JPH1032418A - Flat antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flat antenna improving the appearance of a house and avoiding receiving a wind damage, etc., by providing an antenna for receiving a UHF band consisting of a conductive foil layer and a covering layer on the surface of a flat substrate. SOLUTION: An at least one antenna for receiving a UHF band 4 consisting of the conductive foil layer is arranged on one face of the flat substrate 2. Then the covering layer 6 is adhered so as to cover the antenna for receiving the UHF band 4. As the antenna for receiving the UHF band 4 consisting of the conductive foil layer is provided on the flat substrate 2 thus, the height size of this flat antenna 1 can remarkably be reduced. Consequently the antenna can be arranged on the rear side of a part of each of many roof tiles which are arrayed on the sheathing roof board of a roof, e.g. to avoid worsening the appearance of the house and receiving the influence of wind. In addition, receiving performance is not deteriorated de to a salt damage or acid rain.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat antenna formed on a flat substrate, and more particularly to a flat antenna receiving a UHF band radio wave.

[0002]

2. Description of the Related Art Conventionally, a Yagi antenna has been used as an antenna for receiving radio waves in the UHF band. The Yagi antenna has a reflector, a director, and a radiator mounted on an arm. In this Yagi antenna, the arm is mounted on a mast, and the mast is mounted on a roof using a roof horse or the like.

[0003]

However, in such a Yagi antenna, the shape is large, and the housing landscape is likely to deteriorate. Further, the Yagi antenna easily falls down when the wind is strong like a typhoon or the like, and is easily affected by so-called wind damage. In addition, when a Yagi antenna is used in a house near the seaside, salt adheres to the reflector, the waveguide, and the radiator, and is susceptible to so-called salt damage, which deteriorates reception performance. Further, the Yagi antenna may be squatted by acid rain, and the receiving performance may be degraded. When trying to remove the effects of wind damage, salt damage and acid rain, it is conceivable to arrange a Yagi antenna on the attic. In this case, a large gain reduction occurs in the Yagi antenna, which is not practical.

[0004] It is an object of the present invention to provide a flat antenna capable of improving a residential landscape. Another object of the present invention is to provide a flat antenna that is hardly affected by wind damage and salt damage.

[0005]

In order to solve the above-mentioned problems, the present invention is directed to a flat substrate, and at least one UHF formed by a conductive foil layer on one surface of the substrate. A band receiving antenna; and a coating layer formed on one surface of the substrate so as to cover the UHF band receiving antenna. Various antennas can be used as UHF band receiving antennas. For example, a fishbone type or a dipole type described later can be used.

According to a second aspect of the present invention, in the flat antenna of the first aspect, the UHF band receiving antenna is a fishbone type.

According to a third aspect of the present invention, in the flat antenna according to the second aspect, the fishbone-type antenna includes a pair of transmission lines provided at an interval and a pair of the transmission lines. It has a transmission path and dipole elements each extending substantially perpendicularly and in opposite directions. A plurality of dipole elements are provided at predetermined intervals along the transmission line. The distance between the tips of the dipole elements is set to about 0.5 to 1 wavelength of each reception center frequency signal. The frequencies of the reception center frequency signals are selected to be different from each other within the reception band of the flat antenna.

According to a fourth aspect of the present invention, in the flat antenna according to the first aspect, a plurality of the UHF band receiving antennas are arranged on one surface of the substrate at predetermined intervals. .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Flat antenna 1 of the present embodiment
1 has a substrate, for example, a dielectric substrate 2 formed of a printed board, as shown in FIG. This dielectric substrate 2
Is formed in, for example, a pentagon. This shape can be any shape.

The flat antenna 1 is arranged so that the longitudinal edge of the dielectric substrate 2 is substantially perpendicular to the receiving direction (the direction of arrival of the received radio wave). On one surface of the dielectric substrate 2, two UHF band receiving antennas 4 are provided.
Are arranged along the longitudinal edge of These two UHF
The band receiving antenna 4 is formed by etching a conductive foil, for example, a metal foil, which is thinner than the thickness of the dielectric substrate 2 attached on the dielectric substrate 2. These two UHF band receiving antennas 4 are, for example, fishbone type.

As shown in FIG. 1B, a coating layer 6 is applied on the dielectric substrate 2 so as to cover these UHF band receiving antennas 4. The coating layer 6 is made of a layer of a material that does not hinder the arrival of radio waves to the UHF band receiving antennas 4, 4, for example, a resin film of polyester or the like. The coating layer 6 is in contact with the entire surface of the UHF band receiving antennas 4 and 4, and is also in contact with the portion of the dielectric substrate 2 where the UHF band receiving antennas 4 and 4 are not provided. That is, the receiving antennas 4 and 4 in the UHF band are closed. In FIG. 1B, the thicknesses of the dielectric substrate 2, the receiving antenna 4 in the UHF band, and the coating layer 6 are exaggerated.

