Circularly polarized antenna based on multi-mode frequency selective surface, integration method and terminal

Abstract

The invention relates to the technical field of wireless communication and antenna design, and discloses a circularly polarized antenna based on a multi-mode frequency selective surface, an integration method and a terminal. A wave absorbing layer, a first diffuse reflection layer and a second diffuse reflection layer are sequentially integrated on the circularly polarized antenna body from top to bottom. Wherein the circularly polarized antenna body has a working frequency band, the wave absorbing layer has a wave absorbing frequency band, the first diffuse reflection layer has a first diffuse reflection frequency band, and the second diffuse reflection layer has a second diffuse reflection frequency band; the working frequency band, the wave absorbing frequency band, the first diffuse reflection frequency band and the second diffuse reflection frequency band are efficiently integrated, the requirements for high-flexibility radiation and strong electromagnetic stealth are met, and the design of the multi-mode radiation stealth integrated array antenna is achieved. According to the invention, the out-of-band radar cross section (RCS) can be efficiently suppressed while the radiation efficiency in the working band of the antenna is not influenced, and the fusion target of high-performance radiation and ultra-wideband RCS suppression stealth is fundamentally completed.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless communication and antenna design, and in particular to a circularly polarized antenna based on a multi-mode frequency selective surface, an integration method and a terminal. Background Art

[0002] The development of modern electromagnetic environment has put forward more stringent electromagnetic stealth protection requirements for high-speed penetration equipment. How to improve the battlefield survivability of penetration equipment is an urgent problem to be solved. In these equipment, antennas often bring strong radar echo scattering due to their necessary outward radiation function, thereby increasing the probability of the equipment being detected.

[0003] Multimodal stealth electromagnetic surfaces can flexibly manipulate the amplitude, phase, and polarization characteristics of incident electromagnetic waves, and are therefore widely used to suppress antenna radar cross sections (RCS). Electromagnetic surfaces can flexibly regulate the amplitude and phase characteristics of incident electromagnetic waves according to the frequency, thereby realizing functions such as bandpass / bandstop electromagnetic surfaces with transmission / reflection performance, absorbing electromagnetic surfaces with amplitude suppression functions, and polarization conversion electromagnetic surfaces with phase control functions. However, these electromagnetic surfaces can generally only achieve a single function and are difficult to cope with modern complex electromagnetic environments. While using stealth electromagnetic surfaces to reduce the antenna RCS, it is necessary to ensure that the radiation performance of the antenna is not affected, which is the difficulty in designing stealth electromagnetic surfaces.

[0004] In view of this, it is urgent to propose an antenna that can suppress the out-of-band RCS without affecting the radiation efficiency in the antenna working band and has a good stealth effect. Summary of the invention

[0005] The object of the present invention is to provide a circularly polarized antenna, an integration method and a terminal based on a multi-modal frequency selective surface. The circularly polarized antenna embeds the absorption, transmission and diffusion modes into the multi-modal frequency selective surface, can realize independent regulation of each mode, can suppress the out-of-band RCS without affecting the radiation efficiency in the antenna working band, and has a good stealth effect.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] In a first aspect, the present invention provides a circularly polarized antenna based on a multi-mode frequency selective surface, on which an absorbing layer, a first diffuse reflection layer and a second diffuse reflection layer are integrated in sequence from top to bottom on a circularly polarized antenna body; wherein the circularly polarized antenna body has an operating frequency band, the absorbing layer has an absorbing frequency band, the first diffuse reflection layer has a first diffuse reflection frequency band, and the second diffuse reflection layer has a second diffuse reflection frequency band; the operating frequency band neither crosses nor overlaps with the absorbing frequency band, the first diffuse reflection frequency band, and the second diffuse reflection frequency band.

[0008] As a possible implementation, the absorbing layer includes a dielectric substrate, the dielectric substrate includes a first surface and a second surface opposite to each other, a first metal strip is formed on the first surface, a second metal strip is formed on the second surface, the first metal strip and the second metal strip are perpendicular but do not intersect; chip resistors are arranged at the vertical points of the first metal strip and the second metal strip.

[0009] As a possible implementation, the dielectric substrate is a rectangular dielectric substrate, the first metal strip is a first bent metal strip formed on a first diagonal line of the rectangular dielectric substrate, and the second metal strip is a second bent metal strip formed on a second diagonal line of the rectangular dielectric substrate.

[0010] As a possible implementation, the first diffuse reflection layer has a first surface and a second surface opposite to each other, the first surface is opposite to the wave absorbing layer; the first surface is divided into a plurality of first diffuse reflection areas; each first diffuse reflection area is provided with first diffuse reflection metal strips arranged in a regular matrix; the first diffuse reflection metal strips located in the same first diffuse reflection area have the same inclination direction; the first diffuse reflection metal strips in adjacent first diffuse reflection areas are symmetrically arranged with adjacent sides as symmetry axes;

[0011] The second diffuse reflection layer has a first surface and a second surface opposite to each other, the first surface is opposite to the first diffuse reflection layer; the first surface is divided into a plurality of second diffuse reflection areas, the number and area of ​​the second diffuse reflection areas are the same as those of the first diffuse reflection areas, and one first diffuse reflection area corresponds to one second diffuse reflection area in space; second diffuse reflection metal strips arranged in a regular matrix are arranged in each second diffuse reflection area, and the inclination direction of the second diffuse reflection metal strips is perpendicular to the inclination direction of the first diffuse reflection metal strips in the corresponding first diffuse reflection area.

[0012] As a possible implementation manner, a repetition period of the second diffuse reflection metal strips in the second diffuse reflection region is twice a repetition period of the first diffuse reflection metal strips in the corresponding first diffuse reflection region.

[0013] As a possible implementation manner, the first diffuse reflection metal strip and the second diffuse reflection metal strip are both straight line structures with arrows at both ends.

