JP2008131477A - Antenna unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna unit capable of improving radiation efficiency without damaging multiple frequency sharing characteristics and broadband characteristics. <P>SOLUTION: A power supply conductor pattern 110 has a folded part 111 and a power supply terminal 112 on one end. Also, a grounding conductor pattern 120 is also formed in a shape roughly the same as the power supply conductor pattern 110, has a folded part 121 and a grounding terminal 122 on one end. An extension element 130 is disposed on the opposite side of a base plate 140 with respect to a base part 101, and one end of it is connected to the folded part 121 of the grounding conductor pattern 120. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a small antenna device suitable for being incorporated in a portable terminal or the like, and particularly to an antenna device having excellent radiation characteristics.

  2. Description of the Related Art Conventionally, with the spread of terminal devices such as mobile phones and the advancement of their functions, technological developments such as downsizing and widening of the antenna device built in the terminal devices have been promoted. As an example of such an antenna device, for example, one described in Patent Document 1 is known. In the antenna described in Patent Document 1, a linear conductor corresponding to a quarter wavelength is bent and fixed on a dielectric, and is built in a portion without a circuit board in a mobile phone casing. . Simple structure and high degree of freedom in antenna shape.

  In addition, a built-in antenna with improved functions such as impedance matching and broadband has been proposed (Patent Documents 2 and 3). In Patent Document 2, a multi-frequency shared characteristic and a broadband characteristic are realized by a method of forming a feeding pattern and a ground pattern with a folded monopole antenna having a folded portion, adjusting the arrangement thereof, and providing a short-circuit portion. Further, in Patent Document 3, a structure in which a parallel two-wire antenna having complicated electromagnetic coupling is included in a dielectric is used to achieve both miniaturization and multi-frequency shared characteristics and broadband characteristics.

  In these antennas, a monopole antenna is composed of a single conductor, but by adjusting the electromagnetic coupling between two lines composed of two parallel linear conductors, Multi-frequency shared characteristics and broadband characteristics are realized by using superposition of in-phase mode / reverse-phase mode among the flowing currents.

Furthermore, a technique for improving radiation characteristics by combining with a conductor pattern configured on a substrate on which a small chip antenna is mounted is also known (Patent Document 4). In Patent Document 4, an effective resonance length is increased by connecting a chip antenna in series with a printed pattern on a circuit board.
JP 2004-215149 A Japanese Patent Laid-Open No. 2005-203878 JP 2005-303637 A Japanese Patent Laid-Open No. 11-330830

  However, the conventional antenna has the following problems. The monopole antenna described in Patent Document 1 has a simple structure, but has a narrow impedance adjustment range, and it is extremely difficult to avoid a decrease in impedance due to the influence of the surroundings. For this reason, the antenna characteristics strongly depend on the distance to the end of the ground plane or other electronic components, and there is a problem that only low-bandwidth and low-efficiency characteristics can be obtained when the distance cannot be secured sufficiently.

  In addition, the monopole antenna can have multi-frequency shared characteristics by introducing a folded structure. However, in this case as well, since the frequency ratio (ratio of higher-order mode to basic mode) is strongly influenced by the surroundings, in order to use as a multi-frequency antenna, it is necessary to design the shape of the antenna element for each housing, There is a problem that it becomes a completely custom design in which a multi-frequency shared characteristic is created for each portable terminal, and development takes a long time.

  In the antennas described in Patent Documents 2 and 3, various characteristics can be improved as compared to a monopole antenna (high impedance, wide band due to double resonance, etc.). On the other hand, two conductors are wired substantially in parallel and between the lines. Since it is necessary to consider electromagnetic coupling, the design becomes complicated and it becomes difficult to achieve compatibility with the shape freedom of the antenna. In addition, when trying to have multi-frequency shared characteristics, the design becomes more complicated.

