Integrated phased array antenna for broadband radar cross section reduction

Abstract

The invention discloses an integrated phased-array antenna for reducing the scattering cross section of a broadband radar. The phased-array antenna is formed by periodically arranging M * N array antenna unit structures, the array antenna unit structure comprises a loss layer and an antenna layer, the loss layer and the antenna layer are separated by an air layer, and the loss layer and the antenna layer are supported by nylon columns. By adopting the technical scheme of the invention, the ultra-wideband radar cross section (RCS) reduction characteristic is realized, and the probability that a target is detected by a radar can be effectively reduced in a wideband range; + / -45-degree flexible beam scanning capability is realized, and large-range space detection coverage can be realized; and the wide-angle optical system has good angle stability, and can still keep stable and reliable performance in a wide incident angle range.

Description

Technical Field

[0001] The present invention belongs to the technical field of radar antennas, and particularly relates to an integrated phased array antenna for broadband radar cross-section reduction. Background Art

[0002] Radar detection technology plays a crucial role in modern military warfare. The accompanying radar cross-section (RCS) reduction technology is indispensable in stealth applications. Metamaterials and metasurfaces have flexible electromagnetic regulation capabilities and are effective ways to achieve RCS reduction.

[0003] The methods of RCS reduction include active cancellation, shaping method, electromagnetic absorption, and passive cancellation. Among them, the electromagnetic absorption method includes converting incident electromagnetic waves into surface waves and using resistors for absorption. The structure for converting incident electromagnetic waves into surface waves is generally a three-dimensional structure, which is relatively complex. The RCS reduction bandwidth of traditional electromagnetic absorption methods is relatively narrow, the structure is complex, and the angular stability is limited. The passive cancellation methods mainly include coded metasurfaces, phase gradient metasurfaces, checkerboard metasurfaces, dartboard metasurfaces, etc. Among them, the RCS reduction bandwidth of coded metasurfaces and phase gradient metasurfaces is limited. Phase cancellation and polarization conversion are the main RCS reduction mechanisms of checkerboard metasurfaces. The former principle is to achieve backward RCS reduction by having a phase difference of 180° ± 37° between different scattered waves. The latter principle is to convert the energy of the incident wave into the cross-polarization component, thereby achieving co-polarization RCS reduction. However, many existing passive cancellation methods cannot simultaneously achieve ultra-wideband RCS reduction and wide-angle stability.

[0004] In summary, it is difficult to simultaneously achieve broadband RCS reduction, have a flexible beam scanning ability of ±45°, and have good angular stability. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an integrated phased array antenna for broadband radar cross-section reduction.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] An integrated phased array antenna for broadband radar cross-section reduction is composed of M×N array antenna unit structures arranged periodically to form a phased array antenna; the array antenna unit structure includes: a loss layer and an antenna layer, the loss layer and the antenna layer are separated by an air layer, and nylon columns are used for support between the loss layer and the antenna layer.

[0008] Preferably, the antenna layer includes: a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, a first metal floor, a fourth dielectric substrate, a fifth dielectric substrate, and a second metal floor that are connected in sequence; a first radiation layer is provided between the first dielectric substrate and the second dielectric substrate, a second radiation layer is provided between the second dielectric substrate and the third dielectric substrate, and an impedance matching network layer is provided between the fourth dielectric substrate and the fifth dielectric substrate.

[0009] Preferably, the loss layer includes a sixth dielectric substrate, on which metal wires and four chip resistors are provided. The metal wires are composed of four square metal rings and a circular metal ring in the middle that are interconnected. The four chip resistors are arranged on the metal ring, and the chip resistors are used to match the wave impedance in free space to achieve broadband absorption.

[0010] Preferably, the impedance matching network layer includes: a strip line impedance matching network of short-circuited lines and open-circuited lines. The length L s of the short-circuited line ranges from 3 to 4 mm, and the width W s ranges from 0.1 to 0.2 mm. The length L o of the open-circuited line ranges from 2 to 3 mm, and the width W o ranges from 2 to 3 mm.

[0011] Preferably, the width W1 of the gap at the connection between the metal square ring and the metal circular ring in the loss layer ranges from 0.1 to 0.5 mm, the length L1 ranges from 1 to 3 mm, the outer diameter R1 of the metal circular ring ranges from 3 to 3.7 mm, the inner diameter R2 ranges from 2 to 3 mm, the outer length W2 of the metal square ring ranges from 3.5 to 5.5 mm, and the inner length L2 ranges from 2.5 to 4.5 mm.

