JP4680097B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device, and more particularly to an orthogonally polarized wave shared antenna device that radiates two orthogonally polarized waves suitable for communication / radar and the like.

2. Description of the Related Art Conventionally, a patch antenna for dual orthogonal polarization is composed of a radiating conductor of a dielectric substrate and a metal conductor film as a ground conductor. The straight line connecting one power supply pin and the straight line connecting the center of the radiation conductor and the second power supply pin for exciting and radiating the second linearly polarized wave orthogonal to the first linearly polarized wave are orthogonal to each other. It has a structure to be arranged, separate power supply circuits are connected to both power supply pins, and power is supplied to them by switching to radiate orthogonal two polarization components (see, for example, Patent Document 1 or Patent Document 2) ).
A method of reducing the cross polarization level by shifting the position of the two feeding points has also been proposed (see, for example, Patent Document 3).

JP 2000-312112 A JP 2004-266499 A JP 2003-224416 A

However, since the conventional orthogonal dual-polarization shared patch antenna is often configured on a dielectric substrate, there is a problem that material selection is limited when used in space.
In addition, in the case of an orthogonal two-polarization patch antenna with a cavity, there is a problem that the cross polarization level is high and the isolation rises at both feeding points.

  An object of the present invention is to provide an antenna device in which an orthogonal dual-polarization shared patch antenna with a cavity is made of only metal and the level of a cross-polarized component of a radiated wave is low.

An antenna device according to the present invention includes a cavity that is open on one surface and surrounded by a metal wall, a radiation conductor that is disposed at a predetermined position on the open surface of the cavity, and a vertical surface extending from the bottom surface of the cavity. And a short pin made of a conductor column that supports a point where the electric field of the discharge conductor becomes zero, and the radiating conductor has a first feeding point for exciting and radiating the first linearly polarized wave, and A second feeding point for exciting and radiating a second linearly polarized wave orthogonal to the first linearly polarized wave is provided, and a point where the electric field of the radiation conductor becomes zero is defined as a cross polarized wave component. And placed on the open surface at a predetermined distance from the center of the open surface of the cavity so as to reduce the level .

  The effect of the antenna device according to the present invention is that the short pin plays a role of fixing the radiation conductor to the open surface portion of the cavity, and the antenna device can be composed entirely of metal conductors without using a dielectric substrate. Therefore, there is no deterioration due to aging due to radiation even when used in space.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of an antenna apparatus according to Embodiment 1 of the present invention. FIG. 1A is a plan view of the antenna device. FIG.1 (b) is sectional drawing of the antenna apparatus in the AA sectional line of Fig.1 (a).
An antenna device 1 according to Embodiment 1 of the present invention constitutes an orthogonal dual-polarization patch antenna with a cavity 3. As shown in FIG. 1, the antenna device 1 has a dish-like metal conductor 2 that forms a cavity 3 with a central portion 2a recessed in a square bowl shape, and a vertical position from a central point 2b of the central portion 2a of the metal conductor 2. A short pin 4 that is a conducting pillar, a square radiating conductor 5 fixed to the tip of the short pin 4 at a center point 5a, a feeding pin 6a as two feeding lines for vertical polarization excitation feeding the radiating conductor 5, and A feed pin 6b is provided as a feed line for horizontal polarization excitation.

The radiation conductor 5 is connected to the metal conductor 2 by a short pin 4 at the center point of the bottom of the cavity 3. The central point 5a of the radiating conductor 5 is a point where the electric field is zero. Therefore, even if the short pin 4 which is a conductor column is provided at that position, the characteristic of the patch antenna is not affected.
Here, xy coordinates are set on the radiation conductor 5. The center of the xy coordinate is made to coincide with the center point 5a of the radiation conductor 5, and the x axis 8a is set to be orthogonal to one side of the square. As a result, the y axis 8b is orthogonal to the other side of the square.
The feed pin 6a for vertical polarization excitation is connected to the portion of the radiation conductor 5 at a predetermined distance from the center point 5a on the x-axis 8a passing through the center point 5a of the radiation conductor 5. Further, the feed pin 6b for horizontally polarized wave excitation is connected to a portion of the radiation conductor 5 at a position away from the center point 5a on the y-axis 8b passing through the center point 5a of the radiation conductor 5.
Then, by adjusting a predetermined distance from the center point 5a, impedance matching with the vertically polarized wave excitation feed circuit 11 and the horizontally polarized wave excitation feed circuit 12 connected to each of the feed pins 6a and 6b is achieved. .
In addition, the outer surface 3a of the cavity 3 and the outer shape of the radiation conductor 5 are square so that the horizontal polarization and the vertical polarization have the same characteristics, and the positions of the feed pins 6a and 6b are from the center point 5a of the radiation conductor 5. The same distance is set.

