JP2017229047A - antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna that is compact and has a wider operation band than the conventional antenna.SOLUTION: An antenna (10) comprises: a first radiation element (11); and a second radiation element (12) and a third radiation element (13) that have an electric length shorter than that of the first radiation element (11), and that are arranged so as to sandwich the first radiation element (11) therebetween.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an antenna.

  In recent years, with the spread of mobile terminals such as smartphones, mobile communication (for example, automobiles) antennas for mobile communication (for example, for LTE) are mounted. Such an antenna is required to achieve both a compact size and a wide operating band.

  Patent Document 1 describes a dipole antenna that is compact and has a wide operating band. The dipole antenna described in FIG. 1 of Patent Document 1 achieves compactness and wider bandwidth than the dipole antenna that employs a non-bent radiating element by employing the bent first and second radiating elements. doing.

Japanese Patent No. 5416773 (issued on February 12, 2014)

  Although the dipole antenna described in Patent Document 1 covers a frequency band for digital terrestrial television (470 MHz to 900 MHz), its operating band is a frequency band of 698 MHz to 2690 MHz, which is an LTE frequency band. It cannot cover the bandwidth.

  The present invention has been made in view of the above problems, and is to provide an antenna having a compact size and a wider operating band than conventional antennas.

  In order to solve the above problems, an antenna according to one embodiment of the present invention includes a first radiating element, a second radiating element, and a third radiating element that have an electrical length shorter than that of the first radiating element. And a second radiating element and a third radiating element arranged so as to sandwich the first radiating element.

  The second radiating element and the third radiating element are arranged so as to sandwich the first radiating element. Therefore, this antenna is as compact as a conventional antenna.

  The electrical length of the second and third radiating elements is shorter than the electrical length of the first radiating element. That is, this antenna has a resonance point corresponding to the electrical length of the first radiating element and a resonance point corresponding to the electrical length of the second and third radiating elements. In this antenna, the electric frequency of the first radiating element and the electric lengths of the second and third radiating elements can be appropriately changed to make a desired frequency band an operating band.

  Further, in the present antenna, each of the second and third radiating elements is arranged so as to sandwich the first radiating element. According to this configuration, the value of the capacitance generated between the first radiating element and the second radiating element and the value of the capacitance generated between the first radiating element and the third radiating element can be easily obtained. Can be controlled. Therefore, it is possible to prevent the VSWR from decreasing in a specific band of the desired frequency band, and to prevent a valley of the VSWR from occurring. Therefore, this antenna can set a desired frequency band as an operation band.

  As described above, this antenna can provide an antenna that is compact in size and wider in operation band than a conventional antenna.

  In the antenna according to one aspect of the present invention, one conductor constituting the feed line is connected to one end of the first radiating element, and the other conductor constituting the feed line is connected to one end of the second radiating element. And a connector for connecting to both ends of the third radiating element.

  According to said structure, when arrange | positioning so that a 1st radiating element may be followed with respect to the extending | stretching direction of a feeder, this antenna and a feeder can be easily connected via a connector. The arrangement of the first radiating element and the second and third radiating elements 12 and 13 arranged so as to sandwich the first radiating element surrounds one conductor of the feeder line and the one conductor. This is because it coincides with the arrangement with the other conductor arranged in the.

  The antenna which concerns on 1 aspect of this invention WHEREIN: The outer edge facing the said 1st radiation element of the said 2nd radiation element WHEREIN: In the area containing the other end of the said 2nd radiation element, as the said other end approaches, the said edge A curve gradually moving away from the first radiating element is drawn, and an outer edge of the third radiating element facing the first radiating element approaches the other end in a section including the other end of the third radiating element. It is preferable to draw a curve gradually moving away from the first radiating element.

  According to the above configuration, since the second and third radiating elements 12 and 13 are configured in this manner, a VSWR valley (a sudden decrease in VSWR) that may occur in the operating band on the high frequency side of the operating band. ) Can be suppressed.

  In the antenna according to one aspect of the present invention, the outer edge of the second radiating element on the side opposite to the side facing the first radiating element is in the section including the one end of the second radiating element. A curve that gradually approaches the first radiating element as the distance from the first radiating element approaches is drawn, and the outer edge of the third radiating element opposite to the side facing the first radiating element is defined by It is preferable to draw a curve that gradually approaches the first radiating element as it approaches the one end.

  The antenna can be disposed on a conductor plate represented by an automobile roof or the like. In such a case, since the second and third radiating elements are configured as described above, the capacitance generated between the second radiating element and the conductor plate, and the third radiating element, The value of the capacitance generated between the conductor plate can be easily set as appropriate. Therefore, the VSWR is prevented from being lowered due to the arrangement on the conductor plate, and the VSWR is easily flattened in a wide operation band.

  The antenna which concerns on 1 aspect of this invention WHEREIN: A said 1st radiation | emission element is a cup type which has a head and a neck, Comprising: The edge side on the opposite side to the said head side of the said neck is said connector as said one end. Preferably, the second radiating element and the third radiating element are arranged so as to sandwich the neck of the first radiating element.

  According to said structure, each of the 2nd and 3rd radiating element which pinches | interposes a 1st radiating element can be arrange | positioned in the space formed in the both sides of the neck part of a 1st radiating element. Therefore, compared with the case where the first radiating element does not have a neck (for example, a rectangular shape), the present antenna can reduce the width of the area required for installing the antenna. That is, this antenna can be installed (accommodated) in a more compact space.

  In the antenna according to one aspect of the present invention, in a section including the one end of the first radiating element, which is longer than a width of the neck, the interval between the neck and the second radiating element, and The distance between the neck and the third radiating element is preferably constant, and the distance is determined so that the impedance of the antenna matches the characteristic impedance of the feeder line.

  According to said structure, the impedance of this antenna and the characteristic impedance (for example, 50 (ohm)) of a feeder can be matched easily. Therefore, the present antenna can suppress reflection due to impedance mismatch and obtain a high gain.

  The antenna which concerns on 1 aspect of this invention WHEREIN: It is preferable that the edge side on the opposite side to the said neck part side of the said head is not orthogonal to the central axis of the said neck part.

  According to said structure, the center axis | shaft of a neck part and the other end are not orthogonally crossed, and the length of the other end is ensured longer than the case where the center axis | shaft of a neck part and the other end are orthogonally crossed. be able to. Therefore, the present antenna 10 can improve the gain with respect to the polarization in the direction intersecting the central axis of the neck without impairing the gain with respect to the polarization in the direction along the central axis of the neck.

  An antenna according to an aspect of the present invention includes a first short-circuit portion that short-circuits one end of the first radiating element and one end of the second radiating element, the one end of the first radiating element, and the first A second short-circuit part that short-circuits the one end of the second radiating element and short-circuits the one end of the first radiating element and the one end of the third radiating element; Is preferred.

  According to said structure, the gain by the side of a low frequency can be improved compared with the case where the 1st short circuit part and the 2nd short circuit part are not provided.

