Micro stripline array antenna

Abstract

Micro stripline array antenna (1, 10, 40, 50) with a dielectric substrate (12) on the back of which a conductive grounding plate (11) is formed, and a stripline (13) formed on the dielectric substrate (12), wherein the strip conductor (13) comprises a feed strip line (3, 15, 43, 51) which is linear and extends in a predetermined direction of extension, and at least two radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a - 5d; 21a - 21v; 41a - 41c) of a predetermined length, wherein at least one of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a - 5d; 21a - 21v; 41a - 41c) is connected to one side of the feed strip line (3, 15, 43, 51) and at least one of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a - 5d; 21a - 21v; 41a - 41c) is connected to the other side of the feed line (3, 15, 43, 51), the longitudinal directions of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a- 5d; 21a - 21v; 41a - 41c) are parallel to each other and are arranged at an angle other than 90° with respect to the direction of extension, the feed line (3, 15, 43, 51) has a partially or completely curved shape and extends completely in the direction of extension, so that the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a - 5d; 21a - 21v; 41a - 41c) are connected to the feed line (3, 15, 43, 51) at the same angle, and each of the sides of the feed line (3, 15, 43, 51) is connected to a plurality of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a- 5d; 21a - 21v; 41a - 41c), characterized by the fact that the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a- 5d; 21a - 21v; 41a - 41c) which are connected to one side of the feed line (3, 15, 43, 51), are connected to areas of the feed line which correspond to the middle areas between adjacent two of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a- 5d; 21a - 21v; 41a - 41c) which are connected to the other side of the feed line (3, 15, 43, 51).

Description

GENERAL STATE OF THE ART (Technical field of the invention)

[0001] The present invention relates to a micro-stripline array antenna using a dielectric substrate. (Related state of the art)

[0002] A micro stripline array antenna, which incorporates a stripline formed on a dielectric substrate, offers advantages in thinness, low manufacturing costs, and productivity. Due to these characteristics, micro stripline array antennas are widely used as transmitting and receiving antennas for various radio wave receivers, such as vehicle radar used, for example, in anti-collision systems and adaptive cruise control (ACC).

[0003] A well-known example of a previously described micro-stripline array antenna is a micro-stripline array antenna in which a plurality of radiating antenna elements are connected and arranged at predetermined intervals along the two sides of a linearly arranged feed stripline (supply stripline).

[0004] When the micro-strip-line array antenna, as described above, is installed in a vehicle, for example for automotive radar, the feed line is typically positioned perpendicular to the ground so that the antenna can achieve a desired radiation pattern (particularly a radiation pattern in the vertical direction). Linear polarization, inclined at a predetermined angle to the ground (for example, 45°), is preferably used as the radio wave transmitted / received by the micro-strip-line array antenna to avoid interference with a radiated wave from an oncoming vehicle.

[0005] Accordingly, for example, a micro-stripwire array antenna is proposed in JP 2001-44752A. In this micro-stripwire array antenna, while the entire antenna is arranged vertically, radiating antenna elements are connected to and arranged along the sides of the feed stripwire, such that the radiating antenna elements are inclined with respect to the longitudinal direction of the feed stripwire in order to achieve linear polarization with an inclination relative to the ground.

[0006] JP H11-251 833 A discloses a micro-strip-line array antenna with a dielectric substrate on the rear side of which a conductive grounding plate is formed, and a strip-line formed on the dielectric substrate, wherein the strip-line comprises a feed line which is linear and extends in a predetermined direction of extension, and at least two radiating antenna elements of a predetermined length, wherein at least one of the radiating antenna elements is connected to one side of the feed line and at least one of the radiating antenna elements is connected to the other side of the feed line, the longitudinal directions of the radiating antenna elements are parallel to each other and are arranged at an angle other than 90° with respect to the direction of extension, the feed line has a partially or completely curved shape and extends completely in the direction of extension.so that the radiating antenna elements are connected to the feed line at the same angle, and each side of the feed line is connected to a plurality of the radiating antenna elements.

[0007] US Patent 8 058 998 B2 discloses an RFID antenna with an elongated structure consisting along an axis long compared to the signal wavelength, comprising two ribbon-like feed lines of electrically conductive material, the feed lines lying in a common plane and spaced evenly apart laterally, and a plurality of radiating interference branch conductors associated with the feed lines at multiple locations spaced apart along the feed lines.

[0008] US Patent 5,859,616 A discloses a nested planar array antenna system comprising an array of parallel rows of transmitting dipole element pairs and an array of parallel rows of receiving dipole element pairs, the two arrays being nested. Each dipole element pair comprises a first dipole element and a second dipole element adjacent to and orthogonal to the first dipole element. All first dipole elements are parallel to each other, and all second dipole elements are parallel to each other. All dipole elements are located on the same surface, and on another surface parallel to and spaced apart from the first surface is an array of transmitting feed pairs and an array of receiving feed pairs, the arrays being nested together. SUMMARY OF THE INVENTION

[0009] The present invention was made with regard to previously known circumstances, and one object of the present invention is to provide a micro-stripline array antenna in which a linear polarization, the direction of which is inclined at a predetermined angle with respect to a feed line, and radiating antenna elements on both sides of the feed line exhibit an approximately symmetrical directional characteristic. This object is achieved by a micro-stripline array antenna having the features of claim 1 and claim 2, respectively. The dependent claims are directed to advantageous embodiments of the invention.

