JP5593278B2 - Multi-frequency shared antenna and antenna device - Google Patents

Description

  The present invention relates to a multi-frequency shared antenna and an antenna device.

  In mobile communication or the like, a plurality of frequency bands such as an 800 MHz band and a 2.0 GHz band are assigned as frequency bands used for communication. For this reason, it is advantageous if one antenna can be shared by a plurality of frequencies. Patent Document 1 describes a multi-frequency antenna that can share one antenna at a plurality of frequencies.

JP 2006-229337 A

The multi-frequency shared antenna described in Patent Document 1 has a plurality of dipole elements that radiate radio waves of different frequencies. The dipole element requires a length of about ½ wavelength at the communication frequency as the element length (length in the longitudinal direction of the dipole element).
For this reason, a multi-frequency shared antenna having a plurality of dipole elements has a length of about ½ wavelength of the maximum wavelength at a plurality of frequencies used for communication in the longitudinal direction of the dipole element. Easy to convert. When the antenna becomes large, the wind receiving area (load) becomes large, and there is a problem that a solid antenna mounting support is required.

  Therefore, an object of the present invention is to provide a multi-frequency shared antenna that can be reduced in size as compared with the prior art.

(1) The present invention is a multi-frequency shared antenna including a plurality of antenna elements that resonate at different frequencies, and includes a dipole element and a loop-shaped antenna element as the plurality of antenna elements, The loop-shaped antenna element is an antenna element that resonates at least at the lowest frequency among the plurality of antenna elements, and the dipole element is disposed on an outer peripheral side of the loop-shaped antenna element, and the loop-shaped antenna element It is a multi-frequency shared antenna that is not arranged on the inner peripheral side of the antenna.

  When a plurality of antenna elements are composed of only dipole elements, the antenna element that resonates at the lowest frequency causes an increase in size and has a size of about ½ wavelength. On the other hand, according to the present invention, since the antenna element that resonates at the lowest frequency causing the increase in size is configured by the loop-shaped antenna element, the size can be reduced.

(2) A line extending from a feeding point is formed and connected to each of the plurality of antenna elements, and the line extends from the feeding point provided on the inner peripheral side of the loop-shaped antenna. It is preferable to include a first line that reaches the antenna element, and a second line that is formed to extend to the outer peripheral side of the loop-shaped antenna element to reach the dipole element. In this case, the antenna configuration can be simplified.

(3) It is preferable that the dipole element, the loop-shaped antenna element, and the line are formed on the same substrate.

(4) It is preferable to further include a reflecting plate provided behind the plurality of antenna elements, and a parasitic element disposed between the reflecting plate and the dipole element.

(5) From another viewpoint, the present invention provides a first multi-frequency shared antenna for horizontal polarization using the multi-frequency shared antenna described in (1) above, and the multi-frequency shared antenna described in (1) above. And a second multi-frequency antenna for vertical polarization using a first multi-frequency antenna, wherein the first multi-frequency antenna includes a first reflector formed so as not to reflect vertical polarization but to reflect horizontal polarization. The second multi-frequency shared antenna includes a second reflector formed so as not to reflect horizontally polarized waves but to reflect vertically polarized waves, the first multi-frequency shared antenna and the second multi-frequency shared antenna The antenna device is characterized in that the first reflector plate and the second reflector plate are arranged so as to overlap each other by making the positions of the first reflector plate and the second reflector plate different from each other. In this case, the multi-frequency shared antenna can be arranged in an overlapping manner.

(6) The loop-shaped antenna element of the first multi-frequency shared antenna has a first cut portion electrically cut in the middle of the loop, and the loop-shaped antenna element of the second multi-frequency shared antenna Preferably has a second cut portion electrically cut in the middle of the loop.
In this case, when a current is passed through one loop-shaped antenna element among the loop-shaped antenna elements of the first multi-frequency shared antenna and the second multi-frequency shared antenna, the other loop-shaped is caused by the current flow. The induced portion can be prevented from flowing through the antenna element by the cutting portion. Thereby, it can suppress that a 1st multifrequency shared antenna and a 2nd multifrequency shared antenna mutually interfere with an induced current.

(7) The first multi-frequency shared antenna includes a pair of line elements that extend in different directions from the feeding point and have the same length, and are connected to different positions in the loop-shaped antenna element. The second multi-frequency shared antenna includes a pair of line elements that extend in different directions from the feeding point and have the same length as each other, and are connected to different positions in the loop-shaped antenna element, Of the pair of line elements of the first multi-frequency common antenna, the path length from the connection point between one line element and the loop-shaped antenna element to the first cut portion, the other line element and the loop-shaped element The path length from the connection point with the antenna element to the first cut portion is set to be substantially the same length, and the pair of line elements of the second multi-frequency shared antenna Among these, the path length from the connection point between one line element and the loop-shaped antenna element to the second cut portion, and the second cut from the connection point between the other line element and the loop-shaped antenna element. It is preferable that the path length to the part is set to be substantially the same length.
In this case, the first and second cut portions pass through one of the line elements from the feed point to the first and second cut portions, and the first and second cut portions pass through the other line element from the feed point. Since the path length to the second cut portion is substantially the same length, that is, the position where current does not flow originally, the first and second multi-frequency shared antennas have the cut portion even if they have the cut portion. Antenna characteristics equivalent to those in the case of not having can be realized.

  According to the present invention, the multi-frequency shared antenna can be reduced in size.

