An edge-fed tightly coupled wideband antipodal vivaldi antenna array

Abstract

The application provides an edge-loaded tightly-coupled broadband antipodal Vivaldi antenna array, and relates to the technical field of antennas; the antenna array comprises one or more antenna units; the antenna unit comprises a dielectric plate, a first radiation arm and a second radiation arm; the first radiation arm and the second radiation arm are arranged on the dielectric plate; the antenna unit further comprises a metal plate; the metal plate partially overlaps the first radiation arm and / or the second radiation arm and is arranged on the outer edge side of the first radiation arm and / or the second radiation arm; wherein the width of the metal plate is equal to half of the difference between the outer exponential curve opening width and the inner exponential curve opening width of the antenna unit. The application solves the problem that the existing antenna array cannot be miniaturized while maintaining high performance.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and more particularly to an edge-loaded, tightly coupled broadband antipodal Vivaldi antenna array. Background Technology

[0002] As the front end of a phased array radar, the performance of the phased array antenna directly affects the radar's capabilities. Wideband antennas are widely used in phased array antennas because they can receive and transmit narrow pulse signals, thereby improving recognition accuracy and signal-to-noise ratio. However, with the continuous development of antenna communication technology, the performance requirements for antennas are becoming more stringent; maintaining good wide-angle scanning capability, especially across a wide frequency band, remains a challenge for wideband phased array antennas.

[0003] Currently, antipodal Vivaldi antennas are mainly used to significantly improve the operating bandwidth of antennas. Antipodal Vivaldi antennas are proposed based on traditional single-sided Vivaldi antennas. By printing the two radiating arms of the antenna on the top and bottom sides of a dielectric substrate respectively, and using a graded balun feed, the bandwidth limitation caused by the traditional Vivaldi feed structure can be overcome. As a basic unit of phased array antennas, it can significantly improve the operating bandwidth of the antenna, and the antipodal Vivaldi antenna has a low input impedance, making it easy to match with the feed line. For example, some researchers have improved the impedance matching in the low-frequency band, enabling the antenna element to operate in the 1.48–7.5 GHz (5.07:1) frequency band with a size of 0.08λ. l / 0.45λ h Researchers have used metal pillars to short-circuit the radiating arms of antennas to suppress higher-order modes, enabling the antenna element to operate in the 6–18 GHz (3:1) frequency band with a size of 0.19λ. l / 0.57λ h Other researchers have improved the wide bandwidth scanning capability of the antenna by etching "pendulum-shaped" defect structures on the antenna arms, enabling the antenna element to operate in the 6–18 GHz (3:1) frequency band with a size of 0.17λ. l / 0.51λ h ; where λ l and λ h These represent the lowest and highest frequencies corresponding to the operating frequency band, respectively.

[0004] However, as antenna arrays become increasingly miniaturized, there is a growing demand to arrange as many antenna elements as possible within a limited physical space to support high integration and multifunctionality—that is, to reduce the size of the antenna elements and the antenna array while maintaining superior performance. In this case, the spacing between antenna elements is typically set to be small. The interaction between antenna elements can lead to coupling, especially when the elements are closely spaced and the spacing between them is less than half a wavelength, making the coupling effect particularly significant. Summary of the Invention

[0005] Therefore, it is necessary to provide an edge-loaded, tightly coupled broadband antipodal Vivaldi antenna array to address the aforementioned technical problems, thus solving the problem that existing antenna arrays cannot achieve miniaturization while maintaining high performance.

[0006] This invention proposes an edge-loaded, tightly coupled broadband antipodal Vivaldi antenna array, comprising one or more antenna elements; each antenna element includes a dielectric substrate, a first radiating arm, and a second radiating arm; the first radiating arm and the second radiating arm are disposed on the dielectric substrate; characterized in that the antenna element further includes a metal plate;

[0007] The metal plate partially overlaps with the first radiating arm and / or the second radiating arm, and is disposed on the outer edge side of the first radiating arm and / or the second radiating arm; wherein, the width of the metal plate is equal to half the difference between the width of the outer exponential curve opening and the width of the inner exponential curve opening of the antenna element.

[0008] Furthermore, the metal plate is provided with multiple metal through holes for loading short-circuit pins.

[0009] Furthermore, the metal vias can be configured in two ways: with equal spacing or with unequal spacing.

