JP2010226165A - Array antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microstrip array antenna having a structure for facilitating approach of an adjacent unit array antenna, and suppressing easily interference between them. <P>SOLUTION: In one side 11a of a feeding strip line 11, first radiation antenna elements 111a-111e constituting five first short piece radiating elements are sloped and connected at an equal interval, respectively. The arrangement period is in agreement with a guide wavelength λ<SB>g</SB>. Meanwhile, in another side 11b of the feeding strip line 11, first radiation antenna elements 111f-111i constituting four first short piece radiating elements are sloped and connected at an equal interval, respectively. The nine first radiation antenna elements 111a-111i have all jointly the same structure, and the length is λ<SB>g</SB>/4. Each edge e1 of a side not connected to the feeding strip line 11 of the first radiation antenna elements 111a-111i is shorted at a ground connecting plate 103 on the back, respectively. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an array antenna device in which a plurality of array antennas are arranged in parallel on a plane.

8A and 8B are a plan view and a side view of a conventional microstrip array antenna, respectively. In this microstrip array antenna 900, a ground plate 903 is formed on the back surface of a dielectric substrate 901, and a unit array antenna 910 and a unit array antenna 920 are formed by a strip conductor 902 on the opposite surface thereof. The connection portion 904 is connected to the feeding point 905. The unit array antenna 910 includes a linear strip line 11 having a longitudinal direction in a certain direction, and radiation antenna elements 12a to 12i connected to the side of the strip line 11 at an oblique angle. It consists of The length of each radiating antenna element (12a to 12i) is set to about half of the wavelength of the radio wave propagating on the stripline 11 (in-tube wavelength λ _g ). Further, installation interval of the radiating antenna element (12a-12i) in the longitudinal direction of the strip line 11 is also set to approximately half of the wavelength lambda _g. The unit array antenna 920 is also formed in the same shape as the unit array antenna 910. Here, if the relative permittivity of the dielectric substrate 901 is about 2 that is suitable for radio wave radiation as an antenna, the distance dx between the center lines of both unit array antennas is half of the wavelength λ ₀ of the free space of the radio wave to be used. Is bigger than.

Japanese Patent No. 3306592 JP 2000-31736 A

  For example, in such a microstrip array antenna 900, if adjacent unit array antennas 910 and 920 approach each other and electromagnetically interfere with each other, it is difficult to form a desired sharp pencil beam in each desired direction. Problems such as errors in received data are likely to occur.

  Therefore, in order to quantitatively verify the interference action between adjacent unit array antennas in this way, the inventors of the present application assume a simple local model (FIG. 9) of the microstrip array antenna. A simulation was conducted on power leakage between array antennas. FIG. 9 is a plan view of the simplified model 10 assumed here. The dielectric substrate 901 has a ground plate on the back surface, and the strip lines 11 and 21 are formed in parallel. The distance between the center lines of the strip lines 11 and 12 is 2.0 mm, and the radiating antenna element 12a is inclined with respect to the strip line 11 and is fed only in the vicinity of one apex angle of the rectangular shape. It is connected to the strip line 11. Further, the radiating antenna element 21a is inclined with respect to the strip line 21 and is connected to the feeding strip line 21 only in the vicinity of one rectangular vertex. Symbols eg1 and eg2 indicate field emission edges, respectively.

  FIG. 10 is a graph illustrating a simulation of the intensity of a signal leaking to Port 4 when a signal is input from Port 1 in the above-described local simplified model 10 of the microstrip array antenna. The amount of power leakage from Port 1 to Port 4 is relatively high at −28.48 dB, for example, at 76.50 GHz, which indicates that there is a non-negligible interference between adjacent unit array antennas. . This is probably because the edges eg1 and eg2 are antinodes, and the edge eg1 of the radiating antenna element 12a propagates radio waves to the strip line 21 and the like in the vicinity thereof. For this reason, the conventional microstrip array antenna formed by arranging a plurality of unit array antennas close to each other has a problem that unnecessary interference is likely to occur between adjacent unit array antennas. For this reason, in such a conventional apparatus, it is not always easy to realize a desired directivity. In addition, an unexpected detection error may easily appear.

On the other hand, as disclosed in Patent Document 2, for example, in the field of phase monopulse antennas, there is a demand for the distance between the phase centers of adjacent unit array antennas to be half or less of the free space wavelength λ ₀ .

FIG. 11 illustrates a plan view of a conventional phase monopulse antenna. This conventional microstrip array antenna 800 is very similar to the microstrip array antenna 900 of FIG. 8, and the unit array antenna 811 and the unit array antenna 812 have the same configuration. These strip conductors are formed on a dielectric substrate having a ground plate on the back surface. Stripline 21, the stripline 11 are arranged parallel to the distance dx between the both center lines is greater than half the free-space wavelength lambda ₀ of the radio wave _{(λ 0/2 <dx)} . In this case, as illustrated in FIG. 12, the relationship between the phase difference Δ detected from each received wave of both unit array antennas and the arrival angle θ of the incoming wave at that time is −π / 2 <θ <π Since it is not a monovalent function in the range of / 2, and as shown in the figure, the period is a periodic function smaller than π, the azimuth angle θ cannot be uniquely determined from the phase difference Δ.

