JP2016123042A - Collinear antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain good VSWR characteristics over a wide band by a simple feeding system similar to series feeding, while enhancing the gain by suppressing side lobe, and to deal with change of operation frequency easily.SOLUTION: Dielectric substrates 1a-1d are installed, respectively, on respective surfaces of a substrate 3 consisting of a conductive hollow cylinder having four surfaces directing different directions. Furthermore, CRLH lines 2a-2d are arranged on the surfaces of these dielectric substrates 1a-1d perpendicularly thereto. Feeding parts are provided at the proximal ends of the CRLH lines 2a-2d, respectively, and the same power is supplied thereto. Matching termination resistors are provided, respectively, at the ends of the CRLH lines 2a-2d.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a collinear antenna used for a base station of a mobile communication system, for example.

  In mobile communication systems such as mobile phone systems and PHS (Personal Handyphone System), for example, collinear antennas are used as communication antennas (see, for example, Patent Document 1). There are two types of feeding methods for the collinear antenna: a series feeding method and a parallel feeding method. In the series power feeding method, a band where a good voltage standing wave ratio (VSWR) characteristic is obtained is generally narrow. On the other hand, in the parallel feeding method, since each radiating element has a configuration close to a dipole antenna, even if power is supplied as a collinear array by using an antenna having a relatively wide band, in principle, a good VSWR is achieved over a wide band. It becomes possible to maintain the characteristics.

JP2011-89919A

  However, the radome diameter of a collinear antenna is generally limited. For this reason, when the number of antennas is increased, the feeding cable bundled for parallel feeding approaches the radiating element and degrades the characteristics of the radiating element. As a result, the collinear antenna as a whole degrades the VSWR characteristics and directivity. Therefore, the use of the parallel power feeding method does not always provide good VSWR characteristics.

  Regardless of whether the feeding method is serial or parallel, the conventional collinear antenna has a limited arrangement of radiating elements (for example, 0.5 to 0.95λ), so the arrangement of distributors and matching circuits is limited. It is done. Generally, a radiating element is comprised by the element of 0.35-0.5 (lambda). In order to obtain stable excitation, an unintended conductor cannot be disposed in the vicinity of the radiating element. For this reason, the lower limit of the interval between the radiating elements is about 0.5λ.

  Further, when arraying antennas, it is necessary to prevent grating lobes. A grating lobe is generated when the distance between the radiating elements is 1.0λ or more, and when a grating glove is generated, the gain is greatly reduced. Even if the interval is shorter than this, the side lobe tends to be large and the gain tends to decrease due to the influence of the radiating element and the distributor. Therefore, the upper limit of the distance between the radiating elements is about 0.95λ. However, when the maximum size of the antenna is constant and the number of stages of the radiating elements is changed, in parallel feeding, the distribution number, arrangement, and dimensions of the distributors must be taken into consideration. In the series power feeding method, the phase shift circuit must be changed when the interval between the radiating elements changes. However, the distributor and the phase shift circuit must be arranged in a limited space between the radiating elements and cannot be easily changed.

  The present invention has been made paying attention to the above circumstances, and the object of the present invention is to obtain a good VSWR characteristic over a wide band by a simple power feeding method similar to that of series power feeding and to suppress side lobes. It is an object of the present invention to provide a collinear antenna that can improve the gain and can easily cope with a change in operating frequency.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a dielectric substrate in which a ground plane is disposed on a first surface and a second surface on the back side of the first surface is open. A radiating element comprising a right / left-handed composite transmission line is arranged vertically on the second surface of the dielectric substrate, and a power feeding part is provided at the first end of the radiating element, and power is supplied to the power feeding part. , And a matching termination circuit is provided at the second end of the radiating element.

  According to a second aspect of the present invention, there is provided a base made of a hollow cylinder having a plurality of surfaces facing different directions on the surface side using a conductive material, and a plurality of dielectric substrates respectively disposed on the plurality of surfaces of the base A plurality of radiating elements composed of a right / left-handed composite transmission line in a vertical direction so as to be parallel to the surfaces of the plurality of dielectric substrates, and a first end of the plurality of radiating elements Each of the power supply sections is provided with the same power, and a matching termination circuit is provided at each of the second ends of the plurality of radiating elements.

