Edge-loaded tight coupling broadband antipodal Vivaldi antenna array

Abstract

The invention provides an edge-loaded tight coupling 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 is partially overlapped with 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 value between the outer index curve opening width and the inner index curve opening width of the antenna unit. According to the invention, the problem that the existing antenna array cannot be miniaturized while maintaining high performance is solved.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to an edge-loaded tightly coupled broadband antipodal Vivaldi antenna array. Background Art

[0002] Phased array antennas are the front end of phased array radars, and their performance directly affects the performance of the radar. Wideband antennas are widely used in phased array antennas because they can receive and send narrow pulse signals to improve recognition accuracy and signal-to-noise ratio. However, with the continuous development of antenna communication technology, the performance requirements for antennas have become more stringent; in particular, maintaining good wide-angle scanning capabilities within a wider frequency band is a difficulty for broadband phased array antennas.

[0003] At present, the antipodal Vivaldi antenna is mainly used to greatly improve the working bandwidth of the antenna. The antipodal Vivaldi antenna is proposed on the basis of the traditional single-sided Vivaldi antenna. By printing the two radiating arms of the antenna on the upper and lower sides of the dielectric board respectively and using a gradient balun feeding, it can break through the bandwidth limitation caused by the traditional Vivaldi feeding structure; as the basic unit of the phased array antenna, it can greatly improve the working bandwidth of the antenna, and the antipodal Vivaldi antenna has a low input impedance, which is easy to match with the feed line. For example, some researchers have improved the impedance matching in the low frequency band so that the working frequency band of the antenna unit is 1.48~7.5GHz (5.07:1) and the size is 0.08λ. l / 0.45λ h ; Some researchers used metal columns to short-circuit the antenna radiation arm to suppress high-order modes, allowing the antenna unit to operate in the 6-18 GHz (3:1) frequency band with a size of 0.19λ l / 0.57λ h Other researchers have etched a pendulum-shaped defect structure on the antenna arm to improve its wide-bandwidth angular scanning capability, making the antenna unit work in the 6-18 GHz (3:1) frequency band with a size of 0.17λ. l / 0.51λ h ; Among them, λ l and λ h Respectively represent the lowest and highest frequencies corresponding to the working frequency band.

[0004] However, as antenna arrays gradually develop towards miniaturization, it is required to arrange as many antenna units as possible in a limited physical space to support high integration and multi-functions, that is, to reduce the size of antenna units and antenna arrays while maintaining superior performance. In this case, the spacing between antenna units is usually set to be small. The interaction between antenna units will cause coupling between antenna units, especially when the antenna units are closely arranged and the spacing between antenna units is less than half a wavelength, the coupling effect becomes particularly significant. Summary of the invention

[0005] Based on this, it is necessary to provide an edge-loaded tightly coupled broadband antipodal Vivaldi antenna array to address the above technical problems, which solves the problem that existing antenna arrays cannot be miniaturized while maintaining high performance.

[0006] The present invention provides an edge-loaded tightly coupled broadband antipodal Vivaldi antenna array, comprising one or more antenna units; the antenna unit comprises a dielectric plate, a first radiating arm and a second radiating arm; the first radiating arm and the second radiating arm are arranged on the dielectric plate; the antenna unit further comprises a metal plate;

[0007] The metal plate partially overlaps with 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 opening width of the outer exponential curve and the opening width of the inner exponential curve of the antenna unit.

[0008] Furthermore, the metal plate is provided with a plurality of metal vias for loading short-circuit pins.

[0009] Furthermore, the metal vias are arranged in equal intervals or unequal intervals.

[0010] Furthermore, the antenna unit has an operating frequency of 0.7 to 20 GHz and a size of 0.03λ. l / 0.9λ h ; Among them, λ l and λ h They respectively represent the lowest frequency and the highest frequency corresponding to the working frequency band.

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

[0012] Furthermore, the antenna array also includes an auxiliary radiation arm, which is connected to the first and last antenna units of the E-plane through the metal plate or the short-circuit pin, so as to suppress the edge truncation effect.

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

[0014] Furthermore, a short-circuit strip connected to the 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 units are extended and arrayed along the H plane, the spacing between the antenna units on the H plane is equal to the spacing between the antenna units on the E plane.