Since the UHF band receiving antennas 4 and 4 are provided on the dielectric substrate 2 as described above, the height of the flat antenna 1 is very small. For example, as shown in FIG. 2, the flat antenna 1 can be arranged on the back surface of a part of each of the tiles 10 arranged on a roof base plate 8. Therefore, the housing landscape does not deteriorate,
It is hardly affected by wind damage. In addition, since the receiving antennas 4 and 4 in the UHF band are covered with the coating layer 6, the receiving performance does not deteriorate due to salt damage or acid rain. The roof tiles 10 are made of a material that transmits radio waves.

The UHF band receiving antennas 4 and 4 are 470M
It is for receiving a radio wave of from Hz to 770 MHz. Since they have the same shape, only one of them will be described. UHF band receiving antenna 4
It has a pair of transmission lines 12,12. These transmission lines 12 and 12 are provided on the dielectric substrate 2 substantially at right angles to the longitudinal edges of the dielectric substrate 2, that is, substantially parallel to the arrival direction (front direction) of radio waves. These transmission lines 12, 12 are:
They are arranged at predetermined intervals along the longitudinal edge of the dielectric substrate 2.

The four dipole elements 14, 16, 1 are arranged at predetermined intervals along the length of the transmission line 12.
8 and 20 are provided. The dipole element 14
The pair of transmission paths 12 extend from the position farthest from the longitudinal edge of the dielectric substrate 2, that is, a position on the far side, on both sides in parallel with the longitudinal edge of the dielectric substrate 2. The distance between the tips of the dipole element 14 is from the reception frequency band 470 MHz of the reception antenna 4 in the UHF band to 770 MHz
0.5 of wavelength λ1 of frequency 500 MHz included in z
4 having a length of about 1 to about 0.72λ1, for example.
It is set to 30 mm.

The dipole element 16 is a dipole element 1
4, transmission lines 12 and 1 closer to the longitudinal edge of the dielectric substrate 2.
2 extend on both sides in parallel with the longitudinal edge of the dielectric substrate 2. The distance between the tips of the dipole elements 16 is 0.5 to 1 times the wavelength λ2 of 660 MHz included in the reception frequency band, for example, 0.95λ.
2, which is 410 mm.

The dipole element 18 is a dipole element 1
6, transmission lines 12 and 1 closer to the longitudinal edge of the dielectric substrate 2.
2 extend on both sides in parallel with the longitudinal edge of the dielectric substrate 2. The distance between the tips of the dipole elements 18 is 0.5 to 1 times the wavelength λ3 of 700 MHz included in the reception frequency band, for example, 0.93λ.
3 is set to 390 mm.

The dipole element 20 is a dipole element 1
8, transmission lines 12 and 1 closer to the longitudinal edge of the dielectric substrate 2.
2 extend on both sides in parallel with the longitudinal edge of the dielectric substrate 2. The distance between the tips of the dipole element 20 is 0.5 to 1 times the wavelength λ4 of 770 MHz included in the reception frequency band, for example, 0.9λ4
Is set to 370 mm.

In a normal fishbone antenna,
Each dipole element has the same length. However, in order to satisfactorily receive radio waves from 470 MHz to 770 MHz, which are relatively wide bands, the flat antenna 1 has different distant frequencies 500 MHz, 660 MHz, 700 MHz and 7 MHz within this reception band.
The dipole elements 14 and 1 are resonated at 70 MHz.
6, 18, and 20 lengths have been selected. Further, the gain of these dipole elements 14, 16, 18, 20 does not extremely decrease at a frequency close to their resonance frequency. Therefore, the dipole elements 14, 1
By selecting the lengths of 6, 18, and 20, radio waves in the UHF band of a relatively wide band can be satisfactorily received.

Each dipole element 14, 16, 1
The distance between the centers 8 and 20 along the transmission lines 12 and 12 is, for example, 45 mm from the center of each dipole element. This corresponds to about 0.075 times the wavelength λ1 of the reception band of the UHF band, about 0.1 times of λ2, about 0.11 times of λ3 and λ4, and generally about 0.1 times. Further, the distance between the centers of the transmission lines 12, 12 is 82m.
m, ie, about 0.14 times of λ1, about 0.18 times of λ2,
It is about 0.2 times λ3 and λ4.

