JP6408620B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device.

  Patent Document 1 describes a film antenna including a ground plate and a radiating element formed on the surface of a dielectric substrate (see FIG. 3 of Patent Document 1).

  A film antenna including a radiating element constituted by a plurality of sub-elements having different lengths is known. Such a film antenna operates at a plurality of resonance frequencies corresponding to the lengths of the plurality of sub-elements. Specifically, a longer radiating element bears an operating band on the low frequency side, and a shorter radiating element bears an operating band on the high frequency side. Therefore, such a film antenna can broaden the operating band.

  As a demand for such a film antenna, it is possible to reduce the space required for mounting the film antenna. When the space required for mounting the film antenna is narrowed, it is preferable to employ a flexible substrate having flexibility as the dielectric substrate, and a conductor foil as the ground plate and the radiation element. Since such a film antenna can be bent, it can be mounted in a narrow space.

JP 2007-235404 A (published September 13, 2007)

  However, it is necessary to increase the size of such a film antenna in order to improve the low frequency characteristics.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce the size of an antenna device having a low-frequency side operation band and a high-frequency side operation band without increasing the size of the antenna device. It is to expand the operating band on the frequency side.

  In order to solve the above problem, an antenna device according to an aspect of the present invention includes a first surface, a second surface intersecting the first surface, the first surface direction, and the first surface. A support that includes a third surface that intersects the second surface and is spaced apart from the first surface; (1) a first member having a first resonance frequency and disposed along the first surface; 1 radiating element, (2) a first region having a second resonance frequency higher than the first resonance frequency and disposed along the second surface, and the first And a second radiating element including a second region disposed along a plane of the third antenna, wherein the first radiating element extends in a direction approaching the second plane. When the first radiating element is included in a plan view, the sub-element partially or entirely overlaps the second region. And features.

  The antenna device includes a first radiating element having a first resonance frequency and a second radiating element having a second resonance frequency higher than the first resonance frequency. Therefore, the operating band of the antenna apparatus is mainly composed of a low-frequency side operating band in which the first radiating element is responsible for radiation and a high-frequency side operating band in which the second radiating element is mainly responsible for radiation.

  In the antenna of the antenna device, the first radiating element is disposed along the first surface of the support, and the second radiating element is disposed along the second surface and the third surface of the support. In other words, the antenna is arranged in a state of being bent with respect to the support so as to cover the first surface, the second surface, and the third surface of the support. Therefore, the antenna device is more compact than a case where the antenna is provided in a deployed state.

  Further, since the sub-element provided in the first radiating element is provided so as to overlap with the second region of the second radiating element, the operation band that the first radiating element takes, that is, the operation on the low frequency side. The band can be shifted to the low frequency side. Therefore, by including this sub-element, the present antenna device can expand the operating band on the low frequency side to the low frequency side.

  Thus, this antenna device can expand the operating band on the low frequency side without increasing the size.

  According to one embodiment of the present invention, in an antenna device having a low-frequency operation band and a high-frequency operation band, the low-frequency operation band can be expanded without increasing the size of the antenna device.

FIG. 2A is an exploded perspective view of an antenna device according to an embodiment of the present invention. (B) is a top view at the time of planarly seeing the radiation element with which the antenna apparatus shown to (a) is provided from the z-axis negative direction side. It is an expanded view of the antenna with which the antenna apparatus which concerns on embodiment of this invention is provided. (A) is a perspective view of the vehicle body which mounts the vehicle-mounted antenna apparatus provided with the antenna apparatus shown in FIG. (B) is a top view of the vehicle-mounted antenna device shown in (a). It is an expanded view of the antenna with which the antenna apparatus which is an Example of this invention is provided. It is a graph which shows the measurement result of the frequency dependence of VSWR of the antenna apparatus which is an Example of this invention.

  An antenna device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1A is an exploded perspective view of the antenna device 1 according to the present embodiment. FIG. 1B is a plan view of the radiating element 11 included in the antenna device 1 shown in FIG. 1A when viewed in plan from the z-axis negative direction side of the coordinate axis shown in FIG. is there. FIG. 2 is a development view of the antenna 10.

