JP2015186093A - Yagi antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Yagi antenna which can be constructed at an installation site having no power source and can prevent snow accretion as much as possible.SOLUTION: A plurality of support rods 15, 15' are disposed almost parallel with each other so as to be perpendicular to an arm 14 with each one end fixed to the arm 14. A reflective element 13 is fixed to the other end of the support rod 15 fixed to the rear part of the arm 14, a feeding part 11 for supporting the center part of a radiation element 10 is fixed to the other end of the support rod 15' fixed to the front side of the reflective element 13, and a plurality of waveguide elements 12 are fixed to the other ends of the plurality of support rod 15 fixed to the front side of the radiation element 10 respectively. The radiation element 10, the waveguide element 12, and the reflective element 13 are disposed apart from the arm 14 by the length of the support rods 15, 15', and snow accretion to each element can be thereby prevented.

Description

  The present invention relates to a Yagi antenna that can prevent snowfall as much as possible even when set in a heavy snowfall area.

  A Yagi antenna is known as a conventional antenna that receives digital terrestrial television broadcasting. A configuration example of a conventional Yagi antenna is shown in FIG. FIG. 17 is a perspective view showing the configuration of the Yagi antenna 100, which includes a radiating element 110, a waveguide element 112, and a reflecting element 113 attached to a round bar-shaped arm 114. A power feeding unit 111 is provided at the center of the radiating element 110, and a coaxial cable is connected to an end of the radiating element 110 introduced into the power feeding unit 111 via a balanced-unbalanced converter. As a result, the reception signal received by the radiating element 110 is guided to the coaxial cable, and when the transmission signal is supplied from the coaxial cable, the transmission signal is radiated from the radiating element 110. When the Yagi antenna 100 is used as a receiving antenna, the plurality of waveguide elements 112 are arranged at predetermined intervals in the radio wave arrival direction ahead of the radiating element 110, and the reflecting elements 113 are arranged at predetermined intervals behind the radiating element 110. It is arranged with. The Yagi antenna 100 including the waveguide element 112 and the reflection element 113 has a sharp directivity due to the action of the waveguide element 112 and the reflection element 113, and gain is improved.

In order to attach the arm 114 to the antenna mast 118, U-shaped stays 116 having both ends bent are prepared, and the ends of the stays 116 are fixed to the front and rear portions of the central part of the arm 114, respectively. Yes. The stay 116 is fixed to the antenna mast 118 by the mast mounting bracket 117, so that the Yagi antenna 100 is attached to the antenna mast 118. The antenna mast 118 is generally in the shape of a pipe with a circular cross section, and is sandwiched by a mast mounting bracket 117 composed of a U-shaped bolt and a U-shaped bracket with a concave portion having a serrated edge formed inside. And fixed to the stay 116.
FIG. 18 shows another configuration example of the conventional Yagi antenna. FIG. 18 is a perspective view showing a configuration of another configuration of the Yagi antenna 200, which includes a radiating element 110, a waveguide element 112, and a reflecting element 213 attached to a round bar-shaped arm 114. FIG. Since the Yagi antenna 200 is different only in the configuration of the reflection element 213 from the configuration of the Yagi antenna 100, only the configuration of the reflection element 213 will be described. The Yagi antenna 200 includes four reflective elements 213, and the four reflective elements 213, the radiating element 110, and the waveguide element 112 are attached to a sub arm 215 that is attached substantially orthogonally to the rear end of the arm 114. Are aligned and fixed at predetermined intervals so as to be substantially parallel to each other. In this case, since the action of the four reflecting elements 213 as the reflector exceeds the action of the one reflecting element 113 as the reflector, the Yagi antenna 200 has a sharper directivity than the Yagi antenna 100, and the gain is also increased. To improve.

  When the conventional Yagi antennas 100 and 200 are installed in a heavy snowfall and there is snow on the installed Yagi antennas 100 and 200, the electrical length of the element becomes equivalently longer due to snow on the element, and the electrical performance Is known to deteriorate. Therefore, it is conceivable to prevent snow accumulation by applying water repellent coating to the Yagi antenna. In general, the water-repellent coating is peeled off over time, and the water-repellent function may be lost in several years. In order to solve this problem, it is known to provide a snow melting heater capable of melting snow in each element of the Yagi antenna to prevent deterioration of electrical performance (see Patent Document 1).

Japanese Patent No. 3524055

  However, the conventional Yagi antenna equipped with a snow melting heater has a problem of high maintenance cost because it requires a power source. In addition, when a conventional Yagi antenna including a snow melting heater is used as a relay antenna or the like, there is a case where there is no power source at the installation location, and there is a problem that it cannot be installed at the installation location without a power source.

  Then, this invention aims at providing the Yagi antenna which can be constructed in the installation place without a power supply and can prevent snowfall as much as possible.

  The Yagi antenna according to the present invention includes a plurality of support bars arranged substantially parallel to each other, one end of which is fixed to the arm so as to be substantially orthogonal to the arm, and the support bar fixed to the rear portion of the arm. A reflective element fixed to the other end of the reflector and disposed so as to be substantially orthogonal to the arm, and fixed to the other end of the support bar fixed to the arm on the front side of the reflective element, and substantially orthogonal to the arm And at the other end of the support bar fixed to the arm on the front side of the power supply unit, and a power supply unit that supports the central portion of the radiating element disposed in substantially the same plane as the surface on which the reflective element is disposed. A plurality of waveguide elements fixed to each other and substantially perpendicular to the arm and arranged in the plane, and the reflective element, the radiating element, and the waveguide element are arranged substantially parallel to each other. It is the most important feature Rukoto.

In the conventional Yagi antenna, when a radiating element, a waveguide element, and a reflecting element are assembled to the arm, each element is fixed to the arm in a crossing manner. For this reason, snow easily adheres to the crossed portion, and the attached snow becomes a lump and further swells.
In the Yagi antenna of the present invention, the power feeding part that supports the waveguide element, the reflective element, and the radiating element is fixed to the other end of the support rod that is fixed to the arm at one end. The element is assembled. Thereby, in the Yagi antenna of the present invention, it is possible to minimize the adhesion of snow to each element, and it is possible to prevent the adhered snow from becoming a lump and further expanding. Moreover, since a power supply is not required, it can construct in the installation place without a power supply.