1 is a perspective view of a multi-frequency antenna according to a first embodiment. It is a side view of the antenna main body of 1st Embodiment. It is a perspective view of the multifrequency antenna according to the first comparative example. It is the VSWR characteristic of the antenna of 1st Embodiment. It is horizontal surface directionality of the antenna of 1st Embodiment. It is a VSWR characteristic of the antenna of the 1st comparative example. It is a horizontal plane directivity of the antenna of the 1st comparative example. It is a perspective view of the multifrequency common antenna which concerns on 2nd Embodiment. It is a typical side view of the antenna of 2nd Embodiment. It is the VSWR characteristic of the antenna of 2nd Embodiment. It is horizontal surface directionality of the antenna of 2nd Embodiment. It is a perspective view of the multifrequency shared antenna of the third embodiment. It is a typical side view of the antenna of 3rd Embodiment. It is a typical side view of the antenna of 4th Embodiment. It is a typical side view of the antenna of 5th Embodiment. It is a perspective view of an antenna device (6th Embodiment). It is a typical top view of a comparative example. It is a perspective view of the 1st multi-frequency common antenna for horizontal polarization. It is a VSWR characteristic of the first multi-frequency shared antenna for horizontal polarization. This is the horizontal plane directivity of the first multi-frequency shared antenna for horizontally polarized waves. It is a perspective view of the 2nd multi-frequency common antenna for vertically polarized waves. It is a perspective view of an antenna device (seventh embodiment). It is a perspective view of the 1st multi-frequency common antenna for horizontal polarization. It is a perspective view of the 2nd multi-frequency common antenna for vertically polarized waves. It is a reflection characteristic of the 1st multi-frequency common antenna for horizontal polarization. It is a reflection characteristic of the 2nd multi-frequency common antenna for vertically polarized waves. This is the horizontal plane directivity of the first multi-frequency shared antenna for horizontally polarized waves. This is the vertical plane directivity of the first multi-frequency antenna for horizontal polarization. This is the horizontal plane directivity of the second multi-frequency common antenna for vertical polarization. It is the directivity of the vertical plane of the second multi-frequency common antenna for vertical polarization. It is a perspective view of the multifrequency antenna which shows other embodiment of this invention. FIG. 32 is a perspective view of a multi-frequency common antenna showing a modification of FIG. 31.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[1. First embodiment and first comparative example]
1 and 2 show a multi-frequency antenna 1 according to the first embodiment. The multi-frequency shared antenna 1 is preferably used as an antenna (transmission / reception antenna) of a base station that performs wireless communication with a mobile terminal such as a mobile phone. The antenna 1 of the first embodiment is for horizontal polarization, but can also be used for vertical polarization.

  The multi-frequency antenna 1 includes an antenna body 10 having a plurality of antenna elements (radiating elements) 11, 12, and 13 and a power feeding unit 20 that feeds power to a feeding point 15 of the antenna body 10 having a plurality of antenna elements 11, 12, and 13. And a reflector 30 provided behind the antenna body 10. The power feeding unit 20 is disposed so as to penetrate the reflecting plate 30 from behind the reflecting plate 30 and reach the feeding point 15.

  The plurality of antenna elements 11, 12, and 13 are provided in three types in order to resonate at three frequencies of 800 MHz, 1.5 GHz, and 2.0 GHz and radiate radio waves of those frequencies. The number of antenna elements is not particularly limited as long as it is plural.

Of the plurality of antenna elements 11, 12, and 13, the first antenna element 11 corresponding to the lowest frequency (800 MHz) is formed as a loop antenna element (loop antenna element). This loop antenna element 11 is a one-wavelength loop antenna. That is, the circumference of the first antenna element 11 (the length of one loop) has a length corresponding to about one wavelength of 800 MHz (λ _800M = 356 mm).
The illustrated loop antenna element 11 is formed as a rectangular loop, and the length of the short side 11a is set to 60 mm, and the length of the long side 11b is set to 118 mm.
Note that the specific shape and dimensions of the loop antenna element 11 are not particularly limited, and other shapes such as a circular or elliptical loop may be employed.

The antenna body 10 has a feeding point 15 inside the first antenna element 11 that is a loop antenna element (almost the center of the first antenna element 11). A power feeding part (feeding line) 20 is connected to the power feeding point 15. The illustrated feeder 20 is a parallel two-wire type, but may be a coaxial cable or the like. In the power supply unit 20, signals having a plurality of frequencies flow in a mixed state.
As shown in FIG. 2, the antenna elements 11, 12, and 13, the feeding point 15, and the later-described line 16 constituting the antenna body 10 are formed on a planar substrate 10a as shown in FIG. . In FIG. 1, the substrate 10a is omitted.

  The second and third antenna elements 12, 13 which are other antenna elements in the plurality of antenna elements 11, 12, 13 are formed as dipole elements.

The second antenna element 12 corresponds to a frequency of 1.5 GHz. The second antenna elements 12 are arranged in pairs on both sides of the first antenna element 11 that is the loop antenna element 11. The second antenna element 12, which is a dipole element, has a length in the longitudinal direction (element length) of about ½ (= λ _1.5G / 2 = 102 mm) of a wavelength (λ _1.5G ) of _1.5 GHz. is there.

