Antenna mounting system

Abstract

The present application relates to an antenna mounting system. An antenna mounting system provided with an antenna device (20) and a setting conductor plate (30) on which the antenna device (20) is set, the antenna device being provided with a ground plate (21), an opposed conductor plate (23), and a short-circuit pin (24) that shorts the opposed conductor plate (23) and the ground plate (21) at a position where an electric wave radiated vertically from the antenna device (20) toward the ground plate becomes an electric wave having a polarized wave component that vibrates in a direction parallel to a main polarized plane of an electric wave radiated vertically from the setting conductor plate (30) toward the ground plate, and a phase of the electric wave radiated vertically from the setting conductor plate (30) toward the ground plate deviates by 90 degrees or more and 270 degrees or less.

Description

[0001] Cross-reference to related applications

[0002] This application is based on Japanese Patent Application No. 2020-116682, filed on July 6, 2020, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This invention relates to an antenna mounting system, and in particular, to an antenna mounting system in which an antenna device utilizing zero-order resonance is mounted on a conductor plate. Background Technology

[0004] As an antenna device utilizing zero-order resonance, there exists an antenna device having the following components: a planar ground plane that is connected to the external conductor of a power supply cable and functions as ground; a planar conductor plate that is disposed opposite to the ground plane and has a power supply point provided at any position; and a short-circuit section that electrically connects the ground plane and the conductor plate (e.g., Patent Document 1).

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-111655

[0006] As shown in Patent Document 1, if the antenna device utilizing zero-order resonance is a single antenna device, when the short-circuit part is placed in the center of the conductor plate, it does not generate radiation in a direction perpendicular to the ground plane.

[0007] However, when the antenna device is installed on a conductor plate in a conductive system such as a vehicle body, current flows through the conductor plate due to the electromagnetic coupling between the antenna device and the conductor plate. Sometimes, this current can cause unwanted radiation in the direction perpendicular to the ground plane. Summary of the Invention

[0008] This disclosure is based on this situation, and its purpose is to provide an antenna mounting system that, in an antenna device utilizing zero-order resonance, can suppress unwanted radiation in the vertical direction to the ground plane when the antenna device is mounted on a conductor plate.

[0009] The aforementioned objectives are achieved through a combination of features described in the independent technical solutions. Furthermore, dependent technical solutions provide more advantageous specific examples. The reference numerals within parentheses in the claims indicate the correspondence between specific units described in the embodiments described below as an example, and are not intended to limit the scope of the disclosed technology.

[0010] One disclosure for achieving the above-mentioned objective is an antenna mounting system comprising an antenna device and a conductive plate for mounting the antenna device. The antenna device includes: a ground plane, which is a flat conductive component; a counter conductor plate, which is a flat conductive component disposed at a predetermined interval from the ground plane and electrically connected to a power supply line; and a short-circuit pin for electrically connecting the counter conductor plate to the ground plane.

[0011] The short-circuit pin shorts the opposing conductor plate and the ground plane at the following location: the location where the radio wave radiated from the antenna device in the vertical direction to the ground plane becomes a radio wave with a polarized wave component vibrating in a direction parallel to the main polarization plane of the radio wave radiated in the vertical direction from the conductor plate to the ground plane, and the phase deviation of the radio wave radiated in the vertical direction from the conductor plate to the ground plane is more than 90 degrees and less than 270 degrees.

[0012] The antenna mounting system uses electromagnetic coupling between the antenna device and the conductive plate to allow current to flow through the conductive plate. This current causes unwanted electromagnetic waves to radiate from the conductive plate in a direction perpendicular to the ground plane.

[0013] However, in this antenna mounting system, radio waves are also radiated vertically from the antenna device towards the ground plane. The main polarization of the radio waves radiated vertically from the antenna device towards the ground plane can be adjusted by observing the direction of the short-circuit pin connected from the center of the opposing conductor plate. Furthermore, the phase of the radio waves radiated vertically from the antenna device towards the ground plane can be adjusted by the distance from the center of the opposing conductor plate to the short-circuit pin.

[0014] In this antenna mounting system, the electromagnetic wave radiated by the antenna device in the direction perpendicular to the ground plane has a polarized wave component that vibrates in a direction parallel to the main polarization plane of the electromagnetic wave radiated from the conductor plate in the direction perpendicular to the ground plane. Furthermore, the phase of the electromagnetic wave radiated by the antenna device in the direction perpendicular to the ground plane is shifted by more than 90 degrees and less than 270 degrees from the phase of the electromagnetic wave radiated from the conductor plate in the direction perpendicular to the ground plane. With this phase difference, the signal strength of the synthesized wave is reduced compared to the strength of the electromagnetic wave radiated from the conductor plate in the direction perpendicular to the ground plane. Therefore, radiation in the direction perpendicular to the ground plane is suppressed. Attached Figure Description

[0015] Figure 1 This is a diagram showing the structure of the antenna mounting system 10.

