JP2005218080A - Antenna system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an antenna system which is simple in structure and is easy to mount. <P>SOLUTION: This antenna system 10 constitutes a biconical antenna. Two conical internal spaces are formed so that respective vertexes face each other to be matched respective rotating center axes with each other in a cylindrical dielectric base material. A first antenna element 11 is formed on one inner circumferential surface, and a second antenna element 12 is formed on the other inner circumferential surface so as to be separated from the first antenna element 11. A signal is fed by using the vertexes of the first and second antenna elements 11 and 12 as a feeding point P. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an antenna device, and more particularly to an antenna device suitable for use in a broadband communication system, an ultra-wideband communication system, and the like.

  Since a wide frequency band can be used at frequencies above the microwave band, a broadband wireless system suitable for high-speed transmission of large-capacity data such as images can be realized. In recent years, development toward the realization of communication technology that enables further broadband and high-speed communication has been underway. As one of means for wirelessly performing such high-speed information transmission, a communication system (UWB wireless system) using an ultra wide band (UWB) wireless technology has attracted attention.

  Since the UWB wireless system uses a very wide frequency band of several gigahertz width or more, the frequency characteristics of the antenna device to be used is, for example, an extremely wide band extending from the lower limit frequency to a frequency range of about 2 to 10 times the frequency range. Is required.

  As an antenna device having such a broadband characteristic, for example, there are a discone antenna, a biconical antenna, a brown antenna, a conical whip antenna, and the like. These antenna devices are configured by a combination of antenna elements (generally a combination of two antenna elements having the same or different shapes) composed of metal conductors in the form of rods, columns, cylinders, cones, or disks. The

  FIG. 8 shows the structure of a discone antenna. As shown in the figure, the discone antenna has a conical conductor element 21 and a predetermined interval on the apex side of the conical conductor element 21 so that the rotation center axis coincides with the rotation center axis passing through the apex of the conical conductor element 21. And disc conductor elements 22 arranged in close proximity to each other. Then, the coaxial cable 14 feeds a signal with the center of the disk conductor element 22 as the feeding point P, and feeds the ground potential with the apex of the conical conductor element 21 as the feeding point P.

  FIG. 9 shows the structure of the biconical antenna. The biconical antenna is composed of two conical conductor elements 23 and 24, in which the rotation center axes passing through the respective apexes coincide with each other, and the apexes are opposed to each other with a predetermined distance therebetween. It is. Then, a signal is fed with each vertex as a feeding point P.

  FIG. 10 shows the structure of the brown antenna. The brown antenna is a columnar conductor element that is arranged close to the apex side of the conical conductor element 25 at a predetermined interval so that the rotation center axis coincides with the conical conductor element 25 and the rotation center axis passing through the apex of the conical conductor element 25. It is comprised with the conductor element 26. FIG. A signal is fed with the end of the columnar conductor element 26 as the feeding point P, and a ground potential is fed with the apex of the conical conductor element 25 as the feeding point P.

  Here, FIG. 11 and FIG. 12 show an example of the structure at the actual product level in the antenna element constituting the antenna device. In FIG. 11, the conical conductor element 21 is composed of a linear annular conductor portion 21a and a plurality of linear radial conductor portions 21b arranged at equal intervals connecting the annular conductor portion 21a and the apex. It is configured. In FIG. 12, in addition to the conical conductor element 21, the disk conductor element 22 connects the linear annular conductor portion 22 a and the annular conductor portion 22 a and the center point at equal intervals. And a plurality of linear radial conductor portions 22b arranged on the surface.

  As described above, when the antenna element is configured by a linear member, a wire is used by using an accessory member such as a separator made of an insulator such as a fluororesin or an ABS resin so as to have a desired antenna shape and configuration. It is necessary to fix and hold the element constituent member which is a shaped member. This complicates the structure and requires a lot of man-hours for mounting.

  As a technique for solving such structural and mounting problems, for example, Japanese Patent Application Laid-Open No. 2001-313514 discloses an antenna in which a cylindrical body is subjected to helical plating.

JP 2001-313514 A

  However, the above-described technique only shows one of the antenna elements, and an antenna device that transmits and receives signals cannot be configured as it is.

  Accordingly, an object of the present invention is to provide an antenna device that has a simple structure and can be easily mounted, and a wireless communication device using the antenna device.

  The antenna device of the present invention has a cylindrical or frustoconical outer shape, a first conical space is formed on one bottom surface side, and the first conical space and the apex face each other on the other bottom surface side. A dielectric base material formed with two conical spaces, a first antenna element formed on the inner peripheral surface of the first conical space, and a first antenna element on the inner peripheral surface of the second conical space. And a second antenna element formed separately. In this antenna device, it is preferable that the rotation center axes of the first and second conical spaces coincide with each other. In addition, one of the vertices of the first antenna element 11 and the second antenna element 12 may be a feeding point to which a signal from a signal source is fed, and the other may be a feeding point to which a ground potential is fed. preferable.