The third antenna element 13 corresponds to a frequency of 2.0 GHz. The third antenna element 13 is also arranged in pairs on both sides of the first antenna element 11. The third antenna element 13, which is a dipole element, has a length in the longitudinal direction (element length) of about ½ (= λ _2.0G / 2 = 78 mm) of a wavelength (λ _2.0G ) of _2.0 GHz. is there.
The third antenna element 13 is disposed between the loop-shaped first antenna element 11 and the second antenna element 12 that is a dipole element.

The antenna body 10 includes a line 16 that extends from the feeding point 15 toward the antenna elements 11, 12, and 13 and is connected to the antenna elements 11, 12, and 13. The line 16 starts from the feeding point 15 and reaches each of the pair of second antenna elements 12 and 12 located on the outermost side of the antenna body 10. The line 16 of this embodiment is formed in a straight line.
The total length of the line 16 (the length from one second antenna element 12 to the other second antenna element 12 = the element interval between the second antenna elements 12 and 12) is λ _1.5G / 2 = 102 mm. The length from the feeding point 15 to one of the second antenna elements 12 and the length from the feeding point 15 to the other second antenna element 12 are λ _1.5G / 4 = 51 mm.

The pair of third antenna elements 13 is provided on the line 16 at a position of λ _2.0G / 4 = 42 mm from the feeding point 15. That is, the length from one third antenna element 13 to the other third antenna element 13 (element spacing between the third antenna elements 13 and 13) is λ _2.0G / 2 = 84 mm.

The loop-shaped first antenna element 11 is provided between the pair of third antenna elements 13 and 13 corresponding to the highest frequency (2.0 GHz) of the plurality of dipole elements 12 and 13.
The rectangular loop-shaped first antenna element 11 provided between the pair of third antenna elements 13 and 13 is arranged such that the direction along the rectangular short side 11a coincides with the longitudinal direction of the line 16. Is formed. The length of the rectangular short side 11a is 60 mm as described above.
When viewed along the longitudinal direction of the line 16, the distance from the feeding point 15 to each of the two opposing points 16c, 16c in the loop-shaped first antenna element 11 is the length of the short side of the rectangular loop. 1/2 = equal to 30 mm.

The overall size of the antenna body 10 of the multi-frequency antenna 1 of the first embodiment is the total length of the line 16 (element spacing between the second antenna elements 12 and 12 = λ _1.5G / in the longitudinal direction of the line 16. 2 = 102 mm), and the direction orthogonal to the longitudinal direction of the line 16 is defined by the long side length (= 118 mm) of the first antenna element 11 having a rectangular loop shape.

If the antenna elements for three frequencies of 800 MHz, 1.5 GHz, and 2.0 GHz are all constituted by dipole elements, the pair of 1.5 GHz dipole elements (second antenna elements) 12 in FIGS. It is necessary to provide an 800 MHz dipole element on both outer sides of 12.
Therefore, the total length of the line 16 is equal to the distance between the paired 800 MHz dipole elements. The interval is λ _800M / 2 = 178 mm, which is longer than the line 16 of the first embodiment.
The element length of the 800 MHz dipole element is λ _800M / 2 = 178 mm, which is the longest among the plurality of dipole elements.

Therefore, in the case of a multi-frequency shared antenna in which a plurality of antenna elements are all constituted by dipole elements, the size is defined by the element spacing and element length of the 800 MHz dipole element, both of which are λ _800M / 2 = 178 mm. It is. As a result, the multi-frequency antenna is increased in size.

On the other hand, in the multi-frequency shared antenna 1 of the first embodiment, in the case of a multi-frequency shared antenna in which a plurality of antenna elements are all configured by dipole elements, a dipole element for 800 MHz that defines the size thereof is used. Since it was abolished, it was downsized.
That is, as the antenna element 11 for the minimum frequency (here, 800 MHz) that causes an increase in size, the multi-frequency shared antenna 1 of the first embodiment uses a loop antenna instead of a dipole element, and dipole elements 12 and 13. Placed inside.
As a result, the size of the antenna body 10 in the longitudinal direction of the line 16 can be reduced by the absence of the 800 MHz dipole elements that should be located at both ends of the line 16 in the longitudinal direction.

  Also in the antenna 1 of the first embodiment, the size in the direction orthogonal to the longitudinal direction of the line 16 is the first antenna element 11 for 800 MHz, but the length is rectangular. The length of the long side of the first antenna element 11 is 118 mm. This is shorter than the element length of the 800 MHz dipole element = 178 mm, and is miniaturized.

Depending on how the lengths of the short side 11a and the long side 11b of the rectangular first antenna element 11 are set, the size of the antenna 1 according to the first embodiment in the direction orthogonal to the longitudinal direction of the line 16 is set. The element length of the second antenna element 12 for the lowest frequency (here, 1.5 GHz) among the dipole elements 12 and 13 may be defined.
For example, when the length of the long side (side orthogonal to the line 16) of the rectangular first antenna element 11 is set to be smaller than the element length λ _1.5G / 2 = 102 mm of the second antenna element 12 The element length of the second antenna element 12 defines the size in the direction orthogonal to the longitudinal direction of the line 16 in the antenna 1.

Since the loop-shaped first antenna element 11 disposed between the pair of dipole elements 13 is not limited as long as it is in a loop shape, the design freedom is high, which is advantageous.
Moreover, even if the distance between the pair of dipole elements 13 for the highest frequency (here, 2.0 GHz) is narrow, the first antenna element 11 is placed between the pair of dipole elements 13 for the highest frequency. It is possible to arrange in
That is, as the shape of the first antenna element 11, the highest frequency is obtained by making the length in the longitudinal direction of the line 16 relatively small and making the length in the direction orthogonal to the longitudinal direction of the line 16 relatively large. Even if the distance between the pair of dipole elements 13 is narrow, the loop-shaped antenna element 11 can be arranged between the dipole elements 13.