  The antenna 10 is an antenna assumed to operate in a frequency band for LTE (Long Term Evolution). The LTE frequency band is composed of a frequency band on the low frequency side from 698 MHz to 960 MHz and a frequency band on the high frequency side from 1.4 GHz to 2.6 GHz.

  Therefore, the antenna device 1 is composed of the operating band on the low frequency side and the operating band on the high frequency side, covers the frequency band in which the operating band on the low frequency side is 698 MHz to 960 MHz, and operates on the high frequency side. The band is designed to cover a frequency band of 1.4 GHz to 2.6 GHz. However, the present invention can also be applied to an antenna device having an operating band different from the above-described operating band. The operating band of the antenna device according to the embodiment of the present invention can be variously changed by adjusting the patterns of the first radiating element and the second radiating element.

(Configuration of antenna device 1)
As shown in FIG. 1A, the antenna device 1 includes an antenna 10, a coaxial cable 20, and a support body 30. In FIGS. 1A and 1B, the substrate 14 provided in the antenna 10 is not shown, and in FIG. 1B, the support 30 is not shown. .

<Support 30>
In the present embodiment, the support 30 is a block-shaped resin member. As shown in FIG. 1A, the support 30 includes a wall 31, a wall 32, a wall 33, a wall 34, a wall 35, and a wall 36. The surface of the wall 31 is the first surface described in the claims. The surface of the wall 32 is a 2nd surface as described in a claim. The surface of the wall 33 is the third surface described in the claims.

  In the present embodiment, a connection region 37 made of a smooth curved surface is provided between the wall 31 and the wall 32. Similarly, a connection region 38 having a smooth curved surface is provided between the wall 32 and the wall 33. The connection regions 37 and 38 are provided in order to prevent a tight crease from being generated in the antenna 10 when the antenna 10 is wound around the support 30 as will be described later. The connection regions 37 and 38 can be omitted.

  Further, the support 30 is formed with a gap (not shown in FIG. 1A) that leads to the outside of the support 30 from a portion corresponding to a power supply region Rf described later. Can be accommodated.

<Antenna 10>
As shown in FIG. 2, the antenna 10 includes a radiating element 11 that is a first radiating element, a radiating element 12 that is a second radiating element, and a substrate 14.

  The substrate 14 is a flexible and bendable resin film (in this embodiment, a polyimide resin film). The substrate 14 is formed in a rectangular shape. The direction along the pair of long sides constituting the substrate 14 (the y-axis direction in the coordinate system shown in FIG. 2) is called the longitudinal direction of the antenna 10, and the direction along the pair of short sides constituting the substrate 14 (The x-axis direction in the coordinate system illustrated in FIG. 2) is referred to as the width direction of the antenna 10.

  Each of the radiating element 11 and the radiating element 12 is a conductor pattern in which a conductor foil (in this embodiment, a copper foil) is formed into a predetermined pattern. The radiating element 11 and the radiating element 12 are both formed on one surface of the substrate 14. Each of the radiating element 11 and the radiating element 12 has flexibility. Therefore, the antenna 10 is a foldable film antenna.

  As shown in FIG. 2, the substrate 14 is divided into a region 141 and a region 142 with a straight line AA along the width direction as a boundary line. The straight line AA is provided such that the length of the region 141 in the longitudinal direction is longer than the length of the region 142 in the longitudinal direction. Further, the element length L1 and width W1 of the radiating element 11 and the element length L2 and width W2 of the radiating element 12 are defined as shown in FIG.

  Which part the element lengths L1 and L2 indicate will be described later. In the present embodiment, the element length L1 is determined so that the first resonance frequency that is the resonance frequency of the radiating element 11 is 660 MHz. The element length L2 is determined so that the second resonance frequency that is the resonance frequency of the radiating element 12 is 1400 MHz.

  The radiating element 11 is provided so as to occupy most of the region 141. The radiating element 11 includes a distal end portion 111, a connection portion 112, and a main body portion 113. In addition, a parasitic element group 13 including four parasitic elements 131 to 134 surrounding the distal end portion 111 is disposed around the distal end portion 111. Among these configurations, the description of the distal end portion 111, the connection portion 112, and the parasitic element group 13 is omitted.

