JP2008113407A - Broadband antenna with reflector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a broadband antenna with a reflector capable of direct power feeding while attaining miniaturization. <P>SOLUTION: A reflecting element 21 is disposed on the back face of a radiation element 11 at a spacing of about 0.135λ. The radiation element 11 is formed approximately in a Z shape by arranging first and second antenna elements 12a, 12b formed from a plate-shaped conductive member within the same plane in the vertical direction and jointing them by joint rails 13. In central portions of the joint rails 13, a groove 16 with a predetermined width is provided in the vertical direction and in feeding projections 17a, 17b formed in the central portion thereof, feeding points 18a, 18b are formed. The first and second antenna elements 12a, 12b comprise linear elements 14 formed at outer side portions in the vertical direction and side elements 15 formed at the two end portions of the linear elements, and a width W2 of the linear elements 14 and a width W3 of the side elements 15 are set so that feeding point impedance becomes about 75 Ω. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a reflector-equipped broadband antenna in which a reflector is provided on the back surface of a radiating element.

  Conventionally, terrestrial analog TV broadcasts (VHF, UHF) and satellite broadcasts (CS / BS) are performed as TV broadcasts, but in recent years, terrestrial digital TV broadcasts have been started. Terrestrial digital broadcasting uses a high frequency band (470 to 770 MHz) of the UHF band.

  Conventionally, as an antenna for receiving a TV broadcast in the UHF band, a plurality of waveguide elements are arranged in front of a radiating element such as a linear dipole element or a folded dipole element, and a reflecting element is arranged behind the radiating element. A Yagi type antenna is generally known (for example, refer to Patent Document 1).

  In addition, as an antenna for receiving digital terrestrial TV broadcasting, a reflector such as a reflector such as a metal plate or a reflective element having a shape corresponding to the radiating element is disposed on the back surface of the radiating element such as a plate-shaped dipole element. A broadband antenna with a body is used. In the above-described broadband antenna with a reflector, the interval between the radiating element and the reflector is generally set to about ¼λ (λ is the wavelength at the center frequency of the used frequency band). When the distance between the radiating element and the reflector is set to 1 / 4λ as described above, the antenna impedance can be set to about 75Ω, and a feeding coaxial cable having an impedance of 75Ω is connected to the antenna. It can be directly connected to the power supply terminal.

However, when the distance between the radiating element and the reflector is set to about ¼λ, there is a problem that the distance between the radiating element and the reflector becomes considerably wide, and the entire antenna becomes large. Therefore, when a small and wideband antenna is required, a loop antenna is arranged as a radiating element at a distance of about 1 / 8λ, and a wide band is secured with a relatively high feeding point impedance of about 300Ω. In addition, it is matched with a 75Ω feeding coaxial cable suitable for a television receiver by an impedance conversion transformer or the like.
Japanese Utility Model Publication No. 58-164313

  Conventional broadband antennas with reflectors generally have a large antenna overall because the spacing between the radiating elements and the reflectors is generally set to about 1 / 4λ in order to ensure the broadband property of the voltage standing wave as described above. There was a tendency to become.

  In order to avoid an increase in the size of the antenna, when the distance between the radiating element and the reflector is set to about 1 / 8λ and the feed point impedance is set to a high impedance of about 300Ω, the impedance of 300Ω is changed to the impedance conversion transformer. Therefore, there is a problem in that an insertion loss of the impedance converter transformer occurs, resulting in a decrease in gain, an increase in the number of parts, and an extra part management and cost.

  In addition, the reflector-equipped antenna provided with the waveguide element in front of the radiating element can achieve high gain, but has a problem that it becomes large in the directivity direction.

  The present invention has been made to solve the above-described problem, and provides a reflector-equipped wide-band antenna that can maintain wide-band characteristics while achieving downsizing and can be directly fed without using an impedance conversion transformer. The purpose is to do.

A broadband antenna with a reflector according to a first aspect of the present invention includes a radiating element, and a reflector disposed at a predetermined interval on the back surface of the radiating element,
The radiating elements are arranged at predetermined intervals in the vertical direction within the same plane by a plate-like conductive member, and are formed at both ends of the linear elements formed on both outer sides in the vertical direction. First and second antenna elements comprising the formed side elements, a coupling line coupling between the side elements of the first antenna element and the side elements of the second antenna element, and the coupling line And a feeding point provided at substantially the center of the
The coupling line is formed such that a width of the feeding point portion is narrower than a width between side elements of the first and second antenna elements, and each side portion of the first and second antennas from the vicinity of the feeding point. It is characterized by being inclined toward the element.

  A second invention is characterized in that, in the broadband antenna with a reflector according to the first invention, an interval between the radiating element and the reflector is set in a range of about 0.125 to 0.135λ.