  As described above, according to the antenna device of the present invention, since the first antenna element and the second antenna element are formed and integrated on the dielectric base material, the element constituent member and the accessory member Thus, there is no need to assemble an antenna element having a desired shape, and an antenna device that can be mounted as it is with a simple structure is obtained.

  Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings. Here, in the accompanying drawings, the same reference numerals are given to the same members, and duplicate descriptions are omitted. The embodiment of the invention is a particularly useful embodiment in which the present invention is implemented, and the present invention is not limited to the embodiment.

  FIG. 1 is a perspective view showing a partially broken antenna device according to an embodiment of the present invention. FIG. 2 is a perspective view showing a partially broken antenna device according to another embodiment of the present invention. FIG. 3 is a perspective view showing a partially broken antenna device according to still another embodiment of the present invention. FIG. 4 is a partially broken view of the antenna device according to still another embodiment of the present invention. FIG. 5 is a perspective view showing an antenna device according to still another embodiment of the present invention, and FIG. 6 is a partially cutaway view showing an antenna device according to still another embodiment of the present invention. FIG. 7 is a perspective view showing a partially broken antenna device according to still another embodiment of the present invention.

  As shown in FIG. 1, the antenna device 10 of the present embodiment forms a discone antenna and has a columnar substrate 10a made of a dielectric. A conical internal space is formed in the base material 10a, and a first antenna element 11 in which a metal conductor layer is patterned is formed on the inner peripheral surface thereof. In addition, on the flat surface facing the outside of the base material 10a, the second antenna element 12 in which the metal conductor layer is similarly circularly patterned is spaced apart from the first antenna element 11 by a predetermined distance. The antenna element 11 is formed on the apex side. And the 1st antenna element 11 and the 2nd antenna element 12 are arrange | positioned so that each rotation center axis may mutually correspond.

  In addition, as a dielectric material which comprises the base material 10a, for example, ceramic (cordylite, forsterite, alumina, glass-based ceramic, titanium oxide-based ceramic, or a mixture thereof), resin (polytetrafluoroethylene, polyimide, bis) Maleimide, triazine, liquid crystal polymer, etc.) or a composite material of ceramic and resin.

  When such an antenna device 10 is built in a wireless communication device, the first antenna element 11 is mounted so as to face a mounting surface of a substrate (not shown). Then, as shown in the drawing, a signal is fed from a signal source (not shown) with the center of the second antenna element 12 as a feeding point P by a coaxial cable 14 as a feeding line, and the apex of the first antenna element 11 is reached. The ground potential is fed using the feed point P as the power supply point P. In the case of the discone antenna shown in FIG. 1, resonance is obtained in a wide frequency band of about 4 to 8 times the lowest frequency at which the antenna resonates.

  The electrodes constituting the first antenna element 11, the second antenna element 12, and the feeding point P are formed by patterning a metal conductor layer such as copper or silver. Specifically, for example, a method of pattern printing a metal paste such as silver, a method of forming a metal pattern layer by plating, a method of patterning a thin metal film by etching, a method of mounting a metal created by sheet metal processing, etc. It is formed by.

  In addition, including the case described below, the first antenna element 11 may be grounded and a signal may be supplied to the second antenna element 12.

  In addition to FIG. 1 and FIG. 6 described later, the coaxial cable 14 is omitted for simplification of illustration. In addition, a feed line such as a coaxial cable is not essential for the antenna device of the present invention.

  As described above, according to the antenna device 10 of the present embodiment, the first antenna element 11 and the second antenna element 12 are formed and integrated on the dielectric base material 10a. There is no need to assemble an antenna element having a desired shape by using the constituent elements of the antenna element and the attached member as in the antenna device. Therefore, it becomes a simple structure and the antenna device 10 can be mounted on the substrate as it is.

  In addition, since the first antenna element 11 is formed on the inner peripheral surface of the base material 10a, the possibility that the first antenna element 11 is damaged when the antenna device 10 is handled or mounted on the substrate is alleviated. .

  The antenna device 10 described above may be mounted so that the mounting direction is reversed as shown in FIG. 2 and the second antenna element 12 faces the mounting surface of a substrate (not shown). In this case, a signal is fed to the first antenna element 11 and a ground potential is fed to the second antenna element 12.

  Next, a case where the antenna device of the present invention is applied to a device other than a discone antenna will be described.

  The antenna device 10 shown in FIG. 3 forms a biconical antenna. Two cylindrical inner spaces are arranged at the apexes of the cylindrical base material 10a so that the respective rotation center axes coincide with each other. Are formed facing each other. A first antenna element 11 is formed on one inner peripheral surface, and a second antenna element 12 is formed on the other inner peripheral surface. In the antenna device 10 shown in FIG. 3, signals are fed with the apexes of the first antenna element 11 and the second antenna element 12 as feeding points P.