[0014] As a possible implementation manner, the circularly polarized antenna body is a circularly polarized antenna body configured with a 90° one-to-two power divider and a one-to-four feeding network.

[0015] As a possible implementation, the circularly polarized antenna body includes a parasitic patch layer, a driving patch layer, a first metal ground, a 90° one-to-two power divider, a second metal ground, and a one-to-four feeding network in sequence from the direction close to the second diffuse reflection layer to the direction away from the second diffuse reflection layer;

[0016] The parasitic patch layer is coupled with the driving patch layer and then connected to a 90° one-to-two power divider, and the 90° one-to-two power divider is fed by a one-to-four feeding network.

[0017] In a second aspect, the present invention provides an integration method for manufacturing the circularly polarized antenna based on the multi-mode frequency selective surface provided in the first aspect, the integration method comprising the following steps:

[0018] A circularly polarized antenna body is provided, which includes, from top to bottom, a parasitic patch layer, a driving patch layer, a first metal ground, a 90° one-to-two power divider, a second metal ground, and a one-to-four feeding network;

[0019] An absorption layer is manufactured, and a dielectric substrate is provided, wherein the dielectric substrate comprises a first surface and a second surface opposite to each other, a first metal strip is etched on the first surface, and a second metal strip is etched on the second surface; the first metal strip and the second metal strip are perpendicular to each other but do not intersect, and chip resistors are arranged at the perpendicular points of the first metal strip and the second metal strip;

[0020] A first diffuse reflection layer is manufactured by providing a dielectric substrate, wherein the dielectric substrate has a first surface and a second surface opposite to each other, and the first surface is opposite to the wave absorbing layer; a plurality of first diffuse reflection regions are formed by dividing the first surface; first diffuse reflection metal strips arranged in a regular matrix are etched in each first diffuse reflection region; the first diffuse reflection metal strips in the same first diffuse reflection region have the same inclination direction; and the first diffuse reflection metal strips in adjacent first diffuse reflection regions are symmetrically arranged with adjacent sides as symmetry axes;

[0021] A second diffuse reflection layer is manufactured by providing a dielectric substrate, wherein the dielectric substrate has a first surface and a second surface opposite to each other, the first surface is opposite to the first diffuse reflection layer, and the first surface is divided into a plurality of second diffuse reflection areas, the number of the second diffuse reflection areas is the same as that of the first diffuse reflection areas, and the areas are equal, and one first diffuse reflection area corresponds to one second diffuse reflection area in space; second diffuse reflection metal strips arranged in a regular matrix are arranged in each second diffuse reflection area, and the inclination direction of the second diffuse reflection metal strips is perpendicular to the inclination direction of the first diffuse reflection metal strips in the corresponding first diffuse reflection area;

[0022] The absorption layer, the first diffuse reflection layer and the second diffuse reflection layer are sequentially integrated on the circular polarization antenna body from top to bottom.

[0023] In a third aspect, the present invention further provides a terminal, which uses the circularly polarized antenna based on the multi-mode frequency selective surface provided in the first aspect.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. The circularly polarized antenna based on the multi-modal frequency selective surface provided by the present invention has an absorbing layer that can absorb low-frequency electromagnetic waves in the incident electromagnetic waves, and the absorbing layer has high transmittance to the incident electromagnetic waves in the medium and high frequency bands, so that the incident electromagnetic waves in the medium and high frequency bands can pass through the absorbing layer to reach the first diffuse reflection layer or the second diffuse reflection layer, and the first diffuse reflection layer and the second diffuse reflection layer can diffusely reflect the incident electromagnetic waves in their respective corresponding diffuse reflection frequency bands in different directions, thereby achieving a better stealth effect.

[0026] 2. The circularly polarized antenna based on the multi-modal frequency selective surface provided by the present invention has an operating frequency band that does not cross or overlap with the absorbing frequency band, the first diffuse reflection frequency band, and the second diffuse reflection frequency band, and will not affect the transmission of electromagnetic waves within the working frequency band of the antenna. It can ensure ultra-wideband stealth in the S, C, X, and Ku bands, and will not affect the radiation efficiency within the working band of the antenna.

[0027] 3. The circularly polarized antenna based on the multi-modal frequency selective surface provided by the present invention embeds the absorption, transmission and diffusion modes into the multi-modal frequency selective surface, and can realize independent regulation of each mode.

[0028] 4. The circularly polarized antenna based on the multi-mode frequency selective surface provided by the present invention adopts a combination design of a 90° one-to-two power divider and a one-to-four feeding network, which can obtain a smaller axial ratio, thereby improving the circular polarization performance of the antenna, making the present invention more modular in adjustment and control, and providing more possibilities for applications requiring multi-band, wide bandwidth, low loss, etc.

[0029] 5. The circularly polarized antenna based on the multi-mode frequency selective surface provided by the present invention has outstanding RCS suppression performance under different polarization conditions and at different incident angles. It not only achieves significant RCS reduction within the target operating frequency band, but also can adapt to multi-angle and multi-polarization electromagnetic wave environments, reflecting the versatility of the structure and its wide application potential. It is of great significance in various scenarios such as space detection, radar systems, and multi-band stealth platforms. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0031] Figure 1 and Figure 2 Schematic diagram of the structure of a circularly polarized antenna based on a multi-mode frequency selective surface in an embodiment of the present invention;

[0032] Figure 3A schematic diagram of a configuration method of the first diffuse reflection metal strip in each first diffuse reflection area in an embodiment of the present invention;

[0033] Figure 4 It is a schematic diagram showing that a repetition period of the second diffuse reflection metal strips in the second diffuse reflection area is twice the repetition period of the first diffuse reflection metal strips in the corresponding first diffuse reflection area in an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the structure of the wave absorbing layer in an embodiment of the present invention;

[0035] Figure 6 This is a simulation result diagram of the absorbing layer in an embodiment of the present invention;

[0036] Figure 7 Schematic diagram of the double-layer diffuse reflection layer structure in an embodiment of the present invention;

