JP2006270494A - Antenna and television receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suitable indoor antenna for a receiver such as a thin television receiver by making the antenna of a broad band, a thin-thickness and a small size. <P>SOLUTION: A ground plate used also as a shield plate arranged in a receiver case 11 is used as one radiation panel 21. The other radiation panel 31 is arranged on the upper side face of the casing 11 outside of the casing. The radiation panel 31 has a plane conical shape, and its vertex is made to face the upper edge 22 of the radiation panel 21 with a small gap. The vertex part of the radiation panel 31 and a place on the upper edge 22 of the radiation panel 21 opposing this are made to be power feeding points. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an antenna used as an indoor antenna of a receiver such as a flat-screen television receiver that receives UHF band television broadcasting such as terrestrial digital broadcasting, and a television receiver equipped with the antenna.

  Conventionally, most of the indoor antennas for television receivers for receiving UHF band television broadcasts are simple loop antennas.

  However, the loop antenna is structurally narrow, and it is difficult to obtain a sufficient antenna gain and a low voltage standing wave ratio (VSWR) over a wide band. Even if it can be realized, the antenna part becomes a structure that protrudes outward from the receiver, which impairs the design.

  In order to obtain a sufficient antenna gain over a wide band, a three-dimensional structure such as a so-called Yagi structure may be considered, but in this case, a balance with a thin television receiver using a flat display panel such as a liquid crystal display is possible. Is not suitable for indoor antennas.

  Another example of a broadband antenna is a conical antenna. For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-201261), a conical depression is formed on one end face of a dielectric, a radiation electrode is provided on the surface of the depression, and the other end faces the one end face of the dielectric. A monoconical antenna is shown in which a ground conductor is provided close to and substantially parallel to the end face, and power is fed between the apex portion of the radiation electrode and the ground conductor portion.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 11-31918) discloses a pair of fan-shaped conductor patches as a microwave millimeter-wave radiation type oscillation device in which an electromagnetic wave radiation function and a high-frequency oscillation function as an antenna are integrated. Arranged so that the respective central portions are close to each other and the respective arc portions face each other, a field effect type high-frequency transistor is connected to the pair of fan-shaped conductor patches, and a conductor plane is disposed in parallel with the pair of fan-shaped conductor patches. Things are shown.

The prior art documents listed above are as follows.
JP 2004-201261 A JP 11-31918 A

  However, a conical antenna (monoconical antenna) as shown in Patent Document 1 has a three-dimensional structure, and thus is not well balanced with a thin television receiver and is not suitable as an indoor antenna.

  Therefore, the present invention can be made wide and thin and small, and is suitable as an indoor antenna of a receiver such as a thin television receiver.

The antenna of this invention is
A first radiation plate that is arranged in the receiver housing or is a ground plate that constitutes the receiver housing;
A planar conical second radiating plate disposed at an apex portion facing one side edge of the first radiating plate;
The apex portion of the second radiation plate and the portion on the one side edge of the first radiation plate facing the second radiation plate are feed points.

  The antenna of the present invention having the above-described configuration uses a ground plate disposed in or constituting the receiver casing as the first radiating plate as a part of the antenna radiator. Since a planar conical shape is used as the second radiation plate as the remainder of the radiator, the entire antenna can be made thin, and the second conical shape outside the receiver casing is present. (However, the second radiation plate can also be arranged in the receiver housing.) The apparent antenna portion can be reduced in size, and a flat-screen television receiver such as a liquid crystal television receiver can be used. Matches the machine and can be easily carried with a television receiver.

  In addition, since the second radiation plate has a planar conical shape, sufficient antenna gain can be obtained over a wide band, and in combination with the use of a ground plate as the first radiation plate, Manufacturing is facilitated and costs can be reduced.

  As described above, according to the present invention, it is possible to make a broadband, thin and small size, and it is suitable as an indoor antenna of a receiver such as a thin television receiver.

  1 and 2 show an example of a television receiver provided with the antenna of the present invention. FIG. 1 is a diagram seen from the front, and FIG. 2 is a diagram seen from the back with the rear housing removed.

