Ultra-wideband differential Vivaldi antenna with reflection-free trapped wave characteristic and continuous gain test method of ultra-wideband differential Vivaldi antenna

Abstract

The invention discloses an ultra-wideband differential Vivaldi antenna with a reflection-free notch characteristic and a continuous gain test method of the ultra-wideband differential Vivaldi antenna. The Vivaldi antenna is composed of a differential feeder line and a metasurface on the top layer, a metal ground layer on the bottom layer and an intermediate dielectric substrate layer. A gradual change flaring groove line is etched on the metal ground layer of the bottom layer, and the gradual change flaring groove line is composed of a gradual change groove line with an exponential distribution characteristic and a tail end circular open-circuit groove line. Differential mode signals can excite a traveling wave slot mode through a broadband conversion structure formed by the differential feeder lines and the gradually-changed flaring slot lines, then resonance of the whole metasurface can be excited, and non-reflection notch absorption of electromagnetic waves of a target frequency band is achieved through inherent conductor and dielectric loss during resonance of the metasurface. The continuous gain test method overcomes the defect that a broadband balun needs to be additionally designed in a traditional differential antenna gain test, and has the advantages of being simple in test process, accurate in result and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of broadband antennas, in particular to an ultra-wideband differential Vivaldi antenna with non-reflection notch characteristics and a continuous gain testing method thereof. Background Art

[0002] With the rapid development of communications technology, ultra-wideband (UWB) technology has been widely adopted in modern wireless communication systems to improve channel capacity and data transmission rates. Antennas, as the hardware foundation of wireless communication systems, sit at the interface between the "field" and the "path." Therefore, antenna performance directly impacts communication quality. Over the past two decades, civilian UWB technology has rapidly developed, occupying the 3.1 to 10.6 GHz frequency band. However, due to increasing electromagnetic spectrum congestion, this UWB frequency band overlaps with numerous narrowband communication bands, including WLAN operating at 5.15 to 5.825 GHz, WiMAX operating at 3.3 to 3.8 GHz, RFID operating near 6.1 and 6.8 GHz, and radar systems operating in the C-band (4 to 8 GHz) and X-band (7.25 to 8.4 GHz). Therefore, mitigating mutual interference between UWB and narrowband communication systems has become crucial for improving communication quality.

[0003] Currently, ultra-wideband antennas with gain-notch characteristics offer an excellent solution for mitigating interference between ultra-wideband and narrowband communication systems. To achieve a gain-notch response within a specific frequency band, a common technique involves introducing a resonant structure at the antenna feedline or radiating element. This structure then reflects electromagnetic waves near the resonant frequency back to the input, introducing a gain zero. However, the antenna is typically the last stage in the RF transmission chain, with preceding circuits including amplifiers and frequency converters. When signals within the notch stopband are reflected back to the preceding circuits, they can cause the amplifier to saturate or degrade its stability. Furthermore, when the reflected signal, along with harmonics from the local oscillator, passes through the mixer, it can generate unwanted spurious signals. To mitigate the destructive effects of reflected signals within the notch stopband, a common technique involves introducing isolation devices between the antenna and preceding circuits. However, this inevitably increases the design complexity and cost of the transmission chain. To address this issue, researchers have designed an absorptive band-stop filter integrated into the antenna feedline, thereby introducing a non-reflecting notch stopband in the antenna gain response. This approach provides a new approach to designing notch performance for ultra-wideband antennas. At the same time, since a new absorptive band-stop filter is introduced in this method, the overall integration of the antenna needs to be further improved.

