A broadband wide-angle wave absorber of a planar multilayer PCB structure

Abstract

The application discloses a broadband wide-angle wave absorber of a planar multilayer PCB structure, which comprises a dual-polarized tight coupling oscillator and a matching circuit loaded with a lumped resistor on the back of the oscillator floor. The dual-polarized tight coupling oscillator is used for receiving electromagnetic waves incident on the surface of the wave absorber and transmitting the electromagnetic waves to the matching circuit on the back of the floor; the matching circuit is used for transmitting the electromagnetic wave signals to the lumped resistor without loss; and the lumped resistor is used for absorbing the electromagnetic waves. The wave absorber designed in the application has the characteristics of super wideband, low profile and polarization independence, and has stable angle characteristics. In addition, the wave absorber designed in the application can be processed by using a planar PCB process, thereby increasing the engineering practicability. The application has important application in radar cross section (RCS) reduction and the like.

Description

Technical Field

[0001] This invention belongs to the field of microwave absorbers, and in particular to a wideband, wide-angle microwave absorber with a planar multilayer PCB structure. Background Technology

[0002] Reducing radar cross-section (RCS) is crucial for detection. Absorbers can effectively reduce RCS by absorbing incoming waves. In absorber design, absorbing materials can directly absorb incident electromagnetic waves, but their large size and weight, and inability to integrate with microwave devices, limit their application scenarios. Absorbers can also be designed using frequency-selective surfaces (FSS). The Salisbury screen, as a type of frequency-selective surface, can be used to design absorbers. It achieves absorption characteristics by placing a lossy layer with resonant properties at a quarter wavelength above a metal plane; however, absorbers designed using this method have a narrow bandwidth. Jauman screens, using multi-layered structures, can generate additional resonant points to broaden their operating bandwidth, but this also increases the cross-section. Circuit simulation absorbers designed using multi-layered FSS structures can effectively broaden the operating bandwidth, but their design still requires a trade-off between bandwidth and absorber cross-section. In recent years, with the rise of metamaterials / metasurfaces, the design of absorbers based on metamaterials / metasurfaces has also received widespread attention. For example, designing absorbers using high-impedance surfaces is one of the current research hotspots. However, designing absorbers with ultra-wide bandwidth, low profile, polarization independence, and angle-stable planar PCB structures remains a difficult challenge. Summary of the Invention

[0003] The purpose of this invention is to provide a wideband, wide-angle absorber with a planar multilayer PCB structure.

[0004] The technical solution to achieve the purpose of this invention is: a broadband wide-angle absorber with a planar multilayer PCB structure, which includes a dual-polarized tightly coupled oscillator and a matching circuit with a loaded lumped resistor disposed on the back of the oscillator ground plane;

[0005] The dual-polarized tightly coupled oscillator is used to receive electromagnetic waves incident on the surface of the absorber and transmit them to the matching circuit on the back of the floor.

[0006] The matching circuit is used to transmit electromagnetic wave signals to the lumped resistor without loss.

[0007] The lumped resistance is used to absorb electromagnetic waves.

[0008] Furthermore, the dual-polarized tightly coupled vibrator includes several antenna elements, each antenna element comprising, from top to bottom, a wide-angle matching layer, a metal vibrator dielectric substrate, a support layer, and a common ground plane; a horizontal metal vibrator radiating plate and a vertical metal vibrator radiating plate located on the same horizontal plane are disposed between the wide-angle matching layer and the metal vibrator dielectric substrate, and a coupling metal disc is disposed between the metal vibrator dielectric substrate and the support layer; the coupling metal disc is connected to the common ground plane through vertical through-holes; the horizontal and vertical metal vibrator radiating plates are respectively connected to the common ground plane through a first vertical short-circuit through-hole and a second vertical short-circuit through-hole; the horizontal and vertical metal vibrator radiating plates are respectively connected to a first matching circuit and a second matching circuit through the common ground plane through a first vertical signal through-hole and a second vertical signal through-hole, respectively; the terminals of the first and second matching circuits are respectively loaded with a first lumped resistor and a second lumped resistor, and the first and second lumped resistors are respectively connected to the common ground plane through a first ground through-hole and a second ground through-hole.

[0009] Furthermore, the metal oscillator dielectric plate and support layer have a non-centrally symmetrical cross-shaped structure.

[0010] Furthermore, the horizontal metal oscillator radiating plate and the vertical metal oscillator radiating plate are respectively located on the two arms of the cross-shaped structure of the metal oscillator dielectric plate, thereby forming a non-centrally symmetrical cross-shaped structure.

[0011] Furthermore, the horizontal metal oscillator radiator and the vertical metal oscillator radiator each include two oscillator arms, one of which is the feed end and the other is grounded.