[0016] Figure 2 This is a three-dimensional view of antenna device 20.

[0017] Figure 3 This is a cross-sectional view of the antenna mounting system 10.

[0018] Figure 4It is a conceptual diagram representing the current flowing through the conductor plate 30.

[0019] Figure 5 This is a diagram showing the current flowing through the opposing conductor plate 23.

[0020] Figure 6 This is a graph showing the relationship between the offset δ of the short-circuit pin 24 and the radiation gain.

[0021] Figure 7 This is a graph showing the relationship between the offset δ of the short-circuit pin 24 and the phase difference.

[0022] Figure 8 This is a graph showing the radiation gain of the antenna-mounted system 10 when δ = 0 mm.

[0023] Figure 9 This is a graph showing the radiation gain of the antenna-mounted system 10 when δ = 3 mm.

[0024] Figure 10 This diagram illustrates the antenna orientation direction Da.

[0025] Figure 11 This diagram illustrates the pin connection direction Dp. Detailed Implementation

[0026] The embodiments will now be described with reference to the accompanying drawings. Figure 1 This diagram illustrates the structure of the antenna mounting system 10 according to this embodiment. The antenna mounting system 10 has an antenna device 20 mounted on a conductor plate 30.

[0027] Figure 1 The conductor plate 30 is an experimental iron plate, rectangular in shape with dimensions of 650 × 80 mm. Hereinafter, the long side direction of the conductor plate 30 will be designated as the X direction, the width direction as the Y direction, and the direction perpendicular to the XY plane as the Z direction. In actual use of the antenna device 20, various conductor plates such as vehicle pillars and vehicle roof panels can be used as the conductor plate 30.

[0028] The center of the antenna device 20 in a top view is located 30 mm off-center in the Y direction from the center of the conductor plate 30 (hereinafter, the center of the conductor plate) 31. Furthermore, "top view" means viewing from a direction perpendicular to the XY plane. The antenna device 20 is positioned in the X direction at the same location as the center of the conductor plate 31.

[0029] exist Figure 2The image shows a perspective view of the antenna device 20. The antenna device 20 is mounted on a conductor plate 30 via a dielectric insulating plate 40. The insulating plate 40 is a thin, square plate. One pair of sides of the square of the insulating plate 40 is parallel to the X-axis, and the other pair of sides is parallel to the Y-axis. However, Figure 2 The shape of the isolation plate 40 shown is an example. The isolation plate 40 is provided for the purpose of isolating the antenna device 20 from the conductor plate 30, and its shape is not particularly limited. Alternatively, the antenna device 20 may be directly mounted on the conductor plate 30 without the isolation plate 40.

[0030] The antenna device 20 includes: a ground plane 21, a support plate 22, a counter conductor plate 23, and a short-circuit pin 24. The ground plane 21 is a plate-shaped conductor component made of a conductor such as copper. The ground plane 21 is disposed along the lower side of the support plate 22. The plate shape may also include a thin film such as metal foil. That is, the ground plane 21 may also be formed by patterning on the surface of a resin board such as a printed wiring board through electroplating or the like. This ground plane 21 is electrically connected to the outer conductor of a coaxial cable, providing a ground potential (in other words, a grounding potential). Furthermore, unless otherwise specified, connection hereafter means electrical connection.

[0031] The ground plane 21 is the same size as the partition plate 40 when viewed from above. Therefore, the ground plane 21 is formed as a square in the plane. However, the shape of the ground plane 21 is not limited to a square. Preferably, the ground plane 21 is symmetrical about each of two mutually orthogonal straight lines as an axis of symmetry (hereinafter, a two-way linearly symmetrical shape). A two-way linearly symmetrical shape is a figure that is symmetrical about a certain straight line as an axis of symmetry and is also linearly symmetrical about other straight lines orthogonal to that straight line. For example, ellipses, rectangles, circles, squares, regular hexagons, regular octagons, rhombuses, etc. are equivalent to two-way linearly symmetrical shapes. Preferably, the ground plane 21 is formed as a circle with a diameter greater than one wavelength.

