JP3754258B2 - Antenna device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a small, lightweight, wide-band vertically polarized horizontal plane omnidirectional antenna device used for, for example, in-vehicle use and indoor ceiling mounting in mobile communication.
[0002]
[Prior art]
Conventionally, vertically polarized horizontal plane omnidirectional antennas for small and light in-vehicle and indoor ceiling mounting in mobile communication use, for example, monopole type, inverted L type, inverted F type, etc., single frequency band Used in.
[0003]
FIG. 7 shows a configuration of a conventional monopole antenna. In FIG. 7, reference numeral 1 denotes a ground plate. A coaxial plug 2 is attached to the ground plate 1 from the lower side in the figure, and its central conductor 3 is insulated from the ground plate 1 and extends upward by about 1 / 4λ. At this time, the detailed dimensions of the center conductor 3 depend on the impedance characteristics and are determined based on the impedance characteristics.
[0004]
FIG. 8 shows a configuration of an inverted L-shaped antenna. The central conductor 3 of the coaxial plug 2 attached to the ground plate 1 is extended upward by about ¼λ, and 90 ° horizontally from the central portion. It is bent. At this time, the detailed dimensions of the center conductor 3 are determined depending on the impedance characteristics.
[0005]
FIG. 9 shows the configuration of an inverted F-shaped antenna. The center conductor 3 of the coaxial connector 2 attached to the ground plate 1 is extended upward, and a predetermined portion of the inverted L-shaped element 4 is formed at the tip thereof. Connect position electrically. In the inverted L-shaped element 4, the lower end of the vertical portion parallel to the center conductor 3 is electrically connected to the ground plate 1, and the horizontal portion is connected to the tip of the center conductor 3. At this time, the positional relationship and detailed dimensions of the central conductor 3 and the inverted L-shaped element 4 are determined depending on the impedance characteristics.
[0006]
According to the above-described prior art, good communication can be performed at a single frequency, and a small and lightweight antenna device can be realized.
[0007]
[Problems to be solved by the invention]
However, in any of the above conventional antenna devices, the impedance characteristic is a narrow band in any case, for example, when the standing wave ratio is 2.0 or less, the ratio band is only a few percent to a few dozen percent, and multi-frequency band sharing is difficult. is there.
[0008]
In recent years, many frequency bands are mixed. For example, in mobile phones, 800 MHz band, 1500 MHz band, and next generation 2000 MHz band are mixed, and it is necessary to install antennas corresponding to each frequency band. .
However, there are cases where it is difficult to install several types of antennas due to limitations of installation space, aesthetic problems, and the like. In addition, there is a problem that only a limited frequency band can be used when many types of antennas cannot be installed due to the above-described problem of installation location restrictions.
[0009]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an antenna device having a wideband characteristic that can be shared by multiple frequency bands.
[0010]
[Means for Solving the Problems]
An antenna device according to a first aspect of the present invention includes a ground plate, a coaxial plug that is attached to the lower side of the ground plate, and a center conductor is provided so as to protrude from the upper side surface of the ground plate, and an upper central portion of the ground plate. A printed circuit board that is perpendicular to the printed circuit board, a semicircular copper foil formed on one surface of the printed circuit board so that the top is located on the ground plate side, and the top of the semicircular copper foil and the coaxial contact Means for electrically connecting the central conductor of the stopper, a strip-shaped copper foil formed on the other surface of the printed circuit board so as to be positioned on the ground plate side, provided on both sides of the printed circuit board, and having an upper end A metal plate electrically connected to the semicircular copper foil from the upper central portion of the printed circuit board and having a lower end electrically connected to the ground plate ; characterized by being arranged at an inclination angle
[0011]
According to a second aspect of the invention, in the antenna device according to the first aspect of the invention, a component formed on the upper side of the ground plate is covered with an insulating cover.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1A and 1B show a configuration of a wideband vertical polarization horizontal plane omnidirectional antenna device according to an embodiment of the present invention. FIG. 1A is a front view, FIG. 1B is a side view, and FIG. , (D) is a top view. Moreover, FIG. 2 is for demonstrating the setting dimension of the semicircle copper foil and strip | belt-shaped copper foil vapor-deposited on the printed circuit board in the embodiment, (a) is a front view, (b) is a rear view. is there.