[0037] Figure 8 This is a simulation result diagram of the diffuse reflection layer in an embodiment of the present invention;

[0038] Fig. 9 This is a schematic diagram of the structure of a circularly polarized antenna body in an embodiment of the present invention;

[0039] Fig.10 The simulation result diagram of the axial ratio and standing wave ratio of the circularly polarized antenna body in the embodiment of the present invention is shown;

[0040] Fig.11 Graph showing simulation results of axial ratio and standing wave ratio of circularly polarized antenna based on multi-mode frequency selective surface in an embodiment of the present invention;

[0041] Fig.12 This is a simulation result diagram of circularly polarized antenna gain based on a multi-mode frequency selective surface in an embodiment of the present invention;

[0042] Fig.13 An exploded diagram of an 8×8 array structure of circularly polarized antennas based on a multi-mode frequency selective surface in an embodiment of the present invention;

[0043] Fig.14 This is a simulation result diagram of the axial ratio and standing wave ratio of the circularly polarized antenna 8×8 array structure based on the multi-mode frequency selective surface in an embodiment of the present invention;

[0044] Fig.15 This is a diagram showing the gain simulation results of a circularly polarized antenna 8×8 array structure based on a multi-mode frequency selective surface in an embodiment of the present invention;

[0045] Fig.16 This is a diagram of RCS reduction simulation results of a circularly polarized antenna 8×8 array structure based on a multi-mode frequency selective surface under TE polarization in an embodiment of the present invention;

[0046] Fig.17This is a diagram of the RCS reduction simulation results of the 8×8 circularly polarized antenna array structure based on the multi-mode frequency selective surface under TM polarization in an embodiment of the present invention.

[0047] Reference numerals

[0048] 1-wave absorbing layer, 10-dielectric substrate, 100-first metal strip, 101-second metal strip, 102-chip resistor, 2-first diffuse reflection layer, 20-first diffuse reflection metal strip, 3-second diffuse reflection layer, 30-second diffuse reflection metal strip, 4-circularly polarized antenna body, 40-90° one-to-two power divider, 41-one-to-four feeding network, 42-parasitic patch layer, 43-driving patch layer, 44-first metal ground, 45-second metal ground, 5-metal floor. DETAILED DESCRIPTION

[0049] In order to clearly describe the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, words such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and effects. For example, the first threshold and the second threshold are only used to distinguish different thresholds, and their order is not limited. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different.

[0050] It should be noted that, in the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0051] In the present invention, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. The following at least one item (items) or similar expressions thereof refer to any combination of these items, including any combination of single items (items) or plural items (items). For example, at least one item (items) of a, b or c can mean: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b, c can be single or multiple.

[0052] The embodiments of the present invention provide a circularly polarized antenna, an integration method and a terminal based on a multi-modal frequency selective surface. The circularly polarized antenna embeds the absorption, transmission and diffusion modes into the multi-modal frequency selective surface, can realize independent regulation of each mode, can suppress the out-of-band RCS without affecting the radiation efficiency within the antenna working band, and has a good stealth effect.

[0053] In a first aspect, the present invention provides a circularly polarized antenna based on a multi-mode frequency selective surface, see Figure 1 On the circularly polarized antenna body 4, an absorbing layer 1, a first diffuse reflection layer 2 and a second diffuse reflection layer 3 are integrated in sequence from top to bottom.

[0054] See also Figure 1 As a possible implementation, the wave absorbing layer 1 includes a dielectric substrate 10. The shape of the dielectric substrate 10 is not specifically limited. For example, it can be a square dielectric substrate or a rectangular dielectric substrate. The embodiment of the present invention is described by taking a rectangular dielectric substrate as an example. The dielectric substrate 10 includes a first surface and a second surface opposite to each other. The first surface is formed with a first metal strip 100. The first metal strip 100 is a first curved metal strip formed on the first diagonal of the rectangular dielectric substrate. The second surface is formed with a second metal strip 101. The second metal strip 101 is a second curved metal strip formed on the second diagonal of the rectangular dielectric substrate. The first metal strip 100 and the second metal strip 101 are perpendicular but do not intersect. Chip resistors 102 are arranged at the vertical points of the first metal strip 100 and the second metal strip 101. In this way, the overlap of the two chip resistors 102 can be avoided. Due to the symmetry of the patterns of the two metal strips, the polarization insensitivity of the surface of the wave absorbing layer can also be achieved. In actual application, the first curved metal strip and the second curved metal strip constitute a resonator, and the first diffuse reflection layer 2 can be used as a total reflection metal surface, and together with the absorbing layer, it forms an artificial electromagnetic frequency selective surface. When the incident electromagnetic wave in the low frequency band passes through the absorbing layer, the resonator resonates out of the circuit, and the current passes through the chip resistor 102, so that the energy is converted into heat and dissipated into the air, thereby absorbing the incident electromagnetic wave in the low frequency band.

[0055] The circularly polarized antenna body 4 has a working frequency band, the absorbing layer 1 has a absorbing frequency band, the first diffuse reflection layer 2 has a first diffuse reflection frequency band, and the second diffuse reflection layer 3 has a second diffuse reflection frequency band; the working frequency band does not cross or overlap with the absorbing frequency band, the first diffuse reflection frequency band, and the second diffuse reflection frequency band. Exemplarily, the absorbing frequency band is 2 to 6 GHz, the first diffuse reflection frequency band is 7 to 13 GHz, the second diffuse reflection frequency band is 16 to 22 GHz, and the working frequency band is 14 to 15 GHz. The first diffuse reflection frequency band is lower than the working frequency band, and the second diffuse reflection frequency band is higher than the working frequency band. When the incident electromagnetic wave is within the working frequency band, the absorbing layer 1 has efficient electromagnetic wave transmission characteristics and hardly affects the electromagnetic wave transmission in this frequency band. Therefore, the entire structure of the present invention does not interfere with the electromagnetic waves radiated by the antenna, so that it can be completely transmitted without affecting the radiation performance of the antenna.