More specifically, the first antenna element 11 has a rectangular shape shown in FIGS. 1 and 2, a short axis substantially coincides with the longitudinal direction of the line 16, and a long axis is orthogonal to the longitudinal direction of the line 16. It can be a shape that substantially matches the direction.
However, when the distance between the pair of antenna elements 13 for the highest frequency (here, 2.0 GHz) is sufficiently wide, the length in the longitudinal direction of the line 16 is relatively large, and the length in the longitudinal direction of the line 16 A shape having a relatively small length in the orthogonal direction can also be used.

Here, in the line 16, a part from the feeding point 15 to the loop-shaped first antenna element 11 is referred to as a first line 16 a, and a part from the first antenna element 11 to the second antenna element 12. Is the second line 16b.
The first line 16 a is a line necessary to reach the first antenna element 11 from the feeding point 15 located on the inner peripheral side of the loop-shaped first antenna element 11.
The entire line 16 is a line necessary for reaching the dipole elements 12 and 13 from the feeding point 15.

In the first embodiment, as the line 16 necessary for reaching the dipole elements 12 and 13 from the feeding point 15, the first line 16a necessary for reaching the loop-shaped first antenna element 11 from the feeding point 15 is used. Has been. Further, the line 16 necessary to reach the dipole elements 12 and 13 from the feeding point 15 is configured by forming a second line 16b obtained by extending the first line 16a to the outer peripheral side of the first antenna element 11. ing.
That is, in the first embodiment, a part of the line 16 necessary to reach the dipole elements 12 and 13 from the feeding point 15 reaches the first antenna element 11 in the loop shape from the feeding point 15. It is also used as one line 16a. As a result, the configuration of the multi-frequency antenna 1 is simplified.

  FIG. 3 shows the multi-frequency shared antenna 1 according to the first comparative example. The difference between the first embodiment and the first comparative example is the shape of the rectangular first antenna element 11. In the first comparative example, the rectangular first antenna element 11 is formed in a square (89 mm × 89 mm). The arrangement and shape of the second antenna element 12 of the first comparative example are the same as in the first embodiment. On the other hand, the pair of third antenna elements 13 and 13 for 2.0 GHz in the first comparative example are located on the inner peripheral side of the first antenna element 11 having a rectangular loop shape. In the first comparative example, the element spacing between the pair of third antenna elements 13 and 13 is 84 mm.

FIG. 4 shows the VSWR characteristics of the multi-frequency shared antenna 1 of the first embodiment, and FIG. 5 shows the horizontal plane directivity of the multi-frequency shared antenna 1 of the first embodiment.
FIG. 6 shows the VSWR characteristics of the multi-frequency shared antenna 1 of the first comparative example, and FIG. 7 shows the horizontal plane directivity of the multi-frequency shared antenna 1 of the first comparative example.

As shown in FIG. 4, in the first embodiment, in each frequency band (800 MHz band, 1.5 GHz band, 2.0 GHz band), the VSWR is in the vicinity of 2.00 or lower, which is good as an antenna. The characteristic is acquired. On the other hand, as shown in FIG. 6, in the first comparative example, the VSWR deteriorates in each frequency band.
Further, as is apparent from the comparison between FIGS. 5 and 7, in the first comparative example, the gain in the 0 degree direction for the third antenna element 13 located inside the loop-shaped first antenna element 11 is the first. Compared to the embodiment.

  That is, when the antenna element 13 is arranged inside the loop-shaped first antenna element 11 as in the first comparative example, the characteristics of the antenna 1 deteriorate, whereas the loop-like shape as in the first embodiment. Good characteristics can be obtained by disposing other antenna elements inside the first antenna element 11 and arranging them only on the outside.

[2. Second Embodiment: Antenna with Parasitic Element]
8 and 9 show the multi-frequency antenna 1 according to the second embodiment. In the antenna 1 of the second embodiment, a parasitic element 41 is disposed between the third antenna element 13 and the reflector 30. As shown in FIG. 9, the parasitic element 41 is formed on the substrate 43. The substrate 43 is supported at a predetermined interval from the reflection plate 30 by a support portion 44 attached to the reflection plate 30. In FIG. 8, the substrate 43 and the support portion 44 are omitted.
In the second embodiment (also the first embodiment), the distance between the antenna body 10 and the reflector 30 is set to 70 mm in consideration of the fact that the first antenna element 11 for 800 MHz is for 800 MHz. (Note that the theoretically appropriate distance is λ _800M / 4 = 89 mm).
Here, since the antenna body 10 is provided on the flat substrate 10a, the distance between the second antenna element 12 and the third antenna element 13 other than the first antenna element 11 and the reflecting plate 30 is also 70 mm. Yes. However, this interval is not very appropriate for the second antenna element 12 and the third antenna element 13.

Therefore, as shown in FIGS. 8 and 9, by placing the parasitic element 41 behind the third antenna element 13, the parasitic element 41 functions as a reflector of the third antenna element 13. Improved characteristics. The distance between the third antenna element 13 and the parasitic element 41 can be set to λ _2.0G / 4, for example.
In the second embodiment, as shown in FIG. 11, it can be seen that the gain in the 0-degree direction of the third antenna element (for 2.0 GHz) 13 having the parasitic element 41 behind is improved.
Further, since the parasitic element 41 can also function as a reflecting plate of the second antenna element (for 1.5 GHz) 12, the VSWR in the 1.5 GHz band is improved as shown in FIG.

