WO2003041222A1

WO2003041222A1 - Antenna

Info

Publication number: WO2003041222A1
Application number: PCT/JP2002/011706
Authority: WO
Inventors: Masayoshi Aikawa; Eisuke Nishiyama; Osamu Nakano; Koichi Inenaga; Shingo Mukae; Hirofumi Yamaguchi; Kotaro Koda; Kunihiko Sakemi; Toru Uenosono
Original assignee: Nippon Tungsten Co., Ltd.; Nishimu Electronics Industries Co., Ltd.
Priority date: 2001-11-09
Filing date: 2002-11-08
Publication date: 2003-05-15
Also published as: TW200300619A; JPWO2003041222A1

Abstract

A high-gain small-sized antenna for communication. The antenna has a multilayer structure of a ground conductive sheet, a feeding element of a metal sheet disposed on the ground conductive sheet, a first passive element of a metal sheet spaced from the feeding element by 0.01 to 0.2 wavelengths and a second passive element of a metal sheet spaced from the first passive element spaced from the first passive element by 0.2 to 0.8 wavelengths. Therefore the band of the antenna is widened, the width of the beam is narrowed and the directivity is enhanced. A dielectric body of high dielectric constant is disposed between the feeding element and the passive elements over the feeding element of the multilayer structure to shorten the dimension in the height direction by the shorted wavelength in the dielectric body.

Description

Description Antenna Technical field

The present invention relates to an antenna mainly used in the communication field, and particularly to a small antenna suitable for use in a communication field having a high frequency. Background art

Although the antenna of the present invention can be widely used in the field of communication, it is particularly suitable as a microwave antenna. Conventional antennas in this field include a microstrip antenna or a patch antenna (plane antenna). This planar antenna usually comprises a ground conductor plate, a dielectric plate superimposed on the ground conductor plate, and a strip or patch-shaped thin metal feed element superposed on the dielectric plate. The radiating element and the feed line can be easily manufactured on the printed circuit board by the etching process, and it is used as a thin and lightweight antenna for small communication devices such as mobile phones.

Fig. 20 and Fig. 21 show the directivity of this conventional planar antenna in the radial horizontal plane. The beam width at 2.45 GHz is 60 degrees.

When a plurality of radiating elements are arranged on a printed circuit board to increase the gain with this antenna and individually feed power, there is a problem in that the area increases and the feed loss increases. Even at high frequencies, the planar antenna becomes large at frequencies lower than the centimeter wave, and the array configuration described above for high gain increases the appearance, for example, when installed in a house, and as a result, the structure Problems also arise in strength.

An object of the present invention is to provide a communication antenna having a high gain and a small size, and a communication antenna having a wide band and a narrow directivity. Disclosure of the invention

An antenna according to the present invention that achieves the above object has a ground conductor plate, a thin metal plate-shaped feed element disposed on the ground conductor plate, and a thin metal plate disposed about 0.01 to 0.2 wavelength away from the feed element. An antenna provided with a layered structure including the first parasitic element described above and a second metal-plate-shaped parasitic element arranged at a distance of 0.2 to 0.8 wavelength, preferably 0.4 to 0.6 wavelength from the feeding element.

Two resonance states with slightly different center frequencies by slightly differentiating the dimensions of the feeder element and the dimensions of the first metal-plate-shaped parasitic element placed at a distance of about 0.01 to 0.2 wavelength from this feeder element Is generated, and the resonance band is expanded as a total resonance, and a wide-band antenna is obtained. Further, the radiation beam is narrowed down by the second parasitic element arranged at a distance of 0.2 to 0.8 wavelength, preferably 0.4 to 0.6 wavelength from the feed element, and the directivity characteristic and the gain are improved. Because it is a stratified structure, it does not take up a large area.

The layered structure may include a third metal-plate-shaped parasitic element spaced from the second parasitic element by 0.2 to 0.8 wavelength, preferably 0.4 to 0.6 wavelength. The directivity can be further improved by the third parasitic element.

The layered structure includes a metal-plate-shaped parasitic element arranged at a distance of 0.2 to 0.8 wavelength, preferably 0.4 to 0.6 wavelength from the third parasitic element. It is determined by the convergence of the beam stop effect determined by the size of the plate. Although the beam width becomes narrower as the number of parasitic elements after the fourth increases, the degree of the narrowing effect becomes nonlinearly smaller, and there is no point in increasing the number of parasitic elements further. As the ground conductor plate is larger, the number of parasitic elements can be increased. In reality, the fourth and subsequent parasitic elements are determined according to the target narrowing effect.