[0056] See also Figure 1 to Figure 2 As a possible implementation method, the first diffuse reflection layer 2 has a first surface and a second surface opposite to each other, the first surface is opposite to the absorbing layer 1; the first surface is divided into a plurality of first diffuse reflection areas; each first diffuse reflection area is provided with first diffuse reflection metal strips 20 arranged in a regular matrix; the first diffuse reflection metal strips 20 located in the same first diffuse reflection area have the same inclination direction; the first diffuse reflection metal strips 20 in adjacent first diffuse reflection areas are symmetrically arranged with adjacent sides as symmetry axes.

[0057] See also Figures 1 to 3 As an example, the first surface of the first diffuse reflection layer 2 is divided into four first diffuse reflection areas a1, a2, a3, and a4, and each first diffuse reflection area is provided with first diffuse reflection metal strips 20 arranged in a regular matrix.

[0058] For example, see Figure 3 (1) A first diffuse reflection metal strip 20 is arranged in each first diffuse reflection area, and the first diffuse reflection metal strips 20 in adjacent first diffuse reflection areas are symmetrically arranged with adjacent sides as symmetry axes. For example, the first diffuse reflection metal strips 20 in areas a1 and a2 are symmetrically arranged with adjacent sides L2 as symmetry axes, and the first diffuse reflection metal strips 20 in areas a1 and a3 are symmetrically arranged with adjacent sides L1 as symmetry axes.

[0059] For example, see Figure 3(2) Two first diffuse reflection metal strips 20 are arranged in each first diffuse reflection area. The inclination directions of the two first diffuse reflection metal strips 20 located in the same first diffuse reflection area are consistent, and the first diffuse reflection metal strips 20 in adjacent first diffuse reflection areas are symmetrically arranged with adjacent sides as symmetry axes. For example, the two first diffuse reflection metal strips 20 in areas a1 and a2 are symmetrically arranged with adjacent sides L4 as symmetry axes, and the two first diffuse reflection metal strips 20 in areas a1 and a3 are symmetrically arranged with adjacent sides L3 as symmetry axes.

[0060] See also Figure 1 to Figure 2 As a possible implementation method, the second diffuse reflection layer 3 has a first surface and a second surface opposite to each other, the first surface is opposite to the first diffuse reflection layer 2; the first surface is divided into a plurality of second diffuse reflection areas, the number and area of ​​the second diffuse reflection areas are the same as those of the first diffuse reflection areas, and one first diffuse reflection area corresponds to one second diffuse reflection area in space; each second diffuse reflection area is provided with second diffuse reflection metal strips 30 arranged in a regular matrix, and the inclination direction of the second diffuse reflection metal strips 30 is perpendicular to the inclination direction of the first diffuse reflection metal strips 20 in the corresponding first diffuse reflection area.

[0061] See also Figures 1 to 4 As an example, the first surface of the second diffuse reflection layer 3 is divided into four second diffuse reflection areas b1, b2, b3, and b4, and the areas b1 and a1, b2 and a2, b3 and a3, and b4 and a4 correspond to each other in space and have the same areas; see Figure 4 (2) In each second diffuse reflection region, second diffuse reflection metal strips 30 are arranged in a regular matrix, and the inclination direction of the second diffuse reflection metal strips 30 is the same as that of the second diffuse reflection metal strips 30. Figure 4 The inclination direction of the first diffuse reflection metal strip 20 in the first diffuse reflection area in (1) is vertical.

[0062] See also Figure 4 As a possible implementation, the repetition period of the second diffuse reflection metal strip 30 in the second diffuse reflection area is twice the repetition period of the first diffuse reflection metal strip 20 in the first diffuse reflection area corresponding thereto; that is, if the repetition period of the first diffuse reflection metal strip 20 in the first diffuse reflection area is n×n, then the repetition period of the second diffuse reflection metal strip 30 in the second diffuse reflection area corresponding to the first diffuse reflection area is 2n×2n. For example, see Figure 4 (1) The repetition period of the first diffuse reflection metal strip 20 in the first diffuse reflection area a1 is 1 in both the horizontal and vertical directions, i.e., 1×1. Then, the repetition period of the second diffuse reflection metal strip 30 in the second diffuse reflection area b1 corresponding to the first diffuse reflection area a1 is 2×2, i.e., 4.

[0063] See also Figure 2As a possible implementation, the first diffuse reflection metal strip 20 and the second diffuse reflection metal strip 30 are both straight line structures with arrows at both ends. Exemplarily, the two sides of the arrows are vertical, and the first diffuse reflection metal strip 20 and the second diffuse reflection metal strip 30 can be respectively disposed on the first surfaces of the two diffuse reflection layers by etching, printing, etc.

[0064] The circularly polarized antenna provided by the present invention has an absorbing layer that can absorb low-frequency electromagnetic waves in the incident electromagnetic waves, and the absorbing layer has high transmittance for the incident electromagnetic waves in the medium and high frequency bands, so that the incident electromagnetic waves in the medium and high frequency bands can pass through the absorbing layer to reach the first diffuse reflection layer or the second diffuse reflection layer, and the first diffuse reflection layer and the second diffuse reflection layer can diffusely reflect the incident electromagnetic waves in their respective corresponding diffuse reflection frequency bands in different directions, thereby achieving a better stealth effect. The working frequency band of the circularly polarized antenna body itself neither crosses nor overlaps with the absorbing frequency band, the first diffuse reflection frequency band, and the second diffuse reflection frequency band, that is, it will not affect the transmission of electromagnetic waves in the antenna working frequency band, and will not affect the radiation efficiency in the antenna working band. In the high frequency band, the second diffuse reflection layer exhibits a polarization conversion characteristic to the incident electromagnetic wave, so that the energy of the incident electromagnetic wave is dispersed in all directions, thereby suppressing the back reflection performance, forming a high-frequency diffuse reflection frequency band, and realizing electromagnetic stealth.