  An antenna according to an aspect of the present invention includes (1) a first root portion connected to one end of the first radiating element, and (2) a second base connected to one end of the second radiating element. A root portion; (3) a third root portion connected to one end of the third radiating element; and (4) a C-shaped conductor connecting the second root portion and the third root portion. And a pattern. In the antenna, the first short-circuit portion includes the first root portion, the second root portion, and a first U-shape that connects the first root portion and the second root portion. The second short-circuit portion includes the first root portion, the second root portion, the third root portion, the C-shaped conductor pattern, and the first root portion. It is preferable that it is comprised by the 2nd U-shaped conductor pattern which connects a part and the said C-shaped conductor pattern.

  According to said structure, a 1st short circuit part and a 2nd short circuit part can be comprised, without enlarging the size of an antenna unnecessarily.

  In the antenna according to one embodiment of the present invention, the electrical length of the second radiating element and the electrical length of the third radiating element are different from each other. Of the second radiating element and the third radiating element, the radiating element having the longer electrical length includes a radiating element body including one end of the radiating element having the longer electrical length, and an end portion of the radiating element body. And the sub-radiating element extended from the end opposite to the one end of the longer radiating element to the other end of the longer radiating element. It is preferable.

  According to said structure, the 1st-3rd radiating element of this antenna has more electric length compared with the case where the radiating element with a longer electric length is not provided with the sub radiating element. Therefore, the electrical lengths of the first to third radiating elements can be determined so as to further subdivide a wide frequency band (for example, a frequency band for LTE). Therefore, this antenna can further flatten the VSWR in a wide frequency band.

  The antenna which concerns on 1 aspect of this invention WHEREIN: The outer edge facing the said 1st radiation element of the said 2nd radiation element WHEREIN: In the area containing the other end of the said 2nd radiation element, as the said other end approaches, the said edge A curve gradually moving away from the first radiating element is drawn, and an outer edge of the third radiating element facing the first radiating element approaches the other end in a section including the other end of the third radiating element. It is preferable to draw a curve gradually moving away from the first radiating element.

  According to the above configuration, since the second and third radiating elements 12 and 13 are configured in this manner, a VSWR valley (a sudden decrease in VSWR) that may occur in the operating band on the high frequency side of the operating band. ) Can be suppressed.

  In the antenna according to one aspect of the present invention, the outer edge of the second radiating element on the side opposite to the side facing the first radiating element is in the section including the one end of the second radiating element. A curve that gradually approaches the first radiating element as the distance from the first radiating element approaches is drawn, and the outer edge of the third radiating element opposite to the side facing the first radiating element is defined by It is preferable to draw a curve that gradually approaches the first radiating element as it approaches the one end.

  The antenna can be disposed on a conductor plate represented by an automobile roof or the like. In such a case, since the second and third radiating elements are configured as described above, the capacitance generated between the second radiating element and the conductor plate, and the third radiating element, The value of the capacitance generated between the conductor plate can be easily set as appropriate. Therefore, the VSWR is prevented from being lowered due to the arrangement on the conductor plate, and the VSWR is easily flattened in a wide operation band.

  In the antenna according to one aspect of the present invention, in the section including the one end of the first radiating element, the section being longer than the width of the first radiating element, the first radiating element and the second radiating element. The distance between the radiating element and the distance between the first radiating element and the third radiating element is constant so that the impedance of the antenna matches the characteristic impedance of the feeder line. It is preferable that

  According to said structure, the impedance of this antenna and the characteristic impedance (for example, 50 (ohm)) of a feeder can be matched easily. Therefore, the present antenna can suppress reflection due to impedance mismatch and obtain a high gain.

  The present invention can provide an antenna having a compact size and a wider operating band than a conventional antenna.

(A) is a top view of the antenna which concerns on the 1st Embodiment of this invention. (B) is sectional drawing of the antenna shown to (a). It is a top view of the 1st example of the present invention. 3 is a graph showing the frequency dependence of the gain and VSWR of the antenna shown in FIG. 2. (A) And (b) is a graph which shows the azimuth | direction dependence of the gain in the antenna of the 1st and 2nd Example. It is a section perspective view of the antenna concerning a 2nd embodiment of the present invention. It is a top view of the 1st-3rd radiating element with which the 2nd Example of this invention is equipped. It is a graph which shows the frequency dependence of the gain of each Example of this invention. It is a three-view figure of the antenna which concerns on the 3rd Embodiment of this invention. It is an enlarged plan view of the antenna shown in FIG. It is a top view of the 1st-3rd radiating element, a ground plane, and the 2nd U-shaped conductor pattern with which the 3rd example of the present invention is provided. It is a graph which shows the gain dependence of the antenna shown in FIG. 10, and the frequency dependence of VSWR. It is a perspective view of the 1st reference example of the antenna shown in FIG. It is a graph which shows the gain dependence of the antenna shown in FIG. 12, and the frequency dependence of VSWR. It is a perspective view of the 2nd reference example of the antenna shown in FIG.

[First Embodiment]
An antenna according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1A is a plan view of the antenna 10 according to the present embodiment. FIG. 1B is a cross-sectional view of the antenna 10 and shows a cross section taken along the line AA shown in FIG.

  As shown in FIG. 1, the antenna 10 includes a radiating element 11 that is a first radiating element, a radiating element 12 that is a second radiating element, a radiating element 13 that is a third radiating element, and a dielectric substrate. 14 and a connector 15. Each of the radiating elements 11 to 13 is made of a metal (for example, copper) conductive foil, and is formed on one surface of the dielectric substrate 14. The radiation element 12 and the radiation element 13 are arranged so as to sandwich the radiation element 11.

  The radiating element 11 is a radiating element whose operating band is the frequency band on the low frequency side. The electrical length of the radiating element 11 is determined so as to correspond to the 698 MHz electromagnetic wave that is the first resonance point. The electrical length of the radiating element 11 corresponds to the length of the distance between the one end 11a and the other end 11b of the radiating element 11 along the central axis 11e.

  Each of the radiating elements 12 and 13 is a radiating element whose operating band is a frequency band on the high frequency side. The electrical length of the radiating element 12 is determined so as to correspond to the electromagnetic wave of 1420 MHz that is the second resonance point. The electrical length of the radiating element 13 is determined so as to correspond to an electromagnetic wave of 2000 MHz that is the third resonance point. Therefore, the electrical length of the radiating element 12 and the electrical length of the radiating element 13 are shorter than the electrical length of the radiating element 11. The electrical lengths of the radiating elements 12 and 13 correspond to the lengths of the outer edge 12d of the radiating element 12 and the outer edge 13d of the radiating element 13, respectively. The antenna 10 is assumed to be used in a frequency band from 698 MHz to 2690 MHz, that is, a so-called LTE frequency band.

  The center axis 11e, the outer edge 12d, and the outer edge 13d will be described later.

  The radiating elements 12 and 13 are arranged so as to sandwich the radiating element 11. Therefore, the antenna 10 is as compact as a conventional antenna.

  The electrical length of each of the radiating elements 12 and 13 is shorter than the electrical length of the radiating element 11. That is, the antenna 10 has a first resonance point corresponding to the electrical length of the radiating element 11 and second and third resonance points respectively corresponding to the electrical lengths of the second and third radiating elements. . By setting the first resonance point to 698 MHz, the second resonance point to 1420 MHz, and the third resonance point to 2000 MHz, the antenna 10 has a desired frequency band of 698 MHz to 2690 MHz. The frequency band can be an operating band.