[0004] Furthermore, over the past decade, differential feeding technology has been widely used in the design of RF front-ends and antenna feed lines. Research has shown that RF front-ends designed using differential feeding technology offer advantages such as low parasitic radiation, harmonic suppression, high linearity, and a wide dynamic range. Antennas designed using differential feeding technology can be directly integrated with other differential components in the RF front-end system, such as differential low-noise amplifiers, without the need for additional balun converters. This reduces system insertion loss while further improving system integration. Due to the characteristic of differential-mode signals with equal amplitude and opposite phase, the far-field radiation generated by the cross-polarization components of the antenna under differential-mode excitation cancels each other out, so differential feeding technology can also improve the antenna's cross-polarization performance to a certain extent. Therefore, designing differential ultra-wideband antennas with non-reflection notched characteristics has important application value in improving RF front-end performance and suppressing mutual interference between ultra-wideband and narrowband communication systems. Summary of the Invention

[0005] The purpose of the present invention is to provide an ultra-wideband differential Vivaldi antenna with non-reflection notch characteristics and a continuous gain test method thereof in view of the above technical background, aiming to improve the integration of the differential RF front-end while suppressing the mutual interference between the ultra-wideband communication system and the narrowband communication system, and solve the problems of traditional differential antenna testing requiring the design of additional balun converters and discontinuous gain test results.

[0006] The technical solution for achieving the objectives of the present invention is as follows: on the one hand, an ultra-wideband differential Vivaldi antenna with a reflection-free notch characteristic is provided, the antenna comprising a metal stratum and a dielectric substrate layer arranged in sequence from bottom to top, and also comprising a differential feeder and a metasurface arranged on the dielectric substrate layer; the metasurface can generate dual-mode resonance under slot mode excitation, and then utilize the inherent dielectric loss and conductor loss of the metasurface during resonance to achieve reflection-free notch absorption of electromagnetic waves in the target frequency band; a gradient flaring slot line is etched on the metal stratum to achieve ultra-wideband end-fire; the differential feeder is used to be integrated with an external differential circuit, and at the same time, forms a microstrip line-to-slot line broadband conversion structure with the gradient flaring slot line to achieve excitation of ultra-wideband end-fire and common-mode suppression.

[0007] Furthermore, the metasurface includes a plurality of split resonant ring units arranged in an array, and electromagnetic coupling links can be formed between adjacent split resonant ring units.

[0008] Furthermore, the gradient flaring slot line includes a gradient slot line with an exponential distribution characteristic, and a circular open slot line arranged along the central axis of the gradient flaring slot line and at the end of the gradient slot line; the gradient slot line is used to achieve impedance matching between the antenna input port and free space, and the circular open slot line is used to achieve unidirectional radiation of the Vivaldi antenna and improve the impedance matching performance within the ultra-wide band.

[0009] Furthermore, the gradient groove line is located within the projection of the metasurface, and the circular open groove line is located outside the projection of the metasurface.

[0010] Furthermore, the central axis of the gradually expanding groove line coincides with the projection of the central axis of the super surface.

[0011] Furthermore, the differential feeder is a structure that is symmetrical about the projection of the central axis of the tapered flared slot line, and is used to connect two input ports located on both sides of the projection of the central axis of the tapered flared slot line. At the same time, the projection of the differential feeder passes through the portion where the tapered slot line is connected to the circular open slot line and is close to the circular open slot line. The microstrip line-slot line broadband conversion structure formed by the differential feeder and the tapered flared slot line can ensure that the traveling wave slot mode is effectively excited when a differential mode signal is input, thereby exciting the metasurface to generate dual-mode resonance, realizing ultra-wideband radiation, and achieving excellent common-mode suppression.

[0012] On the other hand, a continuous gain test method for an ultra-wideband differential Vivaldi antenna is provided, the test method comprising:

[0013] Two identical ultra-wideband differential Vivaldi antennas were selected as the transmitting and receiving antennas, respectively. During the gain test, the polarization directions of the two antennas were ensured to be identical and aligned in the direction of maximum radiation. A four-port network consisting of the two ultra-wideband differential Vivaldi antennas and the spatial propagation path was then constructed.

[0014] By terminating with a broadband matching load, the arbitrary two-port scattering parameters of the four-port network are obtained using a vector network analyzer.

