Flat antennas and vehicle windows

Abstract

Provided is a broadband planar antenna capable of handling relatively high frequency bands up to approximately 6 GHz.　This planar antenna comprises slots formed in a flat conductor. The slots include: a first slot extending in a first direction between a first feeding point and a second feeding point; a second slot extending in a second direction different from the first direction from an end of the first slot in the first direction; a third slot extending in a fourth direction opposite to the second direction from an end of the first slot in a third direction opposite to the first direction to an open end thereof opening in the fourth direction; and a J-shaped slot extending, in a J-shape, from an end of the second slot in the second direction to an open end thereof opening in the first direction. The open end of the J-shaped slot has a slot width greater than that of the end of the second slot in the second direction.

Description

Technical Field

[0001] The present disclosure relates to a planar antenna and a vehicle window glass.

Background Art

[0002] Conventionally, as an antenna provided in a vehicle window glass, a planar slot antenna formed on a conductive film is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The slot antenna disclosed in Patent Document 1 is suitable for transmitting and receiving radio waves in a frequency band up to about 2.69 GHz. However, it has not been easy to widen the band in which impedance matching is possible to a relatively high frequency band up to about 6 GHz.

[0005] The present disclosure provides a broadband planar antenna capable of corresponding to a relatively high frequency band up to about 6 GHz and a vehicle window glass including the planar antenna.

Means for Solving the Problems

[0006] According to one aspect of the present disclosure, it includes slots formed in a flat conductor, where the slots are a first slot extending in a first direction between a first feeding point and a second feeding point, and a second slot extending in a second direction different from the first direction from an end of the first slot in the first direction, The invention includes a third slot extending from the end of the first slot in a third direction opposite to the first direction, in a fourth direction opposite to the second direction, to an open end that opens in the fourth direction, and a J-shaped slot extending in a J-shape from the end of the second slot in a second direction to an open end that opens in the first direction, A planar antenna and a vehicle window glass equipped with the planar antenna are provided, wherein the slot width at the open end of the J-shaped slot is wider than the slot width at the end of the second slot in the second direction.

[0007] In another aspect of this disclosure, It has slots formed in a flat conductor, The aforementioned slot is A first slot extending in the first direction between the first power supply point and the second power supply point, A second slot extends from the end of the first slot in the first direction in a second direction different from the first direction, The invention comprises a third slot extending from the end of the first slot in a third direction opposite to the first direction, in a fourth direction opposite to the second direction, and reaching an open end that opens in the fourth direction, and a seventh slot extending from the end of the second slot in a second direction to an open end that opens in the third direction, The slot width at the open end of the seventh slot is wider than the slot width at the end of the second slot in the second direction. A planar antenna and a vehicle window glass equipped with the planar antenna are provided, wherein the slot length of the second slot is shorter than the slot length of the first slot. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a wideband planar antenna capable of supporting relatively high frequency bands up to approximately 6 GHz, and a vehicle window glass equipped with said planar antenna. [Brief explanation of the drawing]

[0009] [Figure 1]This is a diagram showing an example of the configuration of a planar antenna according to the first embodiment in a plan view. [Figure 2] This is a diagram showing an example of the configuration of a planar antenna according to the second embodiment in a plan view. [Figure 3] This is a diagram showing an example of the configuration of a planar antenna according to the third embodiment in a plan view. [Figure 4] This is a diagram showing an example of the configuration of a planar antenna according to the fourth embodiment in a plan view. [Figure 5] This is a diagram showing an example of the configuration of a planar antenna according to the fifth embodiment in a plan view. [Figure 6] This is a diagram showing an example of the configuration of a planar antenna according to the sixth embodiment in a plan view. [Figure 7] This is a diagram showing an example of the configuration of a planar antenna according to the seventh embodiment in a plan view. [Figure 8] This is a diagram showing an example of the configuration of a planar antenna according to the eighth embodiment in a plan view. [Figure 9] This is a diagram showing an example of the configuration of a planar antenna according to the ninth embodiment in a plan view. [Figure 10] This is a diagram showing an example of the configuration of a planar antenna according to the tenth embodiment in a plan view. [Figure 11] This is a diagram showing an example of the simulation result of the planar antenna according to the first embodiment. [Figure 12] This is a diagram showing an example of the simulation result of the planar antenna according to the second embodiment. [Figure 13] This is a diagram showing an example of the simulation result of the planar antenna according to the third embodiment. [Figure 14] This is a diagram showing an example of the simulation result of the planar antenna according to the fourth embodiment. [Figure 15] This is a diagram showing an example of the simulation result of the planar antenna according to the fifth embodiment. [Figure 16] This is a diagram showing an example of the simulation result of the planar antenna according to the sixth embodiment. [Figure 17] This is a diagram showing an example of the simulation result of the planar antenna according to the seventh embodiment. [Figure 18]It is a diagram showing an example of the simulation result of the planar antenna of the eighth embodiment. [Figure 19] It is a diagram showing an example of the simulation result of the planar antenna of the ninth embodiment. [Figure 20] It is a diagram showing an example of the simulation result of the planar antenna of the tenth embodiment. [Figure 21] It is a diagram showing an example of the simulation result of the planar antenna when the slot length L2 of the second slot is changed. [Figure 22] It is a diagram showing the dimensions common to each planar antenna in each simulation. [Figure 23] It is a diagram showing the dimensions specific to the planar antenna of FIG. 1 in the simulation. [Figure 24] It is a diagram showing the dimensions specific to the planar antenna of FIG. 7 in the simulation. [Figure 25] It is a diagram showing the dimensions specific to the planar antenna of FIG. 8 in the simulation. [Figure 26] It is a diagram showing the dimensions specific to the planar antenna of FIG. 9 in the simulation. [Figure 27] It is a diagram showing the dimensions specific to the planar antenna of FIG. 10 in the simulation. [Figure 28] It is a cross-sectional view showing a configuration example of the planar antenna of the eleventh embodiment. <00,00116>When the shape of the planar antenna compatible with the frequency band of 600 MHz to 6 GHz without the matching circuit is taken as the original shape (100%), it is a diagram showing an example of each simulation result of the planar antenna of the original shape and the planar antenna of the shape reduced to 75% of the original shape. ) [Figure 30] It is a diagram showing the matching circuit during simulation. [Figure 31] It is a diagram showing an example of the simulation result of the planar antenna to which the matching circuit is added.