[0012] Furthermore, the coupling metal disc is disposed at the intersection of the cross structure.

[0013] Furthermore, the center of the coupling metal disc is connected to the common floor through a vertical through hole; the grounded oscillator arms of the horizontal and vertical metal oscillator radiators are respectively connected to the common floor through a first vertical short-circuit through hole and a second vertical short-circuit through hole.

[0014] Furthermore, both the first matching circuit and the second matching circuit are sections of 50-ohm microstrip lines.

[0015] Furthermore, the resistance values ​​of the first lumped resistor and the second lumped resistor are both 50 ohms.

[0016] Compared with the prior art, the significant advantages of this invention are:

[0017] (1) This invention utilizes a matching circuit with embedded lumped resistors loaded at the feed port of a dual-polarized antenna to design a broadband, wide-angle absorber with a planar PCB structure. This absorber features a low profile (0.12λ, where λ represents the wavelength at the lowest operating frequency), ultra-wide bandwidth (6-19 GHz, relative bandwidth 104%), polarization independence, and good angular stability. Furthermore, this structure can be fabricated using PCB technology, increasing its engineering practicality.

[0018] (2) The present invention uses the lumped resistor in the matching circuit to absorb waves, avoiding the use of large-volume absorbing materials. Moreover, each unit only needs to load two lumped resistors, which greatly reduces the number of absorbing resistors compared with the existing structure that uses resistors to absorb waves.

[0019] (3) The absorber designed in this invention adopts a circuit structure, which is convenient for integration with other parts in the communication system.

[0020] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0021] Figure 1 This is a structural diagram of a wideband, wide-angle absorber with a planar multilayer PCB structure.

[0022] Figure 2 This is a structural diagram of the metal radiating plate and the metal dielectric plate in the dual-polarized tightly coupled oscillator of Example 1.

[0023] Figure 3 This is a diagram of the support layer structure in the dual-polarized tightly coupled oscillator in Example 1.

[0024] Figure 4 This is a structural diagram of the shared ground plane of the dual-polarized tightly coupled oscillator and the matching circuit in Example 1.

[0025] Figure 5 This is a structural diagram of the matching circuit with a lumped resistor in Example 1.

[0026] Figure 6 This is a schematic diagram showing the reflection coefficient and absorptivity of the planar multilayer PCB structure broadband wide-angle absorber in Example 1 under different incident angles of TE-polarized incident waves.

[0027] Figure 7 This is a schematic diagram showing the simulation results of the reflection coefficient and absorptivity of the planar multilayer PCB structure broadband wide-angle absorber in Example 1 under different incident angles of TM polarized incident waves. Detailed Implementation

[0028] Combination Figure 1A wideband wide-angle absorber with a planar multilayer PCB structure, the absorber includes a dual-polarized tightly coupled oscillator and a matching circuit with a loaded lumped resistor disposed on the back of the oscillator ground plane;

[0029] The dual-polarized tightly coupled oscillator is used to receive electromagnetic waves incident on the surface of the absorber and transmit them to the matching circuit on the back of the floor.

[0030] The matching circuit is used to transmit electromagnetic wave signals to the lumped resistor without loss.

[0031] The lumped resistance is used to absorb electromagnetic waves.

[0032] The design concept of this invention is as follows: First, a dual-polarized tightly coupled dipole antenna is selected, which can receive incident waves of either x-polarization or y-polarization. Then, a matching circuit is loaded on the back of each of the two polarization feed ports of the dipole antenna. The ends of the matching circuits are connected to the dipole antenna ground plane through a lumped resistor. The matching circuits are all loaded on the back of the dipole antenna ground plane, isolating them from the antenna. Finally, the electromagnetic wave energy that can be received by the dipole antenna is absorbed by the lumped resistor, achieving the wave absorption function.

[0033] Specifically, such as Figure 1 As shown, a wideband, wide-angle absorber with a planar multilayer PCB structure includes a dual-polarized tightly coupled vibrator and a matching circuit with a lumped resistor mounted on the back of the vibrator ground plane. The dual-polarized antenna array includes several antenna elements, each comprising a wide-angle matching layer 1, a metal vibrator dielectric substrate 2, a support layer 3, and a common ground plane 9 arranged sequentially. A horizontal metal vibrator radiating plate 5 and a vertical metal vibrator radiating plate 6 are disposed between the wide-angle matching layer 1 and the metal vibrator dielectric substrate 2; each of the horizontal and vertical metal vibrator radiating plates 5 and 6 consists of two vibrator arms, one arm serving as the feed terminal and the other arm grounded. Figure 2 As shown. The support layer 3 is a non-centrally symmetrical cross-shaped structure, as... Figure 3 As shown. A coupling metal disc 7 is disposed above the cross-shaped position of the support layer 3; the center of the coupling metal disc 7 is connected to the common floor 9 through a vertical through hole 8; the horizontal metal radiator 5 and the vertical metal radiator 6 are connected to the common floor 9 through a first vertical short-circuit through hole 10 and a second vertical short-circuit through hole 11, respectively; the horizontal metal radiator 5 and the vertical metal radiator 6 are connected to the first matching circuit 14 and the second matching circuit 15 through the common floor 9 through a first vertical signal through hole 12 and a second vertical signal through hole 13, respectively; the terminals of the first matching circuit 14 and the second matching circuit 15 are respectively loaded with a first lumped resistor 16 and a second lumped resistor 17; the first lumped resistor 16 and the second lumped resistor 17 are respectively connected to the common floor 9 through a first grounding through hole 18 and a second grounding through hole 19, respectively.