[0010] Furthermore, the antenna element operates at a frequency of 0.7–20 GHz and has a size of 0.03λ. l / 0.9λ h ; where λ l and λ h These represent the lowest and highest frequencies corresponding to the operating frequency band, respectively.

[0011] Furthermore, when multiple antenna elements are extended and arrayed along the E-plane, adjacent antenna elements are connected by the metal plate or short-circuit pins.

[0012] Furthermore, the antenna array also includes auxiliary radiating arms, which are connected to the first and last antenna elements of the E-plane via the metal plate or short-circuit pins, to suppress edge truncation effects.

[0013] Furthermore, the height of the auxiliary radiating arm is determined based on the heights of the first and second radiating arms; the width of the auxiliary radiating arm is adjusted based on the active standing wave ratio (VSWR) of the first and last antenna elements of the E-plane.

[0014] Furthermore, a short-circuit strip connected to ground is provided on the end antenna unit of the E-plane.

[0015] Furthermore, the width of the short-circuit strip is less than or equal to the width of the metal plate.

[0016] Furthermore, when multiple antenna elements are extended and arrayed along the H-plane, the spacing between the antenna elements in the H-plane is equal to the spacing between the antenna elements in the E-plane.

[0017] In summary, this invention provides an edge-loaded, tightly coupled broadband antipodal Vivaldi antenna array. Compared with existing technologies, the technical solution conceived in this invention can achieve the following beneficial effects:

[0018] (1) The present invention provides a metal plate that overlaps with the outer edge of the radiating arm. The overlapping part introduces a capacitor, which cancels out part of the inductance to ground, so that the antenna unit can start working from 1.96 GHz, expands the low frequency bandwidth, and has a wide bandwidth angle scanning capability without increasing the physical size of the antenna array. This achieves the miniaturization design of the antenna array while improving the overall performance of the antenna array.

[0019] (2) This invention uses metal vias to load short-circuit pins. The introduction of short-circuit pins not only eliminates some resonances but also effectively reduces the operating frequency of the antenna element, lowering the lower operating frequency to 0.7 GHz and extending the operating bandwidth to 0.7-20 GHz (28.6:1), with a corresponding size of 0.03λ. l / 0.9λ h It expands the operating bandwidth and improves antenna performance.

[0020] (3) From the perspective of tight coupling, the present invention enhances the coupling between antenna elements by edge overlap and short-circuit pins, eliminates resonance, expands the working bandwidth without increasing the physical size of the array, not only improves the overall performance of the array, but also realizes the miniaturization design of the antenna array.

[0021] (4) The present invention suppresses the edge cutoff effect by adding an auxiliary radiating arm and improves the performance of its low-frequency end by adding a short-circuit strip connected to ground on one side of the auxiliary radiating arm, thereby further improving the working bandwidth of the antenna array and extending the working frequency band of the antenna array to 0.8-12GHz (15:1), thus improving the wide bandwidth angle scanning capability. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the reflection coefficients of the antipodal Vivaldi antenna element and the traditional Vivaldi antenna element during their evolution, as provided by the present invention.

[0024] Figure 2 This is a schematic diagram of the structure of the antipodal Vivaldi antenna element provided by the present invention;

[0025] Figure 3 This is a schematic diagram of the gain and radiation efficiency of a Vivaldi antenna element provided by the present invention;

[0026] Figure 4 This is a schematic diagram of a one-dimensional E-plane plantar Vivaldi antenna array with added auxiliary radiating arms and short-circuit strips provided by the present invention;

[0027] Figure 5 This is a schematic diagram of the active standing wave ratio of antenna elements 1, 3, 5, and 8 in a one-dimensional E-plane pisiform Vivaldi antenna array with added auxiliary radiating arms and short-circuit strips, provided by the present invention.

[0028] Figure 6 This is a schematic diagram of the active standing wave ratio of a one-dimensional E-plane to the plantar Vivaldi antenna array with added auxiliary radiating arms and short-circuit strips provided by the present invention;

[0029] Figure 7 This is a schematic diagram of a one-dimensional H-plane plantar Vivaldi antenna array provided by the present invention;

[0030] Figure 8 This is a schematic diagram of the active standing wave ratio of a one-dimensional H-plane plantar Vivaldi antenna array provided by the present invention;

[0031] Figure 9 This invention provides a schematic diagram of an 8×8 antipodal Vivaldi antenna array and the corresponding antenna element numbers;

[0032] Figure 10 This is a schematic diagram of the active standing wave ratio (VSWR) of antenna elements numbered 1-8, 9-16, 17-24, and 25-32 in an 8×8 antipodal Vivaldi antenna array provided by the present invention.

