JP3194030B2 - TV wave reflection suppression antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna for suppressing reflection of a television wave, and more particularly to an antenna installed on the outer wall of a structure in order to reduce a reception disturbance such as a ghost (multiple image) caused by the reflection of the TV wave from the outer wall of the structure. The present invention relates to an antenna for suppressing reflection of television waves.

[0002]

2. Description of the Related Art When a direct wave from a transmitting antenna of a television wave and a reflected wave from the outer wall surface of a structure such as a reinforced building arrive at a receiving antenna together, a ghost ( Reception failure such as multiple images) occurs. In order to reduce such a reception obstacle, it is necessary to take measures such as avoiding reception of the reflected wave on the receiving antenna side or suppressing radio wave reflection on the outer wall surface of the structure. As a conventional method of suppressing radio wave reflection on the outer wall surface of the structure, a wire mesh is provided by inclining the outer wall surface of the structure on the TV wave arrival side upward so that the incoming TV radio wave is reflected toward the sky, A method of suppressing reflection toward the receiving antenna has been implemented. In recent years, structures such as high-rise buildings have adopted a block wall in which radio wave absorbing ferrite is embedded in advance on the outer wall surface on the radio wave arrival side, and a method of suppressing the reflection of television radio waves by absorbing the radio wave of the ferrite has been performed. .

[0003]

However, a conventional method of suppressing radio wave reflection by a wire mesh provided on the outer wall of a structure is as follows.
There is a problem that the aesthetic appearance of the structure is impaired and that wind noise is generated when the wind is strong. On the other hand, the method of suppressing radio wave reflection by radio wave absorbing ferrite embedded on the outer wall of the structure is:
Although it does not impair the aesthetics of the structure, there is a problem that the cost required for suppressing radio wave reflection per unit area is much higher than other methods.

An object of the present invention is to provide an antenna for suppressing reflection of television radio waves, which is inexpensive and does not impair the aesthetics of the structure.

[0005]

SUMMARY OF THE INVENTION The present inventor has focused on a method of receiving television waves with an appropriate antenna and suppressing the reflection by consuming the power of the television waves, and experimentally produced various antennas. As a result, we paid particular attention to a zigzag antenna in which both sides of the feed point of the antenna conductor were bent into waveforms. Conventionally, zigzag antennas are rarely used as television transmitting antennas, and FIG. 5 shows an example thereof. The zigzag antenna 13 shown in FIG. 5 has a metal reflecting plate 9 and a zigzag antenna conductor 12 that is held from the metal reflecting plate 9 with a gap of 0.1 to 0.25 wavelength of television radio waves. Use it vertically. The zigzag antenna conductor 12 shown in FIG. 5 has an antenna conductor having a thickness of about 0.01 wavelength of a TV radio wave and a length of about a half wavelength of the TV radio wave at both sides of the feeding point 4 at bending angles of about 60 degrees three to five times. It is formed by bending in a zigzag shape, and its terminal end is short-circuited to the metal reflector 9. By feeding the transmission current from the feeding point 4 to the zigzag antenna conductor 12, the zigzag antenna 13 can be made an efficient transmission antenna with a large gain.

The zigzag antenna 13 shown in FIG. 5 can be used as a receiving antenna according to the reciprocity theorem of the antenna. However, in the case of using for receiving VHF band television waves having a long wavelength, the number of conventional examples is extremely small because the antenna shape becomes large and the transportation and installation are restricted. However, the zigzag antenna 13 shown in FIG. 5 is suitable for use as a television wave reflection suppression antenna in the following points.

Since the area intersecting with the arriving television wave (hereinafter, sometimes referred to as an opening area) is large, the number of antennas required to cover the outer wall surface of the structure in the radio wave arrival direction can be reduced. Further, the number of impedance matching resistors for power consumption required for each antenna can be saved. The height of the antenna from the metal reflection plate can be suppressed to be lower than that of a super gain antenna, a dipole antenna, or the like, and the antenna can be installed without greatly protruding from the outer wall surface of the structure.

On the other hand, it is necessary to use an antenna having a wide band characteristic in order to suppress the reflection of the television wave of each channel. In this regard, the zigzag antenna 13 of FIG.
Even if the antenna conductor length, thickness, height from the wall, resistance value of the impedance matching resistor, etc. are designed optimally, it is about the same as the fractional band of the super gain antenna.
Only a 15% narrow band (for example, a band of 30 MHz at 200 MHz) can be secured. Therefore, the zigzag antenna 13 of FIG.
Although there is no problem as a transmitting antenna, the reflection suppressing antenna can be expected to suppress only the reflection of a limited two or three channel television wave, and cannot cope with a plurality of channels of television wave. The present inventors have developed a technique for giving a zigzag antenna a broadband characteristic, and have completed the present invention.