  Further, in the antenna 10, each of the radiating elements 12 and 13 is disposed so as to sandwich the radiating element 11. According to this configuration, the capacitance value generated between the radiating element 11 and the radiating element 12 and the capacitance value generated between the radiating element 11 and the radiating element 13 can be easily controlled. Therefore, the antenna 10 can prevent the VSWR from increasing in a specific band among the desired frequency bands. Therefore, the antenna 10 can make most of the LTE frequency band, which is a desired frequency band, the operating band. In the present specification, the frequency band where VSWR is 2 or less is defined as the operating band of the antenna.

  As described above, the antenna 10 can provide an antenna having a compact size and a wider operating band than a conventional antenna.

  The connector 15 connects the antenna 10 and a coaxial cable (not shown in FIG. 1). The coaxial cable is an example of a feeder line described in the claims. The coaxial cable includes an inner conductor, an outer conductor, an insulating layer that insulates the inner conductor from the outer conductor, and a covering layer that covers the outer side of the outer conductor. Each of the inner conductor and the outer conductor corresponds to one conductor and the other conductor recited in the claims, respectively.

  The connector 15 includes a center conductor, an outer conductor, and an insulator that insulates the center conductor and the outer conductor. The center conductor of the connector 15 electrically connects the inner conductor of the coaxial cable to the one end 11 a of the radiating element 11. The outer conductor of the connector 15 electrically connects the outer conductor of the coaxial cable to both one end 12 a of the radiating element 12 and one end 13 a of the radiating element 13. Therefore, the radiating element 12 and the radiating element 13 are short-circuited via the outer conductor of the connector 15. The radiating element 11 is insulated from the radiating elements 12 and 13.

  According to said structure, when arrange | positioning so that the longitudinal direction of the radiation element 11 may be followed with respect to the extending | stretching direction of a coaxial cable, the antenna 10 and a coaxial cable can be easily connected via the connector 15. FIG. . The arrangement of the radiating element 11 and the radiating elements 12 and 13 arranged so as to sandwich the radiating element 11 corresponds to the arrangement of the inner conductor of the coaxial cable and the outer conductor arranged so as to surround the inner conductor. It is.

(Radiation element 11)
As shown to (a) of FIG. 1, the radiation element 11 is the conductor foil shape | molded by the cup shape which has the head part 11c and the neck part 11d. The neck portion 11d extends from the end side of the neck portion 11d opposite to the head portion 11c side toward the head portion 11c. This end side is also one end 11 a of the radiating element 11.

  The width W11 of the neck portion 11d (see FIG. 1B) is constant in (1) a section having a predetermined length including the one end 11a, and (2) one end between the section and the head 11c. The width is gradually increased from 11a toward the other end 11b. In the present embodiment, the outer edge of the radiating element 11 excluding the one end 11a and the other end 11b is constituted by a smoothly continuous curve.

  The neck 11 d is connected to the connector 15 at one end 11 a. As shown in FIG. 1B, the second radiating element 12 and the third radiating element 13 are arranged so as to sandwich the neck portion 11d of the radiating element 11.

  According to said structure, each of the radiation elements 12 and 13 which pinch | interpose the radiation element 11 can be arrange | positioned in the space formed in the both sides of the neck part 11d of the radiation element 11. FIG. Therefore, compared with the case where the radiating element 11 is not provided with the neck portion 11d (for example, a rectangular shape), the present antenna can reduce the width of the region required for installing the antenna. That is, the antenna 10 can be installed (accommodated) in a more compact space.

(Radiation elements 12, 13)
As shown in FIG. 1 (a), the outer edge of the radiating element 12 is (1) an end which is one end 12a, (2) an outer edge 12c facing the radiating element 11, and (3) facing the radiating element 11. And an outer edge 12d on the opposite side. The outer edge 12c is connected to the end of the end that is the one end 12a on the side of the radiating element 11, and the outer edge 12d is connected to the end of the end that is opposite to the radiating element 11 side. The outer edge 12 c and the outer edge 12 d are separated by the other end 12 b of the radiating element 12.

  Similarly, the outer edge of the radiating element 13 includes (1) an end which is one end 13a, (2) an outer edge 13c facing the radiating element 11, and (3) an outer edge 13d opposite to the side facing the radiating element 11. And is composed of. The outer edge 13c is connected to the end of the one end 13a on the radiating element 11 side, and the outer edge 13d is connected to the end of the end opposite to the radiating element 11 side. The outer edge 13 c and the outer edge 13 d are separated by the other end 13 b of the radiating element 13.

  The outer edge 12c of the radiating element 12 draws a curve that gradually moves away from the radiating element 11 as it approaches the other end 12b in a section including the other end 12b.

  Similarly, the outer edge 13c of the radiating element 13 draws a curve that gradually moves away from the radiating element 11 as it approaches the other end 13b in the section including the other end 13b.

  By configuring the radiating elements 12 and 13 in this manner, a gain valley (2000 MHz in the embodiment shown in FIG. 3) that can occur in the frequency band (2000 MHz to 2690 MHz) on the high frequency side of the LTE frequency band. As described above, a sudden drop in gain existing at 2150 MHz or less can be suppressed.

(Impedance of antenna 10)
As described above, the width W11 of the neck portion 11d is constant in the section having a predetermined length including the one end 11a of the radiating element 11. That is, the width W11 in the section is equal to the width W11 at the one end 11a. The length of the section is longer than the width W11.

  In this section, the interval D12 between the neck portion 11d and the radiating element 12 and the interval D13 between the neck portion 11d and the radiating element 13 are constant. As described above, the radiating element 11 is connected to the inner conductor of the coaxial cable, and the radiating elements 12 and 13 are connected to the outer conductor of the coaxial cable. Therefore, the radiating element 11 and the radiating elements 12 and 13 have a coplanar structure at least in the section having the predetermined length.

  In the antenna 10, the impedance of the antenna 10 and the characteristic impedance (for example, 50Ω) of the coaxial cable are matched by adjusting the distance D12 and the distance D13 and the length of the section where the distance D12 and the distance D13 are constant. be able to. Therefore, the antenna 10 can suppress reflection caused by impedance mismatch at the feeding point.

  The antenna 10 can adjust the impedance by adjusting the distance D12 and the distance D13 and the length of the section having a predetermined length. Therefore, the antenna 10 can be connected to a coaxial cable having various characteristic impedances with impedance matching.

(Inclination angle of the central axis 11e of the neck portion 11d)
The dashed-dotted line shown in FIG. 1 shows the central axis 11e of the neck part 11d. The radiating element 11 is configured so that the end of the head 11c opposite to the neck 11d side (that is, the other end 11b of the radiating element 11) and the central axis 11e are not orthogonal to each other. Therefore, the angle θ formed by the central axis 11e and the other end 11b is an acute angle. In the present embodiment, the central axis 11e is inclined away from the radiating element 12 and closer to the radiating element 13 as it approaches the other end 11b from the one end 11a. However, the direction in which the central axis 11e is inclined may be a direction away from the radiating element 13 and approaching the radiating element 12 as the end 11a approaches the other end 11b.

