WO2006018905A1

WO2006018905A1 - Antenna

Info

Publication number: WO2006018905A1
Application number: PCT/JP2004/013701
Authority: WO
Inventors: Hiroshi Takashima; Takio Tsubota
Original assignee: Sohdai Antenna Corporation
Priority date: 2004-08-20
Filing date: 2004-09-13
Publication date: 2006-02-23
Also published as: JP2006060561A

Abstract

A plane antenna (1) comprising at least two radiation parts 3 (3a, 3b) having the same shape and arranged on the same plane, and a feeding part (4) formed of a conductive material, arranged on the same plane as the radiation parts 3, and having a pair of terminal parts 8 (8a, 8b), one terminal part (8a) being connected with at least one radiation part (3a), the other terminal part (8b) being connected with the remaining radiation part (3b). Each radiation part (3) has a square flag element (7) comprising a square element (5) formed of a conductive material and having a closed loop shape, and a plurality of square flag elements (6) formed of a conductive material and each having a flag part (6a) of closed loop shape and a proximal end part (6b) extending from one side of the flag part (6a), the square element (5) and the flag elements (6) being arranged on the same plane, the proximal end part (6b) of the flag element (6) being connected with the edge part of the square element (5), the flag elements (6) being arranged line symmetrically to the square element (5), the line symmetric axes of the respective radiation parts 3 (3a, 3b) extending in different directions.

Description

Yuzuki Itoda β Antenna Branching Field

The present invention relates to an antenna, and more particularly, to an antenna that has a wide bandwidth with respect to terrestrial waves, has a wide directivity, is small and thin, and is suitable for shortening the wavelength. Background art

In recent years, with the development of radio wave utilization technology, the development of antennas has been diversified, and various devices such as Yagi antenna, rod antenna, loop antenna, and dipole antenna have already been developed and put into practical use. In particular, with the development of wireless devices and communication means, terrestrial digital TV broadcasting, wireless mopile, mobile phones,

With the practical use of IC tags, IC cards, etc., antennas have been developed that are used as communication means for such new small devices (for example, patent 2 0 0 2—

2 7 1 1 3 0).

However, the antennas used in the above-mentioned small devices need to be reduced in size and configured to be able to transmit and receive radio waves in all directions with wide directivity. However, many types of antennas have directivity in order to increase gain and performance, and in order to achieve omnidirectionality with such an antenna, it is necessary to make a composite antenna having multiple antennas. There was a problem that miniaturization / reduction of the antenna could not be achieved. Disclosure of the invention

The present invention has been made in view of the above-described problems, and has a wide bandwidth. The object is to provide an antenna that has wide directivity, is small and thin, and is suitable for shortening the wavelength.

In order to solve the above problems, an antenna according to the present invention includes a radiating element (for example, a square element 5 in the embodiment) having a closed loop shape and formed of a conductive material, a flag unit, and the flag. A plurality of flag elements formed of a conductive material having a base end portion protruding from the portion, the radiating element and the flag element are located on the same plane, and the base end portion of the flag element is the edge of the radiating element Are connected to each other, and have the same shape having a radiating flag element (for example, the square flag element 7 in the embodiment) arranged in line symmetry with respect to the radiating element, and located on the same plane. At least two radiating portions, and a pair of terminal portions that are located on the same plane as the radiating portion, and one of the terminal portions is connected to at least one radiating portion, and the other of the terminal portions is Remaining radiation part And a power feeding portion formed of a conductive material, and configured such that the axis of line symmetry of each radiating portion extends in a different direction.

In the antenna according to the present invention, each radiating portion is configured to have two or more radiating flag elements arranged in line symmetry, and the radiating flag elements constituting the radiating portion are arranged in the line symmetric axis direction. It is preferable that both ends are electrically connected.

At this time, it is desirable that the radiating element is formed in a square shape. Further, it is preferable that the flag portion of the flag element is formed in a square shape and a closed loop shape, and the base end portion is formed so as to extend by extending one side of the flag portion.

Further, it is preferable to have a loop element arranged on the same plane so as to surround the radiating portion, and to be configured such that an end portion of the loop element is connected to a terminal of the power feeding portion. At this time, even if part of the loop elements are constituted by cut good les ₀ Further, it is preferable that the power feeding unit includes a matching element which is formed in a square shape and in a closed loop shape so as to make the impedance a predetermined value. Furthermore, it is preferable that the power supply unit is configured to have a fill element that allows only a predetermined frequency to pass.