  In the antenna described in Patent Document 4 in which the conductor pattern on the printed circuit board is connected in series to the small antenna, the resonance frequency of the antenna is directly influenced by the conductor pattern on the printed circuit board. When the chip antenna has multi-frequency shared characteristics (not described in the publicly known example), the frequency ratio between the multiple frequencies is also greatly influenced by the length of the conductor pattern. As a result that the multi-frequency shared characteristics are disturbed by the conductor pattern on the printed circuit board, the effect of improving the radiation efficiency in the used frequency band cannot be obtained.

  Accordingly, the present invention has been made to solve the above problem, and an object of the present invention is to provide an antenna device capable of improving the radiation efficiency without impairing the multi-frequency shared characteristic and the broadband characteristic.

  According to a first aspect of the antenna device of the present invention, a power supply conductor pattern having at least one folded portion, and a grounding conductor pattern having at least one folded portion and having substantially the same shape as the power supply conductor pattern are provided. A base portion arranged in parallel and arranged near or above the ground plane, and an extension line disposed on the opposite side of the base portion from the ground plane and having one end connected to a predetermined position of the grounding conductor pattern And a conductor element.

  Another aspect of the antenna device of the present invention is characterized in that the one end of the extended linear conductor element is connected to a folded portion of the grounding conductor pattern.

  In another aspect of the antenna device of the present invention, a distance (electric length) between the extended linear conductor element and the base portion is a distance (electric length) between the feeding conductor pattern and the ground pattern in the base portion. ), The distance between the folded conductor patterns for feeding (electric length) and the distance between the folded conductor patterns for grounding (electric length).

  Another aspect of the antenna device of the present invention is characterized in that an electrical length of the extended linear conductor element is 1/20 wavelength or more at the lowest frequency used.

  In another aspect of the antenna apparatus of the present invention, the base portion includes an inner dielectric layer sandwiched between the power supply conductor pattern and the grounding conductor pattern, the power supply conductor pattern, and the grounding conductor pattern. And an outer layer dielectric that encloses the substrate.

  According to another aspect of the antenna device of the present invention, a central portion of the base portion is enclosed by the outer layer dielectric, and a feeding terminal formed in the feeding conductor pattern and a ground terminal formed in the grounding conductor pattern are provided. One end portion of the base portion provided, and the other end portion of the base portion including the folded portion of each of the feeding conductor pattern and the grounding conductor pattern, together with the inner dielectric layer, the outer dielectric layer And the one end of the extended linear conductor element is connected to the portion of the grounding conductor pattern exposed from the outer dielectric of the base portion.

  In another aspect of the antenna device of the present invention, the feeding conductor pattern and a part of the grounding conductor pattern together with the inner-layer dielectric are further provided in a central portion of the base portion and from a side surface opposite to the ground plane. It is exposed, and the extended linear conductor element is disposed on the exposed inner layer dielectric.

  Another aspect of the antenna device according to the present invention is characterized in that the extended linear conductor element is disposed along a wall surface on the opposite side of the ground plate of the support base for fixing the base portion.

  Another aspect of the antenna device of the present invention is characterized in that the extended linear conductor element is formed as a conductor pattern on an inner wall surface on the opposite side of the ground plate of the casing that houses the base portion. To do.

  According to the present invention, an extended linear conductor element is connected to a base portion composed of a parallel two-wire antenna having a folded portion, so that multiple frequencies can be shared by complex electromagnetic field coupling between four conductors adjacent to each other at the base portion. It is possible to realize a characteristic and a broadband characteristic, and to improve the radiation characteristic with the extended linear conductor element without impairing the characteristic. Since the extended linear conductor element can arbitrarily arrange the space inside the housing that houses the base, it is possible to improve the radiation characteristics by making maximum use of the empty space inside the housing. Become.

  An antenna device according to a preferred embodiment of the present invention will be described in detail with reference to the drawings. In addition, about each structural part which has the same function, the same code | symbol is attached | subjected and shown for simplification of illustration and description.