[0033] Figure 11This is a schematic diagram of the normal gain and aperture efficiency of an 8×8 antipodal Vivaldi antenna array provided by the present invention;

[0034] Figure 12 This is a schematic diagram of the E-plane scanning normalized radiation direction of an 8×8 antipodal Vivaldi antenna array provided by the present invention;

[0035] Figure 13 This is a schematic diagram of the H-plane scanning normalized radiation direction of an 8×8 antipodal Vivaldi antenna array provided by the present invention;

[0036] 100 - dielectric substrate; 200 - first radiating arm; 300 - second radiating arm; 400 - metal plate; 500 - metal via. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0038] It should be noted that in the description of the embodiments of the present invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an antenna array comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an antenna array. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the antenna array that includes said element.

[0039] Traditional antipodal Vivaldi antennas are relatively large, which is particularly unfavorable for achieving wide-angle scanning at high frequencies. Therefore, it is necessary to further miniaturize the antenna array while ensuring the wide bandwidth characteristics of the antenna.

[0040] A common conventional anti-torsional Vivaldi antenna element structure includes a dielectric substrate 100, a first radiating arm 200, and a second radiating arm 300; the first radiating arm 200 and the second radiating arm 300 are disposed on the dielectric substrate 100. A periodic simulation of the conventional anti-torsional Vivaldi antenna element is performed in CST, with the original dimensions remaining unchanged. The four sides of the antenna element are set as periodic boundaries, and a waveport is used for feeding. The simulated reflection coefficient S is obtained. 11 like Figure 1As shown, its operating frequency band starts from 5.74 GHz. Compared with a single antenna, the frequency at the low end is actually higher. This is mainly because the overall size of the traditional antipodal Vivaldi antenna element is large, which makes it impossible to achieve effective coupling utilization, thus limiting the operating bandwidth.

[0041] Although adjusting the dimensions of the dielectric substrate 100, the first radiating arm 200, and the second radiating arm 300 can reduce the antenna element period and lower the minimum operating frequency to some extent, there are still some fluctuations in the reflection coefficient at the high-frequency end.

[0042] As a specific embodiment, by adjusting the dimensions of the dielectric substrate 100, the first radiating arm 200, and the second radiating arm 300, the following can be obtained: Figure 2 Antenna element (a) shows the following: inner exponential curve length l1 = 55 mm, outer exponential curve length l2 = 5 mm, outer edge of the feed balun is an elliptic curve with minor axis radius l3 = 6 mm, initial width of the radiating arm w0 = 1.9 mm, inner exponential curve opening width w1 = 12 mm, outer exponential curve opening width w2 = 15 mm. The antenna element period p is reduced to p = 15 mm, and the minimum operating frequency is lowered to 3.38 GHz, but the high-frequency reflection coefficient S... 11 There are still fluctuations around -10dB.

[0043] Since the antipodal Vivaldi antenna is a double-sided structure, this invention adopts the design method of a tightly coupled dipole antenna to provide an edge-loaded tightly coupled broadband antipodal Vivaldi antenna array, including one or more antenna elements; based on the traditional antipodal Vivaldi antenna element, the antenna element of this invention also includes a metal plate 400.

[0044] The metal plate 400 partially overlaps with the first radiating arm 200 and / or the second radiating arm 300, and is disposed on the outer edge side of the first radiating arm 200 and / or the second radiating arm 300. The width of the metal plate 400 is equal to half the difference between the width of the outer exponential curve opening and the width of the inner exponential curve opening of the antenna element.

[0045] That is: s1 = (w2 - w1) / 2; s1 represents the width of the metal plate 400; w2 represents the width of the outer exponential curve opening of the antenna element; w1 represents the width of the inner exponential curve opening of the antenna element.

[0046] It should be noted that the capacitor introduced by the overlapping metal plate 400 cancels out part of the inductance to ground, thereby expanding the low-frequency bandwidth. In addition, when setting up the antenna array, the upper and lower parts of the two arms of adjacent antenna elements can be overlapped by the metal plate 400, reducing the antenna element period.

