JP2009278540A - Balun device and antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a balun device including a pattern that is produced not only from a printed circuit board but also from a metal plate, and an antenna device with the balun device. <P>SOLUTION: The balun device 1 includes lead wire parts 11, 12, a plurality of stubs 13, 14 and winding parts 15, 16. The lead wire part 11, the plurality of stabs 13 and the winding part 15 are formed integrally. Similarly, the lead wire part 12, the plurality of stabs 14 and the winding part 16 are integrally formed. One end of a parallel line constituted of the lead wire parts 11, 12 is connected to a dipole antenna and another end of the parallel line is connected to a coaxial cable. The balun device 1 is formed from a printed circuit board, wherein the winding parts 15, 16 are folded twice to avoid complication of a pattern of the winding parts. Therefore, the balun device 1 is easily formed not only from the printed circuit board but also from a metal plate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a balun device that mutually converts unbalanced feeding and balanced feeding, and an antenna device including the balun device.

  The balun is used for connecting, for example, a dipole antenna and a coaxial cable. When an unbalanced feed cable such as a coaxial cable is directly connected to a balanced antenna such as a dipole antenna, the outer conductor of the coaxial cable (generally braided thin copper wire called a braided wire) Leakage current occurs and the original operation of each is hindered. Such a problem can be avoided by connecting the balanced antenna and the coaxial cable through the balun.

For example, as disclosed in Japanese Patent Laid-Open No. 2006-14157 (Patent Document 1) and Japanese Patent Laid-Open No. 6-188610 (Patent Document 2), it has been proposed to form the balun using a printed circuit board. Japanese Utility Model Laid-Open No. 62-98213 (Patent Document 3) discloses a spiral printed pattern as a conductor pattern formed on a printed circuit board.
JP 2006-14157 A JP-A-6-188610 Japanese Utility Model Publication No. 62-98213

  In the conventional balun using a printed circuit board, in many cases, not only the width of the strip line is narrow, but also the pattern formed by the strip line is complicated. For example, a spiral pattern as disclosed in Japanese Utility Model Publication No. 62-98213 may be included in a balun on a printed circuit board.

  On the other hand, for reasons such as manufacturing cost, it is conceivable to form a pattern similar to the pattern formed on the printed board by pressing a metal plate. In this case, it is necessary to form a pattern similar to the pattern formed on the printed board on the press die. However, the more complicated the pattern is, the more difficult it is to create a mold and the higher the possibility that the pattern cannot be reproduced with a metal plate. For these reasons, it is not easy to form a conventional balun formed on a printed circuit board using a metal plate.

  The objective of this invention is providing the balun apparatus which has a pattern which can be produced not only with a printed circuit board but with a metal plate, and an antenna apparatus provided with the balun apparatus.

  In summary, the present invention is a balun device that includes planar first and second conducting wire portions, at least one stub, a first winding portion, and a second winding portion. The first and second conducting wire portions are arranged in parallel to each other. At least one stub is disposed between the first and second conductor portions, and has one end connected to one of the first and second conductor portions and the other end electrically opened. Including. The first winding portion is disposed between the first and second conductive wire portions, the extending direction of the first and second conductive wire portions is defined as the first direction, and the first and second conductive wire portions are arranged in the first direction. Assuming that the arrangement direction is the second direction, it is formed so as to extend in the second direction from the first conductor portion and bend alternately in the first and second directions. The second winding portion is disposed between the first and second conducting wire portions, and the second winding portion extends from the second conducting wire portion so that the tip thereof is located in a region surrounded by the first winding portion. It is formed so as to extend in the direction and bend alternately in the first and second directions.

  Preferably, the at least one stub is a first stub disposed at a location relatively close to the first and second winding portions, and the first stub with respect to the first and second winding portions. A plurality of stubs including a second stub disposed at a relatively far place.

More preferably, the plurality of stubs are alternately connected to the first and second conductor portions.
More preferably, the first and second conducting wire portions, at least one stub, and the first and second winding portions are integrally formed by a substantially planar conductor.

  According to another aspect of the present invention, there is provided an antenna device, which has any one of the balun devices described above, and first and second feeding parts, and is formed integrally with the balun device. With. An end portion of the first conductor portion located on the side far from the first winding portion is connected to the first power feeding portion. An end portion of the second conductor portion located on the side far from the second winding portion is connected to the second power feeding portion.

