JP6299505B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device that transmits and receives radio waves having two different frequencies.

  In Patent Document 1, radio waves having two different frequencies are transmitted and received by arranging a patch antenna element corresponding to a first frequency radio wave and a coil antenna element corresponding to a second frequency on a dielectric substrate. An antenna device is disclosed.

  More specifically, the patch antenna element is disposed inside the coil antenna element on one surface (the front surface) of the dielectric substrate, and the ground plane for the patch antenna element is disposed on the back surface of the dielectric substrate. Here, the outer periphery of the patch antenna element and the coil antenna element are arranged apart from each other in the opposite directions by at least twice the thickness of the dielectric substrate with respect to the outer periphery of the ground plane.

  By disposing the patch antenna element and the coil antenna element in such a manner, the isolation between the antenna elements is reduced, and the radiation characteristics of each antenna element are ensured.

  Here, the isolation refers to the magnitude of a signal received by the other antenna element (non-target element) when radio waves are emitted from one antenna element (target element). . When a current flows through a non-target element due to a radio wave from the target element, the radiation characteristics of a radio wave having a frequency corresponding to the target element are deteriorated.

Japanese Patent No. 4142523

  In general, the magnitude of isolation is determined by the positional relationship (distance, etc.) between two antenna elements with respect to the wavelength of a radio wave to be transmitted and received. When the distance between the antenna elements is sufficiently far away from the wavelength of the target radio wave, current is hardly induced in the non-target element. In other words, when the distance between the antenna elements is sufficiently close to the wavelength of the radio wave to be transmitted / received (interference distance), a current flows through the non-target element.

  In Patent Document 1, two antenna elements, that is, a patch antenna element and a coil antenna element are arranged apart from each other, thereby reducing isolation between the antenna elements.

  However, increasing the distance between the antenna elements leads to an increase in the size of the antenna device. Further, further miniaturization of the antenna device is desired from the viewpoint of mountability on a moving body such as a vehicle. That is, there is a demand for realizing a reduction in size of the antenna device while keeping the isolation between the antenna elements within a desired allowable range.

  Since the frequency of radio waves is lower as the frequency is lower, the interference distance is longer as the frequency of radio waves to be transmitted / received is lower, and the distance between antenna elements necessary to keep the isolation within a desired tolerance range is become longer.

  Therefore, in an antenna device that targets radio waves of the first and second frequencies, isolation in a radio wave having a relatively low frequency is more problematic than isolation in radio waves having a relatively high frequency.

  The present invention has been made based on this situation, and an object of the present invention is to reduce the size of the antenna device in an antenna device including two antenna elements corresponding to radio waves having two different frequencies. On the other hand, an object of the present invention is to provide an antenna device capable of suppressing isolation of radio waves having a relatively lower frequency of two frequencies.

  In order to achieve the object, the present invention is an element for carrying out at least one of transmission and reception of a conductor ground plane (2) and a radio wave of the first frequency, and has a predetermined distance from the conductor ground plane. From the first frequency, the first frequency element (3, 3B) having a flat plate shape, the first frequency feeding element (4, 4B) electrically connecting the first frequency element and the power supply line, A second frequency element (5, 5B, 5C, 6, 6B) that is a linear element for performing at least one of transmission and reception of a radio wave having a low second frequency, for the second frequency The element is provided outside the conductor ground plane, and is opposed to a second element side facing portion (51, 51B, 51C, 51) facing a part of the outer periphery of the conductor ground plane and a part of the outer periphery of the first frequency element. 61, 61B), and the conductor ground plane faces the second element side facing portion. An outer peripheral portion and a ground plane side facing portion (21, 21B, 22, 22B) which is a portion closest to the second element side facing portion in the conductor ground plane, and the first frequency element is a second A first element side facing portion (32, 32B, 33, 33B) which is an outer peripheral portion facing the element side facing portion and is a portion closest to the second element side facing portion in the first frequency element. Each of the conductor ground plane and the first frequency element with respect to the second element side facing portion has substantially the same amplitude in the ground plane side facing portion and the first element side facing portion due to a current flowing through the second frequency element. In the first frequency element, the first power supply portion is provided closer to the first element side facing portion side than the center portion thereof.

  In the above configuration, when transmitting radio waves of the second frequency, an electric field starting from the first element side facing portion is generated in the first frequency element due to the current flowing through the second frequency element. The electric field is attenuated and the phase is delayed as the distance from the first element side facing portion increases. In addition, an electric field starting from the ground plane side facing portion is also generated on the conductor ground plane due to the current flowing through the second frequency element.

  Generally, when an electric field is generated in the first frequency element when transmitting a radio wave of the second frequency, a current flows through the first power feeding unit.

  However, in the above configuration, the electric field generated in the first element side facing portion and the electric field generated in the ground plane side facing portion due to the current flowing in the second frequency element have substantially the same amplitude and phase. Therefore, if the first power feeding part is provided in the vicinity of the first element side facing part, the difference in electric field between the conductor ground plane and the first frequency element is small, and current does not easily flow through the first power feeding part.

  In addition, the state where the amplitude and phase of the electric field of the first element side facing portion and the ground plane side facing portion here are substantially the same is when the first power feeding portion is provided in the vicinity of the first element side facing portion. A state in which the current flowing through the first power feeding unit is within a predetermined allowable range due to the difference between the electric fields.

  Further, the deviation in amplitude and phase between the electric field generated in the conductor ground plane and the electric field generated in the first frequency element increases as the distance from the second frequency element increases. For this reason, the electric current which flows through a 1st electric power feeding part increases as the installation position of a 1st electric power feeding part is separated from the 1st element side opposing part. However, even if it is some distance from the first element side facing portion, it is assumed that the current flowing through the first power feeding portion due to the deviation of the electric field falls within the allowable range. If at least the first power feeding portion is provided on the first element side facing portion side of the first frequency element, the electric field of the conductor ground plane and the amplitude and phase of the electric field of the first frequency element It can be expected that the current caused by the deviation is suppressed.

  Therefore, according to the above configuration, in an antenna device including two antenna elements corresponding to radio waves of two different frequencies, the lower one of the two frequencies (that is, the second frequency) Isolation between antenna elements for radio waves can be suppressed.

  In addition, various configurations can be assumed as the configuration in which the electric field that can be regarded as having substantially the same amplitude and phase in the first element side facing portion and the ground plane side facing portion is generated by the current flowing through the second frequency element. In such a configuration, the first frequency element, the conductor ground plane, and the second frequency element are sufficiently sufficient for the wavelength of the radio wave of the second frequency (for example, less than 1/50 of the wavelength). Configurations that are close together are included.