  Since the central axis 11e and the other end 11b are not orthogonal to each other, the length of the other end 11b can be made longer than in the case where they are orthogonal to each other. Therefore, the gain with respect to the horizontal polarization of the antenna 10 can be improved. As will be described later with reference to FIG. 7, the inclination angle (90 ° −θ) with respect to the normal line of the other end 11b of the central axis 11e is preferably 10 ° or more and 30 ° or less.

  Further, since the central axis 11e is inclined with respect to the normal line of the other end 11b, it is possible to suppress a decrease in gain with respect to horizontal polarization in a specific direction.

  In the present embodiment, the radiating element 11 is connected to the inner conductor of the coaxial cable, and the radiating elements 12 and 13 are connected to the outer conductor of the coaxial cable. However, a configuration in which the radiating element 11 is connected to the outer conductor of the coaxial cable and the radiating elements 12 and 13 are connected to the inner conductor of the coaxial cable may be employed.

(When placed on a conductor plate)
The antenna 10 can be suitably disposed on a conductor plate typified by an automobile roof or the like. When the antenna 10 is arranged on the conductor plate, (1) the radiating element 11 connected to the inner conductor of the coaxial cable is insulated from the conductor plate, and (2) connected to the outer conductor of the coaxial cable. The radiating elements 12 and 13 are preferably arranged so as to be short-circuited to the conductor plate.

  In such a case, the outer edge 12d of the radiating element 12 preferably draws a curve that gradually approaches the radiating element 11 as it approaches the one end 12a in the section including the one end 12a, and the outer edge 13d of the radiating element 13 has one end In the section including 13a, it is preferable to draw a curve that gradually approaches the radiating element 11 as it approaches the one end 13a (see FIG. 1).

  According to this configuration, the capacitance generated between the radiating element 12 and the conductor plate and the capacitance generated between the radiating element 13 and the conductor plate can be easily set as appropriate. Therefore, the VSWR is prevented from being lowered due to the arrangement on the conductor plate, and the VSWR is easily flattened in a wide operation band.

  The antenna 10 may further include a conductor plate (or conductor layer) that can fix the dielectric substrate 14 upright. In this case, it is preferable that both the radiating elements 12 and 13 are short-circuited to the conductor plate. The outer conductor of the connector is preferably short-circuited with the conductor plate. It is preferable that an opening is provided on the surface of the conductor plate at a position corresponding to the inner conductor of the connector. The radiating element 11 is preferably insulated from the radiating elements 12 and 13 and the ground layer while being connected to the internal conductor of the connector through this opening.

[First embodiment]
FIG. 2 is a plan view of an embodiment of the antenna 10 shown in FIG. 1, which is the first embodiment of the present invention. In FIG. 2, the connector 15 is omitted and not shown. Each of the radiating elements 11, 12, and 13 provided in the antenna 10 of this embodiment is configured as shown in FIG. In the antenna 10 of the present embodiment, the angle formed by the central axis 11e and the other end 11b is 70 °. That is, the angle formed by the central axis 11e and the normal line of the other end 11b (hereinafter referred to as the inclination angle of the central axis) is 20 °. The relative dielectric constant of the dielectric substrate 14 is 4.4.

  In this example, the antenna 10 was arranged so that the one end 11a and the other end 11b of the radiating element 11 were along the horizontal plane, and the radiation characteristics (gain and VSWR) were measured. That is, the radiation characteristics were measured by arranging the antenna 10 so that the central axis 11e of the radiating element 11 is inclined by 20 ° with respect to the zenith direction. The gain shown in FIG. 3 is obtained by averaging the gains in each direction in the horizontal plane (zx plane) shown in FIG. Similarly, the VSWR shown in FIG. 3 is obtained by measuring the VSWR for each azimuth and averaging the VSWR for each azimuth.

  FIG. 3 is a graph showing the gain and VSWR obtained by the antenna 10 of this embodiment. Referring to the gain shown in FIG. 3, it was found that the antenna 10 of the present example showed a good gain of −2 dBi or less in a wide frequency band of 900 MHz or more and 2690 MHz or less. Note that one of the conditions to be satisfied by an LTE antenna to be mounted on an automobile as an example of a moving body is that the gain in the LTE frequency band satisfies −6 dBi or more.

  In addition, referring to the VSWR shown in FIG. 3, the antenna 10 of this embodiment has a good VSWR of 2 or less in a wide frequency band of 700 MHz to 1250 MHz and a frequency band of 1500 MHz to 2690 MHz. It was found that That is, the operating band of the antenna 10 of the present embodiment is a frequency band of 700 MHz to 1250 MHz and a frequency band of 1500 MHz to 2690 MHz.

  In the frequency band above 1250 MHz and below 1500 MHz, the VSWR of the antenna 10 of the present embodiment exceeds 2. However, most of the frequency band is included in a frequency band not used for LTE (referred to as an unused band). There are a plurality of unnecessary bands in the LTE frequency band, such as a frequency band exceeding 960 MHz and lower than 1427 MHz, and a frequency band exceeding 1510 MHz and lower than 1710 MHz.

  In the antenna 10, as described above, by defining the shape of the outer edge of the radiating elements 12 and 13, a wide frequency band can be set as the operating band. Further, even when a frequency band slightly exceeding VSWR is generated, most of the frequency band can be superimposed on the unused band. Therefore, the frequency band in which VSWR exceeds 2 does not cause a problem when the antenna 10 is used as an LTE antenna. Thus, the antenna 10 can be suitably used as an antenna for LTE.

  (A) of FIG. 4 is a graph which shows the azimuth | direction dependence of the gain obtained by the antenna 10 of a present Example. 4A, (1) the zenith direction is defined as the y-axis, and (2) the direction parallel to the normal line of the radiating elements 11, 12, 13 and the surface of the dielectric substrate 14 (radiation) The direction from the surface on which the elements 11, 12, and 13 are formed to the back surface of the dielectric substrate 14 is defined as the positive x-axis direction, and (3) is the direction orthogonal to the x-axis and the y-axis. Thus, the direction from the radiating element 13 toward the radiating element 12 is defined as the positive z-axis direction. The frequency of the electromagnetic wave used for the measurement is 960 MHz.

  In FIG. 4A, Eθ represents a gain for horizontal polarization, Eφ represents a gain for vertical polarization, and Etotal represents a gain for all polarizations.

  Referring to FIG. 4A, it can be seen that the antenna 10 has a higher gain with respect to the vertical polarization than a gain with respect to the horizontal polarization. This is because although the central axis 11e of the radiating element 11 has an inclination angle of 20 °, the longitudinal directions of the radiating elements 11, 12, and 13 are arranged along the zenith direction.

  In addition, referring to FIG. 4A, it can be seen that the gain with respect to the horizontal polarization reaches about −10 dB although it is smaller than the gain with respect to the vertical polarization. This is due to the fact that the length of the other end 11b can be secured longer than when the center axis 11e and the other end 11b are orthogonal to each other. Thus, according to the configuration in which the central axis 11e and the other end 11b are not orthogonal to each other, the gain with respect to the horizontal polarization can be increased.