  According to a third invention, in the broadband antenna with a reflector according to the first or second invention, the coupling line is formed wider as it approaches a feeding point.

A broadband antenna with a reflector according to a fourth aspect of the present invention includes a radiating element, a reflecting plate disposed on the back surface of the radiating element with a spacing of about 0.25λ, and between the radiating element and the reflecting plate. A reflective element composed of a linear element arranged at a distance of about 0.125 to 0.135λ from the radiating element,
The radiating elements are arranged at predetermined intervals in the vertical direction within the same plane by a plate-like conductive member, and are formed at both ends of the linear elements formed on both outer sides in the vertical direction. First and second antenna elements comprising the formed side elements, a coupling line coupling between the side elements of the first antenna element and the side elements of the second antenna element, and the coupling line And a feeding point provided at a substantially central portion.

  According to a fifth invention, in the wideband antenna with a reflector according to the first to fourth inventions, the width of the side element is set to about 1 to 1.5 times the width of the linear element. And

  A sixth invention is the broadband antenna with a reflector according to any one of the first to fifth inventions, wherein the first and second antenna elements are formed by notching a connection portion between the linear element and the side element. It is characterized by that.

  According to a seventh invention, in the wideband antenna with a reflector according to the first to sixth inventions, the width of the side element and the width of the linear element so that a feed point impedance at the feed point is about 75Ω. Is set.

A reflector-equipped broadband antenna according to an eighth aspect of the present invention includes a radiating element, and a reflector disposed at a predetermined interval on the back surface of the radiating element,
The radiating elements are arranged at predetermined intervals in the vertical direction within the same plane by a plate-like conductive member, and are formed at both ends of the horizontal elongated elements formed on both outer sides in the vertical direction. First and second antenna elements comprising the formed side elements, a coupling line coupling between the side elements of the first antenna element and the side elements of the second antenna element, and the coupling line And a feeding point provided at substantially the center of the
The coupling line is formed such that a width of the feeding point portion is narrower than a width between side elements of the first and second antenna elements, and each side portion of the first and second antennas from the vicinity of the feeding point. Inclined toward the element, and
A distance between the radiating element and the reflector is set in a range of about 0.125 to 0.135λ;
The coupling line is formed so as to increase in width as it approaches the feeding point.

  According to the present invention, the distance between the radiating element and the reflecting element can be set to be smaller than the conventional distance of about 0.25λ, and the broadband characteristics can be maintained while the antenna is downsized. Further, the feeding point impedance can be set to about 75Ω without using an impedance conversion transformer. On the other hand, when the distance between the radiating element and the reflecting plate is kept at about 0.25λ, which is the same as the conventional one, the antenna can have a higher gain than the conventional one.

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

(First embodiment)
1A and 1B show a configuration of a UHF band receiving (horizontal polarization) reflector-attached broadband antenna 10A according to a first embodiment of the present invention, where FIG. 1A is a front view, FIG. 1B is a right side view, and FIG. ) Is a lower side view. FIG. 2 is a front view of the radiating element in the embodiment, and FIG. 3 is a front view of the reflecting element in the embodiment.

  In FIG. 1, reference numeral 11 denotes a radiating element, and a reflecting element 21 is disposed opposite to the back surface of the radiating element 11 with a predetermined distance D1. The distance D1 between the radiating element 11 and the reflecting element 21 is set to about 0.125λ to 0.135λ (λ is a wavelength at the center frequency (620 MHz) of the used frequency band). As shown in FIGS. 1 and 2, the radiating element 11 includes first and second antenna elements 12a and 12b formed of a plate-like conductive member arranged at a predetermined interval in the vertical direction within the same plane. Then, they are coupled by the coupled line 13 to form a substantially Z shape. The first and second antenna elements 12a and 12b have a predetermined width formed by bending a linear element 14 having a predetermined width on both outer sides in the vertical direction and both ends of the linear element 14 by approximately 90 °. It consists of side part elements 15 and is formed symmetrically with gaps 20a, 20b at the center. The first antenna element 12a has a shape in which a U-shape is rotated 90 ° counterclockwise, and the second antenna-like element 12b has a shape in which the U-shape is rotated 90 ° clockwise. It has become.

  The coupling line 13 has a shape in which the end portions of the side elements 15 of the first and second antenna element elements 12a and 12b are bent at a predetermined angle smaller than 90 °, for example, about 40 ° in the present embodiment. It is formed in a substantially X shape, and a groove 16 is provided in the vertical direction of the central portion. Further, the coupling line 13 is formed with feeding convex portions 17a and 17b at the center of the groove 16, and the feeding convex portions 17a and 17b are provided with feeding points 18a and 18b. In the present embodiment, the width of the coupling line 13 is gradually increased from the side element 15 to the groove 16. That is, the coupling line 13 is formed such that the outer angle B is set to a larger value than the inner angle A with respect to the longitudinal direction of the linear element 14 and becomes wider as it approaches the feeding points 18a and 18b. The angle A inside the coupling line 13 is set to about 30 ° ± 10 °, for example.

