Broadcasting reception antenna device

Abstract

To provide a broadcasting reception antenna device that can be easily installed even in a narrow space and has increased reception sensitivity over a wide bandwidth.SOLUTION: The broadcasting reception antenna device corresponds to the reception of radio waves with a frequency of 470 MHz or more and 710 MHz or less. The broadcasting reception antenna device has a substrate, a radiating element provided on the substrate, a reflecting element provided on the substrate, and a waveguide element provided on the substrate. The reflection element, the radiating element, and the waveguide element are provided to be arranged in the first direction in this order. The radiating element has a width W3 in the first direction. When a length in a second direction perpendicular to the first direction is denoted as L3, a ratio W3 / L3 is 0.10 or more and 0.50 or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a broadcast receiving antenna device.

Background Art

[0002] For receiving terrestrial digital television broadcasts (hereinafter referred to as "terrestrial digital broadcasts"), an antenna device capable of receiving radio waves in the UHF band is used.

[0003] For example, Patent Document 1 discloses a Yagi-Uda antenna for receiving terrestrial digital broadcasts, which includes a radiator, a reflector, and a waveguide. This Yagi-Uda antenna is made of a metal material such as aluminum. It is installed on the roof or rooftop of a house and fixed in the direction from which radio waves arrive.

[0004] However, since conventional antennas for receiving terrestrial digital broadcasts are installed outdoors, there is a concern that they may be tilted or damaged by strong winds. In addition, it is also a problem that the appearance of the building is impaired. On the other hand, although indoor antenna devices are also known, they have a problem of low reception sensitivity. In addition, outdoor antenna devices are difficult to install indoors from the viewpoint of size.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide a broadcast receiving antenna device that can be easily installed in a narrow space and has high reception sensitivity in a wide band.

Means for Solving the Problems

[0007] Such an object is achieved by the present invention described in the following (1) to (9). (1) A broadcast receiving antenna device corresponding to reception of radio waves having a frequency of 470 MHz or more and 710 MHz or less, a substrate, a radiating element provided on the substrate, a reflecting element provided on the substrate, a waveguide element provided on the substrate, and having, the reflecting element, the radiating element, and the waveguide element are provided so as to be arranged in the first direction in this order, when the width of the radiating element in the first direction is W3 and the length in the second direction orthogonal to the first direction is L3, the ratio W3 / L3 is 0.10 or more and 0.50 or less. A broadcast receiving antenna device characterized by that.

[0008] (2) The broadcast receiving antenna device according to (1) above, wherein when the width of the reflecting element in the first direction is W4 and the length in the second direction is L4, the ratio W4 / L4 is 0.03 or more and 0.25 or less.

[0009] (3) The broadcast receiving antenna device according to (1) or (2) above, wherein the distance between the radiating element and the reflecting element is 60 mm or more and 170 mm or less.

[0010] (4) The broadcast receiving antenna device according to (1) or (2) above, wherein the constituent material of the substrate is a resin material.

[0011] (5) The broadcast receiving antenna device according to (1) or (2) above, wherein the substrate is divided into at least a first component and a second component.

[0012] (6) The broadcast receiving antenna device according to (5) above, wherein the substrate has an engaging structure for engaging the first component and the second component with each other.

[0013] (7) The broadcast receiving antenna device according to (1) or (2) above, which is installed in the attic of a building.

[0014] (8) The broadcast receiving antenna device according to (1) or (2) above, which is installed between the structural material of the building and the waterproof sheet.

[0015] (9) The broadcast receiving antenna device according to (1) or (2) above, which is composed of the radiation element, the reflection element, and the waveguide element, and has a plurality of element groups provided on the substrate.

Effect of the Invention

[0016] According to the present invention, a broadcast receiving antenna device that can be easily installed even in a narrow space and has high reception sensitivity in a wide band can be obtained.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0018] Hereinafter, the broadcast receiving antenna device according to the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.

[0019] FIG. 1 is a top view showing the configuration of the broadcast receiving antenna device 1 according to the embodiment. FIG. 2 is a cross-sectional view of the broadcast receiving antenna device 1 shown in FIG. 1. In each figure of the present application, the X-axis, Y-axis, and Z-axis are set as three mutually orthogonal axes. Each axis is represented by an arrow, and the tip side of the arrow is defined as "plus" and the base end side of the arrow is defined as "minus". In the following description, for example, the "X-axis direction" includes both the plus direction and the minus direction of the X-axis. The same applies to the Y-axis direction and the Z-axis direction. Further, in the following description, particularly, the Z-axis plus side is also referred to as "up", and the Z-axis minus side is also referred to as "down".