Furthermore, the antenna according to the present invention has two radiating portions (for example, the first and second radiating portions 3 a and 3 b in the embodiment), and the axis of line symmetry of each radiating portion is 9. It is preferably configured to be different by 0 degrees. Alternatively, it has four radiating parts (for example, the first to fourth radiating parts 2 3 a to 2 3 d in the embodiment), and each radiating part has a line symmetry axis that is different by 90 degrees. It is preferred that

By configuring the antenna according to the present invention as described above, the antenna can be planarized and miniaturized, which is suitable for a small communication device. In addition, since the radiating section is composed of a radiating element and a radiating flag element composed of a plurality of flag elements line-symmetrically connected to the radiating element, the frequency band that can be transmitted and received by this antenna is widened. In addition, the wavelength can be shortened. In addition, the antenna is configured to have two or more radiating portions and the direction in which the line symmetry axis extends is different, thereby widening the directivity of the antenna and allowing radio waves to be transmitted and received in all directions. Noh.

In addition, by combining the radiating section with a plurality of radiating flag elements, the sensitivity can be improved and the directivity of this antenna can be broadened, so that radio waves can be transmitted and received in all directions. You can.

In addition, by forming the radiating element that forms the radiating flag element in a square shape, or by forming the flag part of the flag element in a square shape and a closed loop shape, the optimum transmission / reception conditions can be set according to the frequency band, usage, etc. Can be set wear.

Furthermore, the gain of this antenna can be improved by providing a loop element so as to surround the radiating portion. The gain impedance can be adjusted by cutting a part of this loop element. Alternatively, by providing a matching element in the power feeding section, it is possible to adjust the impedance of this antenna and to widen the frequency band in which transmission and reception can be performed.

It should be noted that two radiating sections are arranged so that their line symmetry axes are 90 degrees apart, or four radiating sections are arranged so that their line symmetry axes are 90 degrees apart. By configuring the antenna according to the present invention, it is possible to effectively widen directivity and enable transmission / reception of radio waves in all directions. Brief Description of Drawings

FIG. 1 is a plan view showing the planar antenna according to the first embodiment.

FIG. 2 is a diagram showing the directivity of the radiating section, (a) is a diagram showing the directivity in the XY plane, and (b) is a diagram showing the directivity in the XZ plane. FIG. 3 is a diagram showing a planar antenna according to the second embodiment.

FIG. 4 is a plan view of the planar antenna according to the first embodiment when a loop element and a matching element are provided.

FIG. 5 is a plan view in the case where a loop element and a matching element are provided in the planar antenna according to the second embodiment.

FIG. 6 is a plan view of the planar antenna according to the first embodiment when a filter element is further provided.

FIG. 7 is a plan view of the planar antenna according to the second embodiment when a filter element is further provided. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Example 1

First, the first embodiment will be described with reference to FIG. The planar antenna 1 according to the first embodiment includes a substrate 2 made of a dielectric (insulator) and a conductive thin film (radiation) mounted on the plane of the substrate 2, that is, located on the same plane. Part 3 and power supply part 4).

In the planar antenna 1 configured as described above, the substrate 2 may be rigid or flexible, and the material thereof is not limited. For example, when the flexible substrate 2 is used, it can be mounted on a gentle curved surface such as a front glass or a clear glass of an automobile, or used for a flexible wireless IC card.

The radiating portion 3 is a square flag composed of a square element 5 having a square shape and a closed loop shape, and a plurality of flag elements 6 arranged in line symmetry on the side of the square element 5. The device 7 is configured. At this time, the flag element 6 is composed of a flag portion 6 a having a square shape and a closed loop shape, and a base end portion 6 b extending from one side of the flag portion 6 a. The rectangular flag element 7 extends so as to be orthogonal to the line symmetry axis X direction, and the base end 6 b is connected to the edge of the rectangular element 5.

In this first embodiment, the radiating section 3 has two square flag elements 7, which are arranged so that their line symmetry axes are parallel to each other, and their ends in the line symmetry axial direction are electrically connected. As a whole, the radiating section 3 is configured to be line symmetric with respect to the line symmetry axis Y. The number of the rectangular flag elements 7 constituting the radiating portion 3 is not limited to two, but may be one, or may be three or more. And in the first embodiment, the radiating part 3 has its line symmetry The first radiating portion 3a and the second radiating portion 3b are different in the direction in which the axis Y extends by 90 degrees. The first radiating portion 3a and the second radiating portion 3b have the same shape.