It is a perspective view which shows the structure of the Yagi antenna concerning 1st Example of this invention. It is a perspective view which shows the fixation structure of the waveguide element in the Yagi antenna of 1st Example of this invention. It is a perspective view which shows the structure of fixation of the electric power feeding part in the Yagi antenna of 1st Example of this invention. It is a perspective view which shows the structure which adheres the support bar to the arm in the Yagi antenna of 1st Example of this invention. It is a perspective view which shows the structure of the Yagi antenna concerning 2nd Example of this invention. It is a perspective view which shows the fixation structure of the waveguide element in the Yagi antenna of 2nd Example of this invention. It is a perspective view which shows the structure of fixation of the electric power feeding part in the Yagi antenna of 2nd Example of this invention. It is a perspective view which shows the structure which fixes the support stick in the arm in the Yagi antenna of 2nd Example of this invention. It is a perspective view which shows the structure of the Yagi antenna concerning 3rd Example of this invention. It is a perspective view which shows the structure which fixes the stay and sub arm in the Yagi antenna of 3rd Example of this invention to an arm. It is a perspective view which shows the structure which fixes the stay in the arm in the Yagi antenna of 3rd Example of this invention. It is a perspective view which shows the structure of the Yagi antenna concerning 4th Example of this invention. It is a perspective view which shows the structure which adheres the stay in the arm in the Yagi antenna of 4th Example of this invention. It is a top view which shows the dimension of the Yagi antenna concerning 3rd Example of this invention. It is a side view which shows the other dimension of the Yagi antenna concerning 3rd Example of this invention. It is a perspective view which shows the outline of the other structure of the support rod and waveguide element of a Yagi antenna concerning this invention. It is a perspective view which shows the structure of the conventional Yagi antenna. It is a perspective view which shows the structure of the other conventional Yagi antenna.

FIG. 1 is a perspective view showing the configuration of the Yagi antenna according to the first embodiment of the present invention.
As shown in FIG. 1, the Yagi antenna 1 according to the first embodiment of the present invention is an antenna capable of receiving digital terrestrial television broadcasting, and includes one radiating element 10 and a plurality of (shown). In this case, 18 waveguide elements 12 and one reflecting element 13 are provided. The plurality of waveguide elements 12 are arranged at a predetermined interval in front of the radiating element 10, and the reflecting elements 13 are arranged at a predetermined interval behind the radiating element 10. The plurality of waveguide elements 12 and the reflecting elements 13 are respectively connected to the arm 14 via a round bar-like support bar 15 which is fixed at one end to the lower surface of the round bar-like arm 14 and extends downward so as to be substantially orthogonal to the arm 14. It is assembled to. Further, the central portion of the half-radiated radiating element 10 is supported by a power supply unit 11 having a rectangular box shape, and this power supply unit 11 is connected to the arm 14 via a support bar 15 ′ having substantially the same length as the support bar 15. It is assembled so as to be arranged downward. The upper ends of the support rods 15 and 15 'having a slightly smaller diameter than the arm 14 are fixed to the lower surface of the arm 14, and the power supply unit 11, the waveguide element 12 and the reflection are respectively attached to the lower ends of the support rods 15 and 15'. Each element 13 is fixed. All the support bars 15, 15 'are arranged substantially parallel to each other.

  In this case, the support rods 15, which is the sum of the number of waveguide elements 12 and the number of reflection elements 13, have the same length and are arranged substantially parallel to each other. For this reason, the plurality of waveguide elements 12 and the reflection elements 13 are arranged in the same horizontal plane below the arm 14 and spaced apart by the length of the support rod 15. In addition, since the support bar 15 ′ is substantially the same length as the support bar 15 and is arranged substantially in parallel, the radiating element 10 supported by the power feeding unit 11 includes a plurality of waveguide elements 12 and reflection elements 13. It will be located in the same plane as the horizontal plane. A coaxial cable (not shown) for propagating the reception signal received by the Yagi antenna 1 to the outside is led out from the power feeding unit 11, and the coaxial cable is balanced and unbalanced at the end of the radiating element 10 introduced into the power feeding unit 11. It is connected via a balanced converter. When a transmission signal is supplied from the coaxial cable, the transmission signal is radiated toward the front of the radiating element 10. The Yagi antenna 1 according to the first embodiment including the radiating element 10, the waveguide element 12, and the reflection element 13 disposed in substantially the same horizontal plane is moved forward of the Yagi antenna 1 by the action of the waveguide element 12 and the reflection element 13. The directivity to is sharpened, and the gain is improved.

  In order to attach the Yagi antenna 1 of the first embodiment to the antenna mast 18, U-shaped stays 16 having both ends bent are prepared, and the stays are respectively provided on the upper surfaces of the front and rear of the central part of the arm 14. Both ends of 16 are fixed. The horizontal portion of the stay 16 is fixed to the antenna mast 18 by the mast mounting bracket 17 so that the Yagi antenna 1 is attached to the antenna mast 18. The antenna mast 18 is generally shaped like a metal pipe having a circular cross section, and is erected substantially vertically. However, the antenna mast 18 is fixed to the horizontal portion of the stay 16 with a screw and has a concave U-shaped cross section. The antenna mast 18 is clamped and fixed to the stay 16 by a mast mounting bracket 17 composed of a letter-shaped bracket and a U-shaped bolt having both ends inserted into the U-shaped bracket. A serrated projection that bites into the outer peripheral surface of the antenna mast 18 is formed at the edge of the recess. As shown in FIG. 1, the Yagi antenna 1 can receive a horizontally polarized digital terrestrial television broadcast by attaching the Yagi antenna 1 to a vertically arranged antenna mast 18 so as to be horizontally arranged. it can.

