JP2006279421A - Linear small-sized antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna with a high degree of design freedom, configured to cope with multi-products and attaining downsizing and broadband. <P>SOLUTION: A linear conductor 2 is wired and formed on an adhesive sheet 5 to be nearly fractal shapes by using a second order Minkowski shape or the like. Since the linear conductor 2 can freely be wired on the adhesive sheet 5, the antenna has a high degree of design freedom and can cope with multi-products and also, the antenna employing the linear conductor 2 shows nearly fractal shapes, and a comparative broadband and downsizing can be realized. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a linear antenna that has a high degree of freedom in antenna design and can be widened and reduced in size.

As a method for manufacturing an antenna, molding by a mold or etching is generally used. However, once the antenna shape is determined, it is difficult to change.

For example, it is necessary to prepare a mold suitable for each antenna shape in molding using a mold, and a mask suitable for each antenna shape in manufacturing using etching. Therefore, there is a big problem in terms of cost and production period for products such as mobile phones whose antenna shape changes depending on the model.

As shown in Patent Document 1, a linear antenna device is disclosed in which a linear conductor in which a conductor is covered with an insulator is adapted to the antenna technology. According to this disclosed technique, in order to optimize the impedance characteristic of the antenna, the linear conductor can be freely wound around the flat sheet on which the linear conductor is arranged.

Therefore, the degree of freedom of design is greatly increased, and adapting to a wide variety of antennas, especially a small amount of a wide variety of antennas, is a very effective manufacturing means.

As a method of widening the bandwidth, Patent Document 2 discloses an antenna using a fractal shape using a shellpinski figure.
JP 2004-080108 A Japanese translation of PCT publication No. 2003-510871

The purpose is to provide a product that can be reduced in size and widened in a form that has a high degree of design freedom and can be used for a wide variety of products. However, although the antenna device described in Patent Document 1 describes the use of a linear conductor, there is no description regarding the antenna shape.

In addition, the fractal shape described in Patent Document 2 uses a shell pinski figure, and the figure itself has a surface configuration, and there is a problem that it cannot be applied to a linear antenna.

A first aspect of the present invention is a linear small antenna in which a linear conductor is formed in a substantially fractal shape on a flat sheet.

According to a second aspect of the present invention, there is provided a linear small antenna characterized in that a linear conductor in which an insulating film is formed on the linear conductor is formed in a substantially fractal shape on a flat sheet.

  According to a third aspect of the present invention, there is provided a linear small antenna device characterized in that the linear conductors intersect or contact each other.

  A fourth aspect of the present invention is a linear small antenna characterized in that a start point and an end point of the fractal shape are adjacent to each other.

A fifth aspect of the present invention is a linear small antenna characterized in that the fractal shape is a Minkowski-like shape.

According to a sixth aspect of the present invention, there is provided a small linear antenna characterized in that the linear conductor is manufactured using a wiring machine.

In the first and second aspects, since the antenna using the linear conductor has a fractal shape, it is possible to realize a relatively wide band and a small size.

In the third aspect, the degree of freedom of the antenna shape is further increased by crossing or contacting the linear conductors, and the size can be reduced.

In the fourth and fifth aspects, by connecting the start point and end point of the fractal shape adjacent to each other, the adjacent start point and end point are connected to be in a closed state, or the start point and end point are not connected to be in an open state, etc. Can be switched.

In the sixth aspect, the wire conductor is used to form the fractal shape using the linear conductor, so that simple manufacturing is possible, and designing and manufacturing is easy even for various types of antenna shapes. It becomes possible.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
In addition, about each structure part which has the same function, the same code | symbol is attached | subjected and demonstrated for simplification of illustration and description.

The order shown below shows the repetition of the fractal shape. FIG. 9 is an explanatory diagram of the order of the Minkowski shape. FIG. 9 shows the first Minkowski shape 30, the second Minkowski shape 31, and the third Minkowski shape. A ski shape 32 is shown. As the order increases, the density of the linear conductor in the same area tends to increase.

Example 1
FIG. 1 is a diagram for explaining a linear small antenna using a secondary Minkowski shape.
Here, as an antenna for the 300 MHz band, a secondary Minkowski shape was selected in order to secure a receiving efficiency of 10% and make it as small as possible.

First, a substrate (not shown) made of a polyethylene terephthalate (PET) film having a thickness of 50 μm that has been subjected to a release treatment, and an adhesive layer in which a thermosetting modified epoxy resin adhesive having a thickness of 40 μm is applied on the substrate ( (Not shown) is formed. Subsequently, the wire conductor 2 having a diameter of 30 μm was laid on the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet with a wiring machine. At this time, the start point lead portion 3 and the end point lead portion 4 were configured to have extra lengths for connection to other electronic components, and the terminals 6 were attached to the tips thereof. The starting point lead part 3 to the ending point lead part 4 are continuously wired in the manner of one-stroke writing. However, the start point lead part 3 and the end point lead part 4 are not connected (open state).