Referring to the embodiment of FIG. 1, the antenna 10 for suppressing reflection of television waves of the present invention has a vertical outer wall 7 of a structure.
A plurality of antenna support members 5 capable of supporting two antenna conductors in upper and lower stages in parallel with the outer wall surface 7 at predetermined intervals H ₁ and H ₂ from the outer wall surface 7, and upper and lower antenna conductors Upper and lower two-stage zigzag antennas 2 ₁ , 2 ₂ extending vertically upward and downward from predetermined feed points 4 ₁ , 4 ₂ , respectively, and supported and bent by an antenna support 5 provided at a predetermined zigzag bending position. And an impedance matching resistor 11 connected between the feeding points 4 ₁ and 4 ₂ of the upper and lower zigzag antennas 2 ₁ and 2 ₂ , and the frequency of a television radio wave whose reflection L should be suppressed for the interval L between adjacent zigzag bending positions. A part of the electric power of the television wave incident on the vertical outer wall surface 7 is scattered in accordance with the band, and a part of the electric power is consumed by the resistor.

The antenna conductor is made of a material which is hardly corroded. For example, a stainless wire having a thickness of about 1 mm can be used as the antenna conductor. However, the antenna conductor used in the present invention is not limited to one having a thickness of about 1 mm, and is experimentally thick according to the frequency band of the television wave to be suppressed to the extent that the appearance of the outer wall of the structure is not impaired. Can be adjusted. The antenna support is made of an insulating material having excellent weather resistance so as to withstand various weather conditions, and may be made of, for example, reinforced plastic (FRP) or Teflon. The impedance matching resistor 11 is sealed in a case or the like in consideration of weather resistance, and more preferably, the case is filled with a filler and sealed therein. Both ends of the upper and lower zigzag antennas 2 ₁ and 2 ₂ can be open or short-circuited together.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The reflection suppressing antenna 10 of the present invention
The zigzag antenna 13 shown in FIG. 5 constitutes an efficient antenna by combining the phases of radio waves between the metal reflector 9 and the zigzag antenna conductor 12, whereas the arrangement of reinforcing bars in the outer wall 7 of the structure corresponding to the metal reflector is made. An antenna is formed between the antenna and the zigzag antenna 2, and the metal reflector 9 as shown in FIG. 5 is not used. With the omission of the metal reflector 9, a method of consuming power by connecting the impedance matching resistor 11 between the zigzag antenna conductor 12 and the metal reflector 9 as shown in FIG. Then, the mounting position of the resistor 11 becomes a problem. Reflection suppressing antenna 10 of the present invention is a zigzag antenna 2 _1, 2 ₂ of upper and lower stages is provided, attach the zigzag antenna 2 _1, 2 ₂ of the feed point _41, 42 the impedance matching resistor 11 between the _second two-stage.

The distances H ₁ and H ₂ between the zigzag antennas 2 ₁ and 2 ₂ and the outer wall 7 of the structure (hereinafter, sometimes referred to as antenna heights) are determined by the thickness of the reinforcing bars in the wall, the length and width. Based on the size of the mesh of the reinforcing bars, the distance from the outer wall surface 7 to the reinforcing bars, and the like, the frequency characteristics with respect to the television wave targeted for reflection suppression are experimentally determined so as to be optimal. The antenna heights H ₁ and H ₂
Not only the zigzag antenna 2 _1, 2 ₂ spacing between adjacent zigzag folded position L (see FIG. 1. Hereinafter sometimes referred to antenna element length.), Bending angle of the zigzag antenna 2 _1, 2 ₂ , The vertical length P per bending unit (refer to FIG. 1, hereinafter sometimes referred to as a bending pitch), the resistance value R of the impedance matching resistor 11, and the thickness of the antenna conductor. The relationship between the reflection suppression antenna 10 and the frequency band of the television wave to be subjected to reflection suppression can be experimentally obtained in advance, and the optimum value can be determined by referring to the experimental result when the antenna is installed. The power capacity of the resistor of the impedance matching resistor 11 can be relatively weak, for example, the power consumption is less than 1 watt.