  As described above, the outer shape of the radiation element 11 is such that the outer width W8 of the feeding point portion of the coupling line 13 is narrower than the outer width W1 of the linear element 14, that is, the width between the side elements 15, 15, It is formed so as to be inclined from the vicinity toward the side element 15. In FIG. 2, a substantially funnel shape gradually increases from the feeding point portion of the coupling line 13 or the vicinity thereof toward the side element 15. That is, regarding the outer shape of the upper radiating element, the upper part of the linear element 14 is the upper side, the outer side of the side element 15 is the side, the outer side of the coupled line part is the inclined side inclined inward, and the vertical direction is below it. The feeding point portions are connected to each other. The outer shape of the lower radiating element is symmetrical with the outer shape of the upper radiating element.

  Further, the inner shape of the upper radiating element is such that the lateral width W1 ′ of the lower part (inner side) of the linear element 14 is larger than the outer lateral width W8 of the feeding point portion or the lateral width Wa of the groove 16, and is linear from the feeding point portion or the vicinity thereof. The structure gradually increases in the direction of the element 14. In FIG. 2, the structure gradually increases from the upper end of the groove 16 toward the side element 15. In other words, the inner shape of the upper radiating element is such that the lower side of the linear element 14 is the upper side, the inner side of the side element 15 is the side, the inner side of the coupled line portion is the inclined side inclined inward, and the vertical direction is below it. The groove 16 has a substantially funnel shape. The inner shape of the lower radiating element is symmetrical with the inner shape of the upper radiating element.

  The radiating element 11 formed as described above has an overall length L1 of about 0.8λ in the vertical direction and a total width, that is, the length W1 of the linear element 14 constituting the first and second antenna elements 12a and 12b is about 0. .5λ. In the first and second antenna elements 12a and 12b, the element width W2 of the linear element 14 is set to about 0.08λ, and the element width W3 of the side element 15 is set to about 0.1λ. In this case, the element width W3 of the side element 15 is set to a value larger than the width W2 of the linear element 14, for example, about 1 to 1.5 times the element width W2. Further, the left and right central element width W4 of the groove 16 in the coupled line 13 is set to about 0.05λ.

  Further, the lateral width Wa of the groove 16 is about 0.04λ, the vertical length La is about 0.11λ, the vertical length Lb of the side element outer shape is about 0.16λ, and the vertical length Lc of the inner shape is about 0.1λ, and the vertical length Ld of the coupled line outline is about 00.2λ. The outer width W8 of the feeding point is about 0.14λ.

  The reflection element 21 is composed of two loop reflection elements 22a and 22b made of linear elements as shown in FIG. The loop reflecting elements 22a and 22b are conductors having a width W5 formed in a substantially triangular shape, and have a predetermined interval so as to be positioned on the back surfaces of the first and second antenna elements 12a and 12b constituting the radiating element 11. Are arranged opposite to each other. Each of the loop reflecting elements 22a and 22b is set to have an element width W5 of about 0.01λ, an overall width W6 of about 0.55λ, and a height H of about 0.35λ.

  The reflection element 21 configured as described above is disposed on the back surface of the radiating element 11 at a distance D1 as shown in FIG. 1, and performs a reflection operation by a resonance action. In this case, the reflecting element 21 is in a state in which the upper and lower side portions and the left and right side portions slightly protrude outward from the radiating element 11.

  As shown in the first embodiment, the radiating element 11 is composed of the first and second antenna elements 12a and 12b including the linear element 14 and the side element 15, and the coupling line 13 is connected to the feeding point 18a. , 18b is formed in a substantially funnel shape so as to gradually increase toward the side element 15, and the element width W3 of the side element 15 is set to about 1 to 1.5 times the width W2 of the linear element 14. As a result, even if the distance D1 between the radiating element 11 and the reflecting element 21 is set to a narrow distance of about 0.125λ to 0.135λ, the impedance of the feeding points at the feeding points 18a and 18b is reduced to a low impedance in a wide band. 75Ω (unbalanced) can be maintained, and the feeding points 18a and 18b can be directly fed using a 75Ω coaxial cable. In addition, the coupling line 13 can be made to function as a capacitor by being formed wider as it approaches the feeding points 18a and 18b from the side element 15 and can be matched.

  The feed point impedance can be finely adjusted by, for example, the shape and line width of the coupled line 13. As a result, an impedance conversion transformer is not required, and the number of parts can be reduced to reduce the cost.