Embodiments for Carrying Out the Invention

[0010] The embodiments will be described below with reference to the drawings. Note that, for ease of understanding, the scale of the parts in the drawings may differ from the actual scale. A degree of deviation is permissible in directions such as parallel, right angles, orthogonal, horizontal, vertical, up and down, left and right, as well as in terms such as identical and equal, as long as it does not impair the function and effect of the embodiments.

[0011] Examples of vehicle window glass in this embodiment include a rear window installed at the rear of the vehicle, a windshield installed at the front of the vehicle, side windows installed at the sides of the vehicle, and roof glass installed on the ceiling of the vehicle. Vehicle window glass is not limited to these examples. Hereinafter, in this embodiment, vehicle window glass will also be simply referred to as window glass.

[0012] Figure 1 is a plan view showing an example of the configuration of a planar antenna according to the first embodiment. The planar antenna 101 shown in Figure 1 is a slot antenna having slots 10 formed in a flat conductor 20. Figure 1 is a plan view showing the planar antenna 101 attached to a part of the main surface of the window glass 100, from a planar view of the window glass 100 or the planar antenna 101. Note that the planar antenna of the first embodiment and the embodiments described later are not limited to being attached to the main surface of the window glass 100, but may also be attached to the main surface of a dielectric substrate such as a resin substrate. Examples of resin substrates include aero parts such as resin back doors and resin spoilers for vehicles.

[0013] The first, second, third, and fourth directions indicate the direction of the window glass 100 or the planar antenna 101 in a plan view. The third direction indicates the direction opposite to the first direction, and the fourth direction indicates the direction opposite to the second direction. In this embodiment, adjacent directions in the first, second, third, and fourth directions intersect at a right angle (may include approximate right angles). These descriptions can also be applied to other plan views.

[0014] The planar antenna 101 comprises a flat conductor 20 in which slots 10 are formed. Slots 10 are elongated notches formed in the conductor 20.

[0015] The conductor 20 is an example of a flat conductor in the form of a film or plate, and in this example, it is a conductive film (a film having conductivity) whose overall shape is substantially rectangular. In the first embodiment, the conductor 20 has an outer edge 91 on the first direction side, an outer edge 92 on the second direction side, an outer edge 93 on the third direction side, and an outer edge 94 on the fourth direction side.

[0016] The conductor 20 has a flat first conductor 21 that extends to one side of the slot 10 and a flat second conductor 22 that extends to the other side of the slot 10. In this embodiment, the first conductor 21 and the second conductor 22 are separated by the slot 10. The conductor 20, including the first conductor 21 and the second conductor 22, may be attached directly to the main surface of the window glass 100 or to be attached via the dielectric layer 120.

[0017] The planar antenna 101 may include a dielectric layer 120 on which a flat conductor 20 including a first conductor 21 and a second conductor 22 is formed. The conductor 20 may be a conductor formed by firing a paste containing a conductive metal (e.g., silver paste). The dielectric layer 120 may be black ceramic. Alternatively, for example, the planar antenna 101 may include a substrate (e.g., a flexible substrate) on which the flat conductor 20 including the first conductor 21 and the second conductor 22 is laminated on the dielectric layer 120. The dielectric layer 120 may be formed of a resin such as polyimide, and the conductor 20 may be formed of copper or the like. By having such a laminated structure in the planar antenna 101, dimensional deviations of slots 10, etc., can be suppressed even if the conductor 20 is divided into a first conductor 21 and a second conductor 22. In addition, it becomes easier to attach the planar antenna 101 to a mounting surface such as the main surface of a window glass 100.

[0018] The first conductor 21 has a first feed point 5 to which a signal line (not shown) is electrically connected, and the second conductor 22 has a second feed point 6 to which a ground wire (not shown) is electrically connected. For example, the inner conductor (signal line) at one end of the coaxial cable is electrically connected to the first feed point 5, and the outer conductor (ground wire) at the other end of the coaxial cable is electrically connected to the second feed point 6. The other end of the coaxial cable is connected to, for example, equipment having one or both of the transmitting and receiving functions. The area of ​​the first conductor 21 is larger than the area of ​​the second conductor 22.

[0019] Slot 10 includes slots 11, 12, 13, and J-shaped slot 30. Slots 13, 11, 12, and J-shaped slot 30 are connected in this order.