  ADVANTAGE OF THE INVENTION According to this invention, the balun apparatus which has a pattern which can be produced not only with a printed circuit board but with a metal plate is realizable.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a diagram showing a balun device 1 according to the present embodiment. FIG. 1A is a plan view of the balun device 1.

  Referring to FIG. 1A, the balun device 1 includes conductor portions 11 and 12, a plurality of stubs 13 and 14, and winding portions 15 and 16. The conducting wire part 11, the plurality of stubs 13, and the winding part 15 are integrally formed. Similarly, the conductor portion 12, the plurality of stubs 14, and the winding portion 16 are integrally formed.

  The balun device 1 according to the present embodiment is produced, for example, by pressing a metal plate. Note that the balun device 1 may be formed at one time, a plate-like conductor in which the conductor portion 11, the plurality of stubs 13, and the winding portion 15 are integrated, the conductor portion 12, the plurality of stubs 14, and the winding. The balun device 1 may be formed by separately forming a plate-like conductor integrated with the portion 16 and combining them.

  In the present embodiment, an element of the balun device 1 that substantially functions as a line even if it is a plate-like conductor or a thin-film conductor is referred to as a “conductor portion” or a “linear conductor”.

  The conducting wire portions 11 and 12 are formed in an elongated rectangular shape and are arranged in parallel. Thereby, the conducting wire parts 11 and 12 constitute a parallel line. The X direction shown in FIG. 1 is the extending direction of the conducting wire portions 11 and 12, and the Y direction is the arrangement direction of the conducting wire portions 11 and 12, and is a direction perpendicular to the X direction.

  Further, in FIG. 1, one end and the other end of the parallel line constituted by the conducting wire portions 11 and 12 are respectively indicated as “A end” and “B end”. When the balun device 1 is interposed between the dipole antenna and the coaxial cable, the A end is connected to the dipole antenna and the B end is connected to the coaxial cable.

  Here, the impedance of the dipole antenna is generally about 300Ω, and the impedance of the coaxial cable is generally about 75Ω. Therefore, the balun device 1 is configured so that the impedance on the A-end side is about 300Ω and the impedance on the B-end side is about 75Ω (that is, as a balun with an impedance conversion ratio of 4: 1). Specifically, such a configuration is realized by arranging the plurality of stubs 13 and 14 and the winding portions 15 and 16 between the conductor portions 11 and 12.

  The plurality of stubs 13 and 14 are conductive wire portions extending in the Y direction. One end of each of the plurality of stubs 13 is connected to the conductor portion 11. The other end (tip) of each of the plurality of stubs 13 is electrically opened without contacting the conductor portion 12. Similarly, one end of each of the plurality of stubs 14 is connected to the conductor portion 12. The other end (tip) of each of the plurality of stubs 14 is electrically opened without contacting the conductor portion 11.

  In the region 2 that is a location relatively close to the winding portions 15 and 16, three stubs (two stubs 13 and one stub 14) are arranged, and a location (region) that is relatively far from the winding portions 15 and 16. In a region 3 that is closer to the A end than 2), two stubs (stub 13 and stub 14 adjacent thereto) are arranged. As described above, in the present embodiment, at least one stub is disposed in the region 2 relatively close to the winding portions 15 and 16, and the region 3 relatively far from the winding portions 15 and 16 than the stub. At least one stub. In the present embodiment, the region 2 which is a location relatively close to the winding portions 15 and 16 is a location close to the winding portion 15 and a location relatively far from the winding portions 15 and 16. A certain region 3 is a substantially central portion of the conducting wire portion 11 (and the conducting wire portion 12).

  By connecting the stub to the conductive wire portions 11 and 12, the impedance of the parallel line composed of the conductive wire portions 11 and 12 can be reduced. However, since the distance between the conductor portions 11 and 12 is adjusted so that the impedance at the A end is about 300Ω, when many stubs are connected to the side close to the A end, the impedance at the A end is about 300Ω. Can deviate significantly from Therefore, when a dipole antenna is connected to the A end, for example, VSWR (voltage standing wave ratio) may increase. The VSWR is a numerical value indicating the relationship between the traveling wave and the reflected wave in the AC transmission path, and the smaller the value, the better the antenna performance. In order to reduce the VSWR, the impedance at the A end needs to be close to 300Ω.