[0017] In general, the present invention provides an edge-loaded tightly coupled broadband antipodal Vivaldi antenna array. The technical solution conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0018] (1) The present invention provides a metal plate partially overlapping the radiation arm on the outer edge side of the radiation arm, thereby introducing a capacitor into the overlapping portion to offset a portion of the inductance to the ground, so that the antenna unit can start working from 1.96 GHz, thereby expanding the low-frequency bandwidth, and achieving wide-bandwidth angular scanning capability without increasing the physical size of the antenna array, thereby achieving a miniaturized design of the antenna array and improving the overall performance of the antenna array.

[0019] (2) The present invention sets a metal via to load the short-circuit pin. The introduction of the short-circuit pin not only eliminates part of the resonance, but also effectively reduces the operating frequency of the antenna unit, so that the lower limit operating frequency is reduced to 0.7 GHz, and the operating frequency band is extended to 0.7-20 GHz (28.6:1), and the corresponding size is 0.03λ l / 0.9λ h ; Expanded the working bandwidth and improved the antenna performance.

[0020] (3) From the perspective of tight coupling, the present invention enhances the coupling between antenna units through edge overlap and short-circuit pins, eliminates resonance, and expands the working bandwidth without increasing the physical size of the array, which 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 truncation effect by adding an auxiliary radiating arm, and improves the performance of the low-frequency end by adding an end short-circuit strip connected to the ground on one side of the auxiliary radiating arm, thereby further improving the working bandwidth of the antenna array, so that the working frequency band of the antenna array is expanded to 0.8-12GHz (15:1), thereby improving the wide bandwidth angle scanning capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of reflection coefficients during the evolution of the antipodal Vivaldi antenna unit provided by the present invention and the traditional Vivaldi antenna unit;

[0024] Figure 2 is a structural schematic diagram of the antipodal Vivaldi antenna unit provided by the present invention;

[0025] Figure 3 Schematic diagram of gain and radiation efficiency of an antipodal Vivaldi antenna unit provided by the present invention;

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

[0027] Figure 5 It is a schematic diagram of active standing wave ratio of antenna units 1, 3, 5, and 8 in a one-dimensional E-plane Vivaldi antenna array with auxiliary radiation arms and short-circuit strips provided by the present invention;

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

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

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

[0031] Fig. 9 It is a schematic diagram of an 8×8 antipodal Vivaldi antenna array provided by the present invention and the corresponding antenna unit numbering;

[0032] Fig.10 It is a schematic diagram of active standing wave ratio of antenna units numbered 1 to 8, 9 to 16, 17 to 24, and 25 to 32 in an 8×8 antipodal Vivaldi antenna array provided by the present invention;

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

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

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

[0036] 100 - dielectric plate; 200 - first radiation arm; 300 - second radiation arm; 400 - metal plate; 500 - metal via. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in combination with the drawings and embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0038] It should be noted that, in the description of the embodiments of the present invention, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that an antenna array including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such antenna array. In the absence of further restrictions, the elements defined by the sentence "include one..." do not exclude the existence of other identical elements in the antenna array including the elements.

[0039] The size of the traditional antipodal Vivaldi antenna is 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 broadband characteristics of the antenna.

[0040] A common traditional antipodal Vivaldi antenna unit structure includes a dielectric plate 100, a first radiating arm 200 and a second radiating arm 300; the first radiating arm 200 and the second radiating arm 300 are arranged on the dielectric plate 100. The traditional antipodal Vivaldi antenna unit is periodically simulated in CST, the original size remains unchanged, the four sides of the antenna unit are set as periodic boundaries, and the wave port is used for feeding. The reflection coefficient S 11 like Figure 1As shown, its operating frequency band starts from 5.74 GHz. Compared with a single antenna, the frequency at the low frequency end is actually higher. This is mainly because the overall size of the traditional antipodal Vivaldi antenna unit is large and effective coupling utilization cannot be achieved, so the operating bandwidth is limited.

