JP2013021418A - Antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device in which VSWR can be adjusted simply while suppressing an increase in the size.SOLUTION: The antenna device 1 includes a linear antenna element 20 having one end serving as a feeding point FP and the other open end, a ground part 10 being connected with one end of the antenna element 20, and an adjustment element 30 consisting of a sharing region 30A for sharing a region 20A from one end of the antenna element 20 to a midway position thereof, and a coupling region 30B branched from the midway position thereof and coupled capacitively with the ground part 10. Other region 20B in the antenna element 20 extends to the side opposite from the side of the coupling region 30B, with reference to a line passing through the midway position and one end of the antenna element 20.

Description

  The present invention relates to an antenna device that can easily adjust the VSWR while suppressing an increase in size.

  A planar antenna is known as an antenna device used in a small electronic device such as a cellular phone. For example, as shown in Patent Document 1, an antenna device with a pattern wiring is proposed.

  The antenna device of Patent Document 1 includes a linear first antenna element extending along the ground from a feeding point, and a linear second antenna element extending in parallel with the first antenna element from the feeding point. Have.

  When such an antenna device is provided in an electronic device, the resonance frequency and the value of VSWR (Voltage Standing Wave Ratio) may be shifted depending on the relative position with other components. In such a case, It is necessary to adjust the value for each electronic device to be installed. In general, as the simplest method for adjusting the resonance frequency and VSWR, it is known to change the shape of the antenna element by cutting it or the like.

JP 2010-278990

  However, in the antenna device of Patent Document 1, since the first antenna element and the second antenna element extend along the ground and are capacitively coupled to the ground, resonance occurs when the shape of these antenna elements is changed. Both frequency and VSWR fluctuate greatly. Therefore, skill is required to adjust the resonance frequency and VSWR.

  If an adjustment element capable of mainly adjusting VSWR can be provided, the adjustment of the resonance frequency and VSWR is considered to be simplified. However, if such an adjustment element is provided, the installation area tends to increase and the size tends to increase. is there.

  The present invention has been made in consideration of the above points, and an object of the present invention is to propose an antenna device capable of easily adjusting the VSWR while suppressing an increase in size.

  In order to solve this problem, the antenna device of the present invention includes a linear antenna element having one end as a feeding point and the other end being an open end, a ground portion connected to the one end of the antenna element, The antenna element includes a common region that shares a region from the one end to the midway position, and an adjustment element that includes a coupling region that branches from the midway position and is capacitively coupled to the ground portion. .

  According to such an antenna device, a part of the coupling region in the adjustment element is removed, so that the value of VSWR can be increased when capacitive coupling with the ground portion is reduced. On the other hand, when a conductive member is added to the coupling region and the capacitive coupling with the ground portion increases, the value of VSWR can be lowered. In these cases, the shape such as the length and width of the coupling region is changed, but the shape of the antenna element is not changed at all. Therefore, by changing the shape of the coupling region in the adjustment element, it is possible to preferentially change the VSWR while suppressing the change in the resonance frequency of the antenna element, and as a result, it is possible to easily adjust the VSWR. In addition, since the area other than the coupling area of the adjustment element is shared with the antenna element, the area other than the coupling area of the adjustment element is shared with the antenna element as compared with the case where the adjustment element is provided in another place in the antenna device. The installation area can be reduced by that amount, and as a result, the antenna device can be reduced in size. In this way, an antenna device that can easily adjust the VSWR while suppressing an increase in size is realized.

  Further, the region from the midway position to the other end of the antenna element is on the line passing through the midway position and the one end of the antenna element, or the coupling area of the adjustment element with reference to the line. It is preferable to extend on the opposite side to the side.

  According to such an antenna device, since the area other than the area shared with the adjustment element is separated from the adjustment element, the amount of capacitive coupling between the adjustment element and the antenna element is greatly reduced. be able to. Therefore, even when the shape of the coupling region is changed by an action such as cutting the coupling region or adding a conductor to the coupling region, the change in antenna characteristics other than the resonance frequency in the antenna element is caused by the change. Large fluctuations can be suppressed. As a result, the VSWR can be changed more preferentially.

  The ground portion includes a ground body serving as a reference potential, and a linear extension portion extending from the ground body and passing between the ground body and the coupling region, and the coupling region includes the extension. It is preferable to capacitively bind to the site.

  According to such an antenna device, the distance between the extension portion connected to the ground body and the coupling region can be reduced without changing the distance between the ground body and the coupling region of the adjustment element. Therefore, even if the degree of change of the coupling region, which is changed by an action such as cutting the coupling region or adding a conductor to the coupling region, is small, the VSWR can be changed more greatly, and the adjustment of the VSWR is further simplified. Become.