  In the present embodiment, the stubs 13 and 14 are arranged in the region 2 adjacent to the winding part 15 and the region 3 which is a substantially central part of the conducting wire part 11 (and the conducting wire part 12). As a result, the impedance at the A end can be maintained at about 300Ω, so that the VSWR (voltage standing wave ratio) of the antenna connected to the A end can be reduced. Further, by connecting an appropriate number of stubs at a location relatively close to the winding portion 15, the impedance at the B end can be brought close to a predetermined impedance (approximately 75Ω). Furthermore, the impedance at the B end can be adjusted to the predetermined impedance by the stub 13 (14) provided in the region 3 farther from the winding parts 15 and 16 than the region 2.

  The stubs 13 and 14 are alternately arranged along the X direction. That is, the plurality of stubs are alternately connected to the conductor portions 11 and 12. As a result, it is possible to prevent the balanced power supply mode by the parallel lines (conducting wire portions 11 and 12) from collapsing, so that when a dipole antenna is connected to the A end, the operation of the antenna can be stabilized.

  Winding portions 15 and 16 are arranged between conductive wire portions 11 and 12. Winding portion 15 is formed to extend in the Y direction from conductive wire portion 11 and bend alternately in the X direction and the Y direction. The winding portion 16 is formed so as to extend from the conducting wire portion 12 in the Y direction and bend alternately in the X direction and the Y direction. Furthermore, the tip of the winding part 16 is located in a region surrounded by the winding part 15.

  That is, when the balun device 1 is viewed in plan as shown in FIG. 1A, the winding direction of the winding portion 15 and the winding direction of the winding portion 16 are opposite to each other. They are arranged to engage with each other.

  Moreover, in this Embodiment, the frequency | count of bending of the coil parts 15 and 16 is 2 times. Thereby, since it can avoid that the pattern of a winding part becomes complicated, the balun apparatus 1 can be easily formed with a metal plate.

  Next, the dimension of the balun apparatus 1 which concerns on this Embodiment is demonstrated. In addition, the numerical value shown below is an example, Comprising: It clearly describes that the balun apparatus 1 is not limited by the following dimension.

  The length of the lead wire portions 11 and 12 in the X direction is about 150 mm. However, the length in the X direction of the conducting wire portions 11 and 12 may be about 70 to 80 mm.

  The line width of each of the conducting wire portions 11 and 12 is about 3 mm. The space | interval (distance of the Y direction from the conducting wire part 11 to the conducting wire part 12) of the conducting wire parts 11 and 12 is about 12 mm. In addition, the space | interval of conducting wire part 11 and 12 should just be determined so that the impedance in the A end of the parallel line comprised by conducting wire part 11 and 12 may be set to about 300 (ohm).

  The line width of each of the plurality of stubs 13 and 14 and the line width of each of the winding portions 15 and 16 are also about 3 mm. In addition, the space | interval of the stub 13 and the stub 14, and the space | interval of the coil | winding parts 15 and 16 are not specifically limited. For example, if the balun device 1 is formed at a time by pressing a single metal plate, the above-described interval may be larger than the minimum interval at which the metal plate can be punched by a mold.

  In the region 2, the distance from the stub 13 located farthest from the winding portion 15 to the stub 14 in the region 3 is about 31 mm.

  Moreover, in this Embodiment, the shortest distance from the B end of the parallel line comprised from the conducting wire parts 11 and 12 to the coil | winding part 16 is about 7 mm. However, this shortest distance may be a value within a range of about 3 to 10 mm.

  If the impedance at the B end is set to 75Ω by adjusting the distance between the conductor portions 11 and 12 constituting the parallel line, the distance is about 1 mm. However, the distance between the conductive wire portions 11 and 12 is adjusted so that the impedance at the A end is about 300Ω, and is about 12 mm in the present embodiment. By reducing the shortest distance from the B end to the winding portion 16, the impedance at the B end can be maintained at about 75Ω even if the distance between the conductor portions 11 and 12 at the B end is about 12 mm. Further, by reducing this distance, it is possible to avoid an increase in loss near the B end.

