Protective antenna based on metasurface

Abstract

The invention belongs to the technical field of antennas, and relates to a protection antenna based on a metasurface, which comprises a dielectric layer, a radiation layer arranged on the upper surface of the dielectric layer, a floor layer arranged on the lower surface of the dielectric layer and a feed assembly, the radiation layer comprises a plurality of radiation patches which are arranged in a rectangular array so as to form a metasurface of which the length direction is parallel or vertical to the length direction of the dielectric layer; a diode is arranged between any two adjacent radiation patches along the length direction or the width direction of the metasurface; when the metasurface receives a normal signal, the diode is in a cut-off state; when the metasurface receives electromagnetic attack, the diode is in a conducting state; and electromagnetic protection of the antenna is realized through state switching of the diodes. According to the invention, the advantages of wide working frequency band, high tolerance power, low insertion loss and high integration level can be realized at the same time.

Description

Technical Field

[0001] The present application relates to the field of antenna technology, and in particular to a protective antenna based on a metasurface. Background Art

[0002] In recent years, with the advancement of electronic technology, the RF front-end link has been continuously developing in the direction of miniaturization and integration. The rated working power of various types of equipment varies, and it is inevitable that they will affect each other. The electromagnetic compatibility problem is becoming increasingly severe. In addition, with the threat of strong electromagnetic pulses in the future electromagnetic space, the need for protection of the RF front end is becoming increasingly urgent. However, the application method of traditional energy selective protection technology is still mainly to install it before and after the antenna, rather than integrating it with the antenna, which brings about the problem of insufficient compatibility. In order to further improve the compatibility of protection with the original antenna, it is necessary to study the integrated design method of energy selective protection function and antenna.

[0003] In the prior art, there are few public technical studies on protective antennas, and the main ideas include: phase defocusing the reflecting surface to achieve main lobe nulling, loading the feeding structure to achieve protection, and loading the radiating resonant structure to achieve resonant frequency offset reconstruction.

[0004] However, the existing technologies each have their own shortcomings: for the reflective surface defocusing protection antenna, its protection is spatially selective, and the protection effect is good only in the main lobe direction, and the bandwidth is narrow; for the protection antenna loaded with the feeding structure, it has the problem of insufficient power tolerance; for the resonant reconfigurable protection antenna, it mainly has the problem of narrow bandwidth. Summary of the invention

[0005] Based on this, it is necessary to provide a protective antenna based on a metasurface to address the above technical problems, which can simultaneously have the advantages of wide operating frequency band, high power tolerance, low insertion loss and high integration.

[0006] A protective antenna based on a metasurface, comprising: a dielectric layer, a radiation layer arranged on the upper surface of the dielectric layer, a floor layer arranged on the lower surface of the dielectric layer, and a feeding component; The radiation layer comprises: a plurality of radiation patches arranged in a rectangular array to form a metasurface whose length direction is parallel or perpendicular to the length direction of the dielectric layer; a diode is provided between any two adjacent radiation patches along the length direction or width direction of the metasurface; When the metasurface receives normal signals, the diode is in the cut-off state; when the metasurface receives electromagnetic attacks, the diode is in the on state; by switching the state of the diode, the electromagnetic protection of the antenna is achieved.

[0007] In one embodiment, along the length direction or width direction of the metasurface, a diode is provided between any two adjacent radiation patches, including: Along the length direction of the metasurface, a diode is provided between any two adjacent radiation patches; Alternatively, a diode is provided between any two adjacent radiation patches along the width direction of the metasurface.

[0008] In one embodiment, the center of the radiation layer coincides with the center of the upper surface of the dielectric layer.

[0009] In one embodiment, the radiation patch and the dielectric layer are both rectangular structures, and the length direction and width direction of the radiation patch are parallel to the dielectric layer.

[0010] In one embodiment, the ratio of the length of the radiation patch, the width of the radiation patch, and the distance between two adjacent radiation patches is 10:8:1. In one embodiment, the number of rows and columns of the metasurface is equal, and the distances between any adjacent radiation patches are equal.

