JPH01316007A - Microstrip patch antenna - Google Patents

Abstract

PURPOSE:To make the characteristic of the directivity of a patch antenna on a horizontal plane omnidirectional by constituting the radiation element of an open planar circuit with a patch of a patch antenna, applying transmission/reception of an ultrashort wave or a microwave band electromagnetic wave with the patch and connecting at least part of the outer circumference of the patch to the ground line. CONSTITUTION:A prescribed range of a patch 4 is connected to a short-circuit conductor 8 as a bonding part 4b, the short-circuit conductor 8 is connected to the ground plate 3 and the bonding range of the bonding part 4b with respect to the short-circuit conductor 8 is set by a center angle theta. The short-circuit conductor 8 is formed with a shape of cylinder side face through the setting and both side faces are subject to micro bonding to the surface of the ground plate 3 and the patch 4b respectively by bonding or the like and the directivity of the patch antenna 1 is made omnidirectional on the horizontal plane. Then the patch 4 acts like a planar microwave circuit by the antenna 1 and a high frequency signal sent from the transmitter-receiver via the feeder 6 at the transmission is radiated from the patch 4 and the signal received by the patch 4 at the reception is sent to the transmitter-receiver via the feeder 6 at the reception.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a small, eaves-heavy printed antenna, and particularly to a microstrip patch antenna suitable for mobile communications.

[Prior Art] In recent years, there has been remarkable progress in reducing the size and weight of antenna devices, and various microstrip antennas for very high frequency bands or extremely high frequency bands have been constructed by forming radiating elements on printed circuit boards. Among these microstrip antennas, a microstrip patch antenna (hereinafter simply referred to as a patch antenna) that uses an open planar circuit resonant element made of a circular, rectangular, etc. flat conductor as a radiating element is attracting attention. This is equipped with a flat conductor grounding plate provided on the back side of a flat dielectric printed circuit board, and a round, square, etc. flat conductor patch formed on the surface by printing technology such as etching, and the power supply line is connected to this patch. At the same time, a grounding wire is connected to the grounding plate. The radiation directivity characteristic of this patch antenna is that the plane of the printed circuit board is
It has a unidirectional directivity pattern with the maximum directivity coefficient in the Z-axis direction (namely, the zenith direction).

On the other hand, as a power feeding method for the patch antenna, a technique has been proposed in which the patch 40 and the ground plate 30 are connected using a plurality of short pins 50, as shown in FIG. According to this, the directivity pattern is axially symmetrical in the horizontal plane with respect to the Z-axis, and is said to be suitable for a mobile communication antenna.

Further, Japanese Patent Publication No. 60-40203 discloses a microstrip antenna in which the center of the plate surface of a radiation conductor element and a ground conductor are short-circuited and a plurality of feeding points are provided to the radiation conductor element.

[Problems to be Solved by the Invention] In the microstrip antenna described in the above publication, the radiating element is shaped into an ellipse, and the feeding point and the short-circuit point are specified at predetermined positions, thereby providing two input and output terminals that resonate at different frequencies. However, there is only one short-circuit point, and there is no particular mention of directivity.

In mobile communication such as a car telephone, the direction of transmission and reception is not fixed, so it is desirable to be able to always perform transmission and reception with a stable gain regardless of the direction of movement of the mobile body such as a car. As a countermeasure to this problem, it is necessary to improve the transmitter/receiver device, but it is important to make the antenna's directivity characteristic omnidirectional in the horizontal plane.

According to the above-mentioned conventional technology, it is said that omnidirectionality in the horizontal plane (horizontal omnidirectionality) can be achieved by connecting the patch and the ground plate with a short pin in a patch antenna. The location and suitability for mounting on mobile objects are issues to be addressed in the future. Furthermore, even if it is effective to provide a short pin, there are many problems that need to be solved when manufacturing a patch antenna, such as identifying the installation position and how to install it.

