One-dimensional tight coupling phased array with low cross polarization

Abstract

The invention relates to a one-dimensional tight coupling phased array with low cross polarization, which comprises a plurality of periodic units, and is characterized in that each periodic unit comprises a horizontal polarization interdigitated dipole, a vertical polarization interdigitated dipole, a feed structure and a first metal floor; the horizontal polarization interdigital dipole and the vertical polarization interdigital dipole are respectively printed on the upper layer and the lower layer of the dielectric plate and are orthogonally arranged; feed ports of the horizontal polarization interdigital dipoles are symmetrically distributed with respect to the center line of the pitching plane. The feed ports of the vertical polarization interdigital dipoles are arranged in a staggered manner on the central line of the pitching surface; the feed structure is used for feeding the horizontally and vertically polarized interdigitated dipoles; the first metal floor is a reflection floor of the horizontal polarization interdigitated dipole and the vertical polarization interdigitated dipole. Through the symmetrical design of the array feed ports, the radiator has good symmetry, the current path is optimized, the current component causing cross polarization is reduced, and the antenna has a low cross polarization level.

Description

Technical Field

[0001] The invention belongs to the field of microwave and antenna technology, and specifically relates to a one-dimensional tightly coupled phased array in the field of antenna technology, which can be used for long-distance communication or interference. Background Art

[0002] The advantages of array antennas are that they are easy to achieve special needs such as strong directivity, high power, beam controllability, low side lobes and shaped beams. As a form of array antenna, tightly coupled arrays are very consistent with the development direction of phased array radars due to their advantages such as ultra-wideband, low profile, and easy conformality, and are receiving more and more attention. Conventional tightly coupled arrays are arranged in two dimensions. The reason is that tightly coupled arrays rely on capacitive coupling between units to slow down impedance changes and achieve broadband design. However, for some special applications, such as airborne narrow and long environments, it is impossible to design a two-dimensional array, which limits its application. Therefore, one-dimensional tightly coupled arrays are a direction worth studying and have high application value.

[0003] Yang Shiwen's team from the University of Electronic Science and Technology of China disclosed a dual-polarized one-dimensional strongly coupled ultra-wideband scanning phased array in the patent document "A dual-polarized one-dimensional strongly coupled ultra-wideband scanning phased array" (application number 201610230021.1, application publication number CN 105846081 A). The antenna consists of two rows of horizontally polarized and 26 rows of vertically polarized interdigital coupled dipole antennas. Its basic structure includes a vertical parasitic printed dielectric plate for wide-angle scanning, an upper layer of horizontally polarized interdigital dipoles, a dielectric plate, a lower layer of vertically polarized interdigital dipoles and their horizontal extensions, a vertically gradient extension of the vertically polarized dipole, a gradient microstrip line feeding structure for feeding at the dipole port, a reflective floor, metal fences on both sides of the floor, a power divider, and a 50-ohm coaxial adapter. Among them, the tight coupling structure between units helps the antenna achieve ultra-wideband effect; the parasitic printed dielectric board is used instead of the bulky traditional wide-angle impedance matching layer to achieve wide-angle scanning function, while achieving a lightweight design effect. Although the antenna has transformed the strongly coupled two-dimensional array into a one-dimensional one, which has broadened the application scenarios, the shortcoming of the antenna is that it does not consider the influence of cross-polarization. The cross-polarization characteristic is also a key indicator of the dual-polarization antenna, which directly determines the polarization purity of the antenna and the communication quality of the entire system.

[0004] The 724th Research Institute of China Shipbuilding Industry Corporation disclosed an ultra-wide bandwidth angle coverage low cross-polarization array antenna unit in its patent application "An ultra-wide bandwidth angle coverage low cross-polarization array antenna unit" (application number 201810764050.5, application publication number CN 108899639 A). The array antenna unit includes the following parts: a dielectric substrate part, a gradient opening slot line part, a parasitic elliptical metal strip part, a metallized through-hole part, a stripline balun feeding part and a metal guide part. The antenna radiation unit proposed in the invention has the characteristics of five-fold frequency working bandwidth, wide angle scanning, wide angle matching, easy integration with the feeding network, etc., and is suitable for phased array antenna units. The array adopts a symmetrical structure of a double-layer radiator for low cross-polarization design in the antenna design, but the disadvantage of the array antenna is that the array antenna is arranged in a two-dimensional array, which is not suitable for some special applications and will be limited in actual applications.