[0032] The support plate 22 is shaped to overlap with the ground plane 21 and the isolation plate 40 when viewed from above. The support plate 22 serves to arrange the ground plane 21 and the opposing conductor plate 23 opposite each other at a predetermined interval. The support plate 22 is implemented using a dielectric material having a predetermined relative permittivity. The support plate 22 can utilize a printed circuit board with a substrate such as glass epoxy resin. For example, the support plate 22 can use glass epoxy resin with a relative permittivity of 4.3.

[0033] By adjusting the thickness of the support plate 22, the distance between the opposing conductor plate 23 and the ground plane 21 can be adjusted, as can the length of the short-circuit pin 24. When the distance between the opposing conductor plate 23 and the ground plane 21 and the length of the short-circuit pin 24 change, the frequency of the radio waves transmitted and received by the antenna device 20 changes. The specific value of the thickness of the support plate 22 can be appropriately determined through simulation and experimentation so that the frequency of the radio waves transmitted and received by the antenna device 20 is the desired frequency. When the frequency of the radio waves transmitted and received by the antenna device 20 is 2.45 GHz, the thickness of the support plate 22 is, for example, about 1 to 3 mm. This thickness is much shorter than 1 / 10 of the wavelength of the radio waves transmitted and received by the antenna device 20.

[0034] Furthermore, while this embodiment employs a structure where the space between the ground plane 21 and the opposing conductor plate 23 is filled with resin serving as a support plate 22, it is not limited to this. The space between the ground plane 21 and the opposing conductor plate 23 can also be hollow or a vacuum. Additionally, resin and space can be combined.

[0035] The opposing conductor plate 23 is a plate-shaped conductor component made of a conductor such as copper. As mentioned above, the plate shape may also include a thin film such as copper foil. The opposing conductor plate 23 is positioned opposite the ground plane 21 across the support plate 22. The opposing conductor plate 23, like the ground plane 21, may also be patterned on the surface of a resin board such as a printed wiring board. Furthermore, the parallelism here is not limited to perfect parallelism. It may also be tilted by a few degrees to about ten degrees. That is, it may include a generally parallel state (the so-called approximately parallel state).

[0036] By arranging the opposing conductor plate 23 and the ground plane 21 opposite each other, an electrostatic capacitance is formed that corresponds to the area of ​​the opposing conductor plate 23 and the spacing between the opposing conductor plate 23 and the ground plane 21. The opposing conductor plate 23 is configured to form an electrostatic capacitance that resonates in parallel with the inductance of the current path, such as the short-circuit pin 24, at a specified target frequency. The target frequency refers to the frequency of the object being transmitted or received.

[0037] The area of ​​the opposing conductor plate 23 is appropriately designed to provide the desired electrostatic capacitance (and thus operate at the target frequency). For example, the opposing conductor plate 23 is formed as a square with one side of 13 mm. When considering the wavelength shortening effect of the support plate 22, the length of this side is electrically equivalent to 0.2λ. Of course, the length of one side of the opposing conductor plate 23 can be appropriately changed.

[0038] Furthermore, as an example, the opposing conductor plate 23 is set to a square shape here, but as for other structures, the planar shape of the opposing conductor plate 23 can also be a circle, a regular octagon, a regular hexagon, etc. Additionally, the opposing conductor plate 23 can also be a rectangle, an elongated ellipse, etc. Preferably, the opposing conductor plate 23 has a bidirectional linearly symmetrical shape. More preferably, the opposing conductor plate 23 is a point-symmetrical shape such as a circle, a square, a rectangle, or a parallelogram.

[0039] Furthermore, slits can be provided in the opposing conductor plate 23, or the corners can be rounded. The edges of the opposing conductor plate 23 can also be partially or entirely formed into a curved shape. The bidirectional linear symmetry shape also includes the provision of minute (about a few millimeters) unevenness on its edges. Unevenness on the edges of the opposing conductor plate 23 to a degree that does not affect operation can be ignored. The technical concept of the planar shape of the opposing conductor plate 23 is the same for the grounding plate 21 described above.

[0040] A power supply line 25 is connected to the opposing conductor plate 23. In this embodiment, the power supply line 25 is connected to the opposing conductor plate 23 at a point that passes through the center of the opposing conductor plate 23 and divides the opposing conductor plate 23 in half. Figure 2 In the diagram, lines Lx and Ly are lines that pass through the center of the opposing conductor plate 23 and divide it into half. Line Lx is parallel to the X-axis, and line Ly is parallel to the Y-axis. The intersection of these two lines, Lx and Ly, is the center of the opposing conductor plate 23.

[0041] Furthermore, the connection point between the power supply line 25 and the opposing conductor plate 23 can be set at a position that matches the input and output impedance of the opposing conductor plate 23. For example, the connection point between the power supply line 25 and the opposing conductor plate 23 could be the edge or central area of ​​the opposing conductor plate 23.

