A compact dual-fed vivaldi antenna

Abstract

The application discloses a compact dual-fed Vivaldi antenna and belongs to the electromagnetic field and microwave technology field. The antenna is composed of upper and lower two radiation units which are printed on the same dielectric substrate and are centrally symmetrical about a boundary surface. The upper radiation unit comprises a feeding structure and two radiation patches. The contour line of the radiation patch is composed of a main exponential gradual change line, a secondary exponential gradual change line and a cosine type outer contour line. The cosine type outer contour line is used for parameterized slotting treatment of the radiation patch. The radiation patches of the upper and lower radiation units can be overlapped and electrically connected. The microstrip lines of the feeding structures of the two radiation units share the same ground plate. Through the dual-fed central symmetrical design and the parameterized and differentiated cosine type slotting mode, the application improves the radiation factor and the design freedom of the antenna and simultaneously realizes the compact layout, can solve the technical problems of the miniaturization of the Vivaldi antenna and the low aperture utilization rate of the Vivaldi antenna array, is suitable for array antenna arraying, and simultaneously reduces the processing and use costs.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic field and microwave technology, and specifically relates to a compact doubly fed Vivaldi antenna. Background Technology

[0002] Vivaldi antennas, also known as gradient slot antennas, are planar end-fire traveling wave antennas with advantages such as ultra-wideband, high gain, good directivity, light weight, and ease of processing and integration. They are widely used in the field of ultra-wideband technology, such as through-wall radar or ground-penetrating radar, biomedical detection, non-destructive testing, and electromagnetic vulnerability testing. In particular, they can also be used as array element antennas to build array-type ultra-wideband radiation systems to obtain greater irradiance.

[0003] The radiation performance of ultra-wideband pulsed radiating antennas such as Vivaldi antennas, including their emissivity (emissivity factor), depends on the antenna's structural dimensions and the waveform and amplitude of the excitation pulse. With the excitation pulse waveform parameters remaining constant, there are two main approaches to improving the emissivity of a Vivaldi antenna: first, increasing the excitation pulse voltage amplitude. However, for solid-state pulse sources, the output pulse amplitude is limited to a few kV, making it difficult to increase the pulse amplitude. Second, increasing the antenna size and combining design and optimization to improve the antenna's radiation performance. However, in some special applications, such as space-constrained scenarios or when constructing antenna arrays, increasing the size of a single antenna significantly increases the overall size of the array and reduces the antenna aperture utilization, greatly limiting its practical engineering applications. Conversely, keeping the antenna size constant and only making design optimizations makes it difficult to significantly improve the emissivity of a single antenna. Therefore, how to effectively improve the emissivity of a single antenna without changing its size—that is, how to radiate a greater irradiance within a limited antenna size—is one of the key challenges in the design and application of Vivaldi antennas. This problem is essentially equivalent to the miniaturization problem of Vivaldi antennas in ultra-wideband pulsed radiation.

[0004] Furthermore, when optimizing the design while keeping the dimensions constant, the only parameters available for optimization of the Vivaldi antenna are the exponentially gradient curvature and the parameters related to the different shapes of the slots. In other words, the Vivaldi antenna has very few parameters available for design and optimization, and its design freedom is very low.

[0005] In summary, Vivaldi antennas face technical challenges in design optimization and practical engineering applications, such as low design freedom and low radiation factor within a limited antenna size. Therefore, it is necessary to study more compact Vivaldi antennas to improve their design optimization freedom and significantly enhance their radiation factor within a limited size, thereby solving miniaturization challenges, especially the problems of large array volume and low aperture utilization when assembling Vivaldi antenna arrays. Summary of the Invention

[0006] (a) Technical problems to be solved The present invention aims to solve the technical problems of existing Vivaldi antennas, such as difficulty in improving the radiation factor within a limited size, low design freedom, and large array size and low aperture utilization when constructing the array.