[0020] Slot 11 is an example of a first slot, extending in the first direction between the first power supply point 5 and the second power supply point 6.

[0021] Slot 12 is an example of a second slot, extending from the first-direction end 40 of slot 11 in a second direction different from the first direction.

[0022] Slot 13 is an example of a third slot. Slot 13 extends in a fourth direction from end 41 to an open end 42. End 41 is an example of the end of the first slot opposite to the first direction. Open end 42 is an example of an open end that opens in a fourth direction. Open end 42 opens at its outer edge 94 toward the fourth direction.

[0023] The J-shaped slot 30 is an example of a J-shaped slot. The J-shaped slot 30 extends in a J-shape from end 43 to open end 44. End 43 is an example of the end of the second slot in the second direction. Open end 44 is an example of an open end that opens in the first direction. The open end 44 opens at its outer edge 91 toward the first direction.

[0024] The slot width w44 at the open end 44 of the J-shaped slot 30 is wider than the slot width w43 at the second end 43 of the slot 12.

[0025] In this case, if the vehicle body is made of metal, and the radiating element of a wire antenna made of silver paste is placed close to the vehicle body on the window glass, the antenna's receiving gain tends to decrease due to interference with the metal.

[0026] However, since the planar antenna 101 according to this embodiment is a slot antenna, the electric field created by the current flowing through the conductor 20 is formed in a closed manner inside the conductor 20, and is therefore less susceptible to interference from metals or resins.

[0027] Therefore, the planar antenna 101 according to this embodiment can obtain stable characteristics even if metal objects such as a defogger or vehicle body are in close proximity to it, or even if resin parts of the vehicle body are in close proximity. Furthermore, even if a metal film such as a transparent conductive film is formed around it, it can similarly obtain characteristics that make it less susceptible to interference.

[0028] Communication frequencies vary from country to country, and even within a single country, different carriers use different frequency bands. Therefore, a broadband antenna capable of transmitting and receiving multiple communication waves is preferable.

[0029] The planar antenna 101 according to the first embodiment has a plurality of slots, such as slot 11, slot 12, slot 13, and J-shaped slot 30. The planar antenna 101 having such a plurality of slots is impedance-matched to be suitable for transmitting and receiving radio waves in the relatively high frequency band of the UHF (Ultra High Frequency) band and the 600MHz to 6GHz frequency band (sub6) used in fifth-generation communication (5G) standards.

[0030] The planar antenna 101 may be impedance-matched to efficiently transmit and receive Wi-Fi radio waves, which are part of a wireless LAN (Local Area Network). The planar antenna 101 may also be impedance-matched to transmit and receive radio waves in the frequency bands defined by the communication standards IEEE 802.11a, b, g, n, ac, ah, ax (e.g., 863MHz~868MHz (Europe), 902MHz~928MHz (USA), 2400MHz~2497MHz (worldwide), 5150MHz~5350MHz (worldwide), 5470MHz~5850MHz (worldwide)).

[0031] The planar antenna 101 may be impedance-matched to transmit and receive radio waves in the frequency range of 2400MHz to 2483.5MHz used by Bluetooth®. The planar antenna 101 may be impedance-matched to transmit and receive radio waves in the frequency bands used for vehicle-to-infrastructure (V2I) or vehicle-to-vehicle (V2V) communication in Intelligent Transport Systems (ITS) (e.g., 755.5MHz to 764.5MHz as defined in ARIB STD-T109 (Japan), 5850MHz to 5925MHz as defined in IEEE802.11p). The planar antenna 101 may be impedance-matched to transmit and receive radio waves in the frequency bands used by other wireless communication technologies such as WiMAX® (e.g., 2300MHz to 2400MHz, 2496MHz to 2690MHz, 3400MHz to 3600MHz). The planar antenna 101 may be impedance-matched to transmit and receive radio waves in the low band (3245MHz~4742MHz) of a UWB (ultra-wideband) wireless communication system.

[0032] Thus, according to the first embodiment, a wideband planar antenna capable of handling relatively high frequency bands up to about 6 GHz can be obtained, and a vehicle window glass equipped with the planar antenna can also be obtained.

[0033] In the example shown in Figure 1, the J-shaped slot 30 is a slot bent into a J-shape, formed so that a straight line bends in a J-shape. As a result, the J-shaped slot 30 includes multiple line segment slots that differ in at least one of their extending direction and length, making it easier to adjust the frequency for impedance matching.

[0034] In the example shown in Figure 1, the J-shaped slot 30 includes multiple line segment slots (slot 14, slot 15, and slot 16). Slot 14 is an example of a fourth slot, extending in a third direction from end 43. Slot 15 is an example of a fifth slot, extending in a second direction from the third end of slot 14. Slot 16 is an example of a sixth slot, extending in a first direction from the second end of slot 15 to the open end 44.

[0035] The J-shaped slot 30 may have a portion that extends in the first direction while maintaining substantially the same slot width. In the example shown in Figure 1, slot 16 extends in the first direction while maintaining substantially the same slot width. However, the J-shaped slot 30 may have a portion that extends in the first direction while gradually increasing or decreasing the slot width. For example, slot 16 may extend in the first direction toward the open end 44 while gradually increasing or decreasing the slot width.

