JP6952940B2 - Antenna device - Google Patents

Description

The present disclosure relates to an antenna device of a communication terminal.

In wireless communication such as wireless LAN (Local Area Network), a communication area is formed by a communication terminal master unit serving as an access point, and communication is performed with a communication terminal slave unit in the area. Further, in a sensor network, communication terminals may be connected to each other in a mesh pattern to generate a plurality of communication paths, and multi-hop communication may be performed between the communication terminals.
When the communication terminal slave units are distributed in the communication area formed by one communication terminal master unit, the communication terminal master unit is required to have an omnidirectional radiation pattern in the horizontal plane.
Further, when there are a plurality of communication areas, in order to improve the gain between the communication areas, each communication terminal master unit needs to have a radiation pattern that is directional to each other. In particular, considering the case where a plurality of communication terminal master units are lined up in a row and the communication area is formed continuously in a straight line, the communication terminal master unit is in a linear direction in which the communication area is adjacent, that is, in the communication area. A bidirectional radiation pattern is required in the horizontal plane installed in.

Patent Document 1 discloses a configuration example of a polarization-shared bidirectional antenna using a combination of a reverse-phase excitation type planar antenna and a transmission line type antenna. A rectangular linear conductor is provided on the ground conductor to obtain a figure-eight bidirectional vertically polarized radiation pattern in the horizontal plane, and cuts (dents) are formed on the two opposite sides of the flat conductor. It is disclosed that a bidirectional horizontally polarized radiation pattern is obtained in a horizontal plane by forming a reverse-phase excitation type plane antenna.

Japanese Unexamined Patent Publication No. 2018-61195

With the polarization shared antenna of Patent Document 1, a plurality of bidirectional radiation patterns in the horizontal plane can be obtained, but an omnidirectional radiation pattern cannot be obtained.

In order to realize an omnidirectional radiation pattern, it is necessary to prepare a plurality of antennas having each radiation pattern, and the cost increases due to the increase in the size of the terminal device and the number of antennas to be installed. There was a problem.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a small antenna device in which an omnidirectional antenna in a horizontal plane and a bidirectional antenna in a horizontal plane are integrated.

The antenna device according to the present disclosure includes a flat plate-shaped ground conductor, a flat plate-shaped first conductor plate arranged parallel to the ground conductor and provided with a first hole and a second hole, and parallel to the ground conductor. The first horizontal conductor, which is arranged in, intersects vertically so as to electrically connect with the first conductor plate, the first end connects with the ground conductor, and the second end of the first horizontal conductor. It is inserted vertically into the first hole so as to have space with the first vertical conductor connecting to the first end and the first conductor plate, and the first end is with the second end of the first horizontal conductor. A first linear conductor having a second vertical conductor connected and having a second end connected to a first feeding point, a second horizontal conductor arranged parallel to the ground conductor, and a first conductor plate. A third vertical conductor and a first that intersect vertically to electrically connect with, a first end connecting to the ground conductor, and a second end connecting to the first end of the second horizontal conductor. Inserted vertically into the second hole so as to have space with the conductor plate of, the first end connects to the second end of the second horizontal conductor, the second end connects to the second feeding point A second linear conductor composed of a fourth vertical conductor is arranged perpendicular to the first conductor plate, the first end is connected to the first conductor plate, and the second end is on the ground conductor side. A third linear conductor to be connected to the third feeding point is provided.

According to the present disclosure, it is possible to realize a small antenna device in which an omnidirectional antenna in a horizontal plane and a bidirectional antenna in a horizontal plane are integrated.

It is a block diagram which shows the antenna device which concerns on Embodiment 1. FIG. FIG. 5 is a cross-sectional view taken along the line AA of FIG. 1 showing an example of a first linear conductor. It is BB sectional view of FIG. 1 which shows an example of the 2nd linear conductor. FIG. 5 is a cross-sectional view taken along the line CC of FIG. 1 showing an example of a third linear conductor. FIG. 5 is a cross-sectional view taken along the line CC of FIG. 1 showing an example of a microstrip antenna with a short-circuit conductor configured in an antenna device. It is a graph which showed the radiation pattern in the horizontal plane (in the xy plane) at the frequency f1 of the omnidirectional antenna of the antenna device which concerns on Embodiment 1. FIG. It is a graph which showed the radiation pattern in the horizontal plane (in the xy plane) at the frequency f2 of the bidirectional antenna of the antenna device which concerns on Embodiment 1. FIG. It is a block diagram which shows the antenna device which concerns on Embodiment 2. FIG. It is a block diagram which shows the antenna device which concerns on Embodiment 3. FIG. 9 is a cross-sectional view taken along the line DD of FIG. 9 showing an example of a fourth linear conductor. It is a block diagram which shows the modification of the antenna device which concerns on Embodiment 3. FIG. It is a DD cross-sectional view of FIG. 11 which shows an example of the 2nd conductor plate. It is a block diagram which shows the antenna device which concerns on Embodiment 4. FIG. FIG. 3 is a cross-sectional view taken along the line EE of FIG. 13 showing an example of the first linear conductor. FIG. 3 is a cross-sectional view taken along the line FF showing an example of a second linear conductor. FIG. 3 is a cross-sectional view taken along the line GG of FIG. 13 showing an example of a microstrip antenna with a short-circuit conductor configured in an antenna device. It is a schematic diagram of the current flowing on the 1st linear conductor. It is a graph which showed the radiation pattern in the horizontal plane (in the xy plane) at the frequency f2 of the bidirectional antenna in the horizontal plane of the antenna device of Embodiment 4. It is a graph which showed the radiation pattern in the horizontal plane (in the xy plane) at the frequency f2 of the bidirectional antenna of the antenna device which concerns on Embodiment 4. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1.
FIG. 1 is a configuration diagram showing an antenna device according to the first embodiment. In FIG. 1, the antenna device includes a ground conductor 1, a conductor plate (first conductor plate) 2, a first linear conductor 3, a second linear conductor 4, a first hole 5, and a second hole. 6 and a third linear conductor 7 are provided.