  The shape of the main body 113 is based on a rectangular conductive foil, and is obtained by cutting out several regions of the conductive foil from the rectangular conductive foil.

  First, of the pair of long sides and the pair of short sides constituting the main body 113, the central portion of the short side on the side close to the straight line AA (the y-axis negative direction side) is cut into a rectangular shape.

  An L-shaped notch 1131 is provided on one long side (long side on the x-axis negative direction side) of the pair of long sides in the width direction of the main body 113. The notch 1131 is cut from one long side along the y-axis direction toward the positive x-axis direction and then cut toward the positive y-axis direction.

  As a result, the main body 113 is extended along the longitudinal direction of the antenna 10 in the direction from the tip of the radiating element 11 toward the feeding region Rf (the negative y-axis direction in the coordinate system illustrated in FIG. 2). A sub-element 1132 is formed. Therefore, the radiating element 11 includes a sub-element 1132.

  The electrical length of the sub-element 1132 is shorter than the electrical length corresponding to the element length L1 of the radiating element 11, and longer than the electrical length corresponding to the element length L2 of the radiating element 12. Therefore, the resonance frequency of the sub-element 1132 is a third resonance frequency that is higher than the first resonance frequency and lower than the second resonance frequency when the antenna 10 is deployed.

  In the present embodiment, the length L3 of the sub-element 1132 and the width W3 of the notch 1131 (see FIG. 2) are determined so that the third resonance frequency is 780 MHz when the antenna 10 is deployed. Accordingly, the third resonance frequency is included in the frequency band on the low frequency side.

  An L-shaped notch 1133 is provided on the other long side (long side on the x-axis positive direction side) of the pair of long sides in the width direction of the main body 113. The notch 1133 is cut from the other long side along the y-axis direction toward the negative x-axis direction and then cut toward the positive y-axis direction.

  As a result, the main body 113 is extended along the longitudinal direction of the antenna 10 in the direction from the tip of the radiating element 11 toward the feeding region Rf (the negative y-axis direction in the coordinate system illustrated in FIG. 2). A sub-element 1134 is formed. Therefore, the radiating element 11 includes a sub-element 1134.

  The electrical length of the sub-element 1134 is shorter than the electrical length corresponding to the element length L1 of the radiating element 11, and longer than the electrical length corresponding to the element length L2 of the radiating element 12. Therefore, the resonance frequency of the sub-element 1134 is a fourth resonance frequency that is higher than the first resonance frequency and lower than the second resonance frequency. In the present embodiment, the length L4 of the sub-element 1134 and the width W4 of the notch 1133 (see FIG. 2) are determined so that the fourth resonance frequency is 950 MHz when the antenna 10 is deployed. Accordingly, the fourth resonance frequency is included in the frequency band on the low frequency side.

  Further, by providing the notch 1131 and the notch 1133, a neck portion 1135 and a root portion 1136 are formed in the main body portion 113. The width of the neck portion 1135 is narrower than the width of the root portion 1136. In addition, the power supply region Rf is included in the root portion 1136.

  The main body 113 of the radiating element 11 is provided with a triangular opening 1137 and a rectangular opening 1138. Each of the opening 1137 and the opening 1138 is provided at the rear stage of the neck portion 1135 when viewed from the power feeding region Rf side along the longitudinal direction.

  On the other hand, the radiating element 12 is provided so as to occupy most of the region 142, and a part of the short side close to the straight line AA protrudes in a rectangular shape. This protruding portion is referred to as a power feeding unit 121. The power feeding unit 121 is formed in a size that is slightly smaller than a portion of the radiating element 11 cut into a rectangular shape. The electric power feeding part 121 is arrange | positioned so that the outline of the said part cut out may be followed, and it may space apart from the said part cut off.

