JP3575012B1 - Broadband antenna element and wideband indoor antenna - Google Patents

Abstract

Provided is an antenna element for receiving a radio wave of a frequency over a wide band with a simple structure, and a small-sized indoor antenna to which the antenna element is applied and which can be easily installed in a room.
The conductive plate includes a conductive plate formed in a quadrilateral shape, and an opening which is located substantially at the center of the conductive plate and has a shape in which a distance between edges facing each other gradually increases or decreases. It has a cutout hole 3, a communication hole 4 connected to the cutout hole 3 and opened to reach one side of the conductor plate 2, and a pair of feed points 5 provided in the vicinity of the communication hole 4. The electric wave received by the conductor plate 2 is supplied to the feed point 5 as an electric signal.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an antenna element and an indoor antenna particularly suitable for receiving radio waves in the UHF band or the like.
[0002]
[Prior art]
This type of antenna, particularly a slot antenna for transmitting or receiving radio waves in a high frequency band, is used in communication equipment. The slot antenna is provided with a slot in a conductive plate made of a metal plate or the like having good conductivity, and the shape of the slot is determined based on a dimension derived from a wavelength of a radio wave frequency to be used. For example, assuming that the wavelength of the radio wave to be used is λ, the opening length of the slot is set to λ / 2, λ / 4, or the like (for example, see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. H11-186836
[Problems to be solved by the invention]
However, in the conventional antenna having a slot, since the size of the slot is determined according to the wavelength λ of the radio wave to be used, it has been difficult to apply the antenna to an application having a wide frequency band.
[0005]
The present invention has been made in view of the above-described problems of the conventional technology, and provides an antenna element capable of receiving radio waves of a wide frequency band with a simple structure as compared with a conventional antenna. It is another object of the present invention to provide a small-sized indoor antenna to which this antenna element is applied and which can be easily installed in a room.
[0006]
[Means for Solving the Problems]
According to the present invention, the above-mentioned problem is solved as follows.
[0007]
(1) A conductive plate formed in a quadrilateral shape, and edges located substantially at the center of the conductive plate and having one center line of the quadrilateral as a symmetry axis and facing each other with the symmetry axis interposed therebetween. The distance between the portions gradually increases toward the center of the quadrilateral, and two wedge shapes having different axial lengths from each other, and a parallel portion connecting in parallel the portions where the widened portions of both wedge shapes face each other, And a cutout hole formed of a side portion having a truncated corner perpendicular to the axis and a wedge-shaped narrow portion having a shorter length in the axial direction. In the width portion, a corner portion is truncated perpendicular to the axis, and both ends of the truncated side portion are extended along the symmetry axis to a communication hole extending in parallel until reaching one side of the conductor plate. By providing a pair of feeding points provided respectively near the communication hole.
[0008]
(2) The length and width of the conductor plate are 200 mm and the thickness is 0.1 mm, respectively. The length of one wedge in the axial direction is 84 mm, the length of the widened portion is 88 mm, and the width of the narrowed portion is 88 mm. The length of the truncated side was 12 mm, the length of the other wedge in the axial direction was 54 mm, the length of the widened portion was 88 mm, and the length of the truncated side in the narrow portion was 10 mm. The width of the parallel portion connecting the wedge-shaped widened portion is 88 mm, the length in the axial direction is 12 mm, and the width of the communication hole connecting the shorter side of the wedge shape and one side of the conductor plate is 10 mm, The length was 40 mm.
[0009]
(3) A leg fixed vertically upward from a support table arranged on the floor, and the legs are supported by the legs in a plate-like shape with the plate surface oriented horizontally. and a plate-shaped support portion, the support member is an electrically conductive conductor plate formed in a quadrilateral, and located in the center of the conductive plate, one of the center line of a quadrilateral symmetrical axis The distance between the edges facing each other across the axis of symmetry gradually increases toward the center of the quadrilateral, and the two wedge shapes having different axial lengths, and the widened portions of the two wedge shapes A parallel portion connecting the facing portions in parallel, and a wedge-shaped narrow portion having a longer length in the axial direction, a cutout hole formed by a side portion having a truncated corner perpendicular to the axis, and an axis. In the narrow part of the wedge shape with the shorter length in the direction, the corner is truncated perpendicular to the axis, It has a communication hole extending in parallel at both ends of the truncated side portion until it reaches one side of the conductor plate along the axis of symmetry, and a pair of feeding points respectively provided near the communication hole. By holding the antenna element in a predetermined position and shape.