The ground conductor 1 is made of a metal such as copper or aluminum and operates as a ground for an antenna device. In FIG. 1, the ground conductor 1 is shown in the shape of a circular plate, but any shape can be appropriately selected as long as the operation as the ground of the antenna device can be obtained. For example, it may be a square. In the present embodiment, a case where the ground conductor 1 is composed of a disk-shaped conductor as shown in FIG. 1 will be described as an example.

The conductor plate 2 is a flat-plate conductor arranged parallel to the main surface of the ground conductor 1. Any shape can be selected as the planar shape of the conductor plate 2 as long as it is designed to resonate at a predetermined frequency f1, but a circle, a square, or a polygon is usually used. In the present embodiment, a case where the conductor plate 2 is composed of a disk-shaped conductor as shown in FIG. 1 will be described as an example. It is desirable that the center of the ground conductor 1 and the center of the conductor plate 2 be arranged so as to coincide with the normal direction of the ground conductor 1.

The first linear conductor 3 includes a horizontal conductor (first horizontal conductor) 3a, a vertical conductor (first vertical conductor) 3b connected to one end (first end) of the horizontal conductor 3a, and the horizontal conductor 3a. It is a conductor composed of a vertical conductor (second vertical conductor) 3c connected to an end (second end). The total length of the first linear conductor 3 is the sum of the lengths of the horizontal conductor 3a, the vertical conductor 3b, and the vertical conductor 3c. The horizontal conductor 3a is parallel to the ground conductor 1 and the conductor plate 2, and these are arranged in the order of the ground conductor 1, the conductor plate 2, and the horizontal conductor 3a at predetermined intervals.

The vertical conductor 3b is arranged perpendicular to the ground conductor 1 and the conductor plate 2, one end (first end) is connected to the ground conductor 1, and the other end (second end) is one end (second end) of the horizontal conductor 3a. It is connected to the first end). The vertical conductor 3b intersects the conductor plate 2 vertically so as to be electrically connected to the conductor plate 2. The vertical conductor 3c is arranged perpendicular to the ground conductor 1 and the conductor plate 2, and one end (first end) is connected to the other end (second end) of the horizontal conductor 3a.

The other end (second end) of the vertical conductor 3c is arranged in the vicinity of the ground conductor 1, and a high frequency voltage is applied between the ground conductor 1 and the other end (second end) of the vertical conductor 3c. The vertical conductor 3c is inserted vertically into the first hole 5 provided in the conductor plate 2 so as to have a space with the conductor plate 2. A sectional view taken along the line AA of FIG. 1 is shown in FIG. The same reference numerals as those in FIG. 1 indicate the same or corresponding parts. Reference numeral 21 denotes a feeding point (first feeding point) connected to the other end of the vertical conductor 3c.

The second linear conductor 4 includes a horizontal conductor (second horizontal conductor) 4a, a vertical conductor (third vertical conductor) 4b connected to one end (first end) of the horizontal conductor 4a, and the horizontal conductor 4a. It is a conductor composed of a vertical conductor (fourth vertical conductor) 4c connected to an end (second end). The total length of the second linear conductor 4 is the sum of the lengths of the horizontal conductor 4a, the vertical conductor 4b, and the vertical conductor 4c. The horizontal conductor 4a is parallel to the ground conductor 1 and the conductor plate 2, and these are arranged in the order of the ground conductor 1, the conductor plate 2, and the horizontal conductor 4a at predetermined intervals.

The vertical conductor 4b is arranged perpendicular to the ground conductor 1 and the conductor plate 2, one end (first end) is connected to the ground conductor 1, and the other end (second end) is one end (second end) of the horizontal conductor 4a. It is connected to the first end). The vertical conductor 4b intersects the conductor plate 2 vertically so as to be electrically connected to the conductor plate 2. The vertical conductor 4c is arranged perpendicular to the ground conductor 1 and the conductor plate 2, and one end (first end) is connected to the other end (second end) of the horizontal conductor 4a.

The other end (second end) of the vertical conductor 4c is arranged in the vicinity of the ground conductor 1, and a high frequency voltage is applied between the ground conductor 1 and the other end (second end) of the vertical conductor 4c. The vertical conductor 4c is inserted vertically into the second hole 6 provided in the conductor plate 2 so as to have a space with the conductor plate 2. A sectional view taken along line BB of FIG. 1 is shown in FIG. The same reference numerals as those in FIG. 1 indicate the same or corresponding parts. Reference numeral 22 denotes a feeding point (second feeding point) connected to the other end of the vertical conductor 4c.

The total length of the first linear conductor 3 and the total length of the second linear conductor 4 are designed so that the first linear conductor 3 and the second linear conductor 4 resonate at a predetermined frequency f2. .. In the present embodiment, the frequency at which the conductor plate 2 resonates is f1, and the frequency at which the first linear conductor 3 and the second linear conductor 4 resonate is f2, but the frequency f1 and the frequency f2 are the same. It may be different.