  That is, according to the above configuration, it is not necessary to separate the first frequency element, the conductor ground plane, and the second frequency element by an interference distance determined according to the wavelength of the second frequency radio wave. Thereby, the antenna device can be downsized.

  Therefore, according to the above configuration, in an antenna device including two antenna elements corresponding to radio waves of two different frequencies, the antenna device is reduced in size and is isolated from radio waves of a relatively lower frequency. Can be suppressed.

  In addition, the code | symbol in the parenthesis described in the claim shows the correspondence with the specific means as described in embodiment mentioned later as one aspect, Comprising: The technical scope of this invention is limited is not.

It is a perspective view showing a schematic structure of antenna device 100 concerning this embodiment. It is a top view which shows the schematic structure of the antenna apparatus 100 which concerns on this embodiment. It is sectional drawing in the III-III line in FIG. It is the figure which extracted the structure for transmitting / receiving the electromagnetic wave of 1st frequency in the antenna device. It is the figure which extracted the structure for transmitting / receiving the electromagnetic wave of 2nd frequency in the antenna apparatus. It is a figure which shows the positional relationship of the to-be-powered element 5 and the parasitic element 6 with respect to the ground plane 2. FIG. It is a conceptual diagram for demonstrating the action | operation of the antenna apparatus 100 at the time of transmitting / receiving the electromagnetic wave of a 2nd frequency. It is a conceptual diagram for demonstrating the action | operation of the antenna apparatus 100 at the time of transmitting / receiving the electromagnetic wave of a 2nd frequency. It is a conceptual diagram for demonstrating the action | operation of the antenna apparatus 100 at the time of transmitting the electromagnetic wave of a 2nd frequency. It is a figure for demonstrating the interaction of the structure for 1st frequency 101 and the structure for 2nd frequency 102 at the time of transmitting / receiving the electromagnetic wave of a 2nd frequency. It is a top view which shows an example of the schematic structure of the comparison structure 100X. It is a figure showing the result of having compared the isolation with respect to the electromagnetic wave of a 2nd frequency in the comparison structure 100X and the antenna apparatus 100 of embodiment. It is a figure showing the result of having compared the axial ratio of the circularly polarized wave of the 2nd frequency in the comparison structure 100X and the antenna apparatus 100 of embodiment. 10 is a plan view illustrating an example of a schematic configuration of an antenna device 100A according to Modification 2. FIG. FIG. 11 is a plan view illustrating an example of a schematic configuration of an antenna device 100B according to Modification 3. FIG. 10 is a plan view illustrating an example of a schematic configuration of an antenna device 100C according to Modification 4.

<Embodiment>
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view illustrating an example of a schematic configuration of an antenna device 100 according to the present embodiment. FIG. 2 is a plan view of the antenna device 100.

  The antenna device 100 is used, for example, in a vehicle, and transmits / receives circularly polarized waves having two different frequencies, or performs either one of transmission and reception. More specifically, the antenna device 100 transmits and receives radio waves in a frequency band used for communication with a roadside device used in an ETC (Electronic Toll Collection: registered trademark) system, and transmits from a satellite used in a satellite positioning system. Receive radio waves. The antenna device 100 may be attached to, for example, an upper part of a windshield of a vehicle.

  A radio wave of 5.8 GHz band is used for wireless communication with the roadside device of the ETC system. The satellite used in the satellite positioning system corresponds to, for example, a GPS satellite used in GPS (Global Positioning System). The 1.5 GHz band is used for GPS radio waves.

  That is, the antenna device 100 transmits and receives 5.8 GHz band circularly polarized waves as the first frequency, and transmits and receives 1.5 GHz band radio waves as the second frequency. The wavelength of the radio wave at the first frequency (referred to as the first wavelength) is approximately 52 mm in vacuum, and the wavelength of the radio wave at the second frequency (referred to as the second wavelength) is approximately 200 mm. Of course, these lengths are shorter for the antenna device 100 due to the wavelength shortening effect of the dielectric.

  The antenna device 100 is connected to a radio (not shown) via a coaxial cable, for example, and signals received by the antenna device 100 are sequentially output to the radio. The wireless device uses a signal received by the antenna device 100 and supplies high-frequency power corresponding to the transmission signal to the antenna device 100. In the present embodiment, description will be made on the assumption that a coaxial cable is employed as a feed line to the antenna device 100, but other known feed lines such as a feeder line may be used.

  The antenna device 100 and the radio device may be connected by two coaxial cables corresponding to the first frequency and the second frequency, respectively, or may be connected by one coaxial cable. In the present embodiment, as an example, the antenna device 100 is connected to a radio using a single coaxial cable using a switch circuit or a filter circuit for switching the frequency of a signal to be transmitted / received.

  Of course, as another aspect, the antenna device 100 and the wireless device are connected by two cables: a coaxial cable for transmitting and receiving a first frequency signal and a coaxial cable for transmitting and receiving a second frequency signal. May be.

(About overall configuration)
Hereinafter, a specific configuration and operation of the antenna device 100 will be described. As shown in FIGS. 1 and 2, the antenna device 100 includes a substrate 1, a ground plane 2, a patch antenna element 3, a first feeding unit 4, a fed element 5, a parasitic element 6, and a second feeding unit 7. Yes. 3 is a cross-sectional view of the antenna device 100 taken along the line III-III shown in FIG.

  The antenna device 100 has a configuration for transmitting / receiving a first frequency radio wave shown in FIG. 4 (first frequency configuration 101) and a configuration for transmitting / receiving a second frequency radio wave shown in FIG. 5 (second frequency). And the configuration 102).

  The 1st electric power feeding part 4 is an electrical connection part of the patch antenna element 3 and the ground plane 2, and a coaxial cable. More specifically, the first feeder 4 electrically connects the outer conductor (minus side conductor) of the coaxial cable and the ground plane 2, and also connects the inner conductor (plus side conductor) of the coaxial cable and the patch antenna. This is realized by electrically connecting the element 3. In addition, the 1st electric power feeding part 4 also plays the role of the support member which supports the patch antenna element 3 so that it may become the attitude | position arrange | positioned facing the ground plane 2 with the predetermined space | interval D21 so that it may mention later.