  In addition, the point which abbreviate | omitted description in 2nd Embodiment is the same as that of 1st Embodiment.

[3. Third Embodiment: Antenna with Parasitic Element]
12 and 13 show the multi-frequency shared antenna 1 according to the third embodiment. The antenna 1 of the third embodiment includes a parasitic element 42 between the second antenna element 12 and the reflector 30 in addition to the parasitic element 41 between the third antenna element 13 and the reflector 30. It is arranged. The distance between the second antenna element 12 and the parasitic element 42 can be set to λ _1.5G / 4, for example. As shown in FIG. 13, both parasitic elements 41 and 42 are formed on substrates 43a and 43b.

The parasitic element 42 disposed behind the second antenna element 12 functions as a reflector of the second antenna element 12. The first parasitic element 41 is formed on the first substrate 43 a, the second parasitic element 42 is formed on the second substrate 43 b, and the substrates 43 a and 43 b are supported by the support portion 44. It is supported. Also in the third embodiment, it is possible to improve the antenna characteristics compared to the first embodiment.
In the third embodiment, points that are not described are the same as those in the first or second embodiment.

[4. Fourth Embodiment]
FIG. 14 shows a multi-frequency shared antenna 1 according to the fourth embodiment. In the antenna 1 of the first embodiment, the first to third antenna elements 11, 12, and 13 are arranged in the same plane. However, in the fourth embodiment, depending on the frequency of each antenna element 11, 12, and 13 Thus, the distances from the reflecting plate 30 to the antenna elements 11, 12, 13 are different. As a result, good antenna characteristics can be obtained without providing parasitic elements as in the second and third embodiments.
The distance from the reflection plate 30 to the respective antenna elements 11, for example, for the first antenna element 11 lambda _800M / 4, for the second antenna element 12 lambda _1.5G / 4, the third antenna element 13 It is set to λ _2.0G / 4.

[5. Fifth Embodiment]
FIG. 15 shows a multi-frequency shared antenna 1 according to the fifth embodiment. In the fifth embodiment, similarly to the fourth embodiment, the distances from the reflector 30 to the antenna elements 11, 12, and 13 are different according to the frequencies of the antenna elements 11, 12, and 13, respectively. However, as a line extending from the power feeding unit 20 to the second antenna element 12 and the third antenna element 13, the line 17 for the second antenna element 12 and the third antenna element 13 are separated from the line 16 a for the first antenna element. Are provided separately from each other.
The distance from the reflection plate 30 to the respective antenna elements 11, for example, for the first antenna element 11 lambda _800M / 4, for the second antenna element 12 lambda _1.5G / 4, the third antenna element 13 It is set to λ _2.0G / 4.

[6. Sixth Embodiment: Antenna Device Corresponding to Horizontal Polarization and Vertical Polarization]
FIG. 16 shows an antenna device 100 that supports horizontal polarization and vertical polarization. The antenna device 100 is functionally equivalent to a combination of two multi-frequency antennas 1 of the third embodiment. That is, the antenna device 100 includes a vertical polarization obtained by rotating the first multi-frequency antenna 1-1 for horizontal polarization and the first multi-frequency antenna 1-1 for horizontal polarization about the front-rear axis. This is a combination of the second multi-frequency antenna for wave 1-2 and the position in the front-rear direction.

Here, as shown in FIG. 17, when all the three antenna elements 11, 12, and 13 are formed of dipole elements, the antenna body corresponding to the horizontally polarized waves and the vertically polarized waves are overlapped with each other. It can form on the same plane, without producing.
On the other hand, in the multi-frequency antenna 1 according to the embodiment, since the loop antenna element 11 is further located inside the antenna element 13, the loop antenna elements 11 and 11 are adapted to support horizontal polarization and vertical polarization. They overlap each other. They cannot be formed on the same plane. Therefore, as shown in FIG. 16, it is necessary to overlap the horizontally polarized antenna body 10 and the vertically polarized antenna body 10 while shifting them in the front-rear direction (vertical direction in FIG. 16).

  When only two reflector bodies 30 are provided when the two antenna bodies 10 and 10 are shifted in the front-rear direction, one of the two antenna bodies 10 and 10 is spaced from the reflector 30. Becomes inappropriate. Therefore, the antenna device 100 includes two reflectors (first reflector 31 and second reflector 32) corresponding to the antenna body 10 for horizontal polarization and the antenna body 10 for vertical polarization, respectively. Yes.

  Here, FIG. 18 shows only the first multi-frequency shared antenna 1-1 for horizontal polarization extracted from the antenna device 100 of FIG. The antenna 1-1 in FIG. 18 is substantially the same as the antenna 1 according to the second embodiment, except that the first reflector 31 for the first multi-frequency shared antenna 1-1 for horizontal polarization is the same. The slit 31a is formed long in the longitudinal direction (horizontal direction) of the dipole elements 12 and 13. As a result, the first reflecting plate 31 does not reflect vertically polarized waves but reflects horizontally polarized waves.

  As shown in FIGS. 19 and 20, the characteristics of the first multi-frequency antenna 1-1 having the slit 31a formed in the reflector 31 are substantially the same as the characteristics of the antenna 1 according to the third embodiment having no slit. .

