A comb-saw high-gain ultra-wideband Vivaldi antenna loaded with a metasurface and a configuration method thereof

Abstract

A comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna with a loaded metasurface and its configuration method are disclosed. Vivaldi antennas inherently exhibit a trade-off between size, bandwidth, and gain, lacking standardized and comprehensive processing methods. In this invention, each side of the main patch is machined from top to bottom with multiple sawtooth-shaped flow-damping grooves and multiple curved strip-shaped notches, forming a comb-shaped curved flow arm between adjacent curved strip-shaped notches. The bottom end of the main patch is sequentially machined with a strip-shaped groove and a circular feed slot. One end of the strip-shaped groove is connected to the small end of an exponentially tapered groove, and the other end is connected to the circular feed slot. The configuration method for the comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna involves calculating the antenna's curvature and minimum operating frequency based on predetermined reference characteristic data, then performing simulation testing and optimization based on the antenna's curvature and minimum operating frequency to obtain the comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna.

Description

Technical Field

[0001] Specifically, this invention relates to a comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna with a loaded metasurface and its configuration method. Background Technology

[0002] Since its formal introduction by Gibson in 1979, the Vivaldi antenna has been widely used in many cutting-edge fields such as ultra-wideband wireless communication, short-range through-wall detection radar, medical microwave imaging, and electromagnetic sensing detection, thanks to its inherent ultra-wideband radiation capability, stable radiation gain, and excellent end-fire directivity. This type of antenna uses an exponentially tapered slot as its core radiating structure, relying on the smooth, tapered slot profile to achieve electromagnetic wave impedance transition and radiation modulation. It can maintain good impedance matching characteristics and a regular beamform over an extremely wide operating frequency range, exhibiting outstanding broadband adaptability. From the perspective of electromagnetic radiation mechanisms, the antenna aperture size and effective radiating area directly determine the electromagnetic wave focusing capability and radiation gain level. The larger the antenna's physical size, the higher the aperture utilization efficiency, the better the directional wave focusing effect, and the higher the upper limit of gain performance. However, constrained by low-frequency wavelengths, traditional Vivaldi antennas generally suffer from inherent defects such as large overall structural size, limited electrical size in the low-frequency operating band, insufficient effective radiating aperture, and low overall gain, making it difficult to adapt to the installation and use requirements of miniaturized, lightweight, and integrated portable devices. To overcome size limitations, researchers both domestically and internationally have proposed various antenna miniaturization optimization methods, including modifying fern-shaped radiating arms, etching periodic corrugated grooves at the radiating edges, and reconstructing gradient groove curves. Existing research has achieved significant results in reducing overall size and miniaturizing antennas by optimizing the contour, extending the low-frequency operating bandwidth from 4.9 GHz to 3.2 GHz. However, from an electromagnetic perspective, miniaturization inevitably reduces the effective radiating aperture and weakens the surface current distribution intensity. These purely structural shaping solutions can mostly only achieve bandwidth expansion and size reduction. Under limited physical size constraints, it is difficult to achieve simultaneous gain improvement, resulting in very limited gain improvement space and a high risk of the dilemma of simultaneous size reduction and gain attenuation. In the specialized field of gain enhancement research, current mainstream optimization methods mainly include integrating three-dimensional dielectric lenses, replacing the dielectric substrate with a high dielectric constant, and adding metal guiding structures to the front end of the radiating aperture. While these methods can directly improve the antenna's directional radiation capability and increase overall gain, they mostly require additional vertical thickness and external auxiliary structures. This not only undermines the antenna's low profile and planar advantages but also significantly increases the overall size, contradicting the original intention of compact design. Metasurface lenses, with their flexible electromagnetic wave phase modulation capabilities, have become a popular gain optimization solution in recent years. They can precisely reshape the radiating wavefront and concentrate electromagnetic energy. However, in practical applications, they often require expanding the overall antenna aperture layout, which can easily cause the overall antenna size to expand and lead to secondary problems such as high-frequency beam distortion and frequency band performance degradation. Even using a multi-structure composite hybrid loading scheme to balance bandwidth, size, and gain will greatly increase the antenna topology complexity, manufacturing difficulty, and mass production costs.In summary, Vivaldi antennas have an inherent trade-off between size, bandwidth, and gain. Under the premise of strictly limiting the overall size of the antenna and ensuring a miniaturized form, it is difficult to achieve the goal of efficiently concentrating electromagnetic wave energy, significantly improving radiation gain, and retaining ultra-wideband performance at the same time. It is difficult to balance these three factors simultaneously, which is also a problem that needs to be solved in the design of compact high-gain Vivaldi antennas at this stage. There is a lack of standardized and comprehensive solutions. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, a comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna with loaded metasurface and its configuration method are provided to solve the above problems.

[0004] A high-gain ultrawideband Vivaldi antenna with a metasurface-loaded comb-like sawtooth pattern includes a substrate, a main patch, and multiple top radiating patches. The main patch and the multiple top radiating patches are all fixedly attached to one side of the substrate. An exponentially graded groove is machined at the top of the main patch, and the multiple top radiating patches are arranged within the exponentially graded groove. A recessed graded structure is machined on each side of the main patch, and the recessed graded structure includes multiple sawtooth-shaped current-damping grooves and multiple curved strip-shaped notches. From top to bottom, each side of the main patch has multiple sawtooth-shaped current-damping grooves and multiple... The main patch features multiple curved strip-shaped notches and serrated flow-damping grooves arranged side-by-side. Each serrated flow-damping groove is positioned near the top of the main patch, and each curved strip-shaped notch is positioned near the bottom of the main patch. A comb-shaped curved flow arm is formed between two adjacent curved strip-shaped notches. From top to bottom, the bottom of the main patch is machined with a strip-shaped groove and a circular feed groove. The length direction of the strip-shaped groove is the same as the length direction of the main patch. One end of the strip-shaped groove is connected to the small end of the exponential gradient groove, and the other end of the strip-shaped groove is connected to the circular feed groove.