  The 2nd electric power feeding part 7 is an electrical connection part of the to-be-powered element 5, the ground plane 2, and a coaxial cable. The second power feeding unit 7 is realized by electrically connecting the outer conductor of the coaxial cable and the ground plane 2 and electrically connecting the inner conductor of the coaxial cable and the fed element 5.

  In addition, in this embodiment, although it is set as the structure which provides the electrical connection part of the ground plane 2 and the outer conductor of a coaxial cable in both the 1st electric power feeding part 4 and the 2nd electric power feeding part 7, as any other aspect, Only one side may be configured to be electrically connected to the outer conductor of the coaxial cable.

  Various circuits such as an impedance matching circuit, a switch circuit, and a filter circuit are interposed between the patch antenna element 3 and the inner conductor of the coaxial cable and between the fed element 5 and the inner conductor of the coaxial cable. It may be. The same applies to the connecting portion between the main plate 2 and the coaxial cable.

  The substrate 1 is a flat plate member made of an electrically insulating material such as resin. In the present embodiment, as an example, the base plate 2, the patch antenna element 3, the first feeding unit 4, the fed element 5, the parasitic element 6, and the second feeding unit 7 are provided on one side (the front side) of the substrate 1. It is set as the structure to provide. The ground plane 2, the fed element 5, and the parasitic element 6 are arranged directly on the same plane, that is, on the surface of the substrate 1.

  The shape of the board | substrate 1 should just be sufficient magnitude | size and shape in order to arrange | position the base plate 2, the to-be-powered element 5, and the parasitic element 6. FIG. In the present embodiment, a square is used as an example, but a rectangle or a circle (including an ellipse) may be used. As the material of the substrate 1, a material having a desired relative dielectric constant may be appropriately selected and used.

  The ground plane 2 is a flat plate member (including a foil and a film) made of a conductor such as copper. This ground plane 2 corresponds to the conductor ground plane described in the claims. The ground plane 2 is electrically connected to the outer conductor of the coaxial cable. As an example, the shape of the ground plane 2 is a square in which the electrical length of one side is less than a quarter of the second wavelength and has a predetermined length greater than the half wavelength of the first wavelength.

  The electrical length is a value determined in consideration of the influence of a fringing electric field and a wavelength shortening effect by a dielectric (for example, the substrate 1), and is also referred to as an effective length. In the present embodiment, the shape of the base plate 2 is a square, but may be a rectangle or a circle.

  The ground plane 2 is electrically connected to the parasitic element 6 at one point on a certain side 21 among four sides corresponding to the outer peripheral portion. The ground plane 2 is connected to the power-supplied element 5 through the second power supply unit 7 at one point on the side 22 orthogonal to the side 21 to which the parasitic element 6 is connected. In the ground plane 2, a point connected to the parasitic element 6 is referred to as a parasitic side connection point, and a point connected to the powered element 5 via the second feeding unit 7 is referred to as a fed side connection point. The power supply side connection point of the ground plane 2 refers to an electrical connection point with the outer conductor (minus side conductor) of the coaxial cable. The inner conductor of the coaxial cable is electrically connected to the power-supplied element 5.

  The patch antenna element 3 is a plate-like member made of a conductor. The shape of the patch antenna element 3 is a shape in which a cutout portion 31 is provided in a pair of diagonal portions of a square. The notch 31 is a structure for radiating (or receiving) circularly polarized waves, and corresponds to a so-called degenerate separation element or perturbation element. The area of the portion cut from the original square by the notch 31 may be an area determined by a well-known degenerate separation method.

  The patch antenna element 3 is parallel to the ground plane 2 with a predetermined distance D21 (including substantially parallel), and each side of the patch antenna element 3 and each side of the ground plane 2 face each other. Placed in. Here, the side of the patch antenna element 3 indicates a shape when the cutout portion 31 is ignored, that is, an outer peripheral portion corresponding to a side of a square.

A side 32 in FIG. 2 is a side facing the side 21 of the ground plane 2, and a side 33 is a side facing the side 22 of the ground plane 2. The electrical length of one side of the patch antenna element 3 is half the first wavelength, as shown in FIG. Note that λ _{1 in} FIG. 4 represents the wavelength of the first frequency radio wave on the surface of the substrate 1 shortened by the wavelength shortening effect of the substrate 1. The patch antenna element 3 corresponds to the first frequency element recited in the claims.

  In the present embodiment, the patch antenna element 3 is supported by the first feeding portion 4 so as to face the ground plane 2 with a predetermined distance D21 (see FIG. 3). In the present embodiment, since the space between the ground plane 2 and the patch antenna element 3 is made hollow, the first feeding unit 4 serves to supply the high frequency current corresponding to the first frequency to the patch antenna element 3. 2 and the patch antenna element 3 are supported so as to face each other with a predetermined distance D21.

  For example, the first power feeding unit 4 may be a columnar member in which conductive pins that electrically connect the patch antenna element 3 and the inner conductor of the coaxial cable are covered with an electrically insulating material such as resin. Of course, the method of supporting the patch antenna element 3 so as to face the ground plane 2 with a predetermined distance D21 is not limited thereto. By arranging a plate-like member made of an electrically insulating material such as resin and having a predetermined thickness D21 between the patch antenna element 3 and the ground plane 2, the patch antenna element 3 and the ground plane 2 are opposed to each other. You may support.

  The first feeding unit 4 is provided at the center (including the vicinity) of the side 32 facing the longitudinal part of the fed element 5 among the four sides provided in the outer peripheral part of the patch antenna element 3.

  The fed element 5 is a so-called L-shaped monopole conductor element in which a substantially linear monopole conductor element is bent at a right angle (including a substantially right angle) in the middle (a right-angle portion). Hereinafter, the relatively longer part of the two parts, that is, the part from one end part to the right-angle part of the power-supplied element 5 and the part from the other end to the right-angle part is referred to as the longitudinal part 51. The relatively short part is referred to as the short part.

  Of the two ends of the line-fed element 5, the end on the short side is electrically connected to the inner conductor of the coaxial cable. That is, the power-supplied element 5 is connected to the power-supplied-side connection point of the ground plane 2 via the second power-feeding portion 7 at the end on the short side. Here, the connection of the power-supplied element 5 and the ground plane 2 via the second power feeding unit 7 is to electrically connect one end of the power-supplied element 5 to the inner conductor of the coaxial cable, and to connect the power-supplied side of the ground plane 2. It refers to electrically connecting a point with the outer conductor of a coaxial cable. That is, the fed element 5 and the ground plane 2 are in a floating state in terms of direct current.