  A coaxial cable 20 for feeding power to the antenna 10 is connected to the feeding portion 121 and the vicinity of the cut-out portion of the radiating element 11. Specifically, the central conductor constituting the coaxial cable 20 is soldered to the power feeding part 121, and the outer conductor constituting the coaxial cable 20 is soldered in the vicinity of the cut portion of the radiating element 11. . Therefore, in the present embodiment, the radiating element 11 is a cold-side radiating element, and the radiating element 12 is a hot-side radiating element.

  A point (or region) where the central conductor is soldered to the power feeding portion 121 is referred to as a hot-side connection point Ph, and a point (or region) where the outer conductor is soldered to the radiating element 11 is referred to as a cold-side connection point Pc. Call. A region including the connection point Ph and the connection point Pc is referred to as a power supply region Rf of the antenna 10.

  The coaxial cable 20 is an aspect of the power supply cable, and the power supply cable of the antenna 10 is not limited to the coaxial cable.

  In the antenna 10 configured as described above, the element length L1 that is the distance from the connection point Pc of the radiating element 11 to the tip of the radiating element 11 is the distance from the connection point Ph of the radiating element 12 to the tip of the radiating element 12. It is longer than a certain element length L2. Therefore, the resonance frequency (first resonance frequency) of the radiating element 11 is lower than the resonance frequency (second resonance frequency) of the radiating element 12. That is, the second resonance frequency is higher than the first resonance frequency.

<How to wrap>
As shown in FIG. 1A, the antenna 10 is supported so that the radiating element 11 is along the surface of the wall 31 and the radiating element 12 is along the surface of the wall 32 and the surface of the wall 33. It is wound around the body 30 (see FIG. 1A). In other words, the antenna 10 is wound around the support 30 so that the straight line AA shown in FIG. 2 is included in the connection region 37 that connects the wall 31 and the wall 32. Therefore, the tip of the radiating element 12 (the position of the straight line CC shown in FIG. 2) is (1) when the radiating element 11 is viewed in plan as shown in FIG. 1B, the straight line DD shown in FIG. (2) When the wall 34 of the support 30 is viewed in plan, it moves to a position separated from the straight line DD shown in FIG.

  As a result, the region of the radiating element 12 other than the power feeding unit 121 is divided into a region 122 that is the first region and a region 123 that is the second region on the ridgeline between the wall 32 and the wall 33. The region 122 is a region arranged along the surface of the wall 32. The region 123 is a region arranged along the surface of the wall 33.

  A straight line BB shown in FIG. 2 indicates the position of the ridgeline between the wall 32 and the wall 33 when the antenna 10 is wound around the support 30 and is included in the connection region 38. The distance between the straight lines AA and BB shown in FIG. 2 corresponds to the thickness of the support 30 (the distance between the surface of the wall 31 and the surface of the wall 33).

  As a result of being wound around the support 30, the shape of the antenna 10 is in the state shown in FIG. FIG. 1B is a plan view of the antenna device 1 configured as described above from the region 123 side of the radiating element 12, that is, from the z-axis negative direction side of the coordinate axis shown in FIG. It is a top view obtained in the case. When viewed in plan from the region 123 side, the sub-elements 1132 arranged along the surface of the wall 31 overlap the region 123 arranged along the surface of the wall 33. That is, the sub element 1132 and the region 123 constitute an overlapping region R1 that is opposed to each other and overlaps. In the present embodiment, the sub element 1132 is configured such that a part including the tip thereof overlaps the region 123. However, the configuration of the sub-element 1132 is not limited to this, and the sub-element 1132 may be configured so that the entire sub-element 1132 overlaps the region 123.

  The antenna 10 is wound around a support so that the surface on the side to which the coaxial cable 20 is connected (the surface on the side where the radiating element 11 and the radiating element 12 are provided) is on the inside. The coaxial cable 20 is accommodated in a gap provided inside the support 30 and is drawn out of the support 30.

  In FIG. 1A, the radiating element 11 is positioned on the upper side (z-axis positive direction side in the coordinate axis shown in FIG. 1), and the region 123 is positioned on the lower side (z-axis negative direction side). Further, the antenna device 1 is arranged. However, the antenna device 1 can operate regardless of the orientation in the space. Therefore, the direction in which the antenna device 1 is arranged in operation is not limited to the state shown in FIG.