  Moreover, it is preferable that the said connection area | region extends along the said extension site | part.

  According to such an antenna device, the coupling amount of capacitive coupling between the coupling region and the extended portion of the ground portion becomes equal at any position in the coupling region of the adjustment element. Therefore, the VSWR can be easily adjusted as compared with the case where a difference occurs in the amount of capacitive coupling between the extension sites at different positions in the binding region.

  The coupling region and the region from the midway position to the other end of the antenna element are preferably arranged in the same straight line.

  According to such an antenna device, the height can be reduced as compared with the case where the antenna devices are not arranged in the same straight line.

  As described above, according to the present invention, an antenna device that can easily adjust the VSWR while reducing the size is provided.

It is the schematic which looked at the antenna apparatus which concerns on embodiment of this invention from right above. It is the schematic which illustrates the other form which replaces the ground part of FIG. FIG. 7 is a schematic view illustrating another form instead of the antenna element of FIG. 1. FIG. 10 is a schematic view illustrating another form replacing the adjustment element of FIG. 1.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of an antenna device according to the invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic view of an antenna device according to an embodiment of the present invention viewed from directly above. As shown in FIG. 1, the antenna device 1 includes a ground unit 10, an antenna element 20, and an adjustment element 30 as main components, and is fed through a coaxial cable 40 that is a feed line.

  The coaxial cable 40 includes an inner conductor 41, an insulating member 42 that covers the outer peripheral surface of the inner conductor 41, an outer conductor 43 that covers the outer peripheral surface of the insulating member 42, and a jacket 44 that covers the outer conductor 43. It is supposed to be configured.

  The inner conductor 41 is a core wire of the coaxial cable 40, and is, for example, a stranded wire of a plurality of conductive wires. The insulating member 42 is formed of an insulating resin, and the external conductor 43 is, for example, a metal braid in which a plurality of conductive wires are knitted. The jacket 44 is an insulating coating layer such as a thermoplastic resin.

  The ground portion 10 includes a ground body 11 serving as a reference potential, and a grounding part 12 and an extension part 13 connected to the ground body 11.

  The grounding part 12 is a part to be mounted on the outer conductor 43 of the coaxial cable 40. The grounding portion 12 in this embodiment is wired as a strip-shaped conductor pattern that protrudes in a direction orthogonal to the one end 11A from an intermediate portion between one end and the other end of the one end 11A in the ground body 11. The leading end portion of the outer conductor 43 in the coaxial cable 40 is fixed to the leading end portion of the conductor pattern by soldering or the like.

  The extension part 13 is a part that connects the feeding point FP to be connected to the inner conductor 41 of the coaxial cable 40 and the ground body 11 and has a linear shape having a predetermined width. The extension part 13 of this embodiment is wired as an inverted L-shaped conductor pattern. Specifically, the belt-shaped first region 13A extending from one end of the one side end 11A in the ground body 11 in a direction perpendicular to the one side end 11A, and from the tip of the first region 13A along the one side end 11A. And a belt-like second region 13B extending to a position before the ground contact portion 12. One end portion of the inner conductor 41 of the coaxial cable 40 is fixed to the distal end portion of the second region 13B by soldering or the like.

  The antenna element 20 is a linear conductive member having a predetermined width, one end of which is a feeding point FP and the other end is an open end. The length from one end of the antenna element 20 to the other end is set to a length corresponding to a quarter wavelength of the frequency to be resonated. The antenna element 20 of this embodiment is wired as an inverted L-shaped conductor pattern. Specifically, the belt-shaped first region 20A extending in a direction orthogonal to the one side end 11A of the ground body 11 from the feeding point FP, and the tip of the first region 20A, the first region 20A as a reference and the extension portion 13 It is composed of a band-shaped second region 20B extending along the side end 11A opposite to the side where the conductor pattern is present.

  The adjustment element 30 includes a region that shares a part of the antenna element 20 and a region that branches from a midway position of the antenna element 20. The adjustment element 30 of this embodiment is printed and wired as an L-shaped conductor pattern. Specifically, the shared region 30A sharing the first region 20A of the antenna element 20 and the side where the conductor pattern of the extension portion 13 is branched from the connecting portion of the first region 20A and the second region 20B of the antenna element 20 And a band-shaped coupling region 30B extending along the side end 11A.