  Then, the feeding portion 11, the waveguide element 12, and the reflecting element 13 are located below the arm 14 through support rods 15 and 15 ′ having predetermined lengths fixed to the arm 14 so as to hang downward from the arm 14, respectively. The support rods 15 and 15 'are separated from each other by the length of the support rods 15 and 15'. As a result, the radiating element 10, the waveguide element 12, and the reflecting element 13 and the arm 14 are assembled so as not to cross each other, so that the amount of snow that adheres to each element can be kept to a minimum. It is possible to prevent snow adhering to adjacent elements in element 1 from being united and swollen. For this reason, even if the Yagi antenna 1 of the first embodiment is installed in a heavy snowfall region, it is possible to prevent snowfall as much as possible and to prevent deterioration of electrical performance.

The perspective view which shows the structure which adheres the waveguide element 12 in the Yagi antenna 1 of 1st Example to the support rod 15 is shown to Fig.2 (a) (b).
When the waveguide element 12 is fixed to the support rod 15, the lower end of the support rod 15 disposed substantially orthogonally is aligned with the upper surface at the substantially center of the waveguide element 12 as shown in FIG. To do. An insertion hole 12a penetrating in a direction substantially perpendicular to the axial direction is formed in the approximate center of the waveguide element 12, and a concave curved surface portion 15b is formed in the lower end surface of the support bar 15, along the central axis. A tap hole 15a is formed. Therefore, the mounting screw 19 a is inserted into the insertion hole 12 a of the waveguide element 12 from below, and the mounting screw 19 a protruding from the upper surface of the waveguide element 12 is screwed into the tap hole 15 a of the support rod 15. The screwed state is shown in FIG. 2 (b), and the outer peripheral surface of the waveguide element 12 is in close contact with the concave curved surface portion 15 b at the lower end of the support rod 15 as shown in FIG. The waveguide element 12 is fixed substantially orthogonal to the lower end. The concave curved surface portion 15 b has substantially the same shape as the outer peripheral surface of the waveguide element 12. The structure in which the reflecting element 13 is fixed to the support bar 15 is the same as the structure in which the waveguide element 12 is fixed to the support bar 15.

Moreover, the perspective view which shows the structure which adheres the electric power feeding part 11 in the Yagi antenna 1 of 1st Example to support rod 15 'is shown to Fig.3 (a) (b).
The power supply unit 11 includes a box-shaped power supply box 11a having an upper surface opened and a lid portion 11b fitted to close the upper surface of the power supply box 11a, and a pair of L-shaped metal fittings on the upper surface of the lid portion 11b. 11c is arrange | positioned so that it may face, and it adheres to the cover part 11b with the fixing screw 11f. The L-shaped metal fitting 11c is composed of a flat portion that comes into contact with the lid portion 11b and an upright portion that is bent so as to stand up from the flat portion, and the left and right sides of the upright portion are bent outward. A pair of L-shaped metal fittings 11c are arranged so that the outer surfaces of the upright parts face each other, and two fixing screws 11f inserted through two holes formed in the flat part of each L-shaped metal fitting 11c are covered with a lid. A pair of L-shaped metal fittings 11c are fixed to the upper surface of the lid portion 11b by being screwed onto the upper surface of the 11b. Then, a mounting portion having a substantially rectangular cross section is formed by the pair of L-shaped metal fittings 11c facing the upright portions whose both sides are bent. On the other hand, the support rod 15 ′ for assembling the power feeding portion 11 to the arm 14 is different in the configuration of the lower end portion from the support rod 15 for assembling the waveguide element 12 or the reflective element 13 to the arm 14. That is, the support bar 15 'is formed as a flat portion 15c in which both side surfaces of the lower end portion are processed into a flat shape and the lower end portion has a substantially rectangular cross section. The flat portion 15c having a rectangular cross section is inserted from above into the mounting portion formed by the upstanding portions facing the pair of L-shaped metal fittings 11c, and is formed above and below the upstanding portion of one L-shaped metal fitting 11c. The mounting screws 11d inserted through the pair of holes 11g are respectively inserted into the two insertion holes 15d formed above and below the flat portion 15c, and 2 formed above and below the standing portion of the L-shaped metal fitting 11c on the opposite side. Two nuts 11e are screwed onto the tips of the mounting screws 11d protruding from the two holes 11g. By fastening the nut 11e, the power feeding portion 11 is fixed to the lower end of the support bar 15 ′ as shown in FIG. At this time, the radiating element 10 supported by the power feeding unit 11 is disposed substantially orthogonal to the support bar 15 ′.

Further, FIGS. 4A and 4B are perspective views showing a configuration in which the support rods 15 and 15 ′ of the Yagi antenna 1 of the first embodiment are fixed to the arm 14.
When the support rods 15 and 15 'are fixed to the arm 14, as shown in FIG. 4A, the support rod 15 disposed substantially orthogonal to the arm 14 is disposed on the lower surface of the arm 14 disposed substantially in a horizontal plane. , 15 'is aligned. The arm 14 is formed with an insertion hole 14a penetrating in a direction substantially perpendicular to the axial direction. A concave curved surface portion 15f is formed on the upper end surfaces of the support rods 15 and 15 ', and a tapped hole is formed along the central axis. 15e is formed. Therefore, the mounting screw 19b is inserted into the insertion hole 14a of the arm 14 from above, and the mounting screw 19b protruding from the lower surface of the arm 14 is screwed into the tap hole 15e of the support rods 15 and 15 ′. The screwed state is shown in FIG. 4B. As shown in this figure, the outer peripheral surface of the arm 14 is in close contact with the concave curved surface portion 15f at the upper ends of the support rods 15 and 15 ', and the support rod 15 is attached. , 15 'are fixed to the arm 14. The concave curved surface portion 15 f has substantially the same shape as the outer peripheral surface of the arm 14.