[0034] Specifically, a lumped resistor is loaded at the end of the matching circuit, and the lumped resistor is connected to the common floor through a grounding via.

[0035] The matching circuits are all 50-ohm microstrip lines with a lumped resistor of 50 ohms.

[0036] Example 1

[0037] This embodiment describes a wideband, wide-angle absorber with a planar multilayer PCB structure. This absorber can absorb incident waves of arbitrary polarization. The operating frequency band of the absorber in this embodiment is 6-18 GHz, with a relative bandwidth of 100%. Furthermore, this absorber has a low profile and good stability at the oblique incident angle.

[0038] See Figure 1 A broadband, wide-angle absorber with a planar multilayer PCB structure includes a dual-polarized tightly coupled vibrator and a matching circuit with a lumped resistor mounted on the back of the vibrator's ground plane. The dual-polarized tightly coupled vibrator transmits received electromagnetic waves to the matching circuit, where they are absorbed by the lumped resistor at the end of the matching circuit. The dual-polarized antenna element includes a wide-angle matching layer 1, a metal vibrator dielectric substrate 2, a support layer 3, horizontal and vertical metal vibrator radiating plates 5 and 6, a coupling metal disc 7, a vertical via 8, a common ground plane 9, two vertical short-circuit vias 10 and 11, and two vertical signal vias 12 and 16. The wide-angle matching layer 1 is 7.58mm long and wide, made of Teflon, and 2.7mm thick. The dielectric substrate 2 of the metal vibrator is made of Rogers RT5880 and 0.254mm thick. The support layer 3 is made of Teflon and 2.7mm thick. The common ground plane 8 is the copper-clad metal on the back of the band-stop filter, serving as the ground plane for both the dual-polarized antenna array and the band-stop filter. The dielectric substrate 4 of the band-stop filter is made of Rogers RO3003 and 0.254mm thick. To achieve good matching with the metal vibrator radiating plates 5 and 6, four dielectric blocks with dimensions of 0.85mm*0.85mm, 0.85mm*4.53mm, 4.53mm*0.85mm, and 4.53mm*4.53mm, and a thickness of 2.7mm, were removed from the upper left, upper right, lower left, and lower right corners of the support layer 3, respectively. The horizontal and vertical metal vibrator radiating plates 5 and 6 are shaped as follows... Figure 3 As shown. The diameter of the coupling metal disc 7 is 1.88 mm. The diameter of the vertical through-hole 8 is 0.4 mm. The diameters of the two vertical short-circuit through-holes 10 and 11 and the two vertical signal through-holes 12 and 16 are all 0.5 mm. The dimensions of each part of the metal oscillator radiating plate are as follows: p = 7.58, l d1 = 1.4, l d2 = 0.88, l d3= 0.8, l d4 , l d5 = 0.1, l d6 = 0.85 l d7 = 4.53, w d1 =2, w d2 = 1.24, w d3 = 0.68, r f = r g1 = 0.25, r g2 = 0.15, r g3 = 0.25, r g4 = 0.5, l d8 =4.84, l d9 = 1.45, r f = 0.25, w m = 0.7 (unit: mm).

[0039] See Figure 5 This is a schematic diagram of a matching circuit with a lumped resistor in a broadband, wide-angle absorber with a planar multilayer PCB structure. Matching circuit 14 is connected to the vertical metal radiator 6 via vertical signal via 12, and matching circuit 15 is connected to the horizontal metal radiator 5 via vertical signal via 13. The dielectric substrate material of the matching circuit is Rogers RO3003 with a thickness of 0.254 mm. The transmission line width w in the matching circuit... m =0.7 mm, the lumped resistance is 50 ohms, and the radius of the grounding via is r3=0.2 mm.