FIG. 2 is a plan view of the radiation conductor 5 depicting the relationship between the polarization direction of the radiated radio wave and the feed pins 6a and 6b to be excited. FIG. 2A shows the relationship when vertically polarized radio waves are radiated. FIG. 2B shows the relationship when horizontally polarized radio waves are radiated.
Next, the operation of the antenna device 1 according to the first embodiment will be described.
The antenna device 1 is configured such that one of the feed pins 6a is switched by switching between a vertically polarized wave excitation feed circuit 11 connected to the feed pin 6a and a horizontal polarization excitation feed circuit 12 connected to the feed pin 6b. 6b are excited. When the feed pin 6a is excited, as shown in FIG. 2 (a), vertically polarized electromagnetic waves are radiated, and when the feed pin 6b is excited, as shown in FIG. 2 (b). Horizontally polarized electromagnetic waves are emitted.

In the antenna device 1 according to the first embodiment, the short pin 4 plays a role of fixing the radiation conductor 5 to the open surface portion 3a of the cavity 3, and all of the antenna device 1 is used without using a dielectric substrate. Can be composed of a metal conductor, so there is no deterioration due to aging due to radiation even when used in space.
In addition, since no dielectric substrate is used, the cost is low and the weight can be reduced.
Further, the presence of the short pin 4 can reduce the isolation between the power supply pins 6a and 6b by adjusting the thickness thereof.

  Moreover, since all are comprised with a metal conductor, a process is easy, and as a processing method, the hole for passing the cavity 3, the short pin 4, and the electric power feeding pins 6a and 6b by cutting a metal plate is used, for example. There is a method in which the radiation conductor 5 provided at once and processed separately is connected by soldering, welding, or the like, and finally the feed pins 6a and 6b are passed through the holes and the tip is connected to the radiation conductor 5. Further, the radiation conductor 5 can be integrally manufactured by cutting a metal plate.

  In the first embodiment, the rectangular patch antenna as shown in FIG. 1 has been described. However, the present invention is not limited to this, and the present invention can be applied to a circular patch antenna or a patch antenna having a shape similar thereto. At that time, the shape of the cavity is similar to that.

Embodiment 2. FIG.
FIG. 3 is a configuration diagram of an antenna apparatus according to Embodiment 2 of the present invention. FIG. 3A is a plan view of the antenna device. FIG. 3B is a cross-sectional view of the antenna device taken along the line BB in FIG.
The antenna device 1B according to the second embodiment of the present invention is different from the antenna device 1 according to the first embodiment in the positions of the radiating conductor 5 and the short pin 4 in the cavity 3, and the other points are the same. Similar parts are denoted by the same reference numerals, and description thereof is omitted.
The radiation conductor 5 according to the first embodiment is supported in the cavity 3 by the short pin 4 so that the center point 5a is located at the center point 3b of the open surface 3a. The radiation conductor 5 is supported in the cavity 3 by a short pin 4 at a position offset from the center point 3b of the surface 3a where the center point 5a is open.

That is, the radiation conductor 5 has a predetermined distance in the x-axis 8a direction (arrow V shown in FIG. 3A) and a predetermined distance in the y-axis 8b direction from the center point 3b of the open surface 3a of the cavity 3. It is arranged at a position horizontally moved by the arrow W (illustrated in FIG. 3A). The short pin 4 is also horizontally moved by the same distance as the horizontal movement distance of the radiation conductor 5 so that one end is connected to the center point 5a of the radiation conductor 5. The operation of the antenna device 1B according to the second embodiment is performed. Since the operation is the same as that of the antenna device 1 according to the first embodiment, description thereof is omitted.