  Next, the antenna device 10 shown in FIG. 4 forms a brown antenna. A conical internal space is formed in the columnar base material 10a, and the first antenna element 11 is formed. A cylindrical hole is formed so that the rotation center axis coincides with the rotation center axis of the first antenna element 11, and a second metal layer is patterned on the inner peripheral surface of the hole. An antenna element 12 is formed. In the antenna device 10 shown in FIG. 4, the apex of the first antenna element 11 and the end of the second antenna element 12 on the first antenna element 11 side are the feeding points P.

  Although the antenna device 10 shown in FIG. 5 forms a discone antenna, the base material 10a has a truncated cone shape. Thus, the shape of the base material 10a may be a truncated cone. Furthermore, in the present invention, the base material 10a is not limited to the truncated cone shape shown in FIG. 5 or the columnar shape shown in FIGS. 1 to 4, but has a cylindrical shape, a pyramid shape, a truncated pyramid shape, or the like. be able to.

  In addition, the antenna element formed on the peripheral surface is not limited to a conical shape, and includes various shapes such as a pyramid shape, a columnar shape (a columnar shape and a polygonal columnar shape), a tubular shape (a cylindrical shape and a polygonal cylindrical shape), and a spiral shape. It can be a three-dimensional shape. As long as it is formed in a three-dimensional shape, it does not have to be formed over the entire circumferential direction. Further, the antenna element formed on the flat surface may be planar, and may be square, rectangular, elliptical, circular, or various other two-dimensional shapes.

  The shape of these antenna elements can be formed by patterning a metal conductor layer on the entire surface along the shape. For example, a large number of linear metal conductor layers can be formed radially from one point. Alternatively, a conical shape or a circular shape may be formed, or a desired shape may be configured with a mesh structure. Note that in this specification, the conical shapes such as the conical shape and the pyramid shape include a truncated cone shape and a truncated pyramid shape in which the apex portion is missing.

  In the above description, at least one of the first antenna element 11 and the second antenna element 12 is formed on the inner peripheral surface of the base material 10a. However, as shown in FIG. You may form in the outer peripheral surface. In the figure, one antenna element is formed on the outer peripheral surface, but two antenna elements can also be formed on the outer peripheral surface.

  Further, the antenna device 10 may be provided with a parasitic third antenna element 13 to which neither a signal nor a ground potential is fed. That is, for example, in the dipole antenna shown in FIG. 7, the cylindrical first antenna element 11 and the second antenna element 12 are respectively formed in two internal spaces formed from both ends of the cylindrical base material 10a. In the state mounted in the wireless communication device, the signal and the ground potential are respectively fed by the coaxial cable 14 with the end face of each of the cylindrical antenna elements 11 and 12 as the feeding point P. And the 3rd antenna element 13 is formed in the outer peripheral surface of the base material 10a at the space | interval for the thickness of the 1st antenna element 11 and the 2nd antenna element 12, and the base material 10a.

  By providing such a parasitic third antenna element 13, the antenna device 10 can be tuned to desired antenna characteristics.

  In FIG. 7, the third antenna element 13 is formed on the outer peripheral surface of the base material 10a, but it can also be formed on the inner peripheral surface or a flat surface. Also, the shape can be freely set.

  The antenna device 10 described above can be mounted on various wireless communication devices such as a mobile phone, a mobile terminal, and a built-in antenna of a wireless LAN card.

1 is a perspective view showing a partially broken antenna device according to an embodiment of the present invention. It is a perspective view which fractures | ruptures and shows the antenna apparatus which is other embodiment of this invention. It is a perspective view which fractures | ruptures and shows the antenna apparatus which is further another embodiment of this invention. It is a perspective view which fractures | ruptures and shows the antenna apparatus which is further another embodiment of this invention. It is a perspective view which shows the antenna apparatus which is further another embodiment of this invention. It is a perspective view which fractures | ruptures and shows the antenna apparatus which is further another embodiment of this invention. It is a perspective view which fractures | ruptures and shows the antenna apparatus which is further another embodiment of this invention. It is explanatory drawing which shows the structure of a discone antenna. It is explanatory drawing which shows the structure of a biconical antenna. It is explanatory drawing which shows the structure of a brown antenna. It is explanatory drawing which shows another example of the structure of a discone antenna. It is explanatory drawing which shows another example of the structure of a discone antenna.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Antenna apparatus, 10a ... Base material, 11 ... 1st antenna element, 12 ... 2nd antenna element, 13 ... 3rd antenna element, 14 ... Coaxial cable, P ... Feeding point.

Claims (3)

It has a cylindrical or frustoconical outer shape, a first conical space is formed on one bottom surface side, and a second conical space is formed on the other bottom surface side with the first conical space facing the apex. A dielectric substrate,
A first antenna element formed on an inner peripheral surface of the first conical space;
An antenna device comprising: a second antenna element formed on an inner peripheral surface of the second conical space so as to be separated from the first antenna element. The antenna device according to claim 1, wherein the first and second conical spaces are formed such that respective rotation center axes thereof coincide with each other. Of the vertices of the first antenna element 11 and the second antenna element 12, one is a feeding point to which a signal from a signal source is fed, and the other is a feeding point to which a ground potential is fed. The antenna device according to claim 1 or 2.

Images