Therefore, a configuration has been conceived in which the distance between the phase centers A and B is as narrow as possible. FIG. 13 shows the configuration. In this way, by shifting the unit array antenna 821 by α in the longitudinal direction, providing an offset α between the strip line 11 and the strip line 12, and bringing the unit array antenna 811 and the unit array antenna 821 close to each other in parallel, In this configuration, the left and right unit array antennas (811, 821) are nested. According to this configuration, the distance dx between the center lines of the two strip line, it is possible to set the lambda _0/2 or less.

However, according to such a configuration, as shown in FIG. 13, the straight line connecting the phase centers A and B of each unit array antenna is rotated by an angle φ from the original position in FIG. The output signal includes a component in a direction different from the desired direction, which becomes an error factor in direction detection. That is, when configuring a phase monopulse antenna is easy to set without causing such ramifications, the distance dx between the center lines of the two strip line (11,21) λ _0/2 below is not.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide an arrangement of adjacent unit array antennas in an array antenna apparatus in which a plurality of predetermined unit array antennas are arranged in parallel on a plane. It is to realize an array antenna apparatus having a structure that facilitates the approach and easily suppresses the interference between them.

A first invention for solving the above-described problem is a microstrip array antenna in which a feed line and a radiating element are formed by a strip conductor on the surface of a dielectric substrate having a ground conductor on the back surface. A first array antenna in which a plurality of rectangular first radiating elements are spaced apart from each other along a first feed line extending in a direction and a straight line, and a second feed line extending in a straight line in a y-axis direction And at least two array antennas with a second array antenna having a plurality of rectangular second radiating elements spaced apart from each other, spaced apart in the x-axis direction perpendicular to the y-axis direction, and arranged in parallel In the array antenna device,
The first radiating element disposed in the region between the first feed line and the second feed line has a first connection portion connected to the first feed line and a first end on the side facing the first connection portion. The first short-piece radiation connected to the ground conductor is a length between the first and second sections that is ¼ of the guide wavelength of the radio wave propagating through the first feeder line at a predetermined operating frequency. It is composed of elements.

  Here, the number of array antennas is arbitrary as long as it is plural. The first and second terms refer to one array antenna and components of the antenna when attention is paid to two adjacent array antennas among a plurality of array antennas arranged in parallel. 1 is attached, and the other array antenna and the component parts of the antenna are attached secondly, and are used to distinguish the two. In the case of not attaching the first and second, it is not necessary to distinguish between them, and both are indicated. In a plurality of array antennas, at least one set of array antennas may be composed of the first array antenna and the second array antenna of the present invention. The radiating element may be disposed on only one side along one side of the feed line, or may be disposed on both sides along both sides. Further, an array antenna in which the radiating element is disposed on both sides of the feed line and an array antenna in which the radiating element is disposed only on one side of the feed line may be used in combination. Further, regarding the two array antennas arranged on the outermost side in a plurality of arrayed antennas, the radiating elements may not be arranged on the outer side of the feed line.

  The length of the rectangular first radiating element is set between the first connecting portion connected to the first feeding line and the first end that is the side away from the first feeding line facing the first connecting portion. It is defined by the length of. Similarly, the length of the rectangular second radiating element is set such that the second connecting portion connected to the second feeding line and the second end portion that is a side away from the second feeding line facing the second connecting portion. It is defined by the length between.

  The first short-piece radiating element is defined as a radiating element in which the length of the first radiating element is ¼ of the guide wavelength, and the first end is connected to the ground conductor and grounded. The second short-piece radiating element is defined as a radiating element in which the length of the second radiating element is ¼ of the guide wavelength and the second end is connected to the ground conductor and grounded. Further, the first long piece radiating element is defined as a radiating element in which the length of the first radiating element is ½ of the guide wavelength and the first end is an open end. The second long piece radiating element is defined as a radiating element in which the length of the second radiating element is ½ of the guide wavelength and the second end is an open end.

  The present invention is characterized in that all of the first radiating elements disposed in the region between the first feeding line and the second feeding line are configured by short-piece radiating elements. For a first radiating element that does not exist between the first feeding line and the second feeding line, for example, the first radiating element connected to the outer sides of the feeding lines of the array antennas at both ends of the plurality of array antennas, The first short piece radiating element, the first long piece radiating element, or a mixture thereof may be used. In all of the following cases, the two outermost array antennas may satisfy this relationship. Further, the second radiating element may or may not exist in the region between the first feeding line and the second feeding line. Regarding the arrangement of the radiating elements, the following various modes are conceivable.

  First, in the region between the first feed line and the second feed line, there can be a configuration in which only the first short piece radiating element exists and the second radiating element does not exist. That is, the first short piece radiating elements are arranged only on one side of the first feed line, and the second short piece radiating element is far from the first feed line of the second feed line. This is a case of being arranged along the side edge.

Second, there is a case where a first short piece radiating element and a second short piece element are present in a region between the first feed line and the second feed line.
Thirdly, the first short piece radiating element and the second long piece element are present in the region between the first feed line and the second feed line.

