A Vivaldi antenna and design method

Abstract

The present disclosure provides a Vivaldi antenna and a design method, comprising a dielectric substrate, comprising a circular arc dielectric substrate and a rectangular dielectric substrate, wherein the circular arc dielectric substrate is closely connected to the rectangular dielectric substrate; a radiation patch, wherein the radiation patch is respectively located on a top layer and a bottom layer of the dielectric substrate; a grounding structure, wherein the grounding structure is located on the top layer of the dielectric substrate; a feeder, wherein the feeder is located on the bottom layer of the dielectric substrate; a fan-shaped expansion structure is loaded at the opening of the radiation patch, wherein the fan-shaped expansion structure is symmetrical about the vertical central axis of the antenna; a plurality of fan-shaped directors are loaded on the two-layer surface of the dielectric substrate, wherein the fan-shaped radii of the plurality of fan-shaped directors are the same, the fan-shaped curvatures are the same, and the spacings between adjacent fan-shaped directors are the same; the aperture of the antenna is effectively expanded, the gain of the antenna is enhanced, and the antenna loss is not affected at the same time.

Description

Technical Field

[0001] The present disclosure relates to the technical field of designing small antennas for close-range detection, and in particular to a Vivaldi antenna and a design method thereof. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] Ultra-wideband wireless communication technology has been studied for applications such as detection, imaging and positioning due to its high pulse integration, fast communication speed and low cost. General ultra-wideband equipment usually includes ultra-wideband signal generation and storage equipment, RF front-end and RF terminal parts. The required equipment is simple and cheap. The RF front-end of ultra-wideband terminal equipment usually requires ultra-wideband antenna matching, so the performance of ultra-wideband antenna indirectly affects the function and efficiency of ultra-wideband terminal equipment. Generally speaking, ultra-wideband antennas are divided into two categories: omnidirectional antennas and directional antennas. Among them, directional antennas have a fixed direction and can emit energy in the required detection direction to achieve ideal experimental results. Among many directional antennas, Vivaldi antennas are widely used due to their low profile, low cross-polarization, compact structure and other characteristics. Vivaldi antennas were first proposed by Gibson in 1978. Later in 1988, based on the antenna proposed by Gibson, Gait designed a deformed Vivaldi antenna, which is also the earliest Vivaldi antenna. Compared with the original Vivaldi antenna, the radiation patches of the extended Vivaldi antenna are on both sides of the antenna substrate, which can solve the antenna feeding problem and improve the feeding efficiency to a certain extent.

[0004] However, the original Vivaldi antenna still has a lot of room for improvement in performance, especially in gain and directivity. Although existing methods have improved gain and directivity, they have destroyed the loss characteristics of the antenna. Summary of the invention

[0005] In order to solve the above problems, the present disclosure proposes a Vivaldi antenna and a design method, which can expand the aperture of the antenna, enhance the gain of the antenna, and further guide the radiation beam of the antenna, while ensuring the loss characteristics of the Vivaldi antenna, enhancing the directivity of the antenna and improving the gain.

[0006] According to some embodiments, the present disclosure adopts the following technical solutions:

[0007] A Vivaldi antenna, comprising:

[0008] The dielectric substrate comprises a circular-arc dielectric substrate and a rectangular dielectric substrate, wherein the circular-arc dielectric substrate is closely connected to the rectangular dielectric substrate;

[0009] Radiating patches, the radiating patches are respectively located on the top layer and the bottom layer of the dielectric substrate;

[0010] A grounding structure, wherein the grounding structure is located on a top layer of the dielectric substrate;

[0011] A feeder line is located at the bottom layer of the dielectric substrate.

[0012] Furthermore, the arc-shaped dielectric substrate and the rectangular dielectric substrate are made of the same material and have the same thickness, and the length of the rectangular dielectric substrate is twice the radius of the arc-shaped dielectric substrate.

[0013] Furthermore, the edge of a single patch of the radiation patch is surrounded by an outer index line, an inner index line and an arc line.

[0014] Furthermore, the slope of the outer index line is twice the slope of the inner index line, the outer index line and the inner index line have the same horizontal coordinate, and the end points are both located on the arc line constituting the edge of the radiation patch.

[0015] Furthermore, the arc line has the same center as the arc of the arc-shaped dielectric substrate, and the radius of the arc line is smaller than the arc radius of the arc line dielectric substrate.

[0016] Furthermore, the grounding structure is formed by closely connecting and combining an exponential grounding structure and a rectangular grounding structure, and the length of the rectangular part of the rectangular grounding structure is the same as the length of the rectangular dielectric substrate.

[0017] Furthermore, the planar shape of the feed line is a rectangle, the width of which is equal to the distance between the starting points of two exponential lines at the edge of the radiation patch, and a fan-shaped expansion structure is loaded at the opening of the radiation patch, and the fan-shaped expansion structure is symmetrical about the vertical center axis of the antenna.

[0018] Furthermore, a plurality of fan-shaped directors are loaded on the two surfaces of the dielectric substrate, the fan-shaped radii of the plurality of fan-shaped directors are the same, the fan-shaped curvatures are the same, and the intervals between adjacent fan-shaped directors are the same.

[0019] According to some embodiments, the present disclosure adopts the following technical solutions:

[0020] A design method for a Vivaldi antenna, comprising:

[0021] Drawing a dielectric substrate, including drawing an arc-shaped dielectric substrate and drawing a rectangular dielectric substrate;

[0022] Drawing the radiation patch, including drawing the exponential line edge and arc edge of the patch;

[0023] Draw the ground structure for balanced feed of top radiating patch;

[0024] The feed lines are designed to transfer energy to the radiating patches.

[0025] Furthermore, the fan-shaped expansion structure loaded at the opening of the radiation patch is drawn, including the design of the radius and curvature of the fan-shaped expansion structure;

[0026] The fan-shaped directors loaded on the two surfaces of the dielectric substrate are drawn, including the radius and curvature of a single fan-shaped director and the design of the distribution of multiple directors, which are used to guide the radiation beam of the antenna at the opening.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The dielectric substrate of the Vivaldi antenna structure proposed in the present disclosure adopts a structure combining a circular arc dielectric substrate and a rectangular dielectric substrate. Compared with a conventional single rectangular structure, under the condition of the same external dimensions, the dielectric substrate of the Vivaldi antenna structure proposed in the present disclosure not only saves materials, but also has the advantages of miniaturization and simple structure.

[0029] The antenna disclosed in the present invention adds a fan-shaped expansion structure with the same material and thickness as the dielectric substrate at the opening of the radiation patch, so as to effectively expand the aperture of the antenna and enhance the gain of the antenna without affecting the antenna loss.

[0030] The antenna disclosed herein has multiple fan-shaped directors of the same size and equal intervals added to both sides of the dielectric substrate along the central axis of the radio frequency to guide the radiation beam of the radio frequency signal and improve the stability of the directional radiation of the antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure.