The power feeding unit 4 is formed of the same conductive material as that of the radiating unit 3, and a pair of terminal units 8 (8 a, 8 b) formed on the substrate 2 and a pair of terminal units 8 (8 a, 8 b) formed on the substrate 20. It is formed in a strip shape and is composed of each of the terminal portions 8a and 8b and the line portions 9 (9a and 9b) connecting the first and second radiating portions 3a and 3b. . The terminal 8 is connected to a feed line that connects the communication device and the planar antenna 1.

Since the material of the conductive thin film forming the radiating portion 3 and the power feeding portion 4 is not limited, copper, aluminum, carbon, or the like can be applied. It can also be formed using a conductive ink. As a method for forming such a thin film, an etching method such as a hot stamping method can be applied, and a strip-shaped metal foil is cut to a predetermined length and attached to the substrate 2. It is also possible to apply this method. Furthermore, when conductive ink is used, it is possible to apply a printing method.

In FIG. 1, the case where the conductive thin film portion (radiating portion 3 and feeding portion 4) is mounted on the substrate 2 has been described. However, when a large antenna is formed, a metal tube or a metal rod ( (Even if the cross section is circular or rectangular), it can be configured by connecting together, and in this way, sufficient shape retention performance is ensured for the conductive material that forms the pattern of the radiating section 3 and the feeding section 4 If possible, the substrate 2 can be omitted (the same applies to the following embodiments). In the planar antenna 1 having such a configuration, when an AC voltage in the radio frequency band is applied to the terminal portion 8 (8a, 8b) of the power feeding portion 4, the line portion 9 (9a, 9b) is used. This AC voltage is transmitted to the radiating parts 3a and 3b, and radio waves corresponding to the AC voltage are radiated from the radiating parts 3a and 3b. On the other hand, this planar antenna 1 is When the wave is irradiated, the AC voltage can be taken out from the terminal portion 8 (8a, 8b) of the feeding portion 4 according to the electromotive force generated in the radiating portions 3a, 3b.

Now, the directivity of the planar antenna 1 according to the first embodiment will be described with reference to FIG. Fig. 2 (a) shows the directivity on the XY plane when viewed from the side with the line symmetry axis B of one radiating part (3 a or 3 b) aligned with the Z axis. It has a circular directivity close to the character. On the other hand, Fig. 2 (b) shows the directivity on the XZ plane when the radiating part 3 a (3 b) is viewed from the top side, as well as left and right (X-axis direction) and rear (Z-axis direction). In the direction in which the power supply unit 4 is connected), the directivity is slightly weaker than the egg shape. Therefore, as shown in Fig. 1, by directing the axis of symmetry of the first radiating section 3a and the second radiating section 3b (the Z-axis direction in Fig. 2) in different directions, a highly directional part can be obtained. Directivity can be widened (slow directivity can be obtained) by making the planar antenna 1 as a whole closer to a circular shape in different directions.

Thus, the planar antenna 1 according to the first embodiment has a radiating portion 3 having a rectangular flag element 7 including a rectangular element 5 and a plurality of flag elements 6 connected to the rectangular element 5 in line symmetry. Therefore, it is possible to widen the frequency band that can be transmitted and received by this planar antenna 1 (for example, radio waves of 10 MHz to 10 GHz can be transmitted and received) and the wavelength can be shortened. is there. In addition, by combining the radiating section 3 with a plurality of square flag elements 7, the sensitivity is improved and the directivity shown in FIG. 2 is made more circular, that is, transmission / reception in all directions is possible. can do. As described above, according to the planar antenna 1 according to the first embodiment, it is possible to realize an antenna that has wide directivity, is small and thin, and is suitable for reduction. Moreover, the planar antenna 1 can easily cope with a wide band. In addition, this planar antenna 1 is a printed circuit board (a flexible printed circuit board). This planar antenna 1 can be formed in a partial region on the printed wiring board. That is, the planar antenna 1 can be mounted on a part of the printed wiring board on which the transmission / reception circuit is mounted in the same manufacturing process. Therefore, the entire transmission / reception apparatus including the planar antenna 1 can be reduced in size, and the manufacturing process can be simplified and the manufacturing cost can be reduced.