From these, the following inventions exist.
The second invention is characterized in that, in the first invention, only the first short piece radiating element is disposed in a region between the first feeding line and the second feeding line.
In a third aspect based on the first aspect, the second radiating element disposed in the region between the first feed line and the second feed line is connected to the second feed line. And the second end on the side facing the second connecting portion is ¼ of the in-tube wavelength of the radio wave propagating through the second feed line at a predetermined operating frequency, and the second end The section is composed of a second short-piece radiating element connected to a ground conductor.
In a fourth aspect based on the first aspect, the second radiating element disposed in a region between the first feed line and the second feed line is connected to the second feed line. The length between the second end portion on the side facing the second connecting portion and the second connecting portion is a length that is ½ of the in-tube wavelength of the radio wave propagating through the second feed line at a predetermined operating frequency, The end portion is constituted by a second long piece radiating element which is an open end.

  Further, in the region between the first feed line and the second feed line, the first short piece radiating element and the first long piece radiating element are mixed with respect to the first radiating element, and the second short piece with respect to the second radiating element. The radiating element and the second long piece radiating element may be mixed.

Accordingly, a fifth invention is a microstrip array antenna in which a feed line and a radiating element are formed by a strip conductor on the surface of a dielectric substrate having a ground conductor on the back surface, and extends linearly in the y-axis direction. A first array antenna having a plurality of rectangular first radiating elements spaced apart from each other along the first feed line, and a plurality of rectangular shapes along the second feed line extending linearly in the y-axis direction. In the array antenna apparatus, in which at least two array antennas with a second array antenna arranged with the second radiating elements are spaced apart in the x-axis direction perpendicular to the y-axis direction and arranged in parallel,
The first radiating element disposed in the region between the first feed line and the second feed line has a first connection portion connected to the first feed line and a first end on the side facing the first connection portion. The first short piece radiating element connected to the ground conductor has a length between the first portion and a length of ¼ of the guide wavelength of the radio wave propagating through the first feed line at a predetermined operating frequency. And the length between the first connection portion and the first end portion is ½ of the in-tube wavelength of the radio wave propagating through the first feed line at a predetermined operating frequency, and the first end portion is open. The first long piece radiating element which is an end is composed of a mixture along the y-axis direction,
The second radiating element disposed in the region between the first feed line and the second feed line has a second connection portion connected to the second feed line and a second end on the side facing the second connection portion. The second short piece radiating element connected to the ground conductor, the length between the first portion and the second portion being a quarter length of the guide wavelength of the radio wave propagating through the second feed line at a predetermined operating frequency And the length between the second connection portion and the second end portion is ½ of the in-tube wavelength of the radio wave propagating through the second feed line at a predetermined operating frequency, and the second end portion is open. The second long piece radiating element as an end is composed of a mixture along the y-axis direction,
The second long piece radiating element is disposed at a position where the second end portion faces the first end portion of the first short piece radiating element, and the second short piece radiating element has a second end portion of the first long piece radiating element. It is arrange | positioned in the position which faces the 1st edge part of this.

  In the present invention, in the region between the first feed line and the second feed line, the first short piece radiating element and the first long piece radiating element are mixedly arranged along the first feed line. The second long piece radiating element is arranged opposite to the first short piece radiating element, and the second short piece radiating element is arranged opposite to the first long piece radiating element. It is a feature. The first short piece radiating element and the first long piece radiating element can be mixed in any way, but the first short piece radiating element and the first long piece radiating element are alternately arranged along the first feed line. It is desirable that

  In all the above-mentioned inventions, it is desirable that the first radiating element and the second radiating element are oblique to the y-axis direction of the first feeding line and the second feeding line. Of course, these may be orthogonal.

  In all the above-mentioned inventions, regarding the width in the direction perpendicular to the length of the rectangular radiating antenna element, all the radiating elements may have the same width, or the width may be changed. As the width of the radiating element increases, the degree of coupling from the feeder to the radiating element increases, that is, the amount of radio wave radiation and the amount of power received increase, and this can be used to obtain a desired excitation distribution. . As a result, the directivity of the beam can be formed by the distribution characteristic of the width of the radiating element in the direction of the feed line. When the beam directivity is formed in a direction perpendicular to the antenna array plane, when attention is paid to the radiating elements arranged along one side of the feed line, the arrangement interval of the radiating elements is determined by the wavelength in the tube. An integer multiple of is good. For the radiating elements arranged on both sides of the feed line, the radiating elements arranged on the other side are preferably positioned at the midpoint of the interval between the radiating elements arranged on one side. In the plurality of array antennas, the interval between all two adjacent array antennas may be ½ or less of the free space wavelength of the radio wave used. In this case, the relationship between the azimuth angle and the phase difference output is a monovalent function, which is optimal for a phase monopulse antenna. The first connection portion and the second connection portion are portions where rectangular corners of the first radiating element and the second radiating element are connected to the first feeding line and the second feeding line. Therefore, a side parallel to the sides of the first end portion and the second end portion extends from the connection portion, and this side becomes a radio wave radiating edge.

The effects obtained by the above-described means of the present invention are as follows.
That is, the length of the first short-piece radiating element is set to ¼ of the guide wavelength λg, and the first end of the first feed line facing the first connection portion is grounded. As a result, the side of the first end portion becomes a node of a standing wave, and the side extending from the connection portion parallel to the side of the first end portion becomes a radio wave radiating edge. The electric field is on the arrangement surface of the first radiating element and is in a direction perpendicular to the radiating edge. The side of the first end located at a quarter of the guide wavelength from the connection between the first feed line and the first radiating element does not become a radiation edge of radio waves. As a result, the distance between the radiation edge of the first radiation element and the radiation edge of the second radiation element can be widened, interference can be prevented, and characteristics such as antenna directivity can be improved. .