[0010] The micro stripline array antenna according to the invention comprises a dielectric substrate, on the rear side of which a conductive grounding plate is formed, and a stripline formed on the dielectric substrate, wherein the stripline comprises a feed line which is linear and extends in a predetermined direction of extension, and comprises at least two radiating antenna elements of a predetermined length, wherein at least one of the radiating antenna elements is connected to one side of the feed line and at least one of the radiating antenna elements is connected to the other side of the feed line, the longitudinal directions of the radiating antenna elements are arranged parallel to each other and at an angle other than 90° with respect to the direction of extension, and the feed line has a partially or completely curved shape and extends completely along the direction of extension.so that the radiating antenna elements are connected to the feed line at the same angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The attached drawings show: Fig. 1 A representation of an arrangement of a conventional micro-stripline array antenna; Fig. 2 a horizontal plane radiation pattern of a conventional micro-stripline array antenna designed for automotive radar; Fig. 3A a representation of a property of a single radiating antenna element forming the conventional micro-stripguide array antenna and a representation of an arrangement of a right-hand radiating antenna element; Fig. 3B a representation of an arrangement of a left-side radiating antenna element; Fig. 3C a radiation pattern of the horizontal plane of the radiating antenna elements; Fig. 4 a representation of a simple arrangement of a micro-stripline array antenna according to one embodiment; Fig. 5A a representation of a property of a single radiating antenna element and a representation of a relationship between a right-hand radiating antenna element and a left-hand radiating antenna element; Fig. 5B a radiation pattern of the horizontal plane of the individual radiating antenna element; Fig. 6A a top view of a specific arrangement of a micro stripline array antenna according to another embodiment; Fig. 6B a sectional view along a line AA in Fig. 6A; Fig. 7 a radiation pattern of the horizontal plane of the micro-stripline array antenna according to the embodiment for an automotive radar; Fig. 8A shows a representation of another example of the micro-stripline array antenna; and Fig. Figure 8B shows another example of the micro-stripline array antenna. DETAILED DESCRIPTION OF PREFERRED EXECUTION FORMS

[0012] Preferred embodiments of the present invention are explained below with reference to the drawings.

[0013] Fig. Figure 1 shows an example of a micro-stripline array antenna in which radiating antenna elements are connected to and arranged along the feed line, the radiating antenna elements being inclined with respect to the longitudinal direction of the feed line. A micro-stripline array antenna 100, as shown in Fig. Figure 1 shows that a strip conductor 103 is formed on a dielectric substrate 102. A conductive grounding plate 101 is formed on the back side of the dielectric substrate 102.

[0014] The strip conductor 103 comprises as its main components a linearly arranged feed strip line 105, a plurality of radiating antenna elements 111a, 111b, 111c, 111d, 111e, ..., which are connected to one side of the feed strip line 105, and a plurality of radiating antenna elements 112a, 112b, 112c, 112d, 112e, ..., which are connected to the other side of the feed strip line 105.

[0015] The radiating antenna elements 111a to 111e, ..., 112a to 112e, ... are connected to the two sides of the feed line 105 such that they are parallel to each other. In this case, the longitudinal directions of the radiating antenna elements are at an angle of 45° to the longitudinal direction of the feed line 105. According to the arrangement described above, the micro-stripline array antenna can transmit / receive linearly polarized waves whose direction is inclined at an angle of 45° to the longitudinal direction of the feed line 105.

[0016] However, if a majority of the micro stripline array antennas are 100, as they are in Fig. As shown in 1, the sensors are mounted in the horizontal direction to form an automotive radar (hereinafter also referred to as automotive radar array) that produces the desired radiation, the sidelobes in the radiation pattern of the automotive radar array increase.

[0017] Fig. Figure 2 shows an example of a radiation pattern (horizontal plane radiation pattern) of the micro-stripline array antenna 100 for the automotive radar arrangement. As shown in Fig. As shown in Figure 2, the radiation pattern of the micro-strip-line array antenna 100 with the automotive radar configuration does not exhibit symmetry of the sidelobes with respect to the main lobe. One of the sidelobes exceeds a specification value (upper limit) required for the sidelobes of a micro-strip-line array antenna for automotive radar.

[0018] As previously described, if the micro stripline array antenna 100 is used as an automotive radar and the level of the unnecessary side lobe increases and exceeds the specification value, this can lead to various problems such as the appearance of ghost images.

[0019] To solve these problems, the inventors of the present application have, in various ways, explained the reason for the increase in the level of the side lobe in the horizontal plane radiation pattern for the formation of the conventional micro-stripline array antenna 100 according to Fig. 1 for an automotive radar. The main cause was found to be that the connection angles of the radiating antenna elements with respect to the feed line 105 (in other words, power supply branch angles between the feed line 105 and the radiating antenna elements) differ between the two sides of the feed line 105.

[0020] That means, with the conventional micro-stripline array antenna 100, as in Fig. As shown in Figure 3A, the radiating antenna elements 111a and the like (which are hereinafter also referred to as right-hand radiating antenna elements) are connected to one side of the feed line 105 at an angle of 45° with respect to the longitudinal direction of the feed line 105 (i.e., the power supply direction). However, as shown in Fig. Figure 3B shows the radiating antenna elements 112a and the like (hereinafter also referred to as left-side radiating antenna elements) connected to the other side of the feeder line 105 at an angle of 135° with respect to the longitudinal direction of the feeder line 105.