  According to a third aspect of the present invention, there is provided a dielectric substrate in which a ground plane is disposed on the first surface and a second surface on the back side of the first surface is open. A plurality of radiating elements composed of a right / left-handed composite transmission line are arranged on the second surface so that each is arranged in a vertical direction, and a feeding portion is provided at a first end of the plurality of radiating elements facing each other. The power supply portions are supplied with powers having phases different from each other by 180 °, and the matching termination circuits are provided at the second ends of the plurality of radiating elements that are separated from each other.

  According to the first aspect of the present invention, since the right-hand / left-handed composite transmission line operates as a traveling wave antenna, it is possible to provide a horizontal directional antenna having a good VSWR characteristic over a wide band. In addition, the right / left-handed composite transmission line has a configuration in which a plurality of units each constituting a lumped constant line are densely arranged in series, and each unit also serves as a radiating element, a divider, and a phase circuit. Generation of side lobes can be kept low, thereby improving the gain. Furthermore, the operating frequency can be easily changed without changing the radiating element length by simply changing the lumped constant arranged in each unit. In addition, the beam tilt can be adjusted in an appropriate direction by changing the balance frequency by changing the lumped constant arranged in each unit.

  According to the 2nd viewpoint of this invention, in addition to the effect described in the 1st viewpoint, there exist the following effects. That is, since a plurality of radiating elements each composed of a right-hand / left-handed composite transmission line are arranged so as to face in different directions, the radiation in the horizontal direction can be made uniform even when the antenna diameter is large. A collinear antenna having horizontal omnidirectionality can be provided by appropriately selecting the number and orientation of the antennas. In addition, since the radiating element is arranged on the peripheral surface of the cylindrical base body, it is possible to accommodate the feed line in the cylinder of the base body, and the base body is made of a conductive material. The mutual influence between can be greatly reduced.

  According to the 3rd viewpoint of this invention, in addition to the effect described in the 1st viewpoint, there exist the following effects. That is, a plurality of radiating elements composed of a right / left-handed composite transmission line are arranged side by side in the vertical direction with the feeding points facing each other, and are fed so that the phases differ from each feeding point by 180 °. In this way, the beam tilt can be adjusted to a predetermined value, for example, 0 °, even when the beam tilt cannot be adjusted by adjusting the balance frequency by changing the lumped constant arranged in each unit.

  That is, according to the present invention, it is possible to obtain a good VSWR characteristic over a wide band by a simple power feeding method similar to that of series power feeding, to suppress side lobes and improve gain, and to change the operating frequency. It is possible to provide a collinear antenna that can easily cope with this.

The perspective view which shows the structure of the collinear antenna which concerns on 1st Embodiment of this invention. The AA arrow sectional drawing of the collinear antenna shown in FIG. The figure which expanded and showed a part of collinear antenna shown in FIG. The figure which shows an example of the horizontal surface directivity obtained with the collinear antenna shown in FIG. The figure which shows an example of the vertical surface directivity obtained by the collinear antenna shown in FIG. The perspective view which shows the structure of the collinear antenna which concerns on 2nd Embodiment of this invention. CC arrow sectional drawing of the collinear antenna shown in FIG. The perspective view which shows the structure of the collinear antenna which concerns on 3rd Embodiment of this invention. BB arrow sectional drawing of the collinear antenna shown in FIG. The figure which expanded and showed a part of collinear antenna shown in FIG. The figure which shows an example of the horizontal surface directivity obtained with the collinear antenna shown in FIG. The figure which shows an example of the vertical surface directivity obtained by the collinear antenna shown in FIG. The perspective view which shows the structure of the collinear antenna which concerns on 4th Embodiment of this invention. The figure which shows an example of the horizontal surface directivity obtained with the collinear antenna shown in FIG. The figure which shows an example of the vertical surface directivity obtained with the collinear antenna shown in FIG.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
1 is a perspective view showing a configuration of a collinear antenna according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of the collinear antenna shown in FIG. 1 taken along the line AA, and FIG. 3 is a part of FIG. It is the top view expanded and shown.