[0005] Therefore, one of the urgent problems to be solved in the current microwave technology field is to design a one-dimensional phased array with wide bandwidth, wide scanning angle and low cross-polarization. Such a design is expected to improve the communication quality of the entire communication system and can be used in fields such as electronic countermeasures. Summary of the invention

[0006] The technical problems to be solved by the present invention are:

[0007] In order to avoid the shortcomings of the prior art, the present invention provides a one-dimensional tightly coupled phased array with low cross-polarization, which is used to reduce the impact of cross-polarization on antenna performance and improve the communication quality of the entire communication system.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] A one-dimensional tightly coupled phased array with low cross-polarization, characterized in that it comprises a plurality of periodic units, each periodic unit comprises a horizontally polarized interdigital dipole, a vertically polarized interdigital dipole, a feeding structure, and a first metal floor;

[0010] The horizontally polarized interdigital dipole is printed on the upper layer of the first dielectric plate, and the vertically polarized interdigital dipole is printed on the lower layer of the first dielectric plate, and the horizontally polarized interdigital dipole and the vertically polarized interdigital dipole are placed orthogonally to each other; the feeding ports of the horizontally polarized interdigital dipole are symmetrically distributed about the center line of the pitch plane; the feeding ports of the vertically polarized interdigital dipole are staggered on the center line of the pitch plane, that is, one column of two adjacent columns of vertically polarized interdigital dipoles is offset above the center line of the pitch plane, and the other column is offset below the center line of the pitch plane;

[0011] The feeding structure is used to feed the horizontally polarized interdigital dipole and the vertically polarized interdigital dipole;

[0012] The first metal floor is a reflection floor of horizontally polarized interdigital dipoles and vertically polarized interdigital dipoles.

[0013] A further technical solution of the present invention is that the sizes of the horizontally polarized interdigital dipole and the vertically polarized interdigital dipole are different.

[0014] A further technical solution of the present invention is as follows: the vertically polarized interdigital dipole is along the Y-axis direction, and the end of the vertically polarized interdigital dipole is connected to the vertical gradually extending portion.

[0015] A further technical solution of the present invention is as follows: the lower part of the vertical gradually extending part is bent inwards and then placed above a dielectric block, and the dielectric block is located above the first metal floor.

[0016] A further technical solution of the present invention is that the vertical gradually extending portion gradually widens from top to bottom.

[0017] A further technical solution of the present invention: the feeding structure includes an exponentially tapered feeding balun and a one-to-two power divider, wherein the upper end of the exponentially tapered feeding balun is connected to the feeding port of the horizontally polarized interdigital dipole or the feeding port of the vertically polarized interdigital dipole, and the lower end is connected to the output port of the one-to-two power divider.

[0018] A further technical solution of the present invention is as follows: the one-to-two power divider is located on a second dielectric plate, and a second metal floor is provided below the second dielectric plate.

[0019] A further technical solution of the present invention is as follows: a circular through hole for installing a 50-ohm RF connector is provided on the second metal floor to avoid the square groove of the exponential gradient feeding balun.

[0020] A further technical solution of the present invention is as follows: the first metal floor is provided with a square hole for passing the exponential gradient balun.

[0021] A further technical solution of the present invention also includes a ferrite absorbing material, and the ferrite absorbing material is located above the first metal plate.

[0022] The beneficial effects of the present invention are:

[0023] The one-dimensional tightly coupled phased array with low cross-polarization provided by the present invention has the following advantages compared with the prior art:

[0024] First, the present invention adds a sheet metal structure extending vertically downward at the end of the vertically polarized cross-digital dipole to reduce the truncation effect of the one-dimensional linear array on the vertical polarization, thereby ensuring the impedance bandwidth of the vertically polarized array and achieving broadband matching. At the same time, the structure is made of sheet metal, has high strength, and has a good supporting effect on the antenna radiation layer.