[0021] If the connection angles of the radiating antenna elements with respect to the feed line 105 (power supply branch angle) differ between the right-hand radiating antenna element and the left-hand radiating antenna element, the directional characteristic of the individual right-hand radiating antenna elements and the individual left-hand radiating antenna elements has an asymmetric characteristic as shown in Fig. 3C is shown. Additionally, the peak levels at which the amplification (antenna gain) is at its maximum differ only slightly.

[0022] As in Fig. As shown in Figure 1, the micro-stripline array antenna 100 is formed by arranging the right-hand and left-hand radiating antenna elements, whose radiation characteristics are asymmetrical to each other, in the vertical direction. The micro-stripline array antenna 100 is designed for an automotive radar. In this case, as shown in Figure 1, the antenna is configured as follows: Fig. As shown in Figure 2, the radiation pattern of the micro-stripline array antenna shows 100 right and left sidelobes that are asymmetrical, and the level of the unnecessary sidelobes increases and can exceed a specification value. (1) A basic arrangement of a micro-stripline array antenna

[0023] Fig. Figure 4 shows a representation of a micro-stripline array antenna according to an embodiment of the present invention. A micro-stripline array antenna 1, as described in Fig. Figure 4 shows that a strip conductor is formed on a dielectric substrate. A conductive grounding plate is formed on the back side of the dielectric substrate. Fig. Figure 4 shows only the stripline with the most characteristic arrangement on the micro-stripline array antenna 1. First, the arrangement of the stripline on the micro-stripline array antenna 1 is shown in relation to Fig. 4 explained.

[0024] As in Fig. As shown in Figure 4, the stripline of the micro-stripline array antenna 1 includes a feed stripline 3 and a plurality of radiating antenna elements 5a, 5b, 5c, 5d, ..., 6a, 6b, 6c, 6d, ..., which are the main components. The feed stripline 3 extends in a predetermined direction (in Fig. 4 downwards). The radiating antenna elements 5a, 5b, 5c, 5d, ..., 6a, 6b, 6c, 6d, ... are connected to the two sides of the feed line 3 and arranged along them.

[0025] The feeder line 3 has a continuous serpentine shape, such as an S-shape, and extends entirely in the direction of its extension. That is, if a straight line parallel to the direction of extension is defined as an imaginary straight line 8, the feeder line 3 extends along the imaginary straight line 8 in a uniform S-shape.

[0026] The strip-shaped radiating antenna elements 5a, 5b, 5c, 5d, ... are connected to (or protrude from) a first side 3a, which is one of the two sides of the feed line 3. The strip-shaped radiating antenna elements 6a, 6b, 6c, 6d, ... are connected to (or protrude from) a second side 3b, which is the other of the two sides of the feed line 3.

[0027] Next, using the radiating antenna element 5a as an example, arrangements of the radiating antenna elements 5a, 5b, 5c, 5d, ..., which are connected to the first side 3a, are described. The length L of the radiating antenna element 5a (the distance between the contact point with the feed line 3 and a field emission edge line 55a, which is an open end) is approximately half a wavelength λg (i.e., approximately λg / 2) of a radio wave propagating through the stripline (hereinafter also referred to as the "inline wavelength λg").

[0028] The radiating antenna element 5a is arranged at an angle of 45° with respect to the direction of extension (imaginary straight line 8) and is connected to the feed line 3 at an angle of 90°.

[0029] This means that, since the feed line 3 has a serpentine shape, such as an S-shape, the direction of a line varies locally along the S-shape. The radiating antenna element 5a is connected to the S-shaped feed line 3 such that an angle of 45° with respect to the direction of the line is formed at the connection point. That is, the radiating antenna element 5a protrudes from the connection area of ​​the feed line 3 in such a way that it extends in the direction normal to the line.

[0030] Furthermore, the field emission edge line 55a (which is orthogonal to the field emission direction of a radiated radio wave), which is one side of an outline of the radiating antenna element 5a, is parallel to the direction of the strip line 3 at the connection area. The field emission edge line 55a is at an angle of 45° with respect to the direction of extension (imaginary straight line 8).

[0031] The radiating antenna elements 5b, 5c, 5d, ..., which are connected to the first side 3a, have essentially the same arrangement as the radiating antenna element 5a described above. Each of the radiating antenna elements 5b, 5c, 5d, ... has a length L of λg / 2. Each of the radiating antenna elements 5b, 5c, 5d, ... is arranged such that it is at an angle of 45° with respect to the direction of extension and is connected to the feed line 3 such that it is at an angle of 90° with respect to it.

[0032] The distance d between the respective radiating antenna elements 5a, 5b, 5c, 5d, ..., which are connected along the first side 3a, corresponds to the inline wavelength λg. That is, the strip-shaped radiating antenna elements are arranged along the first side 3a at the same distance d as the inline wavelength λg and are connected to it. Since the radiating antenna elements 5a, 5b, 5c, 5d, ... are located at an angle of 45° with respect to the direction of extension, as described above, the longitudinal directions of the radiating antenna elements 5a, 5b, 5c, 5d, ... are parallel to each other.