  In addition, as a fixing means for fixing the antenna 10 to the support 30, an adhesive tape represented by a double-sided tape, an adhesive, a screw, or the like may be appropriately employed. In the present embodiment, the antenna 10 is fixed to the support 30 using a double-sided tape. Further, the support 30 may be provided with a protrusion for determining the position of the antenna 10 with respect to the support 30 at a predetermined position.

  Since the antenna 10 is fixed to the support 30 in this way, the three-dimensional shape of the antenna 10 does not change from a predetermined shape. Therefore, the radiation characteristics of the antenna device 1 are stable with little fluctuation.

(Effect of sub-element 1132)
As described above, the antenna device 1 includes the radiating element 11 having the first resonance frequency and the radiating element 12 having the second resonance frequency higher than the first resonance frequency. Therefore, the operating band of the antenna device 1 mainly includes a low-frequency side operating band in which the radiating element 11 is responsible for radiation and a high-frequency side operating band in which the radiating element 12 is primarily responsible for radiation.

  Further, the antenna 10 includes a sub-element 1132. The resonance frequency of the sub-element 1132 is a third resonance frequency when the antenna 10 is deployed. However, as shown in FIG. 1B, when the antenna 10 is folded and the sub-element 1132 and the region 123 of the radiating element 12 overlap, the resonance frequency of the sub-element 1132 becomes the third resonance frequency. Shift to about 200MHz from the low frequency side. That is, the resonance frequency of the sub-element 1132 is approximately 580 MHz.

  Therefore, by including the sub-element 1132, the antenna device 1 can shift the operating band of the radiating element 11, that is, the operating band on the low frequency side, to the low frequency side. Therefore, the antenna device 1 can expand the operating band on the low frequency side to the low frequency side.

  In addition, as described above, the antenna 10 is wound around the support 30 in a state where the sub-element 1132 and the region 123 of the radiating element 12 are overlapped with each other. Thus, the length of the sub element 1132 in the longitudinal direction can be shortened. Therefore, the antenna device 1 is more compact than an antenna device provided with an antenna such as the antenna 10 deployed.

  Thus, the antenna device 1 can expand the operating band on the low frequency side without increasing the size.

(Effects of opening 1137 and opening 1138)
In order to consider the variation of the resonance frequency of the sub-element 1132, a path from the power supply region Rf to the tip of the sub-element 1132 (side connecting the point P4 and the point P10 shown in FIG. 2) is considered. A large amount of current supplied to the radiating element 11 from the connection point Pc flows in the vicinity of the contour of the radiating element 11. Therefore, here, a path passing through the vicinity of the contour of the radiating element 11 is assumed as a path through which a current flows.

  When the radiating element 11 is not provided with the opening 1137 and the opening 1138, the tip of the sub-element 1132 (the point P4 and the point P10 shown in FIG. The path to the side) is only the path (referred to as path A) that reaches the point P4 via the points P1, P2, and P3.

  On the other hand, by providing the opening 1137 in the radiating element 11, in addition to the path A, a path (path) that reaches the point P10 via the points P1, P5, P6, P7, P8, and P9. B) and a route (referred to as route C) from point P1, point P7, point P8, and point P9 to point P10 are newly generated.

  As a result, the resonance frequency of the sub-element 1132 is newly increased by two. This newly increased resonance frequency can be adjusted by the size, shape, and position of the opening 1137. Therefore, by providing the opening 1137, it becomes easy to optimize (for example, flatten) the radiation characteristic on the low frequency side.

  The opening 1138 has an effect similar to that of the opening 1137. That is, by providing the opening 1138 in the radiating element 11, in addition to the paths A to C, the point P1, the point P5, the point P6, P11, the point P12, the point P13, the point P14, the point P15, the point P8, A route from point P9 to point P10 (referred to as route D) and a route from point P1, point P5, point P6, point P11, point P14, point P15, point P8, point P9 to point P10 (route E) And a new one occurs. Thereby, since the resonance frequency of the sub-element 1132 is newly increased by two, the degree of freedom when optimizing (for example, flattening) the radiation characteristic on the low frequency side can be increased.