[0042] In addition to the direct connection coupling power supply method used in this embodiment, various other methods, such as electromagnetic coupling, can be used as the method for supplying power to the opposing conductor plate 23. Electromagnetic coupling is a power supply method that utilizes the electromagnetic coupling between a microstrip line or similar device used for power supply and the opposing conductor plate 23.

[0043] The opposing conductor plate 23 is positioned opposite the ground plane 21 with one set of opposite sides parallel to the X-axis and the other set of opposite sides parallel to the Y-axis. In this embodiment, the opposing conductor plate 23 is configured such that the center of the ground plane 21 overlaps with the center of the opposing conductor plate 23 when viewed from above.

[0044] The short-circuit pin 24 is a conductive component that connects the ground plane 21 to the opposing conductor plate 23. Figure 3This is a cross-sectional view of the antenna mounting system 10 cut along a straight line Ly, perpendicular to the opposing conductor plate 23 and the ground plane 21. One end of the short-circuit pin 24 is connected to the opposing conductor plate 23, and the other end is connected to the ground plane 21. The short-circuit pin 24 can be implemented, for example, using a through-hole provided in the printed circuit board serving as the support plate 22. The short-circuit pin 24 can also be implemented using a conductive pin. The inductance of the short-circuit pin 24 can be adjusted by adjusting its length and diameter.

[0045] Furthermore, by adjusting the position of the short-circuit pin 24, the intensity and phase of the radio waves radiated by the antenna device 20 in the direction perpendicular to the ground plane can be adjusted. For example... Figure 2 As shown, when viewed from the center of the opposing conductor plate 23, the short-circuit pin 24 is connected to the opposing conductor plate 23 at a position offset from the center in the Y-axis direction, i.e., towards the width direction of the conductor plate 30. In this embodiment, the position of the short-circuit pin 24 is set to be 3 mm off-center from the center of the opposing conductor plate 23. Figure 7 The reasons will be explained later.

[0046] [Operation of Antenna Mounting System 10]

[0047] Next, the operation of the antenna mounting system 10 configured in this way will be explained. The opposing conductor plate 23 and the ground plane 21 are short-circuited via the short-circuit pin 24. The antenna device 20 performs LC parallel resonance at a resonant frequency determined by the inductance of the short-circuit pin 24 and the like, combined with the electrostatic capacitance between the opposing conductor plate 23 and the ground plane 21. As described above, the distance between the opposing conductor plate 23 and the ground plane 21, i.e., the thickness of the support plate 22, is much shorter than the wavelength of the radio waves transmitted and received by the antenna device 20. This resonance is a zero-order resonance.

[0048] Through this LC parallel resonance, an electric field perpendicular to both the ground plane 21 and the opposing conductor plate 23 is generated between the ground plane 21 and the opposing conductor plate 23. This perpendicular electric field propagates from the short-circuit pin 24 toward the edge of the opposing conductor plate 23, becoming a ground plane vertically polarized wave at the edge of the opposing conductor plate 23 and propagating in space. A ground plane vertically polarized wave refers to an electric wave whose vibration direction is perpendicular to the ground plane 21 or the opposing conductor plate 23. When the antenna device 20 is used in a position parallel to the horizontal plane, the ground plane vertically polarized wave refers to a polarized wave perpendicular to the ground (i.e., a typical vertically polarized wave).

[0049] Furthermore, when the aforementioned LC parallel harmonic is generated, an electric field is also generated between the conductor plate 30 and the opposing conductor plate 23. Current flows through the conductor plate 30 due to this electric field. Figure 4 The diagram conceptually illustrates the current flowing through a conductor plate 30. Figure 4 In the diagram, i1 to i7 represent the direction of the current flowing through the conductor plate 30.

[0050] Since the voltage generated by the conductor plate 30 is minimal directly below the antenna device 20, therefore... Figure 4 As shown, current flows through the conductor plate 30 directly below the antenna device 20.

[0051] Furthermore, since current flows through the conductor plate 30, electromagnetic waves are radiated from the conductor plate 30. Viewed from the conductor plate 30, the electromagnetic waves radiated from the conductor plate 30 also radiate in a vertical direction. In the antenna mounting system 10 of this embodiment, it is assumed that radiation in a vertical direction, as viewed from the conductor plate 30, is unnecessary.