[0047] As a specific example, such as Figure 2 As shown in (b), the antenna element period is p = 13.5 mm. Due to the capacitance introduced by the overlapping metal plate 400, the antenna element can start operating from 1.96 GHz.

[0048] Because the antenna element with metal plate 400 has a reflection coefficient S 11 There are still some fluctuations, and some resonances have also appeared within the array.

[0049] It should be noted that partial resonance mainly occurs inside the dielectric substrate 100, which will cause a deterioration in the H-plane scanning characteristics. The resonant frequency f... res The estimation formula is:

[0050]

[0051] Where c represents the speed of light; ε r denoted by relative permittivity; m and n represent the number of half-waves distributed along the width and length of the antenna element, respectively, with m = n = 1 for the main resonant mode; p represents the antenna element period; l1 represents the length of the inner exponential curve of the antenna element; l3 represents the radius of the minor axis of the elliptic curve at the outer edge of the feed balun of the antenna element.

[0052] In order to eliminate some resonance or make it resonate outside the operating frequency band, the present invention also provides a plurality of metal vias 500 on the metal plate 400 for loading short-circuit pins.

[0053] When assembling the array, short-circuit pins connect the metal plates 400 on both sides of the dielectric substrate 100. The introduction of short-circuit pins not only eliminates resonance within the array but also further enhances coupling, effectively reducing the operating frequency of the cells.

[0054] Furthermore, the metal vias 500 can be configured in two ways: with equal spacing or with unequal spacing. Equal spacing is preferred.

[0055] As a specific embodiment, short-circuit pins spaced 4mm apart on the metal plate 400 are provided to obtain the following result: Figure 2 (cd) shows the antipodal Vivaldi antenna element. The introduction of the short-circuit pin not only eliminates resonance within the array but also further enhances coupling, effectively reducing the operating frequency of the antenna element and extending the operating bandwidth to 0.7–20 GHz (28.6:1), with a corresponding size of 0.03λ. l / 0.9λ h ; where λ l and λ h These represent the lowest and highest frequencies corresponding to the operating frequency band, respectively.

[0056] Unlike a typical single-sided Vivaldi antenna, the slots of a pinpophyseal Vivaldi antenna start from zero, therefore, theoretically its operating frequency can be infinite. However, in specific application environments, other factors need to be considered.

[0057] As an embodiment of the present invention, such as Figure 3 As shown, the gain and radiation efficiency of the antenna element with a 500-degree metal via are presented. It can be seen that the antenna element can effectively radiate, with a radiation efficiency exceeding 58.9% within the band and remaining above 80% above 1.2 GHz. This demonstrates that the antenna element expands the operating bandwidth and achieves miniaturization, making it suitable for further array research.

[0058] Since the antenna element design is based on an ideal scenario simulating an infinitely large array, the array environment for each element is considered identical. However, infinitely large arrays do not exist in reality, and the array environments for elements in a finite array differ from those in an infinitely large array, leading to performance differences between elements. Therefore, further detailed analysis is required.

[0059] Because the antenna elements of an E-plane array are directly connected, the coupling is strong. However, for the edge elements, the coupling environment is different from that of the periodic boundary, resulting in an edge truncation effect.

[0060] As an embodiment of the present invention, when multiple antenna elements are extended and arrayed along the E-plane, adjacent antenna elements are connected by a metal plate 400 or a short-circuit pin.

[0061] It should be noted that the antenna element is divided into the E-plane and the H-plane, such as... Figure 2 As shown in (d), the plane along the x-axis is the E-plane, and the plane along the y-axis is the H-plane.

[0062] As a specific embodiment, the antenna elements are extended and arrayed along the E-plane. Figure 4 As shown, eight antenna elements are arranged sequentially along the x-axis to form a one-dimensional E-plane finite array, with the antenna elements labeled 1 to 8. During the simulation, the four planes along the x-axis and z-axis are set as open boundaries in free space, while the two planes along the y-axis remain as periodic boundaries.

[0063] This section considers the performance of the array during spatial scanning. The condition for preventing grid lobes in the array design is: Where d represents the spacing between antenna elements in the antenna array, λ represents the wavelength at which the grating lobe appears, and θ represents the scanning angle. When performing a large-angle scan, such as θ = 60°, with an antenna element spacing of d = p = 13.5 mm, the frequency corresponding to the wavelength at which the grating lobe appears is approximately 12 GHz. Therefore, the upper limit frequency for the array operation is set to 12 GHz.