Next, a perspective view showing the configuration of the Yagi antenna 2 of the second embodiment of the present invention is shown in FIG.
As shown in FIG. 5, the Yagi antenna 2 according to the second embodiment of the present invention has a configuration in which the top and bottom of the Yagi antenna 1 of the first embodiment is reversed except for a configuration in which the feeding portion 11 is fixed. In other words, in the Yagi antenna 2 of the second embodiment, the plurality of waveguide elements 12 and one reflection element 13 are respectively connected to the arm 14 via the support rod 15 extended upward substantially orthogonal to the arm 14. It is assembled above. The central portion of the half-radiated radiating element 10 is supported by a power supply unit 11 having a rectangular box shape, and the power supply unit 11 is assembled above the arm 14 via a support bar 15 ′. The lower ends of the support bars 15 and 15 ′ are fixed to the upper surface of the arm 14, and the power feeding unit 11, the waveguide element 12 and the reflection element 13 are fixed to the upper ends of the support bars 15 and 15 ′, respectively. That is, the radiating element 10, the plurality of waveguide elements 12, and the reflecting element 13 supported by the power feeding unit 11 are provided above the arm 14 and spaced apart by the length of the support rods 15 and 15 ′. Located in the same horizontal plane. The Yagi antenna 2 of the second embodiment including the radiating element 10, the plurality of waveguide elements 12, and the reflective element 13 arranged in the same horizontal plane is also affected by the action of the waveguide element 12 and the reflective element 13. The directivity of the front is sharpened and the gain is improved. As described above, the Yagi antenna 2 according to the second embodiment is configured such that the feeding portion 11, the waveguide element 12, and the reflection element 13 are disposed above the arm 14.

Both end portions of the stay 16 are fixed to the lower surfaces of the front portion and the rear portion of the central portion of the arm 14, respectively. The horizontal portion of the stay 16 is fixed to the antenna mast 18 by the mast mounting bracket 17 so that the Yagi antenna 2 of the second embodiment is attached to the antenna mast 18. As shown in FIG. 5, the Yagi antenna 2 of the second embodiment is attached to an antenna mast 18 erected vertically so that the Yagi antenna 2 of the second embodiment is horizontally arranged. Terrestrial digital TV broadcasts.
The support rods 15 and 15 'having a predetermined length are fixed substantially orthogonal to the upper surface of the arm 14, and the power feeding section 11, the waveguide element 12 and the reflection element fixed to the upper ends of the support bars 15 and 15'. 13 is mounted on the arm 14 so as to be separated from the arm 14 by the length of the support rods 15 and 15 ′. As a result, the radiating element 10, the waveguide element 12, the reflecting element 13, and the arm 14 are assembled so as not to cross each other, so that the amount of snow on each element can be kept to a minimum. It is possible to prevent adjacent elements in the Yagi antenna 2 of the example from adhering to each other and snow from being combined and swollen. For this reason, even if the Yagi antenna 2 of the second embodiment is installed in a heavy snowy area, it is possible to prevent snowfall as much as possible and to prevent deterioration of electrical performance.

FIGS. 6A and 6B are perspective views showing a configuration in which the waveguide element 12 in the Yagi antenna 2 of the second embodiment is fixed to the support rod 15.
When the waveguide element 12 is fixed to the support rod 15, the upper end of the support rod 15 arranged substantially orthogonally is aligned with the lower surface at the center of the waveguide element 12 as shown in FIG. To do. An insertion hole 12a penetrating in a direction substantially orthogonal to the axial direction is formed in the approximate center of the waveguide element 12, and a concave curved surface portion 15b is formed in the upper end surface of the support bar 15, along the central axis. A tap hole 15a is formed. Therefore, the mounting screw 19 a is inserted into the insertion hole 12 a of the waveguide element 12 from above, and the mounting screw 19 a protruding from the lower surface of the waveguide element 12 is screwed into the tap hole 15 a of the support rod 15. The screwed state is shown in FIG. 6B, and the outer peripheral surface of the waveguide element 12 is in close contact with the concave curved surface portion 15b at the upper end of the support rod 15 as shown in FIG. The waveguide element 12 is fixed substantially orthogonal to the upper end. The concave curved surface portion 15 b has substantially the same shape as the outer peripheral surface of the waveguide element 12. The structure in which the reflecting element 13 is fixed to the support bar 15 is the same as the structure in which the waveguide element 12 is fixed to the support bar 15.

Moreover, the perspective view which shows the structure which fixes the electric power feeding part 11 in the support bar 15 'in the Yagi antenna 2 of 2nd Example is shown to Fig.7 (a) (b).
In the power supply unit 11, a pair of L-shaped metal fittings 11c are arranged so as to face each other on the lower surface of the power supply box 11a in which the lid portion 11b is fitted so as to close the opened upper surface, and a power supply box by a fixing screw 11f (not shown). It is fixed to the lower surface of 11a. A mounting portion having a substantially rectangular cross section is formed by a pair of L-shaped metal fittings 11c which are fixed to the lower surface of the power supply box 11a with the upright portions whose both sides are bent facing each other. Further, the support rod 15 ′ for assembling the power feeding portion 11 to the arm 14 is a flat portion 15 c in which both side surfaces of the upper end portion are processed into a flat shape and the cross section of the upper end portion is substantially rectangular. The flat portion 15c having a rectangular cross section is inserted from below into the mounting portion formed by the upstanding portions facing the pair of L-shaped metal fittings 11c, and is formed above and below the upstanding portion of the one L-shaped metal fitting 11c. The mounting screws 11d respectively inserted into the two holes 11g are inserted into the two insertion holes 15d formed above and below the flat portion 15c, respectively, and 2 formed above and below the upright portion of the opposite L-shaped metal fitting 11c. Two nuts 11e are screwed onto the tips of the mounting screws 11d protruding from the two holes 11g. By fastening the nut 11e, the power feeding portion 11 is fixed to the upper end of the support bar 15 ′ as shown in FIG. 7B. At this time, the radiating element 10 supported by the power feeding unit 11 is disposed substantially orthogonal to the support bar 15 ′.