[0052] Arrows i1 and i7 both represent currents along one side of the conductor plate 30, symmetrical about the location where the antenna device 20 is located. The currents represented by these arrows i1 and i7 are of the same magnitude but differ in direction by 180 degrees. This is because the antenna device 20 is positioned at the center of the conductor plate 30's long side and at its widest point.

[0053] The electromagnetic waves radiated from currents of equal magnitude but 180 degrees opposite in direction are of equal magnitude but opposite in direction. Therefore, the electromagnetic wave radiated vertically from the conductor plate 30 by the current indicated by arrow i1 cancels out the electromagnetic wave radiated vertically from the conductor plate 30 by the current indicated by arrow i7. For the same reason as arrows i1 and i7, the electromagnetic waves originating from the X components of arrows i2 and i6, and the X components of arrows i3 and i5, also cancel each other out.

[0054] However, electromagnetic waves radiated in the direction perpendicular to the conductor plate 30 due to the Y components of arrows i2, i3, i5, and i6, and the current indicated by arrow i4 parallel to the Y-axis, do not radiate from the conductor plate 30 to cancel out electromagnetic waves.

[0055] The electromagnetic wave radiated in the direction perpendicular to the conductor plate 30, originating from a current component parallel to the Y-axis, is a linearly polarized wave whose electric field vibration direction is parallel to the Y-axis. The principal polarization plane of this linearly polarized wave is a plane perpendicular to the ground plane 21 and the opposing conductor plate 23, and parallel to the Y-axis, i.e., parallel to the YZ plane. Hereinafter, a linearly polarized wave radiating in the Z-axis direction with its electric field vibration direction parallel to the Y-axis will be defined as a Y-axis parallel polarized wave.

[0056] Arrows i1 to i7 represent only a portion of the current flowing through the conductor plate 30. However, for the same reason as the electromagnetic waves radiated in the vertical direction of the conductor plate 30 by the X component of the current flowing through the conductor plate 30, the electromagnetic waves radiated in the vertical direction of the conductor plate 30 by the X component of the current flowing through the conductor plate 30 cancel each other out.

[0057] On the other hand, electromagnetic waves that radiate in the direction perpendicular to the conductor plate 30 through the Y component of the current flowing through the conductor plate 30 are not radiated from the conductor plate 30 to cancel out electromagnetic waves. Therefore, in this embodiment, electromagnetic waves that cancel out the Y-axis parallel polarized waves radiated from the conductor plate 30 are radiated from the antenna device 20.

[0058] exist Figure 5 The current flowing through the opposing conductor plate 23 is shown in the diagram. Short-circuit pin 24 is short-circuited to the opposing conductor plate 23 at a position offset from the center of the opposing conductor plate 23. Therefore, as... Figure 5 As shown in (A), the symmetry of the current distribution flowing through the opposing conductor plate 23 will be disrupted.

[0059] In detail, the short-circuit pin 24 is connected to the opposing conductor plate 23 at a position offset from the center of the opposing conductor plate 23 in the Y-axis direction. Therefore, the current flowing through the opposing conductor plate 23 is asymmetrical in the Y-axis direction with the opposing conductor plate 23 as the center.

[0060] The result is, as Figure 5 As shown in (B), the electromagnetic waves radiated by the current component flowing through the opposing conductor plate 23 in the Y-axis direction are not canceled out and remain. Therefore, linearly polarized waves with the electric field vibration direction parallel to the Y-axis radiate from the opposing conductor plate 23 in a direction perpendicular to the opposing conductor plate 23. That is, in this embodiment, Y-axis parallel polarized waves are also radiated from the antenna device 20.

[0061] Furthermore, since the current component in the X-axis direction maintains symmetry, the linearly polarized waves of the electric field oscillating in the X-axis direction cancel each other out. Therefore, the linearly polarized waves of the electric field radiated from the opposing conductor plate 23, whose oscillation direction is parallel to the X-axis, become negligible.

[0062] Unlike the antenna device 20, when viewed from the center of the opposing conductor plate 23, if the short-circuit pin 24 is deviated in the X-axis direction, a linearly polarized wave with the electric field vibration direction parallel to the X-axis radiates from the opposing conductor plate 23 in a direction perpendicular to the opposing conductor plate 23.

[0063] As can be seen from the above description, when the short-circuit pin 24 is deviated from the center of the opposing conductor plate 23, when viewed from the center of the opposing conductor plate 23, a linearly polarized wave with the direction of electric field vibration parallel to the direction connected to the short-circuit pin 24 radiates from the opposing conductor plate 23. That is, when the short-circuit pin 24 is deviated from the center of the opposing conductor plate 23, a linearly polarized wave with the direction of electric field vibration parallel to the opposing conductor plate 23 radiates from the opposing conductor plate 23.

