A polarization-selective electromagnetic protection circularly polarized antenna and methods of use thereof

Abstract

The application belongs to the field of antennas, and particularly relates to a polarization-selective electromagnetic protection circularly polarized antenna and a use method thereof. The polarization-selective electromagnetic protection circularly polarized antenna comprises an antenna radiation unit, a polarization control and protection unit, and a multi-feed network. The antenna radiation unit comprises a main radiator and a plurality of current coupling perturbation structures arranged on the main radiator. The polarization control and protection unit comprises at least two groups of protection structures and corresponding control elements. The two groups of protection structures are arranged corresponding to two orthogonal polarization directions of the antenna, and are selectively connected with the main radiator through the control elements. The multi-feed network comprises a plurality of feeds connected in a preset phase difference relationship, and is used for exciting the antenna radiation unit to generate circularly polarized radiation waves. The application provides a circularly polarized antenna which can realize polarization-selective protection and maintain communication ability under strong electromagnetic attack by switching the connection state of the protection structures through passive control elements and dynamically reconstructing the polarization characteristics of the antenna under high-power microwave incidence.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of antennas, and particularly relates to a polarization-selective electromagnetic protection circularly polarized antenna and a use method thereof. BACKGROUND

[0002] With the development of satellite technology, navigation systems have been widely used in various important fields, providing high-precision technical means for autonomous navigation positioning. Since circularly polarized antennas can weaken the Faraday effect, suppress multipath interference and improve the stability of the system, most of the navigation systems are loaded with circularly polarized antennas.

[0003] In recent years, with the continuous development and maturity of high-power microwave and pulse power technologies, strong electromagnetic attacks pose an unprecedented severe challenge to the electromagnetic safety of electronic information systems. Unlike the "soft kill" electromagnetic interference which aims to interfere with the normal operation of the system, strong electromagnetic attacks can directly cause physical damage to sensitive components in electronic information systems or even completely destroy them, thereby causing irreversible "hard kill" effects of the equipment. Strong electromagnetic protection can be divided into protection of "front door" and "back door", wherein the "front door" refers to the signal channel opened to the outside of the electronic equipment, such as antennas, sensors, etc., and the "back door" refers to the non-signal channel of the electronic equipment, such as apertures, ventilation holes, etc. The protection of the "front door" of the electronic equipment has always been the focus and difficulty in the field of electromagnetic protection. On the one hand, for electronic equipment, signal channels generally exist universally. When strong electromagnetic attacks reach the vicinity of the electronic equipment, strong electromagnetic energy can directly enter the radio frequency channel through the receiving antenna of the equipment almost without loss, thereby damaging sensitive electronic components in the equipment. On the other hand, for the signal channel of the electronic equipment, both normal transmission and reception of working signals and adaptive protection against strong electromagnetic attacks need to be realized, and how to realize the "functional compatibility" of the two is the core difficulty of protection design, and the related technology accumulation is currently still relatively weak. The existing electromagnetic protection antennas have the function of protecting against strong electromagnetic pulses, but the antennas cannot realize signal transmission and reception in the protection state. In view of the current situation of the protection requirements of navigation circularly polarized antennas, how to solve the functional compatibility of strong electromagnetic protection and signal transmission and reception has become a problem to be solved. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a polarization-selective electromagnetic protection circularly polarized antenna and a use method thereof. The present application provides a circularly polarized antenna which can dynamically reconstruct the polarization characteristics of the antenna by switching the protection structure connection state through a passive control element under high-power microwave incidence, so as to realize selective protection and maintain communication ability under strong electromagnetic attacks.

[0005] The present application provides a polarization-selective electromagnetic protection circularly polarized antenna, comprising:

[0006] The antenna radiating element includes a main radiator and multiple current-coupled perturbation structures disposed on the main radiator;

[0007] The polarization control and protection unit includes at least two sets of protection structures and corresponding control elements; the two sets of protection structures are arranged respectively corresponding to the two orthogonal polarization directions of the antenna, and are selectively connected to the main radiator through the control elements.

[0008] A multi-feed network, comprising multiple feeders connected with a preset phase difference relationship, is used to excite the antenna radiating element to generate circularly polarized radiation waves.

[0009] in,

[0010] Under normal operating conditions, the control element is in the first state, which disconnects the protective structure from the main radiator or makes a high-impedance connection, and the antenna maintains normal circular polarization radiation characteristics.