[0005] As a preferred embodiment: the exponential gradient groove is a conical notch, the inner wall of the exponential gradient groove is curved, the length direction of the exponential gradient groove is in the same direction as the thickness direction of the substrate, and the width of the large opening of the exponential gradient groove is set to match three-quarters of the width of the substrate.

[0006] As a preferred embodiment: each top radiating patch is a refractive lens, and each top radiating patch includes an upper arc-shaped piece, a middle arc-shaped piece, a lower arc-shaped piece, and a metal connecting arm. The upper arc-shaped piece, the middle arc-shaped piece, and the lower arc-shaped piece are arranged coaxially from top to bottom. The length of the lower arc-shaped piece is less than the length of the middle arc-shaped piece, and the length of the middle arc-shaped piece is less than the length of the upper arc-shaped piece. The upper arc-shaped piece, the middle arc-shaped piece, and the lower arc-shaped piece are vertically connected by a metal connecting arm, which is connected to the middle part of the upper arc-shaped piece, the middle part of the middle arc-shaped piece, and the middle part of the lower arc-shaped piece, respectively.

[0007] As a preferred option, the range of the circular angle corresponding to the upper arc-shaped sheet is 15~30 degrees.

[0008] As a preferred embodiment: a transmission plate is provided on the other side of the substrate. The transmission plate includes a conical strip and a circular plate. The circular plate is fixedly attached to the other side of the substrate. The length direction of the conical strip is in the same direction as the width direction of the substrate. The small end of the conical strip is fixedly connected to the circular plate as a whole. The large end of the conical strip is flush with the edge of the substrate side that is close to it.

[0009] As a preferred option, the reference characteristic data of the comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna with loaded metasurface include the substrate length L, substrate width W, width W1 of the large end of the exponentially graded groove, radius R1 of the circular sheet, radius R2 of the circular feed groove, and growth rate R of the exponentially graded groove.

[0010] A method for configuring a comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna with a loaded metasurface is disclosed. This method involves calculating the antenna's curvature and minimum operating frequency based on predetermined baseline characteristic data of the comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna. Then, simulation testing and optimization are performed based on the antenna's curvature and minimum operating frequency to obtain a simulated maximum gain of 12.5 dB for the comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna.

[0011] As a preferred option: the calculation process for obtaining the antenna curvature and minimum operating frequency based on the predetermined reference characteristic data of the comb-shaped sawtooth high-gain ultra-wideband Vivaldi antenna using formulas one, two, and three is as follows:

[0012]

[0013]

[0014]

[0015] In the above formula, Let R be the curvature of the antenna, and R be the growth rate of the exponentially tapered groove. P1(x1,y1) and P2(x2,y2) are the initial and final coordinates of the comb-shaped curved arm, respectively. The process coefficients C1 and C2 are calculated from the reference characteristic data. The curvature of the antenna is obtained through the above calculations. The minimum operating frequency of the antenna is calculated by using the substrate length L, substrate width W, and the width W1 of the large end of the exponentially tapered groove from the reference feature data.

[0016] As a preferred option: based on the curvature of the antenna An initial model was constructed based on the lowest operating frequency of the antenna. After optimizing and simulating the antenna's geometric parameters using high-frequency three-dimensional electromagnetic field simulation software, the maximum gain of the loaded metasurface comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna was obtained when the substrate length L, substrate width W, and the width W1 of the large end of the exponentially tapered groove were at their minimum values ​​in the reference feature data.

[0017] The beneficial effects of this invention are as follows:

[0018] The comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna of this invention achieves a balance between small size and high gain through the interaction of a substrate, main patch, top radiating patch, exponentially tapered groove, sawtooth-shaped flow-damping groove, curved strip-shaped notch, strip-shaped groove body, circular feed groove, and comb-shaped curved arms. The comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna of this invention successfully extends the lower limit of its operating frequency band from 3.4 GHz to 2.5 GHz, achieving effective low-frequency extension. Through optimized aperture field distribution, the antenna of this invention achieves a simulated maximum gain of 12.5 dB, a maximum improvement of approximately 2.5 dB, and maintains stable radiation in the 2.5–12 GHz ultrawideband range.

[0019] The configuration method of the comb-tooth high-gain ultra-wideband Vivaldi antenna with loaded metasurface in this invention can realize the process of obtaining the antenna curvature and minimum operating frequency by calculating the reference characteristic data of the comb-tooth high-gain ultra-wideband Vivaldi antenna according to the predetermined reference characteristic data of the comb-tooth high-gain ultra-wideband Vivaldi antenna, and then performing simulation test optimization based on the antenna curvature and minimum operating frequency to obtain a comb-tooth high-gain ultra-wideband Vivaldi antenna with a simulated maximum gain of 12.5dB. By forming a configuration process with the maximum limit gain under a fixed size corresponding to the predetermined data requirements, a processing method that takes into account both standardized size and gain balance is formed, providing accurate data for subsequent processing and accurate data conditions for gain prediction under the predetermined size. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the first three-dimensional structure of the comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna with a loaded metasurface in this invention. The figure shows a side of the substrate with a patch and a top radiating patch.