[0015] Based on the two-port scattering parameters, the differential mode transmission coefficient of the current spatial four-port network is obtained through balanced four-port network theory conversion;

[0016] Based on the differential mode transmission coefficient, the continuous gain of the ultra-wideband differential Vivaldi antenna is calculated according to the Friis transmission formula.

[0017] Furthermore, the calculation formula of the continuous gain of the ultra-wideband differential Vivaldi antenna is:

[0018]

[0019] Where G meas is the continuous gain of the ultra-wideband differential Vivaldi antenna, d is the distance between the receiving antenna and the transmitting antenna, P r is the input power of the transmitting antenna, P t is the receiving power of the receiving antenna, λ is the wavelength of the gain test frequency in free space, S dd21is the differential mode transmission coefficient between two ultra-wideband differential Vivaldi antennas.

[0020] Compared with the prior art, the present invention has the following significant advantages:

[0021] (1) The ultra-wideband Vivaldi antenna proposed in the present invention adopts differential feeding technology. On the one hand, it can be directly connected to the differential RF front end without the need for an additional balun converter, thereby reducing the insertion loss of the RF system and improving the system integration. On the other hand, the broadband conversion structure composed of the top-layer balanced microstrip feed line and the bottom-layer gradient flared slot line in the present invention can ensure the normal radiation of the differential mode signal while showing inherent suppression characteristics for the common-mode electromagnetic noise in the differential RF front end, which is beneficial to improving the electromagnetic compatibility capability of the differential RF front end.

[0022] (2) The traditional Vivaldi antenna has no electromagnetic structure design on the back of the metal formation, which has the disadvantage of wasting a large area of ​​circuit size. The present invention cleverly loads the metasurface on the back of the metal formation of the Vivaldi antenna, and uses the differential mode to excite the downlink wave slot mode to excite the resonance of the entire metasurface, and then uses the inherent conductor loss and dielectric loss of the entire metasurface during resonance to absorb the electromagnetic energy of the interference signal in the target frequency band to achieve a reflection-free gain notch response. Compared with the reported research results, the present invention does not need to introduce a resonant structure or filter at the antenna feed line, which improves the integration of the antenna, and the reflection-free gain notch response achieved can more thoroughly solve the adverse effects on the radio frequency link caused by spectrum overlap.

[0023] (3) Accurate gain testing has always been one of the difficulties and challenges of differential antennas. Traditional testing methods require the additional design of a broadband balun converter to provide the required differential-mode input signal. This method not only faces the challenge of broadband balun design, but also the additional loss caused by the balun converter and the impedance mismatch between the balun and the differential antenna input port, which will lead to inaccurate gain test results. To address this problem, the present invention provides a new method for continuous gain testing of ultra-wideband differential end-fire antennas. By constructing a spatial four-port network and measuring the scattering parameters of any two ports of the network and converting them to obtain the differential-mode transmission coefficient, the continuous gain of the differential antenna can be accurately calculated with the help of the Friis transmission formula. Compared with traditional differential antenna gain testing methods, this method does not require the design of a broadband balun converter and has the advantages of simple testing and accurate results.

[0024] The present invention is further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 FIG. 1 is a top view of an ultra-wideband differential Vivaldi antenna with non-reflection notch characteristics in one embodiment.

[0026] Figure 2 FIG. 1 is a side view of an ultra-wideband differential Vivaldi antenna with non-reflection notch characteristics in one embodiment.

[0027] Figure 3 A top view of a local unit of a metasurface in one embodiment.

[0028] Figure 4 A top view of the bottom layer's gradually flared groove line in one embodiment.

[0029] Figure 5 Schematic diagram of a continuous gain test method for a broadband differential end-fire antenna in one embodiment.

[0030] Figure 6 is the differential mode reflection coefficient S obtained by simulating the ultra-wideband differential Vivaldi antenna in one embodiment. dd11 Schematic diagram.

[0031] Figure 7 The E-plane and H-plane radiation patterns of the ultra-wideband differential Vivaldi antenna of the present invention obtained by simulation and testing at a typical frequency of 7.5 GHz in one embodiment are shown in FIG. Figure 7 (a) is the E-plane radiation pattern, Figure 7 (b) in the figure is the H-surface radiation pattern.