[0011] In electromagnetic protection mode, when an incident electromagnetic wave of a specific polarization is sensed, a set of control elements corresponding to the polarization direction switches to the second state, so that the corresponding protection structure is connected to the main radiator, thereby changing the radiation impedance of the polarization direction, so that the antenna switches from circular polarization working mode to linear polarization working mode to suppress the incident electromagnetic wave of a specific polarization, while maintaining the ability to receive cross-polarized signals.

[0012] When a high-power microwave attack with unknown polarization characteristics or composite polarization is detected, all control elements are switched to the second state, connecting all protective structures to the main radiator and causing the antenna to enter a total reflection state, thus achieving comprehensive protection against incident waves of arbitrary polarization.

[0013] Furthermore, the polarization control and protection unit includes four sets of protection structures and four control elements;

[0014] Four sets of protective structures are symmetrically arranged at the top, bottom, left, and right positions of the main radiator. The two sets of protective structures at the top and bottom positions are connected to the main radiator through two control elements to form a vertical polarization control branch. The two sets of protective structures at the left and right positions are connected to the main radiator through the other two control elements to form a horizontal polarization control branch.

[0015] The control element is a switching diode.

[0016] Furthermore, the protective structure is a metal patch structure, which is switchably connected to the main radiator via control elements;

[0017] When the corresponding control element is turned on, the protective structure, as a parasitic unit of the main radiator, changes the current distribution in the corresponding polarization direction, thereby causing impedance mismatch in that polarization direction.

[0018] Further, the current coupling perturbation structure is a metal structure which is not in contact with the main radiator and is arranged in a rotationally symmetric manner at the corner position of the main radiator, and is used to excite additional degenerate modes in the main radiator to compensate for the deterioration of the circular polarization axial ratio performance caused by loading the protection structure.

[0019] Further, the current coupling perturbation structure is an L-shaped metal patch arranged at four diagonal positions of the main radiator.

[0020] Further, the multi-feed network is a one-to-four feed network which includes one input port and four output feeds.

[0021] The four output feeds are connected to the four feed positions around the center of the main radiator in a spatially symmetric manner.

[0022] And the path lengths from the input port to the four output feeds are sequentially increased, so that the four feed outputs have a phase difference of 90° between them in sequence to meet the feed conditions for the antenna to generate circularly polarized radiation.

[0023] Further, the antenna radiation unit, the polarization control and protection unit and the multi-feed network are integrated on a double-layer dielectric substrate structure.

[0024] The double-layer dielectric substrate structure includes an upper dielectric substrate, a metal ground plate and a lower dielectric substrate arranged in sequence from top to bottom.

[0025] The main radiator and the current coupling perturbation structure are arranged on the upper surface of the upper dielectric substrate.

[0026] The multi-feed network is arranged on the lower surface of the lower dielectric substrate.

[0027] Further, a coaxial probe is also included, which is connected to the input port of the multi-feed network.

[0028] The metal ground plate is provided with isolation holes, and the output feeds of the multi-feed network are sequentially connected to the main radiator through the lower dielectric substrate, the isolation holes and the upper dielectric substrate.

[0029] Further, the dielectric constant of the upper dielectric substrate is between 9 and 10, and the loss tangent is not greater than 0.002; the dielectric constant of the lower dielectric substrate is between 4 and 5, and the loss tangent is not greater than 0.002.

[0030] The application also provides a use method of the polarization-selective electromagnetic protection circularly polarized antenna, which comprises the following steps:

[0031] Normal signal transceiving step: control all control elements to be in the first state, disconnect or connect with high impedance all protection structures from the main radiator, at this time the antenna works in circular polarization mode, and normal signal receiving and transmitting are carried out;

[0032] Polarization selection protection step: when high-power microwave attack is sensed, one of the following sub-steps is executed:

[0033] If the high-power microwave is horizontally polarized, control the control element corresponding to the horizontal polarization direction to switch to the second state, connect the corresponding protection structure with the main radiator, thereby suppressing the radiation of the antenna in the horizontal polarization mode, forcing the antenna to work in the vertical polarization mode, to protect the horizontal polarization attack and maintain the receiving ability of the vertical polarization signal;

[0034] If the high-power microwave is vertically polarized, control the control element corresponding to the vertical polarization direction to switch to the second state, connect the corresponding protection structure with the main radiator, thereby suppressing the radiation of the antenna in the vertical polarization mode, forcing the antenna to work in the horizontal polarization mode, to protect the vertical polarization attack and maintain the receiving ability of the horizontal polarization signal;

[0035] When high-power microwave attack with unknown polarization characteristics or composite polarization is sensed, control all control elements to switch to the second state, connect all protection structures with the main radiator, so that the antenna enters the full reflection state, and realizes comprehensive protection of any polarized incident wave.