[0064] When performing large-angle scanning, such as θ = 60° and the element spacing d = p = 13.5 mm, the frequency corresponding to the wavelength of the grating lobe is calculated to be approximately 12 GHz. Therefore, the upper limit frequency for array operation is set to 12 GHz.

[0065] Antenna elements 2 through 7 all exhibit good active VSWRs, less than 2 within the 0.8-12 GHz range. However, due to the edge truncation effect, antenna elements 1 and 8 at the beginning and end are only connected to other antenna elements on one side, resulting in poor active VSWRs for antenna elements 1 and 8, especially at low frequencies. Therefore, they cannot maintain an array environment similar to that of antenna elements 2 through 7. Thus, a reasonable method is needed to suppress the edge truncation effect.

[0066] As an embodiment of the present invention, the edge truncation effect can be effectively suppressed by continuing to add antenna elements or vertically setting metal baffles.

[0067] However, these methods will increase the size of the antenna array or increase the complexity of the antenna array structure.

[0068] Therefore, the antenna array of the present invention also includes an auxiliary radiating arm, which is connected to the first and last antenna elements of the E-plane via a metal plate 400 or a short-circuit pin, in order to suppress the edge truncation effect.

[0069] As an example, the height of the auxiliary radiating arm is determined based on the height of the first radiating arm 200 and the second radiating arm 300; the width of the auxiliary radiating arm is adjusted based on the active VSWR of the first and last antenna elements on the E plane.

[0070] As a specific example, such as Figure 4 As shown, auxiliary radiating arms are added to the sides of the short-circuit pins of the first antenna element 1 and the last antenna element 8. More specifically, the width s3 of the auxiliary radiating arm is s3 = 18 mm, adjusted according to the active VSWR of the first antenna element 1 and the last antenna element 8. The height of the auxiliary radiating arm is equal to the height of the first radiating arm 200 and the second radiating arm 300 of the antenna element.

[0071] The width of the auxiliary radiating arm can be adjusted based on the active VSWR of the first and last antenna elements of the E-plane. Furthermore, the width of the auxiliary radiating arm can be adjusted based on the active VSWR of all antenna elements of the E-plane, or based on the active VSWR of the first and last antenna elements and the antenna elements at the middle position of the array randomly selected.

[0072] For example, obtain the active VSWR curves of antenna elements 1, 3, 5, and 8, such as... Figure 5 As shown, from Figure 5As can be seen from (b) and (c), as the width of the auxiliary radiating arm increases, the active VSWR of the two relatively central antenna elements in the one-dimensional E-plane antenna array, namely antenna element 3 and antenna element 5, remains almost unchanged. The only change is a slight improvement in the matching of antenna element 5 at around 2 GHz. Increasing the width of the radiating arm primarily affects the two edge antenna elements. Figure 5 As shown in (a), when s3 increases from 0 to 6 mm, i.e., by increasing the radiating arm, the active VSWR of antenna element 1 is significantly improved, and by further increasing the width, the operating frequency of antenna element 1 is reduced to 0.8 GHz. For antenna element 8, as the auxiliary radiating arm widens, the active VSWR is significantly improved. When s3 increases to 18 mm, the active VSWR of antenna element 8 is below 2 after 1.68 GHz. However, when s3 increases further, the active VSWR at the low-frequency end deteriorates. Therefore, after comprehensive consideration, the width s3 of the auxiliary radiating arm is determined to be 18 mm.

[0073] It should be noted that the operating bandwidth of the antenna array with short-circuit pins is mainly limited by antenna element 8, whose lower operating frequency is 1.68 GHz, while the lower limits of other antenna elements are around 0.8 GHz. Therefore, the operating bandwidth of the antenna array can be further improved by making structural improvements to antenna element 8.

[0074] As an example, to suppress leakage from side radiation, a short-circuit strip connected to ground is provided on the end antenna element of the E-plane. In the one-dimensional E-plane antenna array, only antenna element 8 is equipped with the short-circuit strip; the other antenna elements remain as antenna elements. More specifically, the width of the short-circuit strip is less than or equal to the width of the metal plate 400.

