JPWO2011125087A1 - antenna - Google Patents

Abstract

Provided is a more versatile antenna that can be provided with an arbitrary number of feeding points and can be used for each radar apparatus that performs measurement by various methods. An antenna composed of a line disposed on a printed circuit board, which is arranged at an arbitrary interval in the left-right direction and has a plurality of first power distribution circuits having a symmetrical shape, and adjacent first power distribution circuits A plurality of second power distribution circuits having a symmetrical shape, a power supply line connected to the left and right midpoints of at least one of the two or more first power distribution circuits, And an antenna element connected to the power distribution circuit.

Description

  The present invention relates to an antenna device, and more particularly to an antenna device used in a radar that detects an object by transmitting and receiving electromagnetic waves.

  In recent years, an electromagnetic wave has been radiated, and a reflected wave reflected by the object has been received. Based on the emitted electromagnetic wave and the received reflected wave, the relative distance to the object, the relative velocity, and the object A radar apparatus that measures the direction in which an object exists has been put into practical use. Various antennas have been proposed for use as receiving antennas for receiving reflected waves in such radar devices. As an example of such an antenna, there is a microstrip array antenna described in Patent Document 1 (hereinafter referred to as conventional technology).

  In the prior art, four rows of unit array antennas are arranged in parallel in the left-right direction and connected to two feeding points. When connecting a four-row unit array antenna and two feeding points, in the prior art, a two-row unit array antenna arranged in the center is connected to the two feeding points, respectively, and the remaining two outside the two feeding points are connected to the outside. Each of the arranged unit array antennas is connected to each of two feeding points. That is, in the conventional technique, two unit array antennas in the center of the four rows of unit array antennas are shared by two feeding points, and three unit array antennas are connected to each of the two feeding points.

  Thus, in the prior art, although each is a combined array antenna composed of three unit array antennas, by sharing the two central unit array antennas, the distance between the left and right directions of the combined array antennas is reduced, The phase interval between the combined array antennas can be reduced. By adopting such a microstrip array antenna according to the prior art in a radar apparatus that measures the direction in which an object exists, for example, by a phase monopulse method, the phase interval of reflected waves received by the combined array antennas is ± 180. It is possible to perform measurement without causing a so-called phase wraparound in which an accurate phase interval cannot be detected by shifting by more than 0 °.

JP 2009-076986 A

  However, the above prior art has the following problems. That is, in recent years, a radar apparatus that improves measurement accuracy using three antennas, or a radar apparatus that performs digital beam scanning using a plurality of antennas has been developed. However, since the above-mentioned conventional technology can provide only two feeding points, it cannot be used for such radar devices.

  Accordingly, an object of the present invention is to provide a more versatile antenna that can have an arbitrary number of feeding points and can be used in a radar apparatus that performs detection by various methods.

  In order to achieve the above object, the present invention has the following characteristics.

  1st aspect of this invention is the antenna which consists of a track | line arrange | positioned on a dielectric substrate, Comprising: The 1st power distribution circuit which is arrange | positioned at arbitrary intervals in the left-right direction, and has a left-right symmetric shape And a left and right midpoint of at least one of a plurality of second power distribution circuits that are arranged to connect adjacent first power distribution circuits and have a symmetrical shape, and two or more first power distribution circuits. And an antenna element connected to the second power distribution circuit.

  According to a second aspect of the present invention, in the first aspect, the first power distribution circuit has the same upper and lower line lengths across the contact point with the second power distribution circuit.

  According to a third aspect of the present invention, in the second aspect, the first power distribution circuit has a ring shape.

  In a fourth aspect of the present invention, in the third aspect, the center interval between adjacent antenna elements is half the wavelength when signals transmitted and received by the antenna elements propagate in the air.

  In a fifth aspect of the present invention based on the fourth aspect, the second power distribution circuit has a ring shape.

  According to the present invention, an arbitrary number of feeding points can be provided, and a highly versatile antenna that can be used in a radar apparatus that performs detection by various methods can be provided.