[0065] See also Figure 2 As a possible implementation method, the circularly polarized antenna body 4 is a circularly polarized antenna body configured with a 90° one-to-two power divider 40 and a one-to-four feeding network 41. The circularly polarized antenna based on the multi-modal frequency selective surface provided in the present application adjusts the phase difference by changing the line length through a 90° one-to-two power divider to achieve broadband circular polarization. Compared with the prior art that realizes circular polarization by cutting corners on a square patch, the present application is more convenient for adjusting the working frequency band of the antenna, such as the axial ratio and the standing wave ratio, so as to achieve better circular polarization performance. The present application does not require patch cutting corners, has a simple design, and is easier to implement in the processing technology, which greatly reduces the manufacturing cost and process difficulty.

[0066] For example, see Figure 1 to Figure 2 As a possible implementation, the circularly polarized antenna body 4 includes a parasitic patch layer 42, a driving patch layer 43, a first metal ground 44, a 90° one-to-two power divider 40, a second metal ground 45, and a one-to-four feeding network 41 in order from the direction close to the second diffuse reflection layer 3 to the direction away from the second diffuse reflection layer 3. Among them, the parasitic patch layer 42 and the driving patch layer 43 are both squares, but the side lengths of the two squares are different. Preferably, the side length of the driving patch layer 43 is greater than the side length of the parasitic patch layer 42.

[0067] This application sequentially rotates a single 90° one-to-two power splitter to form an array, combines a one-to-four feeding network to feed the circularly polarized antenna body, and together with the absorbing layer and two diffuse reflection layers, forms a modal radiation stealth integrated broadband low RCS circularly polarized antenna unit structure. The combined design of the 90° one-to-two power splitter and the one-to-four feeding network can obtain a smaller axial ratio, thereby improving the circular polarization performance of the antenna, making the present invention more modular in adjustment and control, and providing more possibilities for applications requiring multi-band, wide bandwidth, low loss, etc.

[0068] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0069] See also Figure 5 , is a schematic diagram of the structure of the absorbing layer provided in this embodiment. In order to observe the energy absorption characteristics of the absorbing layer to the incident electromagnetic wave, this embodiment loads a metal floor 5 at a distance h from the absorbing layer 1. In actual design, the metal floor 5 can also be replaced by other structures that can exhibit total reflection characteristics. The absorbing layer 1 and the metal floor 5 are separated by an air cavity with a height of h. According to the quarter-wavelength conversion theory, in order to achieve the optimal energy absorption performance, in this embodiment, h is one-quarter of the wavelength corresponding to the center frequency of the absorption frequency band, that is, h = 18mm. The dielectric substrate 10 of the absorbing layer 1 has a thickness of t = 0.5mm and a relative dielectric constant of ε r =2.2, and the loss tangent value is tanδ=0.0009. The first metal strip 100 and the second metal strip 101 are two orthogonal dipole antennas that are miniaturized by multiple bending. The first metal strip 100 and the second metal strip 101 are printed on the top and bottom surfaces of the dielectric substrate 10, respectively. The chip resistor 102 is a chip resistor with a resistance of R=250Ω. Figure 5 The other parameters are set as follows: unit period p = 25mm, l1 = 2mm, l2 = 1.2mm, l3 = 1mm, l4 = 3mm, w = 0.5mm.

[0070] Next, the absorbing layer structure was simulated and verified, and the periodic boundary conditions and Floquet ports in the ANSYS HFSS full-wave simulation software were used for excitation. The reflection coefficient and transmission coefficient of the absorbing layer were as follows: Figure 6 As shown in the simulation results, it can be seen that when the metal floor is loaded, the absorbing layer has two resonance points in the low frequency band, fl1 = 3.06 GHz and fl2 = 6.08 GHz, and in the frequency band of 2.53 to 6.64 GHz, S 11 <-10dB, relative bandwidth is 89.6%, showing good electromagnetic wave absorption performance in the low frequency band. When the metal floor is not loaded, the absorbing layer is in the medium and high frequency band of 6.5~18GHz, S 11Close to 0dB, that is, the transmission coefficient is approximately 1, with good electromagnetic wave transmission performance. Based on this, the metal floor can be replaced with an electromagnetic surface with full reflection characteristics in the low frequency band. On the one hand, it will not affect the absorption characteristics of the absorbing layer in the low frequency band. On the other hand, since the absorbing layer has extremely high transmission characteristics in the medium and high frequency bands, it will not affect other electromagnetic characteristics of the bottom electromagnetic surface, which is more conducive to the design of ultra-wideband structure.

[0071] See also Figure 7 , which is a schematic diagram of the structure of the first diffuse reflection layer 2 and the second diffuse reflection layer 3 provided in this embodiment, wherein the first diffuse reflection metal strip 20 and the second diffuse reflection metal strip 3 are both attached to a substrate having a relative dielectric constant ε r =2.2, loss tangent value tanδ=0.0009, the thickness of the dielectric plate is 0.254mm. The unit period is p / 2=6.25mm, and the repetition period of the double arrow of the second diffuse reflection layer is twice the repetition period of the double arrow of the first diffuse reflection layer. Figure 7 The other parameters are set as follows: t =9.5mm, L t1 =2.5mm, w t =0.5mm, L b =2.3mm, L b1 =3mm, w b =0.8mm. The double-arrow structure of the diffuse reflective metal can be regarded as a combination of an oblique V-shaped resonator and a tangent resonator. Define the direction parallel to the tangent resonator as the v-axis, and the direction perpendicular to the v-axis in the xoy plane as the u-axis. The resonant modes supported by a single oblique V-shaped resonator are excited by the electric field components along the v-axis and the u-axis respectively, and the multi-mode dipole resonance supported by a single tangent resonator is excited by the electric field components along the v-axis. Only a single double-headed arrow metal strip is discussed. In the case of v-polarization, the V-shaped resonator can be regarded as evolved from the tangent resonator, and the entire double-headed arrow plays the role of extending the tangent resonator. This extended tangent resonator couples with the metal ground, thereby exciting electromagnetic resonance. In the case of u-polarization, the V-shaped resonator is equivalent to a tangent resonator, and the coupling between the V-shaped resonator and the metal floor generates surface current, thereby generating electromagnetic resonance. Therefore, changing the geometric parameters of the double-headed arrow can change the resonant frequency, thereby obtaining an ultra-wideband diffuse reflective layer. In addition, the double-headed arrow structure can also convert the normally incident x-polarized wave into a y-polarized reflected wave, with a high conversion efficiency.