BEST MODE FOR CARRYING OUT THE INVENTION
[0010]
FIG. 1 shows an antenna element (1) according to a first embodiment of the present invention.
The antenna element (1), the conductor plate of conductivity formed in a quadrilateral and (2), located approximately in the center of the conductive plate (2), one of the center line of the quadrilateral (X-X) Is the axis of symmetry (xx), and the distance between the edges (3a) and (3a) , (3b) and (3b) facing each other with the axis of symmetry (xx) toward the center And the two fan-shaped shapes ( 3A ) and ( 3B ) having different distances (L a ) and (L b ) in the direction of the symmetry axis (xx ) , and the widening of both wedge shapes ( 3A ) and ( 3B ) . parallel portion in parallel to connect the central portion section is opposed (3C), and the symmetry axis (x-x) at the narrow portion of the direction of the distance (L a) is longer wedge shape (3A), symmetry axis ( x-x) perpendicular to truncated sides that truncated corners in a (cut-out hole made of 6a) (3), the symmetry axis (x-x) direction of the distance (L b) is shorter wedge the narrow portion of (3B) There are, perpendicular to the axis of symmetry (x-x) of the corner was truncated, the truncated side portions at both ends of the (6b), the lower axis of symmetry said conductor plate along (x-x) (2) includes a communication hole extending in parallel to reach the horizontal side (2a) of (4), and a pair of feed points respectively provided in the vicinity of sandwiching the communication hole (4) (5) (5) I have.
[0011]
The conductive plate (2) can be realized by a metal plate having good conductivity, and the metal plate is preferably made of a metal plate such as copper, aluminum, brass, and stainless steel. The thickness of the conductor plate (2) is 0.1 mm in the present embodiment. Also in the embodiments, the conductive plate (2) is a vertical side (2b) and the length of the lateral side (2a) (H) and (W) has both a positive square 200 mm.
[0012]
The cutout hole (3) has a slightly vertically elongated wedge shape ( 3A ) , a lower wedge shape ( 3B ) , and a parallel portion ( 3C ) connected in the center along the symmetry axis (xx). Is formed in the shape of a rhombus. The horizontal width (a) of the parallel portion ( 3C ) at the center is 88 mm, and the vertical width (3A) of the upper and lower wedges ( 3A ) ( 3B ) is the distance between the truncated sides (6a) (6b). b) is 150 mm, and the length 150 mm of the vertical width (b) is based on the center of the vertical side (2b) which forms the other center line (YY ) of the conductor plate (2) . The length is set to 90 mm upward in the drawing and 60 mm downward in the drawing. Similarly, the center of the width of the parallel portion of the cut-out hole (3) (3C) (a), the conductive plate central horizontal side of (2a) in (2), i.e. the center line (X-X) and the line of symmetry ( xx), and the length (88 mm) of the width (a) is set to be 44 mm left and right with respect to the center.
[0013]
Cut-out hole (3), as described above, to form a wedge shape (3A) (3B), has four edges and (3a) (3a) (3b) (3b), these wedge-shaped ( The edges (3a) and (3a) of 3A ) are arranged so that the distance between them gradually increases along the axis of symmetry (xx) from the top to the bottom of the drawing and away from each other. I have. Also, edge portions of the wedge-shaped (3B) (3b) (3b ) to each other are arranged so that their spacing toward the center of the upper from below moves away gradually increases. Thus, two opposed wedge shapes ( 3A ) and ( 3B ) are formed by these four edges (3a) (3a) (3b) (3b) . Further, the corner portion when the cut-out hole (3) is the opening of the substantially rhombic, each corner in a way that truncated, truncated side portions corresponding to both sides portions of the parallel portion (3C) ( 6c) and (6c), the three truncated sides of the narrow portion of the wedge-shaped (3A) and (6a), cut-out hole angle side (6) (6) (6) is provided. In this embodiment, the length of the cutout hole corner (6) is 12 mm. As a result, the distance (L a ) in the direction of the symmetry axis (xx ) of the upper wedge shape ( 3A ) is 84 mm, and the distance (L a ) in the direction of the symmetry axis (xx ) of the lower wedge shape ( 3B ). b ) is 54 mm.