Further, FIGS. 8A and 8B are perspective views showing a configuration in which the support rods 15 and 15 ′ in the Yagi antenna 2 of the second embodiment are fixed to the arm 14. FIG.
When the support rods 15 and 15 ′ are fixed to the arm 14, the lower ends of the support rods 15 and 15 ′ arranged substantially orthogonal to the upper surface of the arm 14 are aligned as shown in FIG. . The arm 14 is formed with an insertion hole 14a penetrating in a direction substantially orthogonal to the axial direction. A concave curved surface portion 15f is formed on the lower end surface of the support rods 15 and 15 ', and a tapped hole is formed along the central axis. 15e is formed. Therefore, the mounting screw 19b is inserted into the insertion hole 14a of the arm 14 from below, and the mounting screw 19b protruding from the upper surface of the arm 14 is screwed into the tap hole 15e of the support rods 15 and 15 ′. The screwed state is shown in FIG. 8B. As shown in this figure, the outer peripheral surface of the arm 14 is in close contact with the concave curved surface portion 15f at the lower ends of the support rods 15 and 15 ', and the support rod 15 is attached. , 15 ′ are fixed to the arm. The concave curved surface portion 15 f has substantially the same shape as the outer peripheral surface of the arm 14.

Next, a perspective view showing the configuration of the Yagi antenna 3 according to the third embodiment of the present invention is shown in FIG.
As shown in FIG. 9, the Yagi antenna 3 according to the third embodiment of the present invention has the same configuration as that of the Yagi antenna 1 of the first embodiment except for the configuration of the reflection element 23. That is, in the Yagi antenna 3 of the third embodiment, the sub-arm 25 is fixed to the rear part of the arm 14 so as to be substantially orthogonal to the arm 14 and to extend downward from the arm 14. A reflective element 23 is attached. Since the other configuration is the same as that of the Yagi antenna 1 of the first embodiment, the description thereof will be omitted, but the support rod 15 having a predetermined length fixed to the arm 14 so as to be substantially orthogonal to the lower side from the arm 14. , 15 ′, the power feeding unit 11 that supports the radiating element 10 and the waveguide element 12 are assembled. As a result, the radiation element 10 and the waveguide element 12 are assembled to the arm 14 so that the radiation element 10 and the waveguide element 12 are located in the same horizontal plane, separated by the length of the support rods 15 and 15 ′ below the arm 14. Further, the horizontal plane passes through substantially the center of the sub arm 25, and the horizontal plane is sandwiched between the four reflecting elements 23 fixed to the sub arm 25. For this reason, in the Yagi antenna 3 of the third embodiment, the directivity ahead of the Yagi antenna 3 is sharpened by the action of the waveguide element 12 and the plurality of reflecting elements 23, and the gain is further improved. Further, the Yagi antenna 3 of the third embodiment is assembled so that the radiating element 10 and the waveguide element 12 and the arm 14 do not cross each other, and the plurality of reflecting elements 23 are arranged on the sub-arm 25 arranged substantially orthogonally. Since it is fixed, the amount of snow on each element can be kept to a minimum, and the snow adhering to the adjacent elements and elements in the Yagi antenna 3 of the third embodiment is united and swells. This can be prevented. For this reason, even if the Yagi antenna 3 of the third embodiment is installed in a heavy snowy region, it is possible to prevent snowfall as much as possible and to prevent deterioration of electrical performance.

Both end portions of the stay 16 are fixed to the upper surfaces of the front and rear portions of the center portion of the arm 14, and the rear end portion of the stay 16 and the upper end of the sub arm 25 are connected to the arm 14 by a pair of cross fittings 26 described later. Secured to the rear. FIGS. 10A and 10B are perspective views showing a configuration in which the stay 16 and the sub arm 25 are fixed to the arm 14 in the Yagi antenna 3 of the third embodiment.
As shown in FIG. 10A, the rear end surface of the stay 16 faces the upper surface of the rear portion of the arm 14 and the upper end surface of the sub arm 25 faces the lower surface of the rear portion of the arm 14. Let Two insertion holes 14b penetrating the rear side surface of the arm 14 are formed side by side in the axial direction, and two insertion holes 16a penetrating the side surface of the rear end portion of the stay 16 are formed side by side in the axial direction. The two insertion holes 25a penetrating the side surface of the upper end portion are formed side by side in the axial direction. Then, a pair of cross metal fittings 26 are arranged on both sides so as to sandwich the rear portion of the arm 14, the rear end portion of the stay 16, and the upper end portion of the sub arm. Then, two attachment screws 27a are respectively inserted into two long holes 26b formed on both sides of the central portion extending in the lateral direction of one cross fitting 26, and the attachment screws 27a passing through the cross fitting 26 are attached to the arm 14 respectively. The two long holes formed on both sides of the central portion extending in the lateral direction of the other cross fitting 26 with the mounting screws 27a passing through the two insertion holes 14b formed in the arm 14 and passing through the insertion holes 14b of the arm 14, respectively. 26b is inserted. Then, nuts 28a are respectively screwed onto the tips of the two mounting screws 27a that have passed through the long hole 26b of the other cross fitting 26.

Further, two mounting screws 27 a are respectively inserted into two insertion holes 26 a formed at the upper and lower portions of the upper portion of one cross metal fitting 26, and the attachment screws 27 a passing through the cross metal fitting 26 are formed on the stay 16. The mounting screws 27a that pass through the two insertion holes 16a and pass through the insertion holes 16a of the stay 16 are inserted into the two insertion holes 26a formed on the upper and lower portions of the other cross metal fitting 26, respectively. Then, nuts 28a are respectively screwed onto the tips of the two mounting screws 27a that have passed through the insertion holes 26a of the other cross fitting 26.
Further, two mounting screws 27a are respectively inserted into two insertion holes 26a formed on the upper and lower portions of the lower part of one cross metal fitting 26, and the attachment screws 27a passing through the cross metal fitting 26 are formed in the sub arm 25. The mounting screws 27a are respectively inserted into the two insertion holes 25a and passed through the insertion holes 25a of the sub arm 25, and are inserted into the two insertion holes 26a formed at the upper and lower portions of the other cross metal fitting 26. Then, nuts 28a are respectively screwed onto the tips of the two mounting screws 27a that have passed through the insertion holes 26a of the other cross fitting 26.
By tightening six nuts 28a screwed to a total of six mounting screws 27a sandwiching the pair of cross fittings 26, the rear end portion of the stay 16 and the sub arm 25 are secured as shown in FIG. The upper end of the arm 14 is fixed to the rear portion of the arm 14 by a pair of cross fittings 26.
It should be noted that the upper and lower edges of the central portion of the cross fitting 26 and the left and right edges of the upper and lower portions are bent in the same direction, and the pair of cross fittings 26 has the arms 14 so that the bent edges face each other. The rear part, the rear end part of the stay 16 and the upper end part of the sub arm are arranged so as to sandwich the rear part.