[0012] Preferably, the length and width P of the unit structure of the loss layer and the antenna layer are both 20 mm. The height range of the loss layer is 1 - 2 mm, and the height h air of the air layer ranges from 7 to 9 mm.

[0013] Preferably, the overall height range of the antenna layer is 6 - 8 mm; among them, the height h1 of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate in the antenna layer is 2 mm, and the height h2 of the fourth dielectric substrate and the fifth dielectric substrate is 0.5 mm.

[0014] Preferably, the package model of the chip resistor is 0402. The length of the resistor is 1 mm, the width is 0.5 mm, and the resistance value of the chip resistor is 100 Ω.

[0015] Preferably, the structure of the first radiation layer is: the length and width are both in the range of p1 from 10 to 11 mm, and the thickness is 0.018 mm. The structure of the second radiation layer is: the length and width are both in the range of p2 from 13 to 14 mm, and the thickness is 0.018 mm.

[0016] Preferably, the metal materials on the loss layer and the antenna layer are both copper, and the thickness of both is 0.018 mm.

[0017] The integrated phased array antenna of the present invention has excellent performance: First, it has the characteristic of reducing the radar cross section (RCS) in an ultra-wideband, and can effectively reduce the probability of a target being detected by a radar within a wide frequency band range; Second, it has a flexible beam scanning ability of ±45°, and can achieve a large range of spatial detection coverage; Third, it has good angular stability, and can still maintain stable and reliable performance within a relatively wide range of incident angles. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0019] Figure 1 It is a schematic structural diagram of the integrated phased array antenna for broadband radar cross section reduction in the embodiment of the present invention;

[0020] Figure 2 It is a schematic structural diagram of the array antenna element;

[0021] Figure 3 It is a schematic structural diagram of the loss layer;

[0022] Figure 4 It is a schematic structural diagram of the antenna layer;

[0023] Figure 5 It is a schematic structural diagram of the impedance matching network layer;

[0024] Figure 6 It is the reflection coefficient of the unit structure of the present invention;

[0025] Figure 7 It is the transmission coefficient and absorption rate of the unit structure of the present invention;

[0026] Figure 8 It is a schematic diagram of the single-station RCS reduction result of the present invention compared with a metal floor of the same size at normal incidence; among them, (a) is a schematic diagram of the RCS reduction result in the x polarization, and (b) is a schematic diagram of the RCS reduction result in the y polarization.

[0027] Figure 9 It is a schematic diagram of the comparison of the 3D scattering pattern of the present invention with a metal floor of the same size at normal incidence;

[0028] Figure 10 Schematic diagram of the bistatic RCS reduction of the present invention when obliquely incident and a metal floor of the same size; wherein, (a) is the schematic diagram of the bistatic RCS reduction when the incident angle is 5°, (b) is the schematic diagram of the bistatic RCS reduction when the incident angle is 10°, (c) is the schematic diagram of the bistatic RCS reduction when the incident angle is 15°, and (d) is the schematic diagram of the bistatic RCS reduction when the incident angle is 20°;

[0029] Figure 11 Schematic diagram of the gain of the present invention varying with frequency;

[0030] Figure 12 Schematic diagram of the beam scanning of the present invention at 6.5 GHz; wherein, (a) is the schematic diagram of the beam scanning in the xoz plane, and (b) is the schematic diagram of the beam scanning in the yoz plane. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0033] Embodiment 1:

[0034] As shown in Figure 1 、 2 、4, the embodiment of the present invention provides an integrated phased array antenna for broadband radar cross-section reduction, which is composed of M×N array antenna unit structures arranged periodically to form a phased array antenna; the array antenna unit structure includes: a loss layer and an antenna layer, the loss layer and the antenna layer are separated by an air layer, and nylon columns are used to support between the loss layer and the antenna layer. The antenna layer includes: a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, a first metal floor, a fourth dielectric substrate, a fifth dielectric substrate, and a second metal floor connected in sequence; a first radiation layer is provided between the first dielectric substrate and the second dielectric substrate, a second radiation layer is provided between the second dielectric substrate and the third dielectric substrate, and an impedance matching network layer is provided between the fourth dielectric substrate and the fifth dielectric substrate. The loss layer includes a sixth dielectric substrate, on which metal wires and 4 patch resistors are provided. The metal wires are composed of four square metal rings and a circular metal ring in the middle connected to each other. The 4 patch resistors are arranged on the metal ring, and the patch resistors are used to match the wave impedance in free space to achieve broadband absorption.