[0075] For example, such as Figure 4 As shown, a short-circuit strip connected to ground is loaded at the end of one arm of antenna element 8 to improve its low-frequency performance; the width of the short-circuit strip s4 is s4 = 0.8 mm; its one-dimensional E-plane active standing wave ratio of the Vivaldi antenna array is as follows: Figure 6 As shown, it can be seen that the active VSWR of antenna element 8 has been significantly improved. Its lower limit frequency is basically the same as that of other array elements, while the other antenna elements have not changed. The operating frequency band of the one-dimensional E-plane antenna array is 0.8-12GHz (15:1).

[0076] As an example, when multiple antenna elements are extended and arrayed along the H-plane, the spacing between the antenna elements in the H-plane is equal to the spacing between the antenna elements in the E-plane.

[0077] As a specific embodiment, the antenna element is extended one-dimensionally along the y-axis, such as... Figure 7As shown, there are eight antenna elements distributed in total, numbered from 1 to 8. The spacing between the antenna elements is the same as the spacing between the antenna elements of the E-plane array, which is p = 13.5 mm.

[0078] In the simulation, the four surfaces along the y and z axes are set as open free-space boundaries, and the two surfaces along the x-axis are set as periodic boundaries. The active standing wave ratio of a one-dimensional H-plane antenna array is as follows: Figure 8 As shown, the H-plane antenna array does not exhibit a significant edge truncation effect. Each antenna element in the array maintains the superior characteristics of a single antenna element, and the consistency is well maintained. The operating frequency band of the antenna array is 0.8-12 GHz. Furthermore, it can be observed that although the overall structure is not symmetrical, the active VSWR of two antenna elements opposite each other along the y-axis is essentially the same.

[0079] As a specific embodiment, a finite antenna array is obtained by extending a one-dimensional E-plane plantar Vivaldi antenna array along the y-axis. For example... Figure 9 The diagram shown is a schematic diagram of an 8×8 antipodal Vivaldi antenna array and the corresponding antenna element numbers provided by the present invention, and its performance is analyzed.

[0080] Impedance matching performance is analyzed. Since the antenna array is not an axisymmetric structure, while the performance of the H-plane antenna array is relatively symmetrical, therefore, for half of the elements in the antenna array, i.e., ... Figure 9 The active VSWR of antenna elements 1-32 shown was simulated. Figure 10 As shown, Figure 10 (ad) shows the active VSWR results for antenna elements 1–8, 9–16, 17–24, and 25–32, respectively. It can be seen that the performance of each antenna element in the antenna array is good; within the operating frequency band of 0.82–12 GHz (14.6:1), the active VSWR is generally less than 2, corresponding to an antenna element size of 0.04λ. l / 0.54λ h Although the active VSWR of antenna element 8 deteriorated to some extent at the low frequency end, mainly due to the E-plane edge truncation effect that could not be completely suppressed, the overall active VSWR was still below 2.2, and it still had good performance.

[0081] The far-field radiation performance was analyzed. For example... Figure 11 As shown, the normal gain and aperture efficiency of an 8×8 Vivaldi antenna array are presented. Figure 11 (a) also provides the theoretical value curves, which show that the normal gain of the antenna array within the band is very close to the theoretical value, thus its aperture efficiency reaches over 80% within the band. Furthermore, the normal gain curve decreases after 13 GHz, verifying the upper limit of the antenna array's operating frequency.

[0082] Figure 12 and Figure 13 The radiation patterns of the antenna array during E-plane and H-plane scanning are presented respectively. The antenna array exhibits better scanning performance at low frequencies.

