JP2002084127A - Antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an element antenna, having optimal characteristics with prescribed frequencies capable of correcting the resonance frequencies. SOLUTION: A dielectric is made of stretchable materials, and an element antenna is constituted of a mesh-shaped conductor, so that the size of the element antenna corresponding to desired frequencies can be acquired, and a uniform tension is applied to each side of the dielectric so that the dimension of the element antenna can be changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device for transmitting and receiving high frequency signals in a microwave band and a millimeter wave band.

[0002]

2. Description of the Related Art An antenna device using a microstrip antenna disclosed in the following document as an element antenna is well known. "New Antenna Engineering", published by Ohmsha, Naohisa Goto, pp115-123 (1986)

One example showing the configuration of a conventional antenna device is as follows.
This will be described with reference to the drawings. FIG. 7 is a perspective view of the antenna device, and FIG. 8 is a sectional view. In the figures, the same numbers as those in the other figures are the same. In the figure, 1 is a dielectric substrate, 2 is an element antenna disposed on the upper surface of the dielectric substrate 1, 3 is a ground conductor disposed on the lower surface of the dielectric substrate 1, and 4 is a connector. The dielectric substrate 1 has a thin conductor plate adhered to both sides, and the element antenna 2 is formed by etching one of the thin conductor plates of the dielectric substrate 1. Earth conductor 3
Uses a thin conductor plate on the opposite side of the element antenna 2. The center conductor of the connector 4 is connected to a point shifted from the center of the element antenna 2 from below the ground conductor 3, and the outer conductor of the connector 4 is connected to the ground conductor 3.

Next, the operation will be described. The antenna is
Since transmission and reception are reversible, the case where the antenna is transmitting will be described. The signal supplied from the connector 4 is
Is supplied to the element antenna 2 through the center conductor of the antenna, the element antenna 2 is excited at a frequency described below, and a radio wave is radiated to operate as an antenna.

The frequency to be excited is the frequency fr (Hz) at which the element antenna 2 resonates.
A frequency fr (Hz) determined by a dimension a, a thickness t of the dielectric substrate 1, and a relative permittivity εr of the dielectric substrate 1,
Equations (1), (2) and (3) show. Here, c is the speed of light, εe is the effective permittivity, and Δa is the correction value of the line expansion of the element antenna 2 having the dimension a shown in FIG. 7 due to fringing.

[0006]

(Equation 1)

[0007]

(Equation 2)

[0008]

(Equation 3)

[0009]

In the conventional antenna device as described above, the resonance frequency is uniquely determined by the dimensions of the element antenna, the thickness of the dielectric substrate, and the relative permittivity. There was a problem that it was not possible to adjust the error.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to correct fluctuations in the resonance frequency and optimize the characteristics of the antenna device at a desired frequency.

[0011]

According to a first aspect of the present invention, there is provided an antenna device comprising: a dielectric which can be expanded and contracted by a tension in a direction in which a first dielectric and a second dielectric are stretched; It is configured by arranging conductor wires in a mesh shape.

An antenna device according to a second aspect of the present invention is an antenna device in which the element antennas are arranged in an array.

An antenna device according to a third aspect of the invention is configured so that the curvature of the antenna device can be changed by applying pressure from below the second dielectric and increasing or decreasing the pressure.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 An example of the configuration of the antenna device according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of the antenna device, and FIG.
FIG. 2 is a sectional view taken along line AA in FIG. In the figures, the same numbers as those in the other figures are the same. In the figure, reference numeral 5 denotes a stretchable first dielectric, for example, rubber, which expands when tension is applied, and returns when tension is not applied. Reference numeral 6 denotes an element antenna in which conductor wires are arranged in a mesh on the upper surface of the first dielectric 5. The mesh-shaped conductor is a first antenna so as to follow expansion and contraction of the first dielectric 5. Is bonded to the dielectric 5. Reference numeral 7 denotes an extendable second dielectric, 8 denotes a ground conductor in which conductor wires are arranged in a mesh on the entire lower surface of the second dielectric 7, and the mesh-shaped conductor is Is adhered to the second dielectric 7 so as to be able to follow the expansion and contraction of. 9 is the first dielectric 5
And a spacer for keeping the distance between the first dielectric 5 and the second dielectric 7 constant. The spacer is disposed at an appropriate position so as to keep the distance between the first dielectric 5 and the second dielectric 7 constant. Reference numeral 10 denotes a rotatable take-up shaft fixed to an external housing to which the antenna device is fixed, to which an end of the first dielectric 5 or the second dielectric 7 is connected, Are arranged as much as possible at the four corners of the dielectric 5 and the second dielectric 7 is similarly arranged. Reference numeral 4 denotes a connector. The inner conductor of the connector 4 is connected to the element antenna 6, and the outer conductor is connected to the ground conductor 8.