Next, FIGS. 11A and 11B are perspective views showing a configuration in which the front end portion of the stay 16 in the Yagi antenna 3 of the third embodiment is fixed to the arm 14.
As shown in FIG. 11A, the front end surface of the stay 16 is positioned so as to face the front upper surface of the central portion of the arm 14. Two insertion holes 14c penetrating the front side surface of the central portion of the arm 14 are formed side by side in the axial direction, and two insertion holes 16b penetrating the side surface of the front end portion of the stay 16 are formed side by side in the axial direction. ing. Then, the pair of T-shaped metal fittings 29 are arranged on both sides with the top and bottom reversed so as to sandwich the front end of the central portion of the arm 14 and the front end portion of the stay 16. Then, two mounting screws 27b are respectively inserted into two long holes 29b formed on both sides of the head portion extending in the lateral direction in one T-shaped bracket 29, and the mounting screws 27b passing through the T-shaped bracket 29 are inserted. 2 formed on both sides of the head extending in the lateral direction of the other T-shaped metal fitting 29 with the mounting screws 27b passing through the two insertion holes 14c formed in the arm 14 and passing through the insertion holes 14c of the arm 14, respectively. The two long holes 29b are inserted. Then, two nuts 28 b are screwed to the tips of the two mounting screws 27 b that have passed through the long hole 29 b of the other T-shaped metal fitting 29.

Further, two mounting screws 27b are respectively inserted into two insertion holes 29a formed above and below the vertical bar in one T-shaped bracket 29, and the mounting screws 27b passing through the T-shaped bracket 29 are formed on the stay 16. The mounting screws 27b that are inserted through the two insertion holes 16b and through the insertion 16b of the stay 16 are inserted into the two insertion holes 29a formed above and below the vertical bar in the other T-shaped metal fitting 29, respectively. Then, two nuts 28 b are screwed to the tips of the two mounting screws 27 b that have passed through the insertion holes 29 a of the other T-shaped metal fitting 29.
By fastening four nuts 28b screwed to a total of four mounting screws 27b sandwiching the pair of T-shaped metal fittings 29, the front end portion of the stay 16 becomes a pair as shown in FIG. The T-shaped metal fitting 29 is fixed to the front of the central portion of the arm 14.
The upper and lower edges of the head of the T-shaped bracket 29 and the left and right edges of the vertical bar are bent in the same direction, and the pair of T-shaped brackets 29 are armed so that the bent edges face each other. 14 is disposed so as to sandwich the front end of the center portion of 14 and the front end portion of the stay 16.
Further, the structure in which the front end portion of the stay 16 is fixed to the arm 14 using a pair of T-shaped metal fittings 29 shown in FIGS. 11A and 11B is formed at the central portion of the arm 14 in the Yagi antenna 1 of the first embodiment. The present invention can be applied to a configuration in which both ends of the stay 16 are fixed to the upper surfaces of the front side and the rear side.

Next, a perspective view showing the configuration of the Yagi antenna 4 of the fourth embodiment of the present invention is shown in FIG.
As shown in FIG. 12, the Yagi antenna 4 according to the fourth embodiment of the present invention has the same configuration as that of the Yagi antenna 2 according to the second embodiment except for the configuration of the reflecting element 23. That is, in the Yagi antenna 4 of the fourth embodiment, the sub-arm 25 is fixed to the rear portion of the arm 14 so as to be substantially orthogonal to the arm 14 and extend upward from the arm 14. A reflective element 23 is attached. Since the other configuration is the same as that of the Yagi antenna 2 of the second embodiment, the description thereof is omitted, but the support rod 15 having a predetermined length fixed to the arm 14 so as to be substantially orthogonal to the upper side from the arm 14. , 15 ′, the power feeding unit 11 that supports the radiating element 10 and the waveguide element 12 are assembled. As a result, the radiating element 10 and the waveguide element 12 are assembled to the arm 14 so that the radiating element 10 and the waveguide element 12 are located in the same horizontal plane, separated from the arm 14 by the length of the support rods 15 and 15 ′. Further, the horizontal plane passes through substantially the center of the sub arm 25, and the horizontal plane is sandwiched between the four reflecting elements 23 fixed to the sub arm 25. For this reason, in the Yagi antenna 4 of the fourth embodiment, the directivity ahead of the Yagi antenna 4 is made sharper by the action of the waveguide element 12 and the plurality of reflecting elements 23, and the gain is further improved. Further, the Yagi antenna 4 of the fourth embodiment is assembled so that the radiating element 10 and the waveguide element 12 and the arm 14 do not cross each other, and the plurality of reflecting elements 23 are arranged on the sub-arm 25 arranged substantially orthogonally. Since it is fixed, the amount of snow on each element can be kept to a minimum, and the snow adhering to the adjacent elements and elements in the Yagi antenna 4 of the fourth embodiment is combined and swells. This can be prevented. For this reason, even if the Yagi antenna 4 of the fourth embodiment is installed in a heavy snowy area, it is possible to prevent snowing as much as possible and to prevent deterioration of electrical performance.