[0036] In the example shown in Figure 1, the slot width of slot 16 is wider than that of slot 15, and the slot width of slot 15 is wider than that of slot 14. This makes impedance matching easier in the frequency band included in 600MHz to 6GHz. Note that the above frequency band also includes the 617MHz to 652MHz frequency band, which is defined as 5G band n71, for example.

[0037] In the example shown in Figure 1, the slot length of slot 15 is longer than the slot lengths of slot 14 and slot 16, so the shape of the planar antenna 101 can be made horizontally elongated in the second or fourth direction, and the external dimensions of the planar antenna 101 in the first or third direction can be shortened. As a result, when the planar antenna 101 is mounted on the window glass 100 such that the outer edge 91 or outer edge 93 follows a window frame (not shown), the view through the window glass 100 is less likely to be obstructed by the planar antenna 101. The window frame is a flange to which the window glass 100 is mounted.

[0038] In the example shown in Figure 1, slot 13 has a wider slot width than slot 11. This makes impedance matching easier in the frequency band included in 600MHz to 6GHz. However, the slot width of slot 13 may be the same as or narrower than the slot width of slot 11.

[0039] As shown in Figure 1, it is preferable that the slot length of slot 12 is shorter than the slot length of slot 11. This makes impedance matching easier in the high frequency band of 2.69 GHz to 6 GHz.

[0040] In the example shown in Figure 1, the outer edge 94 where the open end 42 of the slot 13 is located has a portion that passes through the open end 42 of the slot 13 and is parallel to a virtual line 94a that is perpendicular to the extension direction of the slot 13. However, the outer edge 94 may also have a portion that is inclined with respect to the virtual line 94a.

[0041] Figure 2 is a diagram showing a planar view of an example configuration of the planar antenna of the second embodiment. A description of the same configuration and effects as in the above-described embodiment will be omitted by referring to the above description. In the planar antenna 102 shown in Figure 2, the J-shaped slot 50 has a curved contour. The curved contour of the J-shaped slot 50 allows the planar antenna 102 to transmit and receive signals across a wider bandwidth.

[0042] The J-shaped slot 50 may have a portion where the slot width gradually increases. This allows the frequency range that the planar antenna 102 can transmit and receive to be broadened. As shown in Figure 2, the J-shaped slot 50 may have a portion that extends from the end 43 in the second direction of the slot 12 with a gradually increasing slot width, and then extends in the first direction while maintaining approximately the same slot width.

[0043] The J-shaped slot 50 may have a contour that is half the shape of an ellipse with a major axis substantially parallel to the second direction. This results in a smooth curve in the contour of the J-shaped slot 50, which allows the frequency range that the planar antenna 102 can transmit and receive to be broadened. The planar antenna 102 shown in Figure 2 is an example in which the slot width gradually increases until the extension direction of the J-shaped slot 50 is toward the first direction, and the slot width becomes substantially the same in the portion that extends parallel to the first direction.

[0044] Figure 3 is a diagram showing a planar view of an example configuration of a planar antenna according to the third embodiment. A description of the configuration and effects, which are the same as those of the embodiments described above, will be omitted by referring to the above description. In the planar antenna 103 shown in Figure 3, the outer edge 93 facing the outer edge 91 includes a curved portion 93a. The inclusion of the curved portion 93a in the outer edge 93 makes impedance matching easier in the frequency band of 750 MHz to 1 GHz. In addition, the amount of first conductor 21 used can be reduced, improving productivity. In the third embodiment, the curved portion 93a, which is the end of the outer edge 93, has a contour that is 1 / 4 of an ellipse with a major axis substantially parallel to the second direction, but it may have other curved contours such as a circle or a contour that is 1 / 4 or less of an ellipse.

[0045] Figure 4 is a diagram showing a planar view of an example configuration of the fourth embodiment of the planar antenna. A description of the configuration and effects, which are the same as those of the embodiments described above, will be omitted by referring to the above description. In the planar antenna 104 shown in Figure 4, the first conductor 21 and the second conductor 22 are formed in a grid shape having perforated portions (cut-out portions) in which a part of the conductor 20 is hollowed out. Cut-out portions may be formed in at least one of the first conductor 21 and the second conductor 22.

[0046] In a configuration where the conductor 20 is installed on the window glass 100 by printing, if the metallic area of ​​the conductor 20 is too large, the difference in heat absorption between the glass and the metal may reduce the moldability of the glass. By forming a cutout, the area of ​​the conductor 20 can be increased while ensuring the moldability of the glass. A larger area of ​​the conductor 20 improves the design flexibility of the slot antenna.

[0047] In this embodiment, in the region where the first power supply point 5 and the second power supply point 6 are not provided, a grid-like cutout section 23 is formed in the first conductor 21, and a grid-like cutout section 24 is formed in the second conductor 22. The shape of each cutout in the cutout section is not limited to a square, but may be a polygon other than a square (for example, a triangle and a hexagon), a circle, or other shape. Cutout sections may also be formed in other embodiments.

[0048] Figure 5 is a diagram showing a planar view of an example configuration of the fifth embodiment of the planar antenna. A description of the configuration and effects, which are the same as those of the embodiments described above, will be omitted by referring to the above description. In the planar antenna 105 shown in Figure 5, the outer edge 94 has a portion that is inclined with respect to the virtual line 94a. This makes impedance matching easier in the frequency band of 4GHz to 5GHz. In the fifth embodiment, the outer edge portion of the outer edge 94 on the outer edge 91 side with respect to the open end 42 protrudes in the fourth direction relative to the virtual line 94a, and the outer edge portion of the outer edge 94 on the outer edge 93 side with respect to the open end 42 is offset in the second direction relative to the virtual line 94a. Note that the dimensions of the protrusion and offset (5mm) shown in Figure 5 are just examples and can be set arbitrarily.

