Low-RCS circularly polarized microstrip antenna based on microstrip line coupled feeding

Abstract

The utility model relates to the technical field of microstrip antennas, in particular to a low-RCS (radar cross section) circularly polarized microstrip antenna based on microstrip line coupled feeding, which comprises a first dielectric layer, a second dielectric layer and a third dielectric layer, the second dielectric layer is arranged at the bottom of the first dielectric layer; the number of the micro-strip feeder lines is at least two, and each micro-strip feeder line is arranged between the first dielectric layer and the second dielectric layer; and the second dielectric layer is provided with through allocation through holes corresponding to the micro-strip feeder lines. According to the utility model, a microstrip line coupling feed technology and a miniaturization technology are adopted, so that the antenna has the characteristics of simple structure, easy frequency modulation and the like, good radiation performance is ensured, RCS in an antenna frequency band can be effectively reduced, and the problem that microstrip antennas in related technologies cannot meet the requirements of good radiation performance and low RCS value at the same time is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of microstrip antennas, in particular to a low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding. Background Art

[0002] At present, microstrip antennas have been widely used in various carriers, such as airborne platforms. Airborne platforms usually have high requirements for stealth effects. However, microstrip antennas have a high radar cross-section (RCS value) within the frequency band, which reduces the stealth effect of the corresponding carrier. Therefore, it is particularly important to reduce the RCS value within the frequency band.

[0003] The commonly used methods to reduce the radar cross section (RCS value of microstrip antennas include shape technology, resistive and capacitive diode loading technology, and improved antenna substrate and covering layer technology. The above methods will reduce the radiation performance of the antenna and are not advisable. The slot-coupled microstrip antenna has a certain effect on reducing the radar cross section (RCS value) in the working frequency band, but the slot length of the slot-coupled antenna is the main determinant of the antenna frequency. After the antenna is assembled, errors such as materials and actual processing will cause the antenna frequency to deviate from the required frequency point. When the antenna resonant frequency needs to be adjusted, it will be encountered that it is impossible to adjust the resonant frequency by changing the size of the antenna radiation surface like the coaxial probe-fed microstrip antenna. The resonant frequency can only be changed by adjusting the coupling slot length, which is very difficult to adjust.

[0004] The microstrip antenna provided in the related art cannot simultaneously meet the problem of having good radiation performance and a low RCS value, and no effective solution has been proposed yet. Utility Model Content

[0005] The utility model provides a low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding, which solves the problem that the microstrip antenna in the related art cannot simultaneously meet the requirements of having good radiation performance and low RCS value.

[0006] In order to achieve the above-mentioned purpose, the utility model provides the following technical solutions: a low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding, comprising: a first dielectric layer, a microstrip patch is provided on the top of the first dielectric layer; a second dielectric layer, the second dielectric layer is arranged at the bottom of the first dielectric layer; a microstrip feed line, the microstrip feed lines are at least two, and each of the microstrip feed lines is arranged between the first dielectric layer and the second dielectric layer; the second dielectric layer is respectively provided with penetrating adjustment through holes corresponding to each of the microstrip feed lines.

[0007] Preferably, the dielectric constant of the first dielectric layer is 7 to 25.

[0008] Preferably, the dielectric constant of the second dielectric layer is 2 to 10.

[0009] Preferably, the microstrip patch is an irregularly shaped patch.

[0010] Preferably, it further includes an intermediate metal layer, wherein the intermediate metal layer is connected between the first dielectric layer and the second dielectric layer.

[0011] Preferably, the intermediate metal layer is in a metal frame structure and is arranged along an edge of the first dielectric layer; the edge of the intermediate metal layer is spaced apart from an edge of the microstrip feeder line.

[0012] Preferably, it also includes a 3dB feeding network, which is arranged at the bottom of the second dielectric layer to achieve an output with an equal amplitude phase difference of 90°; a network feeding probe that passes through the second dielectric layer is provided at the top of the 3dB feeding network corresponding to each of the microstrip feed lines, and each of the network feeding probes is respectively connected to the outer edge of the corresponding microstrip feed line; an output connector is provided at the bottom of the 3dB feeding network.

[0013] Preferably, a plurality of welding holes are provided at the edge of the second dielectric layer, and the first dielectric layer, the second dielectric layer and the 3dB feeding network are fixedly connected through the welding holes.

[0014] Preferably, the dielectric constant of the first dielectric layer is 16, and the size is 35mm*35mm*5.01mm; the dielectric constant of the second dielectric layer is 10, and the size is 35mm*35mm*1.02mm; the size of the adjustment through hole is 3mm*2mm; the operating center frequency of the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding is 1.268GHz.