Also in the Yagi antenna 4 of the fourth embodiment, both end portions of the stay 16 are fixed to the upper surfaces of the front and rear portions of the central portion of the arm 14, and the rear end portion of the stay 16 and the upper end of the sub arm 25 are A pair of cross fittings 26 are fixed to the rear portion of the arm 14. The configuration in which the rear end portion of the stay 16 and the upper end of the sub arm 25 are fixed to the rear portion of the arm 14 with a pair of cross fittings 26 is a configuration in which the top and bottom of the configuration shown in FIGS. Therefore, the description is omitted.
FIGS. 13A and 13B are perspective views showing a configuration in which the front end portion of the stay 16 in the Yagi antenna 4 of the fourth embodiment is fixed to the arm 14. As shown in FIG. 13A, the front end surface of the stay 16 is positioned so as to face the front lower surface of the central portion of the arm 14. Two insertion holes 14c penetrating the front side surface of the central portion of the arm 14 are formed side by side in the axial direction, and two insertion holes 16b penetrating the side surface of the front end portion of the stay 16 are formed side by side in the axial direction. ing. Then, a pair of T-shaped metal fittings 29 are arranged on both sides so as to sandwich the front side of the center portion of the arm 14 and the front end portion of the stay 16. Two mounting screws 27b are respectively inserted into two long holes 29b formed on both sides of the head extending in the lateral direction in one T-shaped bracket 29, and the mounting screws 27b passing through the T-shaped bracket 29 are attached to the arm 14 respectively. The two long holes formed on both sides of the head extending in the lateral direction in the other T-shaped metal fitting 29 are inserted through the two insertion holes 14c formed in the arm 14 and the mounting screws 27b passing through the insertion holes 14c of the arm 14 respectively. The hole 29b is inserted. Then, two nuts 28 b are screwed to the tips of the two mounting screws 27 b that have passed through the long hole 29 b of the other T-shaped metal fitting 29.

Further, two mounting screws 27b are respectively inserted into two insertion holes 29a formed above and below the vertical bar in one T-shaped bracket 29, and the mounting screws 27b passing through the T-shaped bracket 29 are formed on the stay 16. The mounting screws 27b that are inserted through the two insertion holes 16b and through the insertion 16b of the stay 16 are inserted into the two insertion holes 29a formed above and below the vertical bar in the other T-shaped metal fitting 29, respectively. Then, two nuts 28 b are screwed to the tips of the two mounting screws 27 b that have passed through the insertion holes 29 a of the other T-shaped metal fitting 29.
By fastening four nuts 28b screwed to a total of four mounting screws 27b sandwiching the pair of T-shaped metal fittings 29, the front end portion of the stay 16 becomes a pair as shown in FIG. 13 (b). The T-shaped metal fitting 29 is fixed to the front of the central portion of the arm 14.
The upper and lower edges of the head of the T-shaped bracket 29 and the left and right edges of the vertical bar are bent in the same direction, and the pair of T-shaped brackets 29 are armed so that the bent edges face each other. 14 is disposed so as to sandwich the front end of the center portion of 14 and the front end portion of the stay 16.
Further, the structure in which the front end portion of the stay 16 is fixed to the arm 14 using a pair of T-shaped metal fittings 29 shown in FIGS. 13A and 13B is the center portion of the arm 14 in the Yagi antenna 2 of the second embodiment. The present invention can be applied to a configuration in which both end portions of the stay 16 are fixed to the lower surfaces of the front and rear portions.

By the way, the theoretical dimensions of the Yagi antenna are that the length of the radiating element is about λ / 2 and the length of the waveguide element is about λ / 2, where λ is the wavelength of the center frequency of the used frequency band. The length is slightly shorter, and the length of the reflective element is slightly longer than about λ / 2. Further, the distance between the radiating element and the waveguide element and the distance between the radiating element and the reflecting element are set to about λ / 4.
The Yagi antennas 1 to 4 of the first to fourth embodiments of the present invention described above are antennas that receive terrestrial digital television broadcasts, and the frequency band of terrestrial digital television broadcasts is 470 to 710 MHz. An example of the dimensions of the Yagi antennas 1 to 4 of the first to fourth embodiments at this time will be described by taking the Yagi antenna 3 of the third embodiment shown in FIGS. 14 and 15 as an example. The wavelength λ1 in the free space of the center frequency of the digital terrestrial television broadcasting frequency band (470 to 710 MHz) is about 508 mm.
In the Yagi antenna 3 of the third embodiment shown in FIGS. 14 and 15, the length L1 of the radiating element 10 is about 330 mm (about 0.650λ1), and the length L3 of the reflecting element 23 is about 350 mm (about 0.689λ1). It is said. In the waveguide element 12, the length of the waveguide element 12 in the vicinity of the radiating element 10 is increased. The length of the waveguide element 12 closest to the radiating element 10 is approximately 190 mm (approximately 0.374λ1), and is positioned at the front end. The length L2 of the waveguide element 12 is about 160 mm (about 0.315λ1). The spacing between the waveguide elements 12 is such that the spacing between the waveguide elements on the side of the radiating element 10 is narrow, about 50 mm (about 0.098λ1), and is widened toward the front, and about 140 mm (about 0.276λ1). ). Further, the length L4 of the arm 14 is about 1625 mm, the length L5 of the stay 16 is about 1015 mm, and the height L8 of the stay 16 is about 156 mm. The distance L6 between the uppermost reflective element 23 and the lowermost reflective element 23 fixed to the sub arm 25 is about 370 mm (about 0.728λ1), and the distance between the reflective elements 23 is about 124 mm (about 0.244λ1). ing. The distance L7 from the central axis of the arm 14 to the horizontal plane where the radiating element 10 and the plurality of waveguide elements 12 are located is about 260 mm (about 0.512λ1). The lengths of the support rods 15 and 15 ′ are set to be the distance L7.
The dimensions described above are not limited to the Yagi antenna 3 of the third embodiment, but are the same dimensions in the Yagi antennas 1 to 4 of the first to fourth embodiments of the present invention. The operation is not limited, and the same operation is performed even with the front and rear dimensions.

Next, FIGS. 16A and 16B are perspective views schematically showing other configurations of the support rod and the waveguide element of the Yagi antenna according to the present invention. In the configuration shown in FIG. 16A, the shape of the support bar 35 for assembling the waveguide element 12 to the arm 14 is an inverted V shape, and the central portion of the inverted V shape support bar 35 is illustrated on the lower surface of the arm 14. The waveguide element 12 is fixed to the tip of the inverted V-shaped support bar 35 which is fixed by a fixing means such as a screw.
In the configuration shown in FIG. 16B, the shape of the support bar 45 for assembling the waveguide element 12 to the arm 14 is an inverted Y shape, and the tip of the I-shaped portion of the inverted Y-shaped support rod 45 is the arm. The waveguide element 12 is fixed to the tip of the inverted Y-shaped support bar 45 which is fixed to the lower surface of the screw 14 by fixing means such as screws (not shown).