[0007] (II) Technical Solution To address the aforementioned problems, this invention proposes a compact dual-fed Vivaldi antenna. Its core idea is to integrate two centrally symmetrical Vivaldi radiating elements onto the same dielectric substrate. Through the coupling effect between the dual-fed excitation and the radiating patch, the radiated field strength is increased without increasing the overall size. Simultaneously, a parameterized cosine-shaped slotting method is introduced, and the upper and lower elements are designed differently, thereby significantly improving the antenna's design optimization freedom. The specific technical solution is as follows: The compact dual-fed Vivaldi antenna includes an upper radiating element 1 and a lower radiating element 3. Both the upper radiating element 1 and the lower radiating element 3 are in the form of Vivaldi antennas, which are printed on the same dielectric substrate 5, and the radiating patches of the two radiating elements are centrally symmetrical about the interface between them.

[0008] The upper radiating unit 1 includes a feeding structure 10, a top radiating patch 11, and a reverse radiating patch 12. The feeding structure 10 is a transition structure from a 50Ω microstrip line to a parallel double line, used to achieve effective signal feeding and impedance matching. This structure consists of a microstrip line 13 and its transition to a parallel double line 16. The microstrip line 13 includes a ground plane 14 and a conductor strip 15. The top radiating patch 11 is printed on the top surface of the dielectric substrate 5, and its outline consists of a primary exponent gradient line 17, a secondary exponent gradient line 18, and a cosine-shaped outer contour line 19. The primary exponent gradient line 17 and the secondary exponent gradient line 18 together form part of the horn-shaped radiating structure, and the cosine-shaped outer contour line 19 is etched into the top radiating patch 11 to form a cosine-shaped groove line 20. The reverse radiating patch 12 is printed on the back side of the dielectric substrate 5. Its outline is also composed of a primary index gradient line 21, a secondary index gradient line 22, and a cosine-shaped outer outline line 23, forming a cosine-shaped groove line 24. The top radiating patch 11 is connected to the microstrip conductor 15 of the feed structure 10, and the reverse radiating patch 12 is connected to the microstrip ground plane 14 of the feed structure 10.

[0009] The lower radiating unit 3 has the same structure as the upper radiating unit 1, including a feeding structure 30, a top radiating patch 31, and a reverse radiating patch 32. The feeding structure 30 of the lower radiating unit 3 is the same as the feeding structure 10 of the upper radiating unit 1, and there is an electrical connection between their microstrip ground planes, realizing the sharing of the ground plane. Crucially, the shape of the top radiating patch 31 of the lower radiating unit 3 is the same as the reverse radiating patch 12 of the upper radiating unit 1, while the shape of the reverse radiating patch 32 of the lower radiating unit 3 is the same as the top radiating patch 11 of the upper radiating unit 1, thus forming a centrally symmetrical pattern.

[0010] As a further optimization of the present invention, the number of cosine-shaped grooves 20 and 24 on the top surface radiating patch 11 and the back surface radiating patch 12 of the upper radiating unit 1 can be different, that is, the number of cosine periods contained in their corresponding cosine-shaped outer contour lines 19 and 23 can be different. The depth of the cosine-shaped grooves on each radiating patch gradually decreases along the radiation direction (i.e., the x-direction). The width of the top surface radiating patch 11 of the upper radiating unit 1 in the electric field direction (i.e., the y-direction) can be different from the width of its principal exponent gradient line 17 in that direction. The lengths of the top surface radiating patch 11 and the back surface radiating patch 12 of the upper radiating unit 1 can also be different in the radiation direction.

[0011] The total dimension of the upper and lower radiating units in the electric field direction can be greater than half the width of the dielectric substrate 5 in that direction, but it must be ensured that there is no electrical connection between the top radiating patch 31 of the lower radiating unit 3 and the top radiating patch 11 of the upper radiating unit 1, and also no electrical connection between the reverse radiating patch 12 of the upper radiating unit 1 and the reverse radiating patch 32 of the lower radiating unit 3. The top radiating patch 31 of the lower radiating unit 3 can partially overlap with the reverse radiating patch 12 of the upper radiating unit 1, and the two can be electrically connected by providing vias to enhance coupling. The width of the microstrip ground plane shared by the upper and lower radiating unit feeding structures should be less than or equal to the width of the dielectric substrate 5.