  Since the second region 13B of the extension part 13 that connects between the ground body 11 and the feeding point FP is interposed between the coupling region 30B and the ground body 11, the coupling region 30B includes the extension part 13. And capacitive coupling with a predetermined coupling amount C. In FIG. 1, the portion indicated by a broken line as “C” is represented as a virtual one and is not represented as an electronic component.

  The width of the coupling region 30B in this embodiment is the same as the width of the antenna element 20, but may be different. The length of the coupling region 30B in this embodiment is different from the length of the antenna element 20, but may be the same. Furthermore, the thickness of the coupling region 30 </ b> B in this embodiment may be the same as or different from the thickness of the antenna element 20.

  Such adjustment in the antenna device 1 is performed, for example, by cutting the tip of the coupling region 30B of the adjustment element 30 or the end facing the extended portion 13 of the ground 10 or adding a conductive member to these ends. Is done.

  When the end of the coupling region 30B is scraped, the capacitive coupling amount C between the coupling region 30B and the second region 13B of the extension portion 13 decreases, so that VSWR increases. On the other hand, when a conductive member is added to the end of the coupling region 30B, the capacitive coupling amount C between the coupling region 30B and the second region 13B of the extension portion 13 increases, so that VSWR decreases. In these cases, the length, width, and the like of the coupling region 30B in the adjustment element 30 are changed, but the length of the antenna element 20 itself remains a quarter wavelength and is not changed at all. Therefore, even if the shape of the coupling region 30B is changed, a significant variation in the resonance frequency in the antenna element 20 is suppressed.

  As described above, the adjustment element 30 can preferentially change the VSWR while suppressing the fluctuation of the resonance frequency of the antenna element 20.

  As described above, the adjustment element 30 in the antenna device 1 of the present embodiment shares the first region 20A from one end of the antenna element 20 to the midway position, branches from the midway position, and extends from the ground portion 10. 13 is capacitively coupled. Therefore, the amount of capacitive coupling with the coupling region 30B can be changed by cutting the coupling region 30B of the adjustment element 30 or adding a conductive member without changing the length of the antenna element 20 itself. Therefore, it is possible to preferentially change the VSWR while suppressing the change of the resonance frequency of the antenna element 20, and as a result, it is possible to easily adjust the VSWR.

  In addition, the shared region 30A, which is a region other than the coupling region 30B of the adjustment element 30, is shared as the first region 20A of the antenna element 20, and therefore, compared with the case where the adjustment element 30 is provided in another place in the antenna device 1. Thus, the installation area can be reduced by the shared area 30A. As a result, the antenna device 1 can be reduced in size.

  Further, in the antenna element 20, the second region 20B other than the first region 20A shared with the adjustment element 30 is opposite to the side where the coupling region 30B of the adjustment element 30 is present with reference to a line passing through the first region 20A. Extends to the side. Therefore, compared to the case where the second region 20B of the antenna element 20 extends on the side where the coupling region 30B is present, the second region 20B of the antenna element 20 is separated from the coupling region 30B, and the second region 20B and the coupling region are separated. The amount of capacitive coupling with 30B is greatly reduced. Therefore, even when the shape of the coupling region 30B is changed by an action such as cutting the coupling region 30B or adding a conductor to the coupling region 30B, an antenna other than the resonance frequency in the antenna element 20 is accompanied by the change. It can suppress that the fluctuation | variation of a characteristic fluctuates significantly. As a result, the VSWR can be changed more preferentially.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the outer conductor 43 of the coaxial cable 40 is fixed to the grounding portion 12. However, the surface portion other than the tip of the coaxial cable 40 may be cut out to expose the external conductor 43 from the jacket 44, and the exposed portion may be fixed to the ground body 11. When fixed in this manner, the ground contact portion 12 can be omitted, and the antenna device 1 can be downsized accordingly. However, the above-described embodiment is preferable from the viewpoint of ensuring straightness of the coaxial cable 40.

  Further, in the above embodiment, the inverted L-shaped extension portion 13 is arranged from one end of the one side end 11A of the ground body 11, but one end of the one side end 11A of the ground body 11 and the feeding point FP in the antenna element 20 are arranged. If it is the extension part which connects the end of the side, the shape and arrangement | positioning aspect of various extension parts are applicable. For example, as shown in FIG. 2A, one end of one side end 11A of the ground body 11 and one end of the antenna element 20 on the feeding point FP side are connected in a state orthogonal to the one end 11A of the ground body 11. The extension part 53 may be arrange | positioned. As another example, as shown in FIG. 2B, one end of the one side end 11 </ b> A of the ground body 11 and the feeding point FP side of the antenna element 20 in a state inclined to the one side end 11 </ b> A of the ground body 11. An extension portion 63 that connects one end of each of them may be arranged.