[0020] The broadcast receiving antenna device 1 shown in FIGS. 1 and 2 includes a substrate 2 and an element group 10. The element group 10 is composed of a radiation element 3, a reflection element 4, and a waveguide element 5 provided on the substrate 2. The reflection element 4, the radiation element 3, and the waveguide element 5 are arranged in this order toward the X-axis plus side.

[0021] By arranging the elements in this way, the broadcast receiving antenna device 1 can receive a broadcast wave (radio wave) arriving from the X-axis plus side toward the X-axis minus side with high sensitivity. Further, the broadcast receiving antenna device 1 has an overall plate shape. Therefore, the broadcast receiving antenna device 1 is excellent in portability and can be easily installed even in a narrow space. Examples of the broadcast wave include radio waves having a frequency of 470 MHz or more and 710 MHz or less. Radio waves of this frequency are used, for example, as domestic terrestrial digital broadcast waves, as well as overseas digital television broadcast waves and analog television broadcast waves.

[0022] 1. Configuration of Broadcast Receiving Antenna Device First, the configuration of the broadcast receiving antenna device 1 will be described.

[0023] 1.1. Substrate The substrate 2 has a plate shape extending along the X-Y plane. The substrate 2 has a lower surface 21 and an upper surface 22 that are in a front-back relationship with each other. The plate shape means a shape in which the thickness of the substrate 2 is sufficiently shorter than the lengths of the sides of the lower surface 21 and the upper surface 22.

[0024] The thickness t2 of the substrate 2 shown in FIG. 2 is not particularly limited, but for example, it is preferably 100 μm or more and 10 mm or less, and more preferably 200 μm or more and 5 mm or less. Thereby, the weight of the substrate 2 can be reduced, and the broadcast receiving antenna device 1 that is easy to handle can be realized.

[0025] The size of the substrate 2 is appropriately set according to the length, width, interval, number, etc. of the radiation element 3, the reflection element 4, and the waveguide element 5.

[0026] Taking into account the radio field intensity of domestic terrestrial digital broadcast waves and the operating gain required for good reception, the length L2 of the substrate 2 in the X-axis direction is preferably 300 mm or more and 3000 mm or less, and more preferably 500 mm or more and 2000 mm or less. Also, the width W2 of the substrate 2 in the Y-axis direction is preferably 300 mm or more and 1500 mm or less, and more preferably 400 mm or more and 1000 mm or less.

[0027] Examples of the constituent material of the substrate 2 include resin materials, ceramic materials, glass materials, etc. Also, a composite material containing one or more of these may be used.

[0028] Examples of the resin material include various thermoplastic resins such as olefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate, polyvinyl chloride resins, thermoplastic polyurethanes, thermoplastic polyimides, polyamides, polyether ketones such as polyether ether ketone, polyether sulfones, polystyrenes, fluorine resins, cellulose resins, styrene-based thermoplastic elastomers (styrene-based polymers), acrylic resins, polyester-based thermoplastic elastomers, polycarbonates (carbonate-based polymers), etc., and various thermosetting resins such as thermosetting polyurethanes, thermosetting polyimides, phenol resins, epoxy resins, silicone resins, urea resins, and melamine resins. Also, a polymer blend or polymer alloy composed of one or more of these may be used.

[0029] Further, these resin materials may be in a fibrous form. Examples of the form of the fibrous resin material include fabrics such as non-woven fabrics and woven fabrics, meshes, chopped strands, and the like.

[0030] Examples of the ceramic material include alumina, zirconia, magnesia, titania, silica, and the like. Examples of the glass material include glass cloth and the like.

[0031] As the constituent material of the substrate 2, a resin material is preferably used. By using a resin material, the weight of the broadcast receiving antenna device 1 can be reduced.

[0032] Also, when the end portion of the substrate 2 in the X-axis direction is cantilever-supported, for example, the substrate 2 may have rigidity such that it does not bend under its own weight, or may have flexibility such that it bends under its own weight. In the former case, since the flatness of the substrate 2 is easily maintained, the efficiency of the installation work of the broadcast receiving antenna device 1 can be easily increased. In the latter case, for example, the substrate 2 can be stored and transported in a wound state. Therefore, the efficiency of storage, transportation, etc. can be easily increased.

[0033] 1.2. Radiation Element The radiation element 3 is disposed on the upper surface 22 of the substrate 2. The radiation element 3 shown in FIG. 1 has element conductors 3a and 3b. The element conductors 3a and 3b are each in a strip shape extending along the Y-axis. Further, the element conductors 3a and 3b are arranged in the Y-axis direction with a gap therebetween. Thereby, a dipole antenna is formed. These element conductors 3a and 3b are connected to a feeding line (not shown). As a result, a signal corresponding to the broadcast wave received by the radiation element 3 flows through the feeding line. This signal is received by a display device (not shown) and demodulated into video, audio, various data, and the like.