[0036] The present application has the following beneficial effects:

[0037] 1. The strong electromagnetic protection and signal transceiving function compatibility are realized, through the state switching of the control element, the antenna can be quickly switched from the circular polarization working mode to the linear polarization mode which is orthogonal to the specific polarization mode when the strong electromagnetic attack in the specific polarization mode is suffered. This mechanism enables the antenna to form effective suppression on the incident attack polarization signal while still maintaining the receiving ability of the cross-polarized useful signal, fundamentally solving the technical problem that the traditional electromagnetic protection antenna cannot work normally in the protection state. In addition, in the comprehensive protection state (all control elements are turned on), the antenna gain sharply decreases to-13.4dBi, which is 18.4dBi lower than that in the normal working state, indicating that most of the attack energy is reflected, and effective protection is achieved.

[0038] 2. The selective and adaptive protection ability of the incident electromagnetic wave polarization is possessed, since the protection structures are arranged in groups according to the orthogonal polarization direction and can be independently controlled, the present application can selectively suppress the corresponding polarization mode of the antenna according to the polarization characteristics of the incident high-power microwave, realize precise and adaptive protection of different polarization attacks, and improve the survival ability and complex electromagnetic environment adaptability of the antenna.

[0039] 3. Even after the introduction of protection functions, it still maintains excellent circular polarization performance. The current-coupled perturbation structure effectively compensates for the impact on the inherent performance of the antenna caused by the loading of the protection structure, ensuring that the antenna has good circular polarization radiation characteristics such as low axial ratio and high gain under normal working conditions, which meets the stringent requirements of navigation systems for antenna performance.

[0040] 4. Significant performance changes under protection mode, reliable protection effect. Experimental data shows that when the control element switches to protection mode, the radiation impedance of the antenna in the corresponding polarization direction changes significantly, the axial ratio deteriorates sharply, and the gain decreases significantly. This proves that the scheme can effectively disrupt the normal receiving conditions of the antenna, reflect most of the attacking electromagnetic energy, and achieve reliable protection for sensitive electronic components at the back end.

[0041] 5. The overall structure is compact and the performance is stable. It integrates radiation, feeding and protection functions in a limited space, ensuring the electrical performance of the antenna in terms of operating bandwidth and beamwidth. At the same time, the structure is robust and easy to integrate and apply.

[0042] In summary, this invention provides a high-performance, highly reliable navigation circularly polarized antenna with intelligent electromagnetic protection capabilities. Attached Figure Description

[0043] Appendix Figure 1 A top view of the electromagnetically protected circularly polarized antenna of the present invention;

[0044] Appendix Figure 2 A bottom view of the electromagnetically protected circularly polarized antenna of this invention;

[0045] Appendix Figure 3 This is a front view of the electromagnetically protected circularly polarized antenna of the present invention.

[0046] Appendix Figure 4 This is the equivalent circuit model of the antenna when the diode is cut off according to the present invention;

[0047] Appendix Figure 5 This is the equivalent circuit model of the antenna when the diode is turned on, according to the present invention.

[0048] Appendix Figure 6 This is a diagram showing the antenna reflection coefficient when the diode is off and on in this invention.

[0049] Appendix Figure 7 The diagrams show the diode's polarity when it is off and when it is horizontally conducting.

[0050] Appendix Figure 8 The antenna pattern is shown when the diode is cut off and when the diode is perpendicularly turned on according to the present invention.

[0051] Appendix Figure 9Antenna pattern when diode is off and when diode is fully on for the present invention;

[0052] Attached Figure 10 Antenna axial ratio pattern when diode is off and when diode is on for the present invention;

[0053] Attached Figure 11 Antenna circular polarization component pattern when diode is off for the present invention;

[0054] Attached Figure 12 Antenna linear polarization component pattern when diode is horizontal on for the present invention;

[0055] Attached Figure 13 Antenna linear polarization component pattern when diode is vertical on for the present invention.