  In FIG. 1, reference numeral 1 denotes a dielectric substrate, and the dielectric substrate 1 is constituted by, for example, a printed wiring board (printed board) formed in a strip shape. A ground pattern is formed on the entire back surface of the dielectric substrate 1, and a pattern constituting the radiating element 2 is formed on the front surface using, for example, a microstrip line.

  The radiating element 2 includes a right / left-handed composite transmission line (CRLH line). In the following description, the CRLH line is also denoted by the same reference numeral as that of the radiating element. The CRLH line 2 is formed by connecting a plurality of units each constituting a lumped constant line in series in the longitudinal direction. One unit is loaded with capacitance elements 22, 22,... Between one conductive part 20 and conductive parts 21, 21 arranged at both ends thereof, and further, inductance elements 23, 23 are provided on the conductive part 20. , ... are connected.

  The inductance elements 23, 23,... Have one end connected to the conductive portion 20 and the other end connected to the ground terminal 26. As shown in FIG. 2, the ground terminal 26 is connected to the ground pattern 11 formed on the back surface of the dielectric substrate 1 through the through hole 12. One unit length is set to λ / 10, for example, when the operating frequency is λ. The radiating element length is set to 2.5λ, for example.

  In addition, a power supply conductive portion 27 is disposed at one end of the CRLH line 2, and a power supply point 24 is provided in the power supply conductive portion 27. The feed point 24 is connected to a feed cable (not shown) that forms a feed line. Further, a termination resistor 25 is connected to the end of the CRLH line 2. This termination resistor 25 terminates the termination of the CRLH line 2 with matching.

  The collinear antenna configured as described above is installed vertically with the feeding point 24 as the lower side. In this state, the collinear antenna operates as follows. That is, in each unit of the CRLH line 2, currents having the same phase and the same amplitude are generated, whereby the CRLH line 2 operates as a traveling wave antenna. As a result, a horizontal plane directivity as shown in FIG. 4 is formed in the front direction of the collinear antenna, and a beam tilt is formed in the horizontal direction as shown in FIG. 5, for example. That is, according to the first embodiment, it is possible to provide a directional antenna that has directivity in any one direction in the horizontal direction and has good VSWR characteristics over a wide band.

  The CRLH line 2 has a configuration in which a plurality of units each constituting a lumped constant line are densely arranged in series, and each unit also serves as a radiating element, a distributor, and a phase circuit. For this reason, as shown in FIGS. 4 and 5, the occurrence of side lobes in the horizontal plane and the vertical plane is both kept low, and this makes it possible to increase the antenna gain.

  Further, for example, when a change in operating frequency is requested by a communication carrier, it is possible to change the lumped constant of each unit of the CRLH line 2, that is, the values of the capacitance element 22 and the inductance element 23 without changing the radiating element length. It becomes possible to easily change the operating frequency. Further, if the balance frequency is changed by changing the lumped constant arranged in each unit, the beam tilt can be adjusted in an appropriate direction.

[Second Embodiment]
6 is a perspective view showing a configuration of a collinear antenna according to a second embodiment of the present invention, and FIG. 7 is a cross-sectional view taken along the line CC in FIG. 6 and 7, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals for description.

  The collinear antenna according to the second embodiment includes a single dielectric substrate 10 having a strip shape. The dielectric substrate 10 is composed of, for example, a printed wiring board (printed board). The dielectric substrate 10 has a first surface divided into left and right regions with the longitudinal direction as a boundary, a ground pattern 11a is formed on the entire surface of one region, and a radiating element 2a is formed on the other region. . The second surface of the dielectric substrate 10 is also divided into left and right regions with the longitudinal direction as a boundary. A ground pattern 11b is formed on the entire surface of the region behind the region where the radiating element 2a is formed. A radiating element 2b is formed in a region on the back side of the region where the ground pattern 11a is formed.

  The radiating elements 2a and 2b are configured by a right / left-handed composite transmission line (CRLH line). In the following description, the CRLH line is also denoted by the same reference numeral as that of the radiating element. As in the first embodiment, the CRLH lines 2a and 2b are configured by connecting a plurality of units each constituting a lumped constant line in series in the longitudinal direction. One unit is loaded with capacitance elements 22, 22,... Between one conductive part 20 and conductive parts 21, 21 arranged at both ends thereof, and further, inductance elements 23, 23 are provided on the conductive part 20. , ... are connected.