[0032] Figure 1 is a front view of the original Vivaldi antenna provided by the present disclosure;

[0033] Figure 2 is a back view of the original Vivaldi antenna provided by the present disclosure;

[0034] Figure 3 is a front view of a Vivaldi antenna loaded with a fan-shaped expansion structure in an embodiment provided by the present disclosure;

[0035] Figure 4 It is a front view of a Vivaldi antenna loaded with a fan-shaped expansion structure and a plurality of fan-shaped directors in an embodiment provided by the present disclosure;

[0036] Figure 5 is the S11 diagram of the original Vivaldi antenna provided by the present disclosure;

[0037] Figure 6 It is a diagram S11 of a Vivaldi antenna loaded with a fan-shaped expansion structure in an embodiment provided by the present disclosure;

[0038] Figure 7 It is the S11 diagram of the Vivaldi antenna designed by the present disclosure and loaded with a fan-shaped expansion structure and multiple fan-shaped directors;

[0039] Figure 8 is a standing wave ratio diagram of the original Vivaldi antenna provided by the present disclosure;

[0040] Fig. 9 It is a standing wave ratio diagram of the extended Vivaldi antenna loaded with a fan-shaped expansion structure in the embodiment provided by the present disclosure;

[0041] Fig.10 It is a standing wave ratio diagram of a parallel Vivaldi antenna loaded with a fan-shaped expansion structure and a plurality of fan-shaped directors in an embodiment provided by the present disclosure;

[0042] Fig.11 is the gain diagram of the original Vivaldi antenna provided by the present disclosure;

[0043] Fig.12 It is a gain diagram of a Vivaldi antenna loaded with a fan-shaped expansion structure in an embodiment provided by the present disclosure;

[0044] Fig.13 It is a gain diagram of a Vivaldi antenna loaded with a fan-shaped expansion structure and a plurality of fan-shaped directors in an embodiment provided by the present disclosure;

[0045] Fig.14 is the vertical radiation pattern of the original Vivaldi antenna provided by the present disclosure at 3 GHz;

[0046] Fig.15 It is the vertical radiation pattern of the Vivaldi antenna loaded with the fan-shaped expansion structure at 3GHz in the embodiment provided by the present disclosure;

[0047] Fig.16 It is a vertical radiation pattern of a Vivaldi antenna loaded with a fan-shaped expansion structure and a plurality of fan-shaped directors at 3 GHz in an embodiment provided by the present disclosure;

[0048] Fig.17 is the vertical radiation pattern of the original Vivaldi antenna provided by the present disclosure at 5 GHz;

[0049] Fig.18 It is a vertical radiation pattern of the Vivaldi antenna loaded with a fan-shaped expansion structure at 5GHz in the embodiment provided by the present disclosure;

[0050] Fig.19 It is a vertical radiation pattern of a Vivaldi antenna loaded with a fan-shaped expansion structure and a plurality of fan-shaped directors at 5 GHz in an embodiment provided by the present disclosure;

[0051] Fig. 20 is the vertical radiation pattern of the original Vivaldi antenna provided by the present disclosure at 7 GHz;

[0052] Fig.21 It is a vertical radiation pattern of the Vivaldi antenna loaded with a fan-shaped expansion structure at 7 GHz in the embodiment provided by the present disclosure;

[0053] Fig. 22 It is a vertical radiation pattern of a Vivaldi antenna loaded with a fan-shaped expansion structure and multiple fan-shaped directors at 7 GHz in an embodiment provided by the present disclosure;

[0054] Fig.23 is the vertical radiation pattern of the original Vivaldi antenna provided by the present disclosure at 9 GHz;

[0055] Fig.24 It is the vertical radiation pattern of the Vivaldi antenna loaded with a fan-shaped expansion structure at 9GHz in the embodiment provided by the present disclosure;

[0056] Fig.25 It is a vertical radiation pattern of a Vivaldi antenna loaded with a fan-shaped expansion structure and a plurality of fan-shaped directors at 9 GHz in an embodiment provided by the present disclosure;

[0057] Fig.26 is the horizontal radiation pattern of the original Vivaldi antenna provided by the present disclosure at 3 GHz;

[0058] Fig. 27 It is the horizontal radiation pattern of the Vivaldi antenna loaded with a fan-shaped expansion structure at 3GHz in the embodiment provided by the present disclosure;

[0059] Fig.28 It is the horizontal radiation pattern of the Vivaldi antenna loaded with a fan-shaped expansion structure and multiple fan-shaped directors at 3GHz in the embodiment provided by the present disclosure;

[0060] Fig.29 is the horizontal radiation pattern of the original Vivaldi antenna provided by the present disclosure at 5 GHz;

[0061] Fig.30 It is the horizontal radiation pattern of the Vivaldi antenna loaded with a fan-shaped expansion structure at 5 GHz in the embodiment provided by the present disclosure;

[0062] Fig.31 It is the horizontal radiation pattern of the Vivaldi antenna loaded with a fan-shaped expansion structure and multiple fan-shaped directors at 5GHz in the embodiment provided by the present disclosure;

[0063] Fig.32 is the horizontal radiation pattern of the original Vivaldi antenna provided by the present disclosure at 7 GHz;

[0064] Fig.33 It is the horizontal radiation pattern of the Vivaldi antenna loaded with a fan-shaped expansion structure at 7 GHz in the embodiment provided by the present disclosure;

[0065] Fig.34 It is the horizontal radiation pattern of the Vivaldi antenna loaded with a fan-shaped expansion structure and multiple fan-shaped directors at 7GHz in the embodiment provided by the present disclosure;

[0066] Fig.35 is the horizontal radiation pattern of the original Vivaldi antenna provided by the present disclosure at 9 GHz;

[0067] Fig.36 It is the horizontal radiation pattern of the Vivaldi antenna loaded with a fan-shaped expansion structure at 9GHz in the embodiment provided by the present disclosure;

[0068] Fig.37 This is the horizontal radiation pattern of the 9GHz Vivaldi antenna loaded with a fan-shaped expansion structure and multiple fan-shaped directors in the embodiment provided by the present disclosure. DETAILED DESCRIPTION

[0069] The present disclosure is further described below in conjunction with the accompanying drawings and embodiments.

[0070] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanation of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present disclosure belongs.

[0071] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0072] Example 1

[0073] In one embodiment of the present disclosure, a Vivaldi antenna is provided, such as Figure 1 As shown, it includes a dielectric substrate, including a circular arc dielectric substrate 1 and a rectangular dielectric substrate 2, wherein the circular arc dielectric substrate 1 is closely connected to the rectangular dielectric substrate 2; the circular arc dielectric substrate and the rectangular dielectric substrate are made of the same material and have the same thickness, and the length of the rectangular dielectric substrate is twice the radius of the circular arc dielectric substrate.

[0074] The radiation patch is respectively located on the top layer and the bottom layer of the dielectric substrate; the radiation patch is divided into two parts, respectively located on the top layer and the bottom layer of the dielectric substrate.