  The configuration in which the central axis 11e and the other end 11b are orthogonal to each other will be described later in the second embodiment (see FIG. 4B).

[Second Embodiment]
An antenna according to an embodiment of the present subject matter is described with reference to FIG. FIG. 5A is a plan view of the antenna 50 according to the present embodiment. FIG. 5B is a cross-sectional view of the antenna 50, and shows a cross section taken along the line AA shown in FIG.

  As shown in FIG. 5, the antenna 50 includes a radiating element 51, a radiating element 52, a radiating element 53, a dielectric substrate 54, and a connector 55.

  The antenna 50 is different from the antenna 10 shown in FIG. 1 in that the central axis 51e of the radiating element 51 and the other end 51b of the radiating element 51 are orthogonal to each other. The antenna 50 is configured in the same manner as the antenna 10 except that the angle θ formed by the central axis 51e and the other end 51b is θ = 90 ° (the inclination angle of the central axis 51e is 0 °).

  Note that (1) each of the radiating elements 51 to 53 included in the antenna 50 corresponds to the radiating elements 11 to 13 included in the antenna 10, and (2) the dielectric substrate 54 included in the antenna 50 is Corresponding to the dielectric substrate 14 provided in the antenna 10, (3) the connector 55 provided in the antenna 50 corresponds to the connector 15 provided in the antenna 10.

[Second Embodiment]
FIG. 6 is a plan view of an embodiment of the antenna 50 shown in FIG. 5 which is the second embodiment of the present invention. In FIG. 6, the connector 55 is omitted and not shown. Each of the radiating elements 51, 52, and 53 provided in the antenna 50 of this embodiment is configured as shown in FIG. In the antenna 50 of the present embodiment, the central axis 51e and the other end 51b are orthogonal. That is, the inclination angle of the central axis 51e is 0 °. The relative dielectric constant of the dielectric substrate 54 is 4.4 like the relative dielectric constant of the dielectric substrate 14.

  In this example, the gain was measured using the same method as the antenna 10 of the first example. That is, the antenna 50 was arranged so that the direction of the central axis 51e of the radiating element 51 was parallel to the zenith direction, and the gain was measured.

[Inclination angle dependence of central axis]
FIG. 4B is a graph showing the azimuth dependency of the gain obtained by the antenna 50 of the present embodiment. The gain of the antenna 50 was measured using the same method as when the gain of the antenna 10 was measured.

  In FIG. 4B, Eθ represents the gain for the horizontal polarization, Eφ represents the gain for the vertical polarization, and Etotal represents the gain for all polarizations.

  Referring to (b) of FIG. 4, it can be seen that the antenna 50 has a significantly lower gain with respect to horizontal polarization than the antenna 10. This is because the central axis 51e and the other end 51b are orthogonal to each other, so that the length of the other end 51b is shorter than that of the antenna 10 that is not orthogonal to each other.

  In other words, the antenna 10 can increase the gain with respect to the horizontally polarized wave because the length of the other end 11b can be secured longer due to the inclination of the central axis 11e.

  FIG. 7 is a graph showing gains obtained by the antenna 10 of the first embodiment, the antenna 50 of the second embodiment, and the modifications of the antenna 10. A modification of the antenna 10 is obtained by setting the angle θ formed by the central axis 11e and the other end 11b to θ = 80 °, that is, the inclination angle of the central axis 11e is 10 ° in the antenna 10 shown in FIG. . The gain shown in FIG. 7 is obtained by measuring the gain for each direction in the horizontal plane (zx plane) and then averaging the gains for each direction.

  The gain shown in FIG. 7 was measured using a measurement system different from the gain shown in FIG. Therefore, the gain of the antenna 10 shown in FIG. 7 is lower than the gain of the antenna 10 shown in FIG. Nevertheless, each of the antenna 10, the antenna 50, and the modification of the antenna 10 shown in FIG. 7 is measured under the same conditions. Referring to FIG. 7, the gains of the antenna 10, the antenna 50, and the modification of the antenna 10 all satisfy the condition of −6 dBi or more in the LTE frequency band. Therefore, all of these antennas are antennas that can be suitably mounted on automobiles.

  In FIG. 7, plots of VgainAVG0 °, VgainAVG10 °, and VgainAVG20 ° are respectively for the vertically polarized waves of the antenna 50 of the second embodiment, the antenna 10 of the first embodiment, and the variation of the antenna 10 respectively. Indicates gain. Each plot of HgainAVG0 °, HgainAVG10 °, and HgainAVG20 ° indicates the gain with respect to the horizontal polarization of the antenna 50 of the second embodiment, the antenna 10 of the first embodiment, and the modification of the antenna 10, respectively. Each plot of EtotalGainAVG0 °, EtotalGainAVG10 °, and EtotalGainAVG20 ° indicates the gain for all polarizations of the antenna 50 of the second embodiment, the antenna 10 of the first embodiment, and the modification of the antenna 10, respectively.

  Referring to the gain with respect to the horizontal polarization shown in FIG. 7, the gain of the antenna 50 with the inclination angle of the central axis 51e being 0 ° is the same as that of the antenna 10 and the central axis 11e with the inclination angle of the central axis 11e being 20 °. It was found that it was significantly lower than the modification of the antenna 10 having an inclination angle of 10 °. In other words, by tilting the central axis 11e of the radiating element 11 from 0 ° to 10 ° and 20 °, the horizontal receiving surface is expanded and the horizontal gain can be improved. However, since the main polarization is vertical polarization, if it is tilted more than necessary, the gain with respect to vertical polarization decreases. In the antenna according to the embodiment of the present invention, the gain with respect to the vertically polarized wave is significantly decreased when the tilt angle exceeds 30 °.

  From the above, in order to increase the gain with respect to the horizontal polarization, the inclination angle of the central axis 11e is preferably greater than 0 ° and not more than 30 °, and more preferably not less than 10 ° and not more than 30 °.

[Third Embodiment]
An antenna according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a trihedral view of the antenna 60 according to the present embodiment. More specifically, the upper left diagram in FIG. 8 is a plan view of the antenna 60, the upper right diagram in FIG. 8 is a right side view of the antenna 60, and the lower left diagram in FIG. It is a front view. FIG. 9 is an enlarged plan view in which the plan view of the antenna 60 is enlarged. In FIG. 9, illustrations of the first to third radiating elements 61 to 63, the dielectric substrate 64, and the coaxial cable 69 included in the antenna 60 are omitted.

  As shown in FIG. 8, the antenna 60 includes a radiating element 61 that is a first radiating element, a radiating element 62 that is a second radiating element, a radiating element 63 that is a third radiating element, and a dielectric substrate. 64, a ground plane 65, a dielectric substrate 66, a U-shaped conductor pattern 67, a dielectric substrate 68, and a coaxial cable 69.

(Radiating elements 61, 62, 63)
Each of the radiating elements 61 to 63 corresponds to the radiating elements 11 to 13 included in the antenna 10 illustrated in FIG. 1. Therefore, each of the radiating elements 61 to 63 is made of a metal (for example, copper) conductive foil, and is formed on one surface of the dielectric substrate 64. The radiation element 62 and the radiation element 63 are arranged so as to sandwich the radiation element 61.

