JP3964435B2 - Grid patch antenna - Google Patents

Description

  The present invention belongs to the technical field of a microstrip antenna in a microwave band, which is provided on a window of a building or a vehicle so that the perspective of the external field of view is not blocked as much as possible.

Since the antenna is provided in a window of a building or vehicle, an antenna having a configuration that does not block the field of view as much as possible is required.
Therefore, as a dielectric substrate for providing an electrode, a transparent dielectric material such as glass is used (for example, Patent Document 1), and a transparent conductive film is used as an electrode (for example, Patent Document 2). As an example that is not a transparent electrode, there is one in which fine wire conductors are arranged so as to cross so as to form a mesh (for example, Patent Document 3).

  FIG. 9 shows a base plate 9 in which a large number of non-transparent thin wire conductors are arranged so as to form a square mesh on one side (the back side in the figure) of a transparent dielectric substrate, and the other side ( FIG. 2 is a perspective view of a conventional grid patch antenna in which a similar mesh-like thin wire conductor is provided on the front surface side in FIG.

FIG. 10 is a directivity diagram in which the directivity calculation result of the antenna of FIG. 9 is graphed.
JP 2001-189616 A ([0007], FIG. 1) Japanese Patent Laying-Open No. 2003-17931 ([0010], FIG. 1) Japanese translation of PCT publication No. 2002-511691 ([0025], FIG. 6, [0033], FIG. 7)

  In the above prior art, the transparent conductive film has a problem that the surface resistance value is high and the efficiency as an antenna is low in the microwave band, and when a ground plane or patch is formed by crossing thin wire conductors like a mesh However, there is a problem that the degree to which the field of view is blocked is obstructive when it is provided in a window of a building or a vehicle.

  Therefore, an object of the present invention is to provide a grid patch antenna that does not deteriorate the performance of a conventional grid patch antenna by using a device that does not use a transparent conductive film and does not have a mesh arrangement of thin wire conductors.

In order to solve the above problems, the grid patch antenna of the present invention has the following configurations.
In the first configuration of the present invention, a plurality of fine wire conductors are arranged in parallel on one surface of a transparent dielectric substrate, and both ends thereof are provided in a direction intersecting the parallel direction. A ground plane is formed by short-circuiting with a thin wire-like short conductor, and a plurality of fine wire conductors are arranged side by side in the same direction as the parallel direction on the other surface of the dielectric substrate. A patch is formed by short-circuiting with the fine wire-like short-circuited conductor, and the ground plane side also has a short-circuit conductor that short-circuits the parallel fine-wire conductor in a range corresponding to the short-circuit conductor of the patch, and a feeding point is provided on the patch A thin wire conductor connecting the plurality of parallel thin wire conductors of the patch in the intersecting direction through the feeding point, and a portion on the ground plate facing the thin wire conductor between the plurality of parallel thin wire conductors of the portion. Have thin wire conductors A grid patch antenna according to claim.

  In the second configuration of the present invention, a plurality of fine wire conductors are arranged in parallel on one surface of the transparent dielectric substrate, and both ends thereof are provided in a direction intersecting the parallel direction. A ground plane is formed by being short-circuited by a thin wire-like short conductor, and a plurality of fine wire conductors are arranged side by side in the same direction as the parallel direction on the other surface of the dielectric substrate, and both ends thereof are provided in the intersecting direction. A patch is formed by short-circuiting with the fine wire-like short-circuited conductor, and the ground plane side also has a short-circuit conductor that short-circuits the parallel thin-wire conductor in a range corresponding to the short-circuit conductor of the patch, The dielectric substrate has a feeding point in the middle of any one of the conductors, and the feeding point and the feeding point side cross direction fine wire short-circuit conductor of the patch are parallel to the parallel thin wire conductor of the ground plane. Microstrip on the other side That are connected by road is grid patch antenna according to claim.

  According to a third configuration of the present invention, a ground plate is formed by arranging a plurality of thin wire conductors arranged in parallel on one surface of a transparent dielectric substrate, and the thin wire conductor is formed on the other surface of the dielectric substrate. Are arranged side by side in the parallel direction, and one end of each of them is short-circuited by a thin wire-like short-circuit conductor provided in a direction crossing the parallel direction to form a patch, and the thin wire-like shape of the ground plane It has a thin wire conductor that short-circuits the range corresponding to the short-circuit connection range of the patch in the short-circuit conductor side end portion, and has a feeding point on the short-circuited thin wire conductor, The grid patch antenna is characterized in that the conductor is connected by a microstrip line on the other surface of the dielectric substrate parallel to the parallel thin wire conductor of the ground plane.