The horizontal conductor 3a of the first linear conductor 3 and the horizontal conductor 4a of the second linear conductor 4 are parallel to each other with a predetermined interval, and are opposite to each other with respect to the center of the conductor plate 2. It is arranged so as to be. It is desirable that the first linear conductor 3 and the second linear conductor 4 are arranged so as to be rotationally symmetric (point symmetric) by 180 degrees with respect to the center of the conductor plate 2. Further, when the conductor plate 2 has a rotationally symmetric shape such as a circle or a square, the vertical conductors 3b and 3c of the first linear conductor 3 and the vertical conductors 4b and 4c of the second linear conductor 4 are the centers of the ground conductor 1. It is desirable to arrange it at a position that is rotationally symmetric with respect to 90 degrees.

The third linear conductor 7 is a conductor arranged perpendicular to the ground conductor 1 and the conductor plate 2 and having one end (first end) connected to the conductor plate 2. The other end (second end) of the third linear conductor 7 is arranged in the vicinity of the ground conductor 1, and a high frequency voltage is applied between the ground conductor 1 and the other end of the third linear conductor 7. ..
A cross-sectional view taken along the line CC of FIG. 1 is shown in FIG. The same reference numerals as those in FIG. 1 indicate the same or corresponding parts. Reference numeral 23 denotes a feeding point (third feeding point) connected to the other end of the third linear conductor 7. In FIG. 1, one end of the third linear conductor 7 and the connection point of the conductor plate 2 coincide with the center of the conductor plate 2, but it is desired between the third linear conductor 7 and the conductor plate 2. If impedance matching is obtained, the connection point between one end of the third linear conductor 7 and the conductor plate 2 does not necessarily have to coincide with the center of the conductor plate 2.

Next, the operation of the antenna device according to the present embodiment will be described. Since the transmitting antenna and the receiving antenna are reversible, the operation as the transmitting antenna will be described here.

Since the conductor plate 2 is designed to resonate at a predetermined frequency f1, when a high frequency voltage is applied to the feeding point 23, the conductor plate 2 and the ground conductor 1 pass through the third linear conductor 7. A high-frequency voltage is applied between them, and electric charges move between them, causing an alternating current to flow. Further, in the antenna device according to the present embodiment, the ground conductor 1 and the conductor plate 2 are electrically connected by the vertical conductor 3b of the first linear conductor 3 and the vertical conductor 4b of the second linear conductor 4. Therefore, a microstrip antenna with a short-circuit conductor is constructed.

FIG. 5 shows a cross-sectional view taken along the line CC of FIG. 1, focusing only on this microstrip antenna with a short-circuit conductor. The same reference numerals as those in FIG. 1 indicate the same or corresponding parts. The ground conductor 1 and the conductor plate 2 are electrically connected by the vertical conductor 3b of the first linear conductor 3 and the vertical conductor 4b of the second linear conductor 4, and the conductor plate 2 is centered. Since the electric current flows radially from the conductor to the outside, an omnidirectional radiation pattern is generated in the horizontal plane of the conductor plate 2 as in the capacitively loaded monopole antenna with a short-circuit conductor. Therefore, the ground conductor 1 and the conductor plate 2 provide an omnidirectional antenna in the horizontal plane.

When a high frequency voltage is applied to the feeding point 21, an alternating current flows through the first linear conductor 3. At this time, based on the principle of mirror image, a mirror image of the first linear conductor 3 is considered with the ground conductor 1 as a plane of symmetry, and the first linear conductor 3 is a loop antenna arranged perpendicular to the ground conductor 1. Can be seen. The vertical conductor 3b of the first linear conductor 3 is connected not only to the ground conductor 1 but also to the conductor plate 2, but when the first linear conductor 3 resonates at a predetermined frequency f2, the first is Since the stationary wave node on the linear conductor 3 of 1 is generated on the vertical conductor 3b, even if the vertical conductor 3b is connected to the conductor plate 2, the influence on the operation as a loop antenna is small.

The vertical conductor 3c of the first linear conductor 3 is also arranged so as to penetrate the conductor plate 2, but is arranged so as to pass through the first hole 5 provided in the conductor plate 2 and has no electrical connection. By selecting the size of the first hole 5 so that the vertical conductor 3c and the conductor plate 2 are not capacitively coupled, the influence on the operation as a loop antenna can be eliminated. The same can be considered for the second linear conductor 4. Since the first linear conductor 3 operates as a loop antenna arranged perpendicular to the ground conductor 1, its radial directivity in the horizontal plane is 8-shaped, and the direction orthogonal to the horizontal conductor 3a (+ x in FIG. 1). , -X direction) directivity occurs. Similarly, the second linear conductor 4 has a figure eight-shaped radiation directivity that maximizes the gain in the + x and −x directions.

Since the first linear conductor 3 and the second linear conductor 4 are arranged so as to be opposite to each other with respect to the center of the conductor plate 2, the voltage applied to the first linear conductor 3 Assuming that the phase difference φ of the voltage applied to the second linear conductor 4 is 180 °, the radio wave radiated from the first linear conductor 3 and the second linear conductor in the + x and −x directions in the horizontal plane. The radio waves radiated from the conductor 4 strengthen each other. Therefore, the ground conductor 1, the first linear conductor 3, and the second linear conductor 4 provide a bidirectional antenna in the horizontal plane. Although the case where the first linear conductor 3 and the second linear conductor 4 are arranged so as to be opposite to each other with respect to the center of the conductor plate 2 has been described, the first linear conductor 3 has been described. And the second linear conductor 4 are preferably point-symmetrical with respect to the center of the conductor plate 2.