[0032] Figure 8 FIG. 1 is a gain diagram obtained by simulating and testing an ultra-wideband differential Vivaldi antenna in one embodiment. DETAILED DESCRIPTION

[0033] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary, not as limitations. Therefore, other examples of the exemplary embodiments may also include different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0035] In the description of the present invention, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0036] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0037] In one embodiment, combined Figure 1 and Figure 2 , provides an ultra-wideband differential Vivaldi antenna with a reflection-free notch characteristic, the antenna comprising a metal layer 3 and a dielectric substrate layer 5 arranged in sequence from bottom to top, and also comprising a differential feeder 1 and a metasurface 2 arranged on the dielectric substrate layer 5; the metasurface 2 can generate dual-mode resonance under slot mode excitation, and then utilize the inherent dielectric loss and conductor loss of the metasurface during resonance to achieve reflection-free notch absorption of electromagnetic waves in the target frequency band; a gradient flaring slot line 4 is etched on the metal layer 3 to achieve ultra-wideband end-fire; the differential feeder 1 is used to be integrated with an external differential circuit, and at the same time, forms a microstrip line-slot line broadband conversion structure with the gradient flaring slot line 4 to achieve excitation of ultra-wideband end-fire and common-mode suppression.

[0038] Furthermore, in one embodiment, the metasurface 2 includes a plurality of split resonant ring units 2-1 arranged in an array, and adjacent split resonant ring units 2-1 can form an electromagnetic coupling link. The array includes but is not limited to a rectangular array, a ring array, and the like.

[0039] Here, preferably, in some embodiments, the plurality of split resonant ring units 2 - 1 are arranged in a rectangular array.

[0040] Here, preferably, in some embodiments, along the same horizontal direction of the rectangular array, the opening directions of the open resonant ring units 2-1 are the same; along the vertical direction of the rectangular array, adjacent open resonant ring units 2-1 have a central rotationally symmetrical structural feature to ensure that the metasurface 2 can generate dual-mode resonance under slot mode excitation, and then the inherent dielectric loss and conductor loss of the metasurface during resonance can be utilized to achieve reflection-free notch absorption of electromagnetic waves in the target frequency band.

[0041] Furthermore, in one embodiment, the gradient flaring slot line 4 includes a gradient slot line 4-1 having an exponential distribution characteristic, and a circular open slot line 4-2 along the central axis of the gradient flaring slot line 4 and arranged at the end of the gradient slot line 4-1; the gradient slot line 4-1 is used to achieve impedance matching between the antenna input port and the free space, and the circular open slot line 4-2 is used to achieve unidirectional radiation of the Vivaldi antenna and improve the impedance matching performance within the ultra-wide band.

[0042] Here, the end of the gradual groove line 4 - 1 refers to the end in the direction in which the groove line width gradually becomes narrower.

[0043] Here preferably, in some embodiments, the gradient groove line 4 - 1 is located within the projection of the metasurface 2 , and the circular open groove line 4 - 2 is located outside the projection of the metasurface 2 .

[0044] Here, preferably, in some embodiments, the central axis of the gradually expanding groove line 4 coincides with the projection of the central axis of the super surface 2 .

[0045] Furthermore, in one embodiment, the differential feed line 1 is a structure symmetrical about the projection of the central axis of the tapered flared slot line 4, and is used to connect the two input ports Port1 and Port2 located on both sides of the projection of the central axis of the tapered flared slot line 4. At the same time, the projection of the differential feed line 1 passes through the portion where the tapered slot line 4-1 is connected to the circular open slot line 4-2 and is close to the circular open slot line 4-2; the microstrip line-slot line broadband conversion structure formed by the differential feed line 1 and the tapered flared slot line 4 can ensure that the traveling wave slot mode is effectively excited when the differential mode signal is input, thereby exciting the metasurface 2 to generate dual-mode resonance, thereby realizing ultra-wideband radiation. At the same time, thanks to the mode mismatch between the common mode signal and the slot mode, the conversion structure can achieve excellent common mode suppression performance.