The dimensions of the element antenna 6 are such that tensions F1, F2, F3 and F4 are applied to the respective sides of the first dielectric 5 and the second dielectric 7 in the directions of the arrows shown in FIG. In this state, the configuration is such that dimensions a and b shown in FIG. 1 are obtained.

Next, the operation will be described with reference to FIGS. 1 and 2. FIG. Since the antenna is reciprocal for transmission and reception, a case where the antenna is for transmission will be described. The signal fed from the connector 4 is fed to the element antenna 6 through the center conductor of the connector 4, and the element antenna 6 is excited by the signal, emits a radio wave and operates as an antenna.

The frequency at which the element antenna 6 emits radio waves will be described. The element antenna 6 has a dimension a in FIG.
And a second dielectric material including a spacer 9 from the upper surface of the first dielectric 5.
The thickness t in FIG. 2 showing up to the lower surface of the dielectric 7 and the second dielectric 7 including the spacer 9 from the upper surface of the first dielectric 5.
Is obtained from the equivalent dielectric constant up to the lower surface of the first dielectric 5, where the thickness of the first dielectric 5 and the second dielectric 7 is very thin with respect to the thickness t and can be ignored. Spacer 9 from top
Considering the equivalent dielectric constant up to the lower surface of the second dielectric 7 including the relative dielectric constant of air, the dimension b in FIG.
Assuming the same as Equations (1), (2), and (3) shown in the prior art
Radio waves can be radiated at the resonance frequency fr (Hz) that is more determined.

Also, by rotating the rotating shaft 10 connected to the first dielectric 5 in the direction in which the first dielectric 5 is wound up as shown by the rotation arrows in FIGS. 1
F1, F2, F3 in the direction of the arrow shown in FIG.
A state can be formed in which the tensions F4 and F4 are applied, and the dimensions a and b shown in FIG. 1 of the element antenna 6 can be set to the dimensions described above, and the same applies to the second dielectric 7.

Next, the elongation α when the tension F is applied to the first dielectric 5 and the second dielectric 7 having a sectional area of S is:
It can be obtained from the Young's modulus ε of the first dielectric 5 and the second dielectric 7 and can be obtained by Expression 4.

[0020]

(Equation 4)

Therefore, the tensions F1 to F4 are changed to F1 'to F4'.
, The dimensions a and b of the element antenna 6 become the dimensions a ′ and b ′ as shown in Expressions 5 and 6.

[0022]

(Equation 5)

[0023]

(Equation 6)

At this time, the resonance frequency fr 'is given by
The resonance frequency can be changed by a change in the tension, which is obtained from Equation 3, and when the resonance frequency deviates from a desired value due to a manufacturing error or the like, the resonance frequency is adjusted by adjusting the tension. Can be.

Embodiment 2 An example of the configuration of the antenna device according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 3 is a perspective view of the antenna device, and FIG. 4 is a cross-sectional view taken along a line BB in FIG. In the figures, the same numbers as those in the other figures are the same. The antenna device according to the second embodiment differs from the antenna device according to the first embodiment in a state where tensions F1, F2, F3, and F4 are applied.
Are arranged in an array at intervals of an element interval d (mm).

The element spacing d (mm) is determined by Equation 7 based on the wavelength λ (mm) and the beam scanning angle Θ (deg) because no grating lobe is generated.

[0027]

(Equation 7)

In the same opening, the number of elements increases in inverse proportion to the element spacing d (mm). Therefore, the element spacing d (mm) is usually the maximum element spacing d (mm) in the absence of grating lobes. ) Is selected.

Here, the resonance frequency f of the element antenna 6 is changed by changing the tensions F1, F2, F3 and F4.
As described in the first embodiment, it is possible to change r (Hz). However, by converting this into an array, the resonance frequency fr (Hz) and the element interval d (m) can be changed.
Since m) also changes, a beam can be formed without lowering the radiation efficiency of the element antenna 6.