[0034] The length L3 of the radiation element 3 in the Y-axis direction (the second direction) (the length from the Y-axis positive side end of the element conductor 3a to the Y-axis negative side end of the element conductor 3b) is set to be about 1 / 2 of the wavelength λ of the received broadcast wave, for example, but it may be longer or shorter than this. For example, the wavelength of the radio wave propagating in the radiation element 3 becomes shorter than the wavelength λ of the broadcast wave. Therefore, the length L3 is preferably (1 / 2)λ or less, more preferably (1 / 4)λ or more and less than (1 / 2)λ, and even more preferably (1 / 3)λ or more and less than (1 / 2)λ. Specifically, it is preferably 160 mm or more and 320 mm or less, and more preferably 200 mm or more and 300 mm or less. Thereby, a broadcast receiving antenna device 1 having high reception sensitivity can be realized in a sufficiently wide band.

[0035] Also, let the width of the radiation element 3 in the X-axis direction (the first direction) be W3. The ratio W3 / L3 of the width W3 to the length L3 of the radiation element 3 is set to be 0.10 or more and 0.50 or less, preferably 0.13 or more and 0.35 or less. By setting the ratio W3 / L3 within the above range, the shape of the radiation element 3 is optimized, so that a broadcast receiving antenna device 1 having high reception sensitivity can be realized in a sufficiently wide band.

[0036] Note that if the ratio W3 / L3 falls below the lower limit value or exceeds the upper limit value, the balance of the shape of the radiation element 3 may deteriorate, the reception sensitivity may decrease, or the band that can be received with high sensitivity may become narrow.

[0037] The thickness t3 of the radiation element 3 shown in FIG. 2 is not particularly limited, but is preferably 5 μm or more and 1000 μm or less, more preferably 10 μm or more and 300 μm or less, and even more preferably 15 μm or more and 100 μm or less. When the thickness t3 is within the above range, the electrical resistance of the radiation element 3 can be kept low and the manufacturability of the radiation element 3 can be improved.

[0038] The constituent material of the radiation element 3 is not particularly limited, and examples thereof include simple substances of metal elements such as copper, aluminum, nickel, silver, and gold, and metal materials such as alloys containing these. Examples of the form of the radiation element 3 include foils of these metal materials, conductive paste coatings, conductive ink coatings, and the like.

[0039] 1.3. Reflective Element The reflective element 4 is disposed on the upper surface 22 of the substrate 2. The reflective element 4 shown in FIG. 1 has a strip shape extending along the Y-axis. The reflective element 4 is disposed on the minus X-axis side of the radiation element 3. The reflective element 4 reflects the incoming broadcast wave to the radiation element 3, thereby enhancing the directivity of the broadcast receiving antenna device 1. As a result, the operating gain of the broadcast receiving antenna device 1 is increased.

[0040] The length L4 of the reflective element 4 in the Y-axis direction (second direction) is preferably longer than the length L3 of the radiation element 3. Thereby, the reflection efficiency of the broadcast wave by the reflective element 4 can be enhanced.

[0041] The length L4 is set to about 1 / 2 of the wavelength λ of the received broadcast wave, for example, but it may be longer or shorter than this. For example, the length L4 is preferably (1 / 4)λ or more, and more preferably (1 / 3)λ or more and (2 / 3)λ or less. Thereby, a broadcast receiving antenna device 1 having high reception sensitivity can be realized in a sufficiently wide band.

[0042] Also, let the width of the reflective element 4 in the X-axis direction (first direction) be W4. The ratio W4 / L4 of the width W4 to the length L4 of the reflective element 4 is not particularly limited, but is preferably 0.03 or more and 0.25 or less, more preferably 0.04 or more and 0.20 or less, and even more preferably 0.05 or more and 0.15 or less. By setting the ratio W4 / L4 within the above range, a broadcast receiving antenna device 1 having high reception sensitivity can be realized in a sufficiently wide band.

[0043] In addition, if the ratio W4 / L4 is below the lower limit or above the upper limit, the balance of the shape of the reflector 4 deteriorates, and there is a risk that the reception sensitivity decreases or the band that can be received with high sensitivity becomes narrow.

[0044] The distance S3-4 between the radiator 3 and the reflector 4 is appropriately set according to the wavelength λ of the broadcast wave to be received. For example, it is set to about (1 / 4)λ, preferably (1 / 8)λ or more and (1 / 3)λ or less, and more preferably (1 / 6)λ or more and (1 / 4)λ or less. Specifically, it is preferably 60 mm or more and 170 mm or less, and more preferably 100 mm or more and 160 mm or less. Thereby, the reflection efficiency of the broadcast wave in the reflector 4 becomes higher. As a result, the operating gain of the broadcast reception antenna device 1 can be further increased.

[0045] The thickness of the reflector 4 is not particularly limited, but is preferably within the range of the thicknesses listed as the thickness t3 of the radiator 3.