Subsequently, the wired adhesive sheet was pressed for about 1 hour under the conditions of a temperature of 150 ° C. and a pressure of 1.96 × 10 ⁵ Pa to completely cure the adhesive. Removal of the linear small antenna 1 was completed.

In addition to the above method, a base film or the like may be bonded to the surface where the linear conductor 2 is wired after the linear conductor 2 is wired. The pressure-sensitive adhesive sheet may be other than the above as long as the linear conductor 2 can be wired. For example, a flexible material in which a rubber-based pressure-sensitive adhesive layer, a silicon-based pressure-sensitive adhesive layer, an acrylic pressure-sensitive adhesive layer, a UV curable acrylic pressure-sensitive adhesive layer, or the like is provided on a base material made of polyester, polyimide, polypropylene, or the like may be used.

The total length of the linear conductor required to form the Minkowski shape was 332 mm. Also, the length L of one side of the substantially square occupied by the Minkowski shape was 31 mm, and a very small linear antenna was realized.

FIG. 2 is a diagram for explaining an antenna device on which the linear small antenna 1 is mounted. The antenna device in which the linear small antenna 1 is connected to an electronic circuit board 7 that performs high-frequency circuit processing via a terminal 6 and is housed in a housing. It is.

As antenna characteristics, the resonance frequency f0 was 325 MHz, and the band Δf below VSWR 3.0 was 18 MHz.

(Example 2)
In addition, when the insulating film was formed on the linear conductor 2, the same characteristics as those shown in Example 1 were obtained.

(Example 3)
FIG. 3 is a diagram for explaining the intersecting shape of the linear conductors 2, and 11 is a Minkowski-shaped antenna in which the corner portions 9 of the linear conductors 2 having a Minkowski shape intersect or contact each other. This makes it possible to further reduce the length L of one side of the substantially square occupied by the Minkowski shape.
Further, as the antenna characteristic, the resonance frequency f0 tends to shift slightly toward the low frequency side, but is not so much affected.

FIG. 4 is a diagram for explaining the relationship between the total length of the linear conductor and the resonance frequency. There is almost no difference in resonance frequency between Minkowski-shaped resonance frequency 12 in which corner portion 9 has intersection or contact and Minkowski-shaped resonance frequency 13 in which corner portion 9 has no intersection or contact. .

Example 4
Further, if the state where the start point lead portion 3 and the end point lead portion 4 are connected is a closed state, and the state where the start point lead portion 3 and the end point lead portion 4 are not connected is an open state, the resonance frequency characteristics change depending on the connection state.
FIG. 5 shows the resonance frequency characteristic 14 of the Minkowski-shaped antenna with the start point lead 3 and the end-point lead 4 closed, and the resonance of the Minkowski-shaped antenna with the start-point lead 3 and the end-point lead 4 open. In the comparison of the frequency characteristics 15, the resonance frequency characteristic 14 of the Minkowski-shaped antenna with the start point lead part 3 and the end point lead part 4 in the closed state is the min frequency with the start point lead part 3 and the end point lead part 4 in the open state. Compared to the resonance frequency characteristic 15 of the Kawsky-shaped antenna, the resonance frequency is increased by about 300 MHz.

FIG. 6 shows a VSWR 3.0 or lower band (MHz) 16 of the Minkowski-shaped antenna in which the start point lead part 3 and the end point lead part 4 are in a closed state, and a minkowski shape antenna with a start point lead part 3 and an end point lead part 4 in an open state. It is the figure which shows VSWR3.0 or less zone | band (MHz) 17 of a Kowsky-shaped antenna.

The band below VSER3.0 is greatly increased by making the closed state. Considering these characteristics, it is possible to operate as an antenna that covers both bands by adding a switch function to make the connection state of the start point lead part 3 and the end point lead part 4 open and closed. .

Further, the fractal shape can be related to the resonance frequency and the size L of the actual square of the actual antenna from the repeated shape of the similar pattern.
FIG. 7 is a diagram for explaining the relationship between the antenna dimensions determined by the Minkowski shape and the resonance frequency. When the linear conductor diameter is 0.03 mm, the length L of one side of the substantially square antenna and the resonance frequency are shown. It is a relationship diagram. 20 is a diagram showing the relationship between the resonance frequency in the case of the primary Minkowski shape and the length L of one side of the substantially square Minkowski shape, and 19 is the relationship between the resonance frequency and the substantially square shape in the case of the secondary Minkowski shape. A relationship diagram of the length L of one side of the Minkowski shape, and 18 shows a relationship diagram of the resonance frequency in the case of the tertiary Minkowski shape and the length L of one side of the substantially square Minkowski shape. . As a result, if the resonance frequency is determined, the size of the antenna can be determined.