  The radiating element 61 is a radiating element whose operating band is the frequency band on the low frequency side. The electrical length of the radiating element 61 is determined so as to correspond to the 698 MHz electromagnetic wave that is the first resonance point. The electrical length of the radiating element 16 corresponds to the distance between the one end 61 a and the other end 61 b of the radiating element 16. In the present embodiment, the shape of the radiating element 16 is a rectangle (right side view of FIG. 8). Therefore, the electrical length of the radiating element 16 is equal to the length of the long side of the radiating element 16.

  Each of the radiating elements 62 and 63 is a radiating element whose operating band is a frequency band on the high frequency side.

  The radiating element 63 is designed to cope with electromagnetic waves in a frequency band of 1420 MHz or more and less than 1900 MHz including 1420 MHz which is the second resonance point. Specifically, the radiating element 63 includes a radiating element body 63e and a sub-radiating element 63f. The radiating element body 63 e includes one end 63 a of the radiating element 63. The sub-radiating element 63f extends from the end of the radiating element main body 63e and the end opposite to the one end 63a toward the other end 63b of the radiating element 63.

  In the radiating element 63 configured as described above, the electrical length of the outer edge 63d (the electrical length corresponding to the length measured from the one end 63a to the other end 63b along the outer edge 63d) corresponds to the electromagnetic wave of 1420 MHz. It is stipulated in. On the other hand, the electrical length of the outer edge 63c (the electrical length corresponding to the length when measured from one end 63a to the end of the radiating element body 63e along the outer edge 63c) is determined so as to correspond to an electromagnetic wave of 1800 MHz. . In the present embodiment, the shorter one of the electrical length of the outer edge 63c and the electrical length of the outer edge 63d, that is, the electrical length of the outer edge 63c is defined as the electrical length of the radiating element 63.

  The radiating element 62 is designed to cope with electromagnetic waves in a frequency band of 1900 MHz to 2700 MHz including 2000 MHz which is the third resonance point. Specifically, the electrical lengths of the outer edge 62c and the outer edge 62d are determined so as to correspond to an electromagnetic wave of 2000 MHz. When the electrical length of the outer edge 63c is different from the electrical length of the outer edge 63d, the longer one of the electrical length of the outer edge 63c and the outer edge 63d is the electrical length of the radiating element 62.

  As described above, in the antenna 60, the electrical length of the radiating element 62 and the electrical length of the radiating element 63 are shorter than the electrical length of the radiating element 61. Further, the electrical length of the radiating element 63 is shorter than the electrical length of the radiating element 62.

  Further, when compared with the radiating elements 12 and 13 included in the antenna 10, the radiating elements 62 and 63 are designed so that their electrical lengths are clearly different. According to this configuration, the electrical lengths of the radiating elements 62 and 63 are determined so as to further subdivide the LTE frequency band. Therefore, the antenna 60 can further flatten the VSWR in the LTE frequency band.

  The radiating elements 62 and 63 are arranged so as to sandwich the radiating element 61. Therefore, the antenna 60 is as compact as a conventional antenna.

  Further, according to this configuration, the value of the capacitance generated between the radiating element 61 and the radiating element 62 and the value of the capacitance generated between the radiating element 61 and the radiating element 63 can be easily controlled. Therefore, similarly to the antenna 10, the antenna 60 can prevent the VSWR from increasing in a specific band in a desired frequency band. Therefore, the antenna 60 can make most of the LTE frequency band, which is a desired frequency band, the operating band. In the present specification, the frequency band where VSWR is 2 or less is defined as the operating band of the antenna.

  As described above, the antenna 60 can provide an antenna having a compact size and a wider operating band than a conventional antenna.

  In the antenna 10, the coaxial cable is connected to the first to third radiating elements 11 to 13 via the connector 15. On the other hand, in the antenna 60, the coaxial cable 69 is connected to the first radiating element 61 and the third radiating element 63 without using a connector. Specifically, the inner conductor of the coaxial cable 69 is connected (soldered in the present embodiment) to one end 61 a of the first radiating element 61, and the outer conductor of the coaxial cable 69 is the third radiating element 63. Is connected (soldered in this embodiment) to one end 63a. However, the antenna 60 may include a connector for connecting the coaxial cable and the radiating elements 61 and 63 in the same manner as the antenna 10.

(Ground plate 65)
The antenna 60 further includes a ground plane 65 (see FIGS. 8 and 9). The ground plane 65 is made of a conductive foil made of metal (for example, copper), and is formed on one surface of the dielectric substrate 66. The ground plane 65 and the dielectric substrate 66 are arranged so as to intersect with the first to third radiating elements 61 to 63 and the dielectric substrate 64 (in the present embodiment, orthogonal to each other). In other words, the first to third radiating elements 61 to 63 and the dielectric substrate 64 are fixed to stand on the surfaces of the ground plane 65 and the dielectric substrate 66.

  As shown in FIG. 9, the base plate 65 includes a root portion 65d as a first root portion, a root portion 65a as a second root portion, a root portion 65b as a third root portion, and a C-shaped conductor pattern 65c. The first U-shaped conductor pattern 65e is a U-shaped conductor pattern 65e and the first to third rectangular conductor patterns 65f to 65h.

  The root portion 65d is connected (soldered in this embodiment) to one end 61a of the radiating element 61. The root portion 65a is connected (soldered in this embodiment) to one end 62a of the radiating element 62. The root portion 65b is connected (soldered in the present embodiment) to the one end 63a of the radiating element 63.

  The U-shaped conductor pattern 65e is configured by a strip-shaped conductor bent into a U-shape. An end portion 65e1 which is one end portion of the U-shaped conductor pattern 65e is continuous with the root portion 65d, and an end portion 65e2 which is the other end portion of the U-shaped conductor pattern 65e is continuous with the root portion 65a. Yes. Therefore, the one end 61a of the radiating element 61 and the one end 62a of the radiating element 62 are short-circuited via the root portion 65d, the root portion 65a, and the U-shaped conductor pattern 65e constituting the first short-circuit portion.

  The C-shaped conductor pattern 65c is configured by a strip-shaped conductor bent into a C-shape. One end of the C-shaped conductor pattern 65c is continuous with the root portion 65a, and the other end of the C-shaped conductor pattern 65c is continuous with the root portion 65b. In other words, the C-shaped conductor pattern 65c is a conductor pattern that conducts the root portion 65a and the root portion 65b. Therefore, one end 62a of the radiating element 62 and one end 63a of the radiating element 63 are short-circuited via the root portion 65a, the root portion 65b, and the C-shaped conductor pattern 65c.

  The rectangular conductor pattern 65f is a rectangular conductor pattern connected to the upper left end of the C-shaped conductor pattern 65c shown in FIG. 9, and extends in a direction away from the root portion 65d.