[0021] Figure 2 This is a schematic diagram of the second three-dimensional structure of the comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna with a loaded metasurface in this invention. The figure shows a side of the substrate with a patch and a top radiating patch.

[0022] Figure 3This is a rear-view three-dimensional structural diagram of the comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna with a loaded metasurface in this invention, showing the other side of the substrate.

[0023] Figure 4 This is a schematic diagram of the three-dimensional structure of the transmission sheet on the substrate.

[0024] Figure 5 A front view schematic diagram showing the relative positional relationship between the substrate, the transmission sheet, and the exponentially gradient groove;

[0025] Figure 6 A front view schematic diagram showing the relative positional relationship between the substrate, the transport sheet, the comb-shaped curved arm, and the exponentially gradient groove;

[0026] Figure 7 This is a schematic diagram showing the marked positions of the reference feature data on the antenna.

[0027] Figure 8 For simulation S 11 A schematic diagram of the CVA curve;

[0028] Figure 9 For simulation S 11 A schematic diagram of the curve of EVA in China;

[0029] Figure 10 For simulation S 11 A schematic diagram of the SEVA curve;

[0030] Figure 11 This is a schematic diagram of the surface current distribution of a CVA at 3 GHz.

[0031] Figure 12 This is a schematic diagram of the surface current distribution of EVA at 3GHz;

[0032] Figure 13 This is a schematic diagram of the surface current distribution of EVA at 12GHz;

[0033] Figure 14 This is a schematic diagram of the surface current distribution of SEVA at 12 GHz;

[0034] Figure 15 A schematic diagram showing the comparison of simulation gain results for CVA, EVA, and SEVA;

[0035] Figure 16 This is a schematic diagram of the main structure of the top radiating patch;

[0036] Figure 17 This is a schematic diagram of the boundary conditions for the top radiating patch;

[0037] Figure 18 A graph showing the S-parameters of the top radiating patch;

[0038] Figure 19 A graph showing the normalized impedance of the top radiating patch;

[0039] Figure 20 The graph shows the equivalent permittivity versus equivalent permeability of the top radiating patch.

[0040] Figure 21 A graph showing the equivalent refractive index of the top radiating patch;

[0041] Figure 22 The electric field distribution of the top radiating patch at 12 GHz;

[0042] Figure 23 This is a schematic diagram of the main structure of MSEVA;

[0043] Figure 24 A schematic diagram of the S11 parameters of MSEVA;

[0044] Figure 25 A schematic diagram of electromagnetic wave propagation at the interface between the top radiating patch and the air.

[0045] Figure 26 This is a schematic diagram of the E-plane of the antenna in this invention at 12GHz;

[0046] Figure 27 This is a schematic diagram of the H-plane of the antenna in this invention at 12GHz;

[0047] Figure 28 This is a schematic diagram of the electric field distribution of SEVA;

[0048] Figure 29 This is a schematic diagram of the electric field distribution of MSEVA;

[0049] Figure 30 A comparative gain diagram showing the differences between CVA, EVA, SEVA, and MSEVA;

[0050] Figure 31 This is a schematic diagram of the first test of the antenna in the microwave anechoic chamber of the present invention;

[0051] Figure 32 This is a schematic diagram of the second test of the antenna in the microwave anechoic chamber of the present invention;

[0052] Figure 33 This is a schematic diagram comparing the MSEVA measurement and simulation S11 curves.

[0053] Figure 34 This is a schematic diagram showing the comparison curves of MSEVA measurement and simulation gain.

[0054] Figure 35 This is a schematic diagram of the E-plane of SEVA at 2 GHz;

[0055] Figure 36 This is a schematic diagram of the H-plane of SEVA at 2 GHz.

[0056] In the figure: 1-substrate; 2-main patch; 3-top radiating patch; 3-1-upper arc-shaped plate; 3-2-middle arc-shaped plate; 3-3-lower arc-shaped plate; 3-4-metal connecting arm; 4-exponential gradient groove; 5-serrated flow-stopping groove; 6-curved strip-shaped notch; 7-strip-shaped groove; 8-circular feed groove; 9-transmission plate; 9-1-conical strip; 9-2-circular plate; 10-comb-shaped curved flow arm. Detailed Implementation

[0057] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0058] Specific implementation method one: Combining Figures 1 to 36 This embodiment describes a high-gain ultrawideband Vivaldi antenna with a metasurface-loaded comb-like sawtooth pattern. The antenna includes a substrate 1, a main patch 2, and multiple top radiating patches 3. The main patch 2 and the multiple top radiating patches 3 are fixedly attached to one side of the substrate 1. An exponentially tapered groove 4 is machined at the top of the main patch 2, and the multiple top radiating patches 3 are arranged within the exponentially tapered groove 4. A recessed tapered structure is machined on each side of the main patch 2. The recessed tapered structure includes multiple sawtooth-shaped current-damping grooves 5 and multiple curved strip-shaped notches 6. Multiple sawtooth-shaped current-damping grooves are machined from top to bottom on each side of the main patch 2. 5 and multiple curved strip-shaped notches 6, multiple sawtooth-shaped flow-blocking grooves 5 are arranged side by side, multiple curved strip-shaped notches 6 are arranged side by side, each sawtooth-shaped flow-blocking groove 5 is located near the top of the main patch 2, each curved strip-shaped notch 6 is located near the bottom of the main patch 2, and a comb-shaped curved flow arm 10 is formed between two adjacent curved strip-shaped notches 6; the bottom end of the main patch 2 is sequentially machined with strip-shaped grooves 7 and circular feed grooves 8 from top to bottom, the length direction of the strip-shaped grooves 7 is in the same direction as the length direction of the main patch 2, one end of the strip-shaped grooves 7 is connected to the small end of the exponential gradient groove 4, and the other end of the strip-shaped grooves 7 is connected to the circular feed groove 8.