Next, the results of electromagnetic field simulation performed with the antenna device configuration of this embodiment are shown. FIG. 6 is a graph showing the emission pattern in the horizontal plane (in the xy plane) at the frequency f1 of the omnidirectional antenna in the horizontal plane of the antenna device of the present embodiment. The thick line in the figure shows the strength in the XY plane. In the present embodiment, the distance between the ground conductor 1 and the conductor plate 2 is 0.024λ1, the diameter of the conductor plate 2 is 0.29λ1, and the distance from the center of the conductor plate 2 of the first linear conductor 3 is 0. It was set to .06λ1. λ1 is a wavelength with respect to the frequency f1. As is clear from FIG. 6, it can be seen that the ground conductor 1 and the conductor plate 2 provide an omnidirectional antenna in the horizontal plane.

FIG. 7 is a graph showing the emission pattern in the horizontal plane (in the xy plane) at the frequency f2 of the bidirectional antenna in the horizontal plane of the antenna device of the present embodiment. In the present embodiment, the length of the horizontal conductor 3a of the first linear conductor 3 is 0.28λ2, and the length of the vertical conductors 3b and 3c is 0.12λ2. λ2 is a wavelength with respect to the frequency f2. A second linear conductor 4 is provided so as to be point-symmetrical with the center of the conductor plate 2 with respect to the first linear conductor 3, and the distance between the first linear conductor 3 and the second linear conductor 4 is set. It was set to 0.28λ2. The frequency f1 and the frequency f2 are different values, and f1 <f2 (λ1> λ2). As is clear from FIG. 7, the bidirectional antenna in the horizontal plane of the antenna device according to the present embodiment has a bidirectional radiation pattern having directivity in the ± x direction. Therefore, it can be seen that the bidirectional antenna in the horizontal plane is obtained by the ground conductor 1, the first linear conductor 3, and the second linear conductor 4.

As described above, in the antenna device according to the present embodiment, the ground conductor 1 and the conductor plate 2 form an omnidirectional antenna in the horizontal plane, and the ground conductor 1, the first linear conductor 3, and the second linear are formed. A horizontal bidirectional antenna is formed by the conductor 4, and the vertical conductor 3b of the first linear conductor 3 and the vertical conductor 4b of the second linear conductor 4 are shared with the short-circuit conductor of the omnidirectional antenna in the horizontal plane. The omnidirectional antenna in the horizontal plane and the bidirectional antenna in the horizontal plane are integrated. As a result, it is possible to realize an omnidirectional radiation pattern in the horizontal plane and a bidirectional radiation pattern in the horizontal plane without increasing the number of installed antennas, and to obtain an antenna device having a small installation area.

Embodiment 2.
In the first embodiment, a case where an air layer is formed between the conductor plate 2 arranged parallel to the main surface of the ground conductor 1 has been described. In the present embodiment, a case where a dielectric is sandwiched between the ground conductor 1 and the conductor plate 2 will be described.
FIG. 8 is a configuration diagram showing an antenna device according to the present embodiment. In FIG. 8, the same configurations as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. The difference between the antenna device according to the present embodiment and the first embodiment is that the dielectric plate 8 is newly arranged between the ground conductor 1 and the conductor plate 2.

The dielectric plate 8 is a flat-plate-shaped dielectric having a predetermined relative permittivity, and a ground conductor 1 is formed on one plane and a conductor plate 2 is formed on the other surface. In the present embodiment, as shown in FIG. 8, the dielectric plate 8 has a disk shape having a predetermined thickness, but is arbitrary within the design range, such as a square plate shape or a polygonal plate shape. The shape can be selected.
Further, in FIG. 8, the ground conductor 1 is represented as having the same shape so as to coincide with the entire one plane of the dielectric plate 8, but as described above, the ground conductor 1 is grounded only on a part of one surface of the dielectric plate 8. The conductor 1 may be formed.

The conductor plate 2 is designed in consideration of the relative permittivity and the thickness of the dielectric plate 8 so as to resonate at a predetermined frequency f1 as in the first embodiment.

In the antenna device according to the present embodiment, as the dielectric plate 8, for example, a dielectric substrate in which copper foil is attached to both sides can be used. In this case, the ground conductor 1 and the conductor plate 2 can be processed into a predetermined shape by etching both sides of the dielectric plate 8. Further, in the dielectric plate 8, a through hole (not shown) is formed in a portion where the vertical conductor 3b of the first linear conductor 3 and the vertical conductor 4b of the second linear conductor 4 are arranged. Can be passed through the dielectric plate 8 and the electrical connection between the ground conductor 1 and the conductor plate 2 can be secured.
On the other hand, in the dielectric plate 8, by forming holes (not shown) in the portions where the vertical conductors 3c and the vertical conductors 4c are arranged, these conductors can be penetrated through the dielectric plate 8.

As described above, in the antenna device according to the present embodiment, by using the dielectric plate 8 between the ground conductor 1 and the conductor plate 2, a manufacturing method suitable for mass production such as etching processing of the dielectric substrate Can be used, and an antenna device can be obtained at low cost.

Embodiment 3.
In the first embodiment, an antenna device capable of obtaining both an omnidirectional radiation pattern in a horizontal plane and a bidirectional radiation pattern in a horizontal plane has been described in one antenna device. In the present embodiment, a case where the radiation pattern is omnidirectional in the horizontal plane will be further described.
FIG. 9 is a configuration diagram showing an antenna device according to the present embodiment. In FIG. 9, the same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. The difference between the antenna device according to the present embodiment and the first embodiment is that a third hole 10 is newly provided in the conductor plate 2 and a fourth linear conductor 9 is newly arranged.