[0025] Second, the present invention has symmetrically designed the vertically polarized cross-digital dipole, and its feeding port is staggered up and down on the pitch plane, and is approximately located in the center of the linear array as a whole, which is a symmetrical distribution; at the same time, the feeding port of the horizontally polarized dipole unit is arranged in the center of the pitch plane. Through this symmetrical design of the array feeding port, the radiator has better symmetry, the current path is optimized, the current asymmetry caused by the asymmetry of the radiator is minimized as much as possible, and the cross polarization of the antenna is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0027] Figure 1 This is a schematic diagram of a 2*18 linear array of a low cross-polarization tightly coupled phased array of the present invention;

[0028] Figure 2 It is a schematic diagram of a periodic unit of the low cross-polarization tightly coupled phased array of the present invention;

[0029] Figure 3 It is an exploded diagram of a period unit of the low cross-polarization tightly coupled phased array of the present invention;

[0030] Figure 4 It is a schematic diagram of a radiator in a period unit of a low cross-polarization tightly coupled phased array of the present invention;

[0031] Figure 5 It is a side view of a periodic unit of the low cross-polarization tightly coupled phased array of the present invention;

[0032] FIG6( a ) is a graph showing the active standing wave ratio of the horizontal polarization port of the low cross-polarization tightly coupled phased array of the present invention at beam scanning angles of 0 degrees, 30 degrees and 52 degrees respectively;

[0033] FIG6( b ) is a graph showing the active standing wave ratio of the vertical polarization port of the low cross-polarization tightly coupled phased array of the present invention at beam scanning angles of 0 degrees, 30 degrees and 52 degrees respectively;

[0034] FIG. 7( a ) is a cross-polarization ratio result diagram of the low cross-polarization tightly coupled phased array horizontal polarization array of the present invention at beam scanning angles of 0 degrees, 30 degrees and 52 degrees respectively;

[0035] FIG7( b ) is a diagram showing the cross-polarization ratio results of the low cross-polarization tightly coupled phased array vertical polarization array of the present invention at beam scanning angles of 0 degrees, 30 degrees and 52 degrees respectively;

[0036] FIG8( a ) is a scanning pattern of the horizontal polarization array of the low cross-polarization tightly coupled phased array of the present invention at frequencies of 0.35 GHz and 2 GHz;

[0037] FIG8( b ) is a scanning pattern of the low cross-polarization tightly coupled phased array vertical polarization array of the present invention at frequencies of 0.35 GHz and 2 GHz.

[0038] In the figure:

[0039] 1-first dielectric plate; 2-horizontally polarized interdigital dipole; 3-vertically polarized interdigital dipole; 4-vertical gradient extension portion; 5-dielectric block; 6-exponential gradient feed balun; 7-ferrite absorbing material; 8-first metal floor; 9-one-to-two power divider; 10-second dielectric plate; 11-second metal floor; 12-50 ohm RF connector; 101-first feeding port; 102-second feeding port; 103-third feeding port; 104-fourth feeding port; 201-fifth feeding port; 202-sixth feeding port; 203-seventh feeding port; 204-eighth feeding port; 901-input port; 902-second output port; 903-third output port; 1101-cylindrical through hole; 1102-square slot. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0041] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0042] The idea of ​​achieving the purpose of the present invention is that the present invention prints a horizontally polarized interdigital dipole on the top of the first dielectric plate, and prints a vertically polarized interdigital dipole on the bottom of the first dielectric plate, and the two polarized dipoles are placed orthogonally. The scale of the horizontally polarized interdigital dipole is 2*18, and the scale of the vertically polarized interdigital dipole is 2*18. The two co-polarized feeding ports along the pitch plane are combined through an exponentially tapered feeding balun and a one-to-two power divider, and the exponentially tapered feeding balun can realize the conversion from unbalanced feeding to balanced feeding. The end of the vertically polarized interdigital dipole extends vertically downward to extend the current path, ensure impedance matching, and reduce the influence of the truncation effect. The vertically extended portion of the vertically polarized dipole is supported by a dielectric block and placed above the first metal floor. The first metal floor is located below the center of the exponentially tapered feeding balun, and a square hole is opened inside it for passing the exponentially tapered feeding balun. The first metal floor is the reflective floor of the antenna, and the ferrite absorbing material is placed on it. The ferrite absorbing material can reduce the impact of the floor reflected wave on the input impedance and reduce the difficulty of impedance matching. The second metal floor is the metal ground of the one-to-two power divider, and the second dielectric plate is placed directly above the second metal floor.