[0046] The constituent material and form of the reflector 4 are not particularly limited, but are preferably appropriately selected from those listed as the constituent material and form of the radiator 3.

[0047] 1.4. Waveguide element The waveguide element 5 is disposed on the upper surface 22 of the substrate 2. The waveguide element 5 shown in FIG. 1 has element conductors 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k, 5L. These 12 element conductors 5a to 5L are each in a strip shape extending along the Y axis. Further, the element conductors 5a to 5L are arranged in the X-axis direction with a gap therebetween. The waveguide element 5 guides the incoming broadcast wave to the radiator 3, enhances the directivity of the broadcast reception antenna device 1, and increases the operating gain.

[0048] The length L5 of the waveguide element 5 in the Y-axis direction (second direction) (the length of the element conductors 5a to 5L in the Y-axis direction) is preferably shorter than the length L3 of the radiation element 3. Thereby, the induction efficiency of the broadcast wave by the waveguide element 5 can be increased. The length L5 is set, for example, to be shorter than about 1 / 2 of the wavelength λ of the received broadcast wave, but it may be longer or shorter than this. For example, the length L5 is preferably (1 / 2)λ or less, and more preferably (1 / 8)λ or more and less than (1 / 2)λ. Thereby, a broadcast receiving antenna device 1 having high reception sensitivity can be realized in a sufficiently wide band.

[0049] Also, let each width of the element conductors 5a to 5L in the X-axis direction (first direction) be W5. The ratio W5 / L5 of the width W5 to the length L5 of the waveguide element 5 is not particularly limited, but is preferably 0.03 or more and 0.30 or less, and more preferably 0.05 or more and 0.20 or less. By setting the ratio W5 / L5 within the above range, a broadcast receiving antenna device 1 having high reception sensitivity can be realized in a sufficiently wide band.

[0050] Note that if the ratio W5 / L5 falls below the lower limit value or exceeds the upper limit value, the balance of the shape of the waveguide element 5 may deteriorate, the reception sensitivity may decrease, or the band that can be received with high sensitivity may become narrow.

[0051] The distance S3-5 between the radiation element 3 and the waveguide element 5 is appropriately set according to the wavelength λ of the received broadcast wave. For example, it is set to about (1 / 4)λ, but is preferably (1 / 8)λ or more and (1 / 3)λ or less, and more preferably (1 / 6)λ or more and (1 / 4)λ or less. Specifically, it is preferably 20 mm or more and 150 mm or less, and more preferably 25 mm or more and 100 mm or less. Thereby, a broadcast receiving antenna device 1 having high reception sensitivity can be realized in a sufficiently wide band.

[0052] In addition, in this specification, the "interval" is defined starting from the intermediate line in the X-axis direction of the conductor constituting each element. For example, the interval S3-5 is the distance between the intermediate line in the X-axis direction of the radiation element 3 and the intermediate line in the X-axis direction of the element conductor 5a.

[0053] The interval S5-5 between the element conductors 5a to 5L is appropriately set according to the wavelength λ of the broadcast wave to be received. For example, it is set to about (1 / 4)λ, preferably (1 / 8)λ or more and (1 / 3)λ or less, and more preferably (1 / 6)λ or more and (1 / 4)λ or less. Specifically, it is preferably 20 mm or more and 150 mm or less, and more preferably 25 mm or more and 100 mm or less. Thereby, a broadcast receiving antenna device 1 having high reception sensitivity can be realized in a sufficiently wide band. Note that the interval S5-5 is the interval between adjacent element conductors.

[0054] The thickness of the waveguide element 5 is not particularly limited, but is preferably within the range of the thicknesses listed as the thickness t3 of the radiation element 3.

[0055] The constituent material and form of the waveguide element 5 are not particularly limited, but are preferably appropriately selected from those listed as the constituent material and form of the radiation element 3.

[0056] The number of element conductors included in the waveguide element 5 is not limited to 12, and may be 1 or more and 11 or less, or 13 or more. The larger the number of element conductors, the easier it is to increase the directivity and operating gain of the broadcast receiving antenna device 1. However, considering the balance between the operating gain and the directivity and the size, it is preferably 2 or more and 30 or less, and more preferably 4 or more and 20 or less.

[0057] 2. First Modified Example Next, a first modified example of the broadcast receiving antenna device 1 according to the embodiment will be described. FIG. 3 is a top view showing a first modified example of the broadcast receiving antenna device 1 according to the embodiment.

[0058] Next, a first modification will be described. In the following description, the differences from the above-described embodiment will be mainly described, and the description of the same matters will be omitted. In FIG. 3, the same matters as those in the above-described embodiment are denoted by the same reference numerals.