[0056] In the figure, 1-main radiator; 2-current coupling perturbation structure; 3-protection structure; 4-feeding position; 5-output feed I; 6-output feed II; 7-output feed III; 8-output feed IV; 9-input port; 10-upper layer dielectric substrate; 11-lower layer dielectric substrate; 12-coaxial probe; 13-one-to-four feed network; 14-metal floor; 15-feeding metal column; 16-control element I; 17-control element II; 18-control element III; 19-control element IV. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0058] It should be noted that all the directionality indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the directionality indications also change accordingly.

[0059] In addition, the descriptions such as "first", "second" and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0060] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0061] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0062] like Figures 1-13 As shown, the present invention provides a polarization-selective electromagnetically protected circularly polarized antenna, comprising:

[0063] The antenna radiating element includes a main radiator 1 and multiple current-coupled perturbation structures 2 disposed on the main radiator 1;

[0064] The polarization control and protection unit includes at least two sets of protection structures 3 and corresponding control elements; the two sets of protection structures 3 are respectively arranged in two orthogonal polarization directions of the antenna, that is, one set forms a vertical polarization control branch and the other set forms a horizontal polarization control branch, and are selectively connected to the main radiator 1 through the control elements;

[0065] A multi-feed network, comprising multiple feeders connected with a preset phase difference relationship, is used to excite the antenna radiating element to generate circularly polarized radiation waves.

[0066] in,

[0067] Under normal operating conditions, the control element is in the first state, which disconnects the protective structure 3 from the main radiator 1 or makes a high-impedance connection, and the antenna maintains normal circular polarization radiation characteristics.

[0068] In electromagnetic protection mode, when an incident electromagnetic wave of a specific polarization is sensed, a set of control elements corresponding to the polarization direction switches to the second state, so that the corresponding protection structure 3 is connected to the main radiator 1, thereby changing the radiation impedance of the polarization direction, so that the antenna switches from circular polarization working mode to linear polarization working mode to suppress the incident electromagnetic wave of a specific polarization, while maintaining the ability to receive cross-polarized signals.

[0069] When a high-power microwave attack with unknown or complex polarization characteristics is sensed, all the control elements are switched to the second state to connect all the protection structures 3 to the main radiator 1, so that the antenna enters the full reflection state and realizes comprehensive protection against any polarized incident wave.

[0070] In one of the embodiments, the polarization control and protection unit includes four groups of protection structures 3 and four control elements; wherein the four control elements are control element I 16, control element II 17, control element III 18 and control element IV 19 respectively.

[0071] The four groups of protection structures 3 are symmetrically arranged at the upper, lower, left and right positions of the main radiator 1, wherein the two groups of protection structures 3 at the upper and lower positions are connected to the main radiator 1 through two control elements, specifically, the protection structure 3 at the upper position is connected to the main radiator 1 through the control element I 16, and the protection structure 3 at the lower position is connected to the main radiator 1 through the control element III 18, forming a vertical polarization control branch. The two groups of protection structures 3 at the left and right positions are connected to the main radiator 1 through the other two control elements, forming a horizontal polarization control branch, specifically, the protection structure 3 at the left position is connected to the main radiator 1 through the control element II 17, and the protection structure 3 at the right position is connected to the main radiator 1 through the control element IV 19.

[0072] The control element is a switch diode.

[0073] In this embodiment, the four groups of protection structures 3 are symmetrically arranged at the upper, lower, left and right positions, and form symmetric coupling with the main radiator 1, ensuring that when any polarization branch is controlled, the change of the antenna radiation mode has good symmetry and consistency, avoiding the deterioration of polarization purity or the distortion of the directional diagram caused by the asymmetric structure. The protection structures 3 are clearly divided into two independent control branches of vertical and horizontal, so that the antenna can accurately select the corresponding polarization mode according to the polarization characteristics of the incident electromagnetic wave, thereby maximizing the signal receiving ability in the orthogonal polarization direction when protecting against a specific polarization attack. In addition, the switch diode is used as the control element, and the impedance characteristics of the on / off state are significantly different, which realizes the rapid and reliable switching of the connection state between the protection structure 3 and the main radiator 1. This design ensures that the antenna can respond to a sudden high-power microwave attack within milliseconds, meeting the real-time protection requirements in actual environment.

[0074] By grouping the four control elements into two branches according to the polarization direction, the design of the external control circuit is greatly simplified. In practical application, only two control signals are needed to realize comprehensive protection against four typical polarization attack scenarios (horizontal, vertical, circular polarization and arbitrary polarization), improving the engineering realizability and reliability of the system.