Since the UHF band receiving antennas 4 and 4 are of a fishbone type, they function as a kind of endfire array antenna, and are arranged on the same plane as the UHF band receiving antennas 4 and 4 as shown in FIG. The maximum gain can be obtained in the front direction, and the antenna has a good F / B ratio. Also, since the fishbone type is used, the directivity in the direction perpendicular to the UHF band receiving antennas 4 and 4, that is, in the direction perpendicular to the dielectric substrate 2, is broad as shown in FIG. FIG. 4 shows the directivity of the vertical plane when the angle θ of the roof is 30 degrees in the roof as shown in FIG. Since the antenna has such horizontal plane directivity and vertical plane directivity, even if the flat antenna 1 is arranged on the roof as shown in FIG. 2, a decrease in the gain in the radio wave arrival direction is small.

FIG. 5 shows gain versus frequency characteristics and VSWR versus frequency characteristics of the flat antenna 1. According to the flat antenna 1, a gain of at least about 3 dB is obtained in the reception band, and a gain of about 7 dB is obtained at the maximum. Further, according to the flat antenna 1, a VSWR of at least 3.5 and a VSWR of at most about 1.4 are obtained in the reception band.

In the innermost part of the transmission lines 12, 12,
Each of the power supply units 22 is formed. These power supply units 2
2 are formed substantially U-shaped, and one of their legs is
They are arranged in parallel with the dipole elements 14, 16, 18, 20 and are connected to the transmission lines 12, 12. The other leg is connected to the coaxial plug by electrostatic coupling. By forming the power supply unit 22 in a U-shape in this way, an inductance component is provided to prevent impedance mismatch. Further, the distance d between the U-shaped power supply units is 10 m.
m, that is, about 0.01 times as long as λ1 to λ4, impedance matching is performed. A power supply unit 22 is connected from the coaxial plug to a television receiver via a coaxial cable. Of course, since this power supply portion is also covered with the coating layer 6, it does not enter the UHF band receiving antenna 4 from the vicinity of the power supply portion 22.

In this flat antenna 1, two UHF
The band receiving antenna 4 is provided on the dielectric substrate 2. This is because the combined directivity of the two receiving antennas 4 and 4 can be varied by feeding the phase difference to the two UHF receiving antennas 4 and 4. Therefore, FIG.
Use a circuit as shown in

In the circuit shown in FIG. 6, the reception output of one UHF band reception antenna 4 is supplied to the synthesizer 24 as it is. The reception output of the other UHF band reception antenna 4 is supplied to the combiner 24 after the phase adjustment is performed by the phase shifter 26. The two signals are combined by the combiner 24. From the UHF band receiving antennas 4 and 4 to the synthesizer 26
Assuming that signals are supplied by feeder lines L1 and L2 of the same length up to and the phase adjustment is not performed by the phase shifter 26, when both signals are supplied to the combiner 24, the directivity is maximum in the front direction. Becomes

Adjusting the phase by the phase shifter 26 is equivalent to changing the length of the feed line. Therefore, for example, the antenna 4,
When the combined directivity of the antenna 4 is directed, assuming that the distance between the antennas 4 and 4 (the distance along the longitudinal edge of the dielectric substrate 2) is d, the phase shifter 26 controls the antenna 4 on the feed line L2 side.
Are delayed by dsin θ, the in-phase received signals are supplied to the combiners 24, and have directivity in the direction of θ. Therefore, for example, when the flat antenna 1 is installed as shown in FIG. 2, the radio wave does not travel straight from the right side of FIG.
The radio wave can be satisfactorily received by adjusting the phase shifter 26 even when heading toward the flat antenna 1 from the back side or the near side of the paper surface of FIG.

In the above-described embodiment, the fishbone type UHF band receiving antenna 4 is provided on the dielectric substrate 2, but other antennas, such as dipole antennas, may be used as long as they can be constituted by conductive foil. it can. Further, in the above-described embodiment, two receiving antennas 4 for the UHF band are provided on the dielectric substrate 2, but only one receiving antenna 4 may be provided, or three or more receiving antennas 4 for the UHF band may be provided. Can also.

For example, when four receiving antennas 4a to 4d are used, the two receiving antennas 4a to 4d can be arranged in two rows each on one dielectric substrate 2, as shown in FIG. As shown in FIG. 8, four receiving antennas 4a to 4d can be arranged on the dielectric substrate 2 in one line. Although these receiving antennas 4a to 4d are simplified in FIGS. 8 and 9, they are the same as the receiving antenna 4 shown in FIG. Of course, two flat antennas provided with two receiving antennas on one dielectric substrate as shown in FIG. 1 can also be used. In any case, the phase difference feeding can be performed as shown in FIG. 9 or FIG.