[0033] Next, using antenna element 6a as an example, arrangements of the radiating antenna elements 6a, 6b, 6c, 6c, ..., which are connected to the second side 3b, are described. The radiating antenna element 6a is basically designed like the radiating antenna element 5a, which is connected to the first side. The radiating antenna element 6a has a length L of λg / 2. The radiating antenna element 6a is arranged at an angle of 45° with respect to its direction of extension (imaginary straight line 8) and is connected to the feed line 3 at an angle of 90°. That is, the radiating antenna element 6a protrudes from the connection area of ​​the feed line 3 in such a way that it extends in the direction normal to the line.

[0034] Additionally, the field emission edge line 65a, which is one side of an outline edge line of the radiating antenna element 6a, is parallel to the direction of the feed line 3 in the connection area. The field emission edge line 65a is at an angle of 45° with respect to the direction of extension (imaginary straight line 8).

[0035] The radiating antenna elements 6b, 6c, 6d, ..., which are connected to the second side 3b, are arranged in the same way as the radiating antenna elements described previously. Each of the radiating antenna elements 6b, 6c, 6d, ... has a length L of λg / 2. Each of the radiating antenna elements 6b, 6c, 6d, ... is arranged such that it is at an angle of 45° with respect to the direction of extension and is connected to the feed line 3 at an angle of 90°.

[0036] The distance d between the respective radiating antenna elements 6a, 6b, 6c, 6d, ..., which are connected along the second side 3b, corresponds to the inline wavelength λg. That is, the strip-shaped radiating antenna elements are arranged along the second side 3b at the same distance d as the inline wavelength λg and are connected to it. Since, as described above, the radiating antenna elements 6a, 6b, 6c, 6d, ... are located at an angle of 45° with respect to the direction of extension, the longitudinal directions of the radiating antenna elements 6a, 6b, 6c, 6d, ... which are connected to the second side 3b are parallel to each other. The longitudinal directions of the radiating antenna elements 6a, 6b, 6c, 6d, ... are parallel to those of the radiating antenna elements 5a, 5b, 5c, 5d, ....

[0037] The radiating antenna elements 6a, 6b, 6c, 6d, ..., which are arranged along the second side 3b, are connected to areas corresponding to the middle areas between adjacent two of the radiating antenna elements 5a, 5b, 5c, 5d, ..., which are arranged along the first side 3a. In particular, as shown in Fig. As shown in Figure 4, the radiating antenna element 6a, which is part of the radiating antenna elements connected to the second side 3b and is located closest to the power supply side, is connected to a region corresponding to an intermediate area between the radiating antenna elements 5a and 5b connected to the first side 3a. That is, the radiating antenna element 6a is connected to a region corresponding to an intermediate area of ​​a path between a connection point of radiating antenna element 5a and a connection point of radiating antenna element 5b. Other radiating antenna elements are connected in the same way.

[0038] Consequently, the radiating antenna elements are alternately connected to two sides of the feed line 3 at regular intervals and arranged along these.

[0039] If the micro-stripline array antenna 1 is configured as described above, when electrical energy is applied to the input terminal (the upper side in Fig. 4) is provided, which extends towards the end (the lower side in Fig. 4) As the electrical energy propagates, portions of it are successively fed into the radiating antenna elements connected to sides 3a and 3b of the feed line 3 and are radiated by these elements. The remaining portion of the electrical energy propagates towards the termination. As a result, the electrical energy propagating through the feed line 3 progressively weakens towards the termination.

[0040] Additionally, since the longitudinal directions of the radiating antenna elements are parallel to each other, all the field emission directions of the radiated radio waves are the same (parallel to each other). This means that all the radiating antenna elements emit radio waves whose polarization planes of the main polarization components are parallel to each other. The planes of polarization (field emission directions) are inclined at an angle of 45° with respect to the direction of extension of the feed line 3. Thus, when using the micro-stripline array antenna 1, which is arranged so that its direction of extension is perpendicular to the ground, radio waves can be transmitted / received whose polarization plane is at an angle of 45° with respect to the ground.

[0041] Meanwhile, the widths W of the radiating antenna elements 5a, 5b, 5c, 5d, ..., 6a, 6b, 6c, 6d, ... are determined starting from the input connection for electrical power (the upper side in Fig. 4) continuously increasing. This means that the width W of the radiating antenna element closest to the input terminal is the smallest, and the width W of the radiating antenna element closest to the termination (the lower side in Fig. 4) is located, which is the largest.

[0042] As previously described, as an example of the present embodiment, the width W of the radiating antenna element varies depending on the connection position with the feed line 3 in order to equalize radiation amounts from the radiating antenna elements.

[0043] To equalize the radiation levels from the radiating antenna elements, it is necessary to reduce the width W and the interconnection ratio of the radiating antenna element located closer to the input terminal, where a large amount of electrical energy propagates through the feed line 3. Conversely, it is necessary to increase the width W and the interconnection ratio of the radiating antenna elements located closer to the termination terminal, where less electrical energy propagates through the feed line 3.

[0044] It should be noted that the matching of the radiation levels from the radiating antenna elements is described as an example. The widths W of the radiating antenna elements are precisely determined according to various specifications, characteristics, or the like required for the micro-stripline array antenna 1.