The shape of the feeding element and the parasitic element may be a strip, a circle or a square. By providing a metal case with an open front to accommodate the laminated structure, it is possible to suppress electromagnetic radiation to the side, and to increase the gain by reflecting the radiation energy in the forward radiation direction.

A radio wave absorber is placed on the side of the layered structure to absorb electromagnetic radiation to the side. It can also be done.

In addition, the antenna of the present invention, which mainly has the above object, particularly, a wide band and a small size, includes a ground conductor plate, a metal plate-shaped feed element disposed on the ground conductor plate, It has a stratified structure consisting of a dielectric plate spaced apart or in close contact with the feeder element, and a metal plate-shaped parasitic element placed apart from or closer to the dielectric plate. Antenna.

The presence of a dielectric plate having a dielectric constant higher than that of air makes the wavelength of electromagnetic waves shorter than that of air, which can reduce the height of the stratified structure and contribute to miniaturization. In addition, a plurality of resonance states of the resonance of the feed element and the resonance between the feed element and the dielectric plate occur, and the resonance band is expanded as a total resonance, thereby providing a wide-band antenna. Also in this case, the shape of the feeding element and the parasitic element may be a strip, a circle, or a square. The stratified structure can be housed in a metal case with an open front to suppress electromagnetic radiation to the side and reflect energy in the forward radiation direction to increase the gain. Further, an electromagnetic wave absorber may be arranged on the side surface of the layered structure.

Further, in the antenna of the present invention, a support rod made of a conductor or an insulator material is attached to a central axis of a laminated structure including a ground conductor plate, a metal sheet-shaped feeding element, and a metal sheet-shaped parasitic element, Alternatively, a support rod made of an insulating material is attached to a given position other than the central axis of the laminated structure, and the laminated structure is integrally fixed. Further, a low dielectric constant spacer may be arranged between the feeding element and the parasitic element of the layered structure to integrate the layered structure. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of the antenna according to the first embodiment of the present invention.

FIG. 2 is a reflection characteristic diagram of an antenna having only a feed element.

FIG. 3 is a reflection diagram of a feed element and a parasitic element antenna.

FIG. 4 is a directional characteristic diagram of the antenna according to the first embodiment of the present invention. FIG. 5 is a developed view of the directional characteristics of the antenna according to the first embodiment of the present invention. FIG. 6 is a perspective view of the antenna according to the second embodiment of the present invention. FIG. 7 is a directional characteristic diagram of the antenna according to the second embodiment of the present invention.

FIG. 8 is a developed view of the directional characteristics of the antenna according to the second embodiment of the present invention. FIGS. 9A and 9B are side sectional views showing a state in which the antenna according to the second embodiment of the present invention is housed in a metal case, and FIGS. 9B and 9C are perspective views showing other examples of the metal case. (D) is a diagram showing a change in the angle of the metal plate and a change in the directivity characteristics.

FIG. 10 is a directional characteristic diagram of the antenna of FIG. 9 (a).

FIG. 11 is a developed view of the directional characteristics of the antenna of FIG. 9 (a).

FIG. 12 is a perspective view of the antenna according to the third embodiment of the present invention.

FIG. 13 is a directional characteristic diagram of the antenna according to the third embodiment of the present invention. FIG. 14 is a developed view of the directional characteristics of the antenna according to the third embodiment of the present invention.

FIG. 15 is a directional characteristic diagram of the antenna according to the third embodiment of the present invention housed in a metal case.

FIG. 16 is a developed view of the directivity characteristics of the antenna according to the third embodiment of the present invention housed in a metal case.

FIG. 17 is a side sectional view showing the antenna according to the fourth embodiment of the present invention. FIG. 18 is a side sectional view showing the antenna according to the fifth embodiment of the present invention. FIG. 19 is a side sectional view showing the antenna according to the sixth embodiment of the present invention. FIG. 20 is a directional characteristic diagram of a conventional patch antenna.

FIG. 21 is a developed view of the directional characteristics of a conventional patch antenna. BEST MODE FOR CARRYING OUT THE INVENTION

Refer to FIG. The laminated thin plate antenna includes a ground conductor plate 1, a thin metal plate feed element 2 disposed on the ground conductor plate, and a first thin metal plate parasitic antenna disposed 0.1 wavelength away from the feed element 2. A layered structure including an element 3 and a second metal-free parasitic element 4 in the form of a thin metal plate arranged at a distance of 0.5 wavelength from the feed element 2 is provided.