Therefore, an object of the present invention is to obtain omnidirectional directivity in the horizontal plane with a simple structure in a patch antenna.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a grounding plate made of a flat plate conductor, and a flat plate arranged parallel to the plate surface with a predetermined gap within the outer periphery of the grounding plate. In a microstrip patch antenna comprising a patch made of a conductor, a feed line connected to the patch, and a ground wire connected to the ground plate, at least a part of the outer periphery of the patch is electrically connected to the ground plate. This is what I did.

Preferably, a ground plate made of a flat conductor, a circular patch made of a disc conductor arranged parallel to the plate surface with a predetermined gap within the outer periphery of the ground plate, and a power supply connected to the circular patch. In a microstrip patch antenna comprising an electric wire and a ground wire connected to the ground plate, the feed line is connected to a feed point offset from the center of the plate surface of the circular patch, and the feed line is connected to the feed point of the circular patch passing through the feed point. At least a portion within a predetermined range of the outer periphery of the circular patch including the intersection of the radius and the outer periphery of the circular patch is electrically connected to the ground plate.

Further, at least a part of the outer periphery of the circular patch, which is within a range of 45° at a central angle of the circular patch, including the intersection of the radius passing through the power feeding point and the outer periphery of the circular patch, is electrically connected to the ground plate. It's good to do that.

Furthermore, it is preferable that the entire outer peripheral edge of the circular patch within a center angle of 45 degrees is electrically connected to the ground plate.

A preferred embodiment of the present invention includes a grounding plate made of a flat conductor, a patch made of the flat conductor arranged parallel to the plate surface with a predetermined gap within the outer periphery of the grounding plate, and a feeder line connected to the patch. and a grounding wire connected to the grounding plate, at least a part of the outer periphery of the patch at a symmetrical position with respect to the center of the plate surface of the patch is conductively connected to the grounding plate. It is preferable that a pair of short-circuit conductors be provided, and a feed point of the feed line be provided between each of the pair of short-circuit conductors and the center of the plate surface of the patch.

Further, another pair of short-circuiting conductors is provided on an outer peripheral edge of the patch on an axis that includes the center of the plate surface of the patch and is substantially orthogonal to an axis connecting the pair of short-circuiting conductors, and the other pair of short-circuiting conductors A feeding point of the feeding line may also be provided between each of the patches and the center of the plate surface of the patch.

[Operation] In the patch antenna configured as described above, the patch constitutes a radiating element of an open planar circuit, and this patch transmits and receives electromagnetic waves (radio waves) in the very high frequency band or extremely high frequency band. Transmission and reception signals are transmitted via the connected power supply line. Since at least a portion of the outer periphery of the patch is connected to the ground plate, the patch antenna exhibits omnidirectionality in the horizontal plane.

[Embodiment] Hereinafter, preferred embodiments of the four-piece antenna of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross section of a patch antenna 1 according to an embodiment of the present invention, in which a grounding plate 3 made of a copper plate or copper foil, which is a flat conductor, is bonded to the back surface of a dielectric substrate 2. A through hole 2a is provided approximately in the center of the substrate 2 and the ground plate 3, respectively.
and 3a are bored so that both are polymerized. A ground wire 5 of the cylindrical outer conductor of the coaxial line 7 is connected to the through hole 3 a of the ground plate 3 .

A circular patch 4 made of a circular conductor (copper plate or copper foil) is formed on the substrate 2 so as to cover the through hole 2a. This patch 4 is formed on the substrate 2 by etching, but other printing techniques (for example additive methods) may also be used. Therefore, the patch 4 is connected to the ground plate 3
They are parallel to each other and are arranged with a predetermined gap equal to the thickness of the substrate 2. And the patch 4 is compared to the ground plate 3/
11 area, and at a position offset by a predetermined distance from the center 4C of the plate surface, the feeder line 6 at the center of the coaxial line 7 is connected by micro-joining such as adhesive to form a feeder point 4a. This power supply line 6 is inserted through the through holes 2a and 3a and housed in the cylinder of the ground line 5. That is, a coaxial line 7 consisting of a grounding line 5 and a power supply line 6
One end is joined to the patch antenna 1, a grounding line 5 is grounded at the other end, and a feed line 6 is connected to a transmitting/receiving device (not shown).