  The end portion that is not connected to the main plate 2 (that is, the end portion on the longitudinal portion 51 side) is an open end. The power-supplied element 5 corresponds to the second frequency element described in the claims, particularly the power-supplied second frequency element.

  The fed element 5 is disposed on the substrate 1 such that the longitudinal portion 51 faces the outer periphery of the ground plane. More specifically, the power-supplied element 5 has a predetermined interval D22 with respect to the side 21 where the power-feed-side connection point is provided among the four sides where the longitudinal portion 51 forms the outer periphery of the ground plane 2. The power supply side connection point is positioned so as to be positioned closer to the parasitic element 6 than the open end. If the size of the second power feeding unit 7 is ignored, the distance D22 between the long part of the power-supplied element 5 and the ground plane 2 corresponds to the length of the short part of the power-fed element 5. The longitudinal portion 51 corresponds to an example of a second element side facing portion, particularly a powered second element side facing portion described in the claims.

  Here, the range indicated by the substantially parallel means that, as will be described later, of the sides provided in the main plate 2, the range of the desired size is obtained by the current flowing through the longitudinal portion 51 near the side 21 facing the longitudinal portion 51. The range in which the image current is induced. The electrical length of the power-supplied element 5 only needs to be a length that induces an image current of a desired magnitude in the ground plane 2 when a current is passed through the power-supplied element 5. In the present embodiment, an example is given. As a result, it is set to 1/8 of the second wavelength.

  The parasitic element 6 is an L-type monopole conductor element, like the powered element 5. Of the two ends provided in the parasitic element 6, the end on the short side is connected to the ground plane 2 at the parasitic side connection point. The end portion that is not connected to the main plate 2, that is, the end portion on the longitudinal portion 61 side is an open end. The parasitic element 6 corresponds to the parasitic second frequency element recited in the claims.

  The parasitic element 6 is disposed on the substrate 1 such that the longitudinal portion 61 of the parasitic element 6 faces the outer periphery of the ground plane. More specifically, the parasitic element 6 is substantially parallel to the side 22 where the parasitic side connection point is provided, among the four sides whose longitudinal portion 61 forms the outer periphery of the ground plane 2, and The non-feeding side connection point is arranged so as to be located closer to the fed element 5 than the open end.

  The range indicated by the substantially parallel here is a range that satisfies the same relationship as the positional relationship between the longitudinal portion 51 and the side 21. The electrical length of the parasitic element 6 is set to one-eighth of the second wavelength, similarly to the powered element 5. The longitudinal portion 61 corresponds to an example of a second element side facing portion, particularly a parasitic second element side facing portion described in the claims.

  The positional relationship among the ground plane 2, the patch antenna element 3, the fed element 5 and the parasitic element 6 in the overall configuration of the antenna device 100 described above will be summarized. As described above, the longitudinal part 51 of the power-supplied element 5 and the longitudinal part 61 of the parasitic element 6 face each of the two sides 21 and 22 that are perpendicular to each other provided in the ground plane 2. The patch antenna element 3 has a posture in which each side and each side of the ground plane 2 face each other (see FIG. 2).

  That is, of the four sides provided in the patch antenna element 3, the side 32 on the side where the fed element 5 is provided faces the longitudinal portion 51 of the fed element 5. Of the four sides included in the patch antenna element 3, the side 33 on the side where the parasitic element 6 is provided faces the longitudinal portion 61 of the parasitic element 6.

  Hereinafter, for convenience, in the patch antenna element 3, the side 32 facing the longitudinal part 51 of the power-supplied element 5 is referred to as a patch-side facing side, and the side 21 facing the longitudinal part 51 of the power-supplied element 5 in the ground plane 2 is This is called the main plate side facing side. The patch side facing side 32 corresponds to an example of a first element side facing portion recited in the claims, and the ground plane side facing side 21 corresponds to an example of a ground plane side facing portion recited in the claims.

  3 is an enlarged view of the vicinity of the fed element 5 in the cross-sectional view of the antenna device 100 taken along the line III-III shown in FIG. In the figure, D1 is the distance between the fed element 5 and the end of the patch antenna element 3 on the fed element 5 side (the distance between the elements), and D21 is the distance between the ground plane 2 and the patch antenna element 3 ( D22 represents the distance between the power-supplied element 5 and the end of the ground plane 2 on the power-supplied element 5 side (referred to as the second ground plane distance). For example, the inter-element distance D1 is set to 1/50 (about 4 mm) of the second wavelength. Further, the first ground plane distance D21 and the second ground plane distance D22 are each 1 / 100th (about 2 mm) of the second wavelength.

  The size, length, and shape of each part of the antenna device 100 may be designed as appropriate. However, the configuration of the present embodiment is intended to reduce the size of the antenna device that transmits and receives the circularly polarized wave having the first frequency and the circularly polarized wave having the second frequency. Here, in order to reduce the size of the antenna device 100, the inter-element distance D1 is set to be 1/50 of the second wavelength and is very close to each other.

(About transmission and reception of radio waves of the first frequency)
Next, the operation of the antenna device 100 will be described. First, the operation | movement at the time of transmitting / receiving the electromagnetic wave of a 1st frequency is demonstrated using FIG.

  As shown in FIG. 4, the first frequency configuration 101 for transmitting and receiving the circularly polarized wave of the first frequency is the same as the configuration for transmitting and receiving the circularly polarized wave using a known patch antenna. That is, at the time of transmission of radio waves, two currents Ia and Ib that are orthogonal to each other and shifted in phase by 90 ° are excited in the patch antenna element 3 by the power supplied from the first power feeding unit 4. Then, circularly polarized waves (here, right-handed circularly polarized waves) are radiated into the space by the currents Ia and Ib.

  Here, the operation when transmitting the radio wave of the first frequency has been described. However, since it has reversibility of transmission and reception, the circularly polarized wave of the first frequency can also be received by the configuration shown in FIG.

(About transmission and reception of radio waves of the second frequency)
Next, the operation | movement at the time of transmitting / receiving the electromagnetic wave of 2nd frequency is demonstrated using FIG. As shown in FIG. 5, the second frequency configuration 102 for transmitting and receiving the circularly polarized wave of the second frequency includes a ground plane 2, a fed element 5, a parasitic element 6, and a second feeding unit 7.

  As described above, the power-supplied element 5 and the parasitic element 6 are disposed along the sides 21 and 22 of the ground plane 2 that are orthogonal to each other so that the connection portion between the ground plane 2 and the ground plane 2 is close. In other words, the fed element 5 and the parasitic element 6 are arranged such that their longitudinal directions are orthogonal to each other and the open ends are separated from each other.

