JP3949292B2 - antenna - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antenna, and more particularly to a screen door to which an antenna having a function of shielding or enhancing a predetermined frequency according to the purpose is added, and shielding an electromagnetic wave having a specific frequency regardless of its polarization plane. Alternatively, the present invention relates to a screen door antenna that can be enhanced.
[0002]
[Prior art]
Along with the widespread use of mobile communications, problems such as electromagnetic interference suddenly surfaced, and when shielding from the outside space is necessary for effective use of electromagnetic waves in communication inside buildings, or equipment in specific places such as hospitals In some cases, it is necessary to shield electromagnetic waves in order to avoid malfunctions.
[0003]
[Problems to be solved by the invention]
In order to prevent electromagnetic waves from entering a building or the like, an electromagnetic wave shielding material or the like may be used for a wall surface or a window glass. However, electromagnetic waves are usually inevitable when a screen door is used.
[0004]
On the other hand, there is a case where it is necessary to increase the sensitivity of communication, but there are almost no cases where an enhancement function is added to a screen door or the like.
[0005]
Therefore, a first technical problem of the present invention is to provide an antenna that can exhibit characteristics regardless of the polarization plane of the incoming radio wave.
[0006]
The second technical problem of the present invention is to provide an antenna capable of shielding or enhancing electromagnetic waves of a specific frequency.
[0007]
Furthermore, the third technical problem of the present invention is to provide a screen door type antenna provided with the antenna in a screen door of a building.
[0008]
[Means for Solving the Problems]
According to the present invention, it is substantially composed of a base made of a net provided with at least one loop-shaped parasitic element made of a conductive material, and the effective length around the parasitic element is approximately one wavelength of the received frequency. There, the relative parasitic element perimeter l, the line width w of the passive element is a value that satisfies the ^{w ≧ 4 · l · e -4.5} , against electromagnetic waves with a frequency the received behind of the antenna An antenna characterized by having an enhancement effect can be obtained.
[0009]
In addition, according to the present invention, there is obtained an antenna characterized in that the parasitic element has an elliptical loop shape including a circle.
[0010]
In addition, according to the present invention, in the antenna, an antenna is obtained in which the parasitic element has a polygonal loop shape.
[0011]
According to the present invention, in any one of the antennas, an antenna can be obtained in which the base is a screen door type antenna constituting a screen door of a building.
[0015]
Further, according to the present invention, in any one of the antennas, as an arrangement interval of the parasitic elements, an interval d between the element centers is l / π ≦ d ≦ 5 · l / An antenna having a value satisfying π can be obtained. Here, in the present invention, the distance between the centers d is limited to the above value, and the value of the above-mentioned diameter to five times the diameter is a value that determines the degree of re-radiation, and other values, l / π> This is because if d or d> 5 · l / π, the re-radiation wave is excessive and the transmitted wave is excessive, and the effect is lost.
[0021]
Further, according to the present invention, in any one of the antennas, the parasitic elements are configured to have the same or a plurality of sizes, and the single or a plurality of frequencies are mixed. An antenna characterized by operation is obtained.
[0022]
According to the present invention, in any one of the antennas, a material having a resistivity ρ ≦ 10 ⁻² (Ω · cm) is used for a conductor used for the parasitic element. An antenna is obtained. Here, in the present invention, when the resistivity ρ exceeds 10 ⁻² (Ω · cm), it is a loss due to re-radiation. As a material thereof, an ordinary metal having high conductivity is used. Any material can be used.
[0023]
Further, according to the present invention, loop-shaped parasitic elements made of a conductive material are provided as an antenna element on a screen door in a lattice shape, and the effective length around the parasitic element is approximately one wavelength of the received frequency. ^Yes, with respect to the parasitic element circumferential length l, the line width w of the antenna element satisfies a value w ≧ 4 · l · e ^−4.5 , and ^enhances the electromagnetic wave having the received frequency behind the antenna A screen door antenna characterized by having an effect can be obtained.
[0024]
Further, according to the present invention, in the screen door antenna, the conductor used for the antenna element is made of a material having a resistivity ρ ≦ 10 ⁻² (Ω · cm). An antenna is obtained. Here, as described above, in the present invention, when the resistivity ρ exceeds 10 ⁻² (Ω · cm), it is a loss for re-radiation. Any metal material having high conductivity may be used.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0026]
(First embodiment)
FIG. 1 is a plan view showing a screen door antenna according to the first embodiment of the present invention, and shows an example of a basic configuration of the screen door antenna of the present invention.