[0041] Although the antenna unit period can be reduced to a certain extent and the minimum operating frequency can be lowered by adjusting the sizes of the dielectric plate 100, the first radiation arm 200 and the second radiation arm 300, there are still some fluctuations in the reflection coefficient at the high frequency end.

[0042] As a specific embodiment, the dimensions of the dielectric plate 100, the first radiation arm 200 and the second radiation arm 300 are adjusted to obtain the following: Figure 2 (a) shows the antenna unit: the length of the inner exponential curve is l1 = 55mm, the length of the outer exponential curve is l2 = 5mm, the outer edge of the feed balun is the short axis radius of the elliptical curve is l3 = 6mm, the starting width of the radiation arm is w0 = 1.9mm, the opening width of the inner exponential curve is w1 = 12mm, and the opening width of the outer exponential curve is w2 = 15mm. The antenna unit period p is reduced to p = 15mm, and the minimum operating frequency is reduced to 3.38GHz, but the reflection coefficient S at the high frequency end is 11 There is still fluctuation around -10dB.

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

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

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

[0046] It should be noted that since the overlapping metal plate 400 introduces capacitance, a part of the inductance to the ground is offset, thereby achieving the expansion of the low-frequency bandwidth; in addition, when setting up the antenna array, the upper and lower parts of the two arms of adjacent antenna units can be placed overlappingly through the metal plate 400, thereby reducing the antenna unit period.

[0047] As a specific example, Figure 2 As shown in (b), the antenna unit period is p = 13.5 mm. Since the overlapping metal plate 400 introduces capacitance, the antenna unit can start to work from 1.96 GHz.

[0048] Since the reflection coefficient S of the antenna unit of the metal plate 400 is set 11 There are still some fluctuations and some resonances within the array.

[0049] It should be noted that the partial resonance is mainly generated inside the dielectric plate 100, which will cause the deterioration of the H-plane scanning characteristics. res The estimation formula is:

[0050]

[0051] Where c is the speed of light; ε r Represents the relative dielectric constant; m and n represent the number of half-waves distributed in the width direction and length direction of the antenna unit respectively, and m=n=1 corresponding to the main resonance mode; p represents the period of the antenna unit; l1 represents the length of the inner exponential curve of the antenna unit; l3 represents that the outer edge of the feeding balun of the antenna unit is the minor axis radius of the elliptical curve.

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

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

[0054] Furthermore, the arrangement of the metal vias 500 includes: equidistant arrangement or unequal distance arrangement, preferably equidistant arrangement.

[0055] As a specific embodiment, short-circuit pins with a distance s2 = 4 mm are arranged on the metal plate 400 to obtain Figure 2 (cd) The antipodal Vivaldi antenna unit shown. The introduction of the short-circuit pin can not only eliminate the resonance within the array, but also further enhance the coupling, effectively reducing the operating frequency of the antenna unit, and expanding the operating frequency band to 0.7~20GHz (28.6:1), corresponding to a size of 0.03λ l / 0.9λ h ; Among them, λ l and λ h They respectively represent the lowest frequency and the highest frequency corresponding to the working frequency band.

[0056] Different from the common single-sided Vivaldi antenna, the slot of the antipodal Vivaldi antenna starts from 0, so theoretically its operating frequency can be infinite. However, in the specific application environment, other factors need to be considered.

[0057] As an embodiment of the present invention, Figure 3 As shown, the gain and radiation efficiency of the antenna unit with the metal via 500 are given. It can be seen that the antenna unit can effectively radiate, and the radiation efficiency is above 58.9% in the band and remains above 80% after 1.2GHz. It can be seen that the antenna unit expands the working bandwidth on the one hand, and achieves miniaturization on the other hand, and can be further used for array research.

[0058] Since the antenna unit is designed under ideal conditions and simulates an infinite array, the array environment of each array element is considered to be the same. However, in reality, an infinite array does not exist, and the array environment of a finite array is different from that of an infinite array, resulting in performance differences between array elements, so further specific analysis is needed.

[0059] Since the antenna units of the E-plane array are directly connected, the coupling is strong. However, for the edge array elements, their coupling environment is different from the periodic boundary, and there is an edge truncation effect.