[0049] Figure 6 is a diagram showing a planar view of an example configuration of the sixth embodiment of the planar antenna. A description of the same configuration and effects as in the above-described embodiment will be omitted by referring to the above description. In the planar antenna 106 shown in Figure 6, the outer edge 94 has a portion that is inclined with respect to the virtual line 94a. This makes impedance matching easier in the frequency band of 4GHz to 5GHz. In the sixth embodiment, the outer edge portion of the outer edge 94 on the outer edge 91 side with respect to the open end 42 is offset to the second direction side with respect to the virtual line 94a, and the outer edge portion of the outer edge 94 on the outer edge 93 side with respect to the open end 42 protrudes to the fourth direction side with respect to the virtual line 94a. Note that the dimensions of the protrusion and offset (5mm) shown in Figure 6 are just examples and can be set arbitrarily.

[0050] Figure 7 is a diagram showing a planar view of an example configuration of the seventh embodiment of the planar antenna. A description of the configuration and effects, which are the same as those of the embodiments described above, will be omitted by referring to the above description. In the planar antenna 107 shown in Figure 7, the first conductor 21 has a first feed point 5 to which a signal line (not shown) is electrically connected, and the second conductor 22 has a second feed point 6 to which a grounding wire (not shown) is electrically connected. The area of ​​the second conductor 22 is larger than the area of ​​the first conductor 21.

[0051] Slot 10 includes slots 11, 12, 13, and 17. Slots 13, 11, 12, and 17 are connected in this order.

[0052] Slot 17 is an example of a seventh slot. Slot 17 extends from end 43 to open end 45. Open end 45 is an example of an open end that opens in a third direction. Open end 45 opens at its outer edge 93 toward the third direction.

[0053] The slot width w45 at the open end 45 of slot 17 is wider than the slot width w43 at the second end 43 of slot 12.

[0054] In the example shown in Figure 7, slot 17 includes multiple line segment slots (slot 14, slot 15, and slot 16). Slot 16 extends in a third direction from the second end of slot 15 to the open end 45.

[0055] As shown in Figure 7, it is preferable that the slot length of slot 12 is shorter than the slot length of slot 11. This makes impedance matching easier in the high frequency band of 2.69 GHz to 6 GHz.

[0056] Slot 17 may have a portion that extends in a third direction while maintaining substantially the same slot width. In the example shown in Figure 7, slot 16 extends in a third direction while maintaining substantially the same slot width. However, slot 17 may have a portion that extends in a third direction while gradually increasing or decreasing its slot width. For example, slot 17 may extend in a third direction toward the open end 45 while gradually increasing or decreasing its slot width.

[0057] Figure 8 is a diagram showing a planar view of an example configuration of the eighth embodiment of the planar antenna. A description of the configuration and effects, which are the same as those of the embodiments described above, will be omitted by referring to the above description. In the planar antenna 108 shown in Figure 8, the slot 17 extends in a third direction with the slot width gradually increasing toward the open end 45. For example, the slot 17 may have a portion that extends in a third direction with the slot width gradually increasing or decreasing toward the open end 45.

[0058] Figure 9 is a diagram showing a planar view of an example configuration of the ninth embodiment of the planar antenna. A description of the same configuration and effects as in the above-described embodiment will be omitted by referring to the above description. In the planar antenna 109 shown in Figure 9, the slot 17 has a curved contour. The curved contour of the slot 17 allows the planar antenna 109 to transmit and receive signals across a wider bandwidth.

[0059] Slot 17 may have a portion where the slot width gradually increases. This allows the frequency range that the planar antenna 109 can transmit and receive to be broadened. As shown in Figure 9, slot 17 may have a portion that extends from the end 43 in the second direction of slot 12 with a gradually increasing slot width, and then extends in a third direction while maintaining substantially the same slot width.

[0060] Slot 17 may have a contour of less than 1 / 4 of an ellipse having a major axis substantially parallel to the second direction (in the example shown in Figure 9, a contour of less than 1 / 4). This makes the contour of slot 17 a smooth curve, thus broadening the frequency range that the planar antenna 109 can transmit and receive. Slot 17 may have other curved contours, such as a contour of less than 1 / 4 of a circle or ellipse. The planar antenna 109 shown in Figure 9 is an example in which the slot width gradually increases until the extension direction of slot 17 is toward the third direction, and the slot width becomes substantially the same in the portion extending parallel to the third direction.

[0061] Figure 10 is a diagram showing a planar view of an example configuration of the tenth embodiment of the planar antenna. A description of the configuration and effects, which are the same as those of the embodiments described above, will be omitted by referring to the above description. In the planar antenna 110 shown in Figure 10, the outer edge 91 facing the outer edge 93 includes a curved portion 91a. The inclusion of the curved portion 91a in the outer edge 91 makes impedance matching easier in the frequency band of 750 MHz to 1 GHz. In addition, productivity is improved because the amount of second conductor 22 used can be reduced. In the tenth embodiment, the curved portion 91a, which is the end of the outer edge 91, has a contour that is 1 / 4 of an ellipse with a major axis substantially parallel to the second direction, but it may have other curved contours such as a circle or a contour that is 1 / 4 or less of an ellipse.