  An antenna device according to a first embodiment of the present invention will be described with reference to the perspective view shown in FIG. The antenna device 100 according to the present embodiment includes a base portion 101 including a feeding conductor pattern 110 and a grounding conductor pattern 120, an extension element 130 that is a linear conductor, and a ground plane 140. The ground plane 140 may be another circuit board housed in the housing 11. FIG. 1 shows a state in which the antenna device 100 is built in one end of the casing 11 of the mobile terminal.

  The power supply conductor pattern 110 has a folded portion 111 and is provided with a power supply terminal 112 at one end. The grounding conductor pattern 120 is also formed in substantially the same shape as the power feeding conductor pattern 110, and has a folded portion 121 and a ground terminal 122 at one end. Two conductor patterns of a power supply conductor pattern 110 and a ground conductor pattern 120 are arranged substantially in parallel to constitute the base portion 101. In the base portion 101, the four lines of the folded feeding conductor pattern and grounding conductor pattern are close to each other, and electromagnetic coupling is formed between the lines. As a result, multi-frequency shared characteristics and broadband characteristics can be obtained. In the present embodiment, the base portion 101 is disposed close to one side of the ground plane 140, but may be disposed above the ground plane 140.

  The antenna device 100 according to the present embodiment includes an extension element 130 that is a linear conductor having one end connected to the base portion 101, and the extension element 130 is opposite to the base plate 140 with respect to the base portion 101. To be placed in. The extension element 130 is connected to the grounding conductor pattern 120 of the base portion 101 and is disposed substantially parallel to the power supply conductor pattern 110 and the grounding conductor pattern 120.

  A detailed structure of the antenna device 100 is shown in FIG. FIG. 2 shows a top view, a bottom view, and a cross-sectional view of the antenna device 100. 2A is a partial top view of the antenna device 100, FIG. 2B is a partial bottom view thereof, FIG. 2C is a cross-sectional view taken along line AA ′ shown in FIG. ) A sectional view taken along line BB ′ shown in the top view is shown. As shown in FIGS. 2A and 2B, the power supply conductor pattern 110 and the grounding conductor pattern 120 are both formed in substantially the same shape having folded portions 111 and 121. Further, the expansion element 130 is disposed along the inner wall of the housing 11 on the side opposite to the ground plane 140.

The expansion element 130 can be connected in the middle of the grounding conductor pattern 120, but is preferably connected to the folded portion 121. In the antenna device 100 of the present embodiment, the extension element 130 is connected to the folded portion 121 of the grounding conductor pattern 120. Furthermore, the distance (electric length) between the expansion element 130 and the base portion 101 should be larger than the distance (electric length) between the power supply conductor pattern 110 and the ground conductor pattern 120 in the base portion 101. .

  2A and 2B, the distance L between the folded conductors in each of the feeding conductor pattern 110 and the grounding conductor pattern 120 and the base portion 101 (the feeding conductor pattern 110 and the grounding conductor pattern 120 are shown. ) And the expansion element 130 is described. 2C and 2D, the distance N between the power supply conductor pattern 110 and the ground conductor pattern 120 is shown. In the distances L, M, and N between these conductors, the extension element 130 is preferably arranged so that the distance M between the conductors 110 and 120 is greater than the distances L and N between the conductors 110 and 120. By disposing the expansion element 130 in this way, it is possible to greatly improve the radiation characteristics of the expansion element 130 without degrading the multi-frequency shared characteristic and the wideband characteristic realized by the base unit 101.

  In the antenna device 100 of the present embodiment, the feeding conductor pattern 110 and the grounding conductor pattern 120 that form the base portion 101 are formed as parallel two-wire antennas having the folded portions 111 and 112, respectively. These conductors are close to each other to form a complicated electromagnetic coupling. Conventionally, the base unit 101 has adjusted the electromagnetic field coupling by optimizing the distance, dielectric constant, line width, and facing area of the four conductors in order to realize desired multi-frequency shared characteristics and broadband characteristics. Therefore, there is a restriction that the shapes of the power supply conductor pattern 110 and the ground conductor pattern 120 cannot be freely changed.