[0060] As an embodiment of the present invention, when multiple antenna units are extended and arrayed along the E-plane, adjacent antenna units are connected via metal plates 400 or short-circuit pins.

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

[0062] The antenna units are extended and arrayed along the E plane, as a specific embodiment, as shown in FIG. Figure 4 As shown, eight antenna units are arranged in sequence along the x-axis to form a one-dimensional E-plane finite array, and the antenna units are marked as 1 to 8. During simulation, the four surfaces along the x-axis and the z-axis are set as free space open boundaries, and the two surfaces along the y-axis are still kept as periodic boundaries.

[0063] Here we consider the performance of the array when performing spatial scanning, because the condition for no grating lobe to appear in the array design is: Where d represents the antenna unit spacing in the antenna array, λ represents the wavelength at which grating lobes appear, and θ represents the scanning angle. When performing large-angle scanning, such as θ = 60°, the antenna unit spacing d = p = 13.5 mm, and the frequency corresponding to the wavelength at which grating lobes appear is approximately 12 GHz, so the upper limit frequency of the array operation is set to 12 GHz.

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

[0065] Antenna units 2 to 7 all have good active standing wave ratios, which are all less than 2 in the range of 0.8-12GHz. However, due to the influence of the edge truncation effect, antenna units 1 and 8 at the head and end are only connected to other antenna units on one side, resulting in poor active standing waves of antenna units 1 and 8, which is particularly serious at the low frequency end, so they cannot maintain a similar array environment with antenna units 2 to 7. Therefore, 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 units or vertically arranging metal baffles.

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

[0068] Therefore, the antenna array of the present invention further includes an auxiliary radiation arm, which is connected to the first and last antenna units of the E-plane through a metal plate 400 or a short-circuit pin to suppress the edge truncation effect.

[0069] As an embodiment, the height of the auxiliary radiating arm is determined based on the heights of the first radiating arm 200 and the second radiating arm 300; and the width of the auxiliary radiating arm is adjusted based on the active standing wave ratio of the first and last antenna units of the E-plane.

[0070] As a specific example, Figure 4 As shown, auxiliary radiation arms are added to the side of the short-circuit pins of the head antenna unit 1 and the end antenna unit 8. More specifically, the width s3 of the auxiliary radiation arm is s3=18 mm, which is adjusted according to the active standing wave ratio of the head antenna unit 1 and the end antenna unit 8. The height of the auxiliary radiation arm is equal to the height of the first radiation arm 200 and the second radiation arm 300 of the antenna unit.

[0071] The width of the auxiliary radiating arm is adjusted based on the active standing wave ratio of the first and last antenna units of the E-plane. Furthermore, the width of the auxiliary radiating arm can be adjusted according to the active standing wave ratio of all antenna units of the E-plane, or according to the active standing wave ratio of the first and last antenna units and the antenna units randomly selected in the middle of the array.

[0072] For example, obtain the active standing wave ratio curves of antenna units 1, 3, 5, and 8, such as Figure 5 As shown, from Figure 5(b) and (c) show that as the width of the auxiliary radiation arm increases, the active standing wave ratio of the two relatively central antenna units in the one-dimensional E-plane antenna array, namely antenna unit 3 and antenna unit 5, has almost no change. The only change is a slight improvement in the matching of antenna unit 5 at around 2 GHz. Increasing the width of the radiation arm has a greater impact on the two antenna units at the edge. Figure 5 As shown in (a), when s3 increases from 0 to 6 mm, that is, by increasing the radiation arm, the active standing wave ratio of antenna unit 1 is significantly improved, and by further increasing the width, the operating frequency of antenna unit 1 is reduced to 0.8 GHz. For antenna unit 8, as the auxiliary radiation arm becomes wider, the active standing wave ratio is significantly improved. When s3 increases to 18 mm, the active standing wave ratio of antenna unit 8 after 1.68 GHz is lower than 2, but when s3 is further increased, the active standing wave ratio at the low frequency end deteriorates. Therefore, after comprehensive consideration, the width s3 of the auxiliary radiation arm is determined to be 18 mm.