FIG. 4 is a plan view of the radiation conductor in which the flowing current is illustrated. FIG. 4A shows a current flowing through the radiation conductor according to the first embodiment. FIG. 4B illustrates the current flowing through the radiation conductor according to the second embodiment.
When the radiating conductor 5 according to the first embodiment is fed from the feed pin 6a and subjected to vertical polarization excitation, as shown in FIG. 4A, the main polarization component current 15 flowing through the radiating conductor 5 is x It flows on the shaft 8a. Further, the current 16 flowing in the direction of the power supply pin 6b due to the coupling between the power supply pins is coupled with the power supply pin 6a due to the presence of the power supply pin 6b for horizontal polarization, and the magnitude caused by the amount of the connection. Flows parallel to the y-axis 8b. Since this is a component orthogonal to the main polarization component current 15, the radiated wave corresponding to this current 16 becomes a cross polarization component.

On the other hand, when the radiation conductor 5 according to the second embodiment is fed from the feed pin 6a and is vertically polarized, the radiation conductor 5 is parallel to the x-axis and y-axis directions in the surface 3a where the cavity 3 is opened. Since it is moving, in addition to the main polarization component current 15 parallel to the x-axis 8a and the current 16 due to coupling between the feed pins, the magnitude caused by the parallel movement amount of the radiation conductor 5 from the principle of perturbation in the cavity 3 Thus, a current 17 parallel to the y-axis 8b and in the direction opposite to the current 16 flows.
Since the current 17 flows in this way, the radiated wave corresponding to the current 17 cancels the radiated wave corresponding to the current 16, so that the level of the cross polarization component of the radiated wave can be reduced. This is a cause of gain reduction when the level of the cross polarization component is high, and it is not possible to achieve isolation between polarizations.

FIG. 5 is a graph showing the angle dependence of the main polarization component and the cross polarization component of the E-plane radiation pattern when the radiation conductor 5 is arranged at the center of the cavity 3 and when it is horizontally moved from the center of the cavity 3. It is. FIG. 6 is a graph showing the angle dependence of the main polarization component and the cross polarization component of the H-plane radiation pattern when the radiation conductor 5 is arranged at the center of the cavity 3 and when it is horizontally moved from the center of the cavity 3. It is.
By shifting the radiation conductor 5 from the center of the cavity 3 as in the second embodiment, as shown in FIGS. 5 and 6, the level of the cross polarization component is reduced in both the E plane radiation pattern and the H plane radiation pattern. Has been.

FIG. 7 is a graph showing the isolation between the feed pin 6a and the feed pin 6b when the radiation conductor 5 is arranged at the center of the cavity 3 and when it is horizontally moved from the center of the cavity 3.
By shifting the radiation conductor 5 from the center of the cavity 3 as in the second embodiment, the level of the cross polarization component is reduced as shown in FIG. 7, so that the isolation is also reduced.

  Note that the case where the power supply pin 6b is fed for horizontal polarization excitation is the same as the case where the vertical polarization is excited. That is, by feeding the feed pin 6b, a main polarization component current parallel to the y-axis 8b flows, and a current parallel to the x-axis 8a flows due to the mutual coupling between the feed pin 6b and the feed pin 6a. Radiates polarization components. However, by shifting the radiating conductor 5 from the center of the cavity 3, a current corresponding to the perturbation principle is parallel to the x-axis 8a and a current opposite to the current generated by mutual coupling is generated, which cancels out. Therefore, the level of the cross polarization component of the radiated wave can be reduced.

  As described above, the level of the cross polarization component of the radiation wave is reduced by moving the radiation conductor 5 on the open surface 3a of the cavity 3 without changing the relative positional relationship between the short pin 4 and the feed pins 6a and 6b. Therefore, the patch antenna is designed before the radiation conductor 5 is moved, and the amount of movement of the radiation conductor 5 is adjusted while considering the amount of reduction in the level of the cross polarization component. You can do it.

In addition, the antenna device 1B according to the second embodiment is also excellent in workability because it is formed by integrating only the metal conductor, similarly to the antenna device 1 according to the first embodiment.
Further, as shown in FIG. 8, when the length of the short pin 4 and the feed pins 6 a and 6 b is adjusted to shift the vertical position of the radiation conductor 5 from the bottom surface of the cavity 3 from the surface 3 a where the cavity 3 is opened, The radiation pattern shape (directivity) of the patch antenna can be changed.