[0045] This means that the excitation amplitudes to be achieved in the radiating antenna elements are determined beforehand according to the radiation pattern required for the micro-stripline array antenna 1. Thus, the widths W of the radiating antenna elements are determined in order to exhibit propagation patterns corresponding to the desired excitation amplitudes. (2) Properties of the radiating antenna elements

[0046] Next, the properties of the radiating antenna elements 5a, 5b, 5c, 5d, ..., 6a, 6b, 6c, 6d, ..., which form the micro-stripline array antenna 1, are described using the example of a single element with reference to the Fig. 5A and Fig. 5B explained. Based on Fig. Section 5 explains a property of the radiating antenna elements 5a, 5b, 5c, 5d, ... (hereinafter also referred to as right-hand radiating antenna elements), which are connected to the first side 3a, one of the two sides of the feed line 3, using the example of radiating antenna element 5a for a single element. Meanwhile, a property of the radiating antenna elements 6a, 6b, 6c, 6d, ... (hereinafter also referred to as left-hand radiating antenna elements), which are connected to the second side 3b, is explained using the example of radiating antenna element 6a for a single element.

[0047] In the micro-stripline array antenna 1, the longitudinal direction of the right-hand radiating antenna element 5a and the longitudinal direction of the left-hand radiating antenna element 6a are parallel to each other. The right-hand radiating antenna element 5a and the left-hand radiating antenna element 6a are connected to the feed line 3 at the same angle (90° in this embodiment).

[0048] In the conventional micro stripline array antenna, as used in Fig. 3A and Fig. As shown in Figure 3B, the power supply branch angle with respect to the feed stripline differs between the right-hand radiating antenna element and the left-hand radiating antenna element. However, in the micro stripline array antenna 1 of the present embodiment, as shown in Fig. 4 and Fig. 5A shows that each part of the electrical energy supplied at the input terminal of the feed line 3 and propagating along the feed line 3 is discharged at the coupling area (coupled area) of the radiating antenna element at the same power supply branch angle, which is 90°.

[0049] Consequently, the radiation patterns (radiation patterns in the horizontal plane) of the individual right-hand radiating antenna element 5a and the individual left-hand radiating antenna element 6a, as shown in Fig. Figure 5B shows mirror-symmetrical properties. Additionally, peak levels, at which maximum gains occur, largely coincide. (3) A specific arrangement of a micro-stripline array antenna

[0050] Next, a specific arrangement of a micro-stripline array antenna of an embodiment according to the present invention will be described with reference to Fig. 6A and Fig. 6B explained. Fig. Figure 6A shows a top view of a micro stripline array antenna 10. Fig. 6B is a cross-sectional view along a line AA in Fig. 6A. The micro stripline array antenna 10, as shown in Fig. Figure 6A shows a strip conductor 13 formed on a dielectric substrate 12. A conductive grounding plate 11 is formed on the back side of the dielectric substrate 12.

[0051] The stripline 13 includes a feed line 15 and a plurality of radiating antenna elements 21a to 21v, 22a to 22v, which constitute the main components. The feed line 15 extends in a predetermined direction. The radiating antenna elements 21a to 21v and 22a to 22v are connected to and arranged along the two sides of the feed line 15.

[0052] When electrical energy supplied at the input terminal of the feed line 15 propagates towards the termination end, portions of the electrical energy are successively coupled into the radiating antenna elements 21a to 21v and 22a to 22v, which are connected to the two ends of the feed line 15, and radiated from them. The remaining components of the electrical energy propagate towards the termination end.

[0053] A stripline antenna element 17 for effectively radiating the residual energy is arranged at the termination of the feed stripline 15. It should be noted that a matching network for absorbing the residual energy can be arranged at the termination instead of the stripline antenna element 17. The design of the termination of the feed stripline 15 can be precisely determined.

[0054] The feed line 15 has a uniform serpentine shape, such as an S-shape, and extends in the direction of extension like the feed line 3 of the micro-stripline array antenna 1, shown in Fig. 4.

[0055] The radiating antenna elements 21a to 21v are connected to a first side 15a, which is one of the two sides of the feed line 15, and are arranged at a distance from each other corresponding to the wavelength λg of a radio wave propagating through the feed line 15. Similarly, the radiating antenna elements 22a to 22v are connected to a second side 15b, which is the other of the two sides of the feed line 15, and are arranged at a distance from each other corresponding to the wavelength λg.

[0056] The shapes and arrangements of the radiating antenna elements of the micro-stripline array antenna 10 are fundamentally the same as those of the micro-stripline array antenna 1, which is described in Fig. Figure 4 shows that the length of the elements is λg / 2 and the longitudinal directions of the radiating antenna elements are parallel to each other and are at an angle of 45° to the direction of extension. Additionally, the radiating antenna elements are connected to the feed line 15 at an angle of 90°. Furthermore, the widths of the radiating antenna elements increase continuously from the input connection for electrical power to the termination to adjust the radiation levels from the radiating antenna elements.

[0057] It should be noted that in the micro stripline array antenna 10, a predetermined number of the radiating antenna elements, belonging to radiating antenna elements 21a to 21v and 22a to 22v and located near the termination side, have rectangular shapes. One corner of each radiating antenna element is connected to the feed stripline 15. Specifically, nine radiating antenna elements 21k to 21v, located at the termination side and connected to the first side 15a, and nine radiating antenna elements 22k to 22v, located at the termination side and connected to the second side 15b, have rectangular shapes. One corner of each of the radiating antenna elements 21k to 21v and 22k to 22v is connected to the feed stripline 15.

[0058] In the micro-stripline array antenna 10 of the embodiment as described in Fig. As shown in Figure 6A, the radiating antenna element closer to the end face has a greater width. If the element's width is large, a radio wave emitted by the radiating antenna element will contain, in addition to the main polarization components (which are parallel to the longitudinal direction of the radiating antenna element and at an angle of 45° to the direction of propagation), a large number of unnecessary cross-polarization components that intersect the main polarization components.