[0012] All the aforementioned structural parameters, such as the size of each radiating patch, the gradient rate of the exponential gradient line, the number and depth of the cosine slot lines, the gradient method of the ground plane, and the overlap of the upper and lower patches, can be numerically simulated and optimized using electromagnetic simulation software to obtain the best radiation performance. Based on this dual-feed design concept, it can be further expanded to add more feed points, thereby constructing three-point fed, four-point fed, or even multi-point fed Vivaldi antenna structures.

[0013] (III) Beneficial Effects Compared with the prior art, the present invention has the following beneficial effects: 1. The compact dual-fed Vivaldi antenna provided by this invention can obtain a greater irradiance within a limited antenna size. In particular, when applied to array antenna assembly, it can effectively reduce the aperture area of ​​the array antenna when the number of signal sources is fixed, thereby increasing the aperture utilization rate. Moreover, it can obtain a higher irradiance with the same aperture area without considering the cost of signal sources. From the perspective of engineering applications, it realizes the miniaturization of antennas and array antenna systems.

[0014] 2. The compact dual-fed Vivaldi antenna provided by this invention uses a cosine curve profile to construct the grooves on the surface of the radiating patch. Under the premise of overall structural symmetry, the radiating patches of each radiating element are designed asymmetrically, turning the original invariant into an optimizable quantity. This significantly increases the degree of freedom in the design optimization of the Vivaldi antenna. Through in-depth optimization, the antenna's radiation potential can be explored to obtain better radiation performance.

[0015] 3. The compact dual-fed Vivaldi antenna provided by this invention integrates two radiating elements on the same double-sided copper-clad dielectric substrate, which can eliminate the need for additional fixing brackets and save on antenna processing, fixing and usage costs.

[0016] 4. The compact dual-fed Vivaldi antenna provided by this invention introduces a parameterized cosine slotting method, which makes antenna modeling and design optimization more convenient and faster, without the need to construct slots in the form of triangles, rectangles, trapezoids or other shapes on the radiating patch. Attached Figure Description

[0017] Figure 1 A three-dimensional wireframe diagram of a compact doubly-fed Vivaldi antenna; Figure 2 A front view of a compact dual-fed Vivaldi antenna; Figure 3 This is a radiating element above a compact dual-fed Vivaldi antenna; Figure 4 This is a compact dual-fed Vivaldi antenna with an upper radiating element feeding structure; Figure 5 This is a radiating patch on the top surface of the upper radiating element of a compact dual-fed Vivaldi antenna; Figure 6 This is a radiating patch on the reverse side of the upper radiating element of a compact dual-fed Vivaldi antenna; Figure 7 This is a compact doubly fed Vivaldi antenna dielectric substrate top surface radiating structure; Figure 8 This is a compact doubly fed Vivaldi antenna dielectric substrate reverse-side radiating structure; Figure 9 This refers to a compact dual-fed Vivaldi antenna with a radiating patch on the reverse side of the upper radiating element and a radiating patch on the top surface of the lower radiating element. Figure 10 A front view of an embodiment of a compact dual-fed Vivaldi antenna; Figure 11 This is a three-dimensional diagram of an embodiment of a compact dual-fed Vivaldi antenna.

[0018] in: 1-Upper radiating unit; 3-Lower radiating unit; 5-Dielectric substrate; 10 - Upper radiating element feeding structure; 11-Radiation patch on the top surface of the upper radiation unit; 12-Radiation patch on the reverse side of the upper radiation unit; 13-Upper radiating element-fed microstrip line; 14-Upper radiating unit feed structure microstrip ground plane; 15 - Upper radiating unit feed structure microstrip line conductor; 16- Parallel double-line feeding structure for the upper radiating unit; 17 - Gradient lines of principal indices on the top surface of the radiation patch of the upper radiation unit; 18 - Gradient lines of the sub-index of the radiation patch on the top surface of the upper radiation unit; 19 - Cosine-shaped outer contour of the radiating patch on the top surface of the upper radiating unit; 20 - Cosine-shaped grooves on the top surface of the upper radiating unit; 21 - Gradient lines of the principal index of the radiation patch on the reverse side of the upper radiation unit; 22 - Gradient lines of the sub-index of the radiation patch on the reverse side of the upper radiation unit; 23 - Cosine-shaped outer contour of the radiation patch on the reverse side of the upper radiation unit; 24 - Cosine-shaped groove line of the upper radiating unit's reverse radiating patch; 30- Lower radiating element feeding structure; 31 - Radiation patch on the top surface of the lower radiation unit; 32-Radiation patch on the reverse side of the lower radiation unit. Detailed Implementation