[0043] The present invention arranges vertically polarized cross-digital dipoles in a staggered manner along the pitch plane, that is, one column of two adjacent vertically polarized dipoles is offset above the center line, and the other column is offset below the center line. When the number of array elements is sufficient, it can be approximately considered that the vertically polarized cross-digital dipoles are arranged in the center of the pitch plane. The horizontally polarized cross-digital dipoles are arranged along the center of the pitch plane. Through this centrally symmetrical placement, the low cross-polarization design of the antenna is achieved under the premise of ensuring that the impedance bandwidth of the standing wave is less than 2 is 140.4%. Within the scanning angle range of ±52°, the cross-polarization ratio of the horizontal polarization (cross-polarization (dB)-main polarization (dB)) is less than -35dB, the cross-polarization ratio of the vertical polarization is less than -27.5dB, and the minimum value of the cross-polarization ratio in the frequency band can reach -52.5dB.

[0044] In order to enable those skilled in the art to better understand the present invention, the present invention is described in detail below in conjunction with specific embodiments.

[0045] The application scenario of the example of the present invention is long-distance communication or interference.

[0046] Reference Figure 1 , the simulation array model of the low cross-polarization tightly coupled phased array of the present invention is explained. Figure 1 The array in the figure is a 2*18 linear array, where one antenna unit on each side is used as a dummy element to reduce the influence of the truncation effect. The actual fed array is a 2*16 linear array.

[0047] Reference Figure 2, the periodic unit simulation model of the low cross-polarization tightly coupled phased array of the present invention is further described. The antenna is divided into three layers, namely the first layer where the first dielectric plate 1 is located, the second layer where the first metal floor 8 is located, and the third layer where the second metal floor 11 is located.

[0048] Reference Figure 3 , an exploded diagram of a periodic unit of a low cross-polarization tightly coupled phased array of the present invention is described in more detail. One periodic unit includes four horizontally polarized interdigital dipoles 2 and four vertically polarized interdigital dipoles 3. The horizontally polarized interdigital dipoles 2 are along the X-axis direction, and the vertically polarized interdigital dipoles 3 are along the Y-axis direction. The sizes of the horizontally polarized interdigital dipoles 2 and the vertically polarized interdigital dipoles 3 are different. The horizontally polarized interdigital dipoles 2 are printed on the upper layer of the first dielectric plate 1, and the vertically polarized interdigital dipoles 3 are printed on the lower layer of the first dielectric plate 1, and the horizontally polarized interdigital dipoles 2 and the vertically polarized interdigital dipoles 3 are placed orthogonally to each other. The end of the vertically polarized interdigital dipole 3 is connected to the vertical gradually changing extension part 4, and the lower part of the vertical gradually changing extension part 4 is bent inward and placed above the dielectric block 5, and the dielectric block 5 is located above the first metal floor 8. The exponentially tapered feeding balun 6 is connected to the feeding port of the dipole at the top, and is connected to the first output port 902 and the second output port 903 of the one-to-two power divider 9 at the bottom. The one-to-two power divider 9 is printed on the upper surface of the second dielectric plate 10, and its input port is connected to the 50-ohm RF connector 12, and its output port is connected to the exponentially tapered balun 6. The second dielectric plate 10 is located above the second metal floor 11. There is a circular through hole 1101 inside the second metal floor 11 for installing the 50-ohm RF connector 12, and a square groove 1102 is used to avoid the exponentially tapered feeding balun 6. The horizontally polarized co-digital dipole 2 and the vertically polarized co-digital dipole 3 both have two feeding ports on the pitch plane. The two ports along the pitch plane direction in the same polarization are combined through the exponentially tapered balun 6 and the one-to-two power divider 9.