[0013]
In FIG. 1, reference numeral 11 denotes a ground plate having a diameter of, for example, 0.5λ0 (λ0: center wavelength) or more. A coaxial plug 12 is attached to the ground plate 11 at the lower center, and a central conductor 13 is projected above the ground plate 11. In this case, the center conductor 13 is held in an insulated state from the ground plate 11. A rectangular printed board 14 is vertically arranged at the upper center of the ground plate 11 and held by metal plates 15a and 15b.
[0014]
As shown in FIG. 1A, a semicircular copper foil 14a is vapor-deposited on the printed circuit board 14 on one surface facing the central conductor 13 of the coaxial plug 12, as shown in FIG. Thus, the strip-shaped copper foil 14b is deposited on the other surface in the vicinity of the ground plate 11. The semicircular copper foil 14a is appropriately insulated by an insulator so as to be insulated from the ground plate 11, and the strip-shaped copper foil 14b is disposed so as to be in an insulated state from other metals.
[0015]
As shown in FIG. 2A, the semicircular copper foil 14a of the printed circuit board 14 has a maximum width w1 of 0.3λ0 to 0.4λ0 and a height h1 of 0.15λ0 to 0.2λ0. The central conductor 13 of the coaxial connector 12 is electrically connected to the vicinity of the top of the arc (the ground plate 11 side). Further, as shown in FIG. 2B, the strip-shaped copper foil 14b is set in a range where the width w2 is 0.3λ0 to 0.4λ0 and the height h2 is 0.05λ0 to 0.1λ0.
[0016]
And as shown in FIG.1 (b), the upper end of the metal plates 15a and 15b is fixed to the both sides of the upper end of the printed circuit board 14 with the screw 16, and between the semicircular copper foil 14a and the metal plates 15a and 15b is electrically connected. Connected to. In this case, the metal plates 15 a and 15 b are arranged so that an angle θ formed with the printed circuit board 14 is 30 ° to 45 °, and a lower portion thereof is electrically connected to the ground plate 11. The width w3 of the metal plates 15a and 15b is set in the range of 0.05λ0 to 0.2λ0. Of course, the electrical connection between the semicircular copper foil 14a of the printed circuit board 14 and the metal plates 15a and 15b may be performed by a method other than screwing.
The above detailed dimensions are determined depending on the desired frequency band and impedance characteristics.
[0017]
Further, an insulating cover 17 for protecting the printed circuit board 14 and antenna elements such as the metal plates 15a and 15b is mounted on the upper side of the ground plate 11 as shown in FIG. FIG. 3A is a front view of the antenna device showing a state where the insulating cover 17 is attached, and FIG. 3B is a top view.
[0018]
As described above, the semicircular copper foil 14a provided on the printed circuit board 14 is electrically connected to one end of the metal plates 15a and 15b, and the other end of the metal plates 15a and 15b is connected to the ground plate 11. Thus, an antenna element shape in which the change in impedance in the frequency characteristic becomes gradual is formed, and further, the impedance is corrected by the strip-shaped copper foil 14b to widen the band, and the metal plates 15a and 15b are grounded from the semicircular copper foil 14a. By using a folded structure that is electrically connected to the plate 11, the posture can be lowered.
[0019]
Further, by covering the antenna element portion with the insulating cover 17, it is possible to obtain a shape that is aesthetically superior.
Furthermore, the antenna device according to the present invention can be realized with a simple structure by using the printed circuit board 14 and the metal plates 15a and 15b which are press parts, and the cost can be reduced.