[0059] In this embodiment, multiple top radiating patches 3 form a multi-point matrix group, arranged in an inverted triangular overall configuration within an exponentially gradient groove 4. One arrangement most conducive to achieving small size and high gain is four rows, with each row increasing in number from bottom to top by 2 to 3 top radiating patches 3. The first row contains only one top radiating patch 3. The number of rows and the number of patches per row are determined according to predetermined baseline characteristic data requirements, ensuring a proper match between the refraction requirements and the refraction area of ​​the multi-point matrix group.

[0060] Specific Implementation Method Two: This implementation method is a further limitation of Specific Implementation Method One. In this implementation method, the exponential gradient groove 4 is a conical notch, the inner wall of the exponential gradient groove 4 is curved, the length direction of the exponential gradient groove 4 is in the same direction as the thickness direction of the substrate 1, and the width of the large opening of the exponential gradient groove 4 is set to match three-quarters of the width of the substrate 1.

[0061] Specific Implementation Method 3: This implementation method is a further limitation of Specific Implementation Method 1 or 2. In this implementation method, each top radiating patch 3 is a refractive lens. Each top radiating patch 3 includes an upper arc-shaped plate 3-1, a middle arc-shaped plate 3-2, a lower arc-shaped plate 3-3, and a metal connecting arm 3-4. The upper arc-shaped plate 3-1, the middle arc-shaped plate 3-2, and the lower arc-shaped plate 3-3 are coaxially arranged from top to bottom. The length of the arc-shaped piece 3-3 is less than the length of the middle arc-shaped piece 3-2, and the length of the middle arc-shaped piece 3-2 is less than the length of the upper arc-shaped piece 3-1. A metal connecting arm 3-4 is vertically connected between the upper arc-shaped piece 3-1, the middle arc-shaped piece 3-2, and the lower arc-shaped piece 3-3. The metal connecting arm 3-4 is connected to the middle part of the upper arc-shaped piece 3-1, the middle part of the middle arc-shaped piece 3-2, and the middle part of the lower arc-shaped piece 3-3, respectively.

[0062] Specific Implementation Method Four: This implementation method is a further limitation of Specific Implementation Method One, Two or Three. In this implementation method, the value range of the circular angle corresponding to the upper arc-shaped piece 3-1 is 15~30 degrees.

[0063] Specific Implementation Method 5: This implementation method is a further limitation of Specific Implementation Methods 1, 2, 3 or 4. In this implementation method, a transmission plate 9 is provided on the other side of the substrate 1. The transmission plate 9 includes a conical strip 9-1 and a circular plate 9-2. The circular plate 9-2 is fixedly attached to the other side of the substrate 1. The length direction of the conical strip 9-1 is in the same direction as the width direction of the substrate 1. The small end of the conical strip 9-1 is fixedly connected to the circular plate 9-2 as a whole. The large end of the conical strip 9-1 is flush with the edge of the side of the substrate 1 that is close to it.

[0064] In this embodiment, the circular power supply slot 8 and the circular sheet 9-2 are not coaxially arranged and are respectively disposed on both sides of the substrate 1.

[0065] Specific Implementation Method Six: This implementation method is a further limitation of Specific Implementation Method One, Two, Three, Four or Five. In this implementation method, the reference characteristic data of the comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna with loaded metasurface includes the length L of substrate 1, the width W of substrate 1, the width W1 of the large end of the exponentially graded groove 4, the radius R1 of the circular sheet 9-2, the radius R2 of the circular feed groove, and the growth rate R of the exponentially graded groove 4.

[0066] In this embodiment, the reference feature data also includes the width L1 of the large end of the conical strip 9-1, the width L2 of the metal connecting arm 3-4, the vertical width L3 of the curved strip notch 6, the width L4 of the large end of the serrated flow-damping groove 5 and the vertical width L5 between two adjacent curved strip notches 6, and the opening half angle θ of the exponential gradient groove 4.

[0067] By using the above-mentioned cone-shaped strip 9-1 with a large end width of L1, metal connecting arm 3-4 with a width of L2, curved strip notch 6 with a vertical width of L3, sawtooth flow-damping groove 5 with a large end width of L4 and vertical width between two adjacent curved strip notches 6 with a vertical width of L5, and the opening half angle θ of exponentially tapered groove 4, the antenna model can be obtained more accurately.

[0068] Combination Figures 5 to 7 As shown, in this embodiment, the opening half angle θ of the exponential gradient groove 4 is half the opening angle of the exponential gradient groove 4, and it is also the angle between the hypotenuse of the sawtooth flow-damping groove 5 and the vertical center line of the antenna, that is, one dashed line is vertically downward and the other is attached to the hypotenuse of the yellow metal, and the acute angle formed by the two lines.

[0069] The opening half-angle θ directly determines the opening speed of the antenna slot and the overall horn expansion shape.

[0070] A larger opening angle θ corresponds to a steeper opening on both sides of the antenna and a wider horn-like opening; a smaller opening angle θ corresponds to a flatter opening on both sides of the antenna and a narrower and more elongated overall shape.

[0071] Furthermore, the opening half-angle θ is strongly correlated with the antenna's lowest operating frequency and high-frequency cutoff frequency. The opening half-angle θ determines the overall outline of the antenna, the horn opening angle, and the overall shape trend.