(Effect of sub-element 1134)
Even if the resonance frequency of the sub-element 1134 changes from the state in which the antenna 10 is deployed to the state in which the antenna 10 is wound around the support 30, the resonance frequency remains unchanged at the fourth resonance frequency. This is because the antenna device 1 is configured so that the sub-element 1134 does not overlap the region 123 ((b) of FIG. 1).

  Therefore, by adjusting the sub-element 1132 (that is, adjusting the fourth resonance frequency), it is possible to reinforce a frequency band having low radiation characteristics in the low-frequency side operation band. Therefore, the antenna device 1 can easily perform adjustment for flattening the operating band on the low frequency side.

[Example of mounting on automobiles]
An example of mounting the antenna device 1 in an automobile will be described with reference to FIG. FIG. 3A is a perspective view of the vehicle body 201 on which the vehicle-mounted antenna device including the antenna device 1 is mounted. FIG. 3B is an enlarged plan view of the vehicle body 201 shown in FIG. In addition, illustration of the coaxial cable 20 is abbreviate | omitted in (b) of FIG.

  The vehicle body 201 is a hatchback type vehicle body. In the vehicle body 201, an outer plate (body panel) including the roof 220 is configured by a metal member such as a steel plate and an aluminum plate, and a surface formed by the roof 220 is substantially horizontal. That is, the roof 220 is formed along a horizontal plane and intersects the vertical direction of the vehicle body 201. Here, the direction along the roof 220 is synonymous with the direction along the horizontal plane (xy plane in the illustrated coordinate system), and the direction crossing the roof 220 is synonymous with the direction crossing the horizontal plane.

  As shown in FIG. 3, the antenna device 1 is accommodated in a spoiler 216 functioning as a housing and mounted on the rear end of the roof 220. Therefore, the antenna device 1 constitutes the vehicle-mounted antenna device 210 together with the spoiler 216.

  The hatch gate 221 of the vehicle body 201 includes a hatch gate panel 221a that forms the lower part, a frame 221c that forms the upper part, and a rear glass 221b. The frame body 221c is composed of a pair of vertical columns and a pair of horizontal columns, and a rear glass 221b is provided in the frame. Of the pair of horizontal columns of the frame 221c, the horizontal column close to the roof 220 (upper side) is attached to the rear end of the roof 220 by a hinge (not shown). The hatch gate panel 221a and the frame 221c are made of a metal member.

  A spoiler fixing portion 221d is provided on a part of the upper horizontal column of the pair of horizontal columns of the frame 221c. A part of the horizontal column on the upper side of the frame 221c is pushed rearward, and the protruding part is used as the spoiler fixing part 221d. The spoiler fixing | fixed part 221d is comprised with the metal member similarly to the frame 221c. The surface to which the spoiler 216 of the spoiler fixing portion 221d is attached is substantially facing the zenith direction and is along the horizontal plane, like the surface formed by the roof 220. Therefore, the spoiler fixing part 221d forms the rear end part of the roof 220. In this embodiment, the spoiler fixing portion 221d is a metal member formed integrally with the frame body 221c, but is a metal member formed separately from the frame body 221c and fixed to the frame body 221c with bolts or the like. May be.

  A spoiler 216 is attached to the spoiler fixing portion 221d by fixing means (such as a bolt) not shown. By fixing to the spoiler fixing portion 221d, the upper surface of the spoiler 216 and the upper surface of the roof 220 are arranged substantially flush with each other. The spoiler 216 functions as a casing of the vehicle-mounted antenna device 210 in addition to functions such as improving the aesthetics of the vehicle body 201 and improving the aerodynamic characteristics of the vehicle body 201. The spoiler 216 incorporates the antenna device 1 and a stop lamp 219. The spoiler 216 is made of a dielectric (for example, resin) and transmits electromagnetic waves.

  The antenna device 1 is disposed at a position where it does not interfere with the stop lamp 219 inside the spoiler 216. Specifically, the antenna device 1 is arranged to be shifted to the left side of the stop lamp 219 while avoiding the stop lamp 219 arranged at the center of the spoiler 216 in the left-right direction.