[0011] In one embodiment, the feed assembly comprises: a coaxial connector and a rectangular probe disposed in the dielectric layer; The outer conductor of the coaxial connector is connected to the floor layer, and the inner conductor passes through the floor layer and is inserted into the dielectric layer and connected to the rectangular probe, so that the feeding assembly forms an "L"-shaped structure; The length direction of the rectangular probe is consistent with the conduction direction of the diode, so as to excite a leaky wave radiation mode along the conduction direction of the diode on the surface of the radiation layer.

[0012] In one embodiment, the rectangular probe is disposed on a symmetry axis of the radiation layer and passes through the center of the radiation layer.

[0013] In one embodiment, the length of the rectangular probe is equal to the sum of the length of the radiation patch and the distance between two adjacent radiation patches.

[0014] In one embodiment, the dielectric layer includes: a first dielectric plate and a second dielectric plate; The radiation layer is arranged on the upper surface of the first dielectric plate, the floor layer is arranged on the lower surface of the second dielectric plate, and the rectangular probe is arranged between the first dielectric plate and the second dielectric plate.

[0015] The above-mentioned metasurface-based protective antenna is designed with a radiation layer and a feeding component, integrating the energy selection protection function with the metasurface antenna radiation structure, loading the metasurface radiation structure with the protection function, and realizing electromagnetic protection by suppressing the antenna radiation mode under a strong field. It can ensure a consistent polarization direction, expand the range of electrical dimensions, and simultaneously stimulate the resonance of single nodes and multiple nodes, stimulate radiation modes of different frequencies, improve the operating frequency band and withstand power, and reduce insertion loss, thereby having the advantages of wide operating frequency band, high withstand power, low insertion loss, high protection efficiency, and high integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a side view of a metasurface-based protection antenna in one embodiment; Figure 2 is a top view of a metasurface-based protection antenna in one embodiment; Figure 3 A side-view dimensional diagram of a metasurface-based protective antenna in one embodiment; Figure 4 A top-down dimension diagram of a metasurface-based protective antenna in one embodiment; Figure 5 A rectangular probe size diagram of a metasurface-based protection antenna in one embodiment; Figure 6 is a diagram of an equivalent transmission line model of a metasurface-based protection antenna in one embodiment; Figure 7 is a dispersion diagram of a metasurface-based guard antenna in one embodiment; Figure 8 is a reflection coefficient diagram of a metasurface-based protection antenna in one embodiment; Fig. 9 is a main lobe gain comparison diagram of a metasurface-based protection antenna in one embodiment; Fig.10 A top view of a protective antenna based on a metasurface in one embodiment; Fig.11 A bottom view of a protective antenna based on a metasurface in one embodiment; Fig.12 A top view of a probe of a protective antenna based on a metasurface in one embodiment; Fig.13 A protection time domain waveform diagram of a protection antenna based on a metasurface in one embodiment; Fig.14 This is a comparison diagram between simulation and actual measurement of the protection effectiveness of a protection antenna based on a metasurface in one embodiment.

[0017] Reference numerals: Dielectric layer 1, first dielectric plate 11, second dielectric plate 12; Radiation layer 2, radiation patch 21, diode 22; Floor layer 3; Feeding assembly 4, coaxial connector outer conductor 41, coaxial connector inner conductor 42, rectangular probe 43, solder 44, through hole 45. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0019] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0020] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "multiple groups" means at least two groups, such as two groups, three groups, etc., unless otherwise clearly and specifically defined.

[0021] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0022] In addition, the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0023] The present application provides a protective antenna based on a metasurface, such as Figure 1 and Figure 2 (wherein the direction of the arrow is the direction of electric field polarization), in one embodiment, it includes: a dielectric layer, a radiation layer, a floor layer and a feeding component. The dielectric layer is a load-bearing component, providing loading space for the radiation layer and the floor layer.

[0024] The radiation layer is a radiation component, which is arranged on the upper surface of the dielectric layer, and includes: a plurality of radiation patches and a plurality of diodes; the radiation patches are arranged in a rectangular array and form a metasurface, and the length direction of the metasurface is parallel or perpendicular to the length direction of the dielectric layer; the diode is arranged between any two adjacent radiation patches along the length direction or width direction of the metasurface, specifically, along the length direction of the metasurface, a diode is arranged between any two adjacent radiation patches, or, along the width direction of the metasurface, a diode is arranged between any two adjacent radiation patches. The diode can be a PIN diode.