  The arrangement in which the open ends are separated from each other means that a half line extending from the right-angled portion of the fed element 5 toward the open end does not intersect with a straight line passing through the longitudinal portion 61 of the parasitic element 6 and The arrangement is such that the half line extending from the right-angled portion of the element 6 toward the open end does not intersect with the straight line passing through the longitudinal portion 51 of the fed element 5.

  For convenience, as shown in FIG. 5, the position of the power supply side connection point on the outer peripheral portion of the ground plane 2 is indicated by reference numeral 25, and the position of the non-power supply side connection point is indicated by reference numeral 26. Further, apexes corresponding to both ends of the side 21 where the power-supplied side connection point 25 is provided are A and B, respectively, and apexes corresponding to both ends of the side where the non-feed side connection point 26 is provided are B and C. Side 21 and side 22 share vertex B.

  FIG. 6 is a conceptual diagram for explaining the positional relationship between the power-supplied side connection point 25 and the non-power-supply side connection point 26 on the side 21 and the side 22 of the ground plane 2. As can be seen by comparing FIG. 5 and FIG. 6, in the line segment from vertex A to vertex C in FIG. 6, the section from vertex A to vertex B represents side 21, and from vertex B to vertex C Represents the side 22. The section representing the side 22 and the section representing the side 21 are actually perpendicular.

The fed-side connection point 25 is provided at a position where the distance from the vertex C on the outer periphery of the ground plane 2 is electrically a quarter wavelength of the second wavelength. That is, the sum of the length of the side 22 (= the length of the side 21) and the length from the apex B to the power-supplied side connection point 25 is electrically provided at a position where it is a quarter of the second wavelength. Note that λ _{2 in} FIG. 4 represents the wavelength of the second frequency radio wave (so-called waveguide wavelength) in the ground plane 2 shortened by the wavelength shortening effect by the substrate 1.

  Further, the non-feed side connection point 26 is provided at a position where the distance from the apex A on the outer periphery of the ground plane 2 is electrically a quarter of the second wavelength. That is, the position of the parasitic side connection point 26 is provided at a position where the sum of the length of the side 21 and the length from the apex B to the parasitic side connection point 26 is electrically a quarter of the second wavelength.

  For reference, when the waveguide frequency of the second frequency in the ground plane 2 is about 117 mm, the length of one side of the ground plane 2 is a length corresponding to a quarter of the waveguide wavelength (about 29 mm). For example, it may be set to 25 mm. In that case, the distance from the vertex B to the power-supplied side connection point 25 may be 4 to 5 mm. That is, the sum of the electrical lengths from one side and the vertex B to the fed-side connection point 25 only needs to be a length corresponding to a quarter of the waveguide wavelength.

  In the present embodiment, the electrical length from the vertex C to the power-supplied connection point 25 and the electrical length from the vertex A to the non-power-feeding connection point 26 are each a quarter of the second wavelength. However, the present invention is not limited to this. As another aspect, the electrical length from the vertex C to the fed-side connection point 25 and the electrical length from the vertex A to the non-feed-side connection point 26 are integral multiples of a quarter of the second wavelength. For example, it may be a length corresponding to one-half of the second wavelength or three-fourths.

  Next, the operation of the second frequency configuration 102 having the configuration described above will be described. Since the operation at the time of transmission and the operation at the time of reception of the second frequency configuration 102 have symmetry, the following description will be given taking as an example the case of transmitting a radio wave of the second frequency.

  At the time of transmitting the radio wave of the second frequency, as shown in FIG. 7, a high-frequency current corresponding to the second frequency is supplied from the second power feeding unit 7 to the power-supplied element 5, and the current on the power-supplied element 5 is directed toward the open end. I1 flows. An image current I2 is induced in the vicinity of the outer periphery of the ground plane 2 by the current I1 flowing through the fed element 5. The image current I <b> 2 is induced in a direction from the vertex A toward the parasitic connection point 26 along the side 21.

  Note that the image current can also be induced by the current I1 in the outer peripheral portion of the ground plane 2 in parts other than the side 21 and the side 22, for example, the opposite side of the side 22 of the ground plane 2. However, since the electrical length from the vertex A to the non-feed side connection point 26 is a length corresponding to a quarter wavelength of the target radio wave, the image current I2 is the non-feed side connection point 26 and It is easy to form a standing wave having nodes (or antinodes) at each of the vertices A. Therefore, the image current I2 induced by the current I1 is mainly generated between the apex A and the non-feed side connection point 26. For the above reason, the vertex A can be regarded as the starting point of the image current I2.

  The image current I <b> 2 that flows from the vertex A toward the parasitic connection point 26 flows into the parasitic element 6 from the parasitic connection point 26. The component is referred to as current I3 for convenience. Note that the phase of the current I3 flowing through the parasitic element 6 is such that the electrical length from the apex A to the parasitic connection point 26 is ¼ of the second wavelength. It will be 90 degrees behind.

  Then, when the current I3 is generated on the parasitic element 6, an image current I4 is induced around the side 22 as shown in FIG. The direction of the image current I4 is the direction from the vertex C toward the power supply side connection point 25. Further, the phase of the image current I4 is delayed by 90 degrees with respect to the image current I2.

  The reason why the image current I4 is generated mainly from the vertex C to the fed-side connection point 25 is that the electrical length from the vertex C to the fed-side connection point 25 is ¼ of the second wavelength. This is because. That is, the image current I4 is generated between the vertex C and the power-supplied side connection point 25 due to the stability in the resonance state. Here, the stability of the resonance state refers to the ease of forming a standing wave node.

  In the section from the non-feed side connection point 26 to the fed side connection point 25, the image current I2 and the image current I4 overlap. Since the image current I2 and the image current I4 are currents in opposite directions, they behave so as to cancel each other.

  FIG. 9 summarizes the operation of the second frequency configuration 102 described above. Between the vertex A of the ground plane 2 and the power supply side connection point 25, an image current I2a caused by the current I1 flowing through the power supplied element 5 flows. In addition, an image current I4a whose phase is delayed by 90 degrees with respect to the image current I2a flows between the vertex C of the ground plane 2 and the non-feed side connection point 26. Further, the sides 21 and 22 where the image currents I2a and I4a are generated are at right angles as shown in FIG.