  The inductance elements 23, 23,... Have one end connected to the conductive portion 20 and the other end connected to the ground terminal 26. The ground terminal 26 is connected to the ground patterns 11 a and 11 b formed on the back surface of the dielectric substrate 10 through the through hole 12. For example, as shown in FIG. 12, the ground terminal 26 of the CRLH line 2a is connected to the ground pattern 11b formed on the back surface of the dielectric substrate 10 through the through hole 12, and the ground terminal 26 of the CRLH line 2b. Is connected to the ground pattern 11 a formed on the back surface of the dielectric substrate 10 through the through hole 12. One unit length is set to λ / 10, for example, when the operating frequency is λ. The radiating element length is set to 2.5λ, for example.

  In addition, a power feeding conductive portion 27 is disposed at one end of each of the CRLH lines 2 a and 2 b, and a power feeding point 24 is provided in the power feeding conductive portion 27. The feeding points 24 of the CRLH lines 2a and 2b are respectively connected to feeding cables (not shown) constituting the feeding lines, and the same power is supplied through the feeding cables. Further, termination resistors 25 are connected to the terminations of the CRLH lines 2a and 2b, respectively. This termination resistor 25 terminates the termination of the CRLH lines 2a and 2b.

  The collinear antenna configured in this way is installed vertically with the feeding point 24 of each CRLH line 2a, 2b facing downward. In this state, the collinear antenna operates as follows. That is, in each unit of the CRLH lines 2a and 2b, currents having the same phase and the same amplitude are generated, so that the CRLH lines 2a and 2b operate as traveling wave antennas. As a result, horizontal plane directivity is formed in the front direction of each CRLH line 2a, 2b, and a beam tilt is formed in the horizontal direction. That is, according to the second embodiment, it is possible to provide a directional antenna that has directivity in two opposite directions in the horizontal direction and has good VSWR characteristics over a wide band.

  Similarly to the first embodiment, each of the CRLH lines 2a and 2b has a configuration in which a plurality of units each constituting a lumped constant line are densely arranged in series, and each unit includes a radiating element and a distributor. Also serves as a phase circuit. For this reason, the occurrence of side lobes in the horizontal plane and the vertical plane is both kept low, thereby providing a high gain antenna.

  Further, for example, when a change in operating frequency is requested from a communication carrier, the radiating element length can be increased by simply changing the lumped constant of each unit of the CRLH lines 2a and 2b, that is, the values of the capacitance element 22 and the inductance element 23. It is possible to easily change the operating frequency without changing it. Further, if the balance frequency is changed by changing the lumped constant of each unit, the beam tilt can be adjusted in an appropriate direction.

[Third Embodiment]
8 is a perspective view showing a configuration of a collinear antenna according to a third embodiment of the present invention, FIG. 9 is a cross-sectional view taken along line BB in FIG. 8, and FIG. 10 is an enlarged view of a part of FIG. It is a top view. 8 to 10, the same parts as those in FIGS. 1 to 3 are denoted by the same reference numerals for description.

  The collinear antenna according to the third embodiment includes a cylindrical base 3 having a square cross section. The substrate 3 is made of a conductive material such as metal. Dielectric substrates 1a to 1d are installed on the four peripheral surfaces of the base 3, respectively. The dielectric substrates 1a to 1d are configured by, for example, a printed wiring board (printed board) formed in a strip shape. Patterns constituting the radiating elements 2a to 2d are formed on the surfaces of the dielectric substrates 1a to 1d using, for example, microstrip lines.

  Each of the radiating elements 2a to 2d is configured by a right-hand / left-handed composite transmission line (CRLH line). In the following description, the CRLH line is also denoted by the same reference numeral as that of the radiating element. As in the first and second embodiments, the CRLH lines 2a to 2d are formed by connecting a plurality of units each constituting a lumped constant line in series in the longitudinal direction. One unit is loaded with capacitance elements 22, 22,... Between one conductive part 20 and conductive parts 21, 21 arranged at both ends thereof, and further, inductance elements 23, 23 are provided on the conductive part 20. , ... are connected.