  FIG. 4 shows the VSWR characteristics when the impedance of the feeding point of the reflector-equipped broadband antenna 10A according to the first embodiment is 75Ω (unbalanced). The horizontal axis represents frequency (MHz) and the vertical axis represents VSWR. (Voltage standing wave ratio) is shown. At this time, the distance D1 between the radiating element 11 and the reflecting element 21 is 0.135λ, which is about 65 mm, that is, the antenna 10A is manufactured based on 620 MHz (λ = 484 mm) among the target frequencies of 470 to 770 MHz.

  As is clear from FIG. 4, in the reflector-equipped broadband antenna 10A according to the first embodiment, when the feed point impedance is set to 75Ω, the VSWR is set to 2. in the frequency band of 470 to 770 MHz of terrestrial digital TV broadcasting. 5 or less, a specific bandwidth of about 48% is obtained at VSWR 2.5 or less, and the broadband characteristics can be maintained.

  In the above-described embodiment, the antenna for horizontally polarized wave reception is shown. However, by rotating 90 ° and positioning the linear elements 14 of the first and second antenna elements 12a and 12b in the vertical direction, the antenna is vertically Polarization can be received.

  The dimensions of each part of the reflector-equipped broadband antenna 10A according to the present invention are not limited to the values shown in the above embodiment, and can be set to other values. It is also possible to change. FIG. 5 shows an example in which the gaps 20a and 20b formed inside the first and second antenna elements 12a and 12b constituting the radiating element 11 are formed in a substantially triangular shape. The width W1 'of the gaps 20a, 20b corresponds to the inner length of the linear element 14 in the first embodiment and can be set in the range of about 0.01 to 0.4λ. The height Le of the gaps 20a and 20b can be set in the range of about 0 to 0.2λ. The element width W2 of the linear element 14 is about 0.04 to 0.08λ, the vertical length Lb outside the side element 15 is about 0.8 to 0.16λ, and the width of the groove 16 in the coupling line 13 is Wa can be set in the range of about 0.01 to 0.04. Other dimensions such as the outer width W1 of the linear element 14, the total length L1 of the radiating element 11, the left and right central element width W4 of the groove 16 in the coupling line 13, and the like are the same as in the first embodiment. .

  Even if the radiating element 11 has the shape shown in FIG. 5 and the dimensions of each part are set as described above, substantially the same characteristics as the reflector-equipped wideband antenna 10A shown in the first embodiment can be obtained. .

  Note that the linear element 14 does not have to be completely linear. For example, even when it is a loose arc-shaped laterally long element, the effects of the present invention can be obtained, and those skilled in the art will appropriately have such a shape. Can be used instead of a straight line.

(Second Embodiment)
Next, a reflector-equipped broadband antenna according to a second embodiment of the present invention will be described.
FIG. 6 shows a configuration of a reflector-equipped broadband antenna 10B according to the second embodiment of the present invention, where (a) is a front view, (b) is a right side view, and (c) is a lower side view.

  The reflector-equipped broadband antenna 10B according to the second embodiment is configured by using a reflector 25 instead of the reflector 21 in the first embodiment. The reflection plate 25 is a metal plate formed in a square shape. The total length L2 is set to about 0.85λ and the total width W7 is set to about 0.6λ. That is, the total length L1 (about 0.8λ) of the radiating element 11 and the total width are set. It is set slightly larger than W1 (about 0.5λ).

  Since other configurations are the same as those of the reflector-equipped broadband antenna 10A according to the first embodiment, the same portions are denoted by the same reference numerals, and detailed description thereof is omitted.

  Even when the reflecting plate 25 is used instead of the reflecting element 21 as shown in the second embodiment, substantially the same characteristics as those of the broadband antenna with reflector 10A according to the first embodiment can be obtained.

(Third embodiment)
Next, a reflector-equipped broadband antenna according to a third embodiment of the present invention will be described.
FIG. 7 shows a configuration of a reflector-equipped broadband antenna 10C according to the third embodiment of the present invention, in which (a) is a front view, (b) is a right side view, and (c) is a lower side view.

  The reflector-equipped wideband antenna 10C according to the third embodiment is similar to the second embodiment shown in FIG. 6 in that both side portions of the first and second antenna elements 12a and 12b constituting the radiating element 11 are reflectors. The bent portion 19 is formed by bending a predetermined angle in the 25 direction, and the bent portion 26 is formed by bending both side portions of the reflector 25 in the direction of the radiating element 11. Since other configurations are the same as those of the reflector-equipped broadband antenna 10B according to the second embodiment, the same portions are denoted by the same reference numerals, and detailed description thereof is omitted.

  As described above, the both side tips of the first and second antenna elements 12a and 12b and the tips of both sides of the reflector 25 are bent, so that the size can be reduced. As shown in -273642), it is possible to increase the bandwidth.