[0075] In one of the embodiments, the protection structure 3 is a metal patch structure, which is switchably connected to the main radiator 1 by a control element;

[0076] When the corresponding control element is turned on, the protection structure 3 acts as a parasitic element of the main radiator 1, changes the current distribution of the corresponding polarization direction, and further causes impedance mismatch of the polarization direction.

[0077] In this embodiment, the protection structure 3 can be switched between the electrically isolated and strongly coupled modes by the on-off state of the control element. When the control element is turned on, the protection structure 3 acts as an effective parasitic element, which can significantly change the current distribution of the corresponding polarization direction, thereby realizing dynamic reconstruction of the antenna from circular polarization to linear polarization. The access of the protection structure 3 essentially changes the equivalent circuit parameters of the antenna in a specific polarization direction. This change directly leads to a serious impedance mismatch in the polarization direction, so that most of the incident energy is reflected rather than absorbed or transmitted, thereby realizing efficient protection of high-power microwaves at the circuit level. When the control element is turned off, the protection structure 3 is connected to the main radiator 1 with high impedance, which is almost invisible in electricity, ensuring that the antenna maintains its original circular polarization performance in the normal working state.

[0078] In one of the embodiments, the current-coupled perturbation structure 2 is a metal structure that is non-contact coupled to the main radiator 1 and arranged in a rotationally symmetric manner at the corner position of the main radiator 1, for exciting additional degenerate modes in the main radiator 1 to compensate for the deterioration of the circular polarization axial ratio performance caused by loading the protection structure 3.

[0079] In this embodiment, additional degenerate modes are excited in the main radiator 1 by non-contact coupling, which specifically compensates for the circular polarization purity destroyed by loading the protection structure 3, so that the antenna can still maintain excellent axial ratio characteristics (simulation up to 0.66 dB) after integrating the protection function, solving the technical problem of the circular polarization performance degradation caused by structural changes in traditional protection antennas.

[0080] In addition, the non-contact coupling method avoids the destructive interference of direct connection to the current distribution of the main radiator 1, which not only realizes the performance compensation function, but also maintains the integrity and independence of the main radiator 1 structure, ensuring the stability of the basic radiation performance of the antenna.

[0081] The rotationally symmetric arrangement ensures that the antenna obtains balanced compensation effect in two orthogonal polarization directions, maintains the condition of equal amplitude and orthogonal phase required for circular polarization, and prevents polarization ellipse distortion caused by uneven compensation.

[0082] The current-coupled perturbation structure 2 as an independent compensation unit, without additional active circuit or complex tuning network, realizes performance optimization only through its specific shape, position and coupling relationship, greatly simplifies the overall design and debugging difficulty of the antenna. That is, through the passive structure compensation mechanism, the introduction of active control link is avoided, the working reliability of the system is improved, and the stable circularly polarized performance of the antenna in the long-term use process is ensured, which is not affected by the control circuit failure or power fluctuation.

[0083] In one of the embodiments, the current-coupled perturbation structure 2 is an L-shaped metal patch, which is arranged at four diagonal positions of the main radiator 1.

[0084] In this embodiment, the asymmetric characteristics of the L-shaped metal patch structure enable it to simultaneously excite two degenerate modes with equal amplitude and orthogonal phase in the main radiator 1. The improvement effect of this specific shape of perturbation on circular polarization performance is significantly better than that of a simple square or circular patch. The simulation can optimize the axial ratio to an excellent level of 0.66dB. The two arms of the L-shaped metal patch structure correspond to the two orthogonal polarization directions of the antenna, respectively, and can independently adjust the corresponding degenerate mode separation, realizing precise regulation and control of the circular polarization performance. This directional regulation and control capability enables the optimal circular polarization performance to be quickly restored by fine-tuning the size of the L-shaped metal patch structure after loading the protection structure 3. Precise arrangement of the L-shaped metal patch structure at the four diagonal positions fully utilizes the characteristic points of the current distribution on the main radiator 1, ensuring rotational symmetry and maximizing the perturbation effect. This layout method makes the compensation effect uniform in the entire radiation range, avoiding the problem of asymmetric pattern. The length, width and arm ratio of the L-shaped metal patch structure can be adjusted as independent parameters, providing multiple dimensions of debugging freedom for antenna design, enabling the antenna performance to be quickly optimized for different specific application requirements, and enhancing the adaptability and flexibility of the design. The L-shaped metal patch structure realizes the maximum electrical size in a limited space, while maintaining the same compensation effect, thereby maximizing the layout space and helping to realize the miniaturization design of the antenna.