  For this reason, even if there is a vacant space inside the housing, it has been impossible to change the shape of the base portion 101 so that the radiation efficiency can be increased by using the space to the maximum extent. Therefore, in the antenna device 100 according to the present embodiment, the expansion element 130 is added without changing the shape of the base portion 101, so that the space inside the housing 11 can be effectively utilized.

  In the antenna device 100, the extension element 130 is disposed on the opposite side of the base plate 140 with respect to the base portion 101, and the distance (electrical length) from the base portion 101 is set to the power supply conductor pattern 110 in the base portion 101 and grounding. By arranging it so as to be larger than the distance (electric length) between the conductor pattern 120, the multi-frequency shared characteristic and the broadband characteristic realized by the base unit 101 are prevented from being affected as much as possible. Further, by connecting the expansion element 130 to the folded portion 121 of the grounding conductor pattern 120, the influence on the multi-frequency shared characteristic and the wideband characteristic of the base part 101 can be further reduced.

  On the other hand, in terms of radiation characteristics, by arranging the expansion element 130 by making the most effective use of the space inside the housing, the radiation efficiency is improved according to the size of the space acquired by the expansion element 130. It becomes possible. The length of the extension element 130 is preferably as long as possible, and the electrical length may be 1/20 or more of the wavelength corresponding to the lowest use frequency among the multi-frequency shared characteristics, and as much as possible in the available space. It is more preferable to arrange widely. Note that the length of the expansion element is independent of the resonance frequency.

  As described above, according to the antenna device 100 of the present embodiment, desired base multi-frequency characteristics and wideband characteristics are realized by the base unit 101, and a vacant space or shape of the casing 11 in which the antenna device 100 is built. Accordingly, the radiation characteristics can be enhanced by disposing the expansion element 130 in as wide a space as possible without degrading the multi-frequency shared characteristics and the broadband characteristics of the base portion 101.

  In the antenna device 100 of this embodiment, the power supply conductor pattern 110 and the grounding conductor pattern 120 are arranged in parallel to form the base portion 101. The conductor patterns 110 and 120 are included in a dielectric. The base unit 101 may be used. That is, the base portion 101 can be formed by sandwiching a predetermined dielectric between the power supply conductor pattern 110 and the ground conductor pattern 120 and covering it with another dielectric. By including the conductor patterns 110 and 120 in the dielectric as described above, the base portion 101 can be reduced in size. Note that one end where the folded portions 111 and 121 of the power supply conductor pattern 110 and the grounding conductor pattern 120 are formed and both ends of the other end including the power supply terminal 112 and the ground terminal 122 are not covered with a dielectric. You may make it expose.

  In the present embodiment, the power supply conductor pattern 110 and the grounding conductor pattern 120 constituting the base portion 101 each have one folded portion 111 and 121, but it is sufficient that there is at least one folded portion. Two or more plural pieces may be formed.

  An antenna device according to a second embodiment of the present invention will be described with reference to FIG. In the figure, (a) is a perspective view of a portable terminal in which an antenna device 200 is built in one end of a casing 21, and (b) is an enlarged view of the antenna device 200 and a support base 22 that fixes the antenna device 200. It is a perspective view shown. 2C is a top view of the antenna device 200 and the support base 22, FIG. 4D is a left side view corresponding to the top view of FIG. 2C, and FIG. 3E is an upper side surface corresponding to the top view of FIG. FIG.

  In the antenna device 200 of this embodiment, as shown in FIGS. 3A and 3B, the feeding conductor pattern 210 and the grounding conductor pattern 220 are perpendicular to the ground plane 240 on the surface of the support base 22. The power supply conductor pattern 210 is disposed on the ground plane 240 side, and the grounding conductor pattern 220 is disposed on the wall surface side of the housing 21. Further, the respective conductor patterns 210 and 220 are formed such that the distance between the opposing conductors of each conductor pattern folded by the folded portions 211 and 221 is shortened by bending the central portions 210a and 220a into a substantially concave shape. Yes.