[0059] To solve this problem, considering the wider radiating antenna elements, one corner of each is connected to the feed line 15 in such a way as to reduce the size of the connection area with the feed line 15. Consequently, the generation of unnecessary cross-polarization components is avoided.

[0060] Fig. Figure 7 shows a horizontal plane radiation pattern of the micro-stripline array antenna 10, which is in Fig. Figure 6 is shown and is configured as described above. In this case, a plurality of micro-stripline array antennas 10 are arranged horizontally in an array to form, for example, an automotive radar that achieves the desired radiation pattern (automotive radar array). As shown in Fig. As shown in Figure 7, the horizontal plane radiation pattern of the micro-stripline array antenna 10 meets a specification in which the difference between a main lobe and a side lobe is 30 dB or more. The side lobes exhibit symmetry. Gain values ​​of the side lobes are limited to be sufficiently lower than the specified value (upper limit). Consequently, the radiation pattern of the individual right-hand radiating antenna element and the individual left-hand radiating antenna element (horizontal plane radiation pattern) is realized with a mirror-symmetric property. (4) Advantages of the embodiment

[0061] In the micro-stripline array antenna of the embodiment described above, the radiating antenna elements are arranged at an angle of 45° to the direction of extension of the feed line. The radiating antenna elements are configured such that each connection angle (power supply branch angle) with respect to the feed line is 90°. In particular, the feed line extends completely in the direction of extension and has a uniform serpentine shape, such as an S-shape. Consequently, connections between the feed line and each of the radiating antenna elements are realized at the same angle.

[0062] As previously described, since all radiating antenna elements are arranged on both sides of the feed line (right-side radiating antenna elements and left-side radiating antenna elements) and are connected to the feed line at the same angle (or substantially an equivalent angle), a radiation pattern of the individual right-side radiating antenna element and the individual left-side radiating antenna element can be realized, which, as in Fig. 5B is shown, exhibiting mirror symmetry.

[0063] Consequently, this embodiment of the micro-stripline array antenna enables linear polarization, the direction of which is inclined at a predefined angle (45° in this embodiment) relative to the direction of the feed line. Furthermore, an excellent radiation pattern can be achieved in which unnecessary sidelobes are suppressed.

[0064] Furthermore, the feed line has an S-shape. The radiating antenna elements are connected to the feed line at a 90° angle (right angle). This simplifies the shape of the feed line compared to a case where the radiating antenna elements are connected at an angle greater than 90°. In other words, the configuration where the radiating antenna elements are connected at a 90° angle can be implemented more easily.

[0065] Furthermore, the feed line has no bent corners and a completely uniform shape. This prevents the radiation of unnecessary electrical energy through the feed line, resulting in a more efficient micro-stripline array antenna.

[0066] Furthermore, a majority of the radiating antenna elements are connected to the sides of the feed line at a predetermined distance d (in this embodiment, the inline wavelength λg). This creates a so-called series-fed micro-stripline array antenna. This allows for a more efficient micro-stripline array antenna that limits the loss of supplied electrical energy and with which a desired radiation pattern (according to Fig. 7) can be achieved. (Variations)

[0067] It should be noted that the present invention is not limited to the embodiments described above, but any modification, variation or equivalence that appears obvious to the person skilled in the art should fall within the scope of the present invention.

[0068] In the case of the micro-stripline array antenna 1, as described in Fig. As shown in Figure 4, the feeder line 3, as an example, exhibits an absolutely uniform and continuous S-shape. For example, as shown in Figure 4, the feeder line 3 can have a perfectly uniform and continuous S-shape. Fig. Figure 8A shows a micro stripline array antenna 40 designed to have a feed stripline 43 with a sawtooth shape.

[0069] The micro stripline array antenna 40 comprises the feed stripline 43, which has a sawtooth shape and extends along the direction of extension, and radiating antenna elements 41a, 41b, 41c, ..., 42a, 42b, 42c, ..., which are connected to two sides of the feed stripline 43 and are arranged along these two sides at a predefined angle (for example, 90°).

[0070] As with the micro stripline array antennas that are in Fig. 4 and Fig. 6A, can be explained by the previously described and in Fig. The micro-stripline array antenna shown in Figure 8A can be implemented with linear polarization, the direction of which is inclined at a predetermined angle (e.g., 45°) with respect to the direction of propagation of the feed line 43. Furthermore, an excellent radiation pattern can be achieved in which unnecessary sidelobes are suppressed.

[0071] It should be noted that the feed line 43 of the micro stripline array antenna 40, as shown in Fig. Figure 8A shows curved sections with angled corners. This increases the loss of electrical energy at the angled corners, which can reduce the efficiency of the entire antenna.

[0072] To solve this problem, as in Fig. As shown in Figure 8B, it is advantageous that a feed line 51 of a micro-stripline array antenna 50 has a uniform shape around the curved regions. Consequently, since the curved regions have no angular corners, it is possible to avoid unnecessary radiation of electrical energy from the curved regions.

[0073] The preceding embodiments ( Fig. 4A and Fig. 6A) and Fig. 8A and Fig. Figure 8B shows micro-stripline array antennas whose feedline has a continuous S-shape or a sawtooth shape. However, the feedline does not necessarily always have shapes that vary continuously and regularly, but also shapes that are irregularly bent.