By slightly differing the dimensions of the feed element 2 and the dimensions of the first parasitic element 3 that is placed 0.1 wavelength apart, two resonance states slightly separated in resonance frequency occur Then, the resonance band is expanded as a total resonance. Experiments have confirmed the band extension effect when this space is about 0.01 to 0.2 wavelength long, and also contributes to a reduction in the height of the stratified structure. This is evident by comparing FIG. 2 showing the reflection characteristics of only the feed element 2 with FIG. 3 showing the reflection characteristics when the first parasitic element 3 is loaded.

Further, the radiation beam is narrowed down narrowly by the second parasitic element arranged at a distance of 0.5 wavelength from the feed element 2, and the directivity characteristics and the gain are improved. As shown in Fig. 4 and Fig. 5, the beam width in the radiation horizontal plane at 2.45GHz and the beam width in the vertical plane are both 44 degrees, and the beam width in the radiation horizontal plane of a normal planar antenna is 60 degrees. Significant improvement over degree. It has been experimentally confirmed that the interval of about 0.5 wavelength is most effective in converging the beam width. FIG. 6 shows an embodiment in which the layered structure includes a thin metal plate-shaped third parasitic element 5 arranged at a distance of 0.5 wavelength from the second parasitic element 4. The directional characteristics are further improved by the third parasitic element 5. As shown in Fig. 7 and Fig. 8, the beam width in both the horizontal plane and the vertical plane at 2.45GHz is 37.5 degrees, which is further improved compared to the antenna's 44 degrees in Fig. 1.

Metal thin plate-shaped fourth and subsequent parasitic elements may be placed 0.5 wavelength away from the third parasitic element to further narrow the beam, but the size of the ground conductor is naturally limited. Therefore, no appreciable improvement in its directional characteristics is observed.

Also in this case, the shape of the feeding element and the parasitic element is square, but may be a strip or a circle.

See FIG. 9 (a). The laminated structure is housed in a metal case 6 that is open front. The metal case 6 has a structure including the ground conductor plate 1 on the bottom surface and the metal plate 6a on the side surface. Reference numeral 7 denotes a power supply connector. This metal case suppresses electromagnetic wave radiation to the side and reflects radiant energy in the forward radiation direction to increase the gain. As shown in Figs. 10 and 11, the beam width in the horizontal plane at 2.45 GHz is 35 degrees in the horizontal plane, and the beam width in the vertical plane is 43 degrees. Radiation to the side and rear is significantly suppressed, In addition, the beam width in the horizontal plane of 35 degrees is smaller than that of the antenna of Fig. 6 at 37.5 degrees, and the gain is accordingly improved.

The metal case that houses the layered structure will be described. See Fig. 9 (a). The shape of the ground conductor plate 1 on the bottom of the layered structure may be various shapes such as a circle, a polygon, and the like, in addition to a rectangle. In addition, the shape of the ground conductor plate can be flat or curved. The metal plate 6a has an inclination angle 0 (0 is in the range of 0 ° <0 ≤ 90 °) from the extension direction of the ground conductor plate 1 on the bottom of the laminated structure, and its shape may be flat or curved. it can. By adjusting the height of the metal plate 6a and the tilt angle 0, desired directional characteristics can be obtained. In addition, by connecting the ground conductor plate 1 and the metal plate 6a on the bottom of the laminated structure by various joining methods such as hinge structure, bellows structure, and ball joint structure, the inclination angle Θ can be changed and the directivity characteristics can be easily changed. can do. Furthermore, by sliding the metal plate 6a with various slide structures using slide guides, slide ways, slide rails, etc., the height of the metal plate 6a can be changed, and the pointing characteristics can be easily changed. . The material of the metal case is not particularly ^{limited, 1. 0 X 1 0- 5} [Ω 'cm] metals Ya metal composite is a conductor of the following volume resistivity are preferred.