  For example, even when the second radiating element closest to the first short-circuiting radiating element is a long piece radiating element and its end is a radiating edge of a radio wave, interference with the second radiating element is prevented. Further, if the second radiating element is a short piece radiating element, the first short piece radiating element and the second short piece radiating element are arranged so as to be closest to each other. Since the side extends from the connection portion with the feed line, the interval between the radiating edges of the radio waves becomes long. As a result, radio wave interference is effectively prevented.

  Since the radiating element has a rectangular shape, the radiating element has four sides, but two sides (a pair of sides perpendicular to the length direction) that determine the length are radiating edges of radio waves at the used frequency, and have a width. The length and width can be designed so that the two sides to be determined (a pair of sides parallel to the length direction) do not become radiation edges. The long piece radiating element has two sides that determine the length as a radiating edge of the radio wave, and the short piece radiating element has the two sides that determine the length, the side closer to the feed line as the radiating edge of the radio wave. Become.

  By making the radiation edges of these radio waves not parallel to the feed line, it is possible to generate obliquely polarized waves with respect to the road surface. As a result, when used as an antenna for an automobile radar, reception of radio waves from an oncoming vehicle can be prevented.

  According to the present invention, in the two adjacent array antennas, the first radiating element and the second radiating element that are closest to each other are at least the first radiating element constituted by the first short piece radiating element. The distance between the feed lines of the array antenna can be reduced to about ½ of the free space wavelength of the radio wave used. In addition, when the radiating element existing in the region between the first feed line and the second feed line is configured by only the first short-piece radiating element, the first radiating element and the second radiating element are each provided with the first short-piece radiating element. In the case where only the element and the second short piece radiating element are used, the interval between the feeding lines of the two adjacent array antennas can be reduced to ½ or less of the free space wavelength on each axis. As a result, in the state where the phase zeros of two adjacent array antennas are the same in the y-axis direction, the interval between the two adjacent array antennas can be made ½ or less of the free space wavelength. As a result, the relationship between the output phase difference of the array antenna and the azimuth angle in the range of −π / 2 to π / 2 becomes a monovalent function, and the azimuth of the entire range can be specified.

Plan view of a simplified local model 20 of a microstrip array antenna The graph which shows the execution result of the simulation concerning the simple model 20 Plan view of the microstrip array antenna 100 of the first embodiment. Side view of the microstrip array antenna 100 of the first embodiment. Plan view of microstrip array antenna 200 of the second embodiment. Sectional drawing which showed the earth connection mechanism of the 1st edge part of the 1st short piece radiation element in Example 2. FIG. Graph showing azimuth angle θ with respect to phase difference of array antenna 200 Plan view of microstrip array antenna 300 of Embodiment 3 Plan view of microstrip array antenna 400 of Embodiment 4 Plan view of a conventional microstrip array antenna 900 Side view of a conventional microstrip array antenna 900 Plan view of a simplified local model 10 of a microstrip array antenna The graph which shows the execution result of the simulation concerning the simple model 10 Plan view of a conventional phase monopulse antenna 800 Graph showing azimuth angle θ with respect to phase difference of phase monopulse antenna 800 Plan view of a conventional phase monopulse antenna 810

In order to quantitatively verify the interference effect between adjacent unit array antennas, assuming a simple local model (FIG. 1) of the microstrip array antenna according to the present invention, it relates to power leakage between unit array antennas. A simulation was performed. FIG. 1 shows a plan view of a simplified local model 20 of the microstrip array antenna assumed here. The local simplified model 20 includes two unit array antennas arranged in parallel in parallel, a first radiating antenna element 111a as a first radiating element, and a second radiating antenna element 121a as a second radiating element. Are taken out one by one and arranged at regular intervals. The dielectric substrate 101 has a ground plate on the back surface, and the strip line 11 as the first feed line and the strip line 21 as the second feed line are formed in parallel. The distance between the center lines of the strip lines 11 and 21 is 2.0 mm, the first radiating antenna element 111a and the second radiating antenna element 121a have a rectangular shape, and the length of the strip lines 11 and 21 is long. It is oblique to the vertical direction and is connected to the feeding strip lines 11 and 21 only in the vicinity of one vertex angle of the rectangular shape. The edges e1 and e1 constituting the first end and the second end that are not connected to the feeding strip lines 11 and 21 are short-circuited to the ground plate on the back surface. Further, the length of the first radiating antenna element 111a and the length of the second radiating antenna element 121a are λ _g / 4, respectively. Here, λ _g is the guide wavelength when the radio wave propagates through the feeding strip line 11, and the frequency of the radio wave is 76.50 GHz.

  FIG. 2 is a graph showing a simulation of the intensity at which a signal leaks out to Port 4 when a signal is input from Port 1 in the above-described local simplified model 20 of the microstrip array antenna. For example, at 76.50 GHz, the amount of power leakage from Port 1 to Port 4 is −41.40 dB, which is 10 dB or more than the simulation result (−28.48 dB) related to the conventional configuration (simple model 10) shown in FIG. Can be suppressed to a low level.