(Fourth embodiment)
Next, a broadband antenna with a reflector according to a fourth embodiment of the present invention will be described.
FIG. 8 shows a specific configuration of a reflector-equipped broadband antenna 10D according to the fourth embodiment of the present invention, where (a) is a front view, (b) is a right side view, and (c) is a bottom side view. is there.

  In the fourth embodiment, the reflector-equipped broadband antenna 10B according to the second embodiment shown in FIG. 6 is housed in, for example, a cover 31 made of synthetic resin. The cover 31 has the radiating element 11 attached to the inner side of the front surface and a reflecting plate 25 attached to the inner side of the back surface. A mounting bracket 32 is attached to the center of the back surface of the cover 31, and a power supply terminal 33 is provided below the mounting bracket 32. Further, in the cover 31, the feeding points 18 a and 18 b of the radiating element 11 and the feeding terminal 33 are connected by a feeding line 34.

  The reflector-equipped broadband antenna 10D configured as described above is used by being attached to an antenna column or the like by the mounting bracket 32.

  Even when the reflector-equipped broadband antenna 10B according to the second embodiment is housed in the synthetic resin cover 31 as shown in the fourth embodiment, the antenna characteristics equivalent to those of the second embodiment are obtained. Can be held.

  In the fourth embodiment, the case where the reflector-equipped broadband antenna 10B according to the second embodiment is housed in the cover 31 made of synthetic resin has been described. However, the reflector-equipped broadband antenna 10A according to the first embodiment. Alternatively, it is needless to say that the reflector-equipped broadband antenna 10C according to the third embodiment may be housed in the synthetic resin cover 31.

(Fifth embodiment)
Next, a broadband antenna with a reflector according to a fifth embodiment of the present invention will be described.
FIG. 9 shows a configuration of a reflector-equipped broadband antenna 10E according to the fifth embodiment of the present invention, where (a) is a front view, (b) is a right side view, and (c) is a lower side view.

  In the reflector-equipped wideband antenna 10E according to the fifth embodiment, as shown in the first embodiment of FIG. 1, the reflective element 21 is disposed on the back side of the radiating element 11 with a distance of D1. A reflection plate 27 is further arranged on the back side of the reflection element 21. The reflection plate 27 is a metal plate formed in a square shape, and the same size as the reflection plate 25 in the second embodiment is used.

  The distance D1 between the radiating element 11 and the reflecting element 21 is set to about 0.135λ as in the first embodiment, and the distance D2 between the radiating element 11 and the reflecting plate 27 is set to about 0.25λ. The Since other configurations are the same as those of the reflector-equipped broadband antenna 10A according to the first embodiment, the same portions are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 10 shows the gain characteristics of the reflector-equipped broadband antenna 10E according to the fifth embodiment. The horizontal axis represents frequency (MHz) and the vertical axis represents gain (dB). In FIG. 10, a characteristic a indicated by a broken line is a gain characteristic of the broadband antenna 10E with a reflector in which the reflecting element 21 and the reflecting plate 27 are arranged on the back side of the radiating element 11 as shown in the fifth embodiment. The characteristic b shown in FIG. 6 shows the gain characteristic when the reflecting element 21 is omitted for comparison, and only the reflecting plate 27 is disposed on the back side of the radiating element 11 with a distance D2 of about 0.25λ.

  As is clear from the characteristic a and the characteristic b in FIG. 10 described above, by arranging the reflective element 21 and the reflective plate 27 on the back side of the radiating element 11, only the reflective plate 27 is provided on the back side of the radiating element 11. The gain can be improved compared to the case.

  Therefore, according to the fifth embodiment, the distance between the radiating element 11 and the reflecting plate 27 is set to about 0.25λ, and the reflecting element 21 is disposed between the radiating element 11 and the reflecting plate 27, thereby increasing the gain. Improvements can be made.

  Further, by optimizing the shape of the radiating element 11 in accordance with the characteristic impedance, the feeding point impedance at the feeding points 18a and 18b even if the distance D1 between the radiating element 11 and the reflecting element 21 is set to about 0.135λ. Can be set to about 75Ω (unbalanced), and power can be directly supplied using a 75Ω coaxial cable.

(Sixth embodiment)
Next, a broadband antenna with a reflector according to a sixth embodiment of the present invention will be described.
FIG. 11 shows a configuration of a reflector-equipped broadband antenna 10F according to the sixth embodiment of the present invention, where (a) is a front view, (b) is a right side view, and (c) is a lower side view.

  The reflector-equipped wideband antenna 10F according to the sixth embodiment is similar to the fifth embodiment shown in FIG. 9 in that both side portions of the first and second antenna elements 12a and 12b constituting the radiating element 11 are formed as reflecting elements. The bent portion 19 is formed by bending a predetermined angle in the 21 direction, and the bent portion 28 is formed by bending both side portions of the reflection plate 27 in the direction of the reflective element 21 by a predetermined angle. Other configurations are the same as those of the reflector-equipped wideband antenna according to the fifth embodiment, and thus the same parts are denoted by the same reference numerals and detailed description thereof is omitted.