  In the television receiver of this example, the liquid crystal display 15 is accommodated in the receiver casing 11 as a whole so as to face the front from the window of the front frame 12 of the receiver casing 11, and in FIGS. Although omitted, a circuit device including a printed circuit board and circuit elements mounted thereon is disposed behind the liquid crystal display 15, and the following antenna is mounted inside and outside the receiver housing 11. A stand 19 is attached.

  The antenna of this example is constituted by two radiation plates (radiators) 21 and 31 having different sizes. As the larger radiation plate 21, a ground plate that also serves as a shield plate disposed behind the circuit device in the receiver housing 11 is used.

  The smaller radiation plate 31 is formed in a planar conical shape as described later by a conductive thin plate such as a copper foil sheet having a thickness of several mm, and is fixed to the back surface of the holding plate 39 made of an insulating plate, for example, It arrange | positions so that the radiation plate 21 and the substantially same surface may be formed in the exterior of the receiver housing | casing 11, for example, on the upper surface of the receiver housing | casing 11. FIG.

  Alternatively, when a printed circuit board is used, the radiation plate 31 and the holding plate 39 can be used, and the target antenna can be realized at low cost. Further, as another form, by integrating the radiation plate 31 and the holding plate 39, or a printed circuit board that serves as both, with the receiver housing 11 by bulging the upper portion of the receiver housing 11, The entire receiver can be refreshed by design.

  As shown in FIG. 2, the apex of the radiation plate 31 and the upper edge 22 of the radiation plate 21 are opposed to each other with a gap as will be described later, and the apex of the radiation plate 31 and the apex. A portion on the upper edge 22 of the radiation plate 21 is a feeding point.

  For example, the coaxial line 41 is used as an antenna feed line, and one end of the copper foil 45 for connection is soldered to a portion to be a feed point on the upper edge 22 of the radiation plate 21. The inner conductor (core wire) 42 in the section is connected to the apex portion of the radiation plate 31 by solder 46, and the outer conductor (outer skin) 43 in one end portion of the coaxial line 41 is connected to the other end of the copper foil 45 by solder 47. The other end portion of the coaxial line 41 omitted in FIG. 2 is connected to the receiver tuner portion omitted in FIG.

  By adopting such a power feeding structure and a support structure, the holding plate 39 or the printed circuit board to which the radiation plate 31 is attached is supported on the upper side surface of the receiver casing 11 or the receiver casing 11 Can be arranged.

  As shown in FIG. 3, when the horizontal direction of the receiver is the X-axis direction, the vertical direction is the Y-axis direction, and the front-rear direction (the direction perpendicular to the plane of the radiation plates 21 and 31) is the Z-axis direction, The directivity characteristic of the antenna 31 is as shown in FIGS. However, the centers of these characteristic diagrams are the feeding points 24 and 34 shown in FIG.

  As is clear from FIGS. 4 and 5, the antenna is almost omnidirectional with respect to the horizontal direction. Therefore, it is possible to freely arrange the thin television receiver on any desired wall without worrying about the mounting direction of the radiation plate 31 and the receiver housing 11.

  FIG. 6 shows an example of the shape, size, and arrangement of the radiation plates 21 and 31. The shape of the radiation plate 21 also serving as the ground plate may be a square or a rectangle, but in the case of an antenna that receives a UHF band television broadcast, the size (area) of the radiation plate 21 is a square. In this case, a size (area) of about 200 mm × 200 mm is required.

  The radiation plate 31 has a planar conical shape as described above. The planar conical shape is a planar shape (flat plate shape) and has a vertex formed by intersecting two oblique sides with an inner angle smaller than 180 degrees.