In this way, the lengths of the first radiating antenna element 111a and the second radiating antenna element 121a are λ _g / 4, and the edges e1 of the first radiating antenna element 111a and the second radiating antenna layer 121a are connected to the back surface. By short-circuiting to the ground plane, the position of the edge e1 becomes an excitation node, so that power leakage to the adjacent unit array antenna can be effectively suppressed. In this case, each edge e2 located on the opposite side to each edge e1 of the first radiating antenna element 111a and the second radiating antenna element 121a is an antinode of excitation.
As described above, according to the configuration of the present invention, interference between adjacent unit array antennas can be significantly reduced as compared with the conventional case. Alternatively, based on such an action, the distance between adjacent unit array antennas can be shortened by eliminating interference.

Hereinafter, the present invention will be described based on specific examples.
However, the embodiments of the present invention are not limited to the following examples.

  In the first embodiment, the array antenna is configured by a microstrip line. FIG. 3A is a plan view of the microstrip array antenna 100, and FIG. 3B is a side view of the microstrip array antenna 100. The microstrip array antenna 100 includes a ground plate 103 (earth) which is a ground conductor made of a metal conductor bonded to the entire surface of the dielectric substrate 101 and the back surface thereof, and a strip conductor disposed on the front side of the dielectric substrate 101. 102. The dielectric substrate 101 has a rectangular planar shape, and in the longitudinal direction (y-axis direction), a feeding strip line 11 that is a striped first feeding line that is a part of the strip conductor 102 and a second feeding line. A certain feeding strip line 21 is formed in parallel to the y-axis direction. The end portions 11 c and 21 c on the feeding point 105 side of the feeding strip lines 11 and 21 are connected to the feeding point 105 by being connected to a T-shaped connecting portion 104 which is a part of the strip conductor 102.

The structure of the unit array antenna 106 constituting the first array antenna that is a part of the strip conductor 102 is the same as the structure of the unit array antenna 107 constituting the second array antenna that is a part of the strip conductor 102. Hereinafter, the structure of the unit array antenna 106 will be described. The unit array antenna 106 is formed around a strip-shaped feeding strip line 11 having both ends 11c and 11d as both ends, and the feeding strip line 11 and nine first radiations connected thereto. It is comprised from the 1st radiation antenna elements 111a-111i which comprise an element. Five first radiating antenna elements 111a, 111b, 111c, 111d, and 111e are obliquely crossed with respect to the length direction of the feed strip line 11 at equal intervals on the outer side edge 11a of the feed strip line 11. Are connected to the feeding strip line 11. The arrangement period coincides with the guide wavelength λ _g when the radio wave having the frequency to be used propagates on the feeding strip line 11. On the other hand, four first radiating antenna elements 111f, 111g, 111h, and 111i are respectively provided on the side edge 11b inside the feed strip line 11 (region between the feed strip line 11 and the feed strip line 21). The line 11 is connected to the feeding strip line 11 at an equal interval obliquely to the length direction of the line 11. The arrangement period coincides with the above-mentioned guide wavelength λg. With this configuration, the nine first radiating antenna elements 111a to 111i are connected to the feeding strip line 11 alternately at both sides (11a, 11b) of the feeding strip line 11 with an arrangement period of λ _g / 2. Yes. The nine first radiation antenna elements 111a to 111i are all congruent and have the same structure, and the length thereof is λ _g / 4. The length is a length of a side perpendicular to the edge e, that is, a distance between a connection portion between the first radiating antenna element and the feeding strip line 11 and an end portion (edge e) facing the connection portion. The respective edges e1 of the first radiating antenna elements 111a to 111i on the side not connected to the feeding strip line 11 are short-circuited to the ground plate 103 on the back surface through via holes or the like and grounded. Each edge e2 on the side connected to the feeding strip line 11 of the first radiating antenna elements 111a to 111i is parallel to each edge e1, thereby forming the first radiating antenna elements 111a to 111i in a rectangular shape. Yes. Each edge e2 becomes a radio wave radiation element.

  The first radiating antenna elements 111a to 111i are connected to the feeding strip line 11 only in the vicinity of one vertex angle of the rectangular shape. For this reason, the first radiating antenna elements 111a to 111i are connected to the feeding strip line 11 at an inclination, but the four first radiating antenna elements 111f, 111g, 111h, and 111i existing inside are The single radiating antenna element 111a is connected and arranged in the opposite direction of 180 °, that is, in parallel. The outer five first radiating antenna elements 111a, 111b, 111c, 111d, and 111e are connected to the feeding strip line 11 in parallel with each other.

The unit array antenna 107 which is the second array antenna having the second radiating antenna elements 121a to 121i has the same structure as the unit array antenna 106. The distance dx between the center lines of the feeding strip line 11 and 21, half of the free space wavelength of the radio wave to be used, i.e., is reduced to lambda _0/2 or less. In this way, the two unit array antennas 106 and 107 can be made much closer than in the past (for example, the microstrip array antenna 900 in FIG. 8) because the edge e1 is short-circuited to the ground plate 103 and excited. And the lengths of the first radiating antenna elements 111a to 111i and the second radiating antenna elements 121a to 121i are shortened to λ _g / 4. For this reason, the unit array antenna 106 is very close to the unit array antenna 107, but interference between them is well suppressed. The first radiating antenna elements 111a to 111i constitute a first short piece radiating element, and the second radiating antenna elements 121a to 121i constitute a second short piece radiating element.