In the present invention, when a plurality of linear conductors are arranged on a plane so as to form a mesh, when excited so that one of the intersecting directions becomes the direction of the excitation electric field, Since the conductor in that direction resonates at the excitation frequency, a strong current flows. On the other hand, the current flowing through the intersecting linear conductors is small, but this generates a cross polarization and is unnecessary. However, at least one linear conductor that intersects the minimum necessary excitation direction is necessary to supply an excitation current to an adjacent linear conductor that is parallel to the excitation direction. Therefore, the arrangement is made so as to be symmetric with respect to the Y-direction axis passing through the feeding point so that the radiation from the linear conductor intersecting with the excitation direction cancels each other.
With the above configuration, it becomes possible to eliminate the linear conductors in the crossing direction that contribute to unnecessary radiation as much as possible while securing the linear conductors in the direction of the excitation electric field necessary for the desired radiation. The directivity is practically inferior to some cases.

In the present invention, on the basis of this characteristic, both the ground plane and the patch are basically a plurality of fine wire conductors arranged in parallel to the direction of the excitation electric field.
This means that there are no thin wire conductors in the cross direction except at both ends, and the degree of obstruction that obstructs the field of view is very small as compared to the conventional cross arrangement in which a mesh is formed. The effect of becoming is obtained.

  In the first configuration, the position of approximately one-sixth in the parallel direction of the conductor from the central position of the patch is a position that matches 50Ω, and therefore it is best to provide the feeding point at this position.

  In the second configuration, since the impedance at the patch end is high, it is best to provide a quarter-wave transformer in the middle of the feeding microstrip line to match 50Ω.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view of an embodiment of the first configuration in the present invention. The thin wire conductors arranged in parallel in the horizontal direction (this is the Y direction) at equal intervals on the lower surface side of the transparent dielectric substrate 1, and the ends of each thin wire conductor are short-circuited to both ends thereof. In this way, the ground plane 3 is formed which is composed of a thin wire conductor in the intersecting direction (vertical direction, which is the X direction).
On the upper surface of the transparent dielectric substrate 1, a patch 2 having vertical and horizontal dimensions smaller than that of the ground plane 3 is formed. The patch 2 also includes a plurality of horizontal thin wire conductors arranged in parallel at equal intervals, and both side ends thereof are short-circuited by thin wire conductors in an intersecting direction (X direction) that short-circuit each end.

And the connection conductor of the partial crossing direction is provided also on the ground plane corresponding to the short circuit connection conductor of this patch. The feeding point 4 is provided at a position approximately one-sixth of the lateral length of the patch from the center position of the patch 2. In the figure, power is supplied to the middle conductor of the seven thin wire conductors in the horizontal direction.
Then, thin wire conductors that connect the seven lateral conductors are provided in the crossing direction (X direction) through the feeding point 4, and seven conductors on the ground plate 3 side with the transparent dielectric substrate 1 interposed therebetween. A thin line-shaped conductor for connecting the horizontal conductors is provided.

FIG. 2 is a directivity diagram by calculation of the antenna of FIG.
Compared with the directivity diagram (FIG. 10) of the antenna (FIG. 9) in which the conventional thin wire conductors are arranged in a mesh shape, the level in the back direction (180 degree direction) is rather small. It is about.

FIG. 3 is a perspective view of an embodiment of the second configuration in the present invention.
The difference from the configuration of FIG. 1 is that the position of the feeding point is different. In FIG. 1, it is provided in the patch 2, but in FIG. 3, it is located at the center position on the short-circuit conductor in the X direction on the left side of the ground plane 6, and the external conductor side of the feeder line (for example, coaxial cable) not shown is the ground plane 6. The center conductor side passes through the hole provided in the transparent dielectric substrate 1 and appears on the patch surface side, and the microstrip line running in the Y direction from that position is matched with 50Ω. Are connected to the left X-direction conductor of the patch 5 through a one-wavelength transformer.

