JPH02256305A - Microstrip antenna - Google Patents

Abstract

PURPOSE:To realize a stable antenna gain immune to the effect of vibration or the like by forming a 1st element, a 2nd element and a ground conductor by means of the vapor-deposition of a conductor on a dielectric base on which a 1st plate face and a 2nd plate face are integrally formed so as to constitute a microstrip antenna. CONSTITUTION:In regard to a dielectric board 2, a 1st plate face 2a of a board shape and a 2nd plate face 2b of disk shape in parallel with the face 2a are connected via a connection part 2c and they are formed integrally. In this case, a connector 7 provided with a ground terminal 5 and a feeder terminal 6 is formed integrally. The ground terminal 5 is formed cylindrical and arranged on the rear face of the 1st plate face 2a. Moreover, the feeder terminal 6 is make of a copper wire, supported to the ground terminal 5 via an insulator 6a and the tip is arranged while being exposed. A radiation element 4 being a conductor layer, a parasitic element 9 and a ground conductor 3 are adhered closely to the front and rear face of the board 2 except for a masked part, the tip of the feeder 6 is bonded to the radiation element 4 and the ground terminal 5 connects electrically to the ground conductor 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microstrip antenna, and more particularly, to a microstrip antenna that includes at least two elements each consisting of a conductor layer formed on a dielectric substrate and a ground conductor.

[Prior Art] In recent years, there has been remarkable progress in reducing the size and weight of antennas, and various microstrip antennas for use in ultra-high frequency bands or ultra-high frequency bands have been constructed by forming radiating elements on printed circuit boards. Among these microstrip antennas, a microstrip patch antenna that uses a resonant element of an open planar circuit made of a circular, rectangular, etc. flat conductor as a radiating element is attracting attention. This includes a flat conductor ground conductor provided on the back side of a flat dielectric printed circuit board, and a circular or rectangular flat conductor radiating element, that is, a patch, formed on the surface by printing technology such as etching. In addition to connecting the power supply line, a grounding wire is connected to the grounding conductor, and the directivity pattern is Z-axis (zenith direction)
It is axially symmetrical in the horizontal plane, making it suitable for antennas for transverse motion communication.

For example, Japanese Patent Publication No. 60-40203 discloses a microstrip antenna in which two radiating elements are arranged overlappingly on a ground conductor.

Further, Japanese Patent Application Laid-Open No. 61-219205 discloses a microstrip antenna in which a parasitic element is disposed opposite to a radiating element, and is intended to improve antenna gain. The technology described in the publication includes a first dielectric plate on which a radiating element and a ground conductor plate are formed, and a second dielectric plate on which a conductor plate serving as a parasitic element is provided so as to face the radiating element. In contrast to the conventional technology in which a third dielectric is interposed between both electric plates, the spacing maintaining portion is extended so as to reach the first dielectric plate from all sides of the second dielectric plate. In addition, the radiating element and the parasitic element are composed of strip line elements.

Furthermore, a microstrip antenna is also known in which one radiating element and a plurality of parasitic elements are arranged overlappingly on a ground conductor.

[Problems to be Solved by the Invention] However, in none of the above-mentioned conventional microstrip antennas, specific means for forming or mounting the radiating element and the parasitic element are not disclosed. At the experimental stage, the above-mentioned elements formed of conductor plates are attached to a dielectric plate, but it is difficult to adjust the positional relationship between the elements. Even if conductor layer elements are formed on a current reader board using printed wiring technology as described above, multiple dielectric boards must be bonded and overlaid, and the relative positions of the elements must be adjusted. Adjusting the relationship is still accompanied by difficulties. Furthermore, when the microstrip antenna is mounted on a moving body or the like, there is a possibility that the positional relationship between the elements may shift due to vibration or the like.