[0046] Preferably, in some embodiments, the differential feed line 1 includes a first feed line, a second feed line, and a third feed line connected in sequence, and the three feed lines form a right-angled U-shaped structure. The projection of the second feed line passes through the portion where the gradient slot line 4-1 is connected to the circular open slot line 4-2 and is close to the circular open slot line 4-2, that is, the projection of the U-shaped structure surrounds the circular open slot line 4-2.

[0047] It should be noted that the differential feeder 1 is not limited to the above-mentioned U-shaped structure, and any structure that meets the above-mentioned corresponding constraints and realizes the corresponding functions is acceptable.

[0048] In one embodiment, in order to accurately test the gain of the ultra-wideband differential Vivaldi antenna and overcome the problem that a balun converter needs to be additionally designed for differential mode signal input in the traditional differential antenna gain test, the present invention provides a continuous gain test method for differential end-fire antennas, combined with Figure 5 , specifically including:

[0049] Two pairs of ultra-wideband differential Vivaldi antennas, considered identical after processing, were selected to serve as the transmitting and receiving antennas in the gain test system, respectively. The antenna orientations were calibrated in a microwave anechoic chamber to ensure that the polarization directions of the two antennas were identical and aligned in the direction of maximum radiation. A four-port network consisting of the two ultra-wideband differential Vivaldi antennas and the spatial propagation path was then constructed.

[0050] By terminating with a broadband matching load, the arbitrary two-port scattering parameters of the four-port network are obtained using a vector network analyzer.

[0051] Based on the two-port scattering parameters, the differential mode transmission coefficient of the current spatial four-port network is obtained through balanced four-port network theory conversion;

[0052] Based on the differential mode transmission coefficient, the continuous gain of the ultra-wideband differential Vivaldi antenna is calculated according to the Friis transmission formula.

[0053] Furthermore, in one embodiment, the calculation formula of the continuous gain of the ultra-wideband differential Vivaldi antenna is:

[0054]

[0055] Where G meas is the continuous gain of the ultra-wideband differential Vivaldi antenna, d is the distance between the receiving antenna and the transmitting antenna, P r is the input power of the transmitting antenna, P t is the receiving power of the receiving antenna, λ is the wavelength of the gain test frequency in free space, S dd21 is the differential mode transmission coefficient between two ultra-wideband differential Vivaldi antennas.

[0056] Here, according to the balanced four-port network theory, the differential mode transmission coefficient S dd21 The conversion relationship with the two-port scattering parameters is:

[0057]

[0058] S 21 、S 23 、S 41 and S 43 The arbitrary two-port scattering parameters of the spatial four-port network are obtained by using a vector network analyzer.

[0059] Here, the received power of the receiving antenna is P r Expressed as:

[0060]

[0061] Where G is the antenna gain.

[0062] Preferably, as a specific example, the present invention is further verified and explained in some embodiments.

[0063] In this embodiment, combined with Figure 1 , the metal layer 3 and the dielectric substrate layer 5 are rectangular structures, then the ultra-wideband differential Vivaldi antenna is a rectangular structure, and the overall structure size is set to: length l x1 =125mm, width l y1 =89.1mm. Meanwhile, the differential feeder 1 adopts the above-mentioned U-shaped structure, and its length and line width are set as follows: the length of the first feeder and the third feeder is l4 = 21.3mm, the length of the second feeder is l5 = 40mm, and the width of the differential feeder 1 is w = 1.65mm.

[0064] In this embodiment, combined with Figure 2The material of the dielectric substrate 5 is Rogers 4350B, which has a relative dielectric constant of 3.66 and a loss tangent of 0.0037. The thickness of the dielectric substrate is set to: H = 0.762 mm.