  As described above, the first and second antenna elements 12a and 12b and the front end portions of the reflecting plate 27 are bent, whereby the size can be reduced and the bandwidth can be increased.

(Seventh embodiment)
Next, a broadband antenna with a reflector according to a seventh embodiment of the present invention will be described.
FIG. 12 shows a specific configuration of a reflector-equipped broadband antenna 10G according to the seventh embodiment of the present invention, where (a) is a front view, (b) is a right side view, and (c) is a bottom side view. is there.

  In the seventh embodiment, the reflector-equipped broadband antenna 10E according to the fifth embodiment shown in FIG. 9 is housed in, for example, a synthetic resin cover 31A. In this case, the radiating element 11 is attached to the inside of the front surface of the cover 31A and the reflecting plate 27 is attached to the inside of the back surface, and the distance D2 between the radiating element 11 and the reflecting plate 27 is maintained at about 0.25λ. Further, the reflection element 21 is attached to the reflection plate 27 by a holding member 36 made of an insulating material, and the distance D1 between the radiation element 11 and the reflection element 21 is held at about 0.135λ.

  A mounting bracket 32 is attached to the center of the back surface of the cover 31 </ b> A, and a power supply terminal 33 is provided below the mounting bracket 32. Further, in the cover 31 </ b> A, the feeding points 18 a and 18 b of the radiating element 11 and the feeding terminal 33 are connected by a feeding line 34.

  The reflector-equipped broadband antenna 10G configured as described above is used by being attached to, for example, an antenna column or the like with the mounting bracket 32, and obtains characteristics equivalent to those of the reflector-equipped broadband antenna 10E according to the fifth embodiment. be able to.

  In addition, in the said 7th Embodiment, although the case where the broadband antenna 10E with a reflector which concerns on 5th Embodiment was accommodated in the synthetic resin cover 31A was shown, others, for example with a reflector which concerns on 6th Embodiment Of course, the broadband antenna 10F may be housed in the synthetic resin cover 31A.

(Eighth embodiment)
Next, a broadband antenna with a reflector according to an eighth embodiment of the present invention will be described.
FIG. 13 shows the configuration of a reflector-equipped broadband antenna 10H according to the eighth embodiment of the present invention, where (a) is a front view, (b) is a right side view, and (c) is a lower side view.

  In the eighth embodiment, the reflector-equipped broadband antenna 10E according to the fifth embodiment shown in FIG. 9 uses a triangular double loop radiating element 11A instead of the radiating element 11. In the radiating element 11 </ b> A, substantially triangular loop elements 41 a and 41 b are arranged in an upper part and a lower part by a conductive line having a predetermined width, and both are coupled by a feed line 42. The feeding line 42 is provided with feeding projections 17a and 17b at the center, and feeding points 18a and 18b are formed on the feeding projections 17a and 17b. Other configurations are the same as those of the reflector-equipped broadband antenna 10E according to the fifth embodiment, and thus the same portions are denoted by the same reference numerals and detailed description thereof is omitted.

  When the triangular double loop type radiating element 11A is used as described above, the feeding point impedance is larger than 75Ω, but the gain can be improved by providing the reflecting element 21 and the reflecting plate 27 on the back surface of the radiating element 11A. it can. In addition, the configuration of the radiating element 11A can be simplified.

(Ninth embodiment)
Next, a broadband antenna with a reflector according to a ninth embodiment of the present invention will be described.
14A and 14B show the configuration of the radiating element and the reflecting element of the reflector-equipped broadband antenna according to the ninth embodiment of the present invention. FIG. 14A is a front view of the radiating element, and FIG. 14B is a front view of the reflecting element. .

  The ninth embodiment uses a radiating element 11B using a dipole stack in place of the radiating element 11 in the reflector-equipped broadband antenna 10E according to the fifth embodiment, and replaces the reflecting element 21 with a linear reflection. The element 48 is used.

  In the radiating element 11B, dipole stacks 44 and 45 formed by conductive lines having a predetermined width are arranged in the vertical direction at a predetermined interval in the same plane, and the dipole stacks 44 and 45 are coupled by a feed line 46. . The feeding line 46 is provided with feeding points 18a and 18b on feeding convex portions formed at the center.

  The reflecting element 48 is arranged with linear elements 49a and 49b in the vertical direction at predetermined intervals, that is, corresponding to the dipole stacks 44 and 45, respectively. Other configurations are the same as those of the reflector-equipped broadband antenna 10E according to the fifth embodiment, and thus detailed description thereof is omitted. Although not shown in FIG. 14, the reflector 27 is provided on the back surface of the reflective element 48 as in the reflector-equipped broadband antenna 10 </ b> E according to the fifth embodiment.