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

[0074] As an embodiment, in order to suppress the leakage of side radiation, a short-circuit strip connected to the ground is provided on the end antenna unit of the E-plane. In the one-dimensional E-plane antenna array, only antenna unit 8 is loaded with the short-circuit strip, and the other antenna units are still the structure of the antenna unit. 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, Figure 4 As shown, a short-circuit strip connected to the ground is loaded at the end of one arm of the antenna unit 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 of the Vivaldi antenna array is such as Figure 6 As shown, it can be seen that the active standing wave ratio of antenna unit 8 has been significantly improved, and its lower limit frequency is basically the same as other array elements, while other antenna units have not changed. The operating frequency band of the one-dimensional E-plane antenna array is 0.8-12GHz (15:1).

[0076] As an embodiment, when multiple antenna units are extended and arrayed along the H plane, the spacing between the antenna units on the H plane is equal to the spacing between the antenna units on the E plane.

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

[0078] During simulation, the four surfaces along the y-axis and z-axis are set as free space open boundaries, and the two surfaces along the x-axis are set as periodic boundaries. Figure 8 As shown, it can be seen that the H-plane antenna array has no obvious edge truncation effect, and each antenna unit in the antenna array maintains the superior characteristics of a single antenna unit, and the consistency is good. The operating frequency band of the antenna array is 0.8-12GHz. At the same time, it can be found that although the overall structure is not symmetrical, the active standing wave ratios of the two antenna units opposite to each other along the y-axis are basically the same.

[0079] As a specific embodiment, based on a one-dimensional E-plane Vivaldi antenna array, it is extended along the y-axis to obtain a finite antenna array. Fig. 9 As shown, a schematic diagram of an 8×8 antipodal Vivaldi antenna array provided by the present invention and the corresponding antenna unit numbering are shown, and a performance analysis is performed on the array.

[0080] The impedance matching performance is analyzed. Since the antenna array is not an axisymmetric structure, and the performance of the H-plane antenna array is relatively symmetrical, half of the units in the antenna array, such as Fig. 9 The active standing wave ratio of the antenna units 1 to 32 shown in FIG. Fig.10 As shown, Fig.10 (ad) are the active standing wave ratio results of antenna units 1 to 8, 9 to 16, 17 to 24, and 25 to 32. It can be seen that the performance of each antenna unit in the antenna array is good. In the working frequency band of 0.82-12GHz (14.6:1), the active standing wave ratio is basically less than 2. At this time, the corresponding antenna unit size is 0.04λ l / 0.54λ h Although the active standing wave ratio of antenna unit 8 at the low frequency end deteriorates to a certain extent, mainly due to the E-plane edge truncation effect that cannot be completely suppressed, the active standing wave ratio is still lower than 2.2 as a whole, and also has good performance.

[0081] Analyze the far-field radiation performance. Fig.11 As shown in Figure 1, the normal gain and aperture efficiency of the 8×8 antipodal Vivaldi antenna array are given. Fig.11 (a) also gives the theoretical value curve. It can be seen that the normal gain within the antenna array band is very close to the theoretical value, so its aperture efficiency reaches more than 80% within the band. At the same time, the normal gain curve decreases after 13GHz, verifying the upper limit of the operating frequency of the antenna array.

[0082] Fig.12 and Fig.13 The directional patterns of the antenna array when scanning on the E plane and H plane are given respectively. The antenna array has better scanning performance at low frequencies.