A predetermined range of the outer periphery of the patch 4 serves as a joint 4b and is connected to a shorting conductor 8, which in turn is connected to the grounding plate 3. The joint range of the joint portion 4b with the short-circuit conductor 8 is set at a central angle θ as shown in FIG.
is set to .

Therefore, the shorting conductor 8 is formed of a conductor formed in the shape of a cylindrical side surface, and both end surfaces thereof are micro-bonded to the surface of the ground plate 3 and the joint portion 4b of the patch 4 by adhesive or the like.

According to the patch antenna 1 configured as described above, the patch 4 functions as a resonant element of an open planar circuit, and the patch 4 constitutes a radiating element. Therefore, during transmission, a high frequency signal transmitted from the transmitting/receiving device via the feed line 6 is radiated from the patch 4 as a very high frequency wave or extremely high frequency wave, and during reception, the signal received by the patch 4 is transmitted to the feed line 6.
is transmitted to the transmitting/receiving device via. In this case,
Since the joint 4b at the outer periphery of the patch 4 is connected to the ground plate 3 via the short-circuit conductor 8, the directivity of the patch antenna 1 exhibits omnidirectionality in the horizontal plane. Therefore, even when the patch antenna 1 is mounted on a mobile object whose direction of movement changes, stable transmission and reception can be performed regardless of the direction of movement.

In order to confirm the above effect, the inventor of the present invention conducted the following test. That is, the patch antenna 11 shown in FIG. 3 was formed with the same configuration as the patch antenna 1 except for the substrate 2 shown in FIG. It was measured.

As a result, in the y-axis-Z-axis plane in Figure 3, the directivity pattern becomes like the field pattern in Figure 5,
Two lobes are formed whose maximum radiation direction is shifted horizontally. The directivity pattern in the X-axis-y-axis plane in FIG. 3 is like the field pattern in FIG. 6, indicating omnidirectionality. These are directional characteristics suitable for mobile communication, such as car telephones.

In both FIGS. 5 and 6, the radial direction is shown on a logarithmic scale.

For example, as shown in FIG.
If the antenna 0 is made of plastic and the patch antenna 11 is buried therein, stable calls can be made using a car phone, citizen band transmission and reception, etc., without damaging the appearance of the car due to the antenna.

As described above, the patch antenna 1 in the above embodiment can achieve the intended purpose regarding directivity characteristics with a simple structure in which the outer peripheral edge of the patch 4 is connected to the ground plate 3 within a predetermined range. Therefore, when manufacturing the patch antenna 1, it is possible to set a predetermined range by specifying the angle θ (45° in this example) from the center of the specific part of the outer periphery of the patch 4. is easy and can be mass-produced.

Furthermore, even when mounted on a car, the patch 4 and the grounding plate 3 can be firmly connected by the shorting conductor 8, so the board 2
It is also possible to directly embed it in the roof as shown in FIG. 3 with the structure removed. Note that instead of the short-circuit conductor 8 of the patch antenna 1, a plurality of (for example, five) connection lines may be arranged in parallel in a predetermined range of the outer periphery of the patch 4.

7 and 8 relate to other embodiments of the patch antenna of the present invention, in which the patch antenna 21 does not include a substrate, compared to the embodiments shown in FIGS. As shown in the figure, a grounding plate 23 and a patch 24 are disposed facing each other with air, which is an electrical element, interposed therebetween. Of course, as in the embodiments shown in FIGS. 1 and 2, a ground plate 23 made of a copper plate serving as a flat conductor is bonded to a dielectric substrate such as a honeycomb board or a polytetrafluoroethylene resin, and a patch 24 is formed on the dielectric substrate. You can also do it.