[0014]
One corner which remains in the substantially rhombic, i.e. the narrow portion of the wedge-shaped (3B) of the lower, truncated sides formed by truncated the corners at both ends of the (6b), the symmetry axis (x- A communication hole (4) extending in parallel until reaching the horizontal side (2a) below the conductor plate ( 2 ) along x) is connected. The communication hole (4) is provided continuously from the opening of the cutout hole (3), and reaches the side (2a). The width (c) of the communication hole at the portion where the communication hole (4) reaches the side (2a ) is 10 mm. Feeding points (5) and (5) are provided on the conductor plate (2) near the communication hole (4), and a signal output when the antenna element (1) receives a radio wave and converts it into an electric signal. Make up the terminals.
[0015]
FIG. 2 is a table showing the results of reception of radio waves with horizontal polarization by the antenna element (1). As a receiving condition, a standard dipole antenna was used as a comparison object, and the receiving environment was performed in an anechoic chamber. As for the transmission radio wave, a signal generated by an oscillator is transmitted by a transmitter. In this table, from the left column, in order from the left column, a frequency allocation channel (CH), a frequency for each channel (unit: MHz), reception sensitivity by a standard dipole antenna (unit: dB), and an antenna element (1 ) Shows the receiving sensitivity (unit is dB), and the gain difference (unit is dB) between the standard dipole antenna and the antenna element (1).
[0016]
In this table, the results of eight representative channels of 13, 20, 27, 34, 41, 48, 55, and 62 are shown, and the TV of the UHF band is used as an example for the antenna element (1). Measuring reception sensitivity. For example, in the reception of a horizontally polarized wave of 473 MHz, which is a frequency corresponding to 13 channels, of a TV broadcast wave in the UHF band, the standard dipole antenna to be compared is 68 dB, whereas the gain of the antenna element (1) is (Gain) is 67 dB. Therefore, the gain difference between the two is -1 dB.
[0017]
Similarly, the respective gain differences from the 20th channel to the 62nd channel are −1 dB, 0 dB, −2 dB, 1 dB, −1 dB, −3 dB, and 1 dB, respectively. From this measurement result, it can be seen that the reception sensitivity of the antenna element (1) with the horizontally polarized wave is almost the same as the reception sensitivity of the standard dipole antenna.
[0018]
FIG. 3 is a table showing the results of reception of a vertically polarized radio wave by the antenna element (1). As shown in FIG. 2, the table shown in FIG. 3 shows, in order from the left column, frequency allocation channels (CH), frequencies for each channel (unit: MHz), reception sensitivity by a standard dipole antenna (unit: dB), and this embodiment. 2 shows the reception sensitivity (unit is dB) of the antenna (1) and the gain difference (unit is dB) between the standard dipole antenna and the antenna element (1) according to the embodiment.
[0019]
In this table, the results for channels 13, 20, 27, 34, 41, 48, 55, and 62 are shown in the same manner as in FIG. 2, and the reception of the antenna element (1) is described using a TV broadcast in the UHF band as an example. The sensitivity is being measured. For example, in the case of receiving 473 MHz horizontally polarized wave which is a frequency corresponding to 13 channels, the standard dipole antenna to be compared is 68 dB, whereas the gain of the antenna element (1) is 63 dB. Therefore, the gain difference between the two is -5 dB.
[0020]
Similarly, the respective gain differences from the 20th channel to the 62nd channel are 2 dB, −3 dB, 2 dB, 2 dB, −3 dB, 2 dB, and −1 dB, respectively. From this measurement result, the reception sensitivity of the antenna element (1) in the vertical polarization is almost the same as the reception sensitivity of the standard dipole antenna, similarly to the reception of the radio wave by the horizontal polarization.
[0021]
4 to 6 show standing wave ratio characteristics drawn based on a standing wave ratio (VSWR: Voltage Standing Wave Ratio) of the antenna (1) under the condition of receiving radio waves in a band from 470 MHz to 770 MHz. Curves (7), (8), (9) and (10) are shown. Generally, as a criterion for performance evaluation of an antenna, a standing wave ratio specific to an antenna to be evaluated is measured and expressed as a numerical value, and the performance of the antenna is evaluated by comparing these numerical values. Therefore, in order to evaluate the performance of the antenna (1) of the present invention, the standing wave ratio was measured.
[0022]
4 to 6, the standing wave ratio characteristic curve (7) shows the measurement result of the standing wave ratio of the antenna element (1). Compared with the standing wave ratio characteristic curve (7), the standing wave ratio characteristic curve (8) shows an increase in the standing wave ratio in a relatively low frequency band near 470 MHz. The standing wave ratio characteristic curve (8) is a measurement result of the standing wave ratio when the thickness of the conductor plate (2) of the antenna element (1) is 3 mm instead of 0.1 mm.