[0083] At 1GHz, the gain changes during scanning of the E-plane and H-plane are within 1.1dB and 0.2dB respectively. When the antenna array scans in the space where the -x axis is located, the half-power beam width of the E-plane pattern increases with the increase of the scanning angle; when scanning in the space where the +x axis is located, the half-power beam width first decreases and then increases, but both are greater than 60°, and the maximum value of 73.6° occurs when scanning to -60°. The change trend of the half-power beam width of the H-plane pattern in the space where the +y and -y axes are located is the same as that of the E-plane in the space where the -x and +x axes are located. The half-power beam width of the E-plane is larger than that of the H-plane, mainly because the size of the E-plane of the array is larger than that of the H-plane. The sidelobe levels of the E-plane and H-plane scanning patterns increase with the increase of the scanning angle, but both remain below -10dB. At 4GHz, the gain changes of the E-plane and H-plane when scanning are within 2.0dB, and the half-power beamwidth of the H-plane pattern increases with the increase of the scanning angle, while that of the E-plane increases first and then decreases. The sidelobe levels of the E-plane and H-plane scanning patterns increase with the increase of the scanning angle. At the same time, at 8GHz, the gain changes of the E-plane and H-plane when scanning are within 2.4dB and 2.8dB respectively, and the half-power beamwidth of the H-plane pattern increases with the increase of the scanning angle. The E-plane shows an overall increasing trend, but there is a significant decrease when scanning to -45°, only 18.9°. The sidelobe levels of the H-plane scanning patterns increase with the increase of the scanning angle, while the sidelobe levels of the E-plane are relatively consistent during scanning. At 12GHz, the gain changes of the E-plane and H-plane scanning are within 2.5dB and 2.2dB respectively. The half-power beamwidth of the H-plane pattern increases with the increase of the scanning angle, while the E-plane first increases and then decreases when scanning in the space where the +x axis is located, and also decreases at -45° when scanning in the space where the -x axis is located, and is only 15.8°. Similarly, the sidelobe levels of the E-plane and H-plane scanning patterns increase with the increase of the scanning angle, and the patterns deteriorate. In general, the antenna array maintains a good radiation direction during scanning, and the gain change is always maintained within 3dB, so the antenna array has a good scanning capability.

[0084] In summary, by constructing an edge-loaded 8×8 finite antipodal Vivaldi antenna array, it is verified that the active standing wave ratio 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 ±60° beam scanning. The constructed antenna array has wide bandwidth and angle scanning capability.

[0085] It should be noted that, for the above-mentioned various embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, and according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0086] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. In the several embodiments provided in this application, it should be understood that the disclosed method or system can be implemented in other ways. For example, the embodiments described above are only schematic, such as the division of the units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

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

[0088] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0089] The above is only an exemplary embodiment of the present disclosure, and the scope of the present disclosure cannot be limited thereto. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure here, those skilled in the art will easily think of the implementation scheme of the present disclosure. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the technical field not recorded in the present disclosure. The description and examples are regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

[0090] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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] It will be easily understood by those skilled in the art that the above description is only 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 in the protection scope of the present invention.

Claims

1. An edge-loaded tightly coupled broadband antipodal Vivaldi antenna array, comprising one or more antenna units; the antenna unit comprises a dielectric plate, a first radiating arm and a second radiating arm; the first radiating arm and the second radiating arm are arranged on the dielectric plate; It is characterized in that The antenna unit also includes a metal plate; The metal plate partially overlaps with 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 opening width of the outer exponential curve and the opening width of the inner exponential curve of the antenna unit.

2. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 1, It is characterized in that The metal plate is provided with a plurality of metal vias for loading short-circuit pins.

3. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 2, It is characterized in that The metal vias are arranged in equal intervals or unequal intervals.

4. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 2, It is characterized in that The antenna unit has an operating frequency of 0.7 to 20 GHz and a size of 0.03λ l / 0.9λ h ; Among them, λ l and λ h They respectively represent the lowest frequency and the highest frequency corresponding to the working frequency band.

5. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 1, It is characterized in that When multiple antenna units are extended and arrayed along the E-plane, adjacent antenna units are connected via the metal plate or the short-circuit pins.

6. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 5, It is characterized in that The antenna array also includes an auxiliary radiation arm, which is connected to the first and last antenna units of the E-plane through the metal plate or the short-circuit pin, so as to suppress the edge truncation effect.

7. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 6, It is characterized in that The height of the auxiliary radiating arm is determined based on the heights of the first radiating arm and the second radiating arm; and the width of the auxiliary radiating arm is adjusted based on the active standing wave ratio of the first and last end antenna units of the E-plane.

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

9. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 8, It is characterized in that The width of the short-circuit strip is less than or equal to the width of the metal plate.

10. The edge-loaded tightly coupled broadband antipodal Vivaldi antenna array according to claim 5, It is characterized in that When multiple antenna units are extended and arrayed along the H plane, the spacing between the antenna units on the H plane is equal to the spacing between the antenna units on the E plane.

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