FIG. 1 is a diagram showing an example of the configuration of an antenna according to the present invention. FIG. 2A is a diagram showing an example of a first ring circuit according to the present invention. FIG. 2B is a diagram showing an example of a first ring circuit according to the present invention. FIG. 3 is a diagram showing an example of a second ring circuit according to the present invention. FIG. 4 is a diagram showing an example of the excitation amplitude distribution of the antenna according to the present invention. FIG. 5 is a diagram showing an example of the excitation amplitude distribution of the antenna according to the present invention. FIG. 6A is a diagram illustrating an example of the width of the first ring-type circuit. FIG. 6B is a diagram illustrating an example of the width of the first ring-type circuit. FIG. 7 is a diagram illustrating an example of a configuration of an antenna according to the present invention including a termination circuit. FIG. 8 is a diagram illustrating an example of a configuration of an antenna according to the present invention including a termination circuit. FIG. 9 is a diagram illustrating an example of a configuration of an antenna according to the present invention including a termination circuit. FIG. 10 is a diagram illustrating another example of the first ring-type circuit.

(First embodiment)
FIG. 1 is a diagram illustrating an example of a configuration of an antenna according to the present embodiment. In the present embodiment, a feeding point 101, a first feeding line 102, a first ring-type circuit 103, a second ring-type circuit 104, and a second The antenna 1 is configured by forming the components of the feeder line 105 and the antenna element 106 on the copper foil of the dielectric substrate. Since it is well known that the antenna 1 has the same transmission and reception characteristics, in the description of the present embodiment, the case where the antenna 1 is used as a transmission antenna will be described as an example for ease of explanation. To do. In the description of this embodiment, it is assumed that the antenna 1 is mounted on the vehicle, the direction from the feeding point 101 toward the first ring circuit 103 is perpendicular to the horizontal plane, and the direction is the direction of the vehicle. It demonstrates as what is mounted so that it may face upward. Further, FIG. 1 shows a downward direction and a left-right direction based on the upward direction of the vehicle. In the description of the present invention, as shown in FIG. 1, the left-right direction for explanation and the left-right direction on the paper are interchanged.

  As shown in FIG. 1, the antenna 1 according to the present embodiment is configured by connecting a plurality of components of the feed point 101 to the antenna element 106 in the left-right direction.

  2A and 2B are enlarged views showing only the first ring circuit 103 in the antenna 1 shown in FIG. As shown in FIG. 2A, the first ring-type circuit 103 is a track configured by connecting a pair of semicircular lines arranged in the vertical direction and a pair of linear lines arranged in the left-right direction. A closed circuit having a shape, which includes a first power supply port A and a first power supply port B on its side surface, and one of the first power supply port A and the first power supply port B is changed to the other. Power can be transmitted to

  Moreover, as shown in FIG. 2B as an example, any one or more first ring circuits 103 constituting the antenna 1 according to this embodiment may be provided with a first power supply port C on the lower side. . The first ring-type circuit 103 according to the present embodiment is bilaterally symmetric as is apparent from the above description. The first power supply port C, the first power supply port A, and the first power supply port B are symmetrical. The line length to each of the is the same. Therefore, by providing the first power supply port C as shown in FIG. 2B to the first ring circuit 103 according to the present embodiment, the first power supply port A and the first power supply port B are provided. The signals can be distributed from the first power supply port C so that the phases of the signals in each of the first power supply port C are in phase. FIG. 1 shows an example of an antenna 1 in which a first feeding port C is provided in a first ring circuit 103 located in the center in the left-right direction and on both sides thereof.

  When the first power supply port C is provided in the first ring-type circuit 103, as is apparent from FIG. 1, the first power supply port C is preceded by the first power supply port C. Signals can be input and output at the feeding point 101 located.

  FIG. 3 is an enlarged view showing only the second ring circuit 104 in the antenna 1 shown in FIG. As shown in FIG. 3, the second ring-type circuit 104 is a closed circuit composed of a line having a hollow circular shape, and includes a second power supply port A on the right side thereof and a second power supply on the left side thereof. A port B is provided, a second power supply port C is provided on the upper side, and an open stub is provided on the lower side. As is clear from FIG. 1, the antenna element 106 is connected to the tip of the second power supply port C via the second power supply line 105.