[0019] The technical solution provided by the present invention will be described and explained in detail below with reference to the accompanying drawings.

[0020] This invention provides a compact dual-fed Vivaldi antenna. Its working process and basic principle are as follows: two Vivaldi antenna elements that are centrally symmetrical vertically are integrated on the same dielectric substrate, and their radiating patches are overlapped or electrically connected to achieve mutual coupling of pulse currents, while retaining their respective feeding structures. That is, when the antenna is working, two signal sources simultaneously excite the two mutually coupled Vivaldi antennas on the same dielectric substrate, thereby achieving higher radiation performance with limited antenna size. At the same time, a cosine modulation curve is used to construct the slots on the surface of the radiating patch, and while maintaining the overall structural symmetry, each Vivaldi antenna element is asymmetrically designed in terms of length, width, and number of slots, which significantly improves the design optimization freedom of the antenna, thereby achieving better antenna radiation performance through optimization.

[0021] The compact doubly-fed Vivaldi antenna provided by this invention has the following structural composition: like Figure 1 , 2 As shown, a compact dual-fed Vivaldi antenna includes an upper radiating element 1 and a lower radiating element 3, both of which are Vivaldi antennas printed on the same dielectric substrate 5. Their electric field direction is... y Width in the direction is w In the direction of radiation, i.e. xThe length in the direction is l . Figure 1 In AB The dashed line represents the interface between the upper radiating element 1 and the lower radiating element 3. The radiating patches of the two radiating elements are positioned relative to the interface. AB It is centrally symmetrical.

[0022] like Figure 1 , 2 As shown in Figures 1 and 3, the upper radiating unit 1 is composed of a feeding structure 10, a top surface radiating patch 11, and a reverse surface radiating patch 12.

[0023] like Figure 3 , 4 As shown, the upper radiating element feed structure 10 is a transition structure from microstrip line 13 to parallel double line 16. The microstrip line 13 is connected by a ground plane 14 (in... y Width in the direction is w The microstrip line 13 is composed of 0 and conductor 15. The characteristic impedance of the microstrip line 13 is 50Ω, and the width of conductor 15 is... w f It can be calculated from the thickness of the dielectric substrate 5, the relative permittivity of the dielectric, and the characteristic impedance formula of the microstrip line.

[0024] like Figure 1 , 2 As shown in Figures 3, 5, and 6, the two radiating patches 11 and 12 of the upper radiating unit 1 are printed on the top and back surfaces of the dielectric substrate 5, respectively. The outer contour of the top radiating patch 11 is defined by a principal index gradient line 17 (in... x The length in the direction is l 1) Sub-index gradient line 18 (in x The length in the direction is l 2) and cosine-shaped outer contour line 19, forming a cosine-shaped groove line 20 on the top surface radiating patch. The equation of the exponential gradient line is: in, K 1 and K 2 are the undetermined constants in the equation of the exponential gradient line. α Let be the rate of change of the exponential gradient. For the main exponential gradient 17, let . K 1= K z Then the undetermined constant K 2 and gradient rate α for, In the formula, w f The width of the microstrip conductor is 15. w zThe principal index gradient line of the top surface radiating patch 11 of the upper radiating unit 1 in the electric field direction is... y Width in direction (e.g.) Figure 5 As shown, the sum of the ordinate of the endpoint of the main exponential gradient line 17 and half the width of the conductor strip 15 is the sum of the ordinates of the endpoints of the main exponential gradient line 17 and half the width of the conductor strip 15. In this example, this width is the same as the width of the top surface radiating patch 11 of the upper radiating unit 1 in the electric field direction. w 1. Different, or can be set to the same). l 1 is the main exponent gradient line 17 in the direction of electric field propagation, i.e. x Length in the direction.