(Example 5)
FIG. 8 is an example in which an antenna is mounted on the rear glass of the vehicle, and is an explanatory diagram in which a very wide band antenna used for terrestrial digital broadcasting or the like is mounted on the rear glass 25 of the vehicle. Resonant frequency f0 = 485 MHz, VSER 3.0 or lower band Δf = 50 MHz, Resonant frequency f0 = 535 MHz, VSER 3.0 or lower band Δf = 70 MHz, Resonant frequency f0 = 610 MHz, VSER 3.0 or lower band Δf = 100 MHz, Resonant frequency f0 = 720 MHz The four antennas 24, 23, 22, 21 having a band Δf = 120 MHz below VSER 3.0 are created in a Minkowski shape, and a switching device (not shown) for selecting an antenna that receives a signal in each band is used. Accordingly, it is possible to provide a very thin and simple broadband antenna for a vehicle.

The figure explaining the linear small antenna using a secondary Minkowski shape The figure explaining the antenna device carrying the linear small antenna 1 The figure explaining the cross shape of the linear conductor 2 The figure explaining the relationship between the full length of the linear conductor 2, and a resonance frequency The resonance frequency characteristic 15 of the Minkowski-shaped antenna with the start point lead part 3 and the end point lead part 4 closed, and the resonance frequency characteristic 16 of the Minkowski shape antenna with the start point lead part 3 and the end point lead part 4 open. Figure comparing VSWR 3.0 or lower band (MHz) 17 of the Minkowski shaped antenna with the start point lead part 3 and the end point lead part 4 closed, and the Minkowski shape antenna with the start point lead part 3 and the end point lead part 4 open. It is the figure which shows the band (MHz) 18 below VSWR3.0. The figure explaining the relationship between the antenna dimensions and resonance frequency determined by the Minkowski shape An example of mounting an antenna on the rear glass of a vehicle Explanatory drawing of Minkowski shape order

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Linear small antenna 2 ... Linear conductor 3 ... Start point lead part 4 ... End point lead part 5 ... Adhesive sheet 6 ... Terminal 7 ... Electronic circuit board 8 ... -Housing 9 ... Corner portion 10 ... Minkowski shape 11 not intersecting or contacting 11 ... Minkowski shape where corner portion 9 of linear conductor 2 forming Minkowski shape intersects or contacts Antenna 12 ... Minkowski-shaped resonance frequency at which the corner portion 9 intersects or contacts
13... Minkowski-shaped resonance frequency 14 in which the corner portion 9 has no intersection or contact 14... Resonance frequency characteristic 15 of the Minkowski-shaped antenna with the start point lead portion 3 and the end point lead portion 4 closed. ... Resonance frequency characteristic 16 of Minkowski-shaped antenna with start point lead 3 and end-point lead 4 open. ... of Minkowski-shaped antenna with start-point lead 3 and end-point lead 4 closed. VSWR 3.0 or lower band (MHz)
17 ... Minusky shaped antenna VSWR 3.0 or less band (MHz) with the start point lead part 3 and the end point lead part 4 open
18 ... Relationship between the resonance frequency in the case of a tertiary Minkowski shape and the length of one side of the substantially square Minkowski shape. 19 ... The resonance frequency in the case of a secondary Minkowski shape. Fig. 20 shows the relationship between the length of one side of the square Minkowski shape and the relationship between the resonance frequency in the case of the primary Minkowski shape and the length of one side of the nearly square Minkowski shape. -Resonance frequency f0 = 720MHz, VSER 3.0 or less band Δf = 120MHz
22: Resonance frequency f0 = 610 MHz, VSER 3.0 or less band Δf = 100 MHz
23: Resonance frequency f0 = 535 MHz, VSER 3.0 or less band Δf = 70 MHz
24: Resonance frequency f0 = 485 MHz, VSER 3.0 or less band Δf = 50 MHz
25 ... Vehicle rear glass 30 ... Primary Minkowski shape 31 ... Secondary Minkowski shape 32 ... Tertiary Minkowski shape

Claims (6)

A small linear antenna in which a linear conductor is formed in a substantially fractal shape on a flat sheet. 2. The small linear antenna according to claim 1, wherein the linear conductor is a linear conductor having an insulating film formed thereon.   3. The small linear antenna according to claim 2, wherein the linear conductors intersect or contact each other.   The linear small antenna according to any one of claims 1 to 3, wherein a start point and an end point of the fractal shape are adjacent to each other.   The linear small antenna according to any one of claims 1 to 4, wherein the fractal shape is a Minkowski shape. The said linear conductor is produced using a wiring machine, The linear small antenna as described in any one of Claim 1 thru | or 5 characterized by the above-mentioned.

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