[0023]
From this result, it is understood that the standing wave ratio in a low frequency band is improved as the thickness of the conductor plate (2) is reduced. Although the conductor plate (2) according to the first embodiment has a thickness of 0.1 mm, it may have a smaller thickness. For example, a conductor plate formed by etching on a substrate, or a thin film formed by printing, vapor deposition, or the like. A conductor plate may be formed.
[0024]
A standing wave ratio characteristic curve (9) shown in FIG. 5 is a standing wave ratio characteristic curve of the antenna element (1) when the length ( W ) of the horizontal side (2a ) is 16 cm (WL). In this case, as in the case of FIG. 4, the standing wave ratio increases significantly in a relatively low frequency band toward 470 MHz. Since the thickness of the conductor plate (2) remains at 0.1 mm, the contribution to the standing wave ratio characteristic curve in the low frequency band is at least the length (W ) of the side ( 2a) of the conductor plate (2). ) Has a lot to do.
[0025]
A standing wave ratio characteristic curve (10) shown in FIG. 6 is a standing wave ratio characteristic curve of the antenna element (1) when the length ( W ) of the horizontal side (2a) is set to 32 cm (WH). In this case, as in the case of FIG. 4, the standing wave ratio increases significantly in a relatively low frequency band toward 470 MHz. Further, the deterioration of the standing wave ratio is observed even when compared to the standing wave ratio characteristic curve (9) shown in FIG. 5 and toward the relatively high frequency band of the 770 MHz band. From this, the contribution rate to the standing wave ratio characteristic curve in the UHF band is at least largely influenced by the length ( W ) of the horizontal side ( 2a) of the conductor plate (2).
[0026]
FIG. 7 is a perspective view of a wideband indoor antenna (11) according to a second embodiment of the present invention. The indoor antenna (11), a support base arranged on the floor (15) than the fixed vertically upward the legs (14), said legs toward the plate surface in a horizontal direction (14) And a plate-shaped support member (12) integrally formed in a plate shape and supported by its legs (14) . The support member (12) moves the antenna element ( 1 ) to a predetermined position and shape. A wideband indoor antenna that holds and thus enables reception of radio waves indoors.
[0027]
The antenna element (1) is held by a mold member (13) inside the support member (12). In order to hold the antenna element (1) at a predetermined position, the entire support member (12) is manufactured by resin molding or the like instead of the mold member (13) , and the antenna element (1) is simultaneously embedded in the molding process. May be. Since the indoor antenna (11) is independent on the floor by the support base (15) and the legs (14), it can be installed, for example, behind or near a TV set installed indoors. it can. In addition, by designing the outer shape of the plate-shaped radio wave receiving section incorporating the antenna element ( 1 ) in another shape, it is possible to form the indoor antenna (11) having a good design.
[0028]
Provided the feeding point to the conductive plate (2) to (5) (5), feed line (16) (16) is connected to the end (not shown) of the feed line (16) (16) A TV receiver or the like is connected. Instead of using two feed lines (16) and (16) , a high-frequency coaxial cable may be used. In this case, if the impedance of the coaxial cable is 75 ohms, good impedance matching with the antenna element (1) can be maintained. Good impedance matching can prevent the standing wave ratio from deteriorating.
[0029]
Although the length of the communication hole width (c) of the antenna element (1) is set to 10 mm, impedance matching with a coaxial cable can be adjusted by adjusting the width. When the communication hole width (c) is 10 mm, the impedance becomes approximately 75 ohms. Therefore, a coaxial cable can be connected without using an impedance matching device.
[0030]
【The invention's effect】
(A) According to the first aspect of the present invention, the cutout hole provided in the thin conductor is formed into two wedges facing each other via a parallel portion with the widened portion facing the center, and the cutout holes in the axial direction of the two wedges are formed. By making the length different, and by providing a narrow communication hole with a parallel width connecting the cutout hole and the outer periphery of the conductor, it is possible to receive a radio wave of a frequency over a wide band, and improve the wide band characteristic, Moreover, it is possible to provide an antenna element having a simple structure, a small size , and easy installation.
[0031]
(B) According to the second aspect of the present invention, the standing wave ratio characteristic can be kept good in a wide frequency range of 13 to 62 channels of the television frequency, and the impedance matching with the coaxial cable can be performed well. An antenna element can be provided.