[0025] The floor layer is a grounding component, which is arranged on the lower surface of the dielectric layer and is a full-coverage floor.

[0026] The feeding assembly is a feeding component. In this embodiment, when the metasurface receives a normal signal, the diode is in a cut-off state; when the metasurface receives an electromagnetic attack, the diode is in a conducting state; and electromagnetic protection of the antenna is achieved by switching the state of the diode.

[0027] Preferably, the center of the radiation layer coincides with the center of the upper surface of the dielectric layer, so that the direction of the main lobe of the antenna is perpendicular to the radiation structure and the symmetry of the antenna radiation pattern is ensured.

[0028] Further preferably, the radiation patch and the dielectric layer are both rectangular structures, and the length and width directions of the radiation patch are parallel to the dielectric layer to form a standard radiation mode and ensure a good radiation pattern.

[0029] Further preferably, the ratio of the length of the radiation patch, the width of the radiation patch and the distance between two adjacent radiation patches is 10:8:1, so that the length of the radiation patch and the distance between two adjacent radiation patches achieve the matching frequency range of the antenna, and the width of the radiation patch and the distance between two adjacent radiation patches achieve the frequency range of high gain characteristics of the antenna radiation pattern, thereby working together to ensure the operating frequency band of the longitudinal leakage wave radiation mode and the transverse field distribution mode of the antenna, so that the antenna has both a large operating bandwidth and an antenna performance with a high gain radiation pattern within the bandwidth.

[0030] More preferably, the number of rows and columns of the metasurface are equal, and the distance between any adjacent radiating patches is equal, so as to improve the consistency of the main lobe width of the antenna E-plane and H-plane radiation patterns, and the greater the number of periods, the narrower the main lobe width in this direction.

[0031] In another embodiment, the feeding assembly includes: a coaxial connector and a rectangular probe; the outer conductor of the coaxial connector is connected to the floor layer, and the inner conductor passes through the floor layer and is inserted into the dielectric layer and connected to the rectangular probe, so that the feeding assembly forms an "L"-shaped structure; the rectangular probe is arranged in the dielectric layer, and its length direction is consistent with the conduction direction of the diode, so as to excite a leakage wave radiation mode along the conduction direction of the diode on the surface of the radiation layer.

[0032] Preferably, the rectangular probe is arranged on a symmetry axis of the radiation layer and passes through the center of the radiation layer to ensure the symmetry of the feeding, avoid the deviation of the main lobe direction of the antenna, and avoid the change of the working frequency band and radiation pattern of the antenna.

[0033] Further preferably, the length of the rectangular probe is equal to the sum of the length of the radiation patch and the distance between two adjacent radiation patches, so as to take into account the probe terminal capacitance effect, so that the distance from the vertical feeding point to the probe terminal of the rectangular probe is 1 / 4 wavelength, and after 4 unit cycles of the radiation structure, the TM10 leakage wave mode field distribution of the radiation structure is a full wavelength in the probe direction, thereby achieving better matching characteristics.

[0034] In another embodiment, the dielectric layer includes: a first dielectric plate and a second dielectric plate; the radiation layer is arranged on the upper surface of the first dielectric plate, the floor layer is arranged on the lower surface of the second dielectric plate, and the rectangular probe is arranged between the first dielectric plate and the second dielectric plate. The above arrangement can achieve the matching of the probe and the transmission line part. At the same time, due to the intrinsic broadband characteristics of the periodic structure of the metasurface, the probe is matched with the radiation structure through the probe coupling feeding method (rather than slot feeding or probe direct connection feeding), which can achieve broadband matching characteristics and avoid limiting the working bandwidth of the antenna.

[0035] Preferably, a through hole is provided on the first dielectric plate at a position corresponding to the connection between the coaxial connector and the rectangular probe, so that the solder at the connection between the coaxial connector (for example, SMA adapter) and the rectangular probe is arranged in the through hole, thereby ensuring the fit between the first dielectric plate and the second dielectric plate after welding and making the electrical connection more stable.

[0036] Note: Non-metallic studs (eg nylon studs) are provided at the four corners of the dielectric layer and the floor layer to connect and fix the various parts into a whole.