In addition, as shown in FIG. 1, the planar antenna 1 according to the first embodiment is configured so as to be located on the same plane as a whole, and therefore may be installed at a predetermined location by bonding or the like. Work can be facilitated. In addition, the planar antenna 1 attached by bonding has less risk of being damaged because there is no portion protruding to the outside. Example 2

Next, the planar antenna 21 according to the second embodiment will be described with reference to FIG. The planar antenna 21 according to the second embodiment is a case where the number of the two radiation portions 3 (3 a, 3 b) of the planar antenna 1 according to the first embodiment is four. Therefore, the configurations of the rectangular flag element 7 and the like described in the first embodiment are denoted by the same reference numerals and description thereof is omitted. Further, in FIG. 3, a substrate formed of an insulator is omitted and not shown. Each radiating portion 23 in the second embodiment has the same shape as each radiating portion 3 in the first embodiment. The radiating part 2 3 of this planar antenna 21 is composed of four radiating parts: a first radiating part 2 3 a, a second radiating part 2 3 b, a third radiating part 2 3 c, and a fourth radiating part 2 3 d. Each line symmetry axis direction is 90 degrees different from each other. The two line sections 9 a and 9 b constituting the power feeding section 4 have one (9 a) connected to the first and second radiating sections 2 3 a and 2 3 b and the other (9 b) The third and fourth radiating parts 2 3 c and 2 3 d are connected. Therefore, the first As in the embodiment, when an AC voltage in the radio frequency band is applied to the terminal portions 8 a and 8 b of the power feeding unit 4, the radiation units 2 3 a, 2 3 b, 2 3 c, This AC voltage is transmitted to 2 3 d, and radio waves corresponding to the AC voltage are radiated from the radiating parts 2 3 a, 2 3 b, 2 3 c, and 2 3 d. On the other hand, when the plane antenna 1 is irradiated with radio waves, an AC voltage is applied to the terminal section of the power feeding section 4 according to the electromotive force generated in the radiating sections 2 3 a, 2 3 b, 2 3 c, and 2 3 d. It can be taken out from 8 a and 8 b.

Since the directivities of the radiating parts 2 3 a, 2 3 b, 2 3 c, and 2 3 d constituting the planar antenna 21 are as described with reference to FIG. 2 in the first embodiment, In this way, by shifting the direction in which the line symmetry axis extends by 90 degrees, the directivity becomes almost circular, and transmission and reception in all directions can be made possible. Other effects are the same as in the first embodiment. Example 3

As described above, the planar antennas 1 and 2 1 according to the first and second embodiments are configured to have two or four radiating portions 3 and 23 and the direction in which the line symmetry axis extends. By changing the angle to 90 degrees, the directivity is close to a circle and transmission / reception is possible in all directions. In addition, the third example with improved sensitivity is shown in Figs. 7 will be used for explanation. As in the case of the second embodiment, the components already described are denoted by the same reference numerals and detailed description thereof is omitted. Also, a substrate formed of an insulator is not shown.

FIG. 4 shows a loop antenna 10 attached to the planar antenna 1 according to the first embodiment on the same plane so as to surround the radiating portion 3 (3 a, 3 b), and a plurality of rectangular and closed loop shapes. A planar antenna 3 1 provided with a matching element 1 1 is shown. The loop element 10 is attached so as to surround the radiating portions 3 a and 3 b in front of (the direction in which the feeding portion 4 is not connected) and the side. a, 9 b). The loop element 10 has a function of improving the gain in the radiation portions 3a and 3b.

On the other hand, the plurality of matching elements 11 are provided at a portion where the loop element 10 and the feeding portion 4 are connected, and have a function of adjusting the impedance of the planar antenna 31 to a desired value ( For example, when used for TV broadcast reception, the impedance should be 75 Ω). In addition, the matching element 11 has a different size from the closed loop of the rectangular element 5 and the flag element 6 of the radiating portions 3 a and 3 b, thereby widening the frequency band that can be transmitted and received by the planar antenna 31. Can do. For example, as shown in FIG. 4, by forming a larger element than the square element 5 or the flag element 6, the band can be expanded to the lower frequency side.

Thus, by providing the loop element 10 and the matching element 11, the gain of the planar antenna 31 can be improved and the frequency band can be widened. Also, the impedance of the planar antenna 31 can be adjusted to a desired value.