[0049] Reference Figure 4, the arrangement of the radiators of the periodic unit of the low cross-polarization tightly coupled phased array of the present invention is further described. The horizontally polarized co-digital dipole antenna unit 2 has four feeding ports in one periodic unit, namely the first feeding port 101, the second feeding port 102, the third feeding port 103, and the fourth feeding port 104, wherein the first feeding port 101 and the second feeding port 102 are located in the same column, the third feeding port 103 and the fourth feeding port 104 are located in the same column, and the four feeding ports are mirror-symmetrical along the center line L of the pitch plane; the vertically polarized co-digital dipole 3 has four feeding ports in one periodic unit, namely the first feeding port 101, the second feeding port 102, the third feeding port 103, and the fourth feeding port 104. There are also four feeding ports, namely the fifth feeding port 201, the sixth feeding port 202, the seventh feeding port 203, and the eighth feeding port 204, wherein the fifth feeding port 201 and the sixth feeding port 202 are located in the same column, the seventh feeding port 203 and the eighth feeding port 204 are located in the same column, the fifth feeding port 201 and the eighth feeding port 204 are mirror-symmetrical along the center line L of the pitch plane, and the sixth feeding port 202 and the seventh feeding port 203 are also symmetrical along the center line L of the pitch plane.

[0050] Reference Figure 5 , the side view of the periodic unit of the low cross-polarization tightly coupled phased array of the present invention is further described. The vertical polarization dipole vertical extension part 4 is a gradient structure, gradually widening from top to bottom, and below it is a dielectric block 5, which is between the first dielectric plate 1 and the first metal floor 8. The dielectric block 5 is installed to avoid electrical connection with the first metal floor.

[0051] The following is a detailed description of the effects of this application in conjunction with simulation:

[0052] 1. Simulation conditions

[0053] Using High Frequency Structure Simulator simulation software to simulate Figure 1 The 2*18 one-dimensional linear array shown.

[0054] 2. Simulation content

[0055] Simulation 1: Figure 1 The low cross-polarization tightly coupled phased array shown in the figure is brought into the simulation software for simulation, and the curves of the active standing wave of the horizontal polarization port changing with the frequency and the scanning angle as shown in FIG6(a) and the curves of the active standing wave of the vertical polarization port changing with the frequency and the scanning angle as shown in FIG6(b) are obtained.

[0056] from Figure 6(a) to Figure 6(b) It can be seen that the frequency range of the standing wave of the low cross-polarization tightly coupled phased array of the present invention below 3.5 is 0.35-2 GHz. It can be seen that the low cross-polarization tightly coupled phased array of the present invention has ultra-wideband characteristics.

[0057] Simulation 2: Figure 1 The low cross-polarization tightly coupled phased array shown in the figure is brought into the simulation software for simulation, and the cross-polarization ratio variation curve of the horizontal polarization array as shown in FIG7(a) and the cross-polarization ratio variation curve of the vertical polarization array as shown in FIG7(b) are obtained.

[0058] from Figure 7(a) to Figure 7(b) It can be seen that, since the horizontally polarized interdigital dipole and the vertically polarized interdigital dipole in the embodiment of the present invention have symmetric characteristics about the center line L, the low cross-polarization tightly coupled phased array of the present invention has a lower cross-polarization ratio in the working frequency band. In the range of the scanning angle of ±52°, the cross-polarization ratio of the horizontal polarization is less than -35dB, the cross-polarization ratio of the vertical polarization is less than 27.5dB, and the minimum value of the cross-polarization ratio in the frequency band can reach -52.5dB.

[0059] Simulation 3: Figure 1 The low cross-polarization tightly coupled phased array shown in the figure is brought into the simulation software for simulation, and the scanning pattern shown in FIG8 is obtained. FIG8 shows the scanning patterns of 0 degrees, 30 degrees and 52 degrees at two frequency points of 0.35 GHz and 2 GHz.

[0060] As can be seen from FIG8 , the low cross-polarization tightly coupled phased array of the present invention has good scanning performance at 0.35 GHz and 2 GHz.