[0020]
FIG. 4 is a diagram showing the standing wave ratio characteristics when the center frequency f0 is 1.8 GHz in the antenna device shown in the above embodiment. As can be seen from this characteristic diagram, a broadband characteristic of about 60% is obtained in a specific band at a standing wave ratio of 2.0 or less.
[0021]
FIG. 5 is a diagram showing the vertical polarization horizontal plane directivity of the antenna device, and FIG. 6 is a diagram showing the vertical polarization vertical plane directivity. The antenna device operates well as a vertical polarization horizontal plane omnidirectional antenna.
[0022]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to realize a small, lightweight, wide-band, vertically polarized horizontal plane omnidirectional antenna device with an aesthetically pleasing shape and at low cost. In addition, the number of antennas can be reduced without reducing the usable frequency band, and installation is possible even in places where there are restrictions due to the convenience of installation space, aesthetic problems, and the like. Furthermore, since the number of antennas can be reduced, the work burden during construction can be reduced, and high economic efficiency can be obtained.
[Brief description of the drawings]
1A and 1B show an antenna device according to an embodiment of the present invention, in which FIG. 1A is a front view showing an antenna element portion with an insulating cover removed, FIG. 1B is a side view, FIG. ) Is a top view.
FIG. 2 is a view for explaining set dimensions of a semicircular copper foil and a strip-shaped copper foil deposited on a printed circuit board in the embodiment.
3A and 3B show a state in which an insulating cover of the antenna device according to the embodiment is mounted, in which FIG. 3A is a front view, and FIG. 3B is a top view.
FIG. 4 is a diagram showing a standing wave ratio characteristic in the embodiment.
FIG. 5 is a view showing vertical polarization horizontal plane directivity in the same embodiment;
FIG. 6 is a view showing vertical polarization vertical plane directivity in the same embodiment;
FIG. 7 is a diagram showing a configuration of a conventional monopole antenna.
FIG. 8 is a diagram showing a configuration of a conventional inverted L antenna.
FIG. 9 is a diagram showing a configuration of a conventional inverted F antenna.
[Explanation of symbols]
11 Ground plate 12 Coaxial plug 13 Central conductor 14 Printed circuit board 14a Semi-circular copper foil 14b Strip copper foil 15a, 15b Metal plate 16 Screw 17 Insulation cover

Claims (2)

A grounding plate, a coaxial plug mounted on the lower side of the grounding plate and having a central conductor protruding from the upper side surface of the grounding plate, a printed circuit board provided perpendicular to the upper central portion of the grounding plate, A semicircular copper foil formed so that the top portion is located on one side of the printed board on the ground plate side, and the top portion of the semicircular copper foil and the central conductor of the coaxial plug are electrically connected. And a strip-shaped copper foil formed on the other surface of the printed circuit board so as to be positioned on the ground plate side, provided on both sides of the printed circuit board, and the upper end is semicircular from the upper central part of the printed circuit board A metal plate electrically connected to the copper foil and having a lower end electrically connected to the ground plate, wherein the metal plate is disposed at a predetermined inclination angle with respect to the printed board. Antenna device. A grounding plate, a coaxial plug mounted on the lower side of the grounding plate and having a central conductor protruding from the upper side surface of the grounding plate, a printed circuit board provided perpendicular to the upper central portion of the grounding plate, A semicircular copper foil formed so that the top portion is located on one side of the printed board on the ground plate side, and the top portion of the semicircular copper foil and the central conductor of the coaxial plug are electrically connected. And a strip-shaped copper foil formed on the other surface of the printed circuit board so as to be positioned on the ground plate side, provided on both sides of the printed circuit board, and the upper end is semicircular from the upper central part of the printed circuit board A metal plate electrically connected to the copper foil and having a lower end electrically connected to the ground plate, and an insulating cover covering the components formed on the upper side of the ground plate,
The antenna apparatus according to claim 1, wherein the metal plate is arranged at a predetermined inclination angle with respect to the printed circuit board .

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