[0037] In this application, the working process of the antenna is as follows: the feed port is inserted from the back of the metal ground through a back-feed SMA connector, and an electrical connection with a rectangular probe is achieved through welding, and then coupled to the radiation layer through an L-shaped probe to radiate into free space. Based on this antenna, the metasurface is diode-loaded; when a normal working signal is transmitted to the antenna and the diode is cut off, the dispersion diagram of the radiation structure unit does not change significantly, and it can be transmitted normally to the feed port, and the TM10 leakage wave radiation mode is stimulated normally on the surface of the radiation layer (rather than perpendicular to the surface of the radiation layer). The wave radiates normally along the diode connection direction parallel to the metasurface, and the signal is received and sent normally; when a strong electromagnetic wave irradiates the antenna and the diode is turned on, the electromagnetic energy is reflected, and the TM10 transmission mode is cut off. By destroying the radiation mode of the antenna, it is impossible to receive and send signals and it cannot be transmitted to the feed port, thereby realizing the adaptive protection function.

[0038] From the perspective of impedance, after loading the diode, since the diode's own capacitance is small, the operating frequency is still far less than the resonant frequency. Therefore, loading the diode does not affect the normal working performance of the antenna. When the antenna is in the protection state, the diode is equivalent to a small resistor, which no longer satisfies the impedance matching and achieves protection.

[0039] From the perspective of radiation mode, the antenna can excite the TM10 leaky wave mode, which can couple the electromagnetic energy with the free space for propagation.

[0040] The above-mentioned metasurface-based protective antenna is designed with a radiation layer and a feeding component, integrating the energy selection protection function with the metasurface antenna radiation structure, loading the metasurface radiation structure with the protection function, and realizing electromagnetic protection by suppressing the antenna radiation mode under a strong field. It can ensure a consistent polarization direction, expand the range of electrical dimensions, and simultaneously stimulate the resonance of single nodes and multiple nodes, stimulate radiation modes of different frequencies, improve the operating frequency band and withstand power, and reduce insertion loss, thereby having the advantages of wide operating frequency band, high withstand power, low insertion loss, high protection efficiency, and high integration.

[0041] In a specific embodiment, the size parameters of the antenna are as follows: Figure 3 , Figure 4 , Figure 5 And as shown in Table 1.

[0042] Table 1: Antenna dimensions

[0043] The above antenna is simulated.

[0044] A transmission line unit model and an equivalent lumped circuit model are established for the radiation structure of the metasurface (a gap with a diode), and the equivalent transmission line model is obtained as shown in the figure below. Figure 6As shown, let the length of the transmission line unit in the x direction be Δx=px, and the equivalent series capacitance per unit length is C L is the equivalent lumped capacitance per unit length formed by the gap structure loaded between the radiation patches, and the equivalent series resistance R L is the equivalent lumped resistance of the gap as a radiation load, and the equivalent series inductance per unit length L R is the equivalent lumped inductance of the radiation patch structure, and the equivalent parallel capacitance per unit length C R It is the equivalent capacitance formed by the radiation patch and the metal ground. Under normal working conditions, the PIN diode is equivalent to a capacitor C off , then the antenna complex propagation constant γ off There is almost no change, and the leaky wave radiation mode can be normally generated to transmit energy to the free space; in the protection state, the PIN diode is equivalent to a small resistor Ron. At this time, the resistance is very small and can be ignored, and the propagation constant tends to 0. At this time, the antenna can hardly radiate normally, thereby realizing a strong electromagnetic protection function.

[0045] After simulation analysis, the results are as follows Figures 7 to 9 shown.

[0046] like Figure 7 The dispersion diagram of the protection antenna shown in the figure shows the propagation constant characteristics of the antenna radiation structure in the x direction. When the dispersion curve is lower than the dispersion curve of light, it means that the mode cannot radiate. Under normal working conditions, the dispersion curve in the 4.18-5.8GHZ range is above the light and can radiate normally; under the protection state, the dispersion curves are all below the light and cannot radiate normally in the same frequency range.