The structure of assembling the waveguide element 12 shown in FIGS. 16A and 16B below the arm 14 with the inverted V-shaped support bar 35 or the inverted Y-shaped support bar 45 is the first embodiment shown in FIG. 9 and the Yagi antenna 3 of the third embodiment shown in FIG. In this case, the configuration in which the waveguide element 12 is fixed to the inverted V-shaped support rod 35 or the inverted Y-shaped support rod 45 can be configured as shown in FIGS. Further, the configuration in which the inverted Y-shaped support bar 45 is fixed to the arm 14 can be configured as shown in FIGS.
16A and 16B is reversed, and the waveguide element 12 is assembled above the arm 14 with the V-shaped support bar 35 or the Y-shaped support bar 45. The present invention can be applied to the Yagi antenna 2 of the second embodiment shown in FIG. 5 and the Yagi antenna 4 of the fourth embodiment shown in FIG. In this case, the configuration in which the waveguide element 12 is fixed to the V-shaped support bar 35 or the Y-shaped support bar 45 can be configured as shown in FIGS. Moreover, the structure which adheres the Y-shaped support bar 45 to the arm 14 can be made into the structure shown to Fig.8 (a) (b).

Although the Yagi antenna of each embodiment of the present invention is for digital terrestrial broadcasting, the present invention is not limited to this and can be applied to a Yagi antenna of an arbitrary frequency band. When the used frequency band is changed, the dimensions of the respective parts may be changed according to the frequency of the frequency band.
In the Yagi antenna of each embodiment of the present invention described above, the radiating element, waveguide element and reflecting element are preferably made of aluminum pipes, but made of other metal pipes or conductive resin pipes. May be. The arm, sub-arm, and stay can be made of a resin pipe or a metal pipe. Moreover, although the cross-sectional shapes of the arm, the radiating element, the waveguide element, and the reflecting element are circular, they may be triangular, quadrangular, polygonal, or elliptical.

1-4 Yagi antenna, 10 Radiating element, 11 Feeding part, 11a Feeding box, 11b Cover part, 11c L-shaped bracket, 11d Mounting screw, 11e Nut, 11f Fixing screw, 11g Hole part, 12 Waveguide element, 12a Insertion hole , 13 Reflective element, 14 Arm, 14a Insertion hole, 14b Insertion hole, 14c Insertion hole, 15 Support rod, 15a Tap hole, 15b Curved part, 15c Flat part, 15d Insertion hole, 15e Tap hole, 15f Curved part, 16 Stay , 16a insertion hole, 16b insertion hole, 17 mast mounting bracket, 18 antenna mast, 19a mounting screw, 19b mounting screw, 23 reflecting element, 25 sub-arm, 25a insertion hole, 26 cross bracket, 26a insertion hole, 26b long hole, 27a Mounting screw, 27b Mounting screw, 28a nut, 28b nut, 29 T-shaped bracket 29a insertion hole, 29b long hole, 35 support rod, 45 support rod, 100, 200 Yagi antenna, 110 radiating element, 111 feeding section, 112 waveguide element, 113 reflecting element, 114 arm, 116 stay, 117 mast mounting bracket, 118 Antenna mast

Claims (6)

A plurality of support bars arranged substantially parallel to each other, one end of which is fixed to the arm so as to be substantially perpendicular to the arm;
A reflective element fixed to the other end of the support bar fixed to the rear part of the arm and arranged to be substantially orthogonal to the arm;
A radiating element fixed to the other end of the support rod fixed to the arm on the front side of the reflecting element, disposed substantially in the same plane as the surface on which the reflecting element is disposed and substantially orthogonal to the arm; A power feeding part that supports the central part;
A plurality of waveguide elements fixed to the other ends of the support rods fixed to the arm on the front side of the power supply unit, and substantially orthogonal to the arm and disposed in the plane.
The Yagi antenna, wherein the reflecting element, the radiating element, and the waveguide element are arranged substantially parallel to each other. A plurality of support bars arranged substantially parallel to each other, one end of which is fixed to the arm so as to be substantially perpendicular to the arm;
A sub arm fixed to the arm substantially orthogonally to the rear of the arm;
A plurality of reflective elements fixed to the sub arm at a predetermined interval and substantially orthogonal to the arm;
A power feeding portion that is fixed to the other end of the support rod fixed to the arm on the front side of the reflecting element and supports a central portion of the radiating element that is arranged so as to be substantially orthogonal to the arm;
A plurality of rods that are respectively fixed to the other ends of the support rods fixed to the arm in front of the power feeding portion and are substantially orthogonal to the arm and disposed in substantially the same plane as the surface on which the radiating element is disposed. And a waveguide element,
The Yagi antenna, wherein the reflecting element, the radiating element, and the waveguide element are arranged substantially parallel to each other. A stay that is bent in a U-shape and has both ends fixed to the arm;
The antenna mast is clamped by an antenna mounting bracket provided on the stay, and the arm including the reflective element, the radiating element, and the waveguide element is attached to the antenna mast. Yagi antenna according to 2.   Tap holes are formed at both ends of the support bar, and an end of the support bar is formed by screwing a mounting screw inserted into the waveguide element, the reflection element, or the arm into the tap hole. The Yagi antenna according to any one of claims 1 to 3, wherein the waveguide element, the reflection element, or the arm is fixed to the antenna.  The support bar is V-shaped, the waveguide element is fixed to the tip of the V-shaped support bar, and the center of the V-shaped support bar is fixed to the arm. The Yagi antenna according to any one of claims 1 to 4, wherein:  The support rod is Y-shaped, the waveguide element is fixed to the tip of the Y-shaped support rod, and the tip of the I-shaped portion of the Y-shaped support rod is the arm. The Yagi antenna according to claim 1, wherein the Yagi antenna is fixed to the Yagi antenna.

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