[0015] The beneficial effects of the utility model are as follows: the microstrip line coupling feeding technology and miniaturization technology are adopted, so that the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding has the characteristics of simple structure and easy frequency modulation, while ensuring good radiation performance, it can also effectively reduce the RCS within the antenna band, solving the problem that the microstrip antenna in the related technology cannot meet the requirements of having good radiation performance and low RCS value at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in 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 only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0018] Figure 2 It is a schematic diagram of a microstrip patch of the utility model;

[0019] Figure 3 This is a graph showing the frequency of the present utility model changing with the size of the microstrip patch;

[0020] Figure 4 This is a simulation result diagram of the gain pattern of the utility model;

[0021] Figure 5 This is a simulation result diagram of the axial ratio direction diagram of the utility model;

[0022] Figure 6 This is a diagram of the RCS simulation results of a single station when the incident wave direction is Phi=0° and Theta=0°;

[0023] Figure 7 This is a diagram of dual-station RCS simulation results when the center frequency is 1.268 GHz for the utility model.

[0024] In the figure: 1. Microstrip patch; 2. First dielectric layer; 3. Microstrip feed line; 4. Second dielectric layer; 5. Adjustment through hole; 6. Intermediate metal layer; 7. 3dB feeding network; 8. Network feeding probe; 9. Output connector; 10. Welding hole. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings of the utility model to clearly and completely describe the technical solution of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] according to Figure 1 , Figure 2 As shown, a low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding includes: a first dielectric layer 2, a microstrip patch 1 is provided on the top of the first dielectric layer 2; a second dielectric layer 4, the second dielectric layer 4 is arranged at the bottom of the first dielectric layer 2; microstrip feed lines 3, there are at least two microstrip feed lines 3, and each of the microstrip feed lines 3 is arranged between the first dielectric layer 2 and the second dielectric layer 4; the second dielectric layer 4 is respectively provided with penetrating adjustment through holes 5 corresponding to each of the microstrip feed lines 3.

[0027] The above structure adopts microstrip line coupling feeding, so that the microstrip feed line and the patch are located in different dielectric layers, thereby reducing the influence of the microstrip feed line on the patch scattering, and reducing the radar cross section (RCS) value of the antenna. In addition, since each adjustment through hole 5 in the structure is arranged under at least two microstrip feed lines 3 in a one-to-one correspondence, the antenna obtains good impedance matching characteristics and can have good radiation performance.

[0028] It should be noted that the embodiment is described by taking two microstrip feed lines 3 as an example, but the solution of the present utility model is not limited thereto, and may also include a technical solution of four microstrip feed lines 3 .

[0029] As a preferred embodiment, the dielectric constant of the first dielectric layer 2 can be 7 to 25. When the dielectric constant is within this range, the size of the antenna can be reduced, which has the advantage of miniaturization of the antenna and also has the effect of reducing the RCS value.

[0030] As a preferred embodiment, the dielectric constant of the second dielectric layer 4 is 2 to 10. When the dielectric constant is within this range, the size of the antenna can be reduced, which has the advantage of miniaturization of the antenna and also has the effect of reducing the RCS value.

[0031] As a preferred implementation method, Figure 2 As shown, the microstrip patch 1 is an irregular shaped patch with chamfered corners and right-angled edges transitioned into arcs. By specially processing the microstrip patch 1, the scattering characteristics of the patch are changed, which has a beneficial effect on the low radar cross section (RCS) characteristics of the antenna.

[0032] It also includes an intermediate metal layer 6, which is connected between the first dielectric layer 2 and the second dielectric layer 4. The intermediate metal layer 6 is a metal frame structure and is arranged along the edge of the first dielectric layer 2; the edge of the intermediate metal layer 6 is spaced apart from the edge of the microstrip feeder 3. It also includes a 3dB feeding network 7, which is arranged at the bottom of the second dielectric layer 4 to achieve an output with a constant amplitude phase difference of 90°; a network feeding probe 8 penetrating the second dielectric layer 4 is provided at the top of the 3dB feeding network 7 corresponding to each of the microstrip feeders 3, and each of the network feeding probes 8 is respectively connected to the outer edge of the corresponding microstrip feeder 3; an output connector 9 is provided at the bottom of the 3dB feeding network 7. A plurality of welding holes 10 are provided at the edge of the second dielectric layer 4, and the first dielectric layer 2, the second dielectric layer 4 and the 3dB feeding network 7 are fixedly connected through the welding holes 10.

[0033] As a preferred embodiment, the dielectric constant of the first dielectric layer 2 is 16, and the size is 35mm*35mm*5.01mm; the dielectric constant of the second dielectric layer 4 is 10, and the size is 35mm*35mm*1.02mm; the size of the adjustment through hole 5 is 3mm*2mm; the operating center frequency of the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding is 1.268GHz. Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 All of them are simulation results obtained based on the parameter settings of this embodiment.

[0034] Figure 3 1 is a graph showing the frequency variation of a low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding according to an embodiment of the present utility model with respect to the size of a microstrip patch 1, as shown in FIG. Figure 3 As shown, when the size L of the microstrip patch 1 of the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding changes, its resonant frequency also changes accordingly, so that it is easier to debug the resonant frequency of the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding by changing the size of the microstrip patch 1 in the later stage.