  FIG. 1B is a side view of the balun device 1 from the direction of arrow A1 shown in FIG. With reference to FIG. 1 (B), the thickness of the metal plate which comprises the balun apparatus 1 is about 1 mm.

  The balun device 1 according to the present embodiment is not limited to being formed of a metal plate. As shown in FIG. 2, the balun device 1 can also be formed of a printed board.

  FIG. 2A is a plan view of the balun device 1 formed of a printed circuit board. FIG. 2B is a side view of the balun device 1 from the direction of the arrow A2 shown in FIG. The planar pattern shown in FIG. 2A is the same as the planar pattern shown in FIG. However, according to the configuration shown in FIG. 2, the balun device 1 is formed by a thin film conductor on the main surface of the dielectric substrate 20. As shown in FIG. 2B, the thickness of the thin film conductor is smaller than the thickness of the dielectric substrate 20. That is, the balun device 1 shown in FIG. 2 is thinner than the balun device 1 shown in FIG.

  According to the present embodiment, since the balun device 1 can be made of a metal plate or a printed board, the balun device can be thinned.

  FIG. 3 is a diagram showing a configuration of a balun device 1A that is considered to be general. FIG. 3A is an image diagram of the balun device 1A. FIG. 3B is an equivalent circuit diagram of the balun device 1A shown in FIG.

  Referring to FIGS. 3A and 3B, balun device 1A includes a glasses core 25 and a pair of insulated conductors 26 and 27. The insulated conductors 26 and 27 are wound around the eyeglass core 25. One end of the insulated conducting wire 27 is connected to the terminal 23 on the antenna side, and the other end of the insulated conducting wire 27 is connected to the terminal 28 on the coaxial cable side. One end of the insulated conductor 26 is connected to the terminal 24 on the antenna side, and the other end of the insulated conductor 26 is connected to the terminal 29 on the coaxial cable side.

  The thickness of the eyeglass core 25 (the length in the direction passing through the paper surface of the eyeglass core 25 shown in FIG. 3A) is, for example, about 3 to 4 mm. On the other hand, according to the present embodiment, since the balun device can be manufactured using a metal plate or a printed board, the balun device can be thinned.

  Moreover, when manufacturing the balun apparatus 1A shown in FIG. 3, the process for winding the insulated conducting wires 26 and 27 around the spectacles core 25 is required. However, according to the present embodiment, the balun device 1 has the winding portions 15 and 16 formed in a plane instead of the insulated conductors 26 and 27. Winding portions 15 and 16 are formed integrally with conductive wire portions 11 and 12, respectively. Therefore, in this embodiment, a process for winding the insulated lead wire around the eyeglass core is not necessary. Thereby, according to this Embodiment, the manufacturing cost of a balun apparatus can be reduced.

  Further, even if a plurality of balun devices 1A are manufactured by the same manufacturing method, there is a possibility that the performance variation between them increases depending on the difference in how the insulated conductors are wound. According to the present embodiment, for example, a balun device can be manufactured by pressing a metal plate, so that each element (conducting wire portions 11 and 12, stubs 13 and 14 and winding portion 15 constituting the balun device 1 is formed. , 16) can be reduced. Therefore, according to the present embodiment, it is possible to reduce the variation in performance among the plurality of balun devices 1.

  FIG. 4 is a diagram illustrating a state in which the balun device 1 is connected to a dipole antenna and a coaxial cable. Referring to FIG. 4, a folded dipole antenna 31 is connected to the A end of the parallel line composed of the conductive wire portions 11 and 12.

  In general, in a dipole antenna, two feeding parts (feeding points) are provided at a distance from each other. The folded dipole antenna 31 includes power feeding portions FD1 and FD2. The folded dipole antenna 31 is formed integrally with the conductor portions 11 and 12 such that the power feeding portions FD1 and FD2 are connected to the conductor portions 11 and 12, respectively.

  On the other hand, a coaxial cable 32 is connected to the B end side of the parallel line. The coaxial cable 32 has an outer conductor 33 and an inner conductor 34. The outer conductor 33 and the inner conductor 34 are connected to the conductor portions 11 and 12, respectively.