[0047] like Figure 8 The reflection coefficient diagram of the protection antenna is shown in Fig. 9 From the main lobe gain comparison diagram of the protection antenna shown, it can be found that the working frequency band (4.5-6GHz) of the protection antenna becomes a forbidden band after the diode is turned on, and signals cannot be received or sent. In the protection state, the reflection coefficient is significantly increased, while the gain is significantly decreased. Therefore, the loading of the diode can achieve the suppression of the radiation mode.

[0048] The above antennas were physically tested.

[0049] like Figures 10 to 12 The antenna shown in the figure is irradiated by a high-power microwave source with a frequency of 5.8GHz and a pulse width of 30ns. The field strength at the location of the antenna aperture is about 19440V / m. The field strength receiving antennas use a protection antenna and a control antenna respectively. The transmission oscilloscope is connected through an attenuator and a detector to compare the signal strengths received by the protection antenna and the control antenna. The measured protection time domain waveform is shown in the figure below. Fig.13As shown in the figure, it can be seen that the received signal has obvious attenuation when the protection antenna is used, and the attenuation value is about 21dB; the comparison between the protection effectiveness simulation and the actual measurement is shown in Fig.14 As shown, the actual measurement is basically consistent with the simulation prediction.

[0050] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0051] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A protective antenna based on a metasurface, characterized in that: include: A dielectric layer, a radiation layer arranged on the upper surface of the dielectric layer, a floor layer arranged on the lower surface of the dielectric layer, and a feeding assembly; The radiation layer comprises: a plurality of radiation patches arranged in a rectangular array to form a metasurface whose length direction is parallel or perpendicular to the length direction of the dielectric layer; A diode is provided between any two adjacent radiation patches along the length direction or the width direction of the metasurface; When the metasurface receives normal signals, the diode is in the cut-off state; when the metasurface receives electromagnetic attacks, the diode is in the on state; by switching the state of the diode, the electromagnetic protection of the antenna is achieved.

2. The protective antenna based on a metasurface according to claim 1, characterized in that: Along the length direction or width direction of the metasurface, a diode is provided between any two adjacent radiation patches, including: Along the length direction of the metasurface, a diode is provided between any two adjacent radiation patches; Alternatively, a diode is provided between any two adjacent radiation patches along the width direction of the metasurface.

3. A protective antenna based on a metasurface according to claim 1 or 2, characterized in that: The center of the radiation layer coincides with the center of the upper surface of the dielectric layer.

4. The protective antenna based on a metasurface according to claim 3, characterized in that: The radiation patch and the dielectric layer are both rectangular structures, and the length direction and width direction of the radiation patch are parallel to the dielectric layer.

5. The protective antenna based on a metasurface according to claim 4, characterized in that: The ratio of the length of the radiation patch, the width of the radiation patch and the distance between two adjacent radiation patches is 10:8:

1.

6. A protective antenna based on a metasurface according to claim 1 or 2, characterized in that: The number of rows and columns of the metasurface is equal, and the distances between any adjacent radiation patches are equal.

7. A protective antenna based on a metasurface according to claim 1 or 2, characterized in that: The feeding assembly comprises: a coaxial connector and a rectangular probe arranged in the dielectric layer; The outer conductor of the coaxial connector is connected to the floor layer, and the inner conductor passes through the floor layer and is inserted into the dielectric layer and connected to the rectangular probe, so that the feeding assembly forms an "L"-shaped structure; The length direction of the rectangular probe is consistent with the conduction direction of the diode, so as to excite a leaky wave radiation mode along the conduction direction of the diode on the surface of the radiation layer.

8. The protective antenna based on a metasurface according to claim 7, characterized in that: The rectangular probe is arranged on a symmetry axis of the radiation layer and passes through the center of the radiation layer.

9. The protective antenna based on a metasurface according to claim 8, characterized in that: The length of the rectangular probe is equal to the sum of the length of the radiation patch and the distance between two adjacent radiation patches.

10. The protective antenna based on a metasurface according to claim 9, characterized in that: The dielectric layer includes: a first dielectric plate and a second dielectric plate; The radiation layer is arranged on the upper surface of the first dielectric plate, the floor layer is arranged on the lower surface of the second dielectric plate, and the rectangular probe is arranged between the first dielectric plate and the second dielectric plate.

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