antenna 30A shown in
In addition, the patch antenna 30 can improve gain at low elevation angles in a case of receiving not only circularly polarized waves, but also linearly polarized waves. For example, as shown in
Also, for example, the second dielectric members 36 to 40 of the patch antennas 30, 30A, 30B, 30C, 30E shown in
The term “vehicle-mounted” used herein means that the antenna device can be mounted on a vehicle; thus, the antenna device includes not only one which is mounted on a vehicle, but also one which is brought into a vehicle and used inside the vehicle. Also, although the antenna device of the present embodiment is used in a “vehicle” which is a wheeled means of transportation, the present invention is not limited to this, and may be used for, for example, an air vehicle such as a drone, a space probe, wheelless construction machinery, agricultural machinery, a mobile object such as a vessel.
The embodiments described above are provided to facilitate the understanding of the present invention and is not intended to limit the interpretation of the present invention. Also, it goes without saying that the present invention can be modified and improved and that the present invention includes such equivalents as well.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-027893 | Feb 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP22/07112 | 2/22/2022 | WO |