  In the antenna device 1B according to the second embodiment, since the radiation conductor 5 is shifted from the center of the cavity 3, the cross polarization component due to the coupling between the feed pins of the radiation wave is canceled by the perturbation principle. Cross polarization components can be generated, and the overall cross polarization components can be reduced.

  In the second embodiment, the rectangular patch antenna as shown in FIG. 3 has been described. However, the present invention is not limited to this, and the present invention can be applied to a circular patch antenna or a patch antenna having a shape similar thereto. At that time, the shape of the cavity is similar to that.

Embodiment 3 FIG.
FIG. 9 is a configuration diagram of an antenna apparatus according to Embodiment 3 of the present invention. FIG. 9A is a plan view of the antenna device according to the third embodiment. FIG. 9B is a cross-sectional view of the antenna device taken along the line CC in FIG. 9A.
An object according to the third embodiment of the present invention is an antenna device in which the level of the cross-polarized component of the radiated wave is reduced even in the case of a patch antenna configured using a dielectric substrate that is difficult to use in outer space. Is to provide 1C. Therefore, similarly to the antenna device 1B according to the second embodiment, the center point 26a of the radiating conductor film 26 is shifted from the center point 28b of the open surface portion 28a of the cavity 28 that is electromagnetically opened.

  The antenna device 1C according to the third embodiment includes a first metal conductor film 22 formed on the back surface of the dielectric substrate 21 and a second central portion 23 formed excluding the square central portion 23 on the surface of the dielectric substrate 21. The metal conductor film 24, the through hole 25 that conducts the first metal conductor film 22 at a position overlapping the inner edge 24 a of the second metal conductor film 24 in the thickness direction of the dielectric substrate 21, and the surface of the dielectric substrate 21. A square radiating conductor film 26 formed in the central portion 23 so as to be separated from the second metal conductor film 24, the first metal conductor film 22 and the hole 27 penetrating the dielectric substrate 21, and one end of the radiating conductor. Feeding pins 28a and 28b for vertical polarization excitation and horizontal polarization excitation connected to the membrane 26 are provided.

In the cavity 29 according to the third embodiment, three surfaces are blocked electromagnetically by the through holes 25, the bottom surface is blocked by the first metal conductor film 22 surrounded by the through holes 25, and the remaining one surface is opened electromagnetically. The open surface portion 29a is formed.
The radiation conductor film 26 according to the third embodiment is formed at the central portion 23 on the surface of the dielectric substrate 21 surrounded by the through hole 25. When the center point 26a of the radiation conductor film 26 is the origin of the xy coordinates and the x axis 8a is set so as to be orthogonal to one side of the radiation conductor film 26, the x axis 8a and the y axis 8b correspond to the corresponding sides of the central portion 23, respectively. The radiation conductor film 26 is disposed at a position moved along a predetermined distance along

Starting from the metal conductor film 24 on the surface of the dielectric substrate 21, one of the second metal conductor films 24 is formed so that the radiation conductor film 26 is formed at a position offset from the open surface portion 29a of the cavity 29 and its center point 29b. The portion is removed by etching treatment, and a plurality of through holes 25 are arranged along the outer periphery of the removed portion, and the first metal conductor film 22 and the second metal conductor film 24 are made conductive. Power is supplied to each of the two orthogonally polarized waves from the power supply pins 28a and 28b.
A vertical polarization excitation power supply circuit 11 and a horizontal polarization excitation power supply circuit 12 for exciting vertical polarization and horizontal polarization are connected to corresponding power supply pins 28a and 28b. It is desirable that the interval between the through holes 25 be sufficiently short with respect to the wavelength at the operating frequency.
Note that the operation of the antenna device 1C according to the third embodiment is the same as that of the antenna device 1B according to the second embodiment, and a description thereof will be omitted.

  Such an antenna device 1C according to the third embodiment can be manufactured on the dielectric substrate 21 by an easy technique such as an etching process and addition of feeding means, and can reduce the level of the cross polarization component of the radiated wave.