  The inductance elements 23, 23,... Have one end connected to the conductive portion 20 and the other end connected to the ground terminal 26. As shown in FIG. 9, the grounding terminal 26 is connected to the base 3 through the through hole 12 provided in the dielectric substrates 1 a to 1 d. At this time, the substrate 3 functions as a ground plate.

  Note that one unit length of the CRLH lines 2a to 2d is set to λ / 10, for example, when the operating frequency is λ. Further, the length of the radiating element is set to 2.5λ, for example, and the length of one side of the base 3 including the thicknesses of the dielectric substrates 1a to 1d is set to 0.55λ, for example, as shown in FIG.

  In addition, a power feeding conductive portion 27 is disposed at one end of each of the CRLH lines 2 a to 2 d, and a power feeding point 24 is provided in the power feeding conductive portion 27. A feed cable (not shown) constituting a feed line is connected to the feed point 24, and the same power is supplied through the feed cable. Further, termination resistors 25 are connected to the terminations of the CRLH lines 2a to 2d, respectively. This termination resistor 25 terminates the termination of the CRLH lines 2a to 2d.

  The collinear antenna configured as described above is installed vertically with the feeding point 24 of the CRLH lines 2a to 2d downward. The power feeding cable is guided from a wireless circuit unit (not shown) through the cylinder of the base 3 to the arrangement position of the CRLH lines 2a to 2d, and through a through hole (not shown) provided in the base 3 at the position. Connected to the feeding point 24. In this case, through holes may also be provided in the dielectric substrates 1a to 1d so that the power supply cable can be passed therethrough. However, the dielectric substrates 1a to 1d are connected to the back surfaces of the dielectric substrates 1a to 1d through the through holes. A power feeding terminal may be provided, and a power feeding cable may be connected to the power feeding terminal.

  In such a state, the collinear antenna operates as follows. In other words, in the CRLH lines 2a to 2d, currents having the same phase and the same amplitude are generated in the respective units, whereby the CRLH lines 2a to 2d operate as traveling wave antennas. As a result, horizontal plane directivity as shown in FIG. 11 is formed in the entire circumference direction of the antenna, and beam tilt is formed in the horizontal direction as shown in FIG. 12, for example. That is, according to the third embodiment, it is possible to provide a horizontal omnidirectional antenna having a substantially uniform directivity over the entire circumference in the horizontal direction and having a good VSWR characteristic over a wide band even if the antenna diameter is large. it can.

  Each of the CRLH lines 2a to 2d has a configuration in which a plurality of units constituting a lumped constant line are densely arranged in series, and each unit also serves as a radiating element, a distributor, and a phase circuit. For this reason, as shown in FIGS. 11 and 12, the occurrence of side lobes in the horizontal plane and the vertical plane can be suppressed to a low level, thereby providing a high-gain collinear antenna.

  Further, for example, when a change in operating frequency is requested from a communication carrier, the radiating element length can be increased by simply changing the lumped constant of each unit of the CRLH lines 2a to 2d, that is, the values of the capacitance element 22 and the inductance element 23. It is possible to easily change the operating frequency without changing it. Further, if the balance frequency is changed by changing the concentration constant of each unit, the beam tilt can be adjusted in an appropriate direction.

[Fourth Embodiment]
FIG. 13 is a perspective view showing the configuration of a collinear antenna according to the fourth embodiment of the present invention. In FIG. 13, the same parts as those in FIG.

  In the collinear antenna according to the fourth embodiment, the base substrate 30 and the dielectric substrates 10a to 10d installed on the four surfaces thereof are extended in the longitudinal direction, and the CRLH lines 2a to 2d and the CRLH are connected to the dielectric substrates 10a to 10d. The lines 4a to 4d are arranged in a straight line. Although the CRLH lines 2a to 2d and the CRLH lines 4a to 4d have the same configuration, the arrangement direction is set so that the feeding points 24 face each other and the termination resistors 25 are separated from each other. That is, the CRLH lines 2a to 2d and the CRLH lines 4a to 4d are arranged in a vertically inverted state with the base body 30 installed vertically.