[0075] A grounding structure, wherein the grounding structure is located on a top layer of the dielectric substrate;

[0076] A feeder line is located at the bottom layer of the dielectric substrate.

[0077] Specifically, the main contour edge of the radiation patch includes two index lines and an arc line, the top radiation patch is connected to the ground structure, and the bottom radiation patch is connected to the feed line; the edge of a single patch of the radiation patch is surrounded by an outer index line, an inner index line and an arc line. The slope of the outer index line is twice the slope of the inner index line, the outer index line and the inner index line have the same horizontal coordinates, and the end points are both located on the arc line that constitutes the edge of the radiation patch. The arc line has the same center as the arc of the arc-shaped dielectric substrate, and the radius of the arc line is smaller than the arc radius of the arc line dielectric substrate.

[0078] The grounding structure is composed of an exponential grounding structure and a rectangular grounding structure that are closely connected and combined, and the length of the rectangular part of the rectangular grounding structure is the same as the length of the rectangular dielectric substrate. The main outline of the exponential structure is two exponential lines, and the distance between the end points of the two exponential lines of the grounding structure is equal to the distance between the starting points of the two exponential lines of the radiation patch.

[0079] The planar shape of the feed line is a rectangle, and its width is equal to the distance between the starting points of the two exponential lines at the edge of the radiation patch. A fan-shaped expansion structure is loaded at the opening of the radiation patch to increase the aperture of the antenna and enhance the gain of the antenna. The fan-shaped expansion structure is symmetrical about the vertical center axis of the antenna. Multiple fan-shaped directors are loaded on the two surfaces of the dielectric substrate to guide the radiation beam of the antenna and improve the directional radiation performance of the antenna. The multiple fan-shaped directors have the same curvature and radius, that is, the multiple fan-shaped directors have the same fan radius, the same fan curvature, and the same spacing between adjacent fan-shaped directors.

[0080] As an embodiment, the top radiation patch and the bottom radiation patch are symmetrical about the plane z=-0.5*h, where h is the thickness of the substrate. The gradient rates of the two exponential lines of the single-layer radiation patch on the dielectric substrate are different.

[0081] As an embodiment, the length of the rectangular substrate is the same as the diameter of the arc-shaped substrate.

[0082] The width of the rectangular substrate is slightly greater than the width of the rectangular grounding structure.

[0083] As an embodiment, the plane shape of the feed line is a rectangle. The width of the feed line is the same as the distance between the starting points of the two index lines constituting the patch.

[0084] As an embodiment, the width of the feed line is the same as the distance between the starting points of the two index lines constituting the patch.

[0085] As an embodiment, the radius of the arc-shaped edge of the radiation patch is slightly smaller than the radius of the arc-shaped substrate.

[0086] As an embodiment, the fan-shaped expansion structure is consistent with the thickness of the substrate and is closely connected. The longitudinal opening width of the fan-shaped expansion structure is the same as the diameter of the arc-shaped substrate. The fan-shaped expansion structure is made of the same material as the substrate, both of which are made of FR-4 material. The fan-shaped expansion structure is symmetrical about the straight line y=r, where r is the radius of the arc-shaped substrate. The fan-shaped circle of the fan-shaped expansion structure is not concentric with the arc-shaped edge of the patch and the center of the arc-shaped substrate.

[0087] As an embodiment, the number of fan-shaped directors loaded on the single substrate layer is multiple. The number of fan-shaped directors loaded on the two substrate layers is the same. The single fan-shaped directors loaded on the two substrate layers are symmetrical about the straight line y=r, where r is the radius of the arc-shaped substrate. The fan-shaped directors are of the same size.

[0088] The dimensions of the fan-shaped director include the fan-shaped radius and fan-shaped curvature of a single fan-shaped director and the spacing between adjacent fan-shaped directors.

[0089] The director on the top layer of the substrate is symmetrical with the director on the bottom layer of the substrate about a plane z=-0.5*h, where h is the thickness of the substrate.

[0090] The material of the single sector director is consistent with that of the patch, the grounding structure and the feed line, and all of them are ideal conductors.

[0091] Example 2

[0092] An embodiment of the present disclosure provides a design method for a Vivaldi antenna, including:

[0093] Drawing a dielectric substrate, including drawing an arc-shaped dielectric substrate and drawing a rectangular dielectric substrate;

[0094] Drawing the radiation patch, including drawing the exponential line edge and arc edge of the patch;

[0095] Draw the ground structure for balanced feed of top radiating patch;

[0096] The feed lines are designed to transfer energy to the radiating patches.

[0097] Furthermore, the fan-shaped expansion structure loaded at the opening of the radiation patch is drawn, including the design of the radius and curvature of the fan-shaped expansion structure;

[0098] The fan-shaped directors loaded on the two surfaces of the dielectric substrate are drawn, including the radius and curvature of a single fan-shaped director and the design of the distribution of multiple directors, which are used to guide the radiation beam of the antenna at the opening.

[0099] As an embodiment, the specific process of drawing the Vivaldi antenna is as follows:

[0100] like Figure 1 As shown, the dielectric substrate of the Vivaldi antenna is drawn. First, the arc-shaped dielectric substrate 1 is drawn. As shown in formula (1), the radius R of the arc-shaped dielectric substrate 1 is subject to the selection of frequency. In this embodiment, the frequency f Lis the lowest operating frequency. In this embodiment, the radius R of the arc-shaped dielectric substrate 1 is 50 mm. This size enables the antenna to operate at frequencies of 3 GHz and above. In order to meet the characteristics of miniaturization, the thickness of the arc-shaped dielectric substrate 1 is 0.8 mm. On the basis of the arc-shaped dielectric substrate 1, a rectangular dielectric substrate 2 is drawn. The length of the rectangular dielectric substrate 2 is twice the radius of the arc-shaped dielectric substrate 1. In this embodiment, the width of the rectangular dielectric substrate 2 is selected to be 20 mm, and it is closely connected to the arc-shaped dielectric substrate 1. The thickness of the rectangular dielectric substrate 2 is 0.8 mm, which ensures that the feeding loss of the entire substrate will not be too large.

[0101] R = 0.5*sqrt(2 / ε r +1)) / f L (1)

[0102] Draw the patch on the top layer of the dielectric substrate 1. First, draw the inner index line 3 of the patch. The inner index line 3 is determined by formula (2), where b i is the gradient of the inner index line 3, which determines the inclination of the index line. In this embodiment, b is 0.05. i and c i are two constants, respectively determined by formula (3) and formula (4), where (x1, y1) and (x2, y2) are the starting point coordinates and the ending point coordinates of the index line, respectively. In this embodiment, the key to the design is the selection of (x2, y2). The starting point coordinates of the inner index line 3 are set to (-20, -1). The horizontal coordinate x2 and the vertical coordinate y2 of the end point of the inner index line 3 are respectively determined by formula (5) and formula (6), r is the radius of the patch arc line 5, deg1 is the angle between the line connecting the center of the patch arc line 5 and (x2, y2) and the central axis of the antenna. In this embodiment, the radius of the patch arc line 5 is 50 mm, the center is set to the origin of the coordinate system (0, 0), and the angle deg1 is set to 20 degrees.