[0035] The length and width P of the unit structures of the loss layer and the antenna layer are both 20 mm, the height range of the loss layer is 1 - 2 mm, and the height h of the air layer air ranges from 7 - 9 mm, and the overall height range of the antenna layer is 6 - 8 mm. The heights h1 of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate in the antenna layer are all 2 mm, and the heights h2 of the fourth dielectric substrate and the fifth dielectric substrate are all 0.5 mm. The loss layer adopts a combination form of metal and resistor, and the metal shape of the loss layer is a metal square ring and a metal circular ring. The metal materials on the loss layer and the antenna layer are both copper, and the thicknesses are both 0.018 mm. The loss layer absorbs electromagnetic waves outside the operating frequency band of the antenna and can transmit electromagnetic waves within the operating frequency band of the antenna, ensuring that the radiation performance of the antenna does not decrease significantly.

[0036] The package model of the chip resistor is 0402, the length of the resistor is 1 mm, the width is 0.5 mm, and the resistance value of the chip resistor is 100 Ω.

[0037] The overall size of the integrated phased array in the horizontal direction is 160×160 mm 2 , and the overall thickness is 16.5 mm. Under the condition of perpendicular incidence of electromagnetic waves, the integrated phased array can achieve an average RCS monostatic reduction of 14.6 dB in a broadband frequency band of 3.3 - 9.4 GHz, and this reduction frequency band covers the in-band operating frequency band and the out-of-band operating frequency band. At the same time, under the condition of oblique incidence of electromagnetic waves, the integrated phased array has angular stability in terms of RCS reduction.

[0038] The relative permittivity, thickness of the dielectric substrate, and the thickness of the air layer and the specific dimensions of the metal layer are determined according to the operating frequency and bandwidth. The dielectric substrate material used in the embodiments of the present invention is F4B, the relative permittivity is ε r = 2.2, and the loss tangent is tanδ = 0.001.

[0039] As Figure 3 shown, the range of the gap width W1 at the connection between the metal square ring and the metal circular ring in the loss layer is 0.1 - 0.5 mm, the range of the length L1 is 1 - 3 mm, the range of the outer diameter R1 of the metal circular ring is 3 - 3.7 mm, the range of the inner diameter R2 is 2 - 3 mm, the range of the outer length W2 of the metal square ring is 3.5 - 5.5 mm, and the range of the inner length L2 is 2.5 - 4.5 mm.

[0040] As Figure 4 shown, the structure of the first radiation layer is: the range of the length and width p1 is 10 - 11 mm, and the thickness is 0.018 mm. The structure of the second radiation layer is: the range of the length and width p2 is 13 - 14 mm, and the thickness is 0.018 mm.

[0041] AsFigure 5 As shown, the impedance matching network layer includes: a strip line impedance matching network of a short circuit line and an open circuit line, and the length L of the short circuit line s ranges from 3 to 4 mm, and the width W s ranges from 0.1 to 0.2 mm. The length L of the open circuit line o ranges from 2 to 3 mm, and the width W o ranges from 2 to 3 mm.

[0042] In an embodiment of the present invention, as Figure 6 shown, it is the reflection coefficient of the integrated phased array unit structure. It can be seen that the operating bandwidth of the unit is from 5.5 GHz to 7.5 GHz. As Figure 7 shown, it is the transmission coefficient and wave absorption rate of the integrated phased array unit. The unit can achieve better wave absorption in the operating frequency bands of 4 GHz to 4.9 GHz and 7.8 GHz to 9.3 GHz, and can achieve good wave transmission in the operating frequency range of 5.5 GHz to 7.5 GHz, ensuring that the radiation performance of the antenna is not affected.

[0043] In an embodiment of the present invention, Figure 8 shown is the monostatic RCS reduction of the x-polarization and y-polarization of the simulated integrated phased array under the condition of vertical incidence. It should be noted that the RCS reduction is the comparison result between the integrated phased array of equal size and the flat metal floor. It can be seen that for the x-polarized incident wave, broadband RCS reduction can be achieved in the frequency range from 3.3 GHz to 9.4 GHz; for the y-polarized incident wave, the loss layer can still achieve out-of-band wave absorption and thus achieve out-of-band RCS reduction, with polarization insensitivity, while the impedance matching network can only perform in-band RCS reduction on the co-polarized incident wave.

[0044] In an embodiment of the present invention, Figure 9 shown is the comparison of the three-dimensional scattering patterns of the flat metal floor and the integrated phased array of equal size at 6 GHz and 7 GHz under the condition of vertical incidence. It can be seen that compared with the RCS of the equal-sized metal plate, the integrated phased array can achieve a large reduction in RCS at different frequencies.