[0059] In the broadcast receiving antenna device 1 shown in FIG. 3, the substrate 2 shown in FIG. 1 is divided into a first component 2a, a second component 2b, and a third component 2c. Among the waveguide elements 5 described above, the element conductors 5a, 5b, 5c, 5d are arranged on the upper surface 22a of the first component 2a, the element conductors 5e, 5f, 5g, 5h are arranged on the upper surface 22b of the second component 2b, and the element conductors 5i, 5j, 5k, 5L are arranged on the upper surface 22c of the third component 2c. Note that the number of divisions of the substrate 2 is not limited to 3 as described above, and may be 2 or 4 or more.

[0060] By dividing the substrate 2 in this way, a broadcast receiving antenna device 1 with excellent portability and easy to install in a narrow space can be realized. Further, the second component 2b and the third component 2c shown in FIG. 3 may be connected to the first component 2a according to the electric field strength at the installation location. For example, when the electric field strength is sufficiently strong, they may be omitted. That is, the second component 2b and the third component 2c are used to increase the operating gain and directivity, and can be omitted when not necessary. Thereby, the reception sensitivity and directivity can be optimized, and the substrate 2 can be miniaturized.

[0061] Further, the substrate 2 may simply be divided, or may have engaging structures 201 and 202.

[0062] Specifically, an engaging portion 25 is provided on the first component 2a shown in FIG. 3, and an engaged portion 35A that can engage with the engaging portion 25 is provided on the second component 2b. The engaging portion 25 and the engaged portion 35A constitute an engaging structure 201 that engages with each other. With this engaging structure 201, the first component 2a and the second component 2b can be connected with high positional accuracy.

[0063] In addition, an engaging portion 35B is provided on the second component 2b shown in FIG. 3, and an engaged portion 45 is provided on the third component 2c. The engaging portion 35B and the engaged portion 45 constitute an engaging structure 202 that engages with each other. With this engaging structure 202, the second component 2b and the third component 2c can be connected with high positional accuracy.

[0064] Note that the form of engagement is not limited to the form shown in FIG. 3 (the fitting of a convex portion and a concave portion). Since the engagement can be realized by any mechanism in which components are engaged with each other, the specific form is not particularly limited. To give an example of the form of engagement, fitting of a hole and a protrusion, clamping using an elastic body such as a clip, fixing via an adhesive, an adhesive agent, an adhesive tape, an adhesive tape, a hook-and-loop fastener, etc., lamination using a covering material, accommodation in a laminated substrate, etc. can be mentioned.

[0065] On the other hand, the engaging structures 201 and 202 are preferably structures in which the engagement can be released. Thereby, for example, even when removing the first component 2a, the second component 2b, and the third component 2c that have been once installed for some reason, the work can be efficiently performed. Even in the first modification as described above, the same effects as those of the above-described embodiment can be obtained.

[0066] 3. Second Modification Next, a second modification of the broadcast reception antenna device 1 according to the embodiment will be described. FIG. 4 is a top view showing a second modification of the broadcast reception antenna device 1 according to the embodiment.

[0067] Hereinafter, the second modification will be described. In the following description, the differences from the above-described embodiment will be mainly described, and the description of the same matters will be omitted. In FIG. 4, the same matters as those in the above-described embodiment are denoted by the same reference numerals.

[0068] The broadcast reception antenna device 1 shown in FIG. 4 is the same as the above-described embodiment except that two element groups 10 are provided on the substrate 2.

[0069] The broadcast receiving antenna device 1 shown in Fig. 4 has two element groups 10, and thus has two standing wave antennas arranged in parallel. As a result, the broadcast receiving antenna device 1 becomes a so-called stacked antenna. The stacked antenna contributes to enhancing the directivity and operating gain.

[0070] In Fig. 4, the distance between the element groups 10 is denoted as S10-10. The distance S10-10 is the distance between the intermediate lines in the Y-axis direction of the element groups 10. By ensuring that the distance S10-10 is long, the directivity and operating gain of the broadcast receiving antenna device 1 can be enhanced. Specifically, it is preferably (1 / 2)λ or more, and more preferably (3 / 4)λ or more. Specifically, it is preferably 300 mm or more, and more preferably 500 mm or more. Thereby, the directivity and operating gain can be sufficiently enhanced. On the other hand, considering that the broadcast receiving antenna device 1 may become too large and may impair portability and appearance, the upper limit value of the distance S10-10 is preferably 3λ or less, and more preferably 2λ or less. Specifically, it is preferably 1500 mm or less, and more preferably 1000 mm or less.

[0071] Note that the number of stacks of the above-described stacked antenna is 2, but the number of stacks may be 3 or more. That is, the broadcast receiving antenna device 1 may have three or more element groups 10. Even in the second modification as described above, the same effects as those of the above embodiment can be obtained.