The fourth linear conductor 9 is a conductor arranged perpendicular to the ground conductor 1 and the conductor plate 2 along the central axis of the conductor plate 2. One end (first end) of the fourth linear conductor 9 is vertically inserted into a third hole 10 provided in the conductor plate 2 so as to have a space with the conductor plate 2, and the other end (second end). The end) is arranged in the vicinity of the ground conductor 1, and a high frequency voltage is applied between the ground conductor 1 and the other end of the fourth linear conductor 9. A sectional view taken along line DD of FIG. 9 is shown in FIG. The same reference numerals as those in FIGS. 2 to 4 and 9 indicate the same or corresponding parts. Reference numeral 24 denotes a feeding point (fourth feeding point) connected to the other end of the fourth linear conductor 9.

In the antenna device according to the first embodiment, the third linear conductor 7 may be arranged at the center of the conductor plate 2, but in the antenna device according to the present embodiment, the fourth linear conductor 7 is arranged. Since the conductor 9 is arranged at the center of the conductor plate 2, the third linear conductor 7 needs to be arranged at a predetermined distance from the center of the conductor plate 2. The distance between the third linear conductor 7 and the center of the conductor plate 2 is appropriately designed at a position where desired impedance matching can be obtained.

The length of the fourth linear conductor 9 is designed to resonate at a predetermined frequency f3. However, the frequency f3 may be the same as or different from the frequency f1 or the frequency f2. At this time, when a high-frequency voltage is applied to the feeding point 24, electric charges move to both of them and an alternating current flows. That is, the fourth linear conductor 9 operates as a monopole antenna that resonates at the frequency f3, and an omnidirectional radiation pattern in the horizontal plane is obtained.

In a horizontal in-plane omnidirectional antenna (microstrip antenna with a short-circuit conductor) composed of a ground conductor 1 and a conductor plate 2, it occurs between the ground conductor 1 and the conductor plate 2 near the center of the conductor plate 2 due to structural symmetry. The electric field strength becomes very small. Therefore, even if the fourth linear conductor 9 is newly arranged along the central axis of the conductor plate 2, it affects the operation of the omnidirectional antenna in the horizontal plane composed of the ground conductor 1 and the conductor plate 2. Never.

As described above, in the antenna device according to the present embodiment, by providing the fourth linear conductor 9 along the central axis of the conductor plate 2, a new in-plane omnidirectional antenna operating at the frequency f3 is provided. It can be integrally configured, and the number of elements can be increased without increasing the size of the antenna device.

It is also possible to combine the dielectric plate 8 according to the second embodiment with the antenna device according to the present embodiment. In this case, as described in the second embodiment, a manufacturing method excellent in mass production can be used, and the cost of the antenna device can be reduced.

Further, in order to lower the posture of the fourth linear conductor 9, it is possible to use it as a so-called top-loading antenna. FIG. 11 shows a modified example of the antenna device according to the present embodiment. In FIG. 11, reference numeral 11 denotes a second conductor plate. The same reference numerals as those in FIG. 8 indicate the same or corresponding parts. A cross-sectional view taken along the line DD of FIG. 11 is shown in FIG. The same reference numerals as those in FIGS. 2 to 4 and 9 indicate the same or corresponding parts. The second conductor plate 11 is electrically connected to one end (first end) of the fourth linear conductor 9. Any shape can be selected as long as the shape of the second conductor plate 11 is designed together with the fourth linear conductor 9 so as to resonate at a predetermined frequency f3, but the fourth linear conductor 9 A shape having rotational symmetry with respect to the axial direction of is desirable. For example, a circle, a square, a regular polygon, or the like is selected.

Embodiment 4.
In the first embodiment, a configuration using a loop antenna arranged perpendicular to the ground conductor 1 with a bidirectional radiation pattern in the horizontal plane as an antenna element has been described. In the present embodiment, an antenna configuration in which the symmetry of the antenna configuration is better and the symmetry of the radiation pattern in the horizontal plane is better will be described.

FIG. 13 is a configuration diagram showing an antenna device according to the fourth embodiment. In FIG. 13, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. The difference between the antenna device according to the present embodiment and the first embodiment is that a vertical conductor (third vertical conductor) 3d is newly provided in the first linear conductor 3, and the second linear conductor is provided. A vertical conductor (third vertical conductor) 4d is provided in No. 4, and each constitutes a T-shaped monopole antenna.

The first linear conductor 3 includes a horizontal conductor (first horizontal conductor) 3a, a vertical conductor (first vertical conductor) 3b connected to one end (first end) of the horizontal conductor 3a, and the horizontal conductor 3a. It is a conductor composed of a vertical conductor (second vertical conductor) 3c connected to an end (second end) and a vertical conductor (third vertical conductor) 3d connected to the center of the horizontal conductor 3a. The shape of the first linear conductor 3 is preferably symmetrical with respect to the axis including the vertical conductor 3d. At this time, the total length of the first linear conductor 3 as an antenna is a combination of half the length of the horizontal conductor 3a, the length of the vertical conductor 3b (or the vertical conductor 3c), and the length of the vertical conductor 3d.

The horizontal conductor 3a is parallel to the ground conductor 1 and the conductor plate 2, and these are arranged in the order of the ground conductor 1, the conductor plate 2, and the horizontal conductor 3a at predetermined intervals. The vertical conductor 3b is arranged perpendicular to the ground conductor 1 and the conductor plate 2, one end (first end) is connected to the ground conductor 1, and the other end (second end) is one end (second end) of the horizontal conductor 3a. It is connected to the first end). At this time, the vertical conductor 3b intersects the conductor plate 2 vertically so as to be electrically connected to the conductor plate 2.