Embodiment 3 An example of the configuration of the antenna device according to Embodiment 3 of the present invention will be described with reference to the drawings. FIG. 5 is a perspective view of the antenna device, and FIG. 6 is a cross-sectional view taken along line CC in FIG. In the figures, the same numbers as those in the other figures are the same. In the antenna device according to the second embodiment, the dimensions a and b of the element antenna 6 in FIG. 3 are applied to each side of the first dielectric 5 and the second dielectric 7.
, The tension is applied from the lower side of the second dielectric 7 while the tension of F1, F2, F3, F3 is applied, so that the first dielectric 5 and the second Dielectric 7
Then, a pressure of F5 indicated by an arrow in FIGS. 5 and 6 is applied from below the second dielectric 7 so that the first dielectric 5 and the second dielectric 7 have an arbitrary curvature. In the bent state, the dimensions a and b of the element antenna 6 shown in FIG. 5 are determined by the equations 1, 2, and 3 shown in the conventional example, and the element spacing d (mm) is set to a desired value. Configure to be an array pattern. Here, the first dielectric 5 and the second dielectric 7 are held by spacers 9, and the interval t shown in FIG. 5 is held constant.

Next, the operation will be described with reference to FIGS. 5 and 6. FIG. The radiation operation as an antenna and the operation by changing the tension are the same as those in the first embodiment. Similarly to the second embodiment, by changing the phase of the signal input to the connector 4 so that the phases of the radio waves radiated from the respective element antennas 6 are aligned in an arbitrary direction, the array pattern is formed. Perform beam scanning.

Here, when beam scanning is performed to a wider angle, the first dielectric 5 and the second dielectric 5 are increased by increasing the pressure F5 applied from below the second dielectric 7. By increasing the curvature of 7, the beam scanning range increases by the amount of the increased curvature. In addition, the frequency to be used is changed by increasing the pressure F5.
In the dimensions a and b, the frequency is changed to a frequency having an optimum characteristic.

[0033]

According to the first aspect of the invention, the dielectric is made of a stretchable material, the element antenna is formed of a mesh-shaped conductor wire, tension is applied to pull the dielectric, and the tension is adjusted. Thus, since the dimensions of the element antenna can be changed, the resonance frequency can be corrected, and an element antenna having optimum characteristics at a desired frequency can be obtained.

According to the second aspect of the present invention, the dielectric is made of a stretchable material, the element antenna is formed of a mesh-shaped conductor, and tension is applied to pull the dielectric, and the tension is adjusted. Accordingly, since the dimensions and the element spacing of the element antenna can be changed, the element spacing changes with the change of the resonance frequency, so that there is an effect that the beam can be formed without lowering the radiation efficiency.

According to the third aspect of the present invention, the dielectric is made of a stretchable material, the element antenna is formed of a mesh-shaped conductor, and pressure is applied from below the dielectric to reduce or increase the pressure. By changing the curvature of the antenna device, by changing the curvature of the antenna device,
There is an effect that the beam scanning angle can be widened.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of the antenna device according to the first embodiment of the present invention.

FIG. 3 is a perspective view of an antenna device according to a second embodiment of the present invention.

FIG. 4 is a sectional view of an antenna device according to a second embodiment of the present invention.

FIG. 5 is a perspective view of an antenna device according to a third embodiment of the present invention.

FIG. 6 is a sectional view of an antenna device according to a third embodiment of the present invention.

FIG. 7 is a perspective view showing a conventional antenna device.

FIG. 8 is a sectional view showing a conventional antenna device.

[Explanation of symbols]

Reference Signs List 1 dielectric substrate, 2 element antenna, 3 ground conductor, 4 connector, 5th dielectric, 6 element antenna, 7 second dielectric, 8 ground conductor, 9 spacer, 10 rotation axis.

Continued on the front page F-term (reference) 5J021 AA05 AA06 AA11 AB06 DB03 GA02 5J045 AA00 BA01 DA09 EA07 FA02 LA01 LA03 5J046 AA04 AB13 PA07 PA10

Claims (3)

[Claims] 1. A first dielectric, an element antenna disposed on an upper surface of the first dielectric, and a second antenna disposed in parallel with a spacer below the first dielectric via a spacer. A dielectric, a ground conductor disposed on the lower surface of the second dielectric, and a lower conductor disposed on the lower surface of the ground conductor, connecting an outer conductor to the ground conductor;
An antenna device having a connector for connecting a center conductor to the element antenna, wherein the first and second dielectrics are made of a dielectric which can be expanded and contracted by a tension in a direction in which the first and second dielectrics are stretched, and the element antenna and the ground conductor are connected to each other. An antenna device, wherein conductor wires are arranged in a mesh shape. 2. The antenna device according to claim 1, wherein said element antennas are arranged in an array. 3. The antenna device according to claim 1, wherein a pressure is applied from a lower part of the second dielectric.