[0072] 4. Usage method Since the broadcast receiving antenna device 1 according to the embodiment is plate-shaped and thin, for example, it can be easily carried into and installed in a narrow space. Therefore, the broadcast receiving antenna device 1 can be easily installed in a narrow space such as an attic. Further, since the broadcast receiving antenna device 1 is thin, it can be suppressed that the appearance is impaired or it becomes obstructive after installation.

[0073] The broadcast receiving antenna device 1 is used, for example, for receiving terrestrial digital broadcast waves. As a result, it becomes possible to install a receiving antenna device for terrestrial digital broadcast having high reception sensitivity without impairing the appearance even for a house or the like where the installation location is limited. As a result, television broadcast can be received at a good reception level.

[0074] FIG. 5 is a cross-sectional view showing a state where the broadcast receiving antenna device 1 according to the embodiment is installed in the attic AT of the house H1.

[0075] The house H1 shown in FIG. 5 is an example of a house H1 (building) having an attic AT. The attic AT is a space surrounded by a ceiling CE and a roof RF. Since the attic AT is a space that is not usually visible to the occupants, the appearance is not impaired even if the broadcast receiving antenna device 1 is installed. In addition, the attic AT is a space where the influence of wind and rain, attenuation of broadcast waves by the outer wall, heat insulating windows, and neighboring houses is small. Therefore, by installing the broadcast receiving antenna device 1 in the attic AT, a high radio wave intensity can be stably obtained without impairing the appearance of the house H1. Furthermore, since the attic AT is more accessible than on the roof RF, the installation work of the broadcast receiving antenna device 1 can be easily performed. In addition, since the attic AT is close to the room RO where the occupants live, the laying distance of the antenna wire can be shortened. As a result, the installation work of the antenna wire can be easily performed, and signal attenuation can be suppressed.

[0076] FIG. 6 is a cross-sectional view showing a state where the broadcast receiving antenna device 1 according to the embodiment is installed between the roof RF (structural material) and the waterproof sheet WP of the house H2.

[0077] The house H2 shown in FIG. 6 is an example of a house H2 (building) having a waterproof sheet WP laid on the roof RF. Since the roof RF shown in FIG. 6 has a flat shape, a waterproof sheet WP is usually laid. Therefore, the broadcast receiving antenna device 1 shown in FIG. 6 is installed between the roof RF (structural material) and the waterproof sheet WP.

[0078] Since the broadcast receiving antenna device 1 is thin, even when installed in such a location, the influence on the waterproof property by the waterproof sheet WP can be minimized. On the other hand, since such a location is a location where the attenuation of the broadcast wave is small, it is also a location where a high radio wave intensity can be stably obtained in the broadcast receiving antenna device 1. Note that arbitrary members may be interposed between the roof RF and the broadcast receiving antenna device 1, and between the broadcast receiving antenna device 1 and the waterproof sheet WP, respectively.

[0079] Note that the installation location of the broadcast receiving antenna device 1 is not limited to the above location. The installation location of the broadcast receiving antenna device 1 may be, for example, inside the room RO, inside a structural material such as the roof RF or the ceiling CE, and is not limited to a building. For example, it may be inside or outside a moving body such as an automobile, a train, or a ship.

[0080] 5. Effects achieved by the above embodiment and the modification The broadcast receiving antenna device 1 according to the above embodiment and the modification is a broadcast receiving antenna device corresponding to the reception of radio waves having a frequency of 470 MHz or more and 710 MHz or less, and includes a substrate 2, a radiation element 3 provided on the substrate 2, a reflection element 4 provided on the substrate 2, and a waveguide element 5 provided on the substrate 2. The reflection element 4, the radiation element 3, and the waveguide element 5 are provided so as to be arranged in this order in the X-axis direction (first direction). When the width of the radiation element 3 in the X-axis direction is W3 and the length in the Y-axis direction (second direction orthogonal to the first direction) is L3, the ratio W3 / L3 is 0.10 or more and 0.50 or less.

[0081] According to such a configuration, since the whole has a plate shape, a broadcast receiving antenna device 1 with excellent portability and easy to install in a narrow space can be obtained. In addition, since the shape of the radiation element 3 is optimized, a broadcast receiving antenna device 1 having high reception sensitivity in a wide band can be obtained.

[0082] Further, when the width of the reflection element 4 in the X-axis direction (first direction) is W4 and the length in the Y-axis direction (second direction) is L4, it is preferable that the ratio W4 / L4 is 0.03 or more and 0.20 or less.

[0083] According to such a configuration, a broadcast receiving antenna device 1 having high reception sensitivity can be realized in a sufficiently wide band.

[0084] Further, the distance S3-4 between the radiation element 3 and the reflection element 4 is preferably 60 mm or more and 170 mm or less.