  That is, the image currents I2a and I4a are orthogonal to each other and are 90 degrees out of phase. In addition, since the amplitude of the current is approximately the same, circular polarization of the second frequency is transmitted by these image currents I2a and I4a.

  The circularly polarized wave having the second frequency is radiated in a direction perpendicular to the ground plane 2. That is, the circularly polarized wave radiated by the second frequency configuration 102 is radiated in the direction in which the patch antenna element 3 exists.

(About the interaction between the first frequency configuration 101 and the second frequency configuration)
When transmitting circularly polarized waves of the second frequency, a current flows through the fed element 5. The patch antenna element 3 generates an electric field Eb as shown in FIG. An electric field Eb in FIG. 10 represents an electric field generated in the vicinity of the patch-side facing side 32 in the patch antenna element 3.

  Of course, the patch antenna element 3 generates an electric field not only in the vicinity of the patch side facing side 32 but also in other regions. The electric field generated in the patch antenna element 3 is attenuated in amplitude and delayed in phase as the distance from the powered element 5 increases. That is, the electric field generated in the patch antenna element 3 is strongest in the vicinity of the patch-side facing side 32 and becomes weaker as the distance from the powered element 5 increases.

  Further, an electric field Ea is also generated on the ground plane 2 as shown in FIG. An electric field Ea in FIG. 10 represents an electric field generated in the vicinity of the ground plane side facing side 21 in the ground plane 2. Similarly to the patch antenna element 3, the electric field generated in the ground plane 2 has a maximum amplitude in the vicinity of the ground plane side facing side 21, and an electric field distributed so that the amplitude decreases as the distance from the fed element 5 increases.

  Incidentally, in order to reduce the size of the antenna device 100, the fed element 5, the ground plane 2, and the patch antenna element 3 are very close to the second wavelength. More specifically, the inter-element distance D1 is about 1/50 of the second wavelength, and the first ground plane distance D21 and the second ground plane distance D22 are also about 1/100 of the second wavelength. Yes.

  That is, the fed element 5, the ground plane 2, and the patch antenna element 3 are very close to the second wavelength, respectively, and the first ground plane distance D 21 is also very close to the second wavelength. It is a small value.

  For this reason, the electric field Ea generated in the vicinity of the ground side opposing side 21 and the electric field Eb generated in the vicinity of the patch side opposing side 32 have substantially the same amplitude and phase. Here, “substantially the same” means that the difference can be ignored.

  Therefore, when the first power feeding unit 4 is installed in the vicinity of the patch-side facing side 32, for example, at the position indicated by P1 in FIG. 10, the difference in amplitude between the electric field of the patch antenna element 3 and the electric field of the ground plane 2 Since the phase difference is small, it is difficult for current to flow through the pins of the first power feeding unit 4. The vicinity here means a range in which the amplitude difference and the phase difference from the electric field of the ground plane 2 are small, and the radiation characteristic of the radio wave of the second frequency is not deteriorated by the current flowing through the pin of the first power feeding unit 4. do it.

  On the other hand, the distance between the phase and amplitude of the electric field generated in the ground plane 2 and the phase and amplitude of the electric field generated in the patch antenna element 3 increase as the distance from the powered element 5 increases. For example, when the first power feeding unit 4 is provided at the position P2, the amplitude and phase shift of the electric field between the patch antenna element 3 and the ground plane 2 is larger than when the first power feeding unit 4 is provided at P1, and the current is supplied to the first power feeding unit 4. Is easy to flow. That is, for example, when the first power feeding unit 4 is provided at a position away from the power-supplied element 5 such as P2, a current flows through the first frequency component 101, and the radiation characteristic of the radio wave of the second frequency is reduced. It will deteriorate.

  In view of the above, the antenna device 100 installs the first feeding unit 4 in the vicinity of the side 32 of the patch antenna element 3 that faces the fed element 5. According to such a configuration, it is possible to suppress the current flowing through the first power feeding unit 4 when transmitting and receiving radio waves of the second frequency. That is, according to such a configuration, it is possible to achieve both the size reduction of the antenna device 100 and the isolation in the radio wave of the second frequency.

  The conditions under which electric fields having the same amplitude and the same phase are generated in the vicinity of the patch-side facing side 32 and in the vicinity of the ground plane-side facing side 21 by the current flowing through the power-supplied element 5 are not limited to the above-described design values. When the distances D1 and D22 between the longitudinal portion 51 of the power-supplied element 5 and the patch-side facing side 32 and the ground-plate-side facing side 21 are within 1 / 25th of the second wavelength, It is assumed that the electric currents Ea and Eb that can be regarded as having the same amplitude and the same phase are generated in the vicinity of the patch side facing side 32 and in the vicinity of the ground plane side facing side 21 due to the current flowing through the element 5.

  Of course, as the distance between the three elements is smaller, the amplitudes and phases of the electric fields Ea and Eb generated in the vicinity of the patch-side facing side 32 and in the vicinity of the ground plane-side facing side 21 become equal. Then, as the first power feeding unit 4 is provided closer to the patch-side facing side 32, current due to the difference in electric field is less likely to flow, and isolation can be improved.

  Therefore, from the viewpoint of ensuring isolation, the first power supply unit 4 passes through the central portion Pc of the patch antenna element 3 and is closer to the element to be fed 5 than the straight line L2 parallel to the longitudinal part 51 of the power feed element 5. It is preferable to provide in. The central portion Pc here indicates a point-symmetric center of the patch antenna element 3.

  However, the position of the 1st electric power feeding part 4 may be provided in the position which shifted | deviated from the patch side opposing edge 32 to the center part side from a viewpoint of matching impedance with a coaxial cable besides isolation.

  Further, in the present embodiment, the first feeding portion 4 is parallel to the longitudinal portion 61 of the parasitic element 6 through the central portion Pc of the patch antenna element 3 so that the first frequency configuration 101 operates more preferably. Although the example provided on the straight line L1 was described, it is not restricted to this. The 1st electric power feeding part 4 may be provided in the position P3 approached to the parasitic element 6 side a little from the straight line L1.

  The interaction between the first frequency configuration 101 and the second frequency configuration when transmitting the second frequency circular polarization has been described above, but the same applies when receiving the second frequency circular polarization. is there.

  In the above configuration, the current flowing through the second power feeding unit 7 when transmitting / receiving the radio wave of the first frequency is a negligible value (a value within an allowable range). This is mainly because the inter-element distance D1, the first ground plane distance D21, and the second ground plane distance D22 are sufficiently long for the first wavelength (50 mm), and the first frequency component 101 is relatively narrow. This is because the frequency characteristics are in a band. The isolation between the first frequency configuration 101 and the second frequency configuration 102 at the first frequency is a sufficiently small value regardless of the position of the first power feeding unit 4.