[0072] The radius R1 of the circular plate 9-2 and the radius R2 of the circular feed groove determine the curvature and radius of the comb-shaped curved arm 10.

[0073] Specific implementation method seven: Combination Figures 1 to 36This embodiment describes the configuration method of the comb-sawtooth high-gain ultra-wideband Vivaldi antenna with loaded metasurface. This involves calculating the antenna curvature and minimum operating frequency based on predetermined reference characteristic data of the comb-sawtooth high-gain ultra-wideband Vivaldi antenna, and then performing simulation tests and optimizations based on the antenna curvature and minimum operating frequency to obtain a simulated maximum gain of 12.5 dB for the comb-sawtooth high-gain ultra-wideband Vivaldi antenna. Other antenna structures and connection relationships not mentioned are the same as in specific embodiments one, two, three, four, five, or six.

[0074] Specific Implementation Method Eight: This implementation method is a further limitation of Specific Implementation Method Seven. In this implementation method, the calculation process for obtaining the antenna curvature and minimum operating frequency based on the predetermined reference characteristic data of the comb-shaped sawtooth high-gain ultra-wideband Vivaldi antenna using formulas one, two, and three is as follows:

[0075]

[0076]

[0077]

[0078] In the above formula, Let R be the curvature of the antenna, and R be the growth rate of the exponentially tapered groove 4. P1(x1,y1) and P2(x2,y2) are the initial and final coordinates of the comb-shaped curved arm 10, respectively. The process coefficients C1 and C2 are calculated from the reference characteristic data. The curvature of the antenna is obtained through the above calculations. The minimum operating frequency of the antenna is calculated using the length L of substrate 1, the width W of substrate 1, and the width W1 of the large end of the exponentially tapered groove 4 from the reference feature data. In specific processing, R is 0.06, and C1 and C2 are 11.1 and -1.58, respectively.

[0079] The reference characteristic data of the comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna with loaded metasurface in this embodiment include the length L of substrate 1, the width W of substrate 1, the width W1 of the large end of the exponentially graded groove 4, the radius R1 of the circular sheet 9-2, the radius R2 of the circular feed groove, and the growth rate R of the exponentially graded groove 4.

[0080] In this embodiment, the reference feature data also includes the width L1 of the large end of the conical strip 9-1, the width L2 of the metal connecting arm 3-4, the vertical width L3 of the curved strip notch 6, the width L4 of the large end of the serrated flow-damping groove 5 and the vertical width L5 between two adjacent curved strip notches 6, and the opening half angle θ of the exponential gradient groove 4.

[0081] In this embodiment, the overall length and width dimensions of the core arithmetic antenna are used to calculate the minimum operating frequency. The radius R1 of the circular plate 9-2, the radius R2 of the circular feed slot, and the radius corresponding to the curved strip notch 6 are used to calculate the curve curvature or are obtained through the above calculation formula. The opening tilt angle of the exponentially tapered slot 4 controls the overall expansion shape, bandwidth characteristics, feed, top detail dimensions of the feed structure, and antenna end structure of the antenna. Other unmentioned contents are the same as those in specific embodiments one, two, three, four, five, six, or seven.

[0082] Specific Implementation Method Nine: This implementation method is a further limitation of Specific Implementation Method Eight. In this implementation method, the curvature of the antenna is considered. An initial model was constructed based on the lowest operating frequency of the antenna. After optimizing and simulating the antenna's geometric parameters using high-frequency three-dimensional electromagnetic field simulation software, the maximum gain of the loaded metasurface comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna was obtained when the length L of substrate 1, the width W of substrate 1, and the width W1 of the large aperture of the exponentially tapered groove 4 were at their minimum values ​​in the reference feature data.

[0083] The antenna in this invention is a miniaturized high-gain MSEVA antenna structure. Specifically, the optimal parameters are that the antenna operates in an ultra-wideband frequency range of 2.5-12 GHz, is manufactured on a Rogers 4350B substrate, has a dielectric constant of 3.48, and overall dimensions of 40 mm × 50 mm × 0.762 mm. , The wavelength in free space corresponds to the lowest operating frequency. This invention achieves performance improvement through a three-step optimization method: First, by loading a comb-like curved arm structure to optimize impedance matching, the lowest operating frequency is extended from 3.4 GHz to 2.5 GHz, achieving miniaturization and improving low-frequency radiation, i.e., the transitional EVA structure is formed; second, a uniformly arranged sawtooth-shaped deflector structure is designed to optimize the aperture field distribution and improve gain, i.e., the transitional SEVA structure is formed; finally, a metasurface lens is integrated to further focus the beam; ultimately, the MSEVA achieves a simulated maximum gain of 12.5 dB and a measured maximum gain of 11.1 dB in an electrically small size. Experimental verification shows that the antenna simulation and experimental results are in good agreement, and the radiation characteristics are good within the main operating frequency band.

[0084] Combination Figure 5 , Figure 6 and Figure 7 As shown, in the specific formation process of the antenna in this invention, the optimal parameter configuration is to use a conventional coplanar Vivaldi antenna with a standard exponentially tapered groove line, i.e., the performance of the CVA antenna, as a performance benchmark. This is achieved by etching a comb-shaped curved arm 10 with a growth rate of 0.235, consisting of symmetrical exponential curves, onto the top radiating patch 3. Figure 6The improved antenna EVA shown here extends the surface current path, expands the low-frequency cutoff frequency, and slightly improves the low-frequency gain without increasing the size.