[0027]
Referring to FIG. 1, a screen door antenna 10 is configured by arranging a plurality of loop elements 12 on a screen member 11 which is a base constituting the screen door.
[0028]
FIG. 2 is a diagram schematically showing the arrangement of each element in FIG.
[0029]
As shown in FIG. 2, the centers of the straight line groups of loop-shaped elements 12 intersecting each other at an angle of 60 degrees are aligned with each other, and the distance d between the intersection points is defined as an element interval.
[0030]
The loop-shaped antenna element 12 utilizes both characteristics of a parasitic antenna and a loop antenna whose feeding point is short-circuited. Thus, the parasitic antenna with the feeding point short-circuited re-radiates the received radio wave. At that time, the phase of the re-radiated electric field varies depending on the line thickness and size of the element, and can be in phase with or opposite to the incident wave.
[0031]
Behind the antenna, the transmitted wave of the incident wave and the re-radiated wave are combined, so that if they are out of phase with each other, they are shielded, and if they are in phase, they are enhanced.
[0032]
Since the degree of shielding and enhancement is determined by the balance of the antenna transmitted wave and the antenna re-radiated wave, it depends on the distance between the antenna elements, the line thickness, and the line length, and the characteristics can be adjusted accordingly.
[0033]
Furthermore, in the case of a loop-shaped element in which the feeding point is short-circuited, the characteristic does not have directionality in the loop plane, and thus there is no polarization dependency in the plane.
[0034]
In addition, since the operating frequency is determined by the element size, operation in a plurality of frequency bands is possible by coexisting a plurality of antenna elements having a plurality of sizes.
[0035]
(Second Embodiment)
FIG. 3 is a plan view showing the configuration of a screen door antenna according to the second embodiment of the present invention. As shown in FIG. 3, the antenna 20 has the element spacing d = 100 (mm), the radius r2 = 24 (mm), the width w2 = 0.5 (mm), and every other element group 23. This is an antenna in which an element group 22 having a radius r1 = 55 (mm) and a width w1 = 1.0 (mm) arranged concentrically is formed on a net member 21 forming a base constituting a screen door. This screen type antenna has a parasitic element perimeter length l and the parasitic element has a line width w satisfying w ≦ 4 · l · e ^−4.5 , has a shielding function, and has two frequency bands. It is a shield antenna that operates at
[0036]
FIG. 4 is a diagram showing an antenna measurement system. As shown in FIG. 4, the antenna sample 4 is placed between the transmitting antenna 1 and the receiving antenna 2 that are arranged to face each other, and measurement is performed by a network analyzer connected to each of the transmitting antenna 1 and the receiving antenna 2. In addition, the reference at the time of measurement was taken as the case of transmitting / receiving antenna direct.
[0037]
FIG. 5 is a diagram showing pass characteristics of a shielded antenna according to the second embodiment of the present invention. According to FIG. 5, it can be seen that there are shielding effects at center frequencies of about 800 (MHz) and about 1600 (MHz), respectively, and electromagnetic waves are transmitted in other frequency bands.
[0038]
(Third embodiment)
FIG. 6 is a plan view showing the configuration of a screen door antenna according to the third embodiment of the present invention. As shown in FIG. 6, the screen door antenna 30 has a base that constitutes a screen door with an element group 32 having an element interval d = 62 (mm), a radius r = 12 (mm), and a width w = 6 (mm). This is an antenna formed on the net member 31 to be formed. The screen-type antenna 30 is an enhancement antenna having an enhancement effect in which the line width w of the parasitic element satisfies w ≧ 4 · l · e ^−4.5 with respect to the circumferential length l of the parasitic element.
[0039]
The characteristics of the antenna according to the third embodiment were evaluated in the same manner as that according to the second embodiment using the measurement system shown in FIG. In addition, the reference at the time of measurement was taken as the case of transmitting / receiving antenna direct.
[0040]
FIG. 7 is a diagram showing pass characteristics of a screen door type antenna according to the third embodiment of the present invention. In FIG. 7, the transmission characteristic when there is no sample 4 in FIG. 4 is shown as a reference value (0 dB). According to FIG. 7, an enhancement effect of about 5 (dB) is observed at about 4.3 (GHz). In this case as well, the obtained frequency is the frequency at which the size of the loop-shaped element becomes almost one wavelength, and the antenna can be rotated in the plane by adopting the loop-shaped element, as in the result shown in FIG. It was confirmed that this characteristic did not change.