  When the radiating element 11B using the dipole stack is used as described above, the feeding point impedance becomes larger than 75Ω, but the gain can be improved by providing the reflecting element 48 and the reflecting plate 27 on the back surface of the radiating element 11B. it can. Further, the configuration of the radiating element 11B and the reflecting element 48 can be simplified.

(10th Embodiment)
Next, a broadband antenna with a reflector according to a tenth embodiment of the present invention will be described.

  FIG. 15: is a front view which shows the structure of the radiation | emission element 11 part of the broadband antenna with a reflector which concerns on 10th Embodiment of this invention.

  The reflector-equipped wideband antenna according to the tenth embodiment includes four corners of the first and second antenna elements 12a and 12b constituting the radiating element 11 in the first embodiment shown in FIGS. As shown in FIG. 15, notches 51a to 51d are provided by cutting out the connecting portion between the linear element 14 and the side element 15 as shown in FIG. The notches 51a to 51d are set in a range where the width L11 is about 0.01 to 0.08λ (5 to 40 mm) and the height H11 is about 0.01 to 0.16λ (5 to 80 mm). Since other configurations are the same as those of the reflector-equipped broadband antenna 10A according to the first embodiment, the same portions are denoted by the same reference numerals, and detailed description thereof is omitted. Moreover, since the reflective element 21 provided on the back side of the radiating element 11 has the same configuration as that of the first embodiment, detailed description thereof is omitted, but the radiating element 11 provided with the notches 51a to 51d is omitted. It is desirable to form the reflective element 21 in accordance with the shape.

  FIG. 16 shows that the feeding point impedance of the reflector-equipped broadband antenna using the radiating element 11 according to the tenth embodiment is 75Ω (unbalanced), and the width L11 of the notches 51a to 51d is 0.08λ (40 mm). This is a VSWR characteristic when the height H11 is set to 0.16λ (80 mm). The horizontal axis represents frequency (MHz), and the vertical axis represents VSWR (voltage standing wave ratio). The dimensions of the other parts are the same as in the first embodiment, and are based on 620 MHz (λ = 484 mm).

  As is clear from FIG. 16, the reflector-equipped wideband antenna according to the tenth embodiment has a frequency band of 470 to 950 MHz wider than 470 to 770 MHz of terrestrial digital TV broadcasting when the feeding point impedance is set to 75Ω. VSWR could be 2.5 or less. Moreover, the specific band at VSWR 2.5 or less was about 62%, and a very wide band characteristic was obtained, and the band characteristic could be improved particularly in a high band. Accordingly, the reflector-equipped wide-band antenna according to the tenth embodiment is not limited to terrestrial digital TV broadcasting using a frequency band of 470 to 770 MHz, but also terrestrial digital TV broadcasting using a wider frequency band. It can be applied to the above.

  In the tenth embodiment, in the first embodiment, the corners of the first and second antenna elements 12a and 12b constituting the radiating element 11, that is, the connection portions between the linear elements 14 and the side elements 15 are used. Although the case where the notches 51a to 51d are provided has been described, in addition, in the second to sixth embodiments, each corner portion (straight line) of the first and second antenna elements 12a and 12b constituting the radiating element 11 is described. Notch portions 51a to 51d may be provided in the connection portion between the shape element 14 and the side element 15. In the second to sixth embodiments, even when the notches 51a to 51d are provided at the corners of the first and second antenna elements 12a and 12b, the height is the same as in the tenth embodiment. The band characteristics in the band can be improved.

  Further, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements without departing from the scope of the invention in the implementation stage.

The structure of the broadband antenna with a reflector which concerns on 1st Embodiment of this invention is shown, (a) is a front view, (b) is a right view, (c) is a lower side view. It is a front view of the radiation element in the embodiment. It is a front view of the reflective element in the embodiment. It is a VSWR characteristic figure of the broadband antenna with a reflector concerning the embodiment. It is a figure for demonstrating the example of various dimension settings of the radiation element in the embodiment. The structure of the broadband antenna with a reflector which concerns on 2nd Embodiment of this invention is shown, (a) is a front view, (b) is a right view, (c) is a lower side view. The structure of the broadband antenna with a reflector which concerns on 3rd Embodiment of this invention is shown, (a) is a front view, (b) is a right view, (c) is a lower side view. The structure of the broadband antenna with a reflector which concerns on 4th Embodiment of this invention is shown, (a) is a front view, (b) is a right view, (c) is a bottom view. The structure of the broadband antenna with a reflector which concerns on 5th Embodiment of this invention is shown, (a) is a front view, (b) is a right view, (c) is a bottom view. It is a gain characteristic figure of the broadband antenna with a reflector concerning the embodiment. The structure of the broadband antenna with a reflector which concerns on 6th Embodiment of this invention is shown, (a) is a front view, (b) is a right view, (c) is a lower side view. The structure of the broadband antenna with a reflector which concerns on 7th Embodiment of this invention is shown, (a) is a front view, (b) is a right view, (c) is a lower side view. The structure of the broadband antenna with a reflector which concerns on 8th Embodiment of this invention is shown, (a) is a front view, (b) is a right view, (c) is a lower side view. The structure of the radiating element and reflective element of the broadband antenna with a reflector which concerns on 9th Embodiment of this invention is shown, (a) is a front view of a radiating element, (b) is a front view of a reflective element. It is a front view which shows the structure of the radiation element of the broadband antenna with a reflector which concerns on 10th Embodiment of this invention. It is a VSWR characteristic figure of the broadband antenna with a reflector concerning the embodiment.