  FIG. 21 shows the antenna device 100 shown in FIG. 16 in which only the vertically polarized second multi-frequency shared antenna 1-2 is extracted (however, the power feeding unit 20 is omitted). The vertically polarized second multi-frequency shared antenna 1-2 corresponds to the horizontally polarized first multi-frequency shared antenna 1-1 rotated 90 ° around the front-rear direction axis. Therefore, the second reflecting plate 32 for the second multi-frequency antenna 1-2 for vertical polarization has a slit 32a formed long in the longitudinal direction (vertical direction) of the dipole elements 12 and 13. As a result, the second reflecting plate 32 does not reflect horizontally polarized waves but reflects vertically polarized waves.

Therefore, even if the antenna device 100 includes the two reflectors 31 and 32, when viewed from the two antenna bodies 10, since it is the same situation that only a single reflector exists, the two antennas 100 are provided. The reflector can be positioned at an appropriate position for each of the main bodies 10.
Therefore, like the antenna device 100 of FIG. 16, the first multi-frequency shared antenna 1-1 for horizontal polarization and the first multi-frequency shared antenna 1-1 for horizontal polarization are rotated by 90 ° about the front-rear direction axis. It can be combined with the rotated second polarized wave common antenna 1-2 for vertical polarization and the position in the front-rear direction is shifted.

  In the antenna device 100 of FIG. 16, the members of the vertically polarized antenna 1-2 are arranged so as to be positioned in front of the members of the horizontally polarized antenna 1-1. However, the arrangement may be reversed.

  The power feeding unit 20 is attached to the first reflecting plate 31 and passes through the slit 32 a of the second reflecting plate 32. The feeding unit 20 is connected to the feeding point 15 of the antenna body 10 for horizontally polarized waves, and further extends to the feeding point 15 of the antenna body 10 for vertically polarized waves.

[7. Seventh Embodiment: Antenna Device Corresponding to Horizontal Polarization and Vertical Polarization]
FIG. 22 shows an antenna device 100 according to the seventh embodiment. As in the sixth embodiment, the antenna device 100 according to the present embodiment is a second vertically polarized second antenna obtained by rotating the horizontally polarized first multi-frequency shared antenna 1-1 by 90 ° around the longitudinal axis. The frequency sharing antenna 1-2 is combined with the position in the front-rear direction.

  Here, in the antenna device 100 according to the sixth embodiment, when a current flows through the loop antenna element 11 of the first multi-frequency shared antenna 1-1 disposed on the rear side, a magnetic field is generated by the current flow, An induced current flows through the loop antenna element 11 of the second multi-frequency shared antenna 1-2 arranged on the front side. When this induced current flows, a magnetic field is generated by the flow, and the induced current also flows through the loop antenna element 11 of the first multi-frequency common antenna 1-1. As described above, in the antenna device 100 according to the sixth embodiment, the induced currents interfere with each other, and the antenna characteristics are deteriorated as compared with the case where each of the antennas 1-1 and 1-2 is used alone. To do.

  Therefore, in order to suppress the flow of the induced current, the antenna device 100 of the present embodiment has the loop antenna elements (the first multi-frequency antenna 1-1 and the second multi-frequency common antenna 1-2) (first antenna). The antenna element 11 includes a first cutting unit 11-1 and a second cutting unit 11-2 that are electrically cut at two points along the loop.

  The 1st cutting part 11-1 and the 2nd cutting part 11-2 consist of the clearance gap formed by cut | disconnecting a part of each loop antenna element 11. FIG. The gap is preferably long enough to prevent a short circuit and not to adversely affect the antenna characteristics by changing the circumference of the loop (one wavelength in this embodiment). In this embodiment, the gap is set to 2 to 3 mm.

  FIG. 23 shows an antenna device 100 of FIG. 22 in which only the first multi-frequency shared antenna 1-1 for horizontal polarization is extracted. The antenna main body 10 in the antenna 1-1 of FIG. 23 includes a line 16-1 connected to the antenna elements 11, 12, and 13 from the feeding point 15 as in the first embodiment. The line 16-1 includes a pair of line elements 16-1a and 16-1b that extend linearly in opposite directions (different directions) from the feeding point 15 and are connected to the antenna elements 11, 12, and 13, respectively. ing. Both line elements 16-1a and 16-1b are formed to have the same length, and the length is ½ (= 102/2 = 51 mm) of the entire length of the line 16-1.

Both line elements 16-1a and 16-1b are connected to different locations in the loop antenna element 11. The path length L1 from the connection point 51 between the line element 16-1a and the loop antenna element 11 to the first cutting portion 11-1, and the first cut from the connection point 52 between the line element 16-1b and the loop antenna element 11. The path length L2 to the section 11-1 is set to be substantially the same length. The path lengths L1 and L2 are ½ length (= 118/2 = 59 mm) of the long side 11b of the loop antenna element 11 and ½ length (= 60/2 = 30 mm) of the short side 11a. ), That is, about 1/4 of the wavelength (λ _800M ) of ₈₀₀ MHz (= λ _800M / 4 = 89 mm).