[0074] This means that as long as the feed line as a whole extends in a predefined direction and all the radiating antenna elements are connected at the same angle when viewed locally, the shape of the bend in the feed line is not limited in any special way.

[0075] Furthermore, in the embodiment described above, the distance between the respective radiating antenna elements connected to the two sides is approximately λg / 2, for example. The distance between the radiating antenna elements can be precisely determined. For example, based on λg, the distance can be determined such that it is shorter (or longer) than λg, depending on the connection positions of the feed line 3 or depending on a connection between the radiating antenna elements.

[0076] In the embodiment described above, the radiating antenna elements 6a, 6b, 6c, 6d, ..., arranged along the second side 3b, are connected to regions corresponding to the mid-ranges between adjacent two radiating antenna elements 5a, 5b, 5c, 5d, ..., arranged along the first side. By way of example, the radiating antenna elements arranged along one side are connected to regions corresponding to the mid-ranges between adjacent two radiating antenna elements arranged along the other side. The spatial relationship between the radiating antenna elements arranged along one side and the radiating antenna elements arranged along the other side can be precisely determined.

[0077] Furthermore, a radiating antenna element can be connected to either side of the feed line. This means that the number of radiating antenna elements is unlimited.

[0078] As an example, in the embodiment described above, the longitudinal directions of the radiating antenna elements are at an angle of 45° to the direction of extension of the feed line. The angle at which the radiating antenna elements are arranged relative to the direction of extension can be precisely determined, except in cases where the longitudinal directions are parallel or perpendicular to the direction of extension.

[0079] Furthermore, as an example, the radiating antenna elements are connected to the feed line at an angle of 90°. The radiating antenna elements can be connected at an angle other than 90°.

[0080] In the preceding embodiments, the direction of extension of the feed line is defined as a specified direction (longitudinal direction of the imaginary straight line 8). However, the direction of extension is not necessarily the specified direction. That is, the imaginary line 8 need not be a straight line, but can be a line with a partially or completely curved shape. Even in this case, the feed line extends entirely along the curved imaginary line (in the direction of extension) and is completely or partially curved. Due to its shape, all radiating antenna elements can be connected at the same angle as in the previous case.

[0081] The following summarizes aspects of the previously described embodiments.

[0082] To solve the problems described above, the inventors of the present application have taken into account that the connection angles with respect to the feed line of the radiating antenna elements are the same on both sides. That is, the present invention is created by taking into account that electrical energy is supplied to the radiating antenna elements of both sides at the same angle with respect to the energy supply direction.

[0083] To solve the problems described above, the present invention provides, as one aspect, a micro-strip-line array antenna comprising a dielectric substrate on the rear side of which a conductive grounding plate is formed, and a strip-line formed on the dielectric substrate, wherein the strip-line includes a feed line which is linear and extends in a predetermined direction, and at least two radiating antenna elements of a predetermined length, wherein at least one of the radiating antenna elements is connected to one side of the feed line and at least one of the radiating antenna elements is connected to the other side of the feed line, the longitudinal directions of the radiating antenna elements are parallel to each other and are arranged at an angle other than 90° with respect to the direction of extension.and the feed line has a partially or completely curved shape and extends entirely in the direction of extension, so that the radiating antenna elements are connected to the power supply strip line at the same angle.

[0084] In the micro-stripline array antenna designed as described above, the feed line does not have a straight shape, unlike the conventional micro-stripline array antenna as described in Fig. The micro-stripline array antenna is not depicted in Figure 1, but has a partially or completely curved shape. It should be noted that although the micro-stripline array antenna appears to have a partially curved shape, it extends entirely in the direction of its predetermined extension.

[0085] The feed line is bent, as described above, so that all the radiating antenna elements are arranged along the two sides of the feed line and are connected to the feed line at an equivalent angle.

[0086] This means that as long as the feed line is completely straight, there is a difference of 100 in the case of the conventional micro-stripline array antenna, as used in Fig. As shown in Figure 1, the right-hand radiating antenna element is separated from the left-hand radiating antenna element by a connecting angle of 180°.

[0087] To solve the problem described above, the feed line is partially or completely bent while extending entirely in the predetermined direction of extension. Consequently, the radiating antenna elements are connected to the feed line at the same angle.

[0088] According to the micro-stripline array antenna designed as described above, the longitudinal directions of the radiating antenna elements are parallel to each other and are oriented at an angle other than 90° to the direction of the feed line. Additionally, the radiating antenna elements are connected to both sides of the feed line at the same angle. This allows, when the linear polarization, whose direction is inclined at a predetermined angle to the feed line, to be achieved, radiation patterns of the individual right-hand and left-hand radiating antenna elements that exhibit approximately mirror-symmetric properties.

[0089] In the micro stripline array antenna, the radiating antenna elements are connected to the feed line at an angle of 90°.

[0090] If the radiating antenna elements are connected to the feed line at the same angle, the angle can be precisely determined. However, depending on the angle, it may be necessary for the feed line to be bent in a complex or extensive manner, thus requiring a more intricate shape for the feed line.

[0091] However, if the radiating antenna elements are connected at an angle of 90°, the shape of the feed line can be simplified.

[0092] In the micro stripline array antenna, the bending shape of the feed line includes a uniform curve.

[0093] The feed line can be bent to create a corner with a predetermined angle, similar to a sawtooth. The micro-stripline array antenna can then be constructed using a feed line with such a bent corner.