[0065] In this embodiment, combined with Figure 3 The split resonant ring units are arranged in a rectangular array, and the length, line width, gap spacing and period spacing are set as follows: the length of the outer line of the split resonant ring unit p3 = 3 mm, the length of the inner line of the split resonant ring unit p4 = 2.7 mm, the line width of the split resonant ring unit w2 = 0.15 mm, the spacing between the two inner lines of the split resonant ring unit, i.e. the gap spacing g1 = 0.15 mm, and the spacing d between adjacent split resonant ring units in the horizontal direction x1 =4.2mm, the spacing d between adjacent split resonant ring units in the vertical direction y1 =3.6mm.

[0066] In this embodiment, combined with Figure 4 , the exponential function equation of the expansion groove line 4-1 is (unit: mm):

[0067] y=0.26e 0.075x +0.35

[0068] The radius of the end circular open groove line 4-2 is set to: r2=8mm.

[0069] Figure 6 is the differential mode reflection coefficient S obtained by simulating the ultra-wideband differential Vivaldi antenna under differential mode signal excitation in the present invention. dd11 It can be seen that S dd11 The impedance matching performance of the Vivaldi antenna is basically maintained below -10dB in the ultra-wide frequency band of 2 to 9.2GHz, which verifies the ultra-wide radiation impedance matching performance of the Vivaldi antenna under differential mode excitation. At the same time, taking the 5.15 to 5.825GHz WLAN operating frequency band as the notch target frequency band, it can be seen that S dd11 Many ripples appear in the 5.15 to 6.4 GHz frequency band, which is caused by the splitting of the metasurface resonance frequency due to electromagnetic mutual coupling between the split resonant ring units. The simulated notch frequency band bandwidth of 5.15-6.4 GHz can cover the WLAN operating frequency band.

[0070] Figure 7 (a) and Figure 7 Figure (b) shows the E-plane and H-plane radiation patterns of the ultra-wideband differential Vivaldi antenna of the present invention obtained by simulation and testing at a typical frequency of 7.5 GHz. It can be seen that the Vivaldi antenna has excellent end-fire performance.

[0071] Figure 8The gain diagram of the ultra-wideband differential Vivaldi antenna in the present invention is obtained by simulation and testing. Compared with the simulation results, the gain notch band obtained by the test is slightly shifted to high frequency, which may be caused by the instability of the relative dielectric constant of the dielectric substrate and the processing error. Figure 6 The differential mode reflection coefficient S dd11 It basically remains below -10dB in the ultra-wide frequency band of 2 to 9.2GHz, and Figure 8 The gain obtained in the test produced a notch response with a depth of more than 15dB in the 5.6 to 7.2GHz frequency band, proving the effectiveness of the ultra-wideband differential Vivaldi antenna design with reflection-free notch characteristics proposed in this invention; in addition, the gains obtained in simulation and testing showed good consistency, which also verified the effectiveness of the continuous gain test method for broadband differential end-fire antennas proposed in this invention.

[0072] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. An ultra-wideband differential Vivaldi antenna with non-reflection notch characteristics, characterized in that: The antenna comprises a metal stratum (3) and a dielectric substrate layer (5) arranged in sequence from bottom to top, and also comprises a differential feeder (1) and a metasurface (2) arranged on the dielectric substrate layer (5); the metasurface (2) can generate dual-mode resonance under slot mode excitation, and then utilize the inherent dielectric loss and conductor loss of the metasurface during resonance to achieve non-reflection notch absorption of electromagnetic waves in the target frequency band; a gradually expanding slot line (4) is etched on the metal stratum (3) to achieve ultra-wideband end-fire; the differential feeder (1) is used to be integrated with an external differential circuit, and at the same time, forms a microstrip line-slot line broadband conversion structure with the gradually expanding slot line (4) to achieve excitation ultra-wideband end-fire and common-mode suppression.

2. The ultra-wideband differential Vivaldi antenna with non-reflection notch characteristics according to claim 1, characterized in that: The metasurface (2) comprises a plurality of split resonant ring units (2-1) arranged in an array, and adjacent split resonant ring units (2-1) can form an electromagnetic coupling link.