Explanation of symbols

  10A to 10H: a broadband antenna with reflectors according to the first to eighth embodiments, 11, 11A, 11B ... radiating elements, 12a, 12b ... first and second antenna elements, 13 ... coupling line, 14 ... Linear element, 15 ... side element, 16 ... groove, 17a, 17b ... feeding convex part, 18a, 18b ... feeding point, 19 ... bent part, 20a, 20b ... gap part, 21 ... reflecting element, 22a, 22b ... Loop reflector, 25 ... Reflector, 26 ... Bent part, 27 ... Reflector, 28 ... Bent part, 31, 31A ... Cover, 32 ... Mounting bracket, 33 ... Feeding terminal, 34 ... Feeding line, 36 ... Holding member, 41a, 41b ... Loop element, 42 ... Feed line, 44, 45 ... Dipole stack, 46 ... Feed line, 48 ... Reflective element, 49a, 49b ... Linear element, 49a, 49b ... Linear element, 51a ~ 51d ... Cut-out portion.

Claims (8)

A radiating element, and a reflector disposed at a predetermined interval on the back surface of the radiating element,
The radiating elements are arranged at predetermined intervals in the vertical direction within the same plane by a plate-like conductive member, and are formed at both ends of the linear elements formed on both outer sides in the vertical direction. First and second antenna elements comprising the formed side elements, a coupling line coupling between the side elements of the first antenna element and the side elements of the second antenna element, and the coupling line And a feeding point provided at substantially the center of the
The coupling line is formed such that a width of the feeding point portion is narrower than a width between side elements of the first and second antenna elements, and each side portion of the first and second antennas from the vicinity of the feeding point. A broadband antenna with a reflector, wherein the antenna is inclined toward the element.   The wideband antenna with a reflector according to claim 1, wherein a distance between the radiating element and the reflector is set in a range of about 0.125 to 0.135λ.   The broadband antenna with a reflector according to claim 1, wherein the coupling line is formed wider as it approaches a feeding point. A radiating element, a reflector disposed behind the radiating element at a distance of about 0.25λ, and between the radiating element and the reflecting plate, about 0.125 to 0.135λ from the radiating element. And a reflective element composed of linear elements arranged with an interval of
The radiating elements are arranged at predetermined intervals in the vertical direction within the same plane by a plate-like conductive member, and are formed at both ends of the linear elements formed on both outer sides in the vertical direction. First and second antenna elements comprising the formed side elements, a coupling line coupling between the side elements of the first antenna element and the side elements of the second antenna element, and the coupling line A wideband antenna with a reflector, comprising a feeding point provided at a substantially central portion of the reflector. 5. The wideband antenna with a reflector according to claim 1, wherein a width of the side element is set to about 1 to 1.5 times a width of the linear element. The broadband antenna with a reflector according to any one of claims 1 to 5, wherein the first and second antenna elements are formed by notching a connection portion between a linear element and a side element.   7. The broadband with a reflector according to claim 1, wherein a width of the side element and a width of the linear element are set so that a feeding point impedance at the feeding point is about 75Ω. antenna. A radiating element, and a reflector disposed at a predetermined interval on the back surface of the radiating element,
The radiating elements are arranged at predetermined intervals in the vertical direction within the same plane by a plate-like conductive member, and are formed at both ends of the horizontal elongated elements formed on both outer sides in the vertical direction. First and second antenna elements comprising the formed side elements, a coupling line coupling between the side elements of the first antenna element and the side elements of the second antenna element, and the coupling line And a feeding point provided at substantially the center of the
The coupling line is formed so that the width of the feeding point portion is narrower than the width between the side elements of the first and second antenna elements, and each side portion of the first and second antennas from the vicinity of the feeding point. Inclined toward the element, and
A distance between the radiating element and the reflector is set in a range of about 0.125 to 0.135λ;
A broadband antenna with a reflector, wherein the coupling line is formed wider as it approaches a feeding point.

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