[0072] In order to verify the characteristics of the double diffuse reflection layer, the full-wave simulation software Ansys HFSS is used to simulate the diffuse reflection layer structure. The double diffuse reflection layer is arranged periodically along the x-axis and y-axis, and corresponds to the single-port incidence of the Floquet port. The simulation results are shown in Figure 8The black square dotted line is the reflection coefficient |S 11 |, indicating that when the polarization direction of the incident wave is along the x-axis and y-axis, strong cross-polarization reflection occurs, that is, after the incident wave along the x-polarization direction irradiates the double-headed arrow diffuse reflection layer, the polarization direction changes to the y-direction and is reflected back, such as Figure 8 |S 12 |As shown. Moreover, the cross-polarization reflection band of this structure is extremely wide, with resonance points at 6.1GHz, 11.0GHz and 19.5GHz, respectively. The polarization conversion efficiency at these three frequency points is close to 100%. |S 11 |<-10dB, the cross-polarization reflection band of x-polarized and y-polarized incident waves extends from 4.9GHz to 22GHz, and the electromagnetic wave energy is converted within the ultra-wide frequency band.

[0073] See also Fig. 9 , is a schematic diagram of the structure of the circularly polarized antenna body 4 provided in this embodiment, the unit period is p / 2=6.25mm, and the dielectric plates used are all relative dielectric constants ε r =2.2, Rogers RO5880 dielectric board with loss tangent value of tanδ=0.0009. The metal and dielectric of the circularly polarized antenna body 4 are arranged alternately, and the top layer is the parasitic patch layer 42, which is not directly connected to the feeding system, but interacts with the driving patch layer 43 through coupling, which can enhance the bandwidth and gain of the antenna. The driving patch layer 43 and the parasitic patch layer 42 are separated by a dielectric plate a, and the thickness of the dielectric plate a is 1mm. The driving patch layer 43 is a patch directly connected to the feeding system, responsible for sending and receiving signals. The size of the driving patch layer 43 can determine the basic performance of the antenna, such as operating frequency, gain and radiation pattern. The thickness of the metal plate b between the driving patch layer 43 and the first metal ground 44 is 1mm. The bottom layer of the circularly polarized antenna is a metal reflector, which can improve the gain and directivity of the antenna and reduce back radiation.

[0074] At the same time, there are two groups of blind holes. The first group of blind holes is used to penetrate the dielectric plate between the driving patch layer 43 and the first metal ground 44 and the first metal ground 44 and the one-to-four feeding network 41, and is used for the waveguide port to feed the driving patch layer 43 through the strip line; the second group of blind holes penetrates the dielectric layer between the first metal ground 44 and the second metal ground 45, in order to achieve mutual interference between the two feeding ports and reduce the electromagnetic coupling between the two feeding ports. The two waveguide ports can feed the electric fields in different directions of the antenna respectively, so that there is a 90° phase difference between the two orthogonal electric fields, and circular polarization is achieved. Fig. 9 The parameters of the medium circular polarization antenna body are as follows: the side length L of the parasitic patch layer 42 top=3.8mm, the side length L of the driving patch layer 43 btm =6.2mm, the diameter of the circular hole opened on the first metal ground 44 is g r =0.75mm, the diameter of the first group of blind holes p r =0.25mm, the length d of the one-to-four feeding network 41 f =1.4mm, the distance between the first group of blind holes and the second group of blind holes is d f1 =0.7mm, the diameter of the second set of blind holes p r1 =0.15mm.

[0075] The simulation tool Ansys HFSS2021 is used to simulate the circularly polarized antenna body. The simulation results of the standing wave ratio and axial ratio of the circularly polarized antenna body are obtained by using the radiation boundary condition. Fig.10 As shown. In the range of 13.1 to 14.5 GHz, VSWR is less than 2:1, and the axial ratio of the circularly polarized antenna body is less than 3 dB in the entire operating frequency band of the antenna. The driven patch layer works in the first frequency domain with the smallest axial ratio, and the parasitic patch layer works in the second frequency domain with the smallest axial ratio. The two interact with each other to achieve broadband circular polarization.

[0076] Next, the absorbing layer, two diffuse reflection layers and the circularly polarized antenna body are combined, and the combined antenna unit is simulated using Ansys HFSS2021, using radiation boundary conditions and waveguide port feeding. The simulation results of the antenna's axial ratio and standing wave ratio are shown in Figure 2. Fig.11 As shown, the standing wave ratio is less than 2 in the antenna working band of 13-15GHz, the axial ratio is less than 3dB, and it has very good circular polarization performance.

[0077] Fig.12 The gain values ​​of right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) are shown. The LHCP gain remains at a high level (about 10dB) throughout the frequency band. The antenna mainly produces left-hand circular polarization in this frequency band.

[0078] See also Fig.13 , showing an exploded diagram of the 8×8 array structure of circularly polarized antennas based on multi-mode frequency selective surfaces. The array structure consists of 8×8, a total of 64 circularly polarized antennas based on multi-mode frequency selective surfaces. The array structure size is 100mm×100mm, and is loaded with a 1-to-2 power divider and a 1-to-64 feeding network that rotates 90° in sequence. Coaxial feeding is used to achieve unified feeding of the entire antenna array. Coaxial feeding has the characteristics of simple structure, low loss, good impedance matching, and excellent shielding performance. It can reduce reflection loss, improve the transmission efficiency of the antenna, and has high adaptability.