In this embodiment, the patch 24 is, for example, a circular patch made of a copper disc conductor, and a pair of short-circuit conductors 28a, 28b are connected to joints 24a, 24b of a part of the outer periphery symmetrically with respect to the center 24C of the plate surface. are connected to each other. At this time, the bonding range between the bonding portion 24a and the short-circuit conductor 28a, and the bonding portion 24. b and the short-circuit conductor 28b are set at the central angle θ1°θ2 in FIG.
° is set. width of shorting conductors 28a and 28b;
That is, the lengths of the patches 24 in the direction perpendicular to the plate surface are equal, so when they are joined to the ground plate 23, the patch 24 and the ground plate 23 face each other with a predetermined gap of the above width, and the two are short-circuited. They are electrically connected via conductors 28a and 28b.

Then, as shown in FIG. 8, the center 24 of the plate surface of the patch 24
on the axis that connects the midpoint of each of the joint parts 24a and 24b, and so that the feeding points 24d and 24e are located on both sides of the center 24c of the plate surface, that is, the short-circuit conductors 28a and 28b
The feeder lines 26a, 2 are positioned so as to be shifted a predetermined distance to the
6b is joined. These power supply lines 26a and 26b pass through through holes drilled in the ground plate 23, as shown in FIG. 7, and are connected to the ground line 25a.

They are housed in the respective cylinders of 25b, forming a coaxial line. These feeder lines 26a, 26b are connected together to a transmitting/receiving device (not shown) and conductive to each other, and the grounding lines 25a, 2
5b is commonly grounded.

Thus, a high frequency signal transmitted from the transmitting/receiving device via the feed lines 26a, 26b is radiated from the patch 24, which is a radiating element, as a very high frequency wave or an extremely high frequency wave, or a signal received by the patch 24 is transmitted through the feed lines 26a, 26b. The information is transmitted to the transmitter/receiver via the transmitter/receiver. At this time, the y-axis −Z in FIG.
The directivity pattern in the axial plane is like the field pattern in FIG. 9, and like the embodiments in FIGS. 1 and 2,
Two lobes are formed whose maximum radiation direction is shifted horizontally. Although the field pattern in FIG. 5 appears to be different from that in FIG. 9 because it is shown on a logarithmic scale, substantially the same pattern is formed. Further, the directivity pattern in the X-axis-Z-axis plane of FIG. 8 also shows expansion in the horizontal direction as shown in FIG. 10, and is similar to the pattern in FIG. 9.

In this way, the patch antenna 21 of this embodiment also has horizontal omnidirectional directional characteristics. In particular, this embodiment
Compared to the embodiment shown in FIG. 2 and FIG. 2, the horizontal directivity in the X-axis-Z-axis plane is excellent. That is, in the embodiments shown in FIGS. 1 and 2, there is only one shorting conductor 8, so the directivity pattern in the X-axis-Z-axis plane is
While the spread in the horizontal direction is slightly smaller than in the axis-Z axis plane, in this embodiment, as described above, the y-axis
The pattern is approximately the same as the axial plane. Further, in this embodiment, compared to the embodiments shown in FIGS. 1 and 2, the patch 24 is fixed to the ground plate 23 by the shorting conductors 28a and 28b.
This results in a more stable structure.

FIG. 11 shows a patch antenna according to still another embodiment of the present invention, in which one more pair of shorting conductors is provided in addition to the embodiments shown in FIGS. 7 and 8. That is, a pair of short-circuit conductors 38a and 38b are joined to the outer peripheral edge of the patch 34 of the disk conductor at a symmetrical position with respect to the center 34c of the plate surface, and the patch is on an axis that includes the center 34c of the plate surface and is perpendicular to the axis connecting them. A pair of short circuit conductors 38c and 38d are joined to the outer peripheral edge of 34, and these short circuit conductors 38a to 38d are joined to the ground plate 33. Incidentally, each central angle θ3 of the joining range at this time is also set to 45°.