  FIG. 24 shows an antenna device 100 of FIG. 22 in which only the second multi-frequency shared antenna 1-2 for vertical polarization is extracted. The antenna main body 10 in the antenna 1-2 of FIG. 24 includes a line 16-2 connected to the antenna elements 11, 12, and 13 from the feeding point 15 as in the first embodiment. The line 16-2 has the same configuration as the line 16-1 described above, extends linearly in opposite directions (different directions) from the feeding point 15, and is connected to the antenna elements 11, 12, and 13. A pair of line elements 16-2a and 16-2b. Both line elements 16-2a and 16-2b are formed to have the same length, and the length is ½ (= 102/2 = 51 mm) of the entire length of the line 16-2.

Both line elements 16-2a and 16-2b are connected to different locations in the loop antenna element 11. The path length L3 from the connection point 53 between the line element 16-2a and the loop antenna element 11 to the second cutting part 11-2 and the second cut from the connection point 54 between the line element 16-2b and the loop antenna element 11 The path length L4 to the section 11-2 is set to be substantially the same length. The path lengths L3 and L4 are ½ of the long side 11b of the loop antenna element 11 (= 118/2 = 59 mm) and ½ of the short side 11a (= 60/2 = 30 mm), that is, about 1/4 of the wavelength of 800 MHz (λ _800M ) (= λ _800M / 4 = 89 mm).

Note that the first cutting portion 11-1 and the second cutting portion 11-2 in FIGS. 23 and 24 are formed by gaps formed by cutting a part of the loop antenna element 11. An insulating material to be cut may be interposed.
Further, the path lengths L1 and L2, L3 and L4 are set to the same length, respectively, but are equivalent to the case where the first cutting part 11-1 and the second cutting part 11-2 are not provided. Different lengths may be set as long as antenna characteristics can be realized.

FIG. 25A shows the reflection characteristics of the first multi-frequency antenna 1-1 for horizontal polarization according to the present embodiment, and FIG. 25B shows the first for horizontal polarization according to the sixth embodiment. This is a reflection characteristic of the multi-frequency shared antenna 1-1. FIG. 26A shows the reflection characteristics of the vertically polarized second multi-frequency shared antenna 1-2 of this embodiment, and FIG. 26B shows the vertically polarized wave of the sixth embodiment. This is a reflection characteristic of the second multi-frequency shared antenna 1-2.
When (a) and (b) in FIG. 25 and (a) and (b) in FIG. 26 are respectively compared, the reflection characteristic of the present embodiment is higher than the reflection characteristic of the sixth embodiment (the center of the pie chart). ) And the reflection characteristics are improved. That is, it can be seen that the induction current that causes the deterioration of the reflection characteristics is suppressed from flowing to the antennas 1-1 and 1-2.

  FIG. 27 shows the horizontal plane directivity of the first multi-frequency shared antenna 1-1 for horizontal polarization according to this embodiment. When comparing the horizontal plane directivity of the antenna 1-1 of the sixth embodiment shown in FIG. 27 and FIG. 20, the gain in the 0 degree direction of the antenna 1-1 of the present embodiment is the same as that of the antenna 1-1 of the sixth embodiment. It is almost the same as the gain in the 0 degree direction, and the antenna 1-1 of the present embodiment having the first cutting part 11-1 realizes the same antenna characteristics as the case where the first cutting part 11-1 is not provided. I understand that.

  FIG. 28A shows the vertical directivity of the first multi-frequency antenna 1-1 for horizontal polarization according to this embodiment, and FIG. 28B shows the first for horizontal polarization according to the sixth embodiment. This is the vertical plane directivity of the multi-frequency antenna 1-1. When comparing (a) and (b) of FIG. 28, the gain in the 0 degree direction of the antenna 1-1 of the present embodiment is substantially the same as the gain in the 0 degree direction of the antenna 1-1 of the sixth embodiment. It can be seen that the antenna 1-1 of the present embodiment having the first cutting part 11-1 achieves the same antenna characteristics as the case where the first cutting part 11-1 is not provided.

  FIG. 29A is a horizontal plane directivity of the second multi-frequency antenna for vertical polarization 1-2 according to the present embodiment, and FIG. 29B is a second multi-polarization for vertical polarization according to the sixth embodiment. This is the horizontal plane directivity of the frequency sharing antenna 1-2. FIG. 30 (a) shows the vertical plane directivity of the second multi-frequency antenna for vertical polarization 1-2 of this embodiment, and FIG. 30 (b) shows the vertical polarization for the sixth embodiment. This is the vertical plane directivity of the second multi-frequency shared antenna 1-2. When comparing (a) and (b) of FIG. 29 and (a) and (b) of FIG. 30 respectively, the gain in the 0-degree direction of the antenna 1-2 of the present embodiment is the antenna 1 of the sixth embodiment. 2 is substantially the same as the gain in the 0-degree direction, and the antenna 1-2 of the present embodiment having the second cutting section 11-2 achieves the same antenna characteristics as when the second cutting section 11-2 is not provided. You can see that

  As described above, according to the antenna device 100 of the present embodiment, a current is supplied to one loop antenna element 11 among the loop antenna elements 11 of the first multi-frequency shared antenna 1-1 and the second multi-frequency shared antenna 1-2. When the current flows, the first and second cutting portions 11-1 and 11-2 can suppress the induction current from flowing to the other loop antenna element 11 due to the current flow. Thereby, it can suppress that the 1st multi-frequency common antenna 1-1 and the 2nd multi-frequency common antenna 1-2 interfere with each other by the said induced current.