[0103] y i =a i *exp(b i *x)+c i (2)

[0104] a i =(y2-y1) / (exp(b*x2)-exp(b*x1)) (3)

[0105] c i =(y 1* exp(b i *x2)-y 2* exp(b1*x1)) / (exp(b i *x2)-exp(b i*x1)) (4)

[0106] x2=x c +r*cos(deg1*pi / 180) (5)

[0107] y2=y c +r*sin(deg1*pi / 180) (6)

[0108] Further, x2 is determined to be 45.11, and y2 is determined to be 16.42. According to formula (3) and formula (4), a i Determined to be 1.89, c i The inner exponential line 3 equation is y = 1.89*e (0.05*x) -16.9.

[0109] Draw the outer index line 4 of the patch. The outer index line 4 is determined by formula (7), b o is the gradient rate of the outer index line 4. In this embodiment, b o The value of is 0.1. o and c o are two constants determined by formulas (8) and (9). (x3, y3) and (x4, y4) are the starting point and end point of the outer index line 4. To ensure the symmetry of the overall structure of the antenna, the value of x3 is the same as x1, which is -20, and the value of y3 is 0.1. The horizontal coordinate x4 and the vertical coordinate y4 of the end point of the outer index line 4 are determined by formulas (10) and (11), where deg2 is the angle between the line connecting the center of the patch arc line 5 and (x2, y2) and the central axis of the antenna, and the degree is greater than deg1. In this embodiment, deg2 is set to 70 degrees.

[0110] y o =a o *exp(b o *x)+c o (7)

[0111] a o =(y4-y3) / (exp(b o *x4)-exp(b*x3)) (8)

[0112] c o =(y 3* exp(b o *x4)-y4*exp(b o *x3)) / (exp(b o* x4)-exp(b o *x3)) (9)

[0113] x4=x c+r*cos(deg2*pi / 180) (10)

[0114] y4=y c +r*sin(deg2*pi / 180) (11)

[0115] Further, x4 is determined to be 16.4, and y4 is determined to be 45.1. According to formula (8) and formula (9), a o Determined to be 8.77, c o The inner exponential line 3 equation is y = 8.77*e (0.1*x) -0.68.

[0116] Furthermore, according to r, deg1 and deg2, an arc line 5 of the edge of the patch is drawn.

[0117] Furthermore, y=0 (the central axis of the antenna) and z=-0.5*h are used to perform symmetric transformations in succession, and the patch on the bottom layer of the dielectric substrate 1 is drawn.

[0118] Draw the grounding structure. The first line draws the exponential part 6 of the grounding structure. The exponential line 6 of the grounding structure is determined by formula (12). i is the inclination of the exponential line 6. In this embodiment, the value of i is -0.4. g and j are two constants, which are determined by formula (13) and formula (14) respectively. (x5, y5) and (x6, y6) are the starting point and end point of the exponential grounding structure 6. In this embodiment, the value of y6 is the same as y3, and the value of x6 is -30. The value of x5 is -45, and the distance from y5 to the center axis of the antenna is the radius R of the arc-shaped substrate 1, which is -50 in the coordinate system.

[0119] y g =g*exp(i*x)+j(12)

[0120] g=(y6-y5) / (exp(i*x6)-exp(i*x5)) (13)

[0121] j=(y 5* exp(i*x6)-y6*exp(i*x5)) / (exp(i * x6)-exp(i*x5)) (14)

[0122] Further, according to formulas (13) and (14), g is determined to be 7.48*10 -7 , f is determined to be -0.18. According to formula (12), the equation of the exponential line 6 of the grounding structure is y = 7.48*10 -7 *e (-0.4*x) -0.18.

[0123] Furthermore, the straight line y=0 is used for symmetric transformation, and the exponential line of the lower half of the grounding structure is drawn.

[0124] Furthermore, a grounded rectangular structure 7 is drawn. The length of the rectangular grounding structure 7 is the same as the length of the rectangular dielectric substrate 2, which is twice the radius R of the arc-shaped dielectric substrate. In this embodiment, in order to ensure the overall connectivity of the grounding structure, the width of the rectangular portion 7 of the grounding structure is set to 5 mm. One end of the grounded rectangular portion 7 is closely connected to the grounding index line 6.

[0125] Further, refer to Figure 2 , draw the feed line 8 at the bottom of the substrate. In this embodiment, the plane shape of the feed line 8 is a rectangle. The width of the feed line 8 is equal to the difference between the vertical coordinate y3 of the starting point of the patch outer index line 4 and the vertical coordinate y1 of the starting point of the patch inner index line 3. The length of the feed line 8 is equal to the distance from the horizontal coordinate x1 of the starting point of the patch inner index line 3 (or the horizontal coordinate x3 of the starting point of the outer index line 4) to the edge of the rectangular dielectric substrate 2.

[0126] As an implementation method, based on the original parallel-top Vivaldi antenna, a parallel-top Vivaldi antenna loaded with a fan-shaped expansion structure is designed.

[0127] Reference Figure 3, the fan-shaped expansion structure 9 of the Vivaldi antenna is designed. In this embodiment, the function of the fan-shaped expansion structure 9 is to expand the radiation aperture of the antenna at the opening of the patch, enhance the radiation energy of the antenna at the opening, and improve the gain of the antenna in the entire frequency band. The fan radius of the fan-shaped expansion structure 9 is determined by formula (15), and (x7, y7) is the fan center of the fan-shaped expansion structure 9. In order to ensure the symmetry of the fan-shaped expansion structure 1 about the central axis of the antenna and to ensure that the improvement effect on the left and right spherical beams of the antenna in the horizontal direction is the same, in the rectangular coordinate system, the vertical coordinate y7 of the center of the fan-shaped expansion structure 9 is selected as 0. In this embodiment, the horizontal coordinate x7 of the fan center of the fan-shaped expansion structure 9 is selected as 40. (x8, y8) is the fan starting point of the fan-shaped expansion structure. Among them, the vertical coordinate y8 of the fan starting point determines the width of the fan-shaped expansion structure 9. For the fan-shaped expansion structure 9, if the width is too narrow, the expanded aperture of the antenna will increase the gain, but it will have a bad effect on the directivity of the beam, especially the beam at high frequencies; if the width is too large, the antenna after widening the aperture will cause the half-power beam width to become larger, destroying the directivity of the antenna. Therefore, in order to protect the radiation directivity of the antenna and to expand the antenna gain, the vertical coordinate y8 of the fan-shaped starting point of the fan-shaped expansion structure 9 is set to 50. For the horizontal coordinate x8 of the fan-shaped starting point of the fan-shaped expansion structure 9, it determines the length of the fan-shaped expansion structure 9. If the length of the fan-shaped expansion structure 9 is too long, it will cause excess loss when the antenna is fed, especially at the top of the substrate 1; if it is too short, the gain improvement effect of the antenna will not be significant. Therefore, in order to avoid unnecessary losses and to improve the antenna gain, in this embodiment, the length of the fan-shaped expansion structure 9 is set to 25 mm.