Fig. 9 (b) is a perspective view showing one embodiment of the metal case. The metal case has the shape of a truncated square pyramid with an open front, and the ends of adjacent metal plates 6a are all joined. I have. The inclination angle 0 of the metal plate 6a (see Fig. 9 (d)) is in the range of 0 ° <0 ≤ 90 ° from the extension direction of the ground conductor plate on the bottom of the stratified structure. The shape of the metal plate may be flat or curved. In addition, the ground conductor plate on the bottom surface for accommodating the stratified structure may have various shapes such as a circle, a polygon, and the like in addition to the rectangle. In addition, the shape of the ground conductor plate can be flat or curved. FIG. 9 (c) is a perspective view showing an embodiment in which the ends of the metal plates 6a are not joined. At this time, there is no change in the directivity even if the adjacent metal plates 6a are all joined or not joined. The metal plate 6a of this embodiment is rectangular, and the inclination angle 0 of the metal plate 6a (see FIG. 9 (d)) is 0 ° <0≤9 from the extension direction of the ground conductor plate on the bottom of the laminated structure. 0 ° range It is. The ratio of the length of the metal plate 6a to the length of the power supply element is preferably 1: 1 or more. Since it is not necessary to join the metal plate 6a, it is easy to manufacture, and the manufacturing cost can be reduced. By adjusting the height of the metal plate 6a and the inclination angle 0, desired directional characteristics can be obtained. In addition, the directivity can be easily changed by using a structure in which the height and the inclination angle 0 of the metal plate 6a can be changed.

As shown in FIG. 9 (d), the desired directivity can be changed by adjusting the angle of the metal plate.

Although it depends on the shape of the ground conductor plate on the bottom of the laminated structure, the required number of metal plates 6a is determined by desired characteristics. The electromagnetic radiation can be suppressed by providing the metal plate 6a in the direction where electromagnetic radiation is not required.

An electromagnetic wave absorber may be arranged on the side surface of the layered structure to absorb electromagnetic wave radiation to the side. A resin film containing a magnetic material such as ferrite can be used as the electromagnetic wave absorber.

In particular, as shown in FIG. 12, the laminated thin plate antenna of the present invention for the purpose of achieving a wide band, small size, and high gain includes a ground conductor plate 1 and a metal thin plate-shaped feed element disposed on the ground conductor plate. 2, a layered structure including a relatively thick dielectric plate 8 disposed apart from the feed element 2, and a thin metal plate parasitic element 4 disposed in close contact with the dielectric plate 8. In FIG. 12, the relatively thick dielectric plate 8 is arranged away from the power supply element 2, but may be in close contact with the power supply element. When the dielectric plate 8 is arranged at an appropriate distance from the feed element 2, the band is widened. In addition, the parasitic element 4 for narrowing the beam may be arranged away from the dielectric plate 8 for design reasons.

Due to the interposition of the dielectric plate 8, the wavelength of the electromagnetic wave becomes shorter than that in the air, so that the height of the stratified structure can be reduced and the size can be reduced. In addition, a plurality of resonance states of the resonance of the feed element and the resonance between the feed element and the dielectric plate occur, and the resonance band is expanded as a total resonance. Figures 13 and 14 show the characteristics. Here, the dielectric plate 8 is arranged at a distance of about 0.5 cm from the feeder element 2, the beam width in the horizontal plane is 38.5 degrees at 2.45 GHz, and the beam width is 38.5 degrees in the vertical plane. Has a beam width of 71 degrees. Figures 15 and 16 show the antenna characteristics when housed in a metal case that is open front. As is clear from Figs. 15 and 16, radiation to the side and rear is significantly suppressed. At 2.45 GHz, the beam width in the horizontal plane is 45 degrees, and the beam width in the vertical plane is 50 degrees.

The antenna according to the fourth embodiment of the present invention shown in FIG. 17 has four insulators at the periphery of a layered structure including a ground conductor plate 1, a feed element 2, and parasitic elements 3, 4, and 5. The stratified structure is integrally fixed with the support rod 9 attached thereto. The antenna according to the fifth embodiment of the present invention shown in FIG. 18 has a structure in which a conductor supporting rod 10 is attached to the central axis of the layered structure and the layered structure is integrally fixed. In the antenna according to the sixth embodiment of the present invention shown in FIG. 19, a low-permittivity spacer 11 is arranged between a ground conductor plate 1, a feed element 2, and parasitic elements 3, 4, 5. Then, the stratified structure is integrated. In the sixth embodiment, as shown in FIG. 17 or FIG. 18, an insulator support rod 9 or a conductor support rod 10 can be attached to fix the layered structure. Further, these laminated structures may be housed in a metal case as shown in FIG. 9, for example. Industrial applicability

According to the present invention, the gain of the communication antenna can be increased, and it is also effective for miniaturization. In addition, since the bandwidth is wide and the beam width can be narrow, directivity can be improved.

Claims

Range of request

1. A ground conductor plate, a feed element on a thin metal plate arranged on the ground conductor plate, a first thin metal plate parasitic element arranged approximately 0.01 to 0.2 wavelength from the feed element, An antenna, comprising: a layered structure including a metal sheet-shaped second parasitic element disposed at a distance of 0.2 to 0.8 wavelength from a power feeding element.