  The rectangular conductor pattern 65g is a rectangular conductor pattern continuous to the upper left end of the C-shaped conductor pattern 65c shown in FIG. 9, and extends in a direction orthogonal to the rectangular conductor pattern 65f. The interval between the rectangular conductor pattern 65g and the U-shaped conductor pattern 65e is preferably 10 mm or more. According to this configuration, the gain of electromagnetic waves radiated from the U-shaped conductor pattern 65e can be increased.

  The rectangular conductor pattern 65h is a rectangular conductor pattern continuous to the lower right end of the C-shaped conductor pattern 65c shown in FIG. 9, and extends in a direction away from the root portion 65d.

(Second short-circuit part)
A U-shaped conductor pattern 67 shown in FIG. 9 is a second U-shaped conductor pattern. The U-shaped conductor pattern 67 is made of a conductive foil made of metal (for example, copper) and is formed on one surface of the dielectric substrate 68. The U-shaped conductor pattern 67 and the dielectric substrate 68 intersect with the dielectric substrate 64 (so as to be orthogonal to each other in this embodiment) and intersect with the dielectric substrate 66 (orthogonal in this embodiment). To be arranged). In other words, the U-shaped conductor pattern 67 and the dielectric substrate 68 are one of the dielectric substrates 64 on which the radiating elements 61 to 63 are formed so as to stand on the surfaces of the ground plane 65 and the dielectric substrate 66. It is fixed so as to be orthogonal to the surface.

  The U-shaped conductor pattern 67 is configured by a strip-shaped conductor bent into a U-shape. An end portion 671 that is one end portion of the U-shaped conductor pattern 67 is connected to the root portion 65 d (soldering in the present embodiment), and is an end that is the other end portion of the U-shaped conductor pattern 67. The part 672 is connected (soldered in this embodiment) to the C-shaped conductor pattern 65c. Therefore, (1) one end 61a of the radiating element 61 and one end 62a of the radiating element 62 are short-circuited via the root portion 65d, the root portion 65a, and the C-shaped conductor pattern 65c, and (2) the radiating element 61 One end 61a of the radiating element 63 and one end 63a of the radiating element 63 are short-circuited via a root portion 65d, a root portion 65b, and a C-shaped conductor pattern 65c. In the present embodiment, the root portion 65d, the root portion 65a, the root portion 65b, and the C-shaped conductor pattern 65c constitute a second short-circuit portion.

  It should be noted that the inventors of the present invention provide the antenna gain when the U-shaped conductor pattern constituting the second short-circuit portion is disposed along the dielectric substrate 64 and intersects the dielectric substrate 66. It was confirmed that the frequency dependence of VSWR deteriorated.

(Effect of antenna 60)
As described above, the antenna 60 includes the first short-circuit portion and the second short-circuit portion, and each of the first short-circuit portion and the second short-circuit portion functions as a radiating element. According to this configuration, the antenna 60 can improve the gain in the frequency band of 698 MHz to 900 MHz as compared with the antenna 10.

  Further, the first short-circuit portion has an annular structure although a part thereof is not completely closed. Therefore, the first short-circuit portion can improve the gain with respect to the polarization in the direction intersecting with the central axis of the radiating element 61. That is, the antenna 60 includes the first short-circuit portion, thereby improving the gain with respect to the polarization in the direction intersecting the central axis of the neck without impairing the gain with respect to the polarization in the direction along the central axis of the neck. Can be made.

  In the antenna 60, the outer edge 62d of the radiating element 62 draws a curve that gradually approaches the radiating element 61 as it approaches the one end 62a in the section including the one end 62a of the radiating element 62. In a section including the one end 63a, it is preferable to draw a curve that gradually approaches the radiating element 61 as it approaches the one end 63a.

  Further, in the antenna 60, the interval including the one end 61 a of the radiating element 61 and longer than the width of the radiating element 61, the distance between the radiating element 61 and the radiating element 62, and the radiating element 61 and the radiating element 63. Is preferably constant so that the impedance of the antenna 60 matches the characteristic impedance of the coaxial cable 69.

  According to these configurations, the antenna 60 has the same effect as the antenna 10.

(Impedance of antenna 60)
As in the case of the antenna 10 shown in FIG. 1, the antenna 60 has an interval between the radiating element 61 and the radiating element 62, an interval between the radiating element 61 and the radiating element 63, and a section having a predetermined length. The impedance can be adjusted by adjusting the length of. In addition to the above-described impedance adjustment, the antenna 60 can perform the impedance adjustment using the following method.

  As shown in FIG. 9, the root portion 65d is composed of a rectangular conductor pattern 65d1 and a rectangular conductor pattern 65d2. By changing the size of the rectangular conductor pattern 65d2 and the size of the root portion 65a, (1) the distance between the root portion 65d and the root portion 65a and (2) the length of the portions facing each other can be changed. . Further, by changing the size of the rectangular conductor pattern 65d1 and the size of the root portion 65b, (1) the interval between the root portion 65d and the root portion 65b and (2) the length of the portions facing each other are changed. Can do.

  In other words, the impedance of the antenna 60 is adjusted by adjusting the size of the rectangular conductor pattern 65d2 and the size of the root portion 65a, and adjusting the size of the rectangular conductor pattern 65d1 and the size of the root portion 65b. It can be adjusted to a desired value. Therefore, the antenna 60 can easily match its own impedance with the characteristic impedance (for example, 50Ω) of the coaxial cable 69. Therefore, the antenna 60 can easily suppress reflection caused by impedance mismatch at the feeding point.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIGS. The present embodiment is an embodiment of the antenna 60 shown in FIGS. FIG. 10 is a plan view of the radiating elements 61, 62, 63, the ground plane 65, and the U-shaped conductor pattern 67 included in the antenna 60 of this embodiment. FIG. 11 is a graph showing the frequency dependence of the gain and VSWR of the antenna 60 of this embodiment.

  Each of the radiating elements 61, 62, 63, the ground plane 65, and the U-shaped conductor pattern 67 included in the antenna 60 of the present embodiment is configured as shown in FIG. Note that the dielectric constants of the dielectric substrates 64, 66, and 68 are all 4.4, similar to the relative dielectric constant of the dielectric substrate 14.

  In this example, the gain was measured using the same method as the antenna 10 of the first example. That is, the antenna 60 was arranged so that the direction of the central axis of the radiating element 61 was parallel to the zenith direction, and the gain was measured.

  Referring to the gain shown in FIG. 11, it can be seen that the antenna 60 can improve the gain in the frequency band of 698 MHz to 900 MHz to −2 dBi or higher compared to the gain of the antenna 10 shown in FIG. 3. It was.

[First Reference Example]
A first reference example of the present invention will be described with reference to FIGS. FIG. 12 is a perspective view of the antenna 60A of this reference example. FIG. 13 is a graph showing the frequency dependence of the gain and VSWR of the antenna 60A of this reference example.

  The antenna 60A of this reference example is obtained by omitting the U-shaped conductor pattern 67 and the dielectric substrate 68 included in the antenna 60 shown in FIGS. 8 to 9 (see FIG. 12). That is, the antenna 60A includes only the first short-circuit portion and does not include the second short-circuit portion. Except for this point, the antenna 60A of the present reference example is configured in the same manner as the antenna 60 of the third embodiment.