[Experimental example 1] The reflection suppressing antenna 10 of the present invention.
In order to examine the relationship between the antenna element length L and the frequency characteristic, an experiment was conducted in which four sets of one-stage zigzag antennas 2 formed of one antenna conductor were arranged in a line on the left and right on a wall surface block. In this experiment, the antenna height H of each zigzag antenna 2 was 86 mm, the bending pitch P was 600 mm, the horizontal distance D (see FIG. 2) was 800 mm, and the resistance value R of the impedance matching resistor 11 was 300Ω. Using the free space standing wave method as a measuring method, the antenna element length L of each zigzag antenna 2 was changed to 600 mm, 680 mm, and 770 mm, and the frequency characteristics of the return loss were measured. The results of this experiment are shown in the graph of FIG. As can be seen from the graph of FIG. 3, when the antenna element length L is changed to 600 mm, 680 mm, and 770 mm, the frequency at which the return loss is maximized is 205
MHz, 182 MHz, and 160 MHz. By this experiment, it was confirmed that the frequency band of the television wave to be suppressed from being reflected can be changed according to the antenna element length L of the zigzag antenna 2. In order to facilitate the actual antenna design, the wavelength reduction rate can be obtained by this experiment.

Various parameters such as the antenna height H, the bending pitch P, the resistance value R of the impedance matching resistor 11, and the thickness of the antenna conductor of the zigzag antenna 2 are the same as in the case of the antenna element length L described above. To
By experimentally obtaining the frequency characteristics of the return loss rate while changing only specific parameters, it is possible to determine a parameter value that maximizes the return loss rate in the frequency band of the reflection suppression target.

[Experimental example 2] Reflection suppression antenna 10 of the present invention
In this embodiment, the zigzag antennas 2 ₁ , 2 ₂ are arranged in two stages in the vertical direction, thereby suppressing the reflection of television radio waves in a wider band than in the case of the single stage zigzag antenna 2. In order to confirm this, a plurality of sets of zigzag antennas 2 ₁ , 2 ₂ of upper and lower stages as shown in FIG. The frequency characteristics of return loss were measured using the standing wave method. In this experiment, the height H _{1 of the} lower antenna was 49 mm, and the height H _{2 of the} upper antenna was
116 mm, the zigzag antenna 2 _1, 2 ₂ of the antenna element 680mm length L, a crooked 600mm pitch P, lateral spacing D
(See FIG. 2) was 800 mm, and the resistance value R of the impedance matching resistor 11 was 500Ω. The results of this experiment are shown in the graph of FIG. As can be seen from the graph of FIG. 4, the upper and lower zigzag antennas 2 ₁ and 2 ₂ have frequency characteristics in which the return loss is maximized at two frequencies of 160 MHz and 200 MHz, and are sufficiently large for a wide frequency band. It was confirmed that the sample exhibited a return loss.

In the graph of FIG. 4, the maximum at 200 MHz is based on the antenna element length L, and is 160 MHz.
Is considered to be based on other various parameters such as the heights H ₁ and H ₂ of the upper and lower antennas and the resistance value R of the impedance matching resistor 11. In short, in the reflection suppressing antenna 11 of the present invention, a current flows through the two-step antenna conductor formed by the two-stage zigzag antennas 2 ₁ and 2 ₂ , and a good antenna is formed between the antenna and the reinforcing members in the wall surface. It is considered that the matching is achieved by self-consumption of the induced current due to the high resistance value of R and the resistance value R of the impedance matching resistor 11 at the feeding point 4. Since the frequency band in which the return loss in the graph of FIG. 4 is maximized varies depending on the conditions of various parameters, optimal values of various parameters of the reflection suppression antenna 10 suitable for suppressing reflection of a desired television wave are experimentally determined.

The reflection suppressing antenna 10 of the present invention is installed without impairing the aesthetic appearance of the structure, for example, by using a sufficiently thin antenna conductor and making the color of the antenna support 5 the same color as the outer wall surface 7 of the structure. It is possible to It is expected that the thickness and color of the antenna support 5 and the thickness of the antenna conductor are determined in view of the design, and that the anti-reflection antenna 10 of the present invention stretched on the wall is positively utilized as a wall design.

In this manner, the object of the present invention, that is, the provision of "a TV radio wave reflection suppression antenna which is inexpensive and does not impair the aesthetics of the structure" can be achieved.