[0040] See Figure 6 Let be the reflection coefficient and absorptivity of the absorber at different oblique incidence angles, where the incident wave is a linearly polarized wave with TE polarization. The absorptivity is defined as A = 1 – |S 11 | 2 As shown in the figure, under vertical incidence, the reflection coefficient values ​​are all below -10 dB and the absorptivity is above 90% in the 6-19 GHz range. As the oblique incidence angle increases, the absorptivity decreases, but it remains above 80% in the 6-18 GHz range until the incidence angle reaches 50°.

[0041] See Figure 7 The figure shows the reflection coefficient and absorptivity of the absorber at different oblique incidence angles, where the incident wave is a linearly polarized wave with TM polarization. As can be seen from the figure, the absorptivity is above 90% in the 6-19 GHz frequency range with a relative bandwidth of 104% when the incident wave is perpendicular. When the oblique incidence angle increases to 50°, its high-frequency operating bandwidth decreases, but the absorptivity still exceeds 80% in the 6-18 GHz range.

[0042] The absorber designed in this invention features ultra-wideband, low profile, and polarization independence characteristics, along with stable angular characteristics. Furthermore, the absorber can be fabricated using planar PCB technology, increasing its engineering practicality. This invention has important applications in areas such as radar cross-section (RCS) reduction.

[0043] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A broadband wide-angle wave absorber of a planar multilayer PCB structure, characterized by, The wideband, wide-angle absorber includes a dual-polarized tightly coupled oscillator and a matching circuit with a lumped resistor mounted on the back of the oscillator's ground plane; The dual-polarized tightly coupled oscillator is used to receive electromagnetic waves incident on the surface of the absorber and transmit them to the matching circuit on the back of the floor. The matching circuit is used to transmit electromagnetic wave signals to the lumped resistor without loss. The lumped resistance is used to absorb electromagnetic waves; The dual-polarized tightly coupled vibrator includes several antenna elements, each antenna element comprising, from top to bottom, a wide-angle matching layer (1), a metal vibrator dielectric substrate (2), a support layer (3), and a common ground plane (9); a horizontal metal vibrator radiating plate (5) and a vertical metal vibrator radiating plate (6) located on the same horizontal plane are disposed between the wide-angle matching layer (1) and the metal vibrator dielectric substrate (2), and a coupling metal disc (7) is disposed between the metal vibrator dielectric substrate (2) and the support layer (3); the coupling metal disc (7) is connected to the common ground plane (9) through a vertical through hole (8); the horizontal metal vibrator radiating plate (5) and the vertical metal vibrator radiating plate (6) are respectively connected through a first vertical The short-circuit via (10) and the second vertical short-circuit via (11) are connected to the common floor (9); the horizontal metal radiator (5) and the vertical metal radiator (6) are respectively connected to the first matching circuit (14) and the second matching circuit (15) through the common floor (9) via the first vertical signal via (12) and the second vertical signal via (13), respectively. The terminals of the first matching circuit (14) and the second matching circuit (15) are respectively loaded with the first lumped resistor (16) and the second lumped resistor (17). The first lumped resistor (16) and the second lumped resistor (17) are respectively connected to the common floor (9) via the first grounding via (18) and the second grounding via (19), respectively. The metal oscillator dielectric plate (2) and the support layer (3) are non-centrally symmetrical cross-shaped structures; The horizontal metal oscillator radiating plate (5) and the vertical metal oscillator radiating plate (6) are located on the two arms of the cross structure of the metal oscillator dielectric plate (2), thereby forming a non-centrally symmetrical cross structure.

2. The broadband wide-angle absorber with a planar multilayer PCB structure according to claim 1, characterized in that, The horizontal metal oscillator radiator (5) and the vertical metal oscillator radiator (6) each include two oscillator arms, one of which is the feed end and the other is grounded.

3. The broadband wide-angle absorber with a planar multilayer PCB structure according to claim 1, characterized in that, The coupling metal disc (7) is disposed at the intersection of the cross structure.

4. The broadband wide-angle absorber with a planar multilayer PCB structure according to claim 3, characterized in that, The center of the coupling metal disc (7) is connected to the common floor (9) through a vertical through hole (8); the grounded oscillator arms of the horizontal metal oscillator radiator (5) and the vertical metal oscillator radiator (6) are connected to the common floor (9) through a first vertical short-circuit through hole (10) and a second vertical short-circuit through hole (11), respectively.

5. The broadband wide-angle absorber with a planar multilayer PCB structure according to claim 1, characterized in that, Both the first matching circuit (14) and the second matching circuit (15) are 50-ohm microstrip lines.

6. The broadband wide-angle absorber with a planar multilayer PCB structure according to claim 1, characterized in that, The resistance values ​​of the first lumped resistor (16) and the second lumped resistor (17) are 50 ohms.

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