  FIG. 4-A shows a plan view of the microstrip array antenna 200 of the second embodiment. A ground plate made of a metal conductor is bonded to the entire back surface of the dielectric substrate 200. The strip conductor of the microstrip array antenna 200 includes a portion constituting the unit array antenna 206 as the first array antenna and a portion constituting the unit array antenna 207 as the second array antenna having the same structure. Become. The feeding strip line 11 constituting the first feeding line constituting the central part of the unit array antenna 206 is arranged in parallel with the feeding strip line 21 constituting the second feeding line constituting the central part of the unit array antenna 207. The direction thereof coincides with the longitudinal direction of the dielectric substrate 200.

Four first radiating antenna elements 112 a to 112 d are provided on the side 11 a inside the stripe-shaped feed strip line 11 (region between the feed strip line 11 and the feed strip line 21). In the vertical direction, they are crossed at the same angle and connected and arranged at equal intervals. The arrangement period coincides with the guide wavelength λ _g when the radio wave having the frequency to be used propagates on the feeding strip line 11. The distance between the edges e1 and e2 that are parallel to each other, that is, the lengths of the first radiation antenna elements 112a to 112d are set to λ _g / 4, respectively. Each of the first radiating antenna elements 112a to 112d is congruent with each other and is connected to the side 11a of the feeding strip line 11 only near one vertex of the rectangular shape. Each edge e1 is connected to the ground plate 103 on the back surface of the dielectric substrate 201 by a conductive via hole 109 as shown in FIG. Thereby, the edge e1 becomes the ground potential.

The structure of the unit array antenna 207 having the second radiating antenna elements 212a to 212d is the same as the structure of the unit array antenna 206 described above, and both are formed congruently. Since the lengths of the first radiating antenna elements 112a to 112d disposed between the feed strip line 11 and the feed strip line 21 are as short as λ _g / 4, the feed strip line 11 and the feed strip line 21 the distance dx between the two center lines of, it is possible to close up the lambda _0/2 or less. Even when the unit array antennas 206 and 207 are brought close to each other in this way, the edge e1 of each of the first radiating antenna elements 112a to 112d disposed between the feeding stripline 11 and the feeding stripline 21 is short-circuited. Therefore, the interference between both unit array antennas is sufficiently satisfactorily suppressed.

The graph of FIG. 5 shows the azimuth angle (arrival angle θ) of the incoming wave with respect to the phase difference of the received signal between the two unit array antennas when this microstrip array antenna 200 is used as a phase monopulse antenna. This graph is obtained by calculating a distance dx in the configuration of a microstrip array antenna 200 of the as 0.45λ _0. As described above, according to the configuration of the microstrip array antenna 200, the distance dx between the center lines of the feeding strip line 11 and the feeding strip line 21, that is, the distance dx between the phase centers of the unit array antennas is expressed as a free space wavelength. it is possible to shorten to less than half of lambda _0, by using this microstrip array antenna 200 as a phase monopulse antenna, the relationship between the phase difference and the azimuth angle θ is the azimuth angle θ is -π / 2~π In the range of / 2, it becomes a monovalent function. Therefore, the direction of the incoming wave can be known easily and reliably.

  FIG. 6 shows a plan view of the microstrip array antenna 300 of the third embodiment. The microstrip array antenna 300 includes a dielectric substrate 301, a ground plate made of a metal conductor bonded to the entire back surface thereof, and a strip conductor formed on the front side. The strip conductor on the front side constitutes a unit array antenna 306 that is a first array antenna and a unit array antenna 307 that is a second array antenna. The unit array antenna 306 and the unit array antenna 307 are congruent and have the same structure. The feeding strip line 11, which is the first feeding line constituting the central portion of the unit array antenna 306, has a stripe shape, and the longitudinal direction thereof coincides with the longitudinal direction of the dielectric substrate 301. In addition, the feeding strip line 21 that is the second feeding line constituting the central portion of the unit array antenna 307 is arranged in parallel with the feeding strip line 11.

Four first radiating antenna elements 311 a, 311 b, 311 c and 311 d are provided on the first side 11 a inside the feeding strip line 11 (region between the feeding strip line 11 and the feeding strip line 21). Are obliquely arranged at the same angle in the longitudinal direction, and are arranged at equal intervals. The arrangement period coincides with the guide wavelength λ _g when the radio wave having the frequency to be used propagates on the feeding strip line 11. The lengths of the four first radiating antenna elements 311a to 311d are λ _g / 4, respectively, and they are formed in a congruent rectangular shape. An edge e1 constituting one end of the first radiating antenna element 311a is short-circuited to a ground plate, which is a ground conductor on the back surface, via a conductive via hole or the like, and is close to the feed strip line 11 facing in parallel therewith. Only a part of the side edge e2 is connected to the first side 11a. The first radiation antenna elements 311a to 311d existing in the region between the feeding strip line 11 and the high voltage strip line 21 constitute a first short piece radiation element.