[0085] In one of the embodiments, the multi-feed network is a four-way feed network 13, which includes an input port 9 and four output feeds; the four output feeds are output feed I 5, output feed II 6, output feed III 7 and output feed IV 8 in turn;

[0086] The four output feeds are connected to the four feed positions 4 around the center of the main radiator 1 in a spatially symmetric manner;

[0087] And, the path lengths from the input port 9 to the four output feeds are sequentially increased, so that the four feed outputs have a phase difference of 90° between them in sequence, to meet the feed conditions for the antenna to generate circularly polarized radiation.

[0088] In this embodiment, the design of sequentially increasing path lengths by λ / 4 provides a 90° phase difference generation scheme with simple structure and reliable performance. This scheme is not sensitive to processing tolerances, has good repeatability and stability, and is convenient for mass production. In addition, by precisely controlling the 90° phase difference between the four output feeds, the necessary excitation conditions for the antenna to generate high-quality circularly polarized waves are provided. The four output feeds are arranged in a spatially symmetric manner around the center of the main radiator 1, ensuring that the antenna obtains completely symmetric excitation in two orthogonal polarization directions, and avoiding the degradation of circular polarization performance caused by asymmetric feeding.

[0089] The one-to-four feed network 13 converts a single input into four outputs with specific phase relationships, achieving high integration of the circularly polarized feed function. Only a single radio frequency input is required externally, greatly simplifying the system connection and integration difficulty of the antenna and subsequent circuits.

[0090] Preferably, the four output feeds are connected to the feed positions 4 on the main radiator 1 through feed metal columns 15.

[0091] In one embodiment, the antenna radiation unit, polarization control and protection unit, and multi-feed network are integrated on a double-layer dielectric substrate structure.

[0092] The double-layer dielectric substrate structure includes, from top to bottom, an upper dielectric substrate 10, a metal ground plate 14, and a lower dielectric substrate 11.

[0093] Among them, the main radiator 1 and the current-coupled perturbation structure 2 are arranged on the upper surface of the upper dielectric substrate 10.

[0094] The multi-feed network is arranged on the lower surface of the lower dielectric substrate 11.

[0095] In the embodiment, the antenna radiation unit and the multi-feed network are arranged on the upper and lower layers respectively, realizing the physical isolation and functional division of the radiation system and the feed system, effectively reducing the parasitic coupling of the feed network to the radiation field, and ensuring the stability of the antenna radiation direction and the consistency of the radiation pattern. The metal floor 14 located in the middle layer acts as an effective electromagnetic shielding layer, preventing the electromagnetic energy of the one-to-four feed network 13 in the lower layer from leaking to the upper layer radiation unit, while suppressing the interference of the upper layer radiation field on the lower layer sensitive feed circuit, significantly improving the electromagnetic compatibility and working stability of the whole antenna. The use of laminated three-dimensional structure realizes the integration of multiple functions in limited planar space, greatly optimizes the profile size of the antenna, realizes the compactness of the structure, and is convenient for integrated installation in modern electronic equipment. In addition, the laminated structure makes the functional layers of the antenna combine into a solid whole, improves the mechanical strength and vibration resistance of the antenna, and the sealed structure also enhances the protection ability of the antenna against environmental factors such as moisture and dust, prolongs the service life.

[0096] In one of the embodiments, a coaxial probe 12 is further included, which is connected to the input port 9 of the multi-feed network;

[0097] The metal floor 14 is provided with isolation holes, and the output feed of the multi-feed network is connected with the main radiator 1 in sequence through the lower layer dielectric substrate 11, the isolation holes and the upper layer dielectric substrate 10. Specifically, the output feed is connected with the feed position 4 of the main radiator 1 through the feed metal column 15, that is, the feed metal column 15 is provided with four metal columns, one end of each metal column is connected with the output feed, and the other end is connected with the feed position 4, and the feed metal column 15 passes through the lower layer dielectric substrate 11, the isolation holes and the upper layer dielectric substrate 10 in sequence.