  The above is the description of the first ring type circuit 103 and the second ring type circuit 104 according to the present embodiment. As shown in FIG. 1, the antenna 1 according to the present embodiment is arranged so that the first ring circuits 103 having the shape described above are arranged at equal intervals, and the first ring circuits 103 are connected. The second ring type circuit 104 is arranged in the configuration.

  In the above description, the first ring-type circuit 103 and the second ring-type circuit 104 according to this embodiment each have a power supply port having a length as shown in FIGS. 2A to 3. As explained. However, when the antenna 1 is configured by the first ring circuit 103 and the second ring circuit 104 according to the present embodiment, the ring shape of each ring circuit is shown as an example in FIG. (In this embodiment, the first ring-type circuit 103 has a track shape and the second ring-type circuit 104 has a hollow circle shape). Shall be composed.

  In addition, the antenna 1 according to the present embodiment includes the first ring-type circuit 103 arranged as shown in FIG. One power supply port C is provided, and antenna elements 106 are provided in the second power supply ports C of the second ring circuit 104, respectively. Hereinafter, the description of the antenna 1 configured as shown in FIG. 1 will be continued.

  FIG. 4 is a diagram illustrating an example of an excitation amplitude distribution when a signal is supplied and transmitted to the feeding point 101 located at the center in the left-right direction of the antenna 1 according to the present embodiment. The horizontal axis in FIG. 4 indicates the numbers assigned to the antenna elements 106 of the antenna 1 according to this embodiment as shown in FIG. Further, the vertical axis in FIG. 4 indicates the excitation amplitude of the antenna element 106 of the antenna 1 corresponding to the number indicated on the horizontal axis.

  Further, in FIG. 4, the highest excitation amplitude among the antenna elements 106 constituting the antenna 1 is 1, and the ratio of the excitation amplitude of the other antenna elements 106 to the highest excitation amplitude is shown for each antenna element 106. The excitation amplitude indicated by a negative value in the excitation amplitude distribution shown in FIG. 4 is that the signal transmitted from the antenna element 106 corresponding to the excitation amplitude is from the antenna element 106 corresponding to the excitation amplitude indicating a positive value. It shows that the phase is shifted by 180 ° with respect to the transmitted signal. Therefore, if the phase is not considered, the excitation amplitude distribution shown in FIG. 4 is from the antenna element 106 closest to the center in the left-right direction of the antenna 1 (in the example shown in FIG. 4, the antenna elements # 4 and # 5). The distribution becomes such that the excitation amplitude decreases in order as it moves away in the left-right direction.

  In order to explain the reason why the excitation amplitude distribution of the antenna 1 according to the present embodiment is as shown in FIG. 4, first, a case where a signal propagates through the first ring circuit 103 will be described. In the first ring circuit 103 according to the present embodiment, for example, the length (line length) of the track-shaped line width center line (two-dot chain line in FIG. 2A or FIG. 2B) is 2λg. Designed. Here, λg is the wavelength of the signal when the signal propagates through the line constituting the antenna 1. In the first ring circuit 103 according to the present embodiment, as described above, the first power supply port A and the first power supply port B are provided on the track-shaped side surfaces with the line length of 2λg, respectively. And, for example, the signal propagating from the first power supply port A to the first power supply port B includes the upper semicircular line direction and the lower semicircular line direction in the track shape shown in FIG. 2A. Distributed to. As shown in FIG. 2A, the track-shaped first ring circuit 103 is vertically symmetric, and therefore, from the first feeding port A, the upper semicircular line direction and the lower semicircular line direction The signals distributed to and propagate through the lines having a line length of λg (length corresponding to one wavelength) and reach the first power supply port B. The same applies to the case where a signal propagates from the first power supply port B to the first power supply port A.

  As described above, in the first ring circuit 103 according to the present embodiment, when a signal propagates from one of the first power supply port A and the first power supply port B to the other, a length corresponding to one wavelength is obtained. Therefore, the phases of the propagation ports are in phase with each other.