  The example of FIG. 6 is a case where the radiation plate 31 has a substantially sector shape in which the semicircular portion 33 is integrated with the base 32c side of the isosceles triangular portion 32. That is, the radiation plate 31 of this example has a fan shape in that the outer shape is formed by the two oblique sides 32a and 32b that form the apex portion 34 and the curved side 33c that protrudes outward (upper side). If what is generally called a fan shape is a part of a circle and the inner angle is smaller than 180 degrees, the radiation plate 31 in this example has a curved side 33c that bulges outward (upward) from the fan shape. Shape.

  Thus, by making the radiation plate 31 have a convex curved side 33c, a sufficient antenna gain and a low voltage standing wave ratio (VSWR) can be obtained over a wide band, and the ripple in the band can be reduced. Can be suppressed.

  As will be described later, the inclination angle (angle relative to the upper edge 22 of the radiation plate 21) θ of the oblique sides 32a and 32b of the radiation plate 31 and the gap (distance) between the apex 34 of the radiation plate 31 and the upper edge 22 of the radiation plate 21. ) D affects the characteristics as an antenna.

  In FIG. 6, α is an internal angle formed by the hypotenuse 32a and the hypotenuse 32b, represented by α = 180 degrees −2θ, r is the radius of the semicircular portion 33, and h is It is the height of the isosceles triangle portion 32 represented by h = r × tan θ. The part 24 is a feeding point on the upper edge 22 of the radiation plate 21.

  The inclination angle θ is preferably in the range of 15 degrees ≦ θ ≦ 45 degrees, and is most preferably around 30 degrees. The gap d is preferably within a range of 5 mm ≦ d ≦ 15 mm, and particularly preferably around 10 mm.

  The characteristics of the antenna were examined by computer / electromagnetic simulation under the following conditions. The radiation plate 21 is a square of 200 mm × 200 mm, and the radiation plate 31 is formed by integrating an isosceles triangular portion 32 and a semicircular portion 33, and the radius r of the semicircular portion 33 is 50 mm. The height h of the isosceles triangle portion 32 changes according to the inclination angle θ as described above, and is 50 mm × 0.577 = 28.85 mm when θ = 30 degrees.

  The gap d is set to 10 mm, the inclination angle θ is set to three types of 15 degrees, 30 degrees, and 45 degrees, the characteristics are examined, the inclination angle θ is set to 30 degrees, and the gap d is set to three types of 5 mm, 10 mm, and 15 mm. The characteristics were investigated. 7 to 12 show the antenna characteristics of the simulation results.

  FIG. 7 shows the case of d = 10 mm and θ = 15 degrees, the curve 5R shows the return, the curve 5L shows the loss, the curve 5V shows the voltage standing wave ratio (VSWR), and the curve 5M. Indicates the input impedance (Z-input).

  FIG. 8 shows the case of d = 10 mm and θ = 30 degrees. Curve 6R represents return, curve 6L represents loss, curve 6V represents voltage standing wave ratio (VSWR), and curve 6M. Indicates the input impedance (Z-input).

  FIG. 9 shows a case where d = 10 mm and θ = 45 degrees. Curve 7R represents reflection, curve 7L represents loss, curve 7V represents voltage standing wave ratio (VSWR), and curve 7M. Indicates the input impedance (Z-input).

  FIG. 10 shows the case of θ = 30 degrees and d = 5 mm, the curve 8R represents the return, the curve 8L represents the loss, the curve 8V represents the voltage standing wave ratio (VSWR), and the curve 8M. Indicates the input impedance (Z-input).

  FIG. 11 shows the case of θ = 30 degrees and d = 10 mm. Curve 9R shows reflection, curve 9L shows loss, curve 9V shows voltage standing wave ratio (VSWR), curve 9M. Indicates the input impedance (Z-input).

  FIG. 12 shows the case of θ = 30 degrees and d = 15 mm, the curve 10R represents the return, the curve 10L represents the loss, the curve 10V represents the voltage standing wave ratio (VSWR), and the curve 10M. Indicates the input impedance (Z-input).