[0032]
(C) According to the third aspect of the invention, it is possible to receive a radio wave of a wide band frequency with a simple structure, and it is small in shape, and the radio wave receiving unit can be formed in a plate shape integrally with the leg, so that it can be placed on the floor. A broadband indoor antenna that can be installed independently and easily installed can be provided.
[Brief description of the drawings]
FIG. 1 is a front view for explaining an antenna according to a first embodiment of the present invention.
FIG. 2 is a table showing reception sensitivity of the antenna according to the first embodiment of the present invention in vertical polarization.
FIG. 3 is a table showing reception sensitivity of the antenna according to the first embodiment of the present invention in horizontal polarization.
FIG. 4 is a table showing a comparison of standing wave ratio characteristic curves of the antenna according to the first embodiment of the present invention.
FIG. 5 is a table showing a comparison of standing wave ratio characteristic curves of the antenna according to the first embodiment of the present invention.
FIG. 6 is a table showing a comparison of standing wave ratio characteristic curves of the antenna according to the first embodiment of the present invention.
FIG. 7 is a perspective view of an antenna according to a second embodiment of the present invention.
[Explanation of symbols]
(1) Antenna
(2) Conductor plate
(2a) Side
(2b) Vertical side
(3) Cutout hole
( 3A ) ( 3B ) wedge shape
( 3C ) Parallel part
(3a) (3b) Edge
(4) Communication hole
(5) Feeding point
(6) Square corner of cutout hole
(6a) (6b) (6c) Truncated side
(7) (8) (9) (10) Standing wave ratio characteristic curve
(11) Antenna
(12) Support section
(13) Mold member
(14) Leg
(15) Support base
(16) Feed line
(H) Length of vertical side
(W) Length of side
(a) Width
(b) Vertical width
(c) Communication hole width
Center line (XX)
Center line (Y-Y)
Symmetry axis (xx)

Claims (3)

A conductive conductor plate formed in a quadrilateral, and one center line of the quadrilateral, which is located at substantially the center of the conductor plate, has a center line as a symmetry axis, and the edges facing each other with the symmetry axis interposed therebetween. The distance gradually increases toward the center of the quadrilateral, and two wedge shapes having different axial lengths from each other, and a parallel portion connecting in parallel the portions where the widened portions of the two wedge shapes face each other, and an axial direction In the wedge-shaped narrow portion having a longer length, a cutout hole formed of a side portion having a truncated corner perpendicular to the axis and a wedge-shaped narrow portion having a shorter length in the axial direction. A communication hole extending perpendicularly to the axis and truncating a corner, and extending both ends of the truncated side in parallel until reaching one side of the conductor plate along the axis of symmetry; broadband antenna, characterized in that it comprises a feeding point pair respectively provided in the vicinity of the sandwich Element. The length and width of the conductor plate were 200 mm and the thickness was 0.1 mm, respectively. The length of one wedge in the axial direction was 84 mm, the length of the widened portion was 88 mm, and the truncated portion was cut off at the narrow portion. The length of the side portion is 12 mm, the length in the axial direction of the other wedge shape is 54 mm, the length of the wide portion is 88 mm, the length of the truncated side portion in the narrow portion is 10 mm, and both wedge shapes are formed. The width of the parallel portion connecting the widened portion is 88 mm, the length in the axial direction is 12 mm, the width of the communication hole connecting the wedge shape with the shorter length in the axial direction and one side of the conductor plate is 10 mm, and the length is 10 mm. 2. The broadband antenna element according to claim 1, wherein the width is 40 mm . A leg fixed vertically upward from a support table arranged on the floor, and a plate-like plate that is integrally formed with the leg with the plate surface oriented horizontally and supported by the leg. The supporting member comprises: a conductive conductor plate formed in a quadrilateral; and a substantially center line of the conductive plate , one center line of the quadrilateral having a symmetric axis, The distance between the edges facing each other across the axis gradually increased toward the center of the quadrilateral, and the two wedge shapes having different axial lengths and the widened portions of both wedge shapes faced each other. A cutout hole consisting of a side portion having a truncated corner perpendicular to the axis in a parallel portion connecting the portions in parallel, and a wedge-shaped narrow portion having a longer length in the axial direction; In the narrower wedge-shaped narrow part, the corner is cut off at right angles to the axis, The ends of the side portions, and a communication hole extending in parallel to reach the said conductor plate of one side along the axis of symmetry, antenna element and a pair of feed points respectively provided in the vicinity of sandwiching the communication hole a wideband indoor antenna, characterized in that the holding in position and shape.

Images