  Next, a case where a signal propagates through the second ring circuit 104 will be described. As an example, in the second ring circuit 104 according to the present embodiment, the circumferential length (line length) of the hollow circular line width center line (two-dot chain line in FIG. 3) is the above-described λg. Designed to be In the second ring circuit 104 according to the present embodiment, as described above, the second power supply port A and the second power supply port B are provided on the hollow circular side surfaces having the line length λg, respectively. Yes. For example, a signal propagating from the second power supply port A to the second power supply port B is distributed to the upper semicircular line and the lower semicircular line in the circular shape shown in FIG. Is done. In the second ring circuit 104, the signal distributed in the upper semicircular shape from the second power supply port A is further distributed to the second power supply port C and the second power supply port B. Accordingly, the signal distributed from the second power supply port A to the upper semicircular shape and propagating to the second power supply port B is reduced in intensity and reduced in amplitude by the amount distributed to the second power supply port C. To do. In addition, since the second ring circuit 104 according to the present embodiment has a line length of λg as described above, the second ring circuit 104 is distributed from the second power supply port A to the upper semicircular shape, so that the second power supply port B The signal propagating up to is propagated through the line length of λg / 2.

  On the other hand, in the second ring circuit 104, the signal distributed in the lower semicircular shape from the second power supply port A propagates to the second power supply port B through the open stub. Here, the second ring circuit 104 is designed so that the line length is λg as described above. Furthermore, the open stub is designed so that the line length is λg / 4. Then, the signal distributed in the lower semicircular shape from the second power supply port A propagates through the lower semicircular shape to the open stub (propagating the line length of λg / 4), and reciprocates through the open stub ( After propagating the line length of λg / 2), the lower semicircular shape is propagated to the second feeding port B (propagating the line length of λg / 4). Therefore, in the second ring circuit 104 according to the present embodiment, when the signal is distributed from the second feeding port A to the lower semicircular shape and propagates to the second feeding port B, the line of λg Will propagate the length.

  Then, in the second ring circuit 104 according to the present embodiment, the signals distributed from the second power supply port A into the upper and lower semicircular shapes are combined at the second power supply port B. At this time, as described above, in the second power supply port B, the signal whose amplitude has been reduced by propagation through the line length of λg / 2 and the signal which has been propagated through the line length of λg are combined. That is, when a signal propagates through the second ring circuit 104 from the second power supply port A to the second power supply port B, the second power supply port B is out of phase with each other by a half wavelength and has different amplitudes. The signal is synthesized. Therefore, when a signal propagates through the second ring circuit 104 from the second power supply port A to the second power supply port B, the signals at the second power supply port B cancel each other out of signals having different amplitudes. Therefore, the signal has a reduced amplitude. This is because the second ring circuit 104 according to the present embodiment has a symmetrical shape as shown in FIG. 3, so that a signal is transmitted from the second power supply port B to the second power supply port A. The same applies when propagating.

  That is, in the second ring circuit 104 according to the present embodiment, when a signal propagates from one of the second power supply port A and the second power supply port B to the other, As a result, the amplitude decreases. Hereinafter, in the second ring circuit 104, the ratio between the amplitude of the signal at the propagation power supply port and the amplitude of the signal at the propagation power supply port is referred to as a distribution ratio.

  As is apparent from FIG. 1, the signal supplied to the feeding point 101 located at the center in the left-right direction of the antenna 1 alternately propagates through the first ring circuit 103 and the second ring circuit 104, The signals are distributed to the antenna elements 106 and transmitted from the respective antenna elements 106. As described above, the signal alternately propagating through the first ring circuit 103 and the second ring circuit 104 depends on the distribution ratio of the second ring circuit 104 as described above. As a result, the amplitude decreases. Therefore, the excitation amplitude distribution of the antenna 1 according to the present embodiment has an antenna element 106 (in the example shown in FIG. 4, # 4, And # 5 antenna element 106), the distribution is such that the excitation amplitude decreases in the order of antenna element 106 farthest from antenna element 106 (# 1 and # 8 in the example shown in FIG. 4).