The vertical conductor 3c is arranged perpendicular to the ground conductor 1 and the conductor plate 2, one end (first end) is connected to the ground conductor 1, and the other end (second end) is the other end of the horizontal conductor 3a. It is connected to (second end). At this time, the vertical conductor 3c intersects the conductor plate 2 vertically so as to be electrically connected to the conductor plate 2.

The vertical conductor 3d is arranged perpendicular to the ground conductor 1 and the conductor plate 2, and one end (first end) is connected to the center of the horizontal conductor 3a. The other end (second end) of the vertical conductor 3d is arranged in the vicinity of the ground conductor 1, and a high frequency voltage is applied between the ground conductor 1 and the other end (second end) of the vertical conductor 3d. At this time, the vertical conductor 3d is inserted vertically into the first hole 5 provided in the conductor plate 2 so as to have a space with the conductor plate 2. A sectional view taken along line EE of FIG. 13 is shown in FIG. The same reference numerals as those in FIG. 13 indicate the same or corresponding parts. Reference numeral 21 denotes a feeding point (first feeding point) connected to the other end of the vertical conductor 3d.

The second linear conductor 4 includes a horizontal conductor (second horizontal conductor) 4a, a vertical conductor (first vertical conductor) 4b connected to one end (first end) of the horizontal conductor 4a, and the horizontal conductor 4a. It is a conductor composed of a vertical conductor (fifth vertical conductor) 4c connected to an end (second end) and a vertical conductor (sixth vertical conductor) 4d connected to the center of the horizontal conductor 4a. The shape of the second linear conductor 4 is preferably symmetrical with respect to the axis including the vertical conductor 4d. At this time, the total length of the second linear conductor 4 as an antenna is a combination of half the length of the horizontal conductor 4a, the length of the vertical conductor 4b (or the vertical conductor 4c), and the length of the vertical conductor 4d.

The horizontal conductor 4a is parallel to the ground conductor 1 and the conductor plate 2, and these are arranged in the order of the ground conductor 1, the conductor plate 2, and the horizontal conductor 4a at predetermined intervals. The vertical conductor 4b is arranged perpendicular to the ground conductor 1 and the conductor plate 2, one end (first end) is connected to the ground conductor 1, and the other end (second end) is one end (second end) of the horizontal conductor 4a. It is connected to the first end). At this time, the vertical conductor 4b intersects the conductor plate 2 vertically so as to be electrically connected to the conductor plate 2.

The vertical conductor 4c is arranged perpendicular to the ground conductor 1 and the conductor plate 2, one end (first end) is connected to the ground conductor 1, and the other end (second end) is the other end of the horizontal conductor 4a. It is connected to (second end). At this time, the vertical conductor 4b intersects the conductor plate 2 vertically so as to be electrically connected to the conductor plate 2.

The vertical conductor 4d is arranged perpendicular to the ground conductor 1 and the conductor plate 2, and one end (first end) is connected to the center of the horizontal conductor 4a. The other end (second end) of the vertical conductor 4d is arranged in the vicinity of the ground conductor 1, and a high frequency voltage is applied between the ground conductor 1 and the other end (second end) of the vertical conductor 4d. At this time, the vertical conductor 4d is inserted vertically into the second hole 6 provided in the conductor plate 2 so as to have a space with the conductor plate 2. A sectional view taken along line FF of FIG. 13 is shown in FIG. The same reference numerals as those in FIG. 13 indicate the same or corresponding parts. Reference numeral 22 denotes a feeding point (second feeding point) connected to the other end of the vertical conductor 4d.

The total length of the first linear conductor 3 and the total length of the second linear conductor 4 are designed so that the first linear conductor 3 and the second linear conductor 4 resonate at a predetermined frequency f2. .. In the present embodiment, the frequency at which the conductor plate 2 resonates is f1, and the frequency at which the first linear conductor 3 and the second linear conductor 4 resonate is f2, but the frequency f1 and the frequency f2 are the same. It may be different.

The horizontal conductor 3a of the first linear conductor 3 and the horizontal conductor 4a of the second linear conductor 4 are parallel to each other with a predetermined interval, and are opposite to each other with respect to the center of the conductor plate 2. It is arranged so as to be. It is desirable that the first linear conductor 3 and the second linear conductor 4 are arranged so as to be rotationally symmetric (point symmetric) by 180 degrees with respect to the center of the conductor plate 2.

Further, when the conductor plate 2 has a rotationally symmetric shape such as a circle or a square, the vertical conductors 3b, 3c, 3d of the first linear conductor 3 and the vertical conductors 4b, 4c, 4d of the second linear conductor 4 are ground. It is desirable that the conductor 1 is arranged at a position that is rotationally symmetric by 90 degrees with respect to the center of the conductor 1.

A sectional view taken along line GG of FIG. 13 is shown in FIG. The same reference numerals as those in FIG. 13 indicate the same or corresponding parts. Reference numeral 23 denotes a feeding point (third feeding point) connected to the other end of the third linear conductor 7. In FIG. 13, one end of the third linear conductor 7 and the connection point of the conductor plate 2 coincide with the center of the conductor plate 2, but it is desired between the third linear conductor 7 and the conductor plate 2. If impedance matching is obtained, the connection point between one end of the third linear conductor 7 and the conductor plate 2 does not necessarily have to coincide with the center of the conductor plate 2. Further, in FIG. 16, the feeding points 21, 22, and 23 are arranged in the same linear shape, but the feeding points do not necessarily have to be in the same linear shape.