  The first cutting section 11-1 has a path length L1 from the feeding point 15 through the one line element 16-1a to the first cutting section 11-1, and the other line element 16 from the feeding point 15. Since the path length L2 passing through -1b and reaching the first cutting section 11-1 is substantially the same length, that is, the position where current does not flow originally, the first multi-frequency shared antenna 1-1 is Even if it has the 1st cutting part 11-1, the antenna characteristic equivalent to the case where it does not have the 1st cutting part 11-1 is realizable.

  Further, the second cutting section 11-2 has a path length L3 from the feeding point 15 through the one line element 16-2a to the second cutting section 11-2, and the other line element 16 from the feeding point 15 to the other line element 16. -2b and the path length L4 leading to the second cutting part 11-2 is at a position where it is substantially the same length, that is, a position where current does not flow originally, the second multi-frequency shared antenna 1-2 is Even if it has the 2nd cutting part 11-2, the antenna characteristic equivalent to the case where it does not have the 2nd cutting part 11-2 is realizable.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
For example, a plurality of antenna elements formed in a loop shape may be provided. That is, as shown in FIG. 31, in addition to the first antenna element 11 that resonates at the lowest frequency, the second antenna element 12 that resonates at the second lowest frequency is also formed in a loop shape, and the remaining second The three antenna elements 13 may be dipole elements.
Furthermore, as a modification thereof, a part of the first antenna element 11 may be used as a part of the second antenna element 12 as shown in FIG. In this case, the loop of the second antenna element 12 includes the first side element 12a, the second side element 12b, the third side element 12c, the fourth side element 12d1, the fifth side element 12d2, the sixth side element 12e, and the seventh side element. The side element 12f, the eighth side element 12g, the ninth side element 12h1, and the tenth side element 12h2 are formed. Among the first to tenth side elements 12a to 12h2, the second side element 12b, the fourth side element 12d1, the fifth side element 12d2, the seventh side element 12f, the ninth side element 12h1, and the tenth side element 12h2 are: It is a part of the first loop element 11 and is also used as a part of the second loop element 12.

1 Multi-frequency antenna element 10 Antenna body 11 First antenna element (loop-shaped antenna element)
12 Second antenna element (dipole element)
13 Third antenna element (dipole element)
DESCRIPTION OF SYMBOLS 15 Feed point 16 Line 16a 1st line 16b 2nd line 20 Feed part 30 Reflector 31 First reflector 32 Second reflector 41 Parasitic element 42 Parasitic element 100 Antenna apparatus 1-1 1st multifrequency antenna 1 -2 2nd multifrequency antenna 11-1 1st cutting part 11-2 2nd cutting part 16-1a Line element 16-1b Line element 16-2a Line element 16-2b Line element 51-54 Connection point

Claims (7)

A multi-frequency antenna having a plurality of antenna elements that resonate at different frequencies,
As the plurality of antenna elements, including a dipole element and a loop-shaped antenna element,
The loop-shaped antenna element is an antenna element that resonates at least at the lowest frequency among the plurality of antenna elements,
The multi-frequency shared antenna, wherein the dipole element is disposed on an outer peripheral side of the loop-shaped antenna element and is not disposed on an inner peripheral side of the loop-shaped antenna element. A line extending from a feeding point is provided and connected to each of the plurality of antenna elements, and the line is connected to the looped antenna element from a feeding point provided on the inner peripheral side of the looped antenna. The multi-frequency common use according to claim 1, further comprising: a first line that extends to the dipole element by extending the first line to an outer peripheral side of the loop-shaped antenna element. antenna. The multi-frequency shared antenna according to claim 2, wherein the dipole element, the loop-shaped antenna element, and the line are formed on the same substrate. A reflector provided behind the plurality of antenna elements;
A parasitic element disposed between the reflector and the dipole element;
The multi-frequency antenna according to any one of claims 1 to 3, further comprising: A first multi-frequency antenna for horizontal polarization using the multi-frequency antenna according to claim 1;
A second multi-frequency common antenna for vertical polarization using the multi-frequency common antenna according to claim 1;
With
The first multi-frequency shared antenna includes a first reflector formed so as not to reflect vertically polarized waves but to reflect horizontally polarized waves,
The second multi-frequency shared antenna includes a second reflector formed so as not to reflect horizontally polarized waves but to reflect vertically polarized waves,
The antenna device characterized in that the first multi-frequency shared antenna and the second multi-frequency shared antenna are arranged so as to overlap each other by changing the positions of the first reflector and the second reflector in the front-rear direction. . The loop-shaped antenna element of the first multi-frequency common antenna has a first cut portion that is electrically cut in the middle of the loop,
The antenna device according to claim 5, wherein the loop-shaped antenna element of the second multi-frequency shared antenna has a second cut portion that is electrically cut in the middle of the loop. The first multi-frequency shared antenna includes a pair of line elements that extend in different directions from the feeding point and have the same length as each other, and are connected to different positions in the loop-shaped antenna element,
The second multi-frequency shared antenna includes a pair of line elements that extend in different directions from the feeding point and have the same length as each other, and are connected to different positions in the loop-shaped antenna element,
Of the pair of line elements of the first multi-frequency antenna, the path length from the connection point between one line element and the loop-shaped antenna element to the first cut portion, the other line element and the loop-shaped element The path length from the connection point with the antenna element to the first cut portion is set to be substantially the same length,
Of the pair of line elements of the second multi-frequency antenna, the path length from the connection point between one line element and the loop-shaped antenna element to the second cut portion, the other line element and the loop-shaped element The antenna device according to claim 6, wherein a path length from a connection point with the antenna element to the second cut portion is set to be substantially the same length.

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