[0079] The circularly polarized antenna array structure based on the multi-modal frequency selective surface is composed of an absorbing layer, a polarization conversion metasurface layer, a parasitic patch layer, a driving patch layer, a 90° one-to-two power divider, and a one-to-sixty-four feeding network from top to bottom. It is particularly important to note that in order to ensure good diffuse reflection performance, the polarization conversion metasurface is not obtained by translating the multi-modal radiation stealth integrated broadband low RCS circularly polarized antenna unit, but the double-headed arrow layer in the antenna unit is changed to a single-layer arrow pointing to the same unit structure, and it is ensured that the arrows of the two layers point perpendicular to each other along the positive z direction. The structure is then organized into a 4×4 subarray, and the subarray is rotated three times in sequence to form an 8×8 circularly polarized antenna array structure based on the multi-modal frequency selective surface.

[0080] Will Fig.13 The 8×8 circularly polarized antenna array structure based on the multi-mode frequency selective surface shown in the figure is simulated using CST. The results are as follows: Fig.14 and Fig.15 As shown. In the antenna operating frequency band of 13.0-15.0 GHz, the antenna axial ratio (AR) is less than 3 dB. The designed 8×8 array structure has excellent circular polarization performance, close to the ideal circular polarization state, and can effectively send and receive circularly polarized electromagnetic waves at various angles. In the antenna operating frequency band of 12.8-15.4 GHz, the standing wave ratio VSWR is less than 1.8, which meets the project index requirements, the antenna impedance matching is good, and the transmission efficiency is extremely high.

[0081] The RCS reduction value of the antenna is an important criterion for measuring the stealth performance of the antenna. The simulation results of the RCS reduction value of the designed 8×8 array structure are shown in the figure. Fig.16 and Fig.17 As shown. It can be seen that, whether it is TE polarization or TM polarization, in the working frequency band of 13 to 15 GHz, it has a good RCS suppression effect at different incident angles (0° to 20°), and the suppression amount is basically maintained above 10dB, which shows that the designed 8×8 array structure can significantly reduce the radar scattering cross-section of the target in the main working frequency band of the antenna and achieve electromagnetic stealth effect. The structure designed by us has outstanding RCS suppression performance under different polarization conditions and different incident angles. It not only achieves significant RCS reduction in the target working frequency band, but also can adapt to multi-angle and multi-polarization electromagnetic wave environments, reflecting the versatility and wide application potential of the structure. Especially for occasions with extremely high requirements for stealth performance such as satellite-borne array antennas, our structural design demonstrates a strong RCS reduction capability, which can effectively reduce the detectability of radar, while taking into account the radiation performance of the antenna, which is an important breakthrough in the field of stealth antennas.

[0082] In a second aspect, the present invention provides an integration method for manufacturing the circularly polarized antenna based on the multi-mode frequency selective surface provided in the first aspect, the integration method comprising the following steps:

[0083] A circularly polarized antenna body is provided, which includes, from top to bottom, a parasitic patch layer, a driving patch layer, a first metal ground, a 90° one-to-two power divider, a second metal ground, and a one-to-four feeding network;

[0084] An absorption layer is manufactured, and a dielectric substrate is provided, wherein the dielectric substrate comprises a first surface and a second surface opposite to each other, a first metal strip is etched on the first surface, and a second metal strip is etched on the second surface; the first metal strip and the second metal strip are perpendicular to each other but do not intersect, and chip resistors are arranged at the perpendicular points of the first metal strip and the second metal strip;

[0085] A first diffuse reflection layer is manufactured by providing a dielectric substrate, wherein the dielectric substrate has a first surface and a second surface opposite to each other, and the first surface is opposite to the wave absorbing layer; a plurality of first diffuse reflection regions are formed by dividing the first surface; first diffuse reflection metal strips arranged in a regular matrix are etched in each first diffuse reflection region; the first diffuse reflection metal strips in the same first diffuse reflection region have the same inclination direction; and the first diffuse reflection metal strips in adjacent first diffuse reflection regions are symmetrically arranged with adjacent sides as symmetry axes;

[0086] A second diffuse reflection layer is manufactured by providing a dielectric substrate, wherein the dielectric substrate has a first surface and a second surface opposite to each other, the first surface is opposite to the first diffuse reflection layer, and the first surface is divided into a plurality of second diffuse reflection areas, the number of the second diffuse reflection areas is the same as that of the first diffuse reflection areas, and the areas are equal, and one first diffuse reflection area corresponds to one second diffuse reflection area in space; second diffuse reflection metal strips arranged in a regular matrix are arranged in each second diffuse reflection area, and the inclination direction of the second diffuse reflection metal strips is perpendicular to the inclination direction of the first diffuse reflection metal strips in the corresponding first diffuse reflection area;

[0087] The absorption layer, the first diffuse reflection layer and the second diffuse reflection layer are sequentially integrated on the circular polarization antenna body from top to bottom.

[0088] In a third aspect, the present invention further provides a terminal, which uses the circularly polarized antenna based on the multi-mode frequency selective surface provided in the first aspect.

[0089] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the drawings, etc. In the specification, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit can implement several functions listed in the specification. Certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0090] Although the present invention has been described in conjunction with specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the present invention. Accordingly, this specification and the accompanying drawings are merely exemplary illustrations of the present invention and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present invention. Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, the present invention is intended to include such modifications and variations if they fall within the scope of the present invention and its equivalents.