FIG. 4 is a directivity diagram by calculation of the antenna of FIG.
Due to the radiation from the microstrip line for feeding power to the patch 5 and the quarter-wave transformer, the E-plane main polarization directivity becomes asymmetrical with less drop on the back side. The directivity characteristics close to the directivity characteristics are shown.

FIG. 5 is a perspective view of an embodiment of the third configuration in the present invention.
The difference from the configuration of FIG. 3 is that the ground plane 8 is different from the ground plane 6 of FIG. The base plate 8 is not provided with the right X-direction conductor, and is not provided over all the parallel conductors on the left side, but only in a range corresponding to the X-direction width of the patch 12. Furthermore, X-direction conductors corresponding to the X-directions at the left and right ends of the patch 12 are not provided.
Also, the patch 12 does not have a right X-direction short-circuit conductor. The method of supplying power to the patch 12 is the same as the configuration of FIG.

FIG. 6 is a directivity diagram by calculation of the antenna of FIG.
As in FIG. 4, in the E-plane main polarization directivity, the dip on the back side is smaller than that in FIG. 10, but on the front side is not much different from that in FIG. 10.
As described above, in the grid patch antenna of the present invention, both the ground plane and the patch are arranged with a large number of thin wire conductors in parallel, and the short-circuit connection conductors in the cross direction (X direction) are provided or not provided on the left and right ends thereof. Alternatively, it is provided in a part of the range, and is not a mesh-like configuration as in the conventional FIG. 9, but such a configuration also has a mesh structure as described below in the reflection loss characteristic and the transmission loss characteristic. Is not inferior to

FIG. 7 is a diagram showing reflection loss characteristics and transmission loss characteristics with respect to incident radio waves in the case where a large number of thin line conductors are vertically and horizontally crossed to form a mesh.
(A) is a diagram showing a mesh arrangement configuration, (b) is a loss of the ratio of reflection and non-transmission when radio waves (2.45 GHz) are incident on a plane where the configuration of (a) continues indefinitely And the result is graphed.
The calculation is performed under the condition of increasing the mesh interval while maintaining the relationship between the line width of the fine wire conductor and the mesh interval in (a) so that the light transmittance is kept constant at 95%. The reflection loss and transmission loss for each mesh interval were calculated.
(B) is a graph of both losses with the mesh interval as the horizontal axis.

As an antenna, it is preferable that the amount of reflection with respect to incident radio waves is small and the amount of transmission is small (in other words, the transmission loss is large). This means that as much incident radio waves as possible should be input to the receiver.
Speaking this in line with FIG. 7B, the smaller the reflection loss (lower) and the larger the transmission loss (upward), the better.

  When the mesh interval is 1 mm, the reflection loss is −15.6 dB and the transmission loss is −0.11 dB. However, as the mesh interval increases, the reflection loss increases (increases) and the transmission loss decreases. When the mesh interval is 10 mm, the reflection loss is -10 dB and the transmission loss is -0.51 dB.

On the other hand, FIG. 8 is a diagram showing the reflection loss characteristic and the transmission loss characteristic with respect to the incident radio wave when the thin wire conductors are arranged infinitely in parallel.
(A) is a figure which shows the parallel arrangement | positioning of a thin wire | line conductor, (b) is the same as the case of FIG. 7, and calculates the case where a radio wave injects into the plane where the arrangement shown in (a) continues infinitely. It is a thing. That is, the relationship between the line width and the interval is such that the line width is changed so that the light transmittance is kept constant at 95%, and the set frequency is 2.45 GHz.

As shown in FIG. 8B, when the interval is 1 mm, the reflection loss is −16.4 dB and the transmission loss is −0.1 dB. Compared with FIG. 7B, the reflection loss is small and the transmission loss is large. It is a more preferable numerical value.
Further, in the case where the interval is 10 mm, in FIG. 7B of the mesh arrangement, the reflection loss is −10 dB and the transmission loss is −0.51 dB as described above, whereas the parallel arrangement is In FIG. 8B, the parallel loss is much more preferable because the reflection loss is -16.4 dB and the transmission loss is -0.1 dB, as in the case of the interval of 1 mm. 7 (b) and FIG. 8 (b) are compared, FIG. 7 (b) shows only the case where the mesh interval is up to 10 mm, but even in the range exceeding 10 mm, It is apparent that the parallel arrangement in FIG. 8 is more preferable as an antenna than the mesh (intersection) arrangement in FIG.