[0083] At 1 GHz, the gain changes during E-plane and H-plane scanning are within 1.1 dB and 0.2 dB, respectively. When the antenna array scans in the -x-axis space, the half-power beamwidth of the E-plane pattern increases with the increase of the scan angle; when scanning in the +x-axis space, the half-power beamwidth first decreases and then increases, but both are greater than 60°, with the maximum value of 73.6° appearing when scanning to -60°. The variation trend of the half-power beamwidth of the H-plane pattern in the +y and -y-axis spaces is the same as that of the E-plane in the -x and +x spaces, respectively. The half-power beamwidth of the E-plane is larger than that of the H-plane, mainly because the E-plane size of the array is larger than that of the H-plane. The sidelobe electrical values ​​of both the E-plane and H-plane scanning patterns increase with the increase of the scan angle, but both remain below -10 dB. At 4 GHz, the gain changes during E-plane and H-plane scanning are both within 2.0 dB. The half-power beamwidth of the H-plane pattern increases with increasing scan angle, while that of the E-plane pattern increases first and then decreases. The sidelobe voltages of both the E-plane and H-plane scanning patterns increase with increasing scan angle. Meanwhile, at 8 GHz, the gain changes during E-plane and H-plane scanning are within 2.4 dB and 2.8 dB, respectively. The half-power beamwidth of the H-plane pattern increases with increasing scan angle, while the E-plane pattern shows an overall increasing trend, but experiences a significant decrease to only 18.9° when scanning to -45°. The sidelobe voltages of the H-plane scanning pattern increase with increasing scan angle, while the sidelobe levels of the E-plane remain relatively consistent during scanning. At 12 GHz, the gain changes during E-plane and H-plane scanning are within 2.5 dB and 2.2 dB, respectively. The half-power beamwidth of the H-plane pattern increases with increasing scan angle, while the E-plane beamwidth initially increases and then decreases during scanning along the +x-axis, and similarly decreases to only 15.8° at -45° during scanning along the -x-axis. Similarly, the sidelobe electrical averages of both the E-plane and H-plane scanning patterns increase with increasing scan angle, resulting in some pattern deterioration. Overall, the antenna array maintains good radiation direction during scanning, and the gain change remains within 3 dB, thus demonstrating good scanning capability.

[0084] In summary, by constructing an edge-loaded 8×8 finite antipodal Vivaldi antenna array for verification, the active VSWR of the antenna array is basically less than 2 in the operating frequency band of 0.82-12GHz (14.6:1), and both the E-plane and H-plane can achieve beam scanning of ±60°. The constructed antenna array has wide bandwidth angle scanning capability.

[0085] It should be noted that, for the sake of simplicity, the foregoing embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, and some steps may be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0086] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments. It should be understood that the disclosed methods or systems can be implemented in other ways in the several embodiments provided in this application. For example, the embodiments described above are merely illustrative; for example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0087] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0088] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0089] The foregoing description is merely an exemplary embodiment of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Those skilled in the art will readily conceive of embodiments of this disclosure upon considering the specification and practicing the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described herein. The specification and embodiments are to be considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

[0090] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0091] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An edge-loaded, tightly coupled broadband antipodal Vivaldi antenna array, comprising one or more antenna elements; each antenna element comprising a dielectric substrate, a first radiating arm, and a second radiating arm; the first radiating arm and the second radiating arm are disposed on the dielectric substrate; characterized in that, The antenna unit also includes a metal plate; The metal plate partially overlaps with the first radiating arm and / or the second radiating arm, and is disposed on the outer edge side of the first radiating arm and / or the second radiating arm; wherein, the width of the metal plate is equal to half the difference between the opening width of the outer exponential curve and the opening width of the inner exponential curve of the antenna element; when setting up the antenna array, the upper and lower parts of the two arms of adjacent antenna elements are placed overlapping by the metal plate, and the metal plate is provided with multiple metal through holes for loading short-circuit pins; when multiple antenna elements are extended and arrayed along the E plane, adjacent antenna elements are connected by the metal plate or the short-circuit pins.

2. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 1, characterized in that, The metal vias can be configured in two ways: with equal spacing or with unequal spacing.

3. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 1, characterized in that, The antenna element operates at a frequency of 0.7~20GHz and has a size of [missing information]. ;in, and These represent the lowest and highest frequencies corresponding to the operating frequency band, respectively.

4. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 1, characterized in that, The antenna array also includes auxiliary radiating arms, which are connected to the first and last antenna elements of the E-plane via the metal plate or short-circuit pins to suppress edge truncation effects.

5. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 4, characterized in that, The height of the auxiliary radiating arm is determined based on the heights of the first and second radiating arms; the width of the auxiliary radiating arm is adjusted based on the active standing wave ratio (VSWR) of the first and last antenna elements of the E-plane.

6. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 4, characterized in that, A short-circuit strip connected to ground is provided on the end antenna unit of the E-plane.

7. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 6, characterized in that, The width of the short-circuit strip is less than or equal to the width of the metal plate.

8. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 1, characterized in that, When multiple antenna elements are extended and arrayed along the H-plane, the spacing between the antenna elements in the H-plane is equal to the spacing between the antenna elements in the E-plane.

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