[0128] rs=sqrt((x8-x7)*(x8-x7)+(y8-y7)*(y8-y7)) (15)

[0129] deg r =2*arctan((y8-y7) / (x8-x7)) (16)

[0130] Further, according to (x7, y7) and (x8, y8), the radius length of the fan-shaped extension structure is determined using formula (15). Because it is necessary to ensure energy balance on both sides of the antenna centerline, the fan-shaped extension structure 9 is symmetrical about the antenna centerline, and the fan-shaped angle can be determined by formula (16). According to the fan-shaped angle, fan-shaped center and fan-shaped radius of the fan-shaped structure 9, the fan-shaped line of the fan-shaped extension structure 9 can be drawn.

[0131] Further, according to the starting point (x8, y8) of the fan line of the fan-shaped extension structure 9 and the end point (x2, y2) of the index line 3 in the patch, the straight line portion on the upper side of the antenna center axis of the fan-shaped extension structure 9 is drawn. The lower straight line of the fan-shaped extension structure 9 is drawn by using the axisymmetric transformation of the antenna center axis. In order to ensure that the radiation beam of the antenna is not affected, in this embodiment, the thickness and board material of the fan-shaped extension structure 9 are the same as those of the arc-shaped substrate 1 and the rectangular substrate 2.

[0132] On the basis of loading the sector expansion structure 9, multiple sector directors 10 are loaded in the index opening slot of the antenna. The sector director 10 can guide the radiation beam of the antenna at the opening of the antenna, weaken the level intensity of the side lobe of the radiation beam, and at the same time weaken the half-power angle width of the antenna, thereby improving the directional radiation of the antenna.

[0133] Reference Figure 4 , first design the first sector director 10. The sector radius of the sector director 10 is determined by formula (17), (x9, y9) is the sector center of the sector director 10. In order to ensure that the beam guiding effect of the director 10 on the upper and lower sides of the antenna center axis is consistent and the symmetry of the original radiation beam is not destroyed, in the rectangular coordinate system, the vertical coordinate y9 of the sector center of the first sector director 10 is determined to be 0. The horizontal coordinate x9 of the center of the sector director is set to 40. (x 10 ,y 10 ) is the starting point of the fan line of the fan director. If the distance between this point and the center of the fan circle (x 10 ,y 10 ) is too far, which will result in a too large sector radius and too large size of the entire director, which may cause unexpected losses at the opening. In order not to destroy other characteristics and improve the antenna beam, especially the radiation beam at high frequencies, in this embodiment, the point coordinates are set to (40,4.5).

[0134] rs=sqrt((x 10 -x9)*(x 10 -x9)+(y 10 -y9)*(y 10 -y9)) (17)

[0135] Furthermore, the radius and the arc of the single sector director 10 are determined according to the sector center and the sector starting point.

[0136] Furthermore, the sector line and the straight line surrounding the single director 10 are determined according to the sector radius and the curvature.

[0137] Further, based on a single fan-shaped director 10, other fan-shaped directors are drawn. In the present embodiment, the interval between adjacent fan-shaped directors is 2 mm, and the number of directors on a single layer of substrate is 5. The design of all directors on the top layer of the substrate is completed according to the interval between the fan-shaped directors and the number of fan-shaped directors on the single-layer substrate. The directors on the bottom layer of the substrate are drawn using symmetry. In the present embodiment, the material and thickness of all directors are consistent with the patch.

[0138] As an embodiment, the antenna is modeled using CST2020, and the process is as follows:

[0139] Design arc-shaped substrate 1. With the origin of the coordinate system as the origin, draw a circle with a radius of 50 mm in the xOy plane. With the z-axis as the extension direction, expand the arc into a 0.8 mm thick three-dimensional structure along the negative half axis of the z-axis. The three-dimensional structure is used as the arc-shaped substrate 1, and the material is FR-4.

[0140] Draw rectangular substrate 2. Starting from (-50,50,0), draw a cuboid with a length of 100mm, a width of 20mm, and a thickness of 0.8mm as rectangular substrate 2. The length, width, and height of the cuboid extend along the positive half axis of the x-axis, the negative half axis of the y-axis, and the negative half axis of the z-axis, respectively. The cuboid material is FR-4. Using the addition function in the Boolean operation of CST, combine the arc-shaped substrate 1 and the rectangular substrate 2 to form a complete substrate.

[0141] Draw the top patch of the substrate. According to the curve equation y = 1.89*e (0.05*x) -16.9, with (x1,y1,0) as the starting point and (x2,y2,0) as the end point, draw the inner index line 3 of the top patch of the substrate. According to the curve equation y = 7.48*10 -7 *e (-0.4*x) -0.18, with (x3,y3,0) as the starting point and (x4,y4,0) as the end point, draw the outer index line 4 of the top patch of the substrate. With (x4,y4,0) as the center, R as the radius, (x4,y4,0) as the starting point, (x2,y2,0) as the end point, draw the arc line 5. With (x1,y1,0) as the starting point and (x3,y3,0) as the end point, draw the straight line x=x1. Using the addition function of Boolean operation, combine the inner index line 3, the outer index line 4, the arc line 5 and the straight line x=x1. Extend the combined curve along the positive direction of the z-axis by 0.035mm to form an index patch. The material of the index patch is set to an ideal conductor.

[0142] Draw the bottom patch of the substrate. Use the mirror function of Boolean operation, take plane y=0 as the symmetry axis, copy the top radiation patch and mirror the copied patch. Take plane z=-0.5*h (h is the thickness of the substrate) as the symmetry axis, mirror the mirrored patch again, and complete the drawing of the bottom patch of the substrate.

[0143] Draw the ground structure of the top layer of the substrate. According to the curve equation y = 1.89*e (0.05*x) -16.9, with (x1,y1,0) as the starting point and (x2,y2,0) as the end point, draw the index line 6 of the grounding structure. Using the mirror function, according to the plane y=0, copy the index line 6 and mirror the copied index line to the lower side of the antenna axis. With (x1,y1,0) as the starting point, draw a rectangle 7 with a length of 100mm and a width of 5mm. Combine the two index lines and rectangle 7. Extend the combined line along the positive direction of the z-axis by 0.035mm to form a complete grounding structure. The material of the grounding structure is set to an ideal conductor.

[0144] Draw the feeding structure 8 of the bottom layer of the substrate. Starting from (x1, y1, -h), draw a cuboid with a length of 30 mm, a width of 2 mm, and a thickness of 0.035 mm as the feeding line 8. The length, width, and thickness of the cuboid extend along the negative half axis of the x-axis, the positive half axis of the y-axis, and the negative half axis of the z-axis, respectively. The material of the cuboid is selected as an ideal conductor.