[0098] In the embodiment, the coaxial probe 12 provides a low-loss and anti-interference transmission path from the external circuit to the multi-feed network, ensuring that the radio frequency signal can be efficiently transmitted from the input port 9 to the lower layer multi-feed network, and providing stable and reliable signal input protection for the whole antenna system. The isolation holes provided on the metal floor 14 enable the output feed of the multi-feed network to safely pass through the metal floor 14 while maintaining electrical isolation with the metal floor 14, effectively preventing the risk of short circuit between the input port 9 and the metal floor 14, and ensuring the normal operation of the circuits between the layers of the antenna.

[0099] Preferably, the coaxial probe 12 includes an interface and a mounting leg, and the mounting leg is fixed with the upper layer dielectric substrate 10 after passing through the lower layer dielectric substrate 11 and the metal floor 14. At this time, the mounting leg is fixedly connected with the upper layer dielectric substrate 10 after passing through the lower layer dielectric substrate 11 and the metal floor 14, providing an additional mechanical support point for the coaxial probe 12, effectively preventing the connection from loosening due to vibration or temperature change, and improving the reliability of the antenna in harsh environments.

[0100] In one embodiment, the dielectric constant of the upper dielectric substrate 10 is between 9 and 10, and the loss tangent is not greater than 0.002; the dielectric constant of the lower dielectric substrate 11 is between 4 and 5, and the loss tangent is not greater than 0.002.

[0101] The upper dielectric substrate 10 uses a material with a high dielectric constant, which facilitates the miniaturization of the radiating element; the lower dielectric substrate 11 uses a material with a low dielectric constant, reducing the transmission loss of the feed network. This material combination maximizes feed efficiency while ensuring antenna radiation performance. The loss tangent of both the upper dielectric substrate 10 and the lower dielectric substrate 11 is no higher than 0.002, minimizing the absorption loss of radio frequency energy by the dielectric material, significantly improving the antenna's radiation efficiency and overall gain, and providing reliable signal reception for the navigation system.

[0102] The present invention also provides a method for using the above-mentioned polarization-selective electromagnetic protection circularly polarized antenna, comprising the following steps:

[0103] Normal signal transmission and reception steps: Control all control elements to the first state, so that all protective structures 3 are disconnected from the main radiator 1 or connected with high impedance. At this time, the antenna works in circular polarization mode to receive and transmit signals normally.

[0104] Polarization Selective Protection Procedure: When a high-power microwave attack is detected, perform one of the following sub-steps:

[0105] If the high-power microwave is horizontally polarized, the control element corresponding to the horizontal polarization direction is switched to the second state, so that the corresponding protective structure 3 is connected to the main radiator 1, thereby suppressing the radiation of the antenna in the horizontal polarization mode and forcing the antenna to work in the vertical polarization mode to protect against horizontal polarization attacks and maintain the ability to receive vertical polarization signals.

[0106] If the high-power microwave is vertically polarized, the control element corresponding to the vertical polarization direction is switched to the second state, so that the corresponding protective structure 3 is connected to the main radiator 1, thereby suppressing the radiation of the antenna in the vertical polarization mode and forcing the antenna to work in the horizontal polarization mode to protect against vertical polarization attacks and maintain the ability to receive horizontal polarization signals.

[0107] When a high-power microwave attack with unknown polarization characteristics or composite polarization is detected, all control elements are switched to the second state, connecting all protective structures 3 to the main radiator 1, causing the antenna to enter a total reflection state, thus achieving comprehensive protection against incident waves of arbitrary polarization.

[0108] The method can realize electromagnetic protection with compatible functions in a circularly polarized antenna. By accurate polarization control, the receiving ability of cross-polarized signals can be maintained when resisting specific polarization attacks, and the technical bottleneck of complete communication interruption during protection of a traditional protection antenna is overcome. In addition, the full reflection state is started only when necessary, so that the availability of the communication link is maximally maintained under the premise of ensuring safety, and system resources and energy consumption are optimized.

[0109] The application also provides a specific embodiment, which can be specifically referred to Figures 1-5 .