For example, in the technique described in Japanese Patent Laid-Open No. 61-219205, the first dielectric plate and the second dielectric plate are formed separately, and the two are joined via a gap maintaining portion. Therefore, there is a possibility that misalignment occurs during assembly or use, resulting in misalignment between the radiating element and the parasitic element, making it impossible to obtain the desired antenna gain. In particular, in the configuration where the flange of one dielectric plate is connected to the other using screws as described in the example, accurate positioning is difficult, and due to vibrations during use, etc., the initial position between the two is difficult. There is a high possibility that misalignment will occur. Moreover, the stripline element used as the parasitic element is formed on a dielectric film, and then this film is fixed to the 8-electrode board by adhesive, and even in this adhesive process, the radiating element and the parasitic element are connected. There may be a gap between the two.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to prevent misalignment between elements in a microstrip antenna not only during assembly but also during use, and to ensure a desired antenna gain.

[Means for Solving the Problems] In order to achieve the above object, the microstrip antenna of the present invention is formed by integrally connecting a first plate portion and a second plate portion parallel to the first plate portion. A dielectric substrate, the dielectric material except for a predetermined shaped portion of the surface of the first plate surface portion facing the second plate surface portion and the entire back surface, and a predetermined shaped portion of either the front surface or the back surface of the second plate surface portion. A conductor layer formed by vacuum deposition after masking the substrate, comprising a radiating element formed on the surface of the first plate surface, a ground conductor formed on the back surface of the first plate surface, and a conductor layer formed on the second plate surface. The device includes a parasitic element formed on either the front surface or the back surface, a feed line connected to the radiating element, and a ground line connected to the ground conductor.

In the microstrip antenna, the first element may be connected to the feed line to constitute a radiating element, and the second element may be a parasitic element.

Alternatively, two feeding lines may be provided and connected to each of the first element and the second element to form two radiating elements.

In these microstrip antennas, the radiating element and the ground conductor may be short-circuited. Further, the parasitic element and the ground conductor may be short-circuited.

Furthermore, a third plate surface portion parallel to the first and second plate surface portions is integrally connected to the second plate surface portion, and the third plate surface portion has the above-mentioned shapes on either the front surface or the back surface of the third plate surface portion except for a predetermined shaped portion. The third element may be formed by vacuum-depositing a conductor layer after masking the 8-conductor substrate. This third element can constitute a radiating element or a parasitic element.

[Operation] In the microstrip antenna described above, the entire back surface of the first plate surface portion of the dielectric substrate and the predetermined shaped portions of the first plate surface portion and the second plate surface portion are masked. That is, the first plate surface part is masked except for the entire back surface and the circular part of the front surface where a circular radiating element is to be arranged, and the second plate surface part is masked except for the circular part where a circular radiating element is to be disposed, and the second plate surface part is masked except for the circular part on which a circular radiating element is to be disposed. Masked except for the same circular part as above, which is located opposite. Thereafter, a conductor thin film is formed on the dielectric substrate by vacuum deposition. As a result, the first element of the circular conductor layer is formed on the front surface of the first plate surface portion, and the ground conductor of the conductor layer that extends over the entire surface is formed on the back surface. A second element of a conductor layer having the same shape as the first element is formed on either the front or back surface of the second plate surface portion. A feeder line is connected to at least one of the first element and the second element, and a ground line is connected to the ground conductor to form a microstrip antenna.

In the dielectric substrate, the first plate surface portion and the second plate surface portion are integrally connected, and the first element and the second element opposing the same are formed on both plate surface portions by vacuum evaporation. These positional relationships are fixed and do not shift even during use. Thus, at least one of the first element and the second element performs high-gain transmission and reception of electromagnetic waves in the ultra-high frequency band or ultra-high frequency band, and the transmitted and received signals are transmitted via the power supply line.

[Embodiments] Hereinafter, preferred embodiments of the microstrip antenna of the present invention will be described with reference to the drawings.

1 and 2 show a microstrip antenna 1 according to an embodiment of the present invention, in which a ground conductor 3 and a ground conductor 3 according to the present invention are provided on a first plate surface portion 2a and a second plate surface portion 2b of a dielectric substrate 2. A radiating element 4 as one element and a parasitic element 9 as a second element are formed.