Claims

1. A circularly polarized antenna based on a multi-mode frequency selective surface, characterized in that: On the circularly polarized antenna body, an absorbing layer, a first diffuse reflection layer and a second diffuse reflection layer are integrated in sequence from top to bottom; wherein the circularly polarized antenna body has an operating frequency band, the absorbing layer has an absorbing frequency band, the first diffuse reflection layer has a first diffuse reflection frequency band, and the second diffuse reflection layer has a second diffuse reflection frequency band; the operating frequency band neither crosses nor overlaps with the absorbing frequency band, the first diffuse reflection frequency band and the second diffuse reflection frequency band.

2. The circularly polarized antenna based on a multi-mode frequency selective surface according to claim 1, characterized in that: The wave absorbing layer includes a dielectric substrate, the dielectric substrate includes a first surface and a second surface opposite to each other, a first metal strip is formed on the first surface, a second metal strip is formed on the second surface, the first metal strip and the second metal strip are perpendicular to each other but do not intersect, and chip resistors are arranged at the perpendicular points of the first metal strip and the second metal strip.

3. The circularly polarized antenna based on a multi-mode frequency selective surface according to claim 2, characterized in that: The dielectric substrate is a rectangular dielectric substrate, the first metal strip is a first bent metal strip formed on a first diagonal line of the rectangular dielectric substrate, and the second metal strip is a second bent metal strip formed on a second diagonal line of the rectangular dielectric substrate.

4. The circularly polarized antenna based on a multi-mode frequency selective surface according to claim 1, characterized in that: The first diffuse reflection layer has a first surface and a second surface opposite to each other, the first surface is opposite to the wave absorbing layer; the first surface is divided into a plurality of first diffuse reflection areas; each of the first diffuse reflection areas is provided with first diffuse reflection metal strips arranged in a regular matrix; the first diffuse reflection metal strips in the same first diffuse reflection area have the same inclination direction; the first diffuse reflection metal strips in adjacent first diffuse reflection areas are symmetrically arranged with adjacent sides as symmetry axes; The second diffuse reflection layer has a first surface and a second surface opposite to each other, the first surface is opposite to the first diffuse reflection layer; the first surface is divided into a plurality of second diffuse reflection areas, the number and area of ​​the second diffuse reflection areas are the same as those of the first diffuse reflection areas, and one first diffuse reflection area corresponds to one second diffuse reflection area in space; second diffuse reflection metal strips arranged in a regular matrix are arranged in each of the second diffuse reflection areas, and the inclination direction of the second diffuse reflection metal strips is perpendicular to the inclination direction of the first diffuse reflection metal strips in the corresponding first diffuse reflection area.

5. The circularly polarized antenna based on a multi-mode frequency selective surface according to claim 4, characterized in that: A repetition period of the second diffuse reflection metal strips in the second diffuse reflection region is twice a repetition period of the first diffuse reflection metal strips in the corresponding first diffuse reflection region.

6. The circularly polarized antenna based on a multi-mode frequency selective surface according to claim 4, characterized in that: The first diffuse reflection metal strip and the second diffuse reflection metal strip are both straight line structures with arrows at both ends.

7. The circularly polarized antenna based on a multi-mode frequency selective surface according to claim 1, characterized in that: The circularly polarized antenna body is a circularly polarized antenna body configured with a 90° one-to-two power divider and a one-to-four feeding network.

8. The circularly polarized antenna based on a multi-mode frequency selective surface according to claim 7, characterized in that: The circularly polarized antenna body includes, in order from the direction close to the second diffuse reflection layer to the direction away from the second diffuse reflection layer, a parasitic patch layer, a driving patch layer, a first metal ground, a 90° one-to-two power divider, a second metal ground and a one-to-four feeding network; The parasitic patch layer is coupled with the driving patch layer and then connected to a 90° one-to-two power divider, and the 90° one-to-two power divider is fed by a one-to-four feeding network.

9. An integration method for manufacturing the circularly polarized antenna based on the multi-mode frequency selective surface according to any one of claims 1 to 8, the integration method comprising the following steps: A circularly polarized antenna body is provided, wherein the circularly polarized antenna body includes, from top to bottom, a parasitic patch layer, a driving patch layer, a first metal ground, a 90° one-to-two power divider, a second metal ground, and a one-to-four feeding network; Manufacturing an absorption layer, providing a dielectric substrate, the dielectric substrate comprising a first surface and a second surface opposite to each other, etching the first surface to form a first metal strip, and etching the second surface to form a second metal strip; the first metal strip and the second metal strip are perpendicular to each other but do not intersect, and chip resistors are provided at the perpendicular points of the first metal strip and the second metal strip; A first diffuse reflection layer is manufactured by providing a dielectric substrate, wherein the dielectric substrate has a first surface and a second surface opposite to each other, wherein the first surface is opposite to the wave absorbing layer; and a plurality of first diffuse reflection regions are formed on the first surface; First diffuse reflection metal strips arranged in a regular matrix are etched in each of the first diffuse reflection regions; the first diffuse reflection metal strips in the same first diffuse reflection region have the same inclination direction; the first diffuse reflection metal strips in adjacent first diffuse reflection regions are symmetrically arranged with adjacent sides as symmetry axes; A second diffuse reflection layer is manufactured by providing a dielectric substrate, wherein the dielectric substrate has a first surface and a second surface opposite to each other, the first surface is opposite to the first diffuse reflection layer, the first surface is divided into a plurality of second diffuse reflection areas, the number of the second diffuse reflection areas is the same as that of the first diffuse reflection areas, the areas are equal, and one first diffuse reflection area corresponds to one second diffuse reflection area in space; each of the second diffuse reflection areas is provided with second diffuse reflection metal strips arranged in a regular matrix, and the inclination direction of the second diffuse reflection metal strips is perpendicular to the inclination direction of the first diffuse reflection metal strips in the corresponding first diffuse reflection area; The absorption layer, the first diffuse reflection layer and the second diffuse reflection layer are sequentially integrated on the circularly polarized antenna body from top to bottom.

10. A terminal, characterized in that: The terminal applies the circularly polarized antenna based on the multi-mode frequency selective surface as described in any one of claims 1 to 8.

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