[0025] Similarly, the equation of the gradient line for the secondary exponential gradient line 18 can be obtained. Furthermore, the gradient rates of the primary exponential gradient line 17 and the secondary exponential gradient line 18, and their relationship in the electric field direction... y The widths in different directions can be different.

[0026] The equation for cosine-shaped profile 19 is: In the formula, w h Let be the width of the radiating patch in the direction of the electric field. For example, for the top surface radiating patch of the upper radiating unit 1, w h = w 1; h s The width from the bottom of the cosine-shaped groove line 20 to the gradient line of the main exponent (e.g.) Figure 5 (as shown) N This means that the outline has a total of N Modulation is performed using a combination of cosine curves. l z - l h - l p For cosine-shaped contour lines in x Total length in the direction, n i For the first i The number of periods of a cosine curve. For cosine profile 19, K 1. K 2 and α All parameters are consistent with those in equation 17 of the main exponential gradient line, and l z = l 1, l h =l2, l p = l 3.

[0027] Similar to the top surface radiating patch 11, the reverse surface radiating patch 12 also consists of a principal index gradient line 21 (in... x The length in the direction is l 4) Sub-index gradient line 22 (in x The length in the direction is l 5) And together with the cosine-shaped outer contour line 23, a cosine-shaped groove line 24 is formed on the reverse radiating patch. Furthermore, the top radiating patch 11 and the reverse radiating patch 12 are aligned in the direction of electric field propagation. x Length in direction l 1. l 4 can be different, in the direction of the electric field. y Width in direction w 1. w 2 can also be different. Furthermore, the number of groove lines 20 and 24 can also be different; that is, the number of cosine curves in the two cosine-type profile lines 19 and 23 can be different. For example... Figure 3 , 5 As shown in Figures 6 and 7, the principal index gradient lines 17 and 21 of the top surface radiating patch 11 and the reverse surface radiating patch 12 form a trumpet-shaped radiating structure. CD The center line of the horn-shaped radiating structure is connected to the microstrip conductor 15 in the feed structure 10, and the reverse radiating patch 12 is connected to the ground plane 14 in the feed structure 10.

[0028] like Figure 1 , 2 As shown in Figures 7 and 8, the lower radiating unit 3 has the same structural composition as the upper radiating unit 1, also including a power supply structure 30, a top surface radiating patch 31, and a reverse surface radiating patch 32. The power supply structure 30 is identical to the power supply structure 10 in the upper radiating unit, and their ground planes are electrically connected. The top surface radiating patch 31 and the reverse surface radiating patch 32 are printed on the top and back surfaces of the dielectric substrate 5, respectively. Figure 7 , 8 As shown, the shape of the top surface radiating patch 31 of the lower radiating unit 3 is the same as the shape of the reverse radiating patch 12 of the upper radiating unit 1, and the shape of the reverse radiating patch 32 of the lower radiating unit 3 is the same as the shape of the front radiating patch 11 of the upper radiating unit 1. That is, from Figure 2 From this perspective, a compact dual-fed Vivaldi antenna is a centrally symmetrical shape.

[0029] Furthermore, such as Figure 1 , 2 As shown in Figures 3, 7, 8, and 9, the depth of the cosine-shaped grooves formed by the cosine-shaped outer contour lines on each radiating patch gradually decreases along the radiation direction. Figure 3 , 7 As shown in Figure 8, each radiating element, such as the upper radiating element 1, is in the direction of the electric field. yWidth in direction w s ( w 1+ w 2) It can be larger than the width of the dielectric substrate 5 in this direction. w Half of, but w s The value of should not cause electrical connection between the top surface radiating patch 31 of the lower radiating unit 3 and the top surface radiating patch 11 of the upper radiating unit 1, nor should it cause electrical connection between the reverse radiating patch 32 of the lower radiating unit 3 and the reverse radiating patch 12 of the upper radiating unit 1. For example... Figure 9 As shown in the front view, the top surface radiating patch 31 of the lower radiating unit 3 can overlap with the reverse surface radiating patch 12 of the upper radiating unit 1 (the overlap width is...). w c (and can be electrically connected through vias.) Figure 2 , 8 As shown, the common ground plane of the feed structures 10 and 30 of the upper radiating unit 1 and the lower radiating unit 3 is in y Width in direction w g The width of the dielectric substrate 5 in this direction is less than or equal to that of the substrate 5. w .