[0019]

FIG. 1 shows an embodiment in which two reflection suppressing antennas 10 of the present invention are installed in parallel on the outer wall surface 7 of a structure. Referring to FIG. 1, an example of a method of installing the reflection suppressing antenna 10 of the present invention will be described. First, an antenna support 5 provided with upper and lower antenna conductor locking portions is attached to a vertical outer wall 7 of a structure. Attach to the above specified zigzag bending position. The antenna support 5 can be attached by directly providing an anchor hole on the outer wall surface 7 of the structure. However, the outer wall 7 of the structure has an anchor hole for attaching the antenna support 7 at a predetermined interval in advance. The support 5 can be attached by selecting an appropriate anchor hole. The antenna conductor locking portion of the support 5 can be, for example, a locking hole large enough to allow the antenna conductor to penetrate.

The upper and lower antenna conductors are stretched vertically upward and downward from a predetermined feeding point, and are bent by being locked to the upper and lower locking portions of each support 5 attached at a predetermined zigzag bending position. As a result, zigzag antennas 2 ₁ and 2 ₂ in the upper and lower stages are formed. The length of the antenna conductor can be determined in consideration of, for example, the half wavelength of the television wave to be suppressed and the above-described wavelength reduction rate. For example, the antenna conductor is locked to the upper and lower two-stage locking portions of the support 5 at the feeding point position 4, and the antenna conductor is locked from the support 5 to the support 5 at the predetermined zigzag bending position sequentially in two stages. The zigzag antennas 2 ₁ and 2 ₂ are formed by extending vertically upward and vertically downward and connecting the two upper antenna wires and the two lower antenna wires at the feeding point position 4 while maintaining appropriate tensions. You can also.

The zigzag antenna 2 _1, 2 vertically upward side and the vertically downward direction side of the _second feed point can be symmetrical. However, the zigzag antenna 2 in the present invention is not limited to a vertically symmetric antenna. Zigzag antenna 2 ₁ , 2 ₂
Are opened with appropriate tension, respectively, or the upper and lower ends are short-circuited. It is possible to form the reflection suppressing antenna 10 of the present invention by attaching an impedance matching resistor 11 between the upper and lower stages zigzag antenna 2 _1, 2 ₂ of the feeding point.

FIG. 2 shows an embodiment of the present invention in which a plurality of reflection suppression antennas 10 are provided on a wide vertical outer wall 7 on the radio wave arrival side of a structure. In the embodiment of FIG. 2, a plurality of reflection suppressing antennas 10 are arranged on the outer wall 7 at predetermined vertical intervals A and horizontal intervals D.
It is arranged in. The vertical interval A and the horizontal interval D can be appropriately determined, for example, using the technology of an array antenna belonging to the prior art. The vertical interval A may be substantially the same as the bending pitch P of the zigzag antenna 2, for example. As described above, the reflection suppressing antenna of the present invention
Since 10 has a large opening area, it can cover a wide outer wall surface 7 with a small number of antennas.

The anti-reflection antenna 10 of the present invention achieves a wide band by using two-stage zigzag antennas 2 ₁ and 2 _2. One type of anti-reflection antenna 10 supports all channels of VHF band television waves. Sometimes it is not possible. In such a case, for example, two types of reflection suppression antennas 10 of a low frequency band compatible antenna and a high frequency band compatible antenna are alternately arranged, and VHF is used by the two types of reflection suppression antennas 10.
It can correspond to all channels of the TV band.

[0024]

As described above in detail, the reflection suppressing antenna according to the present invention is provided with a plurality of upper and lower antenna conductor locking portions, and is provided at a predetermined zigzag bending position on the vertical outer wall surface of the structure. The upper and lower two-stage zigzags are formed by extending the antenna support and the upper and lower two-stage antenna conductors vertically upward and downward from a predetermined feeding point and supporting and bending the antenna support attached to the predetermined zigzag bending position. Antenna, and an impedance matching resistor connected between the feeding points of the upper and lower two-stage zigzag antennas, and the interval between adjacent predetermined zigzag bending positions corresponds to the frequency band of the television wave to be suppressed in reflection, so that It works.

(A) The reflection of broadband television waves can be suppressed with a simple structure. (B) Adjustment of the frequency band of the reflection suppression target can be relatively easily adjusted by the arrangement of the antenna support and the like. (C) By alternately arranging two or more types of antennas having different radio frequency bands to be subjected to reflection suppression, it is possible to reliably suppress reflection of TV radio waves in a wider band. (D) Since the area that intersects with a radio wave is larger than that of a linear antenna, the outer wall on the radio wave arrival side can be covered with a small number of antennas, and the number of resistors can be reduced. (E) It can be installed without impairing the appearance of the outer wall of the structure.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of one embodiment of the present invention.