[0062] Figure 28 is a cross-sectional view showing an example of the configuration of the planar antenna of the 11th embodiment. A description of the configuration and effects, which are the same as those of the embodiments described above, will be omitted by referring to the above description. The planar antenna 200 shown in Figure 28 is enclosed in the window glass 100. The planar antenna 200 may be any of the planar antennas 101 to 110 of the embodiments described above.

[0063] A window glass 100 is attached to a window frame 66 formed in the vehicle body 62. The window glass 100 is attached to the window frame 66 by, for example, bonding the peripheral edge of the main surface 2b of the window glass 100 to the flange-shaped window frame 66 with an adhesive 65 such as urethane resin. The window frame 66 has a metal portion 63 that faces at least a part of the peripheral edge of the main surface 2b of the window glass 100 in a plan view. The inner edge 64 of the metal portion 63 forms an opening that is covered by the window glass 100 in a plan view of the window glass 100.

[0064] In the example shown in Figure 28, the window glass 100 is laminated glass in which a glass plate 1, which is placed on the outside of the vehicle, and a glass plate 2, which is placed on the inside of the vehicle, are bonded together with an interlayer 4 in between. The interlayer 4 is sandwiched between the glass plate 1 and the glass plate 2.

[0065] Glass plate 1 and glass plate 2 are transparent, plate-shaped dielectrics. Either or both of glass plate 1 and glass plate 2 may be semi-transparent. Glass plate 1 is an example of a first glass plate. Glass plate 2 is an example of a second glass plate facing the first glass plate.

[0066] The glass plate 1 has a main surface 1a and a main surface 1b opposite to the main surface 1a. The main surface 1a represents the surface on the outside of the vehicle, and the main surface 1b represents the surface on the inside of the vehicle.

[0067] The glass plate 2 has a main surface 2a facing the main surface 1b of the glass plate 1, and a main surface 2b opposite to the main surface 2a. The main surface 2a represents the outer surface of the vehicle, and the main surface 2b represents the inner surface of the vehicle. The main surface 2b is the surface opposite to the interlayer 4 of the glass plate 1.

[0068] The interlayer 4 is a dielectric material that is transparent or translucent and interposed between the glass plate 1 and the glass plate 2. The glass plate 1 and the glass plate 2 are joined by the interlayer 4. Examples of materials for the interlayer 4 include thermoplastic polyvinyl butyral (PVB), ethylene vinyl acetate copolymer (EVA), cycloolefin polymer (COP), and polyurethane.

[0069] The planar antenna 200 is formed on the main surface 2a of the glass plate 2. However, the planar antenna 200 may also be formed on the main surface 1b of the glass plate 1, or it may be placed between a plurality of interlayer films 4.

[0070] In the planar antenna 200, the first feed point 5 and the second feed point 6 are electrically connected to electrodes 7 facing each other across the glass plate 2 via capacitive coupling by the glass plate 2. The electrodes 7 include an electrode 7A facing the first feed point 5 and an electrode 7B facing the second feed point 6, and are planar conductors formed on the main surface 2b of the glass plate 2. The electrode 7A facing the first feed point 5 is electrically connected to a signal line of a transmission line (not shown), such as a coaxial cable, and the electrode 7B facing the second feed point 6 is electrically connected to a ground wire of a transmission line (not shown), such as a coaxial cable.

[0071] Next, the simulation results for the antennas of each embodiment will be described.

[0072] Figures 11 to 20 show examples of simulation results for planar antennas according to the first to tenth embodiments, respectively. VSWR represents the Voltage Standing Wave Ratio. A VSWR of 3.5 or less is preferable, and a value closer to 1 indicates better impedance matching. The frequencies used vary depending on the region or country, and in this example, the frequency band between 1 GHz and 1.7 GHz is considered unused in the 600 MHz to 6 GHz range. The VSWR in such unused frequency bands may exceed 3.5, for example. The indices in the above simulation results can also be applied to Figures 29 and 31.

[0073] In the case of the planar antenna 101 (Figure 1), as shown in Figure 11, the VSWR is 3.5 or less in the 1.7GHz to 6GHz band, resulting in impedance matching up to a relatively high frequency band of about 6GHz.

[0074] In the case of the planar antenna 102 (Figure 2), as shown in Figure 12, the VSWR in particular near 2.2 GHz to 3.2 GHz and near 4.7 GHz was improved compared to the case of the planar antenna 101 (Figure 1) shown in Figure 11.

[0075] In the case of the planar antenna 103 (Figure 3), as shown in Figure 13, the VSWR, particularly near 800 MHz and near 5 GHz, was improved compared to the case of the planar antenna 102 (Figure 2) shown in Figure 12.

[0076] In the case of the planar antenna 104 (Figure 4), as shown in Figure 14, the VSWR near 4.3 GHz was particularly improved compared to the case of the planar antenna 103 (Figure 3) shown in Figure 13.

[0077] In the case of the planar antenna 105 (Figure 5), as shown in Figure 15, the VSWR near 800 MHz was particularly improved compared to the case of the planar antenna 102 (Figure 2) shown in Figure 12.

[0078] In the case of the planar antenna 106 (Figure 6), as shown in Figure 16, the VSWR in the 4GHz to 4.5GHz range was particularly improved compared to the case of the planar antenna 102 (Figure 2) shown in Figure 12.