The patch 34 has a plate surface center 34c and short circuit conductors 38a, 38.
The feeder lines 36a, 36b are connected between the center 34c of the plate surface and the short-circuit conductors 38c, 38d, respectively.
6c and 36d are joined. Furthermore, these power supply lines 36
a to 36d are patches 3 of short-circuit conductors 38a to 38d.
It is preferable to arrange it on the axis connecting the midpoint of each joint portion of No. 4 and the center 34c of the plate surface. The power supply lines 36a to 36d are inserted through through holes (not shown) drilled in the ground plate 33, and housed in the cylinders of the ground wires 35a to 35d joined to the ground plate 33, respectively. The feeder lines 36a to 36d are connected together to a transmitter/receiver (not shown) as in the embodiment shown in FIG. 8, and the grounding lines 35a to 35d are commonly grounded.

FIG. 13 shows the field pattern in the X-axis-Z-axis plane of the directivity pattern according to this embodiment.
Figure 4 shows the connection between the short circuit conductors 38a and 38b and the short circuit conductor 38.
Good horizontal directivity is obtained as shown in the field pattern in the W-axis-Z-axis plane between 38d and 38d. In particular, in this embodiment, compared to the pattern of the X-axis-y-axis plane shown in FIG. 6 of the embodiment described in FIGS. 1 and 2,
As shown in FIG. 15, it is substantially omnidirectional.

That is, the patch antenna 31 of this embodiment has a substantially ideal horizontal omnidirectional directivity characteristic. Further, in this embodiment, the patch 34 is connected to the short circuit conductors 38a to 38d.
is supported at four points and can be firmly fixed to the ground plate 23,
Sufficient strength can be obtained even when mounted in a car as is.

The number of shorting conductors is not limited to one pair, as shown in the shorting conductors 38a to 38d, but two or more pairs may be provided.Furthermore, as shown in FIG. An annular power feeding point 44 on a concentric circle centered on the plate surface center 44c
The power may be supplied from b.

In addition, also in each of the embodiments shown in FIGS. 7, 8, 11, and 12, the short-circuit conductors 28a, 38a to 3
8d and the short-circuit conductor 48, a plurality of reet bins and connection lines may be arranged in parallel in a predetermined range of the outer periphery of each patch 24.34 and the patch 44. Further, the feeder line in the above embodiment may be constructed of a microstrip line as described in, for example, Japanese Utility Model Application No. 50-46038. Furthermore, in any of the embodiments, after masking a predetermined shape part on the front surface and the entire back surface of the dielectric substrate, a conductor is vacuum-deposited to form a conductive layer on the front and back surfaces of the substrate, thereby forming a patch and a back surface, respectively. It is also possible to configure a ground plate.

[Effects of the Invention] Since the present invention is configured as described above, it produces the effects described below.

That is, according to the patch antenna of the present invention, omnidirectional directivity in the horizontal plane can be ensured with a simple structure in which the outer periphery of the flat conductor patch is connected to the ground plate.

Then, a power feeding point is set offset from the center of the circular patch,
By forming a patch antenna in which a ground plate is connected to a predetermined range of the outer periphery including the intersection of the radius passing through this feeding point and the outer periphery of the circular patch, omnidirectional directivity in the horizontal plane can be obtained, as well as the above predetermined range. It is easy to manufacture because it can be easily set.

In particular, by setting the predetermined range at the central angle of 45 degrees of the circular patch, directional characteristics suitable for mobile communication can be obtained.

In addition, in the case where the patch and the ground plate are electrically connected over the entire outer periphery of the above 45° range, it is easy to manufacture, and the strength to support the patch can be obtained without providing a dielectric substrate. It can be easily embedded in the resin outer panel of an automobile.

If the patch is equipped with a pair of shorting conductors that connect the outer edge of the patch to the ground plane, it is possible to ensure good horizontal directivity characteristics even on the vertical plane including the shorting conductor, and it is possible to Furthermore, since it provides a stable support structure, it is suitable for mobile communications.