[0035] Figure 4 : is a simulation result diagram of the gain pattern of the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding according to an embodiment of the utility model, such as Figure 4 As shown in Figure 2, the gain pattern simulation results of the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding are as follows: Figure 4 The medium-coupled antenna curve is better than the gain pattern simulation result of the conventional microstrip antenna as the reference antenna. The axial gain at 0 degrees is 5dB, and the gain at an elevation angle of 80 degrees is -1.56dB, indicating that the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding has good radiation characteristics.

[0036] Figure 5 : is a simulation result diagram of the axial ratio pattern of the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding according to an embodiment of the utility model, such as Figure 5 As shown in Figure 2, the axial ratio pattern simulation results of the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding are as follows: Figure 5 The medium-coupled antenna curve is better than the axial ratio radiation pattern simulation result of the conventional microstrip antenna as the reference antenna. The axial ratio at 0 degrees is 0.23dB, and the axial ratio at an elevation angle of 80 degrees is 3.5dB, indicating that the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding has good axial ratio characteristics.

[0037] Figure 6This is the single-station RCS simulation result diagram of the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding when the incident wave direction is Ph i=0°, Theta=0°, as shown in Figure 6 As shown in Figure 2, the single-station RCS simulation results of the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding are: Figure 6 The medium-coupled antenna curve shows that the radar cross section (RCS) is reduced by 20 dB compared with the single-station RCS simulation result using the conventional microstrip antenna as the reference antenna, indicating that the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding has a smaller single-station radar cross section (RCS) value.

[0038] Figure 7 This is a diagram of the dual-station RCS simulation result when the center frequency of the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding according to an embodiment of the utility model is 1.268 GHz, as shown in FIG. Figure 7 As shown in the figure, the bistatic RCS simulation results of the low RCS circularly polarized microstrip antenna based on microstrip line coupling feed at 1.268GHz are as follows: Figure 7 The medium-coupled antenna curve shows that compared with the bistatic RCS simulation result of using the conventional microstrip antenna as the reference antenna, the radar cross section (RCS) reduction is as small as 17dB and as large as 30dB, indicating that the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding has a smaller bistatic radar cross section (RCS) value.

[0039] In summary, the microstrip line coupling feeding technology and miniaturization technology are adopted to make it have the characteristics of simple structure and easy frequency modulation. While ensuring good radiation performance, it can also effectively reduce the RCS within the antenna frequency band, solving the problem that the microstrip antenna in the related technology cannot meet the requirements of good radiation performance and low RCS value at the same time.

[0040] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding, characterized in that ,include: A first dielectric layer (2), wherein a microstrip patch (1) is provided on the top of the first dielectric layer (2); A second dielectric layer (4), the second dielectric layer (4) being arranged at the bottom of the first dielectric layer (2); Microstrip feed lines (3), there are at least two microstrip feed lines (3), and each of the microstrip feed lines (3) is arranged between the first dielectric layer (2) and the second dielectric layer (4); The second dielectric layer (4) is provided with penetrating adjustment through holes (5) corresponding to each of the microstrip feed lines (3).

2. A low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding according to claim 1, characterized in that: The dielectric constant of the first dielectric layer (2) is 7 to 25.

3. The low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding according to claim 1, characterized in that: The dielectric constant of the second dielectric layer (4) is 2 to 10.

4. The low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding according to claim 1, characterized in that: The microstrip patch (1) is a patch with chamfered corners and right-angled edges in arc transition.

5. The low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding according to claim 1, characterized in that: It also comprises an intermediate metal layer (6), wherein the intermediate metal layer (6) is connected between the first dielectric layer (2) and the second dielectric layer (4).

6. A low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding according to claim 5, characterized in that: The intermediate metal layer (6) is in a metal frame structure and is arranged along the edge of the first dielectric layer (2); the edge of the intermediate metal layer (6) is spaced apart from the edge of the microstrip feed line (3).

7. A low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding according to claim 6, characterized in that: It also includes a 3dB feeding network (7), which is arranged at the bottom of the second dielectric layer (4) and is used to achieve an output with a constant amplitude phase difference of 90°; A network feeding probe (8) penetrating the second dielectric layer (4) is provided at the top of the 3dB feeding network (7) corresponding to each of the microstrip feed lines (3), and each of the network feeding probes (8) is respectively connected to the outer edge of the corresponding microstrip feed line (3); An output connector (9) is provided at the bottom of the 3dB feeding network (7).

8. The low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding according to claim 7, characterized in that: A plurality of welding holes (10) are provided at the edge of the second dielectric layer (4), and the first dielectric layer (2), the second dielectric layer (4) and the 3dB feeding network (7) are fixedly connected via the welding holes (10).

9. The low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding according to claim 1, characterized in that: The dielectric constant of the first dielectric layer (2) is 16, and the size is 35mm*35mm*5.01mm; the dielectric constant of the second dielectric layer (4) is 10, and the size is 35mm*35mm*1.02mm; the size of the adjustment through hole (5) is 3mm*2mm; and the operating center frequency of the low RCS circularly polarized microstrip antenna based on microstrip line coupling feeding is 1.268GHz.

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