[0061] The above simulation results show that the low cross-polarization tightly coupled phased array of the present invention has a lower cross-polarization ratio and better impedance matching performance within the working frequency band. Among them, within the scanning angle range of ±52°, the cross-polarization ratio of horizontal polarization is less than -35dB, the cross-polarization ratio of vertical polarization is less than -27.5dB, and the minimum cross-polarization ratio within the frequency band can reach -52.5dB. The relative bandwidth of the standing wave below 2 is 140.4%, which has good broadband characteristics.

[0062] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be included in the protection scope of the present invention.

Claims

1. A one-dimensional tightly coupled phased array with low cross-polarization, characterized in that: It comprises a plurality of periodic units, each periodic unit comprising a horizontally polarized interdigital dipole (2), a vertically polarized interdigital dipole (3), a feeding structure, and a first metal floor (8); The horizontally polarized interdigital dipole (2) is printed on the upper layer of the first dielectric plate (1), and the vertically polarized interdigital dipole (3) is printed on the lower layer of the first dielectric plate (1), and the horizontally polarized interdigital dipole (2) and the vertically polarized interdigital dipole (3) are placed orthogonally to each other; the feeding ports of the horizontally polarized interdigital dipole (2) are symmetrically distributed with respect to the center line of the elevation plane; the feeding ports of the vertically polarized interdigital dipole (3) are staggeredly arranged on the center line of the elevation plane, that is, one of two adjacent columns of vertically polarized interdigital dipoles (3) is offset above the center line of the elevation plane, and the other is offset below the center line of the elevation plane; The feeding structure is used to feed the horizontally polarized interdigital dipole (2) and the vertically polarized interdigital dipole (3); The first metal floor (8) is a reflection floor for the horizontally polarized interdigital dipole (2) and the vertically polarized interdigital dipole (3).

2. A one-dimensional tightly coupled phased array with low cross-polarization according to claim 1, characterized in that: The sizes of the horizontally polarized interdigital dipole (2) and the vertically polarized interdigital dipole (3) are different.

3. The one-dimensional tightly coupled phased array with low cross-polarization according to claim 1, characterized in that: The vertically polarized interdigital dipole (3) is along the Y-axis direction, and the end of the vertically polarized interdigital dipole (3) is connected to the vertically gradually extending portion (4).

4. The one-dimensional tightly coupled phased array with low cross-polarization according to claim 3, characterized in that: The lower part of the vertical gradually extending part (4) is bent inwards and then placed above the dielectric block (5), and the dielectric block (5) is located above the first metal floor (8).

5. A one-dimensional tightly coupled phased array with low cross-polarization according to claim 4, characterized in that: The vertical gradually extending portion (4) gradually widens from top to bottom.

6. The one-dimensional tightly coupled phased array with low cross-polarization according to claim 1, characterized in that: The feeding structure comprises an exponentially tapered feeding balun (6) and a one-to-two power divider (9), wherein the upper end of the exponentially tapered feeding balun (6) is connected to a feeding port of a horizontally polarized co-digital dipole (2) or a feeding port of a vertically polarized co-digital dipole (3), and the lower end is connected to an output port of the one-to-two power divider (9).

7. A one-dimensional tightly coupled phased array with low cross-polarization according to claim 6, characterized in that: The one-to-two power divider (9) is located on a second dielectric plate (10), and a second metal floor (11) is provided below the second dielectric plate (10).

8. A one-dimensional tightly coupled phased array with low cross-polarization according to claim 7, characterized in that: The second metal floor (11) is provided with a circular through hole (1101) for installing a 50-ohm radio frequency connector (12) and a square groove (1102) for avoiding the exponential gradient feeding balun (6).

9. The one-dimensional tightly coupled phased array with low cross-polarization according to claim 6, characterized in that: The first metal floor (8) is provided with a square hole (801) for passing the exponential gradient balun (6).

10. The one-dimensional tightly coupled phased array with low cross-polarization according to claim 1, characterized in that: It also includes a ferrite absorbing material (7), wherein the ferrite absorbing material (7) is located above the first metal plate (8).

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