  As described above, the antenna of the present invention maintains the directivity characteristics almost the same as those of the conventional mesh array antenna, and obtains excellent characteristics in the incident loss characteristics and the transmission loss characteristics, while maintaining the cross direction conductors. Since it is configured not to be used, there is an advantage that when it is arranged in a window of a building or a vehicle, it is less obstructive than a conventional mesh type.

It is a perspective view of the Example of the 1st structure of this invention. It is a directivity figure by calculation of the antenna of FIG. It is a perspective view of the Example of the 2nd structure of this invention. FIG. 4 is a calculated directivity diagram of the antenna of FIG. 3. It is a perspective view of the Example of the 3rd structure of this invention. FIG. 6 is a calculated directivity diagram of the antenna of FIG. 5. It is a figure which shows the reflection loss characteristic and transmission loss characteristic with respect to an incident electromagnetic wave at the time of arrange | positioning so that many fine wire conductors may cross | intersect a length and breadth and it may form a mesh | network infinitely. It is a figure which shows the reflection loss characteristic and transmission loss characteristic with respect to an incident radio wave when a thin wire | line conductor is arrange | positioned infinitely in parallel. A ground plate is formed by crossing a large number of non-transparent thin wire conductors so that a square mesh can be formed on one surface of a transparent dielectric substrate, and a similar mesh-like thin wire conductor is provided on the other surface. It is a perspective view of the conventional grid patch antenna which used this as a patch. FIG. 10 is a directivity diagram in which the antenna directivity calculation result of FIG. 9 is graphed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent dielectric substrate 2 Patch 3 Ground plane 4 Feeding point 5 Patch 6 Ground plane 7 Feeding point 8 Ground plane 9 Ground plane 10 Patch 11 Microstrip line 12 Patch

Claims (3)

  A plurality of fine wire conductors are arranged in parallel on one surface of the transparent dielectric substrate, and both ends of each are short-circuited by thin wire short-circuit conductors provided in a direction crossing the parallel direction. A ground plane is formed, and on the other surface of the dielectric substrate, a plurality of fine wire conductors are arranged side by side in the same direction as the parallel direction, and both ends thereof are short-circuited by thin wire short conductors provided in the intersecting direction. A patch is formed, the ground plane side also has a short-circuit conductor that short-circuits a parallel thin wire conductor in a range corresponding to the short-circuit conductor of the patch, has a feeding point on the patch, passes through the feeding point, and crosses A thin wire conductor that connects between a plurality of parallel thin wire conductors of the patch in a direction, and a thin wire conductor that connects between the plurality of parallel thin wire conductors of the portion on a portion of the ground plate facing the thin wire conductor. Grid pad Chiantena.   A plurality of fine wire conductors are arranged in parallel on one surface of the transparent dielectric substrate, and both ends of each are short-circuited by thin wire short-circuit conductors provided in a direction crossing the parallel direction. A ground plane is formed, and on the other surface of the dielectric substrate, a plurality of fine wire conductors are arranged side by side in the same direction as the parallel direction, and both ends thereof are short-circuited by thin wire short conductors provided in the intersecting direction. A patch is formed, and the ground plane side also has a short-circuit conductor that short-circuits the parallel thin wire conductor in a range corresponding to the short-circuit conductor of the patch, A microstrip line on the other surface of the dielectric substrate that has a feeding point and the feeding point side crossing direction fine wire short-circuit conductor of the patch is parallel to the parallel thin wire conductor of the ground plane Connected Grid patch antenna according to claim. A ground plane is formed by arranging a plurality of fine wire conductors arranged in parallel on one surface of the transparent dielectric substrate, and a plurality of fine wire conductors arranged in the parallel direction on the other surface of the dielectric substrate. A patch is formed by short-circuiting each of one end of each of them arranged with a thin wire-like short-circuit conductor provided in a direction crossing the parallel direction, and the patch of the fine-wire short-circuit conductor side end portion of the ground plane is formed. A thin wire conductor that short-circuits a range corresponding to the short-circuit connection range, a feeding point on the short-circuited thin wire conductor, and the feeding point and the cross-direction thin wire-like shorting conductor of the patch A grid patch antenna, which is connected by a microstrip line on the other surface of the dielectric substrate parallel to the conductor.

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