[0145] Draw the fan-shaped extension structure 9. With (x7, y7, 0) as the fan circle and (x8, y8, 0) as the starting point of the fan, draw the fan-shaped arc part with a radius of 40mm and an angle of 130 degrees. Connect points (x2, y2, 0) and (x8, y8, 0) to draw the fan-shaped straight line part on the upper side of the antenna centerline. Using the mirror symmetry function, with y=0 as the axis of symmetry, draw the fan-shaped straight line part on the lower side of the antenna centerline. Connect points (x2, y2, 0) and (x2, -y2, 0) to form another straight line. Expand the above four curves by 0.8mm along the negative half axis of the z-axis to form the fan-shaped extension structure 9. The material of the fan-shaped extension structure is FR-4. Using the Boolean operation addition function, the fan-shaped extension structure 9 and the substrate 1 are combined to form a complete structure.

[0146] Draw a sector director 10. With (x9,y9,0) as the sector center, 5mm as the sector radius, and (x 10 ,y 10 ,0) as the starting point, draw a 130-degree fan-shaped arc. Connect (x9,y9,0) and (x 10 ,y 10,0), draw the fan radius on the upper side of the antenna centerline. Use the mirror function, take the plane y=0 as the symmetry axis, and draw the fan radius on the lower side of the antenna centerline. Use Boolean operation to combine the above three lines. Extend the combined curve along the positive half axis of the z-axis by 0.035mm to form a single fan-shaped director 10. The material of the single director 10 is set to an ideal conductor. Use the translation transformation function to translate the single director along the positive half axis of the x-axis. The number of translations is 4 times to ensure that there are 5 directors on a single side of the substrate; the distance of each translation is 68mm to ensure that the distance between adjacent fan-shaped directors is 5mm. Copy all the fan-shaped directors on the top layer of the substrate, and use the mirror function to mirror the copied fan-shaped directors to the bottom layer of the substrate to complete the drawing of all the fan-shaped directors on the surface of the antenna substrate.

[0147] The antenna is simulated using the CST 2020 time domain solver. Figures 5 to 37 Analyze the simulation results.

[0148] Figures 5 to 7 is the simulation result of S11 of three antennas. Figure 5 It can be seen that the original Vivaldi antenna based on the new substrate has an S11 lower than -10dB in the 3-10GHz frequency band, and the first resonant frequency appears at 3.25GHz. Figure 6 In the experiment, the first resonant frequency of the Vivaldi antenna with the fan-shaped expansion structure dropped slightly, and the S11 in the range of 3-10GHz did not show any obvious increase or fluctuation. Figure 8 In the example, after the fan-shaped director is loaded, the first resonant frequency rises slightly, but still remains near 3.25 GHz, and S11 still does not deteriorate within 3-10 GHz. In summary, the antenna based on the new substrate, loaded with a fan-shaped expansion structure and a fan-shaped director proposed in this embodiment has good return loss characteristics within 3-10 GHz, and the radiated energy can be well radiated into space and is not absorbed by the antenna itself. The fluctuation amplitude of the S11 curve of the antenna is stable, indicating that the frequency domain characteristics of the antenna are stable; in addition, the resonant frequency of the antenna is low, indicating that the antenna can obtain good impedance matching characteristics at low frequencies.

[0149] Figures 8 to 10 The simulation results of the standing wave ratio of three antennas changing with frequency. The standing wave ratio reflects the matching of the antenna energy radiation and the feeder impedance. Figure 8 It can be seen that the standing wave ratio of the Vivaldi antenna based on the new substrate is less than 1.8 in the range of 3-10GHz. Fig. 9 The VSWR of the antenna shown is still less than 1.8. The VSWR near 4.5 GHz and 7.5 GHz also decreases, gradually approaching 1.6. After loading the sector director, Fig.10 As shown in the figure, the antenna's standing wave ratio is still below 1.8, and it has dropped below 1.6 near 7.5GHz, and it drops again near 4.5GHz. In summary, after loading the fan-shaped expansion structure and the fan-shaped director, the antenna's standing wave ratio is still below 2, which meets the needs of ultra-wideband detection and other applications. In addition, the antenna's standing wave ratio is below 1.6 in most frequency bands, indicating that the antenna has good impedance matching and high energy radiation rate.

[0150] Figures 11 to 13 is the result of the gain of the three antennas changing with frequency. Fig.11 In the 3-10GHz range, the Dual-Tuo Vivaldi antenna based on the new substrate has good gain. In the 5-7GHz range, the antenna gain fluctuates around 6dBi. After 8GHz, the antenna gain exceeds 7dBi, with a peak gain of 7.7dBi at 9GHz. Fig.12 In the , the antenna loaded with the fan-shaped expansion structure has improved gain in the entire frequency band. After 5GHz, the gain increase exceeds 1dBi. After 7.8GHz, the gain of the antenna has been above 8dBi, which is higher than the peak gain of the original antenna. At 9GHz, the antenna loaded with the fan-shaped expansion structure reaches 9.2dBi, which is 1.5dBi higher than the original antenna. Fig.13 In the 3-10GHz range, the antenna gain is further improved by loading multiple sector directors on the basis of the sector expansion structure. After 5GHz, the gain of the antenna is higher than 7dBi at all frequencies, especially after 8GHz, the gain of the antenna is always higher than 9dBi. At 9GHz, the peak gain of the antenna reaches 10.2dBi, which is higher than the 10.2dBi of the 9GHz antenna. Fig.12 The peak gain in the antenna is increased by 1dBi. In summary, adding a fan-shaped expansion structure and multiple fan-shaped directors can effectively increase the gain and reduce the signal distortion of the antenna in practical applications.

[0151] Figures 14 to 25 The vertical radiation patterns of the three antennas at 3GHz, 5GHz, 7GHz, and 9GHz are shown. Figures 14 to 17 It can be seen from the figure that the Vivaldi antenna based on the new substrate meets the directional radiation characteristics at all frequency points. Figures 18 to 21 It can be seen that the main lobe level intensity of the antenna pattern loaded with the extended structure has been improved at the four selected frequency points, especially at 7GHz and 9GHz, the increase has exceeded 1dBi; the side lobe intensity has decreased, and the decrease has been around 1dBi; in addition, the half-power beam angle of the antenna has been reduced. Figures 22 to 25It can be seen that the main lobe intensity of the antenna beam is once again improved at all frequency points, and is increased by 1.3dBi again at 7GHz. This is because a fan-shaped director is loaded at the opening of the antenna, and the antenna beam is guided; the sidelobe intensity of the antenna beam decreases again, and the decrease rate exceeds 1dBi, especially at 7GHz, the decrease rate exceeds 3dBi. After loading the fan-shaped director, the half-power beam angle of the antenna is reduced again. The reduction in half-power angle means that the directivity of the antenna is enhanced. In summary, loading the fan-shaped expansion structure and the fan-shaped director can effectively enhance the main lobe level intensity of the vertical radiation beam, weaken the sidelobe energy intensity, and at the same time reduce the half-power beam angle, thereby improving the directional radiation characteristics of the antenna.