  Further, as shown in FIG. 3C, the central portions 210a and 220a are parallel to the ground plane 240 so that the distance between the central portion 210a of the power supply conductor pattern 210 and the central portion 220a of the grounding conductor pattern 220 is shortened. It is formed in a shape protruding in a substantially convex shape in any direction. In each of the central portions 210a and 220a of the conductor patterns 210 and 220 formed as described above, a part of the distance between the four adjacent conductor patterns is shortened to adjust the degree of electromagnetic field coupling, and a desired multiple Realizes both frequency sharing characteristics and broadband characteristics.

  The expansion element 230 can increase the radiation efficiency as the area surrounded by the ground plane 240 can be increased. However, the shape of the expansion element 230 when arranged in the housing 21 is not particularly limited. Therefore, in this embodiment, the expansion element 230 is arranged along the peripheral wall of the support base 22. The peripheral wall of the support base 22 of the present embodiment has a complicated shape having a curved portion as shown in FIG. 3C, but the influence of the shape of the expansion element 230 on the input impedance is slight. Its shape can be changed freely. For this reason, even if the expansion element 230 is arranged in such a complicated shape, the radiation efficiency can be increased. Further, by disposing the expansion element 230 along the peripheral wall of the support base 22, it is possible to maximize the area surrounded by the ground plane 240, thereby maximizing the radiation efficiency.

  As described above, in the antenna device of the present invention, since the expansion element can be arranged in accordance with the shape of the housing or the support base, for example, the expansion element is stored in a small space around the inner wall of the housing. It becomes possible to do.

  An antenna device according to a third embodiment of the present invention will be described with reference to FIG. In the same figure, (a) is a top view of the antenna device 300, and (b) is a back view of the antenna device 300. The base portion 301 of the antenna device 300 has a structure in which an inner layer dielectric 351 is sandwiched between a power supply conductor pattern 310 and a ground conductor pattern 320 and is further enclosed by an outer layer dielectric 352. In this embodiment, a low dielectric constant dielectric (relative dielectric constant 4) is used for the inner dielectric 351, and a high dielectric constant (relative dielectric constant 18) is used for the outer dielectric 352.

  The inner dielectric layer 351 extends and extends beyond the base portion 301, and the extending portions 313 and 323 of the power supply conductor pattern 310 and the grounding conductor pattern 320 that extend from one side of the base portion 301 to the outside are provided. The folded portions 311 and 321 are formed by a part thereof. In addition, the extending portions 314 and 324 of the power supply conductor pattern 310 and the grounding conductor pattern 320 that are extended outward from the other of the base portion 301 are connected to the power supply terminal 312 and the ground terminal 322, respectively.

  In this embodiment, the expansion element 330 is disposed on the inner layer dielectric 351 and connected to the folded portion 321 of the grounding conductor pattern 320. Thus, in this embodiment, since the expansion element 330 can be disposed on the inner layer dielectric 351, the base portion 301 and the expansion element 330 can be integrally formed. Further, by integrating the extension element 330 with the base portion 301 without making it a separate part, a support base for arranging the extension element 330 becomes unnecessary, and the work of attaching the antenna device 300 to the housing 31 is greatly simplified. Therefore, it is possible to provide a highly reliable antenna device 300 with reduced cost.

  An antenna device according to a fourth embodiment of the present invention will be described with reference to FIG. In the same figure, (a) is a perspective view of the portable terminal 40 incorporating the antenna device 400, (b) is a plan view of the portable terminal 40, and (c) is a plan view of the antenna device 400. . The antenna device 400 is a small parallel two-wire antenna similar to the above-described embodiments, and has a structure in which a feeding conductor pattern 410 and a grounding conductor pattern 420 are included in a dielectric 450.

  In the antenna device 400 of the present embodiment, the extension element 430 is formed as a conductor pattern applied on the inner wall of the housing 41. In the present embodiment, in order to prevent electromagnetic waves generated in the mobile terminal 40 from leaking to the outside or being affected by the electromagnetic waves from the outside, and to achieve electromagnetic separation between the components, Although the EMI shield pattern portion 460 is applied, the expansion element 430 can be formed simultaneously with the formation of the EMI shield pattern portion 460. In the present embodiment, the expansion element 430 can be easily formed in this manner, and a support base for disposing the expansion element 430 inside the housing 41, labor for disposing work, and the like are not required.