[0079] In the case of the planar antenna 107 (Figure 7), as shown in Figure 17, the VSWR near 4.3 GHz and near 5.9 GHz was particularly improved compared to the case of the planar antenna 101 (Figure 1) shown in Figure 11.

[0080] In the case of the planar antenna 108 (Figure 8), as shown in Figure 18, the VSWR was particularly improved in the vicinity of 3 GHz, 4.2 GHz to 4.5 GHz, and 5.8 GHz to 6.0 GHz compared to the case of the planar antenna 101 (Figure 1) shown in Figure 11.

[0081] In the case of the planar antenna 109 (Figure 9), as shown in Figure 19, the VSWR, particularly around 2.5 GHz and between 5.8 GHz and 6.0 GHz, was improved compared to the case of the planar antenna 101 (Figure 1) shown in Figure 11.

[0082] In the case of the planar antenna 110 (Figure 10), as shown in Figure 20, the VSWR in the 4.1GHz to 4.4GHz range was particularly improved compared to the case of the planar antenna 109 (Figure 9) shown in Figure 19.

[0083] Figure 21 shows an example of simulation results when the slot length L2 (in mm) of slot 12 is varied while the slot length L1 of slot 11 is fixed at 21.7 mm in the planar antenna 103 of the third embodiment (Figure 3). As shown in Figure 21, the shorter the slot length L2, the more likely the VSWR is to approach 1 across the entire frequency range shown in Figure 21, resulting in easier impedance matching.

[0084] In each simulation shown in Figures 11 to 21, the dimensions common to all planar antennas were set to the values ​​shown in Figure 22 (in mm). The dimensions unique to each planar antenna were set to the values ​​shown in Figures 23 to 27 (in mm).

[0085] Figure 29 shows examples of simulation results for a planar antenna with the original shape and a planar antenna with a shape reduced to 75% of the original shape, when the original shape (100%) is used as the shape of a planar antenna suitable for the frequency band of 600 MHz to 6 GHz. Figure 29 illustrates the case of planar antenna 103 (Figure 3).

[0086] In its original shape, the VSWR was 3.5 or less in the 600MHz~1.2GHz and 1.5GHz~6GHz bands, resulting in impedance matching up to relatively high frequency bands of around 6GHz. However, when the planar antenna 103 was scaled down with a similarity ratio of 1:0.75, the VSWR waveform shifted to higher frequencies overall, resulting in the appearance of bands with a VSWR exceeding 3.5 in the low-frequency band below 1.9GHz (excluding the unused frequency bands mentioned above). In other words, the antenna characteristics in the low-frequency band deteriorated.

[0087] Figure 30 shows an example of a matching circuit during simulation. Figure 31 shows an example of simulation results when the matching circuit 71 shown in Figure 30 is added to a planar antenna 103 with a shape reduced to 75%. As shown in Figure 31, by adding the matching circuit 71, the bandwidth in which the VSWR is 3.5 or less in the low frequency band below 1.9 GHz was expanded. Thus, by adding the matching circuit 71, it was possible to achieve both miniaturization of the planar antenna 103 and maintenance of antenna characteristics.

[0088] In the simulations shown in Figures 29 to 31, the conditions for each part are as follows: <Original shape (100%) planar antenna (without matching circuit)> Maximum outer dimensions of conductor 20 in the first direction: 40.0 mm Maximum external dimensions of conductor 20 in the second direction: 122.0 mm <A planar antenna with a shape reduced to 75% of the original (without matching circuitry)> Maximum outer dimensions of conductor 20 in the first direction: 30.0 mm Maximum external dimensions of conductor 20 in the second direction: 91.5 mm <A planar antenna with a shape reduced to 75% of the original (with matching circuitry)> Maximum outer dimensions of conductor 20 in the first direction: 30.0 mm Maximum external dimensions of conductor 20 in the second direction: 91.5 mm <Matching circuit 71> Capacitor C1: 8.2pF Inductor L1: 8.2nH That's what I decided.

[0089] The matching circuit 71 is an example of a matching circuit that performs impedance matching between the conductor 20 (antenna element pattern) and the transmission line (for example, a coaxial cable to which a signal line is electrically connected at the first feed point 5). By connecting the matching circuit 71 to the first feed point 5 and the second feed point 6, the deterioration of the antenna characteristics of the planar antenna of each embodiment of this disclosure can be suppressed even if the area of ​​the conductor 20 is reduced. In other words, miniaturization of the planar antenna of each embodiment of this disclosure and the assurance of antenna characteristics can be achieved simultaneously.

[0090] Although embodiments have been described above, the technology of this disclosure is not limited to the embodiments described above. Various modifications and improvements are possible, such as combinations or substitutions with some or all of the other embodiments.