  When the extension part 53 shown in FIG. 2A is applied, the area corresponding to the second area 13B of the extension part 13 in the above embodiment can be omitted, so that the antenna device 1 can be downsized accordingly. On the other hand, when an extension part that passes between the coupling region 30B of the adjustment element 30 and the ground body 11 is applied, such as the extension part 13 of the above embodiment or the extension part 63 shown in FIG. Even if the distance between 30B and the ground body 11 is not changed, the amount of capacitive coupling with the coupling region 30B increases. Therefore, even if the degree of change of the coupling region, which is changed by an action such as cutting the coupling region 30B or adding a conductor to the coupling region 30B, is small, the VSWR can be changed more greatly, and the VSWR can be further adjusted. It becomes simple.

  When the coupling region 30B of the adjustment element 30 extends along the extended portion passing between the adjustment element 30 and the ground body 11, the extension region 13 can be located at any position in the coupling region 30B. The amount C of capacitive coupling with the second region 13B becomes equal. Therefore, the VSWR can be easily finely adjusted as compared with the case where the coupling amount of the capacitive coupling between the adjustment region 30 and the second region 13B of the extension portion 13 differs at different positions of the coupling region 30B. it can.

  In the above embodiment, the inverted L-shaped antenna element 20 is applied, but various shapes of antenna elements can be applied. For example, as shown in FIG. 3, a strip-shaped antenna element 70 extending from one end to the other end in a direction perpendicular to the one side end 11A of the ground body 11 is applicable. However, from the viewpoint of reducing the height, the adjustment element 30 is based on a line passing through one end of the antenna element 20 on the feeding point FP side and the connecting portion between the antenna element 20 and the adjustment element 30 as in the above embodiment. It is preferable that the antenna element 20 is on the opposite side of the certain side.

  Moreover, in the said embodiment, although the L-shaped adjustment element 30 was applied, the adjustment element of various shapes is applicable. For example, as shown in FIG. 4, the coupling region 30B of the adjustment element 30 is a first adjustment part AR1 extending along the extension part 13, and a first protrusion protruding toward the extension part 13 from the first adjustment part AR1. It may consist of two adjustment sites AR2. In this case, the capacitive coupling between the second adjustment site AR2 and the extension site 13 is larger than the capacitive coupling between the first regulation site AR1 and the extension site 13. For this reason, compared with the case where the open end of 1st adjustment site | part AR1 is shaved, the raise width of VSWR becomes large when the open end of 2nd adjustment site | part AR2 is shaved by the same amount as the amount of cutting. Therefore, the VSWR can be roughly adjusted using the second adjustment part AR2, and the VSWR can be finely adjusted using the first adjustment part AR1.

  The present invention is applicable to communication terminals such as mobile phones, PDAs (Personal Digital Assistants), and game machines.

DESCRIPTION OF SYMBOLS 1 ... Antenna apparatus 10 ... Ground part 11 ... Ground main body 11A ... One side surface 12 ... Grounding site | part 13,53,63 ... Extension site | part 13A ... 1st area | region 13B ... -2nd area | region 20,70 ... Antenna element 20A ... 1st area | region 20B ... 2nd area | region 30 ... Adjustment element 30A ... Shared area | region 30B ... Coupling area | region 40 ... Coaxial cable 41 ... Inner conductor 42 ... Insulating member 43 ... Outer conductor 44 ... Jacket AR1 ... First adjustment part AR2 ... Second adjustment part C ... Coupling amount FP ... Power supply point

Claims (5)

A linear antenna element having one end as a feeding point and the other end as an open end;
A ground portion connected to the one end of the antenna element;
An antenna device comprising: a shared region that shares a region from the one end to a midway position in the antenna element; and an adjustment element that includes a coupling region that branches from the midway position and is capacitively coupled to the ground portion. . The region from the midway position to the other end of the antenna element is
2. The line extending through the halfway position and the one end of the antenna element, or on the side opposite to the side where the coupling region of the adjusting element is located with respect to the line. The antenna device described. The ground part has a ground body serving as a reference potential, and a linear extension portion extending from the ground body and passing between the ground body and the coupling region,
The antenna device according to claim 1, wherein the coupling region is capacitively coupled to the extension part. The antenna device according to claim 3, wherein the coupling region extends along the extension part. 5. The antenna device according to claim 1, wherein the coupling region and a region from the midway position to the other end of the antenna element are arranged in a straight line.

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