2. The antenna according to claim 1, wherein the stratified structure includes a third metal-plate-shaped third parasitic element disposed at a distance of 0.2 to 0.8 wavelength from the second parasitic element.

3. The stratified structure includes a metal thin plate-shaped parasitic element arranged at a distance of 0.2 to 0.8 wavelength from the third parasitic element. The number of parasitic elements after the fourth is the size of the ground conductor plate. 3. The antenna according to claim 2, wherein the antenna is determined by convergence of a beam aperture effect determined by the convergence.

4. The antenna according to claim 1, 2 or 3, wherein the feeding element and the parasitic element are strips, circular or square.

5. The antenna according to any one of claims 1 to 3, further comprising a metal case that is open front to accommodate the laminated structure.

6. The antenna according to any one of claims 1 to 5, wherein a radio wave absorber is disposed on a side surface of the layered structure.

7. A ground conductor plate, a thin metal feeder element disposed on the ground conductor plate, a dielectric plate spaced apart from or closely attached to the feeder element, and the dielectric plate An antenna comprising a layered structure including a metal-plate-shaped parasitic element disposed apart from or in close contact with a dielectric.

8. The layered structure includes a metal-plate-shaped parasitic element that is arranged at a distance of 0.2 to 0.8 wavelength from the first parasitic element, and the number of parasitic elements after the second depends on the size of the ground conductor plate. 8. The antenna according to claim 7, wherein the antenna is determined by convergence of a beam stop effect determined by the convergence.

9. The feed element and the parasitic element are strips, circles or squares. The antenna according to claim 7, wherein

10. The antenna according to claim 7, further comprising a metal case that is open front to accommodate the laminated structure.

11. The antenna according to claim 7, 8 or 9, wherein a radio wave absorber is arranged on a side surface of the layered structure.

1 2. A support rod made of a conductor or an insulator material is attached to the center axis of a layered structure composed of a ground conductor plate, a sheet metal feed element, and a sheet metal parasitic element, or the center axis of the layered structure. An antenna characterized in that a support rod of an insulating material is attached to a given position other than the above, and the laminated structure is integrally fixed.

13. A low dielectric constant spacer is arranged between the feeding element and the parasitic element of the laminated structure composed of the ground conductor plate, the feeding element in the form of thin metal sheet, and the feeding element in the form of thin metal sheet. An antenna characterized by being integrated.

14. A low dielectric constant space is provided between the feeder element and the parasitic element of the laminated structure including the ground conductor plate, the feeder element in the form of a thin metal plate, and the parasitic element in the form of a thin metal plate. And placing a support rod of conductor or insulator material on the central axis of the laminated structure, or attaching a support rod of insulating material at a given position other than the central axis of the laminated structure to attach the laminated structure. An antenna characterized by being integrally fixed.

15. The antenna according to claim 12, wherein the layered structure is the layered structure according to any one of claims 1 to 11.

16. The antenna according to claim 13, wherein the layered structure is the layered structure according to any one of claims 1 to 11.

17. The antenna according to claim 14, wherein the layered structure is the layered structure according to any one of claims 1 to 11.

1 8. A metal case with an open front that has a ground conductor plate at the bottom that houses the laminated structure and a metal plate that makes an angle of 0 (から is in the range of 0 ° <0 ≤ 90 °) from the extension direction. The antenna according to any one of claims 1 to 17, comprising:

19. The antenna according to claim 18, wherein the ground conductor plate on the bottom of the layered structure is formed in a circular, elliptical, or polygonal shape.

20. Of the metal plates that make an angle of 0 (0 is within the range of 0 ° <0 ≤ 90 °) from the extension direction of the ground conductor plate on the bottom that houses the laminated structure, the ends of adjacent metal plates are joined. The antenna according to claim 18 or 19, wherein the antenna has a structure that is not joined.

2 1. The ground conductor plate on the bottom that houses the laminated structure and the metal plate that forms an angle of 0 (0 is within the range of 0.0 ° <0≤90 °) from the extension direction are joined, and the tilt angle 0 can be changed. 21. The antenna according to claim 18, wherein the antenna has a structure in which the height can be changed by a structure in which a metal plate slides.

22. The antenna according to any one of claims 18 to 21, wherein the shape of the ground conductor plate on the bottom surface of the layered structure is flat or curved.

23. The metal plate which forms an angle 0 (0 is in the range of 0 ° <0≤90 °) from the extension direction of the ground conductor plate on the bottom surface that accommodates the laminated structure is flat or curved. 23. The antenna according to any one of 22.