With the above configuration, the ground conductor 1 and the conductor plate 2 form a microstrip antenna with a short-circuit conductor. Compared to the first embodiment, the number of short-circuit conductors has increased from two to four in the present embodiment, but since the connection points are rotationally symmetric with respect to the conductor plate 2, the same as in the first embodiment. An omnidirectional radiation pattern in the horizontal plane is generated in the horizontal plane, and the omnidirectional antenna in the horizontal plane is obtained by the ground conductor 1 and the conductor plate 2.

When a high frequency voltage is applied to the feeding point 21, an alternating current flows through the first linear conductor 3. A schematic diagram of the current flowing on the first linear conductor 3 is shown in FIG. The current I1 flowing on the vertical conductor 3d branches toward each end of the horizontal conductor 3a at the center of the horizontal conductor 3a. Assuming that the branched currents are I2 and I3, respectively, the amplitudes of the currents I2 and I3 are the same, and the currents flow in opposite directions. Therefore, when viewed from the + x and −x directions in the horizontal plane, the radio waves radiated from the current I2 and the radio waves radiated from the current I3 cancel each other out. Therefore, the radiation from the vertical conductor 3d is mainly emitted, and the first linear conductor 3 can be regarded as a T-shaped monopole antenna.

The vertical conductors 3b and 3c of the first linear conductor 3 are connected to the ground conductor 1 and the conductor plate 2, but the first linear conductor 3 is connected to the ground conductor 1 and the conductor plate 2 at a predetermined frequency f2 in consideration of the parasitic capacitance caused by the vertical conductors 3b and 3c. Designed to resonate. The vertical conductor 3d of the first linear conductor 3 is also arranged so as to penetrate the conductor plate 2, but is arranged so as to pass through the first hole 5 provided in the conductor plate 2 and has no electrical connection. By selecting the size of the first hole 5 so that the vertical conductor 3c and the conductor plate 2 are not capacitively coupled, the influence on the operation as a monopole antenna can be eliminated. The same can be considered for the second linear conductor 4.

Since the first linear conductor 3 and the second linear conductor 4 are arranged so as to be opposite to each other with respect to the center of the conductor plate 2, it is the first from the observation point on the y-axis in the horizontal plane. The distance of the linear conductor 3 to the vertical conductor 3d and the distance of the second linear conductor 4 to the vertical conductor 4d are equal.
Therefore, assuming that the phase difference φ between the voltage applied to the first linear conductor 3 and the voltage applied to the second linear conductor 4 is 180 °, it is perpendicular to the radio wave radiated from the current flowing through the vertical conductor 3d. The radio waves radiated from the current flowing through the conductor 4d cancel each other out and do not radiate in the + y and −y directions.
On the other hand, since there is a distance difference between the vertical conductor 3d and the vertical conductor 4d at the observation point on the x-axis, a phase difference occurs according to the distance between the vertical conductor 3d and the vertical conductor 4d. The radio wave radiated from the linear conductor 3 and the radio wave radiated from the second linear conductor 4 intensify each other. Therefore, the ground conductor 1, the first linear conductor 3, and the second linear conductor 4 suppress the radiation in the ± y direction, and obtain a bidirectional antenna in the horizontal plane that radiates in the ± x direction.
Although the case where the first linear conductor 3 and the second linear conductor 4 are arranged so as to be opposite to each other with respect to the center of the conductor plate 2 has been described, the first linear conductor 3 has been described. And the second linear conductor 4 are preferably point-symmetrical with respect to the center of the conductor plate 2.

In the antenna device of the present embodiment, since the monopole antenna fed from the center of the horizontal conductor is constructed by the first linear conductor 3 and the second linear conductor 4, the symmetry of the radiation directivity in the horizontal plane is maintained. The effect of improvement can be expected. In order to show the effect of the bidirectional antenna in the horizontal plane of this embodiment, the electromagnetic field simulation result is shown. Since the operation of the omnidirectional antenna in the horizontal plane is the same as that of the first embodiment, the description thereof will be omitted below. In actual use, the antenna device is often housed in a case. Therefore, the radiation pattern when the antenna device is housed in a metal case having a square opening and a predetermined size is shown.

FIG. 18 is a graph showing the emission pattern in the horizontal plane (in the xy plane) at the frequency f2 of the bidirectional antenna in the horizontal plane of the antenna device of the present embodiment. In the present embodiment, the length of the horizontal conductor 3a of the first linear conductor 3 is 0.28λ2, and the length of the vertical conductors 3b, 3c, and 3d is 0.09λ2. λ2 is a wavelength with respect to the frequency f2. A second linear conductor 4 is provided so as to be point-symmetrical with the center of the conductor plate 2 with respect to the first linear conductor 3, and the distance between the first linear conductor 3 and the second linear conductor 4 is set. It was set to 0.28λ2.

For comparison, FIG. 19 shows a radiation pattern at a frequency f2 of the bidirectional antenna in the horizontal plane when the antenna device of the first embodiment is housed in the same metal case.

As is clear from FIG. 18, the bidirectional antenna in the horizontal plane of the antenna device according to the present embodiment has a bidirectional radiation pattern having directivity in the ± x direction. Further, from the comparison with FIG. 19, it can be seen that the symmetry of the radiation pattern is better and the gain in the ± direction is improved as compared with the bidirectional antenna in the horizontal plane of the first embodiment. Therefore, it can be seen that the ground conductor 1, the first linear conductor 3, and the second linear conductor 4 of the present embodiment provide a more symmetric and high-gain bidirectional antenna in the horizontal plane. ..

As described above, in the antenna device according to the present embodiment, the centrally fed T-shaped monopole antenna is formed by the first linear conductor 3 and the second linear conductor 4, so that the symmetry is good. It is possible to realize an in-horizontal bidirectional antenna that can obtain a radiation pattern, and to obtain an antenna device with high gain even in actual use.