[0030] Because the antenna structure provided by this invention has a high degree of design freedom, the various structural parameters mentioned above, such as the width of each radiating element patch in the electric field direction, its length in the electric field propagation direction, and the number and depth of slots, can all be reasonably selected or set through numerical simulation optimization. Furthermore, based on the above ideas, more feed points can be added, such as constructing Vivaldi antennas with three-point feed, four-point feed, and multi-point feed structures.

[0031] Example The preferred embodiments of the present invention are as follows: like Figure 10 As shown, a compact dual-fed Vivaldi antenna is presented, which consists of an upper radiating element 1, a lower radiating element 3, and a dielectric substrate 5. The dielectric substrate 5 is [width missing]. w =240 mm, length l The FR4 substrate has a diameter of 300 mm and a thickness of 2 mm. The relative permittivity of the dielectric material is 4.3. The characteristic impedance of the microstrip line feeding structure for each radiating element is 50 Ω. Therefore, the conductor width of the microstrip line feeding structure for each radiating element can be calculated as follows: w f =3.9 mm; the microstrip ground plane width of each radiating element is w 0 = 80 mm.

[0032] The length of the sub-index gradient line of the top surface radiating patch 11 of the upper radiating unit 1 in the radiation direction l 2 = 20 mm, and the width in the direction of the electric field is w 1- w f / 2=88.05 mm; the length of the principal exponent gradient line in the direction of electric field radiation is l =1 = 260 mm, and its width in the electric field direction is 81.95 mm, which is smaller than the width of the secondary exponential gradient line in that direction. The equation corresponding to the principal exponential gradient line of the top surface radiating patch 11 of the upper radiating unit 1 is as follows: The equation corresponding to the sub-index gradient line of the top surface radiating patch 11 of the upper radiating unit 1 is as follows. The cosine-shaped outer contour of the top surface radiating patch 11 of the upper radiating unit 1 is modulated by combining three cosine curves, as shown in the following equation. The aforementioned cosine profile lines form various cosine-shaped grooves on the top surface radiating patch 11 of the upper radiating unit.

[0033] The length of the sub-index gradient line of the reverse radiating patch 12 of the upper radiating unit 1 in the direction of electric field radiation. l 5 = 15 mm, and the width in the direction of the electric field is w 2- w f / 2=38.05 mm; the length of the principal exponent gradient line in the direction of electric field radiation is l =4 = 240 mm, and its width in the electric field direction is 31.95 mm, which is smaller than the width of the secondary exponential gradient line in that direction. The equation corresponding to the principal exponential gradient line 21 of the reverse radiating patch 12 of the upper radiating unit 1 is as follows: The equation corresponding to the sub-index gradient line 22 of the reverse radiating patch 12 of the upper radiating unit 1 is as follows. The cosine-shaped outer contour of the reverse radiating patch 12 of the upper radiating unit 1 is also modulated by combining three cosine curves, as shown in the following equation. The aforementioned cosine contour lines are also constructed on the upper radiating unit's reverse radiating patch 12 with various cosine-shaped grooves, but these are different from the grooves on the top radiating patch, such as... Figure 10 As shown.

[0034] Furthermore, the top surface radiating patch, the reverse surface radiating patch, and the feeding structure are combined to obtain... Figure 10 The upper radiating element 1 is constructed, and the lower radiating element 3 is obtained through centrosymmetry, thus completing the modeling of a compact doubly-fed Vivaldi antenna, as shown below. Figure 11 As shown.