[0045] In an embodiment of the present invention, Figure 10 shown is the RCS reduction of the simulated integrated phased array in the mirror direction of TE polarization under the condition of oblique incidence. Under oblique incidence, the xoz plane is selected as the incident plane (azimuth angle φ i = 0), and the elevation angles with different incident angles are respectively θ i = 5°, 10°, 15°, 20°. Under TE polarization, the integrated phased array can achieve broadband RCS reduction at different incident angles and has angle stability.

[0046] In one embodiment of the present invention, Figure 11 The figure shows the curves of the gain of the integrated phased array with a lossy layer and the phased array without a lossy layer varying with frequency. It can be seen that the two curves almost coincide, indicating that the integrated phased array can work normally within the operating frequency band and the lossy layer has no obvious impact on the antenna. Figure 12 The figure shows the beam scanning performance of the integrated phased array in the xoz plane and the yoz plane. It can be seen that the integrated phased array can achieve beam scanning within the range of ±45° in both the xoz plane and the yoz plane, and the main board gain attenuation does not exceed 3 dB, and the maximum sidelobe level is lower than -10 dB.

[0047] The above-described embodiments are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. An integrated phased array antenna for reducing broadband radar cross section, characterized in that, A phased array antenna is composed of a periodic arrangement of M×N array antenna unit structures; The array antenna unit structure includes: a loss layer and an antenna layer. The loss layer and the antenna layer are separated by an air layer, and nylon columns are used for support between the loss layer and the antenna layer.

2. The integrated phased array antenna for reducing broadband radar cross section according to claim 1, characterized in that The antenna layer includes: a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, a first metal floor, a fourth dielectric substrate, a fifth dielectric substrate, and a second metal floor connected in sequence; a first radiation layer is provided between the first dielectric substrate and the second dielectric substrate, a second radiation layer is provided between the second dielectric substrate and the third dielectric substrate, and an impedance matching network layer is provided between the fourth dielectric substrate and the fifth dielectric substrate.

3. The integrated phased array antenna for reducing broadband radar cross section according to claim 2, characterized in that The loss layer includes a sixth dielectric substrate. A metal wire and 4 chip resistors are provided on the sixth dielectric substrate. The metal wire is composed of four square metal rings and a circular metal ring in the middle connected to each other. The 4 chip resistors are arranged on the metal ring. The chip resistors are used to match the wave impedance in free space to achieve broadband absorption.

4. The integrated phased array antenna for reducing broadband radar cross section according to claim 3, characterized in that, The impedance matching network layer includes: a strip line impedance matching network of a short circuit line and an open circuit line, and the length L of the short circuit line s ranges from 3 to 4 mm, and the width W s ranges from 0.1 to 0.2 mm. The length L of the open circuit line o ranges from 2 to 3 mm, and the width W o ranges from 2 to 3 mm.

5. The integrated phased array antenna for reducing broadband radar cross section according to claim 4, characterized in that, The range of the gap width W1 at the connection between the metal square ring and the metal ring in the loss layer is 0.1 - 0.5 mm, the range of the length L1 is 1 - 3 mm, the range of the outer diameter R1 of the metal ring is 3 - 3.7 mm, the range of the inner diameter R2 is 2 - 3 mm, the range of the outer length W2 of the metal square ring is 3.5 - 5.5 mm, and the range of the inner length L2 is 2.5 - 4.5 mm.

6. The integrated phased array antenna for broadband radar cross section reduction according to claim 5, characterized in that The length and width P of the unit structures of the lossy layer and the antenna layer are both 20 mm, the height range of the lossy layer is 1 - 2 mm, and the height h air of the air layer ranges from 7 - 9 mm.

7. The integrated phased array antenna for reducing broadband radar cross section according to claim 6, characterized in that, The overall height range of the antenna layer is 6 - 8 mm; among them, the height h1 of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate in the antenna layer is 2 mm each, and the height h2 of the fourth dielectric substrate and the fifth dielectric substrate is 0.5 mm each.

8. The integrated phased array antenna for broadband radar cross-section reduction according to claim 7, characterized in that, The package model of the chip resistor is 0402. The length of the resistor is 1 mm, the width is 0.5 mm, and the resistance value of the chip resistor is 100 Ω.

9. The integrated phased array antenna for broadband radar cross section reduction according to claim 8, characterized in that, The structure of the first radiation layer is: the length and width p1 are both in the range of 10 - 11 mm, and the thickness is 0.018 mm. The structure of the second radiation layer is: the length and width p2 are both in the range of 13 - 14 mm, and the thickness is 0.018 mm.

10. The integrated phased array antenna for broadband radar cross section reduction according to claim 9, wherein, The metal materials on the loss layer and the antenna layer are both copper, and the thicknesses are both 0.018 mm.

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