  The balun device 1 shown in FIG. 4 is made of a metal plate, but may be made of a printed board. Also in this case, the folded dipole antenna 31 can be formed integrally with the conductor portions 11 and 12 so that the power feeding portions FD1 and FD2 are connected to the conductor portions 11 and 12, respectively.

  As described above, according to the present embodiment, the balun device 1 can be manufactured using a metal plate or a printed circuit board, so that the antenna and the balun device 1 can be manufactured integrally. As a result, the number of parts of the antenna device including the antenna and the balun device 1 can be reduced, so that the manufacturing cost of the antenna device can be reduced.

  In addition, when punching a metal plate with a metal mold | die, it can be anticipated that manufacturing cost becomes lower than the case where the thin film conductor on a dielectric substrate is patterned. That is, when the balun device 1 is manufactured using a metal plate, the manufacturing cost can be reduced as compared with the case where the balun device 1 is manufactured using a printed board.

  In FIG. 4, a folded dipole antenna is shown as an example of a dipole antenna connected to the balun device 1. However, the dipole antenna connected to the balun device 1 is not limited to the folded dipole antenna. For example, a linear dipole antenna, a fan A (fan-shaped) dipole antenna or the like may be used.

  Next, the stubs 13 and 14 and the winding portions 15 and 16 included in the balun device 1 according to the present embodiment will be described in more detail.

  FIG. 5 is a schematic diagram showing a partial configuration of the balun device 1A reproduced by a printed circuit board. Referring to FIG. 5, winding portions 15A and 16A are formed on the surface of dielectric substrate 20 by strip lines. The winding portions 15A and 16A are obtained by reproducing the insulated conductors 26 and 27 wound around the eyeglass core 25 shown in FIG. According to this configuration, in order to obtain the same characteristics as the balun device 1A, it is necessary to increase the number of windings of the winding portions 15A and 16A as much as possible. However, in order to prevent an increase in the size of the dielectric substrate 20 (an increase in the area of the main surface), in the configuration shown in FIG. 5, the width of the strip line is reduced and the interval between the winding portions 15A and 16A is reduced. Need to be small.

  The pattern shown in FIG. 5 can be realized on a printed circuit board. However, if this pattern is formed by a metal plate, a mold pattern for press working becomes complicated. For this reason, the punching of the metal plate becomes insufficient, and for example, in the processed metal plate, there is a possibility that a problem that originally separated wires are connected to each other may occur. That is, in order to form a balun device with a metal plate, the simpler the pattern, the better.

  FIG. 6 is a diagram for explaining the stubs 13 and 14 and the winding portions 15 and 16 included in the balun device 1 according to the present embodiment. Referring to FIGS. 6 and 5, balun device 1 according to the present embodiment has stubs 13 and 14 in which a part of winding portions 15A and 16A shown in FIG. It has the structure replaced by. Therefore, the number of turns of the winding parts 15 and 16 can be made smaller than the number of turns of the winding parts 15A and 16A shown in FIG.

  As described above, the winding portion 15 is formed to extend in the Y direction from the conductor portion 11 and bend alternately in the X direction and the Y direction. The winding portion 16 is formed so as to extend from the conducting wire portion 12 in the Y direction and bend alternately in the X direction and the Y direction. That is, the number of times of bending of each of the winding portions 15 and 16 is only two.

  Specifically, the winding portion 15 includes linear conductors 41 to 43. One end of the linear conductor 41 is connected to the conducting wire portion 11, and the linear conductor 41 extends in the Y direction. One end of the linear conductor 42 is connected to the other end (tip) of the linear conductor 41, and the linear conductor 42 extends in the Y direction. One end of the linear conductor 43 is connected to the other end (tip) of the linear conductor 42, and the linear conductor 43 extends in the X direction so that the other end faces the conductor portion 11.