On the second side 11b outside the feed strip line 11, first radiating antenna elements 311e, 311f, 311g and 311h are obliquely crossed at the same angle in the length direction of the feed strip line 11, and are equally spaced. It is arranged. The arrangement period coincides with the guide wavelength λ _g described above. The lengths of these four first radiating antenna elements 311e to 311h are λ _g / 2. The four first radiating antenna elements 311a to 311d are connected to the feed strip line 11 in the opposite direction to the four first radiating antenna elements 311e to 311h by 180 °. These are formed in a congruent rectangular shape. Only a part of the edge eg2 of the first radiating antenna element is connected to the second side 11b. The opposite edge eg1 is an open end. The first radiating antenna elements 311e to 311h constitute a first long piece radiating element. With these arrangements, the first short-piece radiating elements 311 a, 311 b, 311 e, 311 d and the first long-piece radiating elements 311 e, 311 f, 311 g, 311 h are alternately λ _g over both sides of the feed strip line 11. The connections are arranged with a period of / 2.

The unit array antenna 306 configured around the feeding strip line 21 as the second feeding line has the same configuration. In other words, the second radiating antenna elements 312e, 312f, 312g, and 312h existing in the region between the feeding stripline 11 and the feeding stripline 21 have the edges eg1 as open ends and the length of λ _g / 2. The 2nd long piece radiation | emission element is comprised. Further, the second radiating antenna elements 312a, 312b, 312c, and 312d existing outside the feeding strip line 21 are connected to the ground conductor formed on the back surface of the dielectric substrate by the respective edges e1 by conductive via holes or the like. Thus, a second short-piece radiating element having a length of λ _g / 4 is connected to the ground.

  In the region between the feeding strip line 11 and the feeding strip line 21, the first short piece radiating elements 311 a to 311 d and the second long piece radiating elements 312 e to 312 h have their respective edges e 1. It arrange | positions closely so that it may become a position facing the edge eg1 in parallel. Also in the microstrip array antenna 300 having such a configuration, it is possible to suppress electromagnetic interference between the two while simultaneously reducing the arrangement interval between the unit array antennas (306, 307).

  FIG. 7 shows a plan view of the microstrip array antenna 400 of the fourth embodiment. This microstrip array antenna 400 has a structure similar to that of the microstrip array antenna 300 of FIG. 6, but the arrangement of the first short piece radiating elements and the first long piece radiating elements in the first radiating antenna element, and the first The arrangement order of the second short piece radiating element and the second long piece radiating element in the two radiating antenna elements is characterized.

  A unit array antenna 406 that is a first array antenna that is configured around the feed strip line 11 that is the first feed line, and a second array antenna that is configured around the feed strip line 21 that is the second feed line. The unit array antenna 407 is congruent and has the same structure. These are arranged in parallel to the front side of the dielectric substrate 401.

On the first side 11 a inside the feeding strip line 11, first short piece radiating elements 411 a and 411 c and second long piece radiating elements 411 b and 411 d are alternately connected to the feeding strip line 11 and arranged. ing. The arrangement period is the same as the guide wavelength λ _g . Further, on the second side 11b outside the feeding strip line 11, first long piece radiating elements 411e and 411g and first short piece radiating elements 411f and 411h are alternately connected to the feeding strip line 11 and arranged. Has been. The arrangement period is the same as the guide wavelength λ _g, and the first radiating antenna element disposed outside the feeding strip line 11 is the center of the interval between adjacent first radiating antenna elements disposed inside. It is arranged.

The unit array antenna 407, which is the second array antenna, has the same configuration. That is, the second long piece radiating elements 412e and 412g and the second short piece radiating elements 412f and 412h are alternately connected to the feed strip line 21 on the first side 21b inside the feed strip line 21. It is arranged. The arrangement period is the same as the guide wavelength λ _g . Further, on the second side 21 a outside the feeding strip line 21, second short piece radiating elements 412 a and 412 c and second long piece radiating elements 412 b and 412 d are alternately connected to the feeding strip line 21 and arranged. Has been. The arrangement period is the same as the guide wavelength λ _g, and the second radiating antenna element disposed outside the feeding strip line 21 is the center of the interval between adjacent second radiating antenna elements disposed inside. It is arranged.

  In the region between the feed strip line 11 and the feed strip line 21, the first short piece radiating elements 411a and 411c and the second long piece radiating elements 412e and 412g have their respective edges e1 and their respective pieces. The edges eg1 are arranged close to each other so as to be opposed to each other in parallel. In addition, the first long piece radiating elements 411b and 411d and the second short piece radiating elements 412f and 412h are close to each other so that their respective edges e1 and their respective edges eg1 are parallel to each other. Arranged.

Also in the microstrip array antenna 400 having such a configuration, it is possible to suppress electromagnetic interference between the two while simultaneously reducing the arrangement interval between the unit array antennas (406, 407).

[Other variations]
The embodiment of the present invention is not limited to the above-described embodiment, and other modifications as exemplified below may be made. Even with such modifications and applications, the effects of the present invention can be obtained based on the functions of the present invention.
(Modification 1)
For example, in each of the above embodiments, the width of the radiating antenna element is made uniform, but it is desirable to adjust the width of each radiating antenna element according to the desired directivity. According to such an adjusted setting, the width of each radiating antenna element is determined in accordance with the excitation amplitude at each arrangement position corresponding to the desired directivity. Directional characteristics can be effectively realized.

(Modification 2)
Further, it is more desirable to connect an appropriate absorption resistor or a matched antenna element to the terminal end of the unit array antenna. This can reduce unwanted unwanted reflections at the end of the unit array antenna.