[0064] Furthermore, the main polarization surface of the linearly polarized wave radiated from the antenna device 20 includes the direction from which the short-circuit pin 24 is connected from the center of the opposing conductor plate 23, and becomes a plane perpendicular to the XY plane. For example, as described above, if the short-circuit pin 24 is located in a direction parallel to the Y-axis when viewed from the center of the opposing conductor plate 23, then the main polarization surface is parallel to the YZ plane.

[0065] [The location of short-circuit pin 24 and the gain of the linearly polarized wave]

[0066] exist Figure 6 The diagram shows the relationship between the offset δ of the short-circuit pin 24 and the radiation gain of the linearly polarized wave radiated from the opposing conductor plate 23 by the antenna device 20. Furthermore, Figure 6 This refers to the gain of a single unit of the antenna device 20 that is not located on the conductor plate 30. The offset δ is the length by which the connection position of the short-circuit pin 24 is moved from the center of the opposing conductor plate 23 in the Y direction. Additionally, the positive side is the direction in which the center 31 of the conductor plate is located.

[0067] like Figure 6 As shown, the radiation gain increases when the absolute value of the offset δ increases. This is because the difference between the current flowing through the short-circuit pin 24 in the positive Y-axis direction and the current flowing through the short-circuit pin 24 in the negative Y-axis direction increases in the opposing conductor plate 23. Figure 6 In this context, -5dBi is the radiation gain of the linearly polarized wave radiated by the conductor plate 30 set in the antenna mounting system 10, and is a separately measured value.

[0068] When observing Figure 6 It is known that in order to use the Y-axis parallel polarized wave radiated by the antenna device 20 to cancel the Y-axis parallel polarized wave radiated by the conductor plate 30, the offset δ can be set to ±3mm or ±5.5mm.

[0069] However, the appropriate offset δ varies depending on the radiation gain of the linearly polarized wave radiated by the conductor plate 30 in the antenna mounting system 10. Furthermore, the radiation gain of the linearly polarized wave radiated by the conductor plate 30 varies depending on the magnitude of the current flowing through the conductor plate 30. The magnitude of the current flowing through the conductor plate 30 varies depending on the size of the conductor plate 30, the position of the antenna device 20 within the conductor plate 30, and so on. Therefore, the appropriate offset δ needs to be determined appropriately through measurement or the like.

[0070] [The location of short-circuit pin 24 and the phase of the linearly polarized wave]

[0071] exist Figure 7 The figure shows the offset δ of the short-circuit pin 24 and the phase difference relative to the phase when the offset δ = 0. Figure 7This also refers to the data for a single unit of antenna device 20. Observing the offset δ on the negative side, the larger the absolute value of the offset δ, the larger the phase difference. In other words, when the offset δ is on the negative side, the closer the offset δ is to 0, the smaller the phase difference.

[0072] The phase difference on the side with a positive offset δ is the same as the phase difference on the negative side plus 180 degrees. This is because if the offset directions are different, the current directions are opposite. For the phase difference on the side with a positive offset δ, the larger the absolute value of the offset δ, the larger the phase difference.

[0073] The reason why the phase difference between the larger the absolute value of the offset δ and the case where the offset δ = 0 mm is greater is that the larger the absolute value of the offset δ, the greater the inductance.

[0074] To cancel the Y-axis parallel polarized wave radiated by the conductor plate 30 with the Y-axis parallel polarized wave radiated by the antenna device 20, the phase difference between the phase of the Y-axis parallel polarized wave radiated by the antenna device 20 and the phase of the Y-axis parallel polarized wave radiated by the conductor plate 30 is preferably 180 degrees. If the above phase difference is 0 degrees when the offset δ = 0 mm, from Figure 7 It can be seen that the offset δ is preferably 3mm.

[0075] and Figure 6 The radiation gains shown are different, as mentioned above. Even if the absolute values ​​of the offset δ are the same, the phase difference will be different if the signs are different because the directions of the currents are opposite when the offset directions are different. For Figure 7 The offset δ in the middle is the positive side, and the direction from the center of the opposing conductor plate 23 to the short-circuit pin 24 is completely opposite to the direction from the center of the conductor plate 31 to the direction where the antenna device 20 is set.

[0076] Furthermore, the relationship between the offset δ and the phase difference also varies depending on the inductance of the opposing conductor plate 23. Therefore, even from the perspective of phase difference, an appropriate offset δ needs to be determined appropriately through measurement, etc.