  Similarly, the winding portion 16 includes linear conductors 44 to 46. The linear conductor 44 is located on the opposite side of the linear conductor 41 with respect to the linear conductor 43. One end of the linear conductor 44 is connected to the conductor portion 12, and the linear conductor 44 extends in the Y direction. One end of the linear conductor 45 is connected to the other end (tip) of the linear conductor 44, and the linear conductor 45 extends in the X direction so as not to be in contact with the linear conductor 41. One end of the linear conductor 46 is connected to the other end (tip) of the linear conductor 45, and the linear conductor 46 extends in the Y direction so that the other end (tip) faces the conductor portion 12. The front end of the linear conductor 46 is surrounded by the linear conductors 41 to 43.

  By forming the winding portions 15 and 16 in this manner, a simplified pattern can be realized as compared with the pattern shown in FIG. This makes it possible to form the balun device 1 from a metal plate.

  The number of stubs 13 and 14 is not limited as shown in FIG. FIG. 7 is a diagram showing a first modification of the balun device according to the present embodiment. Referring to FIG. 7, three stubs 13 and three stubs 14 are arranged in region 2, which is a place near winding portions 15 and 16. On the other hand, one stub 13 and one stub 14 are arranged in the region 3 that is far from the winding portions 15 and 16. Thus, the number of stubs 13 and 14 is not particularly limited.

  Note that the number of stubs may be one as long as impedance matching can be realized. However, from the viewpoint of stabilizing the operation of the dipole antenna connected to the balun device 1, it is preferable to arrange the stubs 13 and 14 alternately along the X direction.

  Further, the shapes of the winding portions 15 and 16 are not limited as shown in FIG. FIG. 8 is a diagram showing a second modification of the balun device according to the present embodiment. Referring to FIG. 8, in this modification, the number of windings 15 and 16 is three. When the balun device 1 is manufactured from a metal plate or when the balun device 1 is manufactured from a printed circuit board, the line width of the winding portions 15 and 16 and / or the interval between the winding portions 15 and 16 can be reduced. If so, the number of bendings of the winding portions 15 and 16 may be increased in this way.

  Subsequently, VSWR and passage loss will be described as characteristics of the balun device 1 according to the present embodiment.

  FIG. 9 is a diagram showing frequency characteristics of VSWR of the balun device 1 according to the present embodiment. Referring to FIG. 9, VSWR is maintained at 1.5 or less over a range of about 470 MHz to about 770 MHz. This frequency range corresponds to the band of UHF (Ultra High Frequency) television broadcasting in Japan. The frequency band of terrestrial digital broadcasting in Japan is in the range of about 470 MHz to about 710 MHz. The results shown in FIG. 9 indicate that the balun device 1 has a practical level of VSWR.

  The frequency characteristics of the VSWR were measured by connecting a terminal resistor of about 300Ω to the A end of the parallel line of the balun device 1 and connecting an F-type plug to the B end of the parallel line.

  FIG. 10 is a diagram showing the frequency characteristics of the passage loss of the balun device 1 according to the present embodiment. The frequency range is the same as the range shown in FIG. Further, the smaller the absolute value of the passage loss, the better the performance of the balun device. Referring to FIG. 10, in the range of about 470 MHz to about 620 MHz, the pass loss is approximately in the range of −0.3 to −0.5 (dB), and in the range of about 620 to about 680 MHz, the pass loss is , Approximately in the range of −0.5 to −1 (dB), and in the range of about 680 to about 770 MHz, the passing loss is approximately in the range of −1 to −2 (dB). The frequency range of about 470 MHz to about 620 MHz corresponds to the low channel band of terrestrial digital broadcasting in Japan. The results shown in FIG. 10 indicate that the balun device 1 has a practical level of passage loss.

  The frequency characteristics of the passage loss were measured by preparing two balun devices 1 and connecting the A ends of the two balun devices 1 to each other. The result shown in FIG. 10 is a half of the measured value.

  As described above, the balun device 1 according to the present embodiment is excellent in performance in the UHF television broadcast band of Japan (particularly the terrestrial digital broadcast band). Therefore, the balun device 1 can be used to connect the UHF television broadcast receiving antenna (including the terrestrial digital broadcast receiving antenna) and the coaxial cable.

  FIG. 11 is a diagram showing the frequency characteristics of the passage loss of the balun device 1A shown in FIG. The frequency range is the same as the range shown in FIG. Referring to FIG. 11, in the range of about 470 MHz to about 620 MHz, the pass loss is generally in the range of −0.4 to −0.6 (dB), and in the range of about 620 to about 680 MHz, the pass loss is , Approximately in the range of −0.6 to −0.7 (dB), and in the range of approximately 680 to approximately 770 MHz, the pass loss is approximately in the range of −0.7 to −1 (dB).