[0085] Combination Figure 7 The diagram further illustrates the etching of sawtooth-shaped flow-damping grooves 5 at the EVA aperture, which are composed of symmetrical exponential curves with a growth rate of 0.24. The overall structure is rotated outwards by 66° relative to the normal to obtain SEVA, used to optimize mid-to-high frequency gain. The antenna of this invention consists of a front-loaded comb-shaped curved arm 10, a top radiating patch 3 with sawtooth-shaped flow-damping grooves 5, and a back microstrip feeding structure. Specifically, the microstrip feeding structure is a transmission plate 9. The substrate 1 is a dielectric substrate, specifically a Rogers 4350B, with a thickness of 0.762 mm, a dielectric constant of 3.48, and a copper foil thickness of 0.035 mm. The excitation method uses a 50-ohm wave port.

[0086] Specific Implementation Method Ten: This implementation method is a further limitation of Specific Implementation Methods Seven, Eight, or Nine. In the implementation process, the configuration method in this implementation method, combined with specific calculation steps and actual conditions, uses CST Microwave Studio as the high-frequency three-dimensional electromagnetic field simulation software. The antenna geometric parameters are optimized and simulated using the high-frequency three-dimensional electromagnetic field simulation software, and the final parameters are shown in Table 1 below:

[0087] Table 1 Antenna Geometric Parameters

[0088] Combination Figures 8 to 14 As shown in this embodiment, the CVA exhibits an S11 < -10dB within the 3.3-12.0GHz frequency range, with a minimum operating frequency of 3.3GHz. By extending the edge current path with the comb-shaped curved arm 10 and lowering the cutoff frequency, the minimum operating frequency of the EVA is extended to 2.5GHz, achieving miniaturization. Even after loading the sawtooth-shaped current-damping groove 5, the minimum operating frequency of the SEVA remains at 2.5GHz, indicating that this structure has no significant impact on the operating bandwidth. At 3GHz, the surface current distribution with the comb-shaped curved arm 10 shows that the EVA surface current path is extended, effectively reducing echo and extending the low-frequency bandwidth.

[0089] Building upon EVA, the next step is to introduce a sawtooth-shaped current-deflecting groove design (SEVA) to optimize the antenna aperture field distribution. This causes electromagnetic waves to converge in the end-firing direction, thereby improving antenna gain. Figure 13 and Figure 14 As shown, the surface current distribution of EVA and SEVA at 12GHz is analyzed. After loading the sawtooth current-blocking groove, the current distribution is concentrated at the sawtooth structure, which gathers the high-frequency electromagnetic field and reduces the return loss.

[0090] Combination Figure 15As shown, SEVA improves the gain by approximately 0.2-1.9 dB compared to CVA in the 2.5-12 GHz band, but the gain decreases in the 9-10 GHz band due to the disruption of surface current distribution caused by the etched curved arms and choke groove structure. Subsequent studies will introduce metasurface MSEVA to improve high-frequency gain.

[0091] The top radiating patch 3 in this invention is essentially a third-order arc-shaped arm metasurface structure, configured to increase the lens surface, combined with... Figure 16 and Figure 17 As shown, it consists of three arc-shaped structures and a vertical metal arm. Each top radiating patch 3 includes an upper arc-shaped sheet 3-1, a middle arc-shaped sheet 3-2, a lower arc-shaped sheet 3-3, and a metal connecting arm 3-4. A 5mm × 5mm × 0.762mm region is etched in the exponentially graded groove 4, with a copper foil thickness of 0.035mm. During simulation analysis, PEC and PMC type boundary conditions are applied at the volume boundary. The PEC boundary is perpendicular to the incident electric field direction, and the PMC boundary is perpendicular to the incident magnetic field direction. Detailed parameters of the metasurface unit are shown in Table 2 below.

[0092] Table 2 Metasurface Geometric Parameters

[0093] The metasurface unit was simulated in the full-wave simulation software CST Microwave Studio.

[0094] Combination Figures 18 to 21 As shown, this displays scattering parameters and the refractive index of the extracted metasurface unit. (From...) Figure 18 Simulated S-parameter plots show the S-parameters of this unit in the 2.5-12 GHz range. 11 Less than -15dB, the frequency range fully covers the operating frequency band of the designed SEVA. 21 The value is close to 0, indicating that the reflection loss of the designed metasurface unit is negligible. Figure 21 The equivalent refractive index is slightly greater than 1.8 and remains stable in the 2.5-12 GHz range.

[0095] The normalized impedance Zeff and effective refractive index neff can be extracted from the S-parameters using effective dielectric theory. The curved structure of the metasurface has a significant impact on both the S-parameters and the equivalent dielectric constant: increasing the size of the curved section enhances the dielectric constant but degrades the S21 transmission coefficient of the metasurface unit and increases losses; decreasing the size produces a similar effect. These parameters need to be properly tuned to achieve the desired characteristics in the target frequency band.

[0096] The refractive index is determined by the equivalent dielectric constant. and permeability We obtain . are the equivalent permittivity and permeability of the metasurface unit, respectively, calculated using the following formula:

[0097]

[0098] Combination Figure 22 As shown, at a frequency of 12 GHz, the electric field distribution of the metasurface unit is concentrated at the two edges of the arc-shaped structure. When electromagnetic waves are incident on the conductor surface, regions with opposite charges are generated at the arc-shaped structure. The accumulated charges effectively form a periodic array of electric dipoles on the metasurface, enabling it to form an effective dielectric constant in the corresponding frequency band of the operating frequency.