[0041]
(Fourth embodiment)
FIG. 8 is a plan view showing the structure of a screen door antenna according to the fourth embodiment of the present invention. As shown in FIG. 8, a screen door antenna 40 has an arrangement in which linear elements 41 of about half wavelength are arranged in consideration of arbitrary polarization correspondence in the plane and an effective area of each element, and the base is omitted. Has been. The linear elements are arranged so as to form the sides of an equilateral triangle, and are provided at the apexes so as to be separated from each other.
[0042]
【The invention's effect】
As described above, according to the present invention, an antenna capable of shielding or enhancing an electromagnetic wave of a specific frequency is obtained, and further, an antenna capable of exhibiting characteristics irrespective of the polarization plane of the incoming radio wave is obtained.
[0043]
Moreover, according to this invention, the screen door type antenna provided with the said antenna in the screen doors, such as a building, is obtained.
[0044]
Furthermore, according to the present invention, the characteristics can be adjusted by the distance between the antenna elements, the line thickness, and the line length, and the operation in a plurality of frequency bands is possible by coexisting the antenna elements having a plurality of sizes. A screen door with an antenna is obtained.
[Brief description of the drawings]
FIG. 1 is a plan view showing a basic configuration of an antenna according to a first embodiment of the present invention.
FIG. 2 is a diagram schematically showing the arrangement of each element in FIG. 1;
FIG. 3 is a plan view showing a configuration of an antenna according to a second embodiment of the present invention.
FIG. 4 is a diagram showing an antenna measurement system;
FIG. 5 is a diagram showing pass characteristics of a screen door antenna according to a second embodiment of the present invention.
FIG. 6 is a plan view showing a configuration of a screen door antenna according to a third embodiment of the present invention.
FIG. 7 is a diagram showing pass characteristics of an enhanced antenna according to a third embodiment of the present invention.
FIG. 8 is a plan view showing a configuration of an antenna according to a fourth embodiment of the present invention.
[Explanation of symbols]
1, 2 Transmission / reception antenna 3 Network analyzer 4 Antenna sample 10, 20, 30, 40 Screen door antenna 11, 21, 31 Network member 12, 22, 23, 32 Antenna element 41 Antenna element

Claims (9)

The parasitic element is substantially composed of a base made of a net having at least one loop-shaped parasitic element made of a conductive material, and the effective length around the parasitic element is substantially one wavelength of the frequency to be received. The line width w of the parasitic element is a value satisfying w ≧ 4 · l · e ^−4.5 with respect to the peripheral length l, and has an enhancement effect on the electromagnetic wave having the received frequency behind the antenna. Characteristic antenna. The antenna according to claim 1, wherein the parasitic element has an elliptical loop shape including a circle. The antenna according to claim 1, wherein the parasitic element has a polygonal loop shape. The antenna according to any one of claims 1 to 3, wherein the base is a screen door type antenna constituting a screen door of a building. The antenna according to any one of claims 1 to 4, as an arrangement interval of the passive element, the distance d between the element centers, the element perimeter as l, l / π ≦ d ≦ 5 An antenna having a value satisfying l / π. The antenna according to any one of claims 1 to 5 , wherein the parasitic elements have the same size or a mixture of sizes, and are single or plural. An antenna characterized by operating at a frequency of. The antenna according to any one of claims 1 to 6, wherein the conductor used in the parasitic element, the use of materials such as a resistivity ^{ρ ≦ 10 -2 (Ω · cm} ) Characteristic antenna. On the screen door, loop-shaped parasitic elements made of a conductive material are provided as an antenna element in a lattice shape, and the effective length around the parasitic element is approximately one wavelength of the frequency to be received. to l, the line width w of the antenna element is a value that satisfies the ^{w ≧ 4 · l · e -4.5} , and having an enhanced effect on the electromagnetic waves with a frequency the received behind of the antenna Screen door antenna. 9. The screen door antenna according to claim 8 , wherein a material having a resistivity ρ ≦ 10 ⁻² (Ω · cm) is used for a conductor used for the antenna element.

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