  Comparing FIG. 10 and FIG. 11, in the range of about 470 MHz to about 680 MHz, the passing loss of the balun device 1 is almost the same as the passing loss of the balun device 1A. From this, it can be seen that the balun device 1 has almost the same performance as the balun device considered to be general in the band of Japanese UHF television broadcasting (particularly the band of terrestrial digital broadcasting).

  In the above description, the balun device 1 according to this embodiment is assumed to perform 4: 1 impedance conversion (conversion between 300Ω and 75Ω). However, the balun device 1 according to the present embodiment performs, for example, 2: 1 impedance conversion (for example, conversion between 150Ω and 75Ω) by appropriately determining the interval between the parallel lines (conductor portions 11 and 12). It is also possible to apply as a balun device to be performed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a figure which shows the balun apparatus 1 which concerns on this Embodiment. It is a figure which shows the balun apparatus 1 which concerns on this Embodiment formed with the printed circuit board. It is a figure which shows the structure of 1 A of balun apparatuses considered to be general. It is a figure which shows the state which connected the balun apparatus 1 to the dipole antenna and the coaxial cable. It is a schematic diagram which shows the structure of a part of 1 A of balun apparatuses reproduced with the printed circuit board. It is a figure explaining the stubs 13 and 14 and the coil | winding parts 15 and 16 which are contained in the balun apparatus 1 which concerns on this Embodiment. It is a figure which shows the 1st modification of the balun apparatus which concerns on this Embodiment. It is a figure which shows the 2nd modification of the balun apparatus which concerns on this Embodiment. It is a figure which shows the frequency characteristic of VSWR of the balun apparatus 1 which concerns on this Embodiment. It is a figure which shows the frequency characteristic of the passage loss of the balun apparatus 1 which concerns on this Embodiment. It is the figure which showed the frequency characteristic of the passage loss of 1 A of balun apparatuses shown in FIG.

Explanation of symbols

  1, 1A balun device, 2, 3 region, 11, 12 conductor part, 13, 14 stub, 15, 16, 15A, 16A winding part, 20 dielectric substrate, 23, 24, 28, 29 terminal, 25 glasses core, 26, 27 Insulated conductor, 31 Dipole antenna, 32 Coaxial cable, 33 Outer conductor, 34 Inner conductor, 41-46 Linear conductor, A1, A2 arrow, FD1, FD2 Feeding part.

Claims (5)

First and second conductive wire portions arranged in parallel to each other and planar,
At least 1 including one end disposed between the first and second conducting wire portions and connected to one of the first and second conducting wire portions and the other end electrically open; Two stubs,
It arrange | positions between the said 1st and 2nd conducting wire part, the extension direction of the said 1st and 2nd conducting wire part is made into the 1st direction, and the arrangement direction of the said 1st and 2nd conducting wire part is 2nd A first winding portion that extends from the first conductor portion in the second direction and is bent alternately in the first and second directions;
Extending from the second conductor portion in the second direction so that the tip is located in a region disposed between the first and second conductor portions and surrounded by the first winding portion; and And a second winding part formed to bend alternately in the first and second directions.   The at least one stub includes a first stub disposed at a location relatively close to the first and second winding portions, and the first stub with respect to the first and second winding portions. The balun device according to claim 1, wherein the balun device is a plurality of stubs including a second stub disposed at a relatively far place.   The balun device according to claim 2, wherein the plurality of stubs are alternately connected to the first and second conductor portions.   The first and second conductor portions, the at least one stub, and the first and second winding portions are integrally formed by a substantially planar conductor. 4. The balun device according to any one of items 3. A balun device according to any one of claims 1 to 4,
An antenna main body having first and second power feeding sections and formed integrally with the balun device;
The end portion of the first conductor portion located on the side far from the first winding portion is connected to the first power feeding portion,
An antenna device, wherein an end portion of a second conductor portion located on a side far from the second winding portion is connected to the second power feeding portion.

Images