  The expansion element 430 formed on the inner wall of the housing 41 is configured to be connected to the folded portion 421 of the grounding conductor pattern 420 when the base portion 401 is installed inside the housing 41.

  Next, the effect of improving the radiation efficiency by providing the expansion element 430 will be described with reference to FIGS. 6 and 7 by taking the antenna device 400 of the present embodiment as an example. FIG. 6 is a graph showing changes in radiation efficiency with respect to frequency, and FIG. 7 is a graph showing changes in VSWR with respect to frequency. 6 and 7, the comparison between the case where the expansion element 430 is provided and the case where the expansion element 430 is not provided is performed using the simulation result. Here, the distance between the power supply conductor pattern 410 and the grounding conductor pattern 420 is 1.5 mm, and the interval between the folded power supply conductor pattern 410 and the grounding conductor pattern 420 is 1.4 mm. The expansion element 430 has a length of 28 mm, which is 0.084 times (1/20 times or more) 0.084 times the wavelength (333 mm) corresponding to the lowest use frequency of about 0.9 GHz in FIGS. The conductor pattern is 0.8 mm, and is arranged 5 mm away from the base portion.

  From FIG. 6, it can be confirmed that the radiation efficiency 511 when the expansion element 430 is provided is improved over the entire frequency band compared with the radiation efficiency 512 when the expansion element 430 is not provided. For example, in the low frequency band, the radiation efficiency is improved by nearly 20%. Further, it can be confirmed that the frequency at which the radiation efficiency reaches a peak does not change greatly by providing the expansion element 430.

  In FIG. 7, since there is no significant difference between the VSWR 521 when the expansion element 430 is provided and the VSWR 522 when the expansion element 430 is not provided, the influence on the input impedance of the base portion 401 due to the addition of the expansion element 430 is not observed. Can be confirmed to be small. In particular, the influence on the resonance frequency and the broadband characteristic is small, and it can be confirmed that the multi-frequency shared characteristic and the broadband characteristic realized by the parallel two lines of the base portion 401 are maintained.

  7 also shows the VSWR 523 when the expansion element 430 is connected to the folded portion 411 of the power supply conductor pattern 410. In this case, the influence on the input impedance is increased, and the resonance frequency and the broadband characteristics are increased. Can be confirmed to change significantly.

  As shown in the simulation results of FIGS. 6 and 7, in the antenna device 400 according to the present embodiment, the extension element 430 formed on the inner wall of the casing 41 is connected to the folded portion 421 of the grounding conductor pattern 420, thereby The radiation characteristics can be improved while maintaining the multi-frequency shared characteristics and the broadband characteristics realized by the two parallel lines 401.

  As described above, in the antenna device of the present invention, desired baseband characteristics and multi-frequency shared characteristics are realized by configuring the base portion with a parallel two-wire antenna having a structure capable of adjusting input impedance. In addition to this, the extension element, which is a linear conductor, is connected in the middle of the grounding conductor pattern of the parallel two-wire antenna, and the extension element is arranged at a sufficient distance from the base part. The radiation characteristics can be improved without degrading the characteristics and the multi-frequency shared characteristics.

  By disposing the expansion element along the inner wall of the casing of the mobile terminal, the electrical volume formed with the ground plane can be increased, thereby increasing the radiation efficiency of the antenna device. . Therefore, it is possible to easily obtain the maximum radiation efficiency equivalent to that of a monopole antenna having a high degree of freedom in shape and easy to secure an electric volume. Further, by adjusting the position where the extension element is connected to the base portion, the influence on the parallel two-wire antenna that is the base portion can be reduced. Therefore, according to the antenna device of the present invention, radiation efficiency can be increased while maintaining the advantages of the parallel two-wire antenna, and a high-performance antenna device can be provided.