FIG. 10 is a plan view of an antenna device 1 </ b> D in which feed lines 31 and 32 for feeding a radiation conductor film 26 provided on the dielectric substrate 21 are provided on the dielectric substrate 21.
The feed lines 31 and 32 are constituted by a microstrip line and a coplanar line. When the feed line is wired to the metal conductor film portion on the same surface as the open surface portion 29a of the cavity 29, a coplanar line is used, and in the open surface portion 29a of the cavity 29, the conductor surface at the bottom of the cavity 29 is grounded. It becomes a strip line. For this reason, an alignment converter (not shown) may be provided at the open surface end of the cavity 29. The advantage of this structure is that it can be easily configured only by the etching process.

Further, since a plurality of dielectric substrates can be stacked, for example, a parasitic element is provided above the cavity patch antenna, and it is possible to easily widen the frequency band or control the radiation directivity.
In addition, since the fabrication is performed by etching, the antenna can be easily arrayed.

It is a block diagram of the antenna apparatus concerning Embodiment 1 of this invention. It is a top view of the radiation conductor which drew the relationship between the polarization direction of the radio wave to radiate, and the feed pin to excite. It is a block diagram of the antenna apparatus concerning Embodiment 2 of this invention. It is a top view of the radiation conductor in which the flowing electric current was illustrated. It is a graph which shows each angle dependence of the main polarization component and cross polarization component of an E surface radiation pattern when a radiation conductor is arranged in the center of a cavity and when it moves horizontally from the center of the cavity. It is a graph which shows the angle dependence of each of the main polarization component and the cross polarization component of the H-plane radiation pattern when the radiation conductor is arranged at the center of the cavity and when it is horizontally moved from the center of the cavity. It is a graph which shows the isolation between a feed pin when a radiation conductor is arrange | positioned in the center of a cavity, and when it moves horizontally from the center of a cavity. FIG. 10 is a cross-sectional view of another example of the antenna device according to the second embodiment. It is a block diagram of the antenna apparatus concerning Embodiment 3 of this invention. FIG. 10 is a plan view of another example of the antenna device according to the third embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Antenna apparatus, 2 Metal conductor, 3 Cavity, 4 Short pin, 5 Radiation conductor, 6a, 6b Each feed pin, 8a x axis, 8b y axis, 11 Vertical polarization excitation feed circuit, 12 Horizontal polarization excitation feed Circuit, 15 Main polarization component current, 16, 17 current, 21 Dielectric substrate, 22 Metal conductor film, 23 Center part, 24 Metal conductor film, 25 Through hole, 26 Radiation conductor film, 27 holes, 28 Cavity, 28a, 28b Feed pin, 29 Cavity, 31, 32 Feed line.

Claims (4)

A cavity that is open on one side and surrounded by metal walls on the other,
A radiating conductor disposed at a predetermined position on the open surface of the cavity;
A short pin made of a conductor column that supports the point where the electric field of the discharge conductor is zero, which stands upright from the bottom surface of the cavity;
With
The radiation conductor is configured to excite and radiate a first feed point for exciting and radiating the first linearly polarized wave and a second linearly polarized wave orthogonal to the first linearly polarized wave. 2 feed points are provided, and the point where the electric field of the radiation conductor becomes zero is separated from the center of the open surface of the cavity by a predetermined distance so that the level of the cross polarization component is reduced. An antenna device, characterized in that the antenna device is arranged on a surface that is formed. 2. The antenna device according to claim 1 , wherein the length of the pillar of the short pin is changed, and the radiation power is adjusted by shifting the surface of the radiation conductor from the open surface of the cavity. A first metal conductor covering the back surface of the dielectric substrate, a second metal conductor covering the surface except for a central portion of the surface of the dielectric substrate, and the first metal conductor at a position surrounding the central portion; A cavity formed by a through hole connecting the second metal conductor, a radiation conductor formed at a central portion of the surface and spaced apart from the second metal conductor, and a first straight line on the radiation conductor An antenna comprising: a first feed line for exciting and radiating a polarized wave; and a second feed line for exciting and radiating a second linearly polarized wave orthogonal to the first linearly polarized wave. In the device
The antenna device according to claim 1, wherein the radiating conductor is formed on the surface such that a center point of the radiating conductor is shifted from a center point of the central portion so that a level of a cross polarization component is reduced . The first and second feed lines are feed pins that pass through holes that penetrate the first metal conductor and the dielectric substrate, or strip lines that are formed on the surface. 3. The antenna device described in 3 .

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