[0152] Figures 26 to 37 The horizontal radiation patterns of the three antennas at 3GHz, 5GHz, 7GHz, and 9GHz are shown. Figures 26 to 29 It can be seen that the original antenna also satisfies the directional radiation characteristics in the horizontal direction. After loading the extended structure, Figures 30 to 33 As shown in Figure 1, the main lobe of the antenna horizontal pattern increases, especially at 5 GHz, 7 GHz and 9 GHz. In addition, the side lobes of the antenna are weakened and the half-power beam angle is reduced. After loading the sector director, as shown in Figure 1, the main lobe of the antenna horizontal pattern increases, especially at 5 GHz, 7 GHz and 9 GHz. In addition, the side lobes of the antenna are weakened and the half-power beam angle is reduced. Figure 34-37 As shown in the figure, the main lobe level intensity of the antenna's horizontal radiation pattern increases again, and the side lobe intensity decreases. At 7GHz, the increase in the main lobe intensity and the weakening of the side lobe energy are more obvious. Due to the guidance of the sector director, the half-power beam angle of the antenna decreases again at each frequency. In general, the optimization results of the antenna's horizontal radiation pattern simulation are consistent with Figures 14 to 25 The optimization results of the vertical radiation pattern shown are basically consistent. After loading the fan-shaped expansion structure and multiple directors, the main lobe level intensity of the antenna's horizontal radiation pattern increases, the side lobe intensity weakens, the half-power angle of the antenna decreases, the symmetry of the radiation pattern is not destroyed, and the directional radiation characteristics of the antenna are enhanced.

[0153] The present disclosure is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present disclosure. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0154] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0155] Although the above describes the specific implementation methods of the present disclosure in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present disclosure. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present disclosure, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present disclosure.

Claims

1. A Vivaldi antenna, characterized in that: include: The dielectric substrate comprises a circular-arc dielectric substrate and a rectangular dielectric substrate, wherein the circular-arc dielectric substrate is closely connected to the rectangular dielectric substrate; Radiating patches, the radiating patches are respectively located on the top layer and the bottom layer of the dielectric substrate; A grounding structure, wherein the grounding structure is located on a top layer of the dielectric substrate; A feeder line, the feeder line being located at the bottom layer of the dielectric substrate; The feed line has a rectangular planar shape, and its width is equal to the distance between the starting points of the two exponential lines at the edge of the radiation patch. A fan-shaped expansion structure is loaded at the opening of the radiation patch, and the fan-shaped expansion structure is symmetrical about the vertical center axis of the antenna; the edge of a single patch of the radiation patch is surrounded by an outer exponential line, an inner exponential line and an arc line; the slope of the outer exponential line is twice the slope of the inner exponential line, the outer exponential line and the inner exponential line have the same horizontal coordinates, and the end points are both located on the arc line constituting the edge of the radiation patch; Design the fan-shaped expansion structure: The fan-shaped radius of the fan-shaped expansion structure is determined by the following formula: rs=sqrt((x8-x7)*(x8-x7)+(y8-y7)*(y8-y7)) Among them, (x7, y7) is the center of the fan-shaped expansion structure, and (x8, y8) is the fan-shaped starting point of the fan-shaped expansion structure; among them, the vertical coordinate y8 of the fan-shaped starting point determines the width of the fan-shaped expansion structure; the horizontal coordinate x8 of the fan-shaped starting point determines the length of the fan-shaped expansion structure; To ensure the symmetry of the fan-shaped extension structure about the central axis of the antenna and to ensure the same improvement effect on the left and right spherical beams of the antenna in the horizontal direction, in the rectangular coordinate system, the vertical coordinate y7 of the center of the fan-shaped extension structure is selected as 0, and the horizontal coordinate x7 is selected as 40; to protect the radiation directivity of the antenna and expand the antenna gain at the same time, the vertical coordinate y8 of the fan-shaped starting point of the fan-shaped extension structure is set to 50; to avoid loss and improve the antenna gain at the same time, the length of the fan-shaped extension structure is set to 25mm; To ensure energy balance on both sides of the antenna centerline, the fan-shaped expansion structure is symmetrical about the antenna centerline, and the fan-shaped angle is determined by the following formula: degree r =2*arctan((y8-y7) / (x8-x7)) According to the fan angle, fan center and fan radius of the fan structure, the fan line of the fan-shaped extension structure is drawn; according to the starting point (x8, y8) of the fan line of the fan-shaped extension structure and the end point (x2, y2) of the index line in the patch, the straight line part on the upper side of the antenna center axis of the fan-shaped extension structure is drawn, and the lower side straight line of the fan-shaped extension structure is drawn by using the axisymmetric transformation of the antenna center axis. The thickness and board material of the fan-shaped extension structure are the same as those of the circular arc substrate and the rectangular substrate; On the basis of loading the sector expansion structure, multiple sector directors are loaded in the index opening slot of the antenna. The sector director guides the radiation beam of the antenna at the opening of the antenna, weakens the level intensity of the side lobe of the radiation beam, and at the same time weakens the half-power angle width of the antenna, thereby improving the directional radiation of the antenna. The specific steps of designing the sector director include: the sector radius of the sector director is determined by the following formula: rs=sqrt((x 10 -x9)*(x 10 -x9)+(y 10 -y9)*(y 10 -y9)) Among them, (x9, y9) is the center of the sector of the sector director. In order to ensure that the beam guiding effect of the director on the upper and lower sides of the antenna center axis is consistent and the symmetry of the original radiation beam is not destroyed, in the rectangular coordinate system, the vertical coordinate y9 of the center of the sector of the first sector director is determined to be 0, and the horizontal coordinate x9 of the center of the sector director is set to 40. In order not to destroy other characteristics and improve the antenna beam at the same time, (x 10 ,y 10 ) coordinates are set to (40,4.5); According to the center of the sector and the starting point of the sector, the radius and arc of the single sector director are determined; According to the sector radius and arc, determine the sector line and the straight line that enclose a single director; Based on a single fan-shaped director, draw other fan-shaped directors. The interval between adjacent fan-shaped directors is 2 mm, and the number of directors on a single-layer substrate is 5. Complete the design of all directors on the top layer of the substrate based on the interval between fan-shaped directors and the number of fan-shaped directors on a single-layer substrate, and draw the directors on the bottom layer of the substrate using symmetry. The material and thickness of all directors are consistent with the patch. The gain of the Vivaldi antenna based on the new substrate fluctuates within 6dBi in the range of 5-7GHz; after 8GHz, the gain of the antenna exceeds 7dBi, and the peak gain is 7.7dBi at 9GHz; the gain of the antenna loaded with the fan-shaped extension structure is improved in the entire frequency band, and after 5GHz, the increase in gain exceeds 1dBi; after 7.8GHz, the gain of the antenna is always above 8dBi, which is higher than the peak gain of the original antenna; at 9GHz, the gain of the antenna loaded with the fan-shaped extension structure reaches 9.2dBi, which is 1.5dBi higher than the original antenna; on the basis of loading the fan-shaped extension structure, the gain of the antenna loaded with multiple fan-shaped directors is further improved in the range of 3-10GHz, and after 5GHz, the gain of the antenna is higher than 7dBi at all frequencies, and after 8GHz, the gain of the antenna is always higher than 9dBi; at 9GHz, the peak gain of the antenna reaches 10.2dBi, which is 1dBi higher than the peak gain of the antenna loaded with the fan-shaped extension structure.