  In the antenna 1 according to the present embodiment, the signal supplied to the feeding point 101 located at the center in the left-right direction is branched by the first ring circuit 103, which is also located at the center in the left-right direction, and left-right direction Propagate to each. A signal branched leftward from the first ring circuit 103 located at the center in the left-right direction of the antenna 1 alternates between the first ring circuit 103 and the second ring circuit 104 as described above. Are transmitted in the order of the antenna element 106 of # 5 to the antenna element 106 of # 8. On the other hand, a signal branched rightward from the first ring-type circuit 103 located at the center of the left-right direction of the antenna 1 alternates between the first ring-type circuit 103 and the second ring-type circuit 104 as described above. Are transmitted in the order of the antenna element 106 of # 4 to the antenna element 106 of # 1.

  Here, as shown in FIG. 4, the antenna elements 106 of # 5 to # 8 that transmit a signal branched leftward from the first ring circuit 103 located at the center in the left-right direction of the antenna 1 are adjacent to each other. The antenna elements 106 are 180 ° out of phase with each other. Similarly, the antenna elements 106 of # 4 to # 1 that transmit a signal branched in the right direction from the first ring circuit 103 located at the center in the left-right direction of the antenna 1 are adjacent to each other as shown in FIG. The antenna elements 106 are 180 ° out of phase with each other. Hereinafter, this reason will be described.

  The phase difference between the adjacent antenna elements 106 by 180 ° is attributed to the respective line lengths of the first ring circuit 103 and the second ring circuit 104 that connect the adjacent antenna elements 106. That is, for example, the second ring circuit connected to the # 7 antenna element 106 from the second feed port C of the second ring circuit 104 connected to the # 6 antenna element 106 of FIG. The line length up to the second power supply port C 104 is 1.5λg.

  More specifically, the line length from the second feeding port C to the second feeding port B of the second ring circuit 104 connected to the # 6 antenna element 106 is λg / 4. The second power feeding port B of the second ring circuit 104 connected to the # 6 antenna element 106 and the second power feeding port B of the second ring circuit 104 connected to the # 7 antenna element 106. The line length when the signal propagates from the first power supply port A to the first power supply port B through the first ring circuit 103 connected to the port A is λg as described above. Then, the second power feed port A of the second ring circuit 104 connected to the # 7 antenna element 106 connected to the first power feed port B of the first ring circuit 103 is used as the second power feed. The line length to port C is λg / 4.

  That is, a signal distributed to adjacent antenna elements 106, such as a signal distributed to # 6 antenna element 106 and a signal distributed to # 7 antenna element 106, has a line length of 1.5λg. Since it is distributed to the adjacent antenna element 106 after propagating, it is out of phase with each other by a half wavelength. Therefore, the signals transmitted from the adjacent antenna elements 106 existing in the right direction from the first ring circuit 103 located at the center of the antenna 1 change in phase by 180 °. The same applies to signals transmitted from the respective adjacent antenna elements 106 existing in the left direction from the first ring circuit 103 located at the center of the antenna 1.

  As described above, in the antenna 1 according to the present embodiment, the signal distributed from the first power supply port C of the first ring circuit 103 to the first power supply port A and the first power supply port B propagates in phase. Will be. Further, in the antenna 1 according to the present embodiment, when the signal propagates through the second ring circuit 104 to the left and right circuits, the amplitude is relatively reduced at the power feeding port of the propagation destination. Furthermore, in the antenna 1 according to the present embodiment, a signal branched rightward from the first ring circuit 103 located at the center in the left-right direction is an adjacent antenna element 106 (antenna elements 106 to # 1 of # 4). The phase is inverted between the elements 106), and the signal branched in the left direction is inverted in phase between the adjacent antenna elements 106 (# 5 antenna elements 106 to # 8 antenna elements 106). For this reason, the excitation amplitude distribution of the antenna 1 according to the present embodiment is as shown in FIG.