[0099] Combination Figure 23 As shown, based on SEVA, the dielectric substrate is extended by 5mm, and a metasurface lens is integrated in the end-emitting direction to form MSEVA. At this time, the lens can focus the beam and effectively enhance the directional radiation capability and gain of the high-frequency band above 11GHz.

[0100] Combination Figure 24 As shown, the lowest cutoff frequency of MSEVA's S11 parameters is 2.5 GHz, indicating that metasurface loading has no significant impact on the operating bandwidth. The periods are P1 = 4 mm and P2 = 4.009 mm.

[0101] Combination Figure 25 As shown, the schematic diagram of electromagnetic wave propagation between the lens and the air interface is shown. The relationship between wave refraction at the two interfaces is explained by the following formula. Combined with formula (5), it is calculated that when n1 is greater than n0, the refraction angle θ0 in the air is greater than the incident angle θ1 in the lens, and the electric field is concentrated at the center of the antenna aperture, thereby improving the directivity and gain of the antenna.

[0102]

[0103] Combination Figures 26 to 30 As shown, at 12 GHz, the E-plane and H-plane beamwidths of MSEVA are narrower than those of SEVA, the sidelobe level is reduced, and the antenna gain and directivity are improved.

[0104] Combination Figure 28 and Figure 29 As shown, the electric field converges more towards the center after loading the metasurface lens. MSEVA improves the gain by up to 2.5dB compared to CVA, but there is a 0.1-0.3dB drop in the 3-5.5GHz range, which is due to the comb-shaped curved arms and sawtooth-shaped current-damping grooves disrupting the surface current distribution.

[0105] Combination Figures 31 to 32 As shown, in the sample testing process of this invention, MSEVA was fabricated according to simulation parameters, and the measured S was displayed in a microwave anechoic chamber. 11 A comparison with simulation results shows that the measured return loss in the 2.5-12 GHz operating frequency band follows the same trend as the simulation. However, at 2.9 GHz, S...11 The value was -9.8dB, caused by the welding of the SMA connector disrupting the current distribution on the antenna surface and by manufacturing errors. (This is achieved through...) Figure 32 As can be seen from the comparison between the measured and simulated antenna gain in this invention, the maximum measured gain is 11.1 dB, and the gain trend is basically consistent with the simulation, verifying the reliability and effectiveness of this invention in actual use.

[0106] Combination Figures 34 to 36 As can be seen from the E-plane and H-plane radiation patterns of MSEVA at 6 GHz, 9 GHz, and 12 GHz, the performance verification process through the comparison of simulation and experimental results is evident. Specifically, at 6 GHz, the simulated and experimental curves show a high degree of consistency in the main beam pointing direction for both the E-plane and H-plane, although the experimental beamwidth is slightly wider and there are subtle differences in sidelobe characteristics. Similarly, at 9 GHz and 12 GHz, the overall trends of the simulated and experimental curves are basically consistent, but some obvious deviations can be observed in details, such as the sidelobe level in the H-plane and the main beam shape. Overall, this demonstrates the correctness of the design in terms of main radiation characteristics and reflects the unavoidable influence of factors such as manufacturing tolerances and multipath reflections in the actual testing environment.

[0107] This invention addresses the challenge of balancing miniaturization and high gain in traditional Vivaldi antennas by employing a composite loading strategy that integrates comb-shaped curved arms, sawtooth-shaped flow deflectors, and artificial metasurfaces. This effectively extends low-frequency performance and enhances radiation performance within the 2.5–12 GHz band. The antenna is compact, and simulation and experimental results agree well, validating the design's effectiveness and providing a feasible path for miniaturized, high-gain Vivaldi antenna design.

[0108] Table 3. Parameter Comparison between the Invention and Existing Antennas

[0109] A detailed analysis of the key performance parameters of the antenna in Table 3 above shows that this invention achieves an absolute bandwidth exceeding 9 GHz within a limited space of only 40 mm × 50 mm × 0.762 mm, with significantly improved gain characteristics: the simulated maximum gain reaches 12.5 dB, and the measured maximum gain is 11.1 dB. Table 3, comparing this invention with eight other existing antennas, shows that this invention achieves the best balance in terms of mutually constraining indicators such as electrical size, impedance bandwidth, and peak gain, exhibiting superior overall performance compared to most similar antennas, highlighting the advantages of the composite loading method. Research confirms the effectiveness of the synergistic design of the comb-shaped curved arm, sawtooth-shaped flow-damping groove, and metasurface lens, providing a reliable solution for realizing high-performance ultra-wideband antennas within limited space, and demonstrating application potential in ultra-wideband communication, radar imaging, and portable devices.

Claims

1. A comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna with a loaded metasurface, characterized in that: The system includes a substrate (1), a main patch (2), and multiple top radiating patches (3). The main patch (2) and the multiple top radiating patches (3) are fixedly attached to one side of the substrate (1). The top of the main patch (2) is processed with an exponential gradient groove (4), and the multiple top radiating patches (3) are arranged in the exponential gradient groove (4). A recessed gradient structure is processed on both sides of the main patch (2). The recessed gradient structure includes multiple sawtooth flow-blocking grooves (5) and multiple curved strip-shaped notches (6). Each side of the main patch (2) is processed from top to bottom with multiple sawtooth flow-blocking grooves (5) and multiple curved strip-shaped notches (6). The multiple sawtooth flow-blocking grooves (5) and multiple curved strip-shaped notches (6) are processed on each side of the main patch (2) from top to bottom. 5) are arranged side by side, and multiple curved strip-shaped notches (6) are arranged side by side. Each sawtooth flow-blocking groove (5) is located near the top of the main patch (2), and each curved strip-shaped notch (6) is located near the bottom of the main patch (2). A comb-shaped curved flow arm (10) is formed between two adjacent curved strip-shaped notches (6). The bottom end of the main patch (2) is processed with a strip-shaped groove (7) and a circular feed groove (8) from top to bottom. The length direction of the strip-shaped groove (7) is the same as the length direction of the main patch (2). One end of the strip-shaped groove (7) is connected to the small end of the exponential gradient groove (4), and the other end of the strip-shaped groove (7) is connected to the circular feed groove (8).