The dielectric substrate 2 is formed by connecting a flat first plate surface portion 2a and a circular second plate surface portion 2b parallel thereto via a connecting portion 2c, and these are integrally molded. At this time, as shown in FIG. 2, a connector 7 including a ground terminal 5 and a power supply terminal 6 is integrally molded. The grounding terminal 5 has a cylindrical shape, and the surface of the flange portion formed approximately in the center is the first plate surface portion 2a.
It is placed so that it is exposed on the back side. In addition, the power supply terminal 6
is formed of, for example, a copper wire that extends on the central axis of the ground terminal 5, is supported by the ground terminal 5 via an insulator 6a, and extends to the surface side of the first plate surface portion 2a, with its tip slightly exposed. It is arranged so that

Then, on the front and back surfaces of the dielectric substrate 2, masking is applied to the hatched areas in FIG. Vapor deposition takes place. That is, the conductor is evaporated by heat in a high vacuum and deposited on the front and back surfaces of the dielectric substrate 2. As a result, a conductor thin film, that is, a conductor layer, is formed on the front and back surfaces of the dielectric substrate 2 except for the masked portions. Thus, the radiating element 4, the parasitic element 9, and the ground conductor 3 are formed in close contact with the front and back surfaces of the eight-electrode substrate 2. At this time, the tip of the power supply terminal 6 is connected to the radiation element 4 formed on the surface of the first plate surface portion 2a.
Further, the outer periphery of the cylindrical body and the surface of the flange portion of the grounding terminal 5 are joined to the grounding conductor 3 and electrically connected.

Note that the radiating element 4 and the parasitic element 9 are provided facing each other,
These shapes are considered to be the same, but are not limited to circular shapes.
It may have any shape such as a rectangle. Further, the second plate surface portion 2b does not necessarily have to have the same shape as the parasitic element 9, and may be formed as shown in FIG. Furthermore, in FIGS. 3 and 4, the parasitic element 9 is masked to be deposited on the upper surface side of the second plate surface portion 2b, but as shown in FIG. Second plate surface part 2
In the embodiment shown in FIG. 4, the parasitic element 19 may be formed on the lower surface side of the
Although the radiating element 4 is formed at a position projected onto the second plate surface part 2b perpendicular to the direction a, it may be formed by shifting this by a predetermined distance.In either case, the parasitic element 9 and the radiating element 4 The relative positional relationship between them is fixed, and the desired antenna gain is ensured.

The microstrip antenna 1 is connected to a connector 7 with a coaxial cable (not shown) and to a transmitting/receiving device (not shown). That is, the power supply terminal 6 of the connector 7 constitutes a power supply line according to the present invention, and the ground terminal 5 constitutes a ground line according to the present invention. The microstrip antenna 1 may be fixed or attached to, for example, exterior resin parts such as various spoilers, roof panels, and cover tops of automobiles (not shown), as well as resin parts constituting parts of the car body such as bonnets, luggage doors, and fenders. Can be buried.

According to the microstrip antenna 1 configured as described above, the radiating element 4 functions as a resonant element of an open planar circuit. Therefore, at the time of transmission, a high frequency signal transmitted from a transmitting/receiving device (not shown) via the coaxial cable and the power supply terminal 6 is radiated from the radiating element 4 as a very high frequency wave or an extremely high frequency wave, and at the time of reception, the signal received by the radiating element 4 is transmitted to the power supply terminal 6. and transmitted to the transmitting/receiving device via the coaxial cable. At this time, since the parasitic element 9 is facing the radiating element 4, the microstrip antenna 1
can obtain high gain characteristics.

Moreover, the relative positional relationship between the parasitic element 9 and the radiating element 4 is fixed, and a stable gain can be ensured without any deviation.

6 to 13 show cross sections of other embodiments of the microstrip antenna of the present invention, in which masking is applied to the parts other than the predetermined shape parts, and the first element and the first element are vacuum-deposited with a conductor. Two elements etc. are formed. Incidentally, in FIGS. 6 to 13, the same members as those in the embodiment of FIG. 2 are given the same reference numerals.

In the embodiment shown in FIG. 6, a shorting conductor 8 is provided in addition to the embodiment shown in FIG. has been done. In the embodiment of FIG.
The approximate centers of the radiating element 4 and the parasitic element 9 are connected to the ground conductor 3, and these are configured to be short-circuited. These shorting conductors 8.18 are buried in the dielectric substrate 2 in advance and then the conductors are vacuum-deposited, or they are attached to the dielectric substrate 2 after each element is formed.