  The CRLH lines 2a to 2d and the CRLH lines 4a to 4d are supplied with electric power whose phases are different from each other by 180 °. The phase difference of 180 ° can be obtained by supplying two systems of power generated by a radio circuit unit (not shown) with a phase difference of 180 ° via a separate power supply cable, or by supplying a single power supply cable from the radio circuit unit. Can be supplied by branching the power supplied via the distributor into two by a distributor and shifting one of them by 180 ° with a phase shifter.

  When the collinear antenna configured as described above is vertically installed and operated, both the CRLH lines 2a to 2d and the CRLH lines 4a to 4d operate as traveling wave antennas. As a result, horizontal plane directivity as shown in FIG. 14 is formed in the entire circumference of the antenna, and a beam tilt is formed in the horizontal direction as shown in FIG. 15, for example. At that time, since the CRLH lines 2a to 2d and the CRLH lines 4a to 4d are arranged in an inverted state and are driven by electric power that is 180 degrees out of phase, the tilt beam tilts in the combined directivity. The angle is set to 0 ° as shown in FIG. That is, even when the beam tilt cannot be adjusted by adjusting the balance frequency by changing the lumped constant arranged in each unit, the beam tilt can be adjusted to a predetermined value, for example, 0 °.

  In addition, it is possible to provide a horizontal omnidirectional antenna that has excellent VSWR characteristics over a wide band and has few side lobes, and only changes the lumped constant of each unit of the CRLH lines 2a to 2d and CRLH lines 4a to 4d. The point that the operating frequency can be changed without changing the radiating element length is the same as that of the third embodiment.

[Other Embodiments]
In the third embodiment, the case where only one set of CRLH lines 2a to 2d is provided has been described as an example. However, a plurality of sets of CRLH lines 2a to 2d may be arranged in multiple stages in the vertical direction. In this case, power feeding to the plurality of sets of CRLH lines 2 a to 2 d is performed by a series power feeding method, and the power feeding cable is wired in the base 3.

  In the third and fourth embodiments, the base 3 is a cylinder having a square cross-sectional shape, and the CRLH lines 2a to 2d are arranged on the four surfaces thereof. The cross sectional shape may be an equilateral triangle or pentagon or more, and three or five or more CRLH lines may be installed on the peripheral surface.

In addition, the material of the base and the dielectric substrate, the configuration of the CRLH line, and the like can be variously modified without departing from the gist of the present invention.
In short, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in each embodiment. Furthermore, you may combine suitably the component covering different embodiment.

  1, 1a to 1d, 10, 10a to 10d, ... dielectric substrate, 2, 2a to 2d, 4a to 4d ... right / left-handed composite transmission line (CRLH line), 3, 30 ... base, 11, 11a, 11b ... Ground pattern, 12 ... Through hole, 20, 21, 40, 41 ... Conductive part, 22, 42 ... Capacitance element, 23, 43 ... Inductance element, 24, 44 ... Feed point, 25 ... Termination resistor, 26, 46 ... Grounding terminals 27, 47...

Claims (3)

A dielectric substrate in which a ground plane is disposed on the first surface and a second surface on the back side of the first surface is open;
A radiating element comprising a right-hand / left-handed composite transmission line disposed in a direction perpendicular to the second surface of the dielectric substrate;
A collinear antenna, comprising: a feed line that supplies power to a feed portion provided at a first end of the radiating element. Using a conductor material, a base body made of a hollow cylinder having a plurality of surfaces facing different directions on the surface side;
A plurality of dielectric substrates respectively disposed on a plurality of surfaces of the substrate;
A plurality of radiating elements composed of a right-hand / left-handed composite transmission line disposed vertically on the surfaces of the plurality of dielectric substrates, each in parallel;
A collinear antenna, comprising: a feeding line that supplies the same power to a feeding unit provided at each of first ends of the plurality of radiating elements. A dielectric substrate in which a ground plane is disposed on the first surface and a second surface on the back side of the first surface is open;
A plurality of radiating elements each comprising a right-hand / left-handed composite transmission line disposed vertically on the second surface of the dielectric substrate;
A power feed line that supplies power different in phase from each other by 180 ° to power feed portions provided at first ends of the plurality of radiating elements facing each other;
A collinear antenna, comprising: matching termination circuits provided at second end portions of the plurality of radiating elements that are separated from each other.