  In the above description, the excitation amplitude distribution when a signal is supplied to the feeding point 101 located at the center in the left-right direction of the antenna 1 has been described. On the other hand, when a signal is supplied from the feeding point 101 to the first ring type circuit 103 provided with the first feeding port C in addition to the first ring type circuit 103 located at the center in the left-right direction of the antenna 1, As shown as an example in FIG. 5, the excitation amplitude distribution is symmetric with respect to the feeding point 101 to which the signal is supplied as the center in the left-right direction. The excitation amplitude distribution Dis1 shown in FIG. 5 is the excitation amplitude distribution shown in FIG. 4 and is an excitation amplitude distribution when a signal is supplied to the feeding point 101 located at the center of the antenna 1 in the left-right direction. Further, the excitation amplitude distribution Dis2 shown in FIG. 5 is an excitation amplitude distribution when a signal is supplied to the first feeding point 101 existing in the right direction from the center of the antenna 1 in the left-right direction. Also, the excitation amplitude distribution Dis3 shown in FIG. 5 is an excitation amplitude distribution when a signal is supplied to the first feeding point 101 existing in the left direction from the center in the left-right direction of the antenna 1. As shown as an example in FIG. 5, according to the antenna 1 according to the present embodiment, the excitation amplitude distribution can be shifted in the left-right direction according to the position of the feeding point 101 that supplies the signal. In the excitation amplitude distribution Dis2 shown in FIG. 5, the illustration of the excitation amplitude of the # 8 antenna element 106 is omitted. Furthermore, in the excitation amplitude distribution Dis3 shown in FIG. 5, the illustration of the excitation amplitude of the antenna element 106 of # 1 is omitted.

  In the above description, the antenna 1 is used as a transmission antenna, and the excitation amplitude distribution has been mainly described. On the other hand, even if the antenna 1 is used as a receiving antenna, it goes without saying that the excitation amplitude distribution is the same as that described above.

  Further, in the antenna 1 according to the present invention, by adjusting the width in the left-right direction of the first ring circuit 103, the distance in the left-right direction of the adjacent antenna elements 106 can be adjusted to an arbitrary distance. With reference to FIG. 6A to FIG. 6B, it will be described in more detail with respect to making the space between the adjacent antenna elements 106 in the left-right direction arbitrary. FIG. 6A is a diagram showing an example of the first ring circuit 103 having a relatively narrow width H and the spacing HA in the left-right direction of the antenna element 106, and FIG. It is a figure which shows an example of the space | interval HA of the left-right direction of the ring type circuit 103 and the antenna element 106. FIG. As shown in FIGS. 6A and 6B as an example, the antenna 1 according to the present invention has a width H of the first ring-type circuit 103 so that the horizontal interval HA between adjacent antenna elements 106 is an arbitrary interval. Can be determined. However, when the width H of the first ring circuit 103 is determined in order to set the horizontal distance HA of the antenna element 106 to an arbitrary distance, the second power feeding port of the adjacent second ring circuit 104 is determined. It is necessary to determine the length V in the front-rear direction of the first ring circuit 103 so that the line length connecting the Cs becomes 1.5λg. As shown as an example in FIGS. 6A and 6B, in order to increase the width H of the first ring circuit 103 in order to increase the horizontal interval HA between the adjacent antenna elements 106, the same FIG. As shown as an example in FIG. 6B, the length V in the front-rear direction of the first ring circuit 103 must be relatively shortened.

  Thus, in the antenna 1 according to the present invention, the distance between the adjacent antenna elements 106 in the left-right direction can be set arbitrarily. Here, for example, if the distance between the adjacent antenna elements 106 in the left-right direction is 0.5λ, the antenna 1 according to the present invention can be used as a receiving antenna of a phase monopulse radar device, thereby It is possible to prevent a so-called phase wraparound in which an accurate phase interval cannot be detected when the phase interval of the received signal is shifted by ± 180 ° or more. Here, λ is a wavelength in the atmosphere. It goes without saying that the spacing between the antenna elements 106 does not have to be exactly 0.5λ.