In addition to the connector 7 of the embodiment of FIG. 2, the embodiment of FIG.
A second connector 1 is provided, and its power supply terminal 16 is connected to the second
is connected to the radiating element 14 of. That is, the second element referred to in the present invention is also a radiating element, and the second radiating element 14 is formed in the same manner as the radiating element 4 of the embodiment shown in FIG. In this embodiment, the power supply terminal 16 passes through the radiation element 4, but is held so as not to come into contact with it. The embodiment of FIG. 9 has, in addition to the embodiment of FIG. 8, a shorting conductor 18 for connecting the radiating element 4.14 to the ground conductor 3.

In the embodiment shown in FIG. 10, a conductor layer is also formed on the back surface of the second plate surface portion 2b of the dielectric substrate 2 by vacuum deposition, and a second parasitic element 19 is constructed.In the end, two parasitic elements are formed. Elements 9 and 19 are provided. Note that the radiating element 4 is connected to the ground conductor 3 via a short-circuit conductor 8. 11th
In the illustrated embodiment, the radiating element 4 and the second parasitic element 19 are connected to the ground conductor 3 by a short-circuit conductor 18 instead of the short-circuit conductor 8 in the embodiment of FIG. In the embodiment shown in FIG. 12, a second connector 17 is added to the embodiment shown in FIG.
A second radiating element 14 is configured by being connected to the conductor layer on the back surface.

In the embodiment shown in FIG. 13, the connecting portion 2C extends further outward from the surface of the second plate portion 2b, and is supported by the connecting portion 2C, which extends parallel to the first plate portion 2a and the second plate portion 2b. A three-plate surface portion 2d is formed.

Then, the radiation element 4. is formed by vacuum deposition of a conductor on the surface of each plate surface portion. A parasitic element 9 and a second parasitic element 19 are formed. The approximate center of the radiating element 4 is connected to the ground conductor 3 by a shorting conductor 8. Incidentally, as in the above-mentioned embodiment, the parasitic element 9 is also connected to the ground conductor 3 due to the short-circuit conductor.
or connect a second connector to the parasitic element 9
Alternatively, a second radiating element may be configured.

Various embodiments of microstrip antennas have been shown above, but the radiating element 4.14 and the parasitic elements 9, 19 can also be used in rivers by using a conductor layer formed by vacuum deposition on the dielectric substrate 2. Because of this structure, there will be no deviation in the mutual positional relationship during manufacturing. In addition, there is no fear of deviation occurring due to photographing or the like during use, and a stable antenna gain can be ensured. In any of the above embodiments, the first plate surface portion 2a and the second plate surface portion 2b or the third plate surface portion
The gap between the plate surface portion 2d and the plate surface portion 2d may be filled with a dielectric material, or a dielectric plate may be interposed therebetween.

14 and 15 show another embodiment of the present invention, in which the dielectric substrate 2 has a first plate surface portion 2a and a second plate surface portion 2b, which are different from those shown in FIGS. 1 to 3. is formed into a curved shape, that is, a three-dimensional shape, and an opening 2e is formed in the outer periphery of the portion of the dielectric substrate 2 where the radiating element 4 is to be mounted. This frontage 2e is, as shown in FIG.
It is formed substantially perpendicularly to the plate surface of the dielectric substrate 2 so as to face the outer periphery of the range set by the central angle θ of the circular radiating element 4 . Note that when θ is set to 45'', good horizontal plane omnidirectionality can be obtained.

Using this dielectric substrate 2, a connector 7 is provided in the same manner as in the embodiment shown in FIGS. 1 and 2, and a parasitic element 9 is connected.
After masking except for the radiating element 4 part and the outer peripheral side surface part of the radiating element 4 of the opening 2e, vacuum evaporation is performed.
As is clear from the cross-sectional view of FIG. 14, a connection portion 28 is formed of a vapor-deposited conductor, and the ground conductor 3 and the radiating element 4 are connected. That is, the predetermined range of the outer circumferential portion of the radiating element 4 is the joint portion 4.
b, and is connected to the ground conductor 3 via the connecting portion 28, and constitutes the above-mentioned short circuit conductor. In this embodiment, as in the embodiments shown in FIGS. 5 to 13, the feed terminal 6 is connected at a position offset by a predetermined distance from the center 4c of the radiating element 4, forming a feed point 4a. The rest of the configuration is the same as the embodiment shown in FIGS. 1 and 2, so the explanation will be omitted.