FIG. 5 is a plan view of the antenna mounted on the same plane so as to surround the radiating portion 2 3 (2 3 a, 2 3 b, 2 3 c, 2 3 d) on the planar antenna 21 according to the second embodiment. A planar antenna 41 having a pair of matching elements 1 1 and a plurality of matching elements 1 1 having a square shape and a closed loop shape is shown. Also in this planar antenna 41, the loop element 10 and the matching element 11 can improve the gain, widen the frequency band, and further adjust the impedance to a desired value.

Furthermore, the connection between the loop element 10 (matching circuit 11) and the feed section 4 (line sections 9a, 9b) as shown in the planar antennas 3 1 ', 4 1' shown in Figs. By providing the filter element 12 at the continuation part, it is possible to cut off unnecessary frequencies and transmit / receive only the desired frequency band with the planar antennas 3 1 ′ and 4 1 ′.

As shown in FIG. 6 and FIG. 7, the loop element 10 is cut partially and the first loop element 1 0a and the second loop element 1 connected to the line portions 9a and 9b, respectively. It is also possible to configure from 0b. Thus, by providing the loop element 10 with the gap 10 c, it is possible to adjust the gain of the planar antennas 3 1 ′ and 4 1 ′ and to adjust the impedance. In the case of the planar antennas 3 1 ′ and 4 1 ′ shown in FIGS. 6 and 7, a coaxial cable is connected to the terminal portions 8 a and 8 b of the power feeding unit 4. 2 Connect the core wire of the coaxial cable to the terminal section 8a directly connected to 3 and connect the shielded cable of the coaxial cable to the terminal section 8b connected to the radiating sections 3 and 2 3 via the filter element 12.

In the first and second embodiments described above, the description has been given of the case where both the square element 5 and the flag portion 6a of the flag element 6 are formed in a square shape and a closed loop shape. For example, the square element 5 may be circular, oval, polygonal, or square, and may be formed in a closed loop shape, or the flag portion 6 a of the flag element 6 a. May be formed in a circular, elliptical, polygonal, or square shape. Further, the flag portion 6a may not be in a closed loop shape, and may be configured such that the entire surface is formed of a conductive material.

Claims

Scope of wording

1. a radiating element having a closed loop shape and made of a conductive material, and a flag part and a plurality of flag elements made of a conductive material having a base end part protruding from the flag part, The radiating element and the flag element are located on the same plane, the base end portion of the flag element is connected to an edge of the radiating element, and the flag elements are arranged in line symmetry with respect to the radiating element. At least two radiating portions having the same shape and having the same radiation flag element and located on the same plane;

Located on the same plane as the radiating portion, has a pair of terminal portions, one of the terminal portions is connected to at least one radiating portion, and the other of the terminal portions is connected to the remaining radiating portion. An antenna comprising: a power feeding portion formed of a conductive material, wherein the axis of line symmetry of each of the radiating portions extends in different directions.

2. Each of the radiating portions is configured to have two or more of the radiating flag elements arranged in line symmetry, and both ends of the radiating flag elements constituting the radiating portion in the line symmetric axis direction are electrically The antenna according to claim 1, wherein the antenna is configured to be connected to each other.

3. The antenna according to claim 1 or 2, wherein the radiating element is formed in a square shape.

4. The flag portion of the flag element is formed in a square shape and a closed loop shape, and the base end portion is formed to extend by extending one side of the flag portion. The antenna according to any one of claims 1 to 3.

5. It has a loop element arranged on the same plane so as to surround the radiation part, and an end of the loop element is connected to the terminal of the power feeding part, respectively. The antenna according to any one of claims 1 to 4.

6. The antenna according to claim 5, wherein a part of the loop element is cut.

7. The power feeding unit is configured to include a matching element that has a square shape and is formed in a closed loop shape so that the impedance is set to a predetermined value. Antenna described in.

8. The antenna according to any one of claims 1 to 7, wherein the power feeding unit includes a filter element that allows only a predetermined frequency to pass therethrough.

9. The antenna according to any one of claims 1 to 8, wherein the antenna has two radiating portions, and each radiating portion has a line symmetry axis different by 90 degrees.

9. The antenna according to claim 1, wherein the antenna has four radiating portions, and each radiating portion has a line symmetry axis that is different by 90 degrees.