[0085] According to such a configuration, the reflection efficiency of the broadcast wave in the reflection element 4 becomes higher. As a result, the operating gain of the broadcast receiving antenna device 1 can be further increased.

[0086] Further, the constituent material of the substrate 2 is preferably a resin material. According to such a configuration, the weight of the broadcast receiving antenna device 1 can be reduced.

[0087] Further, the substrate 2 may be divided into at least a first component 2a and a second component 2b. According to such a configuration, a broadcast receiving antenna device 1 with excellent portability and easy to install even in a narrow space can be realized.

[0088] Further, the substrate 2 may have an engagement structure 201 for engaging the first component 2a and the second component 2b with each other.

[0089] According to such a configuration, the first component 2a and the second component 2b can be connected with high positional accuracy.

[0090] Further, the broadcast receiving antenna device 1 according to the above embodiment and the modification is installed in the attic AT of the building.

[0091] Since the attic AT is usually a space that is not visible to the residents, even if the broadcast receiving antenna device 1 is installed, the appearance will not be damaged. In addition, the attic AT is a space where the influence of wind and rain, the attenuation of broadcast waves by the outer wall, heat-insulating windows, and neighboring houses is small. Therefore, by installing the broadcast receiving antenna device 1 in the attic AT, a high radio wave intensity can be stably obtained without damaging the appearance of the house H1 (building). Furthermore, since the attic AT is more accessible than the roof RF, the installation work of the broadcast receiving antenna device 1 can be easily performed. Also, since the attic AT is close to the room RO where the residents live, the laying distance of the antenna wire can be shortened. As a result, the installation work of the antenna wire can be easily performed, and signal attenuation can be suppressed.

[0092] Also, the broadcast receiving antenna device 1 according to the embodiment and the modification is installed between the roof RF (structural material) and the waterproof sheet WP of the building.

[0093] Since the broadcast receiving antenna device 1 is thin, even if it is installed in such a place, the influence on the waterproof property by the waterproof sheet WP can be minimized, and the appearance of the house H2 (building) is not easily damaged. On the other hand, since such a place has little attenuation of broadcast waves, a high radio wave intensity can be stably obtained in the broadcast receiving antenna device 1.

[0094] The broadcast receiving antenna device 1 according to the embodiment and the modification includes a radiation element 3, a reflection element 4, and a waveguide element 5, and has a plurality of element groups 10 provided on a substrate 2.

[0095] According to such a configuration, the broadcast receiving antenna device 1 can be a stacked antenna. Thereby, the directivity and the operating gain of the broadcast receiving antenna device 1 can be increased.

[0096] As described above, the broadcast receiving antenna device of the present invention has been described, but the present invention is not limited to the above embodiment and modification.

[0097] For example, the broadcast receiving antenna device of the present invention may have an arbitrary configuration added to the above-described embodiment, such as a protective layer covering each element.

[0098] Further, the substrate included in the broadcast receiving antenna device of the present invention may be dividable into a plurality of parts. Thereby, it is possible to adopt an operation procedure of storing, transporting, etc. in a divided state and assembling at the time of installation, and the work efficiency can be improved.

Example

[0099] Next, specific examples of the present invention will be described. Note that the present invention is not limited to the descriptions of these examples.

[0100] 6. Fabrication of Broadcast Receiving Antenna Device A broadcast receiving antenna device having the configuration shown in Table 1 was fabricated. In Table 1, those corresponding to the present invention are referred to as "Examples", and those not corresponding to the present invention are referred to as "Comparative Examples".

[0101] Note that, as the constituent material of the substrate, PVC (polyvinyl chloride resin) or PET (polyethylene terephthalate) resin was used. Also, for each element, a copper foil with a thickness of 18 μm was used. Also, Examples 12 and 13 are composed of stacked antennas with a stack number of 2.

[0102] Comparative Example 3 is a commercially available Yagi antenna. In this Yagi antenna, each element is composed of an aluminum tube with an outer diameter of 8 mm.

[0103] 7. Evaluation of Broadcast Receiving Antenna Device Next, the fabricated broadcast receiving antenna device was evaluated for the following items.

[0104] 7.1. Evaluation of Gain Radio waves with frequencies of 470 MHz, 500 MHz, 600 MHz, and 700 MHz were received by the broadcast receiving antenna devices of each example and each comparative example, and the maximum gain was measured. The measurement results are shown in Table 1.

[0105] Also, the gain across the entire band was evaluated by comparing each measured value against the following evaluation criteria. The evaluation results are shown in Table 1.

[0106] A: The maximum gain across the entire band is 8 dBi or more. B: The maximum gain across the entire band is 5 dBi or more (excluding cases evaluated as A). C: There is a band with a maximum gain of less than 5 dBi.