In this embodiment, since the joint 4b at the outer periphery of the radiating element 4 is connected to the ground conductor 3 via the connection 28, the directional characteristics of the microstrip antenna are omnidirectional in the horizontal plane. exhibits. Note that this can be easily confirmed by experiment. Therefore, even if the direction of travel changes or the microstrip antenna is mounted on a moving object, stable transmission and reception can be performed regardless of the direction of travel.

Note that instead of the connecting portion 28, a plurality (for example, five) of short-circuit conductors may be arranged in parallel in a predetermined range of the outer circumference of the radiating element 4. In this case, the radiating element 4 is bonded before vacuum evaporation. A plurality of holes may be made in the outer periphery of the capsule. Joint part 4
Although the range of b may be increased or decreased, it is preferably around 45° in order to ensure the desired directivity.

Even when the microstrip antenna is fixed to or buried in the resin body or exterior resin parts of an automobile, it can ensure stable antenna gain without being affected by vibrations or the like. In particular, a microstrip antenna formed into a three-dimensional shape can be easily attached to the above-mentioned components.

Furthermore, the microstrip antenna described above can also be used as a resin part for the exterior of a cabin of a ship or the like.

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

That is, the present invention constitutes a microstrip antenna by forming at least a first element, a second element, and a ground conductor by vacuum deposition of a conductor on a dielectric substrate in which a first plate part and a second plate part are integrally formed. Therefore, there is no misalignment between the first element and the second element during assembly or use, and the desired antenna gain can be ensured. Therefore, even when the microstrip antenna of the present invention is fixed to or buried in, for example, an exterior resin part of an automobile, a stable antenna gain can be ensured without being affected by vibrations or the like.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the microstrip antenna of the present invention, FIG. 2 is a vertical cross-sectional view of the microstrip antenna of FIG. 1, and FIG. 3 is a dielectric composing the microstrip antenna of FIG. FIG. 4 is a perspective view of a dielectric substrate constituting a microstrip antenna according to another embodiment of the present invention, and FIGS. 5 to 13 are microstrip antennas of still other embodiments of the present invention. FIG. 14 is a vertical sectional view of a microstrip antenna according to another embodiment of the present invention, and FIG. 15 is a partially sectional plan view of the microstrip antenna of FIG. 14. 1...Microstrip antenna. 2... Dielectric substrate, 2a... First plate surface portion. 2b...Second plate surface part, 2d...Third plate surface part. 3... Ground conductor, 4... Radiation element (first element). 4a... Feeding point, 4b... Junction, 4c
···center. 5...Grounding terminal (grounding wire). 6...Power supply terminal (power supply line), 7...Connector. 8.18... Short circuit conductor. 9... Parasitic element (second element). 14... Second radiating element, 17... Second connector. 19... Second parasitic element, 28... Connection section. Figure 1 Patent applicant Kojima Press Kogyo Co., Ltd.

Claims (4)

[Claims] (1) a dielectric substrate comprising a first plate surface portion and a second plate surface portion integrally connected to the first plate surface portion and parallel to the first plate surface portion;
After masking the dielectric substrate except for a predetermined shaped portion of the front surface of the first plate surface portion facing the second plate surface portion and the entire back surface and a predetermined shaped portion of either the front surface or the back surface of the second plate surface portion. A conductor layer formed by vacuum deposition, comprising a first element formed on the surface of the first plate surface, a ground conductor formed on the back surface of the first plate surface, and a conductor layer formed on the front and back surfaces of the second plate surface. a second element formed on either side;
A microstrip antenna comprising: a feed line connected to at least one of the first element and the second element; and a ground line connected to the ground conductor. (2) The microstrip antenna according to claim 1, wherein the first element is connected to the feed line to constitute a radiating element, and the second element is a parasitic element. (3) The microstrip antenna according to claim 1, characterized in that two feeder lines are provided and connected to each of the first element and the second element to form two radiating elements. (4) The microstrip antenna according to claim 2 or 3, wherein the radiating element and the ground conductor are short-circuited.