[0035] It should be noted that, in this preferred embodiment, such as Figure 10 As shown, the reverse radiating patch of the upper radiating element and the top radiating patch of the lower radiating element have an overlapping and intersecting portion, the width of which is... w c =20 mm.

[0036] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A compact dual-fed Vivaldi antenna, characterized in that, It includes two radiating elements, one above the other, both of which are Vivaldi antennas, printed on the same dielectric substrate, and the radiating patches of the two radiating elements are centrally symmetrical about the interface between them. The upper radiating unit includes a feeding structure and two radiating patches. The feeding structure is a transition structure from a 50Ω microstrip line to a parallel double line. The two radiating patches are printed on the top and back surfaces of the dielectric substrate, respectively. The outlines of the top and back radiating patches are composed of a primary index gradient line, a secondary index gradient line, and a cosine-shaped outer outline line. The primary index gradient line forms a trumpet-shaped radiating structure. The top radiating patch is connected to the microstrip line conductor of the feeding structure, and the back radiating patch is connected to the microstrip line ground plane of the feeding structure. The lower radiating unit has the same structure as the upper radiating unit, including the same power supply structure and two radiating patches. There is an electrical connection between the microstrip ground planes of the power supply structures of the upper and lower radiating units. The top radiating patch of the lower radiating unit has the same shape as the reverse radiating patch of the upper radiating unit, and the reverse radiating patch of the lower radiating unit has the same shape as the top radiating patch of the upper radiating unit.

2. The compact doubly-fed Vivaldi antenna according to claim 1, characterized in that, Cosine-shaped outer contour lines are used to parametrically slot the top and back surface radiating patches. The number of slots on the top and back surface radiating patches is different, that is, the number of cosine cycles contained in the cosine-shaped outer contour lines is different.

3. The compact doubly-fed Vivaldi antenna according to claim 1, characterized in that, The depth of the grooves on each radiating patch of the upper and lower radiating units gradually decreases along the radiation direction.

4. The compact doubly-fed Vivaldi antenna according to claim 1, characterized in that, The gradient rates and widths in the direction of the electric field differ between the primary and secondary exponential gradient lines.

5. The compact doubly-fed Vivaldi antenna according to claim 1, characterized in that, The width of the radiation patch on the top surface of the upper radiation unit in the direction of the electric field is different from the width of its principal exponent gradient line in the direction of the electric field.

6. The compact doubly-fed Vivaldi antenna according to claim 1, characterized in that, The size of the upper and lower radiating elements in the electric field direction is greater than half the size of the entire antenna dielectric substrate in that direction, and the top surface radiating patch of the lower radiating element is not electrically connected to the top surface radiating patch of the upper radiating element, and the back surface radiating patch of the upper radiating element is not electrically connected to the back surface radiating patch of the lower radiating element.

7. The compact doubly-fed Vivaldi antenna according to claim 1, characterized in that, The top surface radiating patch of the lower radiating unit overlaps with the reverse surface radiating patch of the upper radiating unit, and they are electrically connected through a via.

8. The compact doubly-fed Vivaldi antenna according to claim 1, characterized in that, The width of the microstrip ground plane of the upper and lower radiating element feeding structure is less than or equal to the width of the entire antenna dielectric substrate.

9. The compact doubly-fed Vivaldi antenna according to claim 1, characterized in that, The top and back radiation patches of the upper radiation unit have different lengths in the radiation direction.

10. The compact doubly-fed Vivaldi antenna according to claim 1, characterized in that, The width of each radiating patch in the electric field direction and the length in the radiation direction of each radiating patch, the gradient rate of the main and sub-index gradient lines of each radiating patch, the number and depth of the cosine slots opened in each radiating patch, the gradient method of the microstrip ground plane of the feed structure, and the overlap between the reverse radiating patch of the upper radiating element and the top radiating patch of the lower radiating element are selected or set through numerical simulation optimization. Based on the structural concept of this antenna, more feed points can be added to construct Vivaldi antennas with three-point feed, four-point feed, and multi-point feed structures.

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