  In order to prevent the occurrence of phase folding as described above in the above-described prior art, at least two antennas with a small width capable of setting the horizontal spacing of the antenna elements 106 to 0.5λ are arranged side by side in the horizontal direction. There is a need to. However, since such a narrow antenna has a wide beam width, an unnecessary signal may be received, resulting in erroneous detection or degradation in detection performance. On the other hand, in the antenna 1 according to the present invention, not only 2 but also 3 or more antenna elements 106 can be used. By using a well-known method, the beam can be shaped to have a necessary detection angle width. Here, the detection angle width is a range in which the radar apparatus using the antenna 1 according to the present invention can measure the relative distance to the object, the relative speed, the direction (angle) in which the object exists, and the like. Typically, it has a fan shape centered on the position of the antenna of the radar device, and it means the breadth of the angle of the fan shape.

  Further, in the above description, the antenna 1 provided with one antenna element 106 for each of the second feeders 105 has been described. However, in another embodiment, the shape of the antenna element 106 constituting the antenna 1 according to the present invention may be any shape. An array antenna composed of a plurality of elements may be used.

  As shown in FIG. 1, when only a part of the first ring type circuits 103 have the first power supply port C, the first ring type circuit 103 with the first power supply port C is provided. Depending on the position, the arrangement of the left and right first feeding ports C may be asymmetric, and the symmetry of the excitation amplitude distribution may be impaired. In order to prevent the symmetry of the excitation amplitude distribution generated in this way from being lost, as shown in FIG. 7, the first ring circuit 103 to which the receiving circuit is not connected has a termination for matching. A circuit may be connected.

  For example, in the antenna 1 having the configuration shown in FIG. 1, a signal supplied from the feeding point 101 or a signal received by the antenna element 106 is reflected in the first ring circuit 103 located at both ends in the left-right direction. In some cases, characteristics such as the excitation amplitude distribution of the antenna 1 may be degraded. In order to prevent the characteristics of the antenna 1 from deteriorating due to such signal reflection, matching is made with the first ring circuit 103 located at both ends of the antenna 1 in the left-right direction as shown as an example in FIG. It is recommended to connect a termination circuit for taking

  In order to maintain the symmetry of the excitation amplitude distribution as described above and to prevent the characteristics of the antenna 1 from deteriorating due to the reflection of the signal as described above, as shown in FIG. Even if both a termination circuit for matching at the feeding point 101 that is not connected and a termination circuit for matching at the first ring circuit 103 positioned at both ends of the antenna 1 in the left-right direction are connected. Good.

  In addition, the first ring circuit 103 according to the first embodiment has a track shape as described above. However, in another embodiment, the shape of the first ring circuit 103 may be a geometric shape such as a perfect circle shape, or a shape obtained by flattening these shapes.

  The length of the first ring circuit 103 according to the first embodiment is such that the line length connecting the second power feeding ports C of the adjacent second ring circuits 104 is 1.5λ. It was decided to decide. However, in another embodiment, the lengths of the lines constituting the first ring circuit 103 so that the lengths of the second power supply ports C of the adjacent second ring circuits 104 are arbitrary. The phase of the signal in the adjacent antenna element 106 may be shifted by 180 °.

  The length of the first ring circuit 103 according to the first embodiment is such that the signal propagates from one of the first power supply port A and the first power supply port B to the other. The line length was set to 2λg so as to be in phase with each other at the previous feeding port. However, in another embodiment, the line length of the first ring circuit 103 is changed so that a phase difference is generated between the signals at the first power supply port A and the first power supply port B. Also good.

  In the present embodiment, the first ring circuit 103 is used as an example of the first power distribution circuit described in the claims. However, the shape of the first power distribution circuit described in the claims is not limited to the ring-shaped track shape. As the first power distribution circuit described in the claims, a U-shaped circuit may be used as shown in FIG. 10 as an example. Further, similarly to the first ring circuit 103 according to the present embodiment, the first power supply port C may be provided in the U-shaped circuit shown as an example in FIG.