2. The Vivaldi antenna according to claim 1, characterized in that: The arc-shaped dielectric substrate is made of the same material and has the same thickness as the rectangular dielectric substrate, and the length of the rectangular dielectric substrate is twice the radius of the arc-shaped dielectric substrate.

3. The Vivaldi antenna according to claim 1, characterized in that: The arc line has the same center as the arc of the arc-shaped dielectric substrate, and the radius of the arc line is smaller than the arc radius of the arc line dielectric substrate.

4. The Vivaldi antenna according to claim 1, characterized in that: The grounding structure is formed by closely connecting and combining an exponential grounding structure and a rectangular grounding structure, and the length of the rectangular part of the rectangular grounding structure is the same as the length of the rectangular dielectric substrate.

5. A design method for a Vivaldi antenna, characterized in that: include: Drawing a dielectric substrate, including drawing an arc-shaped dielectric substrate and drawing a rectangular dielectric substrate; Drawing the radiation patch, including drawing the exponential line edge and arc edge of the patch; Draw the ground structure for balanced feed of top radiating patch; Designing feed lines to transfer energy to the radiating patch; The feed line has a rectangular planar shape, and its width is equal to the distance between the starting points of the two exponential lines at the edge of the radiation patch. A fan-shaped expansion structure is loaded at the opening of the radiation patch, and the fan-shaped expansion structure is symmetrical about the vertical center axis of the antenna; the edge of a single patch of the radiation patch is surrounded by an outer exponential line, an inner exponential line and an arc line; the slope of the outer exponential line is twice the slope of the inner exponential line, the outer exponential line and the inner exponential line have the same horizontal coordinates, and the end points are both located on the arc line constituting the edge of the radiation patch; Design the fan-shaped expansion structure: The fan-shaped radius of the fan-shaped expansion structure is determined by the following formula: rs=sqrt((x8-x7)*(x8-x7)+(y8-y7)*(y8-y7)); Among them, (x7, y7) is the center of the fan-shaped expansion structure, and (x8, y8) is the fan-shaped starting point of the fan-shaped expansion structure; among them, the vertical coordinate y8 of the fan-shaped starting point determines the width of the fan-shaped expansion structure; the horizontal coordinate x8 of the fan-shaped starting point determines the length of the fan-shaped expansion structure; To ensure the symmetry of the fan-shaped extension structure about the central axis of the antenna and to ensure the same improvement effect on the left and right spherical beams of the antenna in the horizontal direction, in the rectangular coordinate system, the vertical coordinate y7 of the center of the fan-shaped extension structure is selected as 0, and the horizontal coordinate x7 is selected as 40; to protect the radiation directivity of the antenna and expand the antenna gain at the same time, the vertical coordinate y8 of the fan-shaped starting point of the fan-shaped extension structure is set to 50; to avoid loss and improve the antenna gain at the same time, the length of the fan-shaped extension structure is set to 25mm; To ensure energy balance on both sides of the antenna centerline, the fan-shaped expansion structure is symmetrical about the antenna centerline, and the fan-shaped angle is determined by the following formula: degree r =2*arctan((y8-y7) / (x8-x7)); According to the fan angle, fan center and fan radius of the fan structure, the fan line of the fan-shaped extension structure is drawn; according to the starting point (x8, y8) of the fan line of the fan-shaped extension structure and the end point (x2, y2) of the index line in the patch, the straight line part on the upper side of the antenna center axis of the fan-shaped extension structure is drawn, and the lower side straight line of the fan-shaped extension structure is drawn by using the axisymmetric transformation of the antenna center axis. The thickness and board material of the fan-shaped extension structure are the same as those of the circular arc substrate and the rectangular substrate; On the basis of loading the sector expansion structure, multiple sector directors are loaded in the index opening slot of the antenna. The sector director guides the radiation beam of the antenna at the opening of the antenna, weakens the level intensity of the side lobe of the radiation beam, and at the same time weakens the half-power angle width of the antenna, thereby improving the directional radiation of the antenna. The specific steps of designing the sector director include: the sector radius of the sector director is determined by the following formula: rs=sqrt((x 10 -x9)*(x 10 -x9)+(y 10 -y9)*(y 10 -y9)) Among them, (x9, y9) is the center of the sector of the sector director. In order to ensure that the beam guiding effect of the director on the upper and lower sides of the antenna center axis is consistent and the symmetry of the original radiation beam is not destroyed, in the rectangular coordinate system, the vertical coordinate y9 of the center of the sector of the first sector director is determined to be 0, and the horizontal coordinate x9 of the center of the sector director is set to 40. In order not to destroy other characteristics and improve the antenna beam at the same time, (x 10 ,y 10 ) coordinates are set to (40,4.5); According to the center of the sector and the starting point of the sector, the radius and arc of the single sector director are determined; According to the sector radius and arc, determine the sector line and the straight line that enclose a single director; Based on a single fan-shaped director, draw other fan-shaped directors. The interval between adjacent fan-shaped directors is 2 mm, and the number of directors on a single-layer substrate is 5. Complete the design of all directors on the top layer of the substrate based on the interval between fan-shaped directors and the number of fan-shaped directors on a single-layer substrate, and draw the directors on the bottom layer of the substrate using symmetry. The material and thickness of all directors are consistent with the patch. The gain of the Vivaldi antenna based on the new substrate fluctuates within 6dBi in the range of 5-7GHz; after 8GHz, the gain of the antenna exceeds 7dBi, and the peak gain is 7.7dBi at 9GHz; the gain of the antenna loaded with the fan-shaped extension structure is improved in the entire frequency band, and after 5GHz, the increase in gain exceeds 1dBi; after 7.8GHz, the gain of the antenna is always above 8dBi, which is higher than the peak gain of the original antenna; at 9GHz, the gain of the antenna loaded with the fan-shaped extension structure reaches 9.2dBi, which is 1.5dBi higher than the original antenna; on the basis of loading the fan-shaped extension structure, the gain of the antenna loaded with multiple fan-shaped directors is further improved in the range of 3-10GHz, and after 5GHz, the gain of the antenna is higher than 7dBi at all frequencies, and after 8GHz, the gain of the antenna is always higher than 9dBi; at 9GHz, the peak gain of the antenna reaches 10.2dBi, which is 1dBi higher than the peak gain of the antenna loaded with the fan-shaped extension structure.

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