  From the above results, when the inclination angle θ is viewed, the inclination angle θ is small as shown in FIG. 7 (in the case of θ = 15 degrees), and between the oblique sides 32a and 32b of the radiation plate 31 and the upper edge 22 of the radiation plate 21. When the gap is narrow, the inclination angle θ is an intermediate angle as shown in FIG. 8 (when θ = 30 degrees), and the gap between the oblique sides 32a and 32b of the radiation plate 31 and the upper edge 22 of the radiation plate 21. Is an intermediate width, or the inclination angle θ is large as shown in FIG. 9 (when θ = 45 degrees), and the gap between the oblique sides 32a and 32b of the radiation plate 31 and the upper edge 22 of the radiation plate 21 is large. Compared with the case where the width is large, the loss is increased by about 0.3 dB, and the return is not optimal.

  Conversely, when the inclination angle θ is large as shown in FIG. 9 (when θ = 45 degrees) and the gap between the oblique sides 32a and 32b of the radiation plate 31 and the upper edge 22 of the radiation plate 21 is wide, FIG. The inclination angle θ is small as in the case of θ = 15 degrees, and the gap between the oblique sides 32a and 32b of the radiation plate 31 and the upper edge 22 of the radiation plate 21 is narrow, or FIG. As compared with the case where the inclination angle θ is an intermediate angle and the gap between the oblique sides 32a and 32b of the radiating plate 31 and the upper edge 22 of the radiating plate 21 is an intermediate width as shown in FIG. Thus, the voltage standing wave ratio (VSWR) is slightly deteriorated. Therefore, the inclination angle θ is optimally about 30 degrees.

  On the other hand, regarding the gap d, if the gap d is small as shown in FIG. 10 (when d = 5 mm), the gap d is an intermediate size as shown in FIG. 11 (when d = 10 mm), or Compared with the case where the gap d is large as shown in FIG. 12 (when d = 15 mm), the return is not optimal, and conversely, when the gap d is large as shown in FIG. 12 (when d = 15 mm). Compared to the case where the gap d is small as shown in FIG. 10 (when d = 5 mm) or the gap d is intermediate as shown in FIG. 11 (when d = 10 mm), the voltage is around 700 MHz. The standing wave ratio (VSWR) is slightly deteriorated. Therefore, the gap d is optimally about 10 mm.

  The example described above is a case where a ground plate disposed in the receiver housing 11 is used as the radiation plate 21 having a large area. However, when a part or all of the receiver housing is a ground plate, The receiver casing itself can be used as a radiation plate having a large area.

  Moreover, although the example mentioned above is a case where a thin television receiver is provided with the liquid crystal display 15, as a thin television receiver, it is provided with other flat panel displays, such as a plasma display and an organic EL display. But you can.

It is the figure seen from the front of an example of a television receiver provided with the antenna of this invention. It is the figure seen from the back surface of the television receiver of FIG. It is a figure where it uses for description of the directivity of an antenna. It is a figure which shows the directivity characteristic of an antenna. It is a figure which shows the directivity characteristic of an antenna. It is a figure which shows the example of the shape of two radiation plates, a magnitude | size, and arrangement | positioning. It is a figure which shows the antenna characteristic of a simulation result. It is a figure which shows the antenna characteristic of a simulation result. It is a figure which shows the antenna characteristic of a simulation result. It is a figure which shows the antenna characteristic of a simulation result. It is a figure which shows the antenna characteristic of a simulation result. It is a figure which shows the antenna characteristic of a simulation result.

Explanation of symbols

  Since all the main parts are described in the figure, they are omitted here.

Claims (4)

A first radiation plate that is arranged in the receiver housing or is a ground plate that constitutes the receiver housing;
A planar conical second radiating plate disposed at an apex portion facing one side edge of the first radiating plate;
An antenna in which the apex portion of the second radiation plate and a portion on the one side edge of the first radiation plate facing the second radiation plate are feed points. The antenna of claim 1.
The antenna according to claim 1, wherein the second radiation plate has two oblique sides forming the apex portion and an outwardly convex curved side connecting the two oblique sides.   A television receiver comprising the antenna according to claim 1.   The television receiver according to claim 3, comprising a flat display panel.

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