(Effect of this embodiment)
Hereinafter, the comparative configuration 100X shown in FIG. 11 will be introduced, and the effects of the antenna device 100 in this embodiment will be described. In the comparative configuration 100X shown in FIG. 11, the position of the first feeding unit 4 is the opposite side of the patch-side facing side 32 among the sides of the patch antenna element 3, that is, the central portion of the side farthest from the fed element 5. It is the structure provided in.

  FIG. 12 shows the result of comparing the isolation with respect to the radio waves of the second frequency in the respective configurations of the comparative configuration 100X and the antenna device 100 of the present embodiment. Here, the isolation (unit: dB) with respect to the second frequency radio wave is the power input to the second frequency radio frequency 102 when the second frequency radio wave 102 is radiated. And the magnitude of the ratio of the power returned from the first frequency configuration 101.

  The solid line shown in FIG. 12 indicates the isolation of the second frequency radio wave in the antenna device 100 according to the present embodiment, and the broken line indicates the isolation of the second frequency radio wave in the comparative configuration 100X. Here, since the GPS radio wave is assumed as the radio wave of the second frequency, the horizontal axis represents a value centering on 1.575 GHz where the GPS radio wave is used.

  As shown in FIG. 12, the comparison configuration 100X has a value of −7 to 8 dB at any frequency, whereas according to the configuration of the present embodiment, the inter-element distance D1 is set to the second wavelength. Isolation can be suppressed to about -15 db even if it is made close to 1/50 of.

  FIG. 13 is a diagram illustrating a result of comparing the axial ratios of the circularly polarized waves of the second frequency in the configurations of the comparative configuration 100X and the antenna device 100 of the present embodiment. In general, when isolation is degraded, the axial ratio of circularly polarized waves is also degraded. In addition, it shows that circular polarization becomes an ellipse, so that an axial ratio is large. The horizontal axis indicates the frequency as in FIG.

  As shown in FIG. 13, in the comparative configuration 100X, the axial ratio is 3 or more even in the minimum value that protrudes downward, whereas in the configuration of this embodiment, the minimum value is less than 1. can do.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, The following modification is also contained in the technical scope of this invention, Furthermore, the summary other than the following is also included. Various modifications can be made without departing from the scope.

  In the above description, 5.8 GHz is adopted as the first frequency and 1.5 GHz is adopted as the second frequency. Of course, the combination of the first frequency and the second frequency is not limited to these. Other frequencies may be the first frequency or the second frequency.

  The inter-element distance D1 is not limited to 1/50 of the second wavelength, but may be a value of 1/50 or less, such as 1/100, or 1/50, or 1/50. It may be the above value. That is, the inter-element distance D <b> 1 only needs to be a distance that generates an electric field that can be regarded as having the same amplitude and the same phase on the ground plane side facing side 21 and the patch side facing side 32. Similarly, the first ground plane distance D21 and the second ground plane distance D22 may be appropriately changed. For example, the first ground plane distance D21 may be a length corresponding to 1/50 of the second wavelength.

<Modification 1>
In the above-described embodiment, both the first frequency configuration 101 and the second frequency configuration 102 are provided on the front side of the substrate 1. However, the present invention is not limited to this. The first frequency component 101 may be disposed on the front surface of the substrate 1 and the second frequency component 102 may be disposed on the back surface. Further, in such a configuration, the ground plane 2 may be shared by the first frequency configuration 101 and the second frequency configuration 102 as in the embodiment, and members corresponding to different ground planes 2 may be used as the surface. You may arrange | position on the both sides of a back surface.

<Modification 2>
In the above, the configuration in which the position where the first power feeding unit 4 is provided is illustrated in the vicinity of the side 32 of the patch antenna element 3 that faces the power-supplied element 5, but is not limited thereto.

  In the second frequency configuration 102, the fed element 5 and the parasitic element 6 operate symmetrically as shown in FIG. Therefore, even if the first power feeding section 4 is provided in the vicinity of the side 33 facing the parasitic element 6 in the patch antenna element 3 as shown in FIG. 14, the same effects as in the above-described embodiment can be obtained.

  In the antenna device 100A according to the second modification, the first feeding unit 4 is preferably arranged on the parasitic element 6 side with respect to the straight line L1 from the viewpoint of ensuring isolation, and in particular, the patch antenna element 3 The configuration in which the first power feeding unit 4 is provided in the vicinity of the side facing the parasitic element 6 is most preferable. Of course, from the viewpoint of maintaining the axial ratio of the circularly polarized wave of the first frequency, it is preferable that the first power feeding unit 4 is disposed on the straight line L2. What is necessary is just to adjust the actual position of the 1st electric power feeding part 4 suitably so that the impedance matching with a coaxial cable can be taken.

<Modification 3>
In addition, the configuration based on a shape such as a square or a rectangle is exemplified as the shape of each part (for example, the ground plane 2 and the patch antenna element 3) provided in the antenna device. However, the shape of each part constituting the antenna device is not limited to a shape such as a square or a rectangle. Furthermore, it is not limited to polygons such as hexagons and octagons. For example, you may deform | transform into the structure based on circular (an ellipse is included) (this is set as the modification 3).

  As shown in FIG. 15, the antenna device 100B in Modification 3 includes a circular substrate (not shown), a ground plane 2B, a patch antenna element 3B, a first feeding unit 4B, a fed element 5B, a parasitic element 6B, The 2nd electric power feeding part 7B is provided.

  The ground plane 2B, the patch antenna element 3B, the first feeding part 4B, the fed element 5B, the parasitic element 6B, and the second feeding part 7 are in the order described, respectively, in the order described in the ground plane 2, the patch antenna element 3, the first This corresponds to the one power feeding unit 4, the power fed element 5, the parasitic element 6, and the second power feeding unit 7.

  That is, the configuration including the ground plane 2B, the patch antenna element 3B, and the first feeding unit 4B is a configuration for transmitting and receiving circularly polarized waves of the first frequency, and includes the ground plane 2B, the fed element 5B, the parasitic element 6B, And the structure which consists of 2nd electric power feeding part 7B is corresponded to the structure which transmits / receives the circularly polarized wave in a 2nd frequency.