  Referring to the gain shown in FIG. 13, compared with the gain of the antenna 10 shown in FIG. 3, the antenna 60 </ b> A can slightly improve the gain in the frequency band of 698 MHz to 900 MHz. It has been found that the degree of is not as high as that of the antenna 60 of the third embodiment.

  Nevertheless, it has been found that even when the configuration of the antenna 60A is adopted, it is possible to provide an antenna having a compact size and a wider operating band than a conventional antenna.

[Second Reference Example]
A second reference example of the present invention will be described with reference to FIG. FIG. 14 is a perspective view of the antenna 60B of this reference example.

  The antenna 60B of the present reference example can be obtained by changing the ground plane 65 provided in the antenna 60 shown in FIGS. The ground plane 165 is obtained by omitting the U-shaped conductor pattern 65e from the configuration of the ground plane 65 (see FIG. 14). That is, the antenna 60B includes only the second short-circuit portion and does not include the first short-circuit portion. Except for this point, the antenna 60B of the present reference example is configured in the same manner as the antenna 60 of the third embodiment.

  The gain of the antenna 60B was measured. As a result, compared with the gain of the antenna 10 shown in FIG. 3, the antenna 60B can slightly improve the gain in the frequency band of 698 MHz or more and 900 MHz or less. It turns out that it is not as much as the antenna 60 of the example.

  Nevertheless, it has been found that even when the configuration of the antenna 60A is adopted, it is possible to provide an antenna having a compact size and a wider operating band than a conventional antenna.

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

10 Antenna 11, 12, 13 Radiating element (first to third radiating elements)
11a, 12a, 13a One end 11b, 12b, 13b The other end 11c Head 11d Neck 11e Central axis 12c, 13c Outer edge (outer edge facing first radiation element)
12d, 13d outer edge (outer edge opposite to the side facing the first radiating element)
14 Dielectric Substrate 15 Connector 60, 60A, 60B Antenna 61-63 Radiation Element (First to Third Radiation Elements)
61a, 62a, 63a One end 61b, 62b, 63b The other end 62c, 63c Outer edge (outer edge facing the first radiating element)
62d, 63d outer edge (outer edge opposite to the side facing the first radiating element)
63e Radiation element body 63f Sub-radiation element 64 Dielectric substrate (first dielectric substrate)
65,165 Base plate 65a Root part (second root part, part of the first short-circuit part)
65b Root (third root)
65c C-shaped conductor pattern (part of the first short-circuit part)
65d Root part (first root part, part of first and second short-circuit parts)
65e U-shaped conductor pattern (first U-shaped conductor pattern, part of the first short-circuited portion)
65e1, 65e2 End portions 65f to 65h First to third rectangular conductor patterns 66 Dielectric substrate (second dielectric substrate)
67 U-shaped conductor pattern (second U-shaped conductor pattern, part of second short-circuited portion)
671, 672 End 68 Dielectric substrate (third dielectric substrate)

Claims (13)

A first radiating element;
A second radiating element and a third radiating element having an electrical length shorter than that of the first radiating element, the second radiating element and the third radiating element being arranged so as to sandwich the first radiating element. An element,
An antenna characterized by that. One conductor constituting the feeder line is connected to one end of the first radiating element, and the other conductor constituting the feeder line is connected to one end of the second radiating element and one end of the third radiating element. Has a connector to connect to both,
The antenna according to claim 1. The outer edge of the second radiating element that faces the first radiating element has a curve that gradually moves away from the first radiating element as it approaches the other end in a section including the other end of the second radiating element. draw,
The outer edge of the third radiating element that faces the first radiating element has a curve that gradually moves away from the first radiating element as it approaches the other end in a section including the other end of the third radiating element. Draw,
The antenna according to claim 2. The outer edge of the second radiating element on the side opposite to the side facing the first radiating element is in the section including the one end of the second radiating element. Draw a gradually approaching curve,
The outer edge of the third radiating element on the side opposite to the side facing the first radiating element is connected to the first radiating element as it approaches the one end in a section including the one end of the third radiating element. Draw a gradually approaching curve,
The antenna according to claim 2 or 3, wherein The first radiating element is a cup type having a head and a neck, and an end of the neck opposite to the head is connected to the connector as the one end,
The second radiating element and the third radiating element are arranged so as to sandwich a neck portion of the first radiating element,
The antenna according to any one of claims 2 to 4, characterized in that: In a section including the one end of the first radiating element and longer than the width of the neck, the distance between the neck and the second radiating element, and the neck and the third radiating element And the interval is fixed, and the interval is determined so that the impedance of the antenna matches the characteristic impedance of the feeder line,
The antenna according to claim 5. The end of the head opposite to the neck side is not orthogonal to the central axis of the neck,
The antenna according to claim 5 or 6. A first short-circuit portion that short-circuits one end of the first radiating element and one end of the second radiating element;
A second circuit that short-circuits the one end of the first radiating element and the one end of the second radiating element and short-circuits the one end of the first radiating element and the one end of the third radiating element; And a short-circuit part.
The antenna according to claim 1. (1) a first root part connected to one end of the first radiating element; (2) a second root part connected to one end of the second radiating element; and (3) the third part. A third root portion connected to one end of the radiating element, and (4) a C-shaped conductor pattern connecting the second root portion and the third root portion,
The first short-circuit portion includes the first root portion, the second root portion, and a first U-shaped conductor pattern that connects the first root portion and the second root portion. Configured,
The second short-circuit portion includes the first root portion, the second root portion, the third root portion, the C-shaped conductor pattern, and the first root portion and the C-shaped conductor. It is comprised by the 2nd U-shaped conductor pattern which connects a pattern,
The antenna according to claim 8. The electrical length of the second radiating element and the electrical length of the third radiating element are different from each other,
Of the second radiating element and the third radiating element, the radiating element having the longer electrical length is
A radiating element body including one end of the radiating element having the longer electrical length;
A sub-radiating element that extends from the end of the radiating element body that is opposite to one end of the radiating element having the longer electrical length toward the other end of the radiating element having the longer electrical length And consists of,
The antenna according to claim 9. The outer edge of the second radiating element that faces the first radiating element has a curve that gradually moves away from the first radiating element as it approaches the other end in a section including the other end of the second radiating element. draw,
The outer edge of the third radiating element that faces the first radiating element has a curve that gradually moves away from the first radiating element as it approaches the other end in a section including the other end of the third radiating element. Draw,
The antenna according to claim 9 or 10, wherein: The outer edge of the second radiating element on the side opposite to the side facing the first radiating element is in the section including the one end of the second radiating element. Draw a gradually approaching curve,
The outer edge of the third radiating element on the side opposite to the side facing the first radiating element is connected to the first radiating element as it approaches the one end in a section including the one end of the third radiating element. Draw a gradually approaching curve,
The antenna according to any one of claims 9 to 11, characterized in that: In the section including the one end of the first radiating element, the section being longer than the width of the first radiating element, the interval between the first radiating element and the second radiating element, and The distance between the first radiating element and the third radiating element is constant, and the distance is determined so that the impedance of the antenna matches the characteristic impedance of the feeder line.
The antenna according to any one of claims 9 to 12.

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