  Moreover, in this embodiment, the 2nd ring type circuit 104 shall be used as an example of the 2nd power distribution circuit as described in a claim. However, in the second power distribution circuit described in the claims, the signal propagates from one of the second power feeding port A and the second power feeding port B to the other, so that in the propagation power feeding port Any circuit may be used as long as the amplitude of the signal is an arbitrarily small amplitude, and the circuit is not limited to a hollow circle having an open stub.

  Further, in the antenna 1 according to the first embodiment, the first ring circuit 103 is formed in a track shape with a line length of 2λg so as to obtain the excitation amplitude distribution shown as an example in FIG. The circuit 104 has a circular shape with a line length of λg. However, the excitation amplitude distribution of the antenna according to another embodiment is not limited to the distribution shown in FIG. 4, and the first ring-type circuit 103 and the second ring amplitude circuit so as to obtain an arbitrary excitation amplitude distribution. Each shape of the ring-type circuit 104 and the line length may be determined.

  Further, in the antenna 1 according to the first embodiment, as shown in FIG. 1 as an example, all adjacent antenna elements 106 are arranged at equal intervals in the left-right direction. However, in the antenna according to another embodiment, it is not necessary to make the intervals between all adjacent antenna elements 106 equal. For example, as described above, all or a part of all the adjacent antenna elements 106 may be arranged at intervals different from other intervals so that an arbitrary excitation amplitude distribution can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, a highly versatile antenna can be provided, for example, it is useful for the antenna etc. which are used with the radar apparatus mounted in moving bodies, such as a motor vehicle.

DESCRIPTION OF SYMBOLS 1 Antenna 101 Feeding point 102 1st feed line 103 1st ring type circuit 104 2nd ring type circuit 105 2nd feed line 106 Antenna element

Further, in the antenna 1 according to the present invention, by adjusting the width in the left-right direction of the first ring circuit 103, the distance in the left-right direction of the adjacent antenna elements 106 can be adjusted to an arbitrary distance. With reference to FIG. 6A to FIG. 6B, it will be described in more detail with respect to making the space between the adjacent antenna elements 106 in the left-right direction arbitrary. FIG. 6A is a diagram showing an example of the first ring circuit 103 having a relatively narrow width H and the spacing HA in the left-right direction of the antenna element 106, and FIG. It is a figure which shows an example of the space | interval HA of the left-right direction of the ring type circuit 103 and the antenna element 106. FIG. As shown in FIGS. 6A and 6B as an example, the antenna 1 according to the present invention has a width H of the first ring-type circuit 103 so that the horizontal interval HA between adjacent antenna elements 106 is an arbitrary interval. Can be determined. However, when the width H of the first ring circuit 103 is determined in order to set the horizontal distance HA of the antenna element 106 to an arbitrary distance, the second power feeding port of the adjacent second ring circuit 104 is determined. It is necessary to determine the length V in the vertical direction of the first ring circuit 103 so that the line length connecting Cs becomes 1.5λg. As shown as an example in FIGS. 6A and 6B, in order to increase the width H of the first ring circuit 103 in order to increase the horizontal interval HA between the adjacent antenna elements 106, the same FIG. As shown as an example in FIG. 6B, the vertical length V of the first ring circuit 103 must be relatively shortened.

Claims (5)

An antenna composed of a line arranged on a dielectric substrate,
A plurality of first power distribution circuits which are arranged at arbitrary intervals in the left-right direction and have a symmetrical shape;
A plurality of second power distribution circuits arranged to connect adjacent first power distribution circuits and having a symmetrical shape;
A feed line connected to the left and right midpoints of at least any one of the two or more first power distribution circuits;
And an antenna element connected to the second power distribution circuit.   2. The antenna according to claim 1, wherein the first power distribution circuit has the same upper and lower line lengths across the contact point with the second power distribution circuit.   The antenna according to claim 2, wherein the first power distribution circuit has a ring shape.   The antenna according to claim 3, wherein a distance between centers of adjacent antenna elements is half of a wavelength when a signal transmitted and received by each antenna element propagates in the air.   The antenna according to claim 4, wherein the second power distribution circuit has a ring shape.

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