  Even in such a configuration, the first feeding portion 4B is provided in the vicinity of the portions 32B and 33B facing the longitudinal portion 51B of the fed element 5B or the longitudinal portion 61B of the parasitic element 6B on the outer periphery of the patch antenna element 3B. Thus, isolation at the second frequency can be suppressed.

  In addition, the part pointed by 21B and 22B among the outer peripheral parts of the base plate 2B is a part facing the longitudinal part 51B, that is, a part corresponding to the base plate side facing side in the embodiment.

<Modification 4>
Furthermore, in the above, the antenna device 100 that employs a configuration for transmitting and receiving circularly polarized waves using the fed element 5 and the parasitic element 6 is illustrated as a configuration for transmitting and receiving the radio wave of the second frequency. Not exclusively.

  The configuration for transmitting and receiving radio waves of the second frequency may be one that transmits and receives linearly polarized waves. An example of such a configuration (referred to as Modification 4) is shown in FIG.

  An antenna device 100C illustrated in FIG. 16 includes a fed element 5C that is an L-type monopole conductor element, and a fed element 5C in place of the fed element 5, the parasitic element 6, and the second feeding unit 7 in the embodiment. A second power supply unit 7C for supplying power to the power supply. The electrical length of the fed element 5C is a quarter of the second wavelength, and the same structure as a known monopole antenna is provided by the fed element 5C, the ground plane 2, and the second feeding unit 7C. It has become.

  It is assumed that the longitudinal portion of the fed element 5C is substantially parallel to one side of each of the ground plane 2 and the patch antenna element 3, similarly to the longitudinal portion of the fed element 5 in the embodiment. For convenience, the side facing the longitudinal part of the fed element 5C in the ground plane 2 and the side facing the longitudinal part of the fed element 5C in the patch antenna element 3 are respectively opposed to the ground plane side as in the embodiment. The side is referred to as the patch side facing side.

  Also in the configuration shown in Modification 4, by providing the first power feeding unit 4 in the vicinity of the patch-side facing side, the longitudinal portion of the power-supplied element 5C, the ground-plate-side facing side, and the patch-side facing side are close to each other. Even if it is a case, the isolation with respect to the electromagnetic wave of a 2nd frequency can be reduced.

  In the modification 4, the configuration for transmitting (and receiving) the radio wave of the second frequency with the linearly polarized wave has been described, but the configuration for transmitting and receiving the radio wave of the first frequency is not circularly polarized as well, You may transmit and receive by a linearly polarized wave. That is, the patch antenna element 3 may be configured not to include the notch 31.

100, 100A / 100B / 100C antenna device, 101 first frequency configuration, 102 second frequency configuration, 1 substrate, 2 / 2B ground plane (conductor ground plane), 3 / 3B patch antenna element (first frequency element), 4 · 4B 1st feeding section, 5 · 5B · 5C Feeded element (second frequency element, fed second frequency element), 6 · 6B Parasitic element (second frequency element, parasitic second frequency) Element), 7 · 7B · 7C second feeding portion, 21 · 21B · 22 · 22B ground plane side facing side (ground plate side facing portion), 32 · 33 patch side facing side (first device side facing portion)

Claims (6)

A conductor ground plane (2);
A first frequency element (3, 3B) which is an element for performing at least one of transmission and reception of radio waves of the first frequency, and is disposed to face the conductor ground plane with a predetermined interval. )When,
A first power feeding section (4, 4B) for electrically connecting the first frequency element and a power feeding line;
A second frequency element (5, 5B, 5C, 6, 6B) that is a linear element for performing transmission and reception of radio waves having a second frequency lower than the first frequency. ,
The second frequency element is provided on the outside of the conductor ground plane, and faces the second element side facing a part of the outer periphery of the conductor ground plane and a part of the outer periphery of the first frequency element. Part (51, 51B, 51C, 61, 61B),
The conductor ground plane is an outer peripheral portion facing the second element side facing portion, and is a portion closest to the second element side facing portion in the conductor ground plane (21, 21B, 22 and 22B)
The first frequency element is a first element that is an outer peripheral part facing the second element side facing part and is a part closest to the second element side facing part in the first frequency element. With side facing parts (32, 32B, 33, 33B),
With respect to the second element side facing portion, each of the conductor ground plane and the first frequency element is caused to flow into the ground plane side facing portion and the first element side facing portion by a current flowing through the second frequency element. It is a position where electric fields with substantially the same amplitude and phase are generated,
The antenna device according to claim 1, wherein the first power feeding unit is provided closer to the first element side facing portion than the center of the first frequency element. In claim 1,
The distance between the second element side facing portion and the first element side facing portion and the distance between the second element side facing portion and the ground plane side facing portion are both 25 of the wavelength of the radio wave of the second frequency. An antenna device characterized in that the antenna device is less than one part. In claim 2,
The antenna device, wherein an interval between the conductor ground plane and the first frequency element is 1/50 or less of the wavelength of the radio wave of the second frequency. In any one of Claims 1-3,
The first frequency element has a square shape including a perturbation element (31) for transmitting and receiving circularly polarized waves,
The antenna device, wherein the first frequency element, the first feeding portion, and the conductive ground plane are configured to operate as a patch antenna capable of transmitting and receiving a circularly polarized wave having a first frequency. In claim 4,
The antenna device as the second frequency element,
A fed second frequency which is a linear element, one end of which is connected to the conductor ground plane via a second feeding portion (7) for feeding the element, and the other end is an open end. Element (5),
A parasitic second frequency element (6) which is linear and has one end connected to the conductor ground plane and the other end connected to the conductor ground plane;
The conductor ground plane has a square shape,
The power-supplied second frequency element, the non-powered second frequency element, and the conductor ground plane are arranged in the same plane,
The power-supplied second frequency element includes a power-supplied second element side facing portion facing the outer periphery of the conductor ground plane,
The parasitic second frequency element includes a parasitic second element side facing portion that is opposed to the conductor base plate and the outer periphery and orthogonal to the fed second element side facing portion,
The connection portion between the second power feeding portion and the conductor ground plane is provided on the parasitic second frequency element side of the open second end of the powered second frequency element, and the parasitic second frequency is provided. The antenna device is characterized in that the connection portion between the element for use and the conductor ground plane is provided closer to the element to be fed second frequency than the open end of the element. In claim 5,
The first frequency element is provided on one side (surface) of a substrate (1) made of a dielectric material,
The antenna device, wherein the fed second frequency element, the parasitic second frequency element, and the conductive ground plane are provided on a back surface of the substrate.

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