  Note that the description in the present embodiment shows an example of the antenna device according to the present invention, and the present invention is not limited to this. The detailed configuration, detailed operation, and the like of the antenna device in this embodiment can be changed as appropriate without departing from the spirit of the present invention.

1 is a perspective view of an antenna device according to a first embodiment of the present invention. It is the top view, bottom view, and sectional drawing of the antenna device which concern on 1st Embodiment. It is the perspective view, top view, and side view of the antenna device which concern on the 2nd Embodiment of this invention. It is the upper side figure and back surface figure of the antenna device which concern on the 3rd Embodiment of this invention. It is the perspective view and top view of an antenna apparatus which concern on the 4th Embodiment of this invention. It is a graph which shows the change of the radiation efficiency with respect to a frequency. It is a graph which shows the change of VSWR with respect to a frequency.

Explanation of symbols

11, 21, 31, 41 Case 40 Mobile terminal 100, 200, 300, 400 Antenna device 101, 201, 301, 401 Base part 110, 210, 310, 410 Power supply conductor pattern 111 Folded part (feeding conductor pattern side) )
112 Power supply terminal 120, 220, 320, 420 Grounding conductor pattern 121 Folded portion (grounding conductor pattern side)
122 Grounding terminal 130, 230, 330, 430 Expansion element 140, 240, 340, 440 Ground plane

313, 314, 323, 324 Extension part 351 Inner layer dielectric 352 Outer layer dielectric 450 Dielectric 460 EMI shield pattern part 511, 512 Radiation efficiency 521, 522, 523 VSWR

Claims (9)

A power supply conductor pattern having at least one folded portion, and a grounding conductor pattern having at least one folded portion and having substantially the same shape as the power supply conductor pattern are arranged substantially parallel to each other above or near the ground plane. The arranged base part,
An extended linear conductor element disposed on the opposite side of the base plate with respect to the base portion and having one end connected to a predetermined position of the grounding conductor pattern.
An antenna device characterized by that. The antenna device according to claim 1, wherein the one end of the extended linear conductor element is connected to a folded portion of the grounding conductor pattern. The distance (electric length) between the extended linear conductor element and the base portion is the distance (electric length) between the feeding conductor pattern and the grounding pattern in the base portion, and between the folded feeding conductor patterns. The antenna device according to claim 1, wherein the antenna device is larger than a distance (electrical length) of the antenna and a distance (electrical length) between the folded grounding conductor patterns. The antenna device according to any one of claims 1 to 3, wherein an electrical length of the extended linear conductor element is 1/20 wavelength or more at a lowest frequency to be used. The base portion includes an inner dielectric layer sandwiched between the power supply conductor pattern and the ground conductor pattern;
The antenna device according to any one of claims 1 to 4, further comprising an outer layer dielectric that encloses the feeding conductor pattern and the grounding conductor pattern. A central portion of the base portion is encapsulated by the outer layer dielectric;
One end of the base portion including a power supply terminal formed on the power supply conductor pattern and a ground terminal formed on the ground conductor pattern, and each of the power supply conductor pattern and the ground conductor pattern. The other end of the base portion including the folded portion is exposed from the outer dielectric together with the inner dielectric,
The antenna device according to claim 5, wherein the one end of the extended linear conductor element is connected to a portion of the grounding conductor pattern exposed from the outer dielectric of the base portion. Furthermore, a part of the power supply conductor pattern and the grounding conductor pattern are exposed together with the inner dielectric layer from the side surface opposite to the ground plane at the center portion of the base portion,
The antenna device according to claim 5, wherein the extended linear conductor element is disposed on the exposed inner layer dielectric. The said extended linear conductor element is arrange | positioned along the wall surface on the opposite side to the said ground plate of the support stand which fixes the said base part. The any one of Claims 1-4 characterized by the above-mentioned. Antenna device. 5. The extended linear conductor element is formed as a conductor pattern on an inner wall surface of the housing that houses the base portion on the side opposite to the ground plane. 6. The antenna device according to item 1.

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