3. The ultra-wideband differential Vivaldi antenna with non-reflection notch characteristics according to claim 2, characterized in that: The plurality of open resonant ring units (2-1) are arranged in a rectangular array.

4. The ultra-wideband differential Vivaldi antenna with non-reflection notch characteristics according to claim 3, characterized in that: Along the same horizontal direction of the rectangular array, the opening directions of the split resonant ring units (2-1) are the same; along the vertical direction of the rectangular array, adjacent split resonant ring units (2-1) have a central rotationally symmetrical structural feature.

5. The ultra-wideband differential Vivaldi antenna with non-reflection notch characteristics according to claim 1, characterized in that: The gradient flaring slot line (4) comprises a gradient slot line (4-1) having an exponential distribution characteristic, and a circular open slot line (4-2) arranged along the central axis direction of the gradient flaring slot line (4) and at the end of the gradient slot line (4-1); the gradient slot line (4-1) is used to achieve impedance matching between an antenna input port and free space, and the circular open slot line (4-2) is used to achieve unidirectional radiation of a Vivaldi antenna and improve impedance matching performance within an ultra-wideband.

6. The ultra-wideband differential Vivaldi antenna with non-reflection notch characteristics according to claim 5, characterized in that: The gradient groove line (4-1) is located within the projection of the super surface (2), and the circular open groove line (4-2) is located outside the projection of the super surface (2).

7. The ultra-wideband differential Vivaldi antenna with non-reflection notch characteristics according to claim 5, characterized in that: The central axis of the gradually expanding groove line (4) coincides with the projection of the central axis of the super surface (2).

8. The ultra-wideband differential Vivaldi antenna with non-reflection notch characteristics according to claim 5, characterized in that: The differential feed line (1) is a structure symmetrical about the projection of the central axis of the gradually expanding slot line (4), and is used to connect two input ports located on both sides of the projection of the central axis of the gradually expanding slot line (4). At the same time, the projection of the differential feed line (1) passes through the portion where the gradually expanding slot line (4-1) is connected to the circular open slot line (4-2) and is close to the circular open slot line (4-2). The microstrip line-slot line broadband conversion structure formed by the differential feed line (1) and the gradually expanding slot line (4) can ensure that a traveling wave slot mode is effectively excited when a differential mode signal is input, thereby exciting the metasurface (2) to generate dual-mode resonance, realizing ultra-wideband radiation, and simultaneously achieving excellent common-mode suppression.

9. The continuous gain test method for the ultra-wideband differential Vivaldi antenna according to any one of claims 1 to 8, characterized in that: The test method includes: Two identical ultra-wideband differential Vivaldi antennas were selected as the transmitting and receiving antennas, respectively. During the gain test, the polarization directions of the two antennas were ensured to be identical and aligned in the direction of maximum radiation. A four-port network consisting of the two ultra-wideband differential Vivaldi antennas and the spatial propagation path was then constructed. By terminating with a broadband matching load, the arbitrary two-port scattering parameters of the four-port network are obtained using a vector network analyzer. Based on the two-port scattering parameters, the differential mode transmission coefficient of the current spatial four-port network is obtained through balanced four-port network theory conversion; Based on the differential mode transmission coefficient, the continuous gain of the ultra-wideband differential Vivaldi antenna is calculated according to the Friis transmission formula.

10. The continuous gain testing method according to claim 9, wherein: The calculation formula of the continuous gain of the ultra-wideband differential Vivaldi antenna is: Where G meas is the continuous gain of the ultra-wideband differential Vivaldi antenna, d is the distance between the receiving antenna and the transmitting antenna, P r is the input power of the transmitting antenna, P t is the receiving power of the receiving antenna, λ is the wavelength of the gain test frequency in free space, S dd21 is the differential mode transmission coefficient between two ultra-wideband differential Vivaldi antennas.

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