[0094] However, if the feeder line has such a bent corner, some of the electrical energy propagating through the feeder line will be radiated from the bent area, resulting in a loss of electrical energy.

[0095] To solve this problem, the feed line is designed so that its curved section follows a smooth curve. Consequently, unnecessary electrical energy is avoided being radiated from the curved section of the feed line, resulting in a more efficient micro-stripline array antenna.

[0096] In the micro stripline array antenna, the feed line has a continuously serpentine, essentially S-shaped form.

[0097] Because the feed line has an S-shape, its shape can be simplified, and the arrangement in which the radiating antenna elements are connected to the feed line at a 90° angle can be easily implemented. Additionally, the S-shape ensures that the feed line bends completely and uniformly, thus improving the radiation efficiency.

[0098] In the micro stripline array antenna, each side of the feed line is connected to a plurality of the radiating antenna elements.

[0099] According to the previously described micro-stripline array antenna design, a so-called series-fed micro-stripline array antenna is implemented, in which the radiating antenna elements are connected to the sides of the feed line. This allows for a more efficient micro-stripline array antenna, reducing the loss of supplied electrical energy and achieving a desired radiation pattern.

[0100] According to the micro stripline array antenna, the radiating antenna elements connected to one side of the feed stripline are connected to areas corresponding to the mean areas between each of the two adjacent radiating antenna elements connected to the other side of the feed stripline.

[0101] According to the micro-stripline array antenna, which is designed as described above, the radiating antenna elements, which are connected to two sides of the feed line, are arranged alternately along the feed line. This allows radio waves to be efficiently radiated and received.

Claims

[1] Micro stripline array antenna (1, 10, 40, 50) with a dielectric substrate (12) on the back of which a conductive grounding plate (11) is formed, and a stripline (13) formed on the dielectric substrate (12), wherein the strip conductor (13) comprises a feed strip line (3, 15, 43, 51) which is linear and extends in a predetermined direction of extension, and at least two radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a - 5d; 21a - 21v; 41a - 41c) of a predetermined length, wherein at least one of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a - 5d; 21a - 21v; 41a - 41c) is connected to one side of the feed strip line (3, 15, 43, 51) and at least one of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a - 5d; 21a - 21v; 41a - 41c) is connected to the other side of the feed line (3, 15, 43, 51), the longitudinal directions of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a- 5d; 21a - 21v; 41a - 41c) are parallel to each other and are arranged at an angle other than 90° with respect to the direction of extension, the feed line (3, 15, 43, 51) has a partially or completely curved shape and extends completely in the direction of extension, so that the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a - 5d; 21a - 21v; 41a - 41c) are connected to the feed line (3, 15, 43, 51) at the same angle, and each of the sides of the feed line (3, 15, 43, 51) is connected to a plurality of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a- 5d; 21a - 21v; 41a - 41c), characterized by , that the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a- 5d; 21a - 21v; 41a - 41c) which are connected to one side of the feed line (3, 15, 43, 51), are connected to areas of the feed line which correspond to the middle areas between adjacent two of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a- 5d; 21a - 21v; 41a - 41c) which are connected to the other side of the feed line (3, 15, 43, 51). [2] Micro stripline array antenna (1, 10, 40, 50) with a dielectric substrate (12) on the back of which a conductive grounding plate (11) is formed, and a stripline (13) formed on the dielectric substrate (12), wherein the strip conductor (13) comprises a feed strip line (3, 15, 43, 51) which is linear and extends in a predetermined direction of extension, and at least two radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a - 5d; 21a - 21v; 41a - 41c) of a predetermined length, wherein at least one of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a - 5d; 21a - 21v; 41a - 41c) is connected to one side of the feed strip line (3, 15, 43, 51) and at least one of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a - 5d; 21a - 21v; 41a - 41c) is connected to the other side of the feed line (3, 15, 43, 51), the longitudinal directions of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a - 5d; 21a - 21v; 41a - 41c) are parallel to each other and are arranged at an angle other than 90° with respect to the direction of extension, and the feed line (3, 15, 43, 51) has a partially or completely curved shape and extends completely in the direction of extension, so that the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a- 5d; 21a - 21v; 41a - 41c) are connected to the feed line (3, 15, 43, 51) at the same angle, characterized by , that the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a- 5d; 21a - 21v; 41a - 41c), which are connected to the two sides of the feed line (3, 15, 43, 51), are arranged alternately along the feed line (3, 15, 43, 51). [3] Micro stripline array antenna (1, 10, 40, 50) according to claim 1 or 2, characterized by , that the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a- 5d; 21a -21v; 41a - 41c) are connected to the feed line (3, 15, 43, 51) at an angle of 90°. [4] Micro stripline array antenna (1, 10, 40, 50) according to claim 1 or 2, characterized by , that the bending shape of the feeder line (3, 15, 43, 51) includes a uniform curve. [5] Micro stripline array antenna (1, 10, 40, 50) according to claim 4, characterized by , that the feeder line (3, 15, 43, 51) has a continuously serpentine, essentially S-shaped form. [6] Micro stripline array antenna (1, 10, 40, 50) according to claim 2, characterized by , that each of the sides of the feeder line (3, 15, 43, 51) is connected to a plurality of the radiating antenna elements (6a - 6d; 22a - 22v; 42a - 42c, 5a- 5d; 21a - 21v; 41a - 41c).

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