[0077] Under the experimental conditions described, when considering phase difference in addition to radiation gain, an offset δ of 3 mm is preferred. Figure 8 , Figure 9 The effects of the implementation method are explained. Figure 8 , Figure 9 middle, G(θ) is the gain of the Y-axis parallel polarized wave, and G(θ) is the gain of the ground plane vertical polarized wave. Figure 8 It is the radiation gain of the antenna-mounted system 10 when the offset δ = 0 mm. Figure 9 It is the radiation gain of the antenna-mounted system 10 when the offset δ = 3 mm.

[0078] exist Figure 8 and Figure 9 In the comparison of the parts enclosed by the dashed line, it can be seen that by setting the offset δ = 3mm, the gain in the Z-axis direction can be reduced.

[0079] [Summary of Implementation Methods]

[0080] The antenna mounting system 10 is electromagnetically coupled to the conductive plate 30 via the antenna device 20, causing current to flow through the conductive plate 30 as well. This current causes unwanted electromagnetic waves to radiate from the conductive plate 30 in a direction perpendicular to the ground plane. In this embodiment, the unwanted electromagnetic waves radiating from the conductive plate 30 in a direction perpendicular to the ground plane are Y-axis parallel polarized waves.

[0081] The antenna device 20 has a structure that radiates a portion of the unwanted radio waves. Specifically, for the antenna device 20, the short-circuit pin 24 short-circuits the opposing conductor plate 23 to the ground plane 21 in a direction offset from the center of the opposing conductor plate 23. As a result, radio waves are also radiated from the antenna device 20 in a direction perpendicular to the ground plane.

[0082] The main polarization plane of the radio wave radiated from the antenna device 20 in the direction perpendicular to the ground plane can be adjusted by determining the orientation of the position where the short-circuit pin 24 is connected, as viewed from the center of the opposing conductor plate 23. In this embodiment, the short-circuit pin 24 is positioned in a direction parallel to the Y-axis when viewed from the center of the opposing conductor plate 23. Thus, similar to the radio wave radiated from the conductor plate 30, the antenna device 20 also radiates a Y-axis parallel polarized wave.

[0083] Furthermore, the phase of the radio wave radiated from the antenna device 20 in the vertical direction toward the ground plane can be adjusted by the distance from the center of the opposing conductor plate 23 to the short-circuit pin 24. Therefore, in this embodiment, this distance is adjusted so that the phase of the Y-axis parallel polarized wave radiated by the antenna device 20 is a phase that deviates by 180 degrees from the phase of the Y-axis parallel polarized wave radiated from the disposed conductor plate 30.

[0084] With a 180-degree phase difference, the signal strength of the combined wave of the Y-axis parallel polarized wave radiated by the conductor plate 30 and the antenna device 20 is reduced compared to the strength of the Y-axis parallel polarized wave radiated by the conductor plate 30. Therefore, unwanted radiation, i.e., radiation perpendicular to the ground plane, is suppressed.

[0085] The implementation methods have been described above, but the disclosed technology is not limited to the above-described implementation methods. The following variations are also included in the scope of the disclosure, and various changes and implementations can be made without departing from the spirit of the text, except as described below.

[0086] <Variation Example 1>

[0087] [Other ways to position the antenna and the short-circuit pin]

[0088] In this embodiment, the antenna device 20 is moved only from the center 31 of the conductor plate in the Y-axis direction. However, the placement position of the antenna device 20 is arbitrary. Figure 10 The diagram shows an example of an antenna device 20 positioned after being moved from the center 31 of the conductor plate in both the Y-axis and X-axis directions. Viewed from the center 31 of the conductor plate, the direction on the conductor plate 30 toward the center of the antenna device 20 is defined as the antenna mounting direction Da.

[0089] exist Figure 11 The pin connection direction Dp is shown in the diagram. The pin connection direction Dp is from the center of the opposing conductor plate 23 towards the location where the short-circuit pin 24 is connected in the opposing conductor plate 23. Additionally, in... Figure 11 In the example shown, the angle difference ΔD between the antenna setting direction Da and the pin connection direction Dp is 180 degrees. Figure 11 As shown, the angle difference ΔD between the antenna setting direction Da and the pin connection direction Dp is the smaller of the differences between the angles of the arrow representing the antenna setting direction Da and the arrow representing the pin connection direction Dp when the starting points of the antenna setting direction Da and the pin connection direction Dp are aligned.