2. The Vivaldi antenna with a loaded metasurface and comb-like sawtooth pattern, high gain, ultrawideband, according to claim 1, is characterized in that: The exponential gradient groove (4) is a conical notch. The inner wall of the exponential gradient groove (4) is curved. The length direction of the exponential gradient groove (4) is in the same direction as the thickness direction of the substrate (1). The width of the large opening of the exponential gradient groove (4) is set to match three-quarters of the width of the substrate (1).

3. The high-gain ultrawideband Vivaldi antenna with a loaded metasurface and serrated edges according to claim 1 or 2, characterized in that: Each top radiating patch (3) is a refractive lens. Each top radiating patch (3) includes an upper arc-shaped plate (3-1), a middle arc-shaped plate (3-2), a lower arc-shaped plate (3-3), and a metal connecting arm (3-4). The upper arc-shaped plate (3-1), the middle arc-shaped plate (3-2), and the lower arc-shaped plate (3-3) are arranged coaxially from top to bottom. The length of the lower arc-shaped plate (3-3) is less than that of the middle arc-shaped plate (3-4). 3-2) Length: The length of the middle arc-shaped piece (3-2) is less than the length of the upper arc-shaped piece (3-1). The upper arc-shaped piece (3-1), the middle arc-shaped piece (3-2), and the lower arc-shaped piece (3-3) are vertically connected by a metal connecting arm (3-4). The metal connecting arm (3-4) is connected to the middle part of the upper arc-shaped piece (3-1), the middle part of the middle arc-shaped piece (3-2), and the middle part of the lower arc-shaped piece (3-3), respectively.

4. The high-gain ultrawideband Vivaldi antenna with a loaded metasurface and serrated edges according to claim 3, characterized in that: The range of the circular angle corresponding to the upper arc-shaped piece (3-1) is 15~30 degrees.

5. The high-gain ultrawideband Vivaldi antenna with a loaded metasurface and comb-like sawtooth pattern according to claim 4, characterized in that: A transmission plate (9) is provided on the other side of the substrate (1). The transmission plate (9) includes a conical strip (9-1) and a circular plate (9-2). The circular plate (9-2) is fixedly attached to the other side of the substrate (1). The length direction of the conical strip (9-1) is in the same direction as the width direction of the substrate (1). The small end of the conical strip (9-1) is fixedly connected to the circular plate (9-2) as a whole. The large end of the conical strip (9-1) is flush with the edge of the side of the substrate (1) it is close to.

6. The high-gain ultrawideband Vivaldi antenna with a loaded metasurface and comb-like sawtooth pattern according to claim 5, characterized in that: The reference characteristic data of the comb-tooth high-gain ultrawideband Vivaldi antenna with loaded metasurface include the length L of the substrate (1), the width W of the substrate (1), the width W1 of the large end of the exponentially graded groove (4), the radius R1 of the circular sheet (9-2), the radius R2 of the circular feed groove, and the growth rate R of the exponentially graded groove (4).

7. A method for configuring a high-gain ultrawideband Vivaldi antenna with a metasurface-loaded comb-shaped sawtooth pattern, as described in any one of claims 1 to 6, characterized in that: The configuration method for the comb-tooth high-gain ultra-wideband Vivaldi antenna involves calculating the antenna's curvature and minimum operating frequency based on predetermined baseline characteristic data of the comb-tooth high-gain ultra-wideband Vivaldi antenna, and then performing simulation tests and optimizations based on the antenna's curvature and minimum operating frequency to obtain a simulated maximum gain of 12.5 dB for the comb-tooth high-gain ultra-wideband Vivaldi antenna.

8. The configuration method of the comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna with loaded metasurface according to claim 7, characterized in that: The calculation process for obtaining the antenna curvature and minimum operating frequency based on the predetermined reference characteristic data of the comb-shaped sawtooth high-gain ultra-wideband Vivaldi antenna using formulas one, two, and three is as follows: ， ， ， In the above formula, R is the curvature of the antenna, and R is the growth rate of the exponentially tapered groove (4); P1(x1,y1) and P2(x2,y2) are the initial and final coordinates of the comb-shaped curved arm (10), respectively. The process coefficients C1 and C2 are calculated from the reference feature data. The curvature of the antenna is obtained through the above calculations. The minimum operating frequency of the antenna is calculated by using the length L of the substrate (1), the width W of the substrate (1), and the width W1 of the large end of the exponential gradient groove (4) from the reference feature data.

9. The method for configuring a comb-shaped sawtooth high-gain ultrawideband Vivaldi antenna with a loaded metasurface according to claim 7 or 8, characterized in that: Based on the curvature of the antenna An initial model was constructed based on the lowest operating frequency of the antenna. After optimizing and simulating the antenna's geometric parameters using high-frequency three-dimensional electromagnetic field simulation software, the length L of the substrate (1), the width W of the substrate (1), and the width W1 of the large end of the exponentially tapered groove (4) were obtained in the reference feature data. The maximum gain of the loaded metasurface was 12.5dB.

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