[0107] 7.2. Evaluation of Bandwidth For each broadcast receiving antenna device of each example and each comparative example, the standing wave ratio (commonly referred to as VSWR (Voltage Standing Wave Ratio)) was measured. Using the frequency at which the VSWR value is lowest as the peak frequency, when the frequency range where the VSWR is 2.5 or less around the peak frequency is defined as the bandwidth, the ratio bandwidth obtained by dividing the bandwidth by the peak frequency was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.

[0108] A: The ratio bandwidth is 30% or more. B: The ratio bandwidth is 20% or more (excluding cases evaluated as A). C: The ratio bandwidth is less than 20%.

[0109] 7.3. Evaluation of Ease of Installation in a Narrow Space For each broadcast receiving antenna device of each example and each comparative example, the ease of installation in a narrow space was evaluated. Specifically, for each broadcast receiving antenna device, the thickness t2 of the substrate and the total thickness of the device were evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.

[0110] A: The thickness t2 of the substrate or the total thickness of the device is 5 mm or less. B: The thickness t2 of the substrate or the total thickness of the device is more than 5 mm and 10 mm or less. C: The thickness t2 of the substrate or the total thickness of the device is more than 10 mm.

[0111] 7.4. Comprehensive Evaluation For the broadcast reception antenna devices of each example and each comparative example, the above evaluation results were comprehensively evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.

[0112] A: All of the evaluation results of gain, bandwidth, and ease of installation are A. B: At least one of the evaluation results of gain, bandwidth, and ease of installation is A, and the rest are B. C: All of the evaluation results of gain, bandwidth, and ease of installation are B or at least one item is C.

[0113] [Table 1]

[0114] From the results shown in Table 1, the following were found. · By optimizing the ratio W3 / L3 of the length L3 to the width W3 of the radiation element, it was possible to achieve both a wide reception band and a high operating gain. · Since the broadcast reception antenna device of each example is thin, its ease of installation was better than that of a commercially available Yagi antenna. · The stacked antenna had particularly good operating gain.

[0115] From the above results, it was confirmed that according to the present invention, it is possible to realize a broadcast reception antenna device that can be easily installed even in a narrow space and has high reception sensitivity in a wide reception band. [Explanation of Reference Numerals]

[0116] 1 Broadcast reception antenna device 2 Substrate 2a First component 2b Second component 2c Third component 3 Radiation element 3a Element conductor 3b Element conductor 4 Reflector 5 Waveguide element 5a element conductor 5b element conductor 5c element conductor 5d element conductor 5e element conductor 5f element conductor 5g element conductor 5h element conductor 5i element conductor 5j element conductor 5k element conductor 5L element conductor 10 element group 21 lower surface 22 upper surface 22a upper surface 22b upper surface 22c upper surface 25 engaging part 35A engaged part 35B engaging part 45 engaged part 201 engaging structure 202 engaging structure AT attic CE ceiling H1 house H2 house L2 length L3 length L4 length L5 length S3-4 interval S3-5 interval S5-5 interval S10-10 interval RF roof RO room WP waterproof sheet W2 width W3 width W4 width W5 width t2 thickness t3 thickness

Claims

1. A broadcast receiving antenna device corresponding to reception of radio waves having a frequency of 470 MHz or higher and 710 MHz or lower, a substrate, a radiating element provided on the substrate, a reflecting element provided on the substrate, a waveguide element provided on the substrate, and having, the reflecting element, the radiating element, and the waveguide element are provided so as to be arranged in this order in a first direction, when the width of the radiating element in the first direction is W3 and the length in a second direction orthogonal to the first direction is L3, the ratio W3 / L3 is 0.10 or more and 0.50 or less. A broadcast receiving antenna device characterized by that.

2. The broadcast receiving antenna device according to claim 1, wherein when the width of the reflecting element in the first direction is W4 and the length in the second direction is L4, the ratio W4 / L4 is 0.03 or more and 0.25 or less.

3. The broadcast receiving antenna device according to claim 1 or 2, wherein the distance between the radiating element and the reflecting element is 60 mm or more and 170 mm or less.

4. The broadcast receiving antenna device according to claim 1 or 2, wherein the constituent material of the substrate is a resin material.

5. The broadcast receiving antenna device according to claim 1 or 2, wherein the substrate is divided into at least a first component and a second component.

6. The broadcast receiving antenna device according to claim 5, wherein the substrate has an engaging structure for engaging the first component and the second component with each other.

7. The broadcast receiving antenna device according to claim 1 or 2, which is installed in the attic of a building.

8. The broadcast receiving antenna device according to claim 1 or 2, which is installed between a structural material of a building and a waterproof sheet.

9. The broadcast receiving antenna device according to claim 1 or 2, comprising a plurality of element groups composed of the radiation element, the reflection element, and the waveguide element and provided on the substrate.

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