[0090] The antenna orientation direction Da signifies the direction of the main polarization surface of the electromagnetic wave radiated by the conductor plate 30. Furthermore, the pin connection direction Dp signifies the direction of the main polarization surface of the electromagnetic wave radiated by the antenna device 20 from the opposing conductor plate 23. Therefore, as long as the pin connection direction Dp is not orthogonal to the antenna orientation direction Da, the electromagnetic wave radiated from the antenna device 20 in the direction perpendicular to the ground plane has a polarization wave component that vibrates in a direction parallel to the main polarization surface of the electromagnetic wave radiated from the conductor plate 30 in the direction perpendicular to the ground plane.

[0091] In order to cancel the electromagnetic waves radiated from the opposing conductor plate 20 by the antenna device 20, it is preferable that the principal polarization planes of their electromagnetic waves are parallel. Therefore, it is preferable that the pin connection direction Dp is as close as possible to parallel with the antenna setting direction Da, and most preferably, the pin connection direction Dp is parallel to the antenna setting direction Da. From this point of view, it is preferable that the angle difference ΔD is 0 degrees or more and 30 degrees or less, or 150 degrees or more and 180 degrees or less. Figure 11 The figure shows the range of the preferred angle difference ΔD.

[0092] Furthermore, from the perspective of phase difference, such as Figure 7As shown, the direction in which the short-circuit pin 24 is offset is preferably the opposite direction to the direction in which the antenna device 20 is located, as viewed from the center 31 of the conductor plate. That is, it is particularly preferred that the angle difference ΔD is 150 degrees or more and 180 degrees or less. Furthermore, a narrower angle range is preferred, for example, an angle difference ΔD of 165 degrees or more and 180 degrees or less is preferred.

[0093] <Variation Example 2>

[0094] [Other ways to determine phase difference]

[0095] In this embodiment, the phase difference between the electromagnetic wave radiated by the opposing conductor plate 23 of the antenna device 20 and the electromagnetic wave radiated by the setting conductor plate 30 is 180 degrees. To reduce the signal strength of the synthesized wave, a phase difference of 180 degrees is most preferably preferred. However, even if the phase difference is not 180 degrees, the signal strength of the synthesized wave can still be made weaker than the electromagnetic wave radiated by the setting conductor plate 30.

[0096] As the phase difference becomes less than 180 degrees, the degree to which the electromagnetic waves radiated by the opposing conductor plate 23 of the antenna device 20 cancel out the electromagnetic waves radiated by the setting conductor plate 30 decreases, and within a certain phase range, the electromagnetic waves reinforce each other. Moreover, when the phase difference is 0 degrees, the composite wave is the strongest.

[0097] Based on this, if the phase difference is ±90 degrees with a reference of 180 degrees, the signal strength of the synthesized wave can be made weaker than the radio wave radiated by the conductor plate 30. That is, when the phase of the radio wave radiated by the opposing conductor plate 23 of the antenna device 20 deviates from the phase of the radio wave radiated by the conductor plate 30 by more than 90 degrees and less than 270 degrees, the signal strength of the synthesized wave can be made weaker than the radio wave radiated by the conductor plate 30. Of course, the closer the phase difference is to 180 degrees, the more preferred it is; therefore, for example, a phase difference of more than 135 degrees and less than 225 degrees is preferred.

Claims

1. An antenna mounting system comprising an antenna device and a conductive plate for mounting the antenna device, the antenna device comprising: a ground plane, which is a flat conductive member; a counter conductive plate, which is a flat conductive member disposed at a predetermined interval from the ground plane and electrically connected to a power supply line; and a short-circuit pin for electrically connecting the counter conductive plate to the ground plane. The aforementioned short-circuit pin shorts the aforementioned opposing conductor plate and the aforementioned ground plane at the following location: the location is where the electromagnetic wave radiated from the aforementioned antenna device in the vertical direction to the ground plane becomes a polarized wave component that vibrates in a direction parallel to the main polarization plane of the electromagnetic wave radiated from the aforementioned conductor plate in the vertical direction to the aforementioned ground plane, and the phase of the electromagnetic wave radiated from the aforementioned conductor plate in the vertical direction to the aforementioned ground plane deviates from the phase of the electromagnetic wave by more than 90 degrees and less than 270 degrees.

2. The antenna mounting system according to claim 1, wherein, The angle difference between the antenna setting direction and the pin connection direction is 0 degrees or more and 30 degrees or less, or 150 degrees or more and 180 degrees or less. The antenna setting direction is from the center of the conductor plate to the position where the antenna device is set. The pin connection direction is from the center of the opposing conductor plate to the position where the short-circuit pin is connected in the opposing conductor plate.

3. The antenna mounting system according to claim 2, wherein, The angle difference between the antenna setting direction and the pin connection direction is more than 150 degrees and less than 180 degrees.

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