[0091] For example, a planar antenna may be part of or all of the multiple antennas included in a diversity antenna or a MIMO (Multiple-Input and Multiple-Output) antenna. This improves communication quality. Furthermore, the entire contents of the specifications, claims, drawings, and abstracts of Japanese Patent Application No. 2021-170476, filed on October 18, 2021, and Japanese Patent Application No. 2022-043208, filed on March 17, 2022, are incorporated herein by reference as disclosure of the present invention. [Explanation of symbols]

[0092] 1 glass plate 2 glass plates 4 Interlayer 5. First power supply point 6. Second power supply point 7 electrodes 10-17 slots 20 Conductors 21 First Conductor 22 Second Conductor 23 Cutout section 24 Cutout section 30 J-shaped slots 40, 41, 43 Ends 42,44,45 Open end 50 J-shaped slots 62 car bodies 63 Metal parts 64 Common-law marriage 65 Adhesives 66 Window frame 71 Matching circuit 91, 92, 93, 94 Outer edge 91a,93a Curved part 94a Virtual Line 100 window glass 101-110 Planar antenna 120 Dielectric layer 200 Planar Antenna

Claims

1. It has slots formed in a flat conductor, The aforementioned slot is A first slot extending in the first direction between the first power supply point and the second power supply point, A second slot extends from the end of the first slot in the first direction in a second direction different from the first direction, The invention includes a third slot extending from the end of the first slot in a third direction opposite to the first direction, in a fourth direction opposite to the second direction, to an open end that opens in the fourth direction, and a J-shaped slot extending in a J-shape from the end of the second slot in a second direction to an open end that opens in the first direction, A planar antenna in which the slot width at the open end of the J-shaped slot is wider than the slot width at the end of the second slot in the second direction.

2. The planar antenna according to claim 1, wherein the J-shaped slot has a portion that extends in the first direction while maintaining substantially the same slot width.

3. The planar antenna according to claim 1, wherein the J-shaped slot has a curved contour.

4. The planar antenna according to claim 3, wherein the J-shaped slot has a portion in which the slot width gradually increases.

5. The planar antenna according to claim 2, wherein the J-shaped slot has a contour that is half the shape of an ellipse with a major axis substantially parallel to the second direction.

6. The planar antenna according to claim 1, wherein the J-shaped slot is a slot bent into a J-shape.

7. The planar antenna according to claim 6, wherein the J-shaped slot includes a fourth slot extending in the third direction from the other end of the second slot in the second direction, a fifth slot extending in the second direction, and a sixth slot extending in the first direction.

8. The slot width of the sixth slot is wider than the slot width of the fifth slot. The planar antenna according to claim 7, wherein the slot width of the fifth slot is wider than the slot width of the fourth slot.

9. The planar antenna according to claim 7, wherein the slot length of the fifth slot is longer than the slot length of the fourth slot and the slot length of the sixth slot.

10. The conductor has a first outer edge on which the open end of the J-shaped slot is located, and a second outer edge opposite to the first outer edge. The planar antenna according to claim 1, wherein the second outer edge includes a curved portion.

11. The planar antenna according to claim 10, wherein the end of the second outer edge has a contour of 1 / 4 or less of an ellipse having a major axis substantially parallel to the second direction.

12. The planar antenna according to claim 1, wherein the slot length of the second slot is shorter than the slot length of the first slot.

13. It has slots formed in a flat conductor, The aforementioned slot is A first slot extending in the first direction between the first power supply point and the second power supply point, A second slot extends from the end of the first slot in the first direction in a second direction different from the first direction, The invention comprises a third slot extending from the end of the first slot in a third direction opposite to the first direction, in a fourth direction opposite to the second direction, to an open end that opens in the fourth direction, and a seventh slot extending from the end of the second slot in a second direction to an open end that opens in the third direction, The slot width at the open end of the seventh slot is wider than the slot width at the end of the second slot in the second direction. A planar antenna in which the slot length of the second slot is shorter than the slot length of the first slot.

14. The planar antenna according to claim 13, wherein the seventh slot has a portion that extends in the third direction with substantially the same slot width.

15. The seventh slot has a curved contour, as described in claim 13, for the planar antenna.

16. The planar antenna according to claim 15, wherein the seventh slot has a portion in which the slot width gradually increases.

17. The planar antenna according to claim 14, wherein the seventh slot has a contour of 1 / 4 or less of an ellipse having a major axis substantially parallel to the second direction.

18. The conductor has a first outer edge on which the open end of the seventh slot is located, and a second outer edge opposite to the first outer edge. The planar antenna according to claim 13, wherein the second outer edge has a curved portion.

19. The planar antenna according to claim 18, wherein the end of the second outer edge has a contour of 1 / 4 or less of an ellipse having a major axis substantially parallel to the second direction.

20. The planar antenna according to claim 1, wherein the outer edge of the third slot having an open end has a portion that passes through the open end of the third slot and is parallel to a virtual line perpendicular to the extension direction of the third slot.

21. The planar antenna according to claim 1, wherein the outer edge of the third slot having an open end has a portion that is inclined with respect to a virtual line passing through the open end of the third slot and perpendicular to the extension direction of the third slot.

22. The planar antenna according to claim 1, wherein the third slot has a portion where the slot width is wider than that of the first slot.

23. The planar antenna according to claim 1, wherein matching circuits connected to the first feed point and the second feed point are attached.

24. A vehicle window glass comprising a planar antenna according to any one of claims 1 to 23.

25. It comprises a first glass plate and a second glass plate facing the first glass plate, The vehicle window glass according to claim 24, wherein the planar antenna is provided between the first glass plate and the second glass plate.

26. The vehicle window glass according to claim 24, wherein the planar antenna is part or all of a plurality of antennas included in a diversity antenna or MIMO antenna.

27. Vehicle window glass according to claim 24, for use as a windshield, side glass, rear glass, or roof glass.

Images