It is also possible to combine the dielectric plate 8 according to the second embodiment with the antenna device according to the present embodiment. In this case, as described in the second embodiment, a manufacturing method excellent in mass production can be used, and the cost of the antenna device can be reduced.

Further, it is also possible to combine the antenna device according to the present embodiment with the fourth linear conductor 9 according to the third embodiment. In this case, as described in the third embodiment, the omnidirectional antenna in the horizontal plane operating at the frequency f3 can be newly integrally configured, and the antenna device can be increased in number without increasing the size.

In the first to fourth embodiments of the present invention, the first linear conductor 3, the second linear conductor 4, the fourth linear conductor 9, and the second conductor plate 11 are described as self-supporting conductors. However, in practical use, it is possible to use a structure that supports these conductors within the scope of the design, or to form a predetermined conductor pattern on the resin surface by a method such as a three-dimensional patterning technique.

It should be noted that the combination of each embodiment, the modification of each arbitrary component of the embodiment, or the omission of any component in each of the embodiments is possible.

The antenna device according to the present disclosure can be used, for example, in a communication terminal.

1 ground conductor, 2 conductor plate, 3 first linear conductor, 3a horizontal conductor, 3b vertical conductor, 3c vertical conductor, 3d vertical conductor, 4 second linear conductor, 4a horizontal conductor, 4b vertical conductor, 4c vertical Conductor, 4d vertical conductor, 5 first hole, 6 second hole, 7 third linear conductor, 8 dielectric plate, 9 fourth linear conductor, 10 third hole, 11 second conductor Boards, 21, 22, 23, 24 Feed points.

Claims (8)

Flat plate-shaped ground conductor and
A flat plate-shaped first conductor plate arranged parallel to the ground conductor and provided with a first hole and a second hole,
A first horizontal conductor arranged parallel to the ground conductor, vertically intersecting the first conductor plate so as to electrically connect, a first end connecting to the ground conductor, and a second end. Is inserted vertically into the first hole so as to have a space with the first vertical conductor connecting to the first end of the first horizontal conductor and the first conductor plate, and the first end is said to be said. A first linear conductor having a second vertical conductor that connects to the second end of the first horizontal conductor and the second end connects to the first feeding point.
A second horizontal conductor arranged parallel to the ground conductor, vertically intersecting the first conductor plate so as to electrically connect, a first end connecting to the ground conductor, and a second end. Is inserted vertically into the second hole so as to have a space with a third vertical conductor connecting to the first end of the second horizontal conductor and the first conductor plate, and the first end is said to be said. A second linear conductor consisting of a fourth vertical conductor that connects to the second end of the second horizontal conductor and the second end connects to the second feeding point.
A third line that is arranged perpendicular to the first conductor plate, the first end connecting to the first conductor plate, and the second end connecting to the third feeding point on the ground conductor side. With the conductor
Antenna device with. The antenna according to claim 1, wherein the first horizontal conductor and the second horizontal conductor are arranged at positions parallel to each other and point-symmetrical to the central axis of the first conductor plate. Device. The antenna device according to claim 2, wherein the plane shape of the first conductor plate is point-symmetrical. The antenna device according to claim 3, wherein the first linear conductor and the second linear conductor are point-symmetrical with respect to the center of the first conductor plate. The antenna device according to any one of claims 1 to 4, wherein a dielectric is provided between the ground conductor and the first conductor plate. The first conductor plate has a third hole in the center and has a third hole.
A claim that includes a fourth linear conductor that is vertically inserted into the third hole so as to have a space with the first conductor plate, and one end on the ground conductor side is connected to a fourth feeding point. The antenna device according to any one of claims 1 to 5. A claim comprising a second conductor plate in which the first conductor plate is arranged parallel to a surface opposite to the surface facing the ground conductor and electrically connected to the other end of the fourth linear conductor. Item 6. The antenna device according to item 6. Flat plate-shaped ground conductor and
A flat plate-shaped first conductor plate arranged parallel to the ground conductor and provided with a first hole and a second hole,
A first horizontal conductor arranged parallel to the ground conductor, vertically intersecting the first conductor plate so as to electrically connect, a first end connecting to the ground conductor, and a second end. Vertically intersects the first vertical conductor connecting to the first end of the first horizontal conductor and the first conductor plate so as to electrically connect, and the first end connects to the ground conductor. Then, it is inserted vertically into the first hole so that the second end has a space with the second vertical conductor connecting with the second end of the first horizontal conductor and the first conductor plate. A first having a third vertical conductor in which a first end connects between the first and second ends of the first horizontal conductor and the second end connects to a first feeding point. With a linear conductor,
A second horizontal conductor arranged parallel to the ground conductor, vertically intersecting the first conductor plate so as to electrically connect, a first end connecting to the ground conductor, and a second end. Vertically intersects the fourth vertical conductor connecting to the first end of the first horizontal conductor and the first conductor plate so as to electrically connect, and the first end connects to the ground conductor. Then, it is inserted vertically into the second hole so that the second end has a space with the fifth vertical conductor connecting with the second end of the second horizontal conductor and the first conductor plate. A second consisting of a sixth vertical conductor whose first end connects between the first and second ends of the second horizontal conductor and whose second end connects to a second feeding point. With a linear conductor,
A third line that is arranged perpendicular to the first conductor plate, the first end connecting to the first conductor plate, and the second end connecting to the third feeding point on the ground conductor side. With the conductor
Antenna device with.

Images