In FIG. 9, the reception outputs of the receiving antennas 4a and 4c are supplied as they are to the combiners 24a and 24c.
The reception outputs of the receiving antennas 4b and 4d are output from the phase shifters 26a,
After the phase adjustment is performed by 26b, the combiner 24a,
24b. A reception output of the reception antenna 4a;
Receiving antenna 4b phase-adjusted by phase shifter 26a
Are combined by the combiner 24a. Similarly, the combiner 24b combines the receive output of the receive antenna 4c and the output of the receive antenna 4d whose phase has been adjusted by the phase shifter 26b. The output of the synthesizer 24a is
It is supplied to the synthesizer 24c as it is. After the output of the combiner 24b is adjusted in phase by the phase shifter 26c, it is supplied to the combiner 24c and combined with the output of the combiner 24a.

In FIG. 10, the output of the receiving antenna 4a is supplied to the combiner 24d as it is. The reception outputs of the receiving antennas 4b, 4c, and 4d are phase shifters 26d to
The phases are adjusted by f and supplied to the synthesizer 24d. Each signal supplied to the combiner 24d is combined by the combiner 24d.

[0030]

As described above, according to the first aspect of the present invention, at least one UHF band receiving antenna is formed by a conductive foil layer on one surface of a flat substrate and a substrate. The height of the UHF band receiving antenna is very small. Therefore, even if the antenna according to the first aspect is mounted on the roof of a house or the like, the landscape of the house is not impaired, and even if the wind is strong, the antenna is not damaged and is hardly affected by wind damage. In addition, since the coating layer is formed on one surface of the substrate so as to cover the UHF band receiving antenna, the antenna according to claim 1 is installed in a house near the coast, for example. Not affected. Further, the antenna according to the first aspect is not exposed to acid rain and does not corrode.

According to the second aspect of the invention, since the UHF band receiving antenna is of a fishbone type, the F / B ratio of the horizontal plane directivity is good, the vertical plane directivity is broad, and the inclination is large. When used for roofs, etc.
The radio waves in the UHF band can be received well.

According to the third aspect of the present invention, the distance between the tips of the plurality of dipole elements of the fishbone type antenna is set to about 0.5 to 1 wavelength of each reception center signal, Since the frequencies of the signals are different from each other within the reception band of the flat antenna, the radio waves can be satisfactorily received in the entire UHF band, which is a relatively wide band.

According to the fourth aspect of the present invention, a plurality of UH
Since the F-band receiving antennas are arranged on one surface of the substrate at a predetermined interval, the plurality of UHF-band receiving antennas are fed with a phase difference to combine the plurality of UHF-band receiving antennas. The directivity can be changed. Therefore, for example, even when the front direction of the flat antenna cannot be turned to the arrival direction of the radio wave due to the orientation of the roof of the house, the radio wave can be satisfactorily received.

[Brief description of the drawings]

FIG. 1A is a plan view of a flat antenna according to an embodiment of the present invention, and FIG. 1B is an end view taken along line AA of FIG.

FIG. 2 is a diagram showing an arrangement state of the flat antenna.

FIG. 3 is a diagram showing the horizontal directivity of the flat antenna.

FIG. 4 is a diagram showing vertical plane directivity of the flat antenna.

FIG. 5 is a diagram illustrating gain vs. frequency characteristics and VS of the planar antenna.
It is a figure showing WR vs. frequency characteristics.

FIG. 6 is a circuit diagram of a circuit used for phase difference feeding in the flat antenna.

FIG. 7 is a plan view of a flat antenna according to another embodiment of the present invention.

FIG. 8 is a plan view of a planar antenna according to another embodiment of the present invention.

9 is a circuit diagram of an example of a circuit used for phase difference feeding in the flat antenna of FIG. 7 or FIG. 8;

FIG. 10 is a circuit diagram of another example of a circuit used for phase difference feeding in the flat antenna of FIG. 7 or FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 flat antenna 2 dielectric substrate 4 4 a to 4 d UHF band receiving antenna 6 coating layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01Q 21/06 H01Q 21/06 21/08 21/08

Claims (4)

[Claims] 1. A flat substrate, at least one UHF band receiving antenna formed by a conductive foil layer on one surface of the substrate, and the substrate so as to cover the UHF band receiving antenna in contact with the UHF band receiving antenna. And a covering layer formed on one surface of the flat antenna. 2. The flat antenna according to claim 1, wherein said UHF band receiving antenna is of a fishbone type. 3. The flat antenna according to claim 2, wherein said fishbone type antenna is provided with a pair of transmission lines provided at an interval and each of said pair of transmission lines is substantially perpendicular to said transmission lines. Dipole elements extending in opposite directions to each other, and a plurality of dipole elements are provided at predetermined intervals along the transmission line,
The distance between the tips of the dipole elements is set to about 0.5 to 1 wavelength of each reception center frequency signal, and the frequency of each reception center frequency signal is different in the reception band of the flat antenna. Flat antenna that is frequency. 4. The flat antenna according to claim 1, wherein a plurality of the UHF band receiving antennas are arranged on one surface of the substrate at predetermined intervals.