Furthermore, with the other pair of short-circuited conductors, an extremely good horizontal omnidirectional directivity characteristic can be obtained, and the patch is firmly fixed to the ground plate, so it can be attached to a car as is. Sufficient strength can be ensured.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the patch antenna of the present invention, FIG. 2 is a plan view of the same, and FIG. 3 is a perspective view of a test patch antenna for confirming the operation of the above embodiment. Fourth
The figure is a partial cross-sectional view of the roof of a car equipped with the patch antenna according to the above embodiment, FIG. A directional characteristic diagram of the patch antenna in the X-axis-y-axis plane, FIG. 7 is a sectional view of the patch antenna of another embodiment of the present invention,
8 is a perspective view of the patch antenna, FIG. 9 is a directional characteristic diagram of the patch antenna in the y-axis-Z-axis plane, and FIG. 10 is a directional characteristic diagram in the X-axis-Z-axis plane. 1
1 is a perspective view of a patch antenna according to still another embodiment of the present invention, FIG. 12 is a perspective view of a patch antenna according to another embodiment of the present invention, and FIG. 13 is a y-axis-Z-axis plane in FIG. 11. Fig. 14 is a directional characteristic diagram of the W-axis-Z-axis plane, Fig. 15 is a directional characteristic diagram of the X-axis-y-axis plane, and Fig. 16 is a cross-sectional view of a conventional patch antenna. It is. 1... Patch antenna, 2... Board. 3.23.33.43...Ground plate. 4.24, 34.44...patch. 4 a, 24 d, 24 e, 44
b - feeding point; 4b...Joint part. 4c, 24c, 34c, 44C...center of board surface. 5.25a, 25b, 35a to 35d - ground wire. 6.26a, 26b, 36a to 36d - feeder lines. 8.28a, 28b, 38a to 38d, 48-Short-circuit conductor patent applicant Kojima Press Kogyo Co., Ltd.

Claims (6)

[Claims] (1) A grounding plate made of a flat conductor, a patch made of a flat conductor arranged parallel to the plate surface with a predetermined gap within the outer periphery of the grounding plate, a power supply line connected to the patch, and the grounding plate connected to the ground plate. 1. A microstrip patch antenna comprising a grounding wire connected to a ground plate, wherein at least a part of the outer periphery of the patch is conductively connected to the grounding plate. (2) A grounding plate made of a flat conductor, a circular patch made of a circular conductor arranged parallel to the plate surface with a predetermined gap within the outer periphery of the grounding plate, and a power supply line connected to the circular patch. ,
In the microstrip patch antenna, the feed line is connected to a feed point offset from the center of the plate surface of the circular patch, and the radius of the circular patch passing through the feed point and the A microstrip patch antenna, characterized in that at least a part of a predetermined range of the outer periphery of the circular patch, including the intersection of the outer periphery of the circular patch, is conductively connected to the ground plate. (3) At least a part of the outer periphery of the circular patch, which includes the intersection of the radius passing through the power feeding point and the outer periphery of the circular patch and is within a central angle of 45°, is electrically connected to the ground plate. The microstrip patch antenna according to claim 2, characterized in that the microstrip patch antenna is connected. (4) The microstrip patch antenna according to claim 3, wherein the entire outer peripheral edge of the circular patch within a center angle of 45° is electrically connected to the ground plate. (5) A grounding plate made of a flat conductor, a patch made of a flat conductor arranged parallel to the plate surface with a predetermined gap within the outer periphery of the grounding plate, a power supply line connected to the patch, and the grounding plate connected to the grounding plate. In a microstrip patch antenna comprising a grounding wire connected to a ground plane, at least a pair of short-circuited conductors conductively connect a part of the outer periphery of the patch to the ground plane, the part of which is symmetrically located with respect to the center of the plate surface of the patch. A microstrip patch antenna, characterized in that a feeding point of the feeding line is provided between each of the pair of short-circuited conductors and the center of the plate surface of the patch. (6) Providing another pair of short-circuiting conductors on the outer periphery of the patch on an axis that includes the center of the plate surface of the patch and is substantially perpendicular to the axis connecting the pair of short-circuiting conductors; 6. The microstrip patch antenna according to claim 5, wherein a feeding point of said feeding line is also provided between each of the conductors and the center of the plate surface of said patch.