  As described above, when the antenna device 1 is accommodated in the spoiler 216 and the spoiler 216 is mounted on the rear end of the roof 220, the coaxial cable 20 of the antenna device 1 includes the opening provided in the spoiler 216, and the hatch gate 221. It is drawn into the interior of the vehicle body 201 through an opening provided in the upper part (for example, spoiler fixing part 221d).

  In this mounting example, the antenna device 1 is accommodated in the spoiler 216 in the state shown in FIG. That is, the antenna device 1 is accommodated in the spoiler 216 with the wall 31 of the support 30 facing the zenith and the wall 33 facing the ground.

  This mounting example shows an example when the antenna device 1 is mounted on the vehicle body 201. When the antenna device 1 is mounted on the vehicle body 201, the position and the orientation of the antenna device 1 in the spoiler 216 are arbitrary.

〔Example〕
The antenna device 1 according to the embodiment of the present invention was obtained by determining the size of each part of the antenna 10 as shown in FIG. 4 in the antenna device 1 shown in FIG. FIG. 4 is a development view of the antenna 10 provided in the antenna device 1 of the present embodiment.

  FIG. 5 is a graph showing the frequency dependence (hereinafter referred to as VSWR characteristic) of VSWR obtained by measurement using the antenna device 1 of the present embodiment.

  As described above, the antenna device 1 is designed on the assumption that it operates in the LTE frequency band. As an antenna device for LTE, if VSWR is 3 or less, it is considered to be sufficiently practical. Therefore, hereinafter, a frequency band in which VSWR is 3 or less is set as an operation band of the antenna device 1.

  Referring to FIG. 5, it was found that the antenna device 1 has a VSWR of 3 or less over the entire frequency band of 580 MHz to 3 GHz. Therefore, it was found that the operating band of the antenna device 1 is not less than 580 MHz and not more than 3 GHz.

  What should be noted here is that a very low lower limit frequency of 580 MHz is realized in the operating band on the low frequency side. This lower limit frequency is obtained by adopting a configuration in which the antenna 10 of the antenna device 1 includes the sub-element 1132 and the sub-element 1132 and the region 123 of the radiating element 12 overlap.

  As described above, the antenna device 1 can be suitably used as an antenna device that constitutes a part of the vehicle-mounted antenna device. When the antenna device 1 is mounted on the rear end of the roof of the vehicle body, the radiation characteristics may change depending on various conditions such as the mounting position. This change in radiation characteristics is likely to appear significantly in the operating band on the low frequency side. Specifically, the lower limit frequency of the operating band on the low frequency side is easily shifted to the high frequency side. Therefore, by realizing an operating band having a margin with respect to 698 MHz, which is the lower limit value of the low frequency side frequency band for LTE, even when mounted on various vehicle types, It is possible to prevent the lower limit frequency from exceeding 698 MHz. Therefore, even when the antenna device 1 is mounted on various vehicle types, the antenna device 1 can exhibit practical performance as an LTE antenna device.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and the embodiments can be obtained by appropriately combining technical means disclosed in different embodiments. The form is also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Antenna apparatus 10 Antenna 11 Radiation element (1st radiation element)
1132 Sub-element 12 Radiation element (second radiation element)
121 Power supply part 122 area | region (1st area | region of a 2nd radiation | emission element)
123 region (second region of the second radiating element)
20 Coaxial cable (feed cable)
30 Support 31 Wall (The surface constitutes the first surface)
32 walls (the surface constitutes the second surface)
33 walls (surface constitutes third surface)
34-36 walls

Claims (1)

A first surface, a second surface that intersects the first surface, and a third surface that is along the first surface direction and intersects the second surface and is spaced apart from the first surface. A support;
(1) a first radiating element having a first resonance frequency and disposed along the first surface; and (2) a second resonance having a frequency higher than the first resonance frequency. A first region having a frequency and disposed along the second surface; and a second radiating element including a second region disposed along the third surface. And comprising
The first radiating element includes a sub-element extended in a direction approaching the second surface,
When the first radiating element is viewed in plan, the sub-element partially or entirely overlaps the second region.
An antenna device characterized by that.

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