(Modification 3)
In each of the above embodiments, the configuration in which two unit array antennas are arranged is shown, but the number of unit array antennas arranged in parallel may be arbitrary.

  The present invention provides a suitable configuration for a phase monopulse antenna, but can also be applied to more general microstrip array antennas, ie, antennas that handle other microwaves such as, for example, FMCW radar.

DESCRIPTION OF SYMBOLS 100: Microstrip array antenna 101: Dielectric board | substrate 102: Strip conductor 103: Grounding plate 104: Connection part 105: Feeding point 11,21: Feeding strip line 111a-111i, 112a-112d, 311a-311h, 411a-411h: 1st radiation antenna element 121a-121i, 212a-212d, 312a-312h, 412a-412h: 2nd radiation antenna element 111a-111i, 112a-112d: 1st short piece radiation element 121a-121i, 212a-212d: 2nd short piece Radiating elements 311a to 311d, 411a, 411c, 411f, 411h: first short piece radiating elements 311e to 311h, 411b, 411d, 411e, 411g: first long piece radiating elements 312a to 312d, 412a, 412c, 412f, 412h: second short piece radiating elements 312e to 312h, 412b, 412d, 412e, 412g: second long piece radiating elements

Claims (8)

A microstrip array antenna in which a feed line and a radiating element are formed by a strip conductor on the surface of a dielectric substrate having a ground conductor on the back side, along a first feed line extending linearly in the y-axis direction A plurality of rectangular second radiating elements are separated along a first array antenna in which a plurality of rectangular first radiating elements are spaced apart from each other, and a second feed line extending linearly in the y-axis direction. In the array antenna device, in which at least two array antennas with the second array antenna disposed in parallel are spaced apart in the x-axis direction perpendicular to the y-axis direction and disposed in parallel.
The first radiating element disposed in a region between the first feed line and the second feed line has a first connection portion connected to the first feed line and a side facing the first connection portion. The first end is connected to the ground conductor, and the length between the first end and the first end is connected to the ground conductor. An array antenna apparatus comprising the first short piece radiating element formed.   2. The array antenna apparatus according to claim 1, wherein only the first short piece radiating element is disposed in a region between the first feed line and the second feed line.   The second radiating element disposed in a region between the first feed line and the second feed line has a second connection portion connected to the second feed line and a side facing the second connection portion. The length between the second end and the second end is a quarter of the guide wavelength of the radio wave propagating through the second feed line at a predetermined operating frequency, and the second end is connected to the ground conductor. The array antenna apparatus according to claim 1, wherein the array antenna apparatus is configured by the second short piece radiating element.   The second radiating element disposed in a region between the first feed line and the second feed line is opposed to the second connection portion connected to the second feed line and the second connection portion. The length between the second end portion on the side is a half of the guide wavelength of the radio wave propagating through the second feed line at a predetermined operating frequency, and the second end portion is an open end. The array antenna apparatus according to claim 1, wherein the array antenna apparatus includes a second long piece radiating element. A microstrip array antenna in which a feed line and a radiating element are formed by a strip conductor on the surface of a dielectric substrate having a ground conductor on the back side, along a first feed line extending linearly in the y-axis direction A plurality of rectangular second radiating elements are separated along a first array antenna in which a plurality of rectangular first radiating elements are spaced apart from each other, and a second feed line extending linearly in the y-axis direction. In the array antenna device, in which at least two array antennas with the second array antenna disposed in parallel are spaced apart in the x-axis direction perpendicular to the y-axis direction and disposed in parallel.
The first radiating element disposed in a region between the first feed line and the second feed line includes a first connection part connected to the first feed line and a side facing the first connection part. The first end is connected to the ground conductor, and the length between the first end and the first end is connected to the ground conductor. A first short-piece radiating element,
The length between the first connection portion and the first end portion is a half length of the guide wavelength of the radio wave propagating through the first feed line at a predetermined operating frequency, and the first end portion is The first long piece radiating element that is an open end and a mixture along the y-axis direction,
The second radiating element disposed in a region between the first feed line and the second feed line includes a second connection portion connected to the second feed line and a side facing the second connection portion. The length between the second end and the second end is a quarter of the guide wavelength of the radio wave propagating through the second feed line at a predetermined operating frequency, and the second end is connected to the ground conductor. A second short piece radiating element formed;
The length between the second connection portion and the second end portion is ½ the guide wavelength of the radio wave propagating through the second feed line at a predetermined operating frequency, and the second end portion is And the second long piece radiating element which is an open end and a mixture along the y-axis direction,
The second long piece radiating element is disposed at a position where the second end portion faces the first end portion of the first short piece radiating element,
The second short piece radiating element is disposed at a position where the second end portion faces the first end portion of the first long piece radiating element.   6. The array antenna apparatus according to claim 5, wherein the first short piece radiating elements and the first long piece radiating elements are alternately arranged along the first feed line.   The interval between two array antennas adjacent to each other in the plurality of array antennas is ½ or less of a free space wavelength of a radio wave to be used. Array antenna device.   8. The device according to claim 1, wherein the first radiating element and the second radiating element are oblique to the y-axis direction of the first feed line and the second feed line. 9. The array antenna device according to claim 1.

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