FIG. 2 is an explanatory diagram of another embodiment of the present invention.

FIG. 3 is a graph illustrating a frequency characteristic of return loss according to a change in element length of a zigzag antenna.

FIG. 4 is a graph showing frequency characteristics of return loss by a two-stage zigzag antenna.

FIG. 5 is an explanatory diagram of a conventional zigzag antenna.

[Explanation of symbols]

 2 Zigzag antenna 4 Feed point 5 Antenna support 7 Structure outer wall 9 Metal reflector 10 Reflection suppression antenna 11 Impedance matching resistor 12 Zigzag antenna conductor 13 Zigzag antenna A Vertical spacing D Horizontal spacing H Antenna height L Antenna element length P Bending pitch R Resistance value.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Tadao Naito 4-51 Otacho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Kashima Construction Co., Ltd. Yokohama Branch (72) Inventor Kenichiro Mizuno 4-chome, Otacho, Naka-ku, Yokohama-shi, Kanagawa 51 Kashima Construction Co., Ltd., Yokohama Branch (72) Inventor Kentaro Sugimoto 4-51 Otacho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Kashima Construction Co., Ltd., Yokohama Branch (72) Inventor Yoshihiro Narita Higashi-Ueno, Taito-ku, Tokyo No. 1-5, Nippon Cable Network Systems Co., Ltd. (72) Inventor Masago Otsu 7-12-22 Ishigami Idai Corp., Nerima-ku, Tokyo 308 (56) References JP-A-7-15225 (JP, A) JP-A-1-173906 (JP, A) JP-A-1-120903 (JP, A) JP-A-62-17214 (JP, U)

Claims (7)

(57) [Claims] 1. A plurality of antenna support members capable of supporting two antenna conductors on the vertical outer wall surface of a structure in parallel with the outer wall surface at a predetermined distance from the outer wall surface, the two antenna conductors being upper and lower stages. An upper and lower two-stage zigzag antenna formed by extending and forming an antenna conductor vertically upward and downward from a predetermined feeding point and supporting and bending the antenna conductor provided at a predetermined zigzag bending position, and a two-stage zigzag An impedance matching resistor connected between the feeding points of the antenna, wherein an interval between the adjacent zigzag bending positions corresponds to a frequency band of a television wave to be reflected and suppressed, and a power of the television wave incident on the vertical outer wall surface is reduced by one. An antenna for suppressing reflection of television waves, which is partially scattered and partially consumed by the resistor. 2. The anti-reflection antenna according to claim 1, wherein both ends of said upper and lower zigzag antennas are short-circuited. 3. The reflection suppressing antenna according to claim 1, wherein a predetermined gap between each of said zigzag antennas and said outer wall surface, a bending angle of said antenna conductor at each of said zigzag bending positions, An antenna for suppressing reflection of television waves, wherein a resistance value and / or a thickness of the antenna conductor correspond to a frequency band of television waves to be suppressed for reflection. 4. The antenna for suppressing reflection of television waves according to claim 1, wherein said antenna conductor is a stainless wire having a diameter of about 1 mm and said support is made of reinforced plastic or Teflon. 5. An antenna support provided with upper and lower antenna conductor locking portions is mounted at a predetermined zigzag bending position on a vertical outer wall of a structure, and the upper and lower antenna conductors are separated from predetermined feeding points. The upper and lower zigzag antennas are stretched vertically upward and downward, and each of the supports at the zigzag bending position is locked by the upper and lower locking portions and bent to form a two-stage upper and lower zigzag antenna. A reflection suppression antenna is formed by connecting an impedance matching resistor between points, and the interval between the adjacent zigzag bending positions is made to correspond to the frequency band of the television wave to be suppressed for reflection. A method for suppressing reflection of television radio waves, which partially scatters electric power and partially consumes the electric power by the resistor. 6. The reflection suppressing method according to claim 5, wherein a plurality of said reflection suppressing antennas are provided on a vertical outer wall surface of said structure. 7. The reflection suppressing method according to claim 6, wherein two or more types of said reflection suppressing antennas corresponding to different frequency bands are provided on a vertical outer wall surface of said structure.