[0110] The application also provides a specific embodiment, which can be specifically referred to Figure 1 , wherein, in the figure, 1 is a main radiator, which adopts a rectangular patch with a length of 28.1 mm and a width of 27.8 mm; 2 is a current coupling perturbation structure, which is composed of two rectangles with a length of 14.0 mm and a width of 10.0 mm and is made into an L shape, the structure adopts a non-contact current coupling perturbation design, and the structure compensates for the decrease in the axial ratio performance of the circularly polarized antenna caused by the protection structure 3 while not affecting the protection effect of the antenna. In order to ensure that the circularly polarized performance and the protection performance of the antenna are optimal, the antenna structure needs to be symmetrical, so the antenna current perturbation structure is located at the upper left, lower left, upper right and lower right of the main radiator 1; 3 is a protection structure, which is made into a rectangle with a length of 9 mm and a width of 6.8 mm, the protection structure 3 is connected with the main radiator 1 through control elements, four control elements are control element I 16, control element II 17, control element III 18 and control element IV 19, wherein the control element I 16 and the control element III 18 are horizontal diodes, and the control element II 17 and the control element IV 19 are vertical diode control elements, the control elements adopt diodes. When high-power microwaves are incident, the diodes are turned on, the protection structure 3 is connected with the main radiator 1 through the diodes, the antenna radiation structure is changed, the normal operation of the antenna is inhibited, and thus the electromagnetic protection function is realized, and the protection structure 3 is located at the upper, lower, left and right of the main radiator 1; 4 is a feeding position, which is located at positions offset by 4 mm upward, 4 mm downward, 4 mm leftward and 4 mm rightward from the center of the antenna respectively.

[0111] The application also provides a specific embodiment, which can be specifically referred to Figure 2 , wherein four output feedings of the multi-feed network are output feeding I 5, output feeding II 6, output feeding III 7 and output feeding IV 8 in sequence; the line length of the multi-feed network from an input port 9 to the output feeding I 5, the output feeding II 6, the output feeding III 7 and the output feeding IV 8 increases by one quarter of a wavelength in sequence, so that the feeding phases meet the circularly polarized feeding condition, that is, each feeding phase is different by 90°.

[0112] The application also provides a specific embodiment, which can be specifically referred to Figure 3, 10 is an upper layer dielectric substrate, the size is a square with a side length of 65.5mm, the dielectric material is TP960, the dielectric constant is 9.6, the loss tangent is 0.0012, and the thickness is 3mm; 11 is a lower layer dielectric substrate, the size is consistent with the upper layer dielectric substrate 10, the dielectric material is TP440, the dielectric constant is 4.4, the loss tangent is 0.001, and the thickness is 1.5mm; 12 is a coaxial probe, the coaxial probe 12 is embedded in the upper layer dielectric substrate 10 and connected with a one-to-four feed network 13; 14 is a metal ground plate, the size is consistent with the upper layer dielectric substrate 10, and an isolation hole is formed in the metal ground plate 14 with the feed position 4 as the center and with a radius of 1.2mm, so that the feed metal column 15 passes through, the function of the isolation hole is to isolate the feed metal column 15 from the metal ground plate 14 when the feed metal column 15 passes through the metal ground plate 14, to avoid short circuit and to enable the feed metal column 15 to connect the main radiator 1 and the one-to-four feed network 13.

[0113] Reference Figure 4 , wherein L is the transmission line length from the input port 9 to the output feed I 5, L+λ / 4 is the transmission line length from the input port 9 to the output feed II 6, L+2λ / 4 is the transmission line length from the input port 9 to the output feed III 7, and L+3λ / 4 is the transmission line length from the input port 9 to the output feed IV 8. L1, C1 and R1 are equivalent to the equivalent resonance circuit of the antenna when the output feed I 5 is fed, L2, C2 and R2 are equivalent to the equivalent resonance circuit of the antenna when the output feed II 6 is fed, L3, C3 and R3 are equivalent to the equivalent resonance circuit of the antenna when the output feed III 7 is fed, and L4, C4 and R4 are equivalent to the equivalent resonance circuit of the antenna when the output feed IV 8 is fed. When the diode is cut off, it is equivalent to a parallel capacitor of the antenna, so C D1 , C D2 , C D3 , C D4 is the equivalent capacitor of the antenna in parallel when the diode is cut off.

[0114] Reference Figure 5 When the diode is turned on, it is equivalent to a parallel resistor, so R D1 , R D2 , R D3 , R D4 is the equivalent resistance of the antenna in parallel when the diode is turned on. When horizontal polarized high-power microwave is incident, the diode is turned on in the horizontal direction, the equivalent capacitor C D1 , C D3 of the diode in parallel becomes the equivalent resistance R D1 , R D3 of the diode in parallel, at this time, the real part impedance of the antenna feed in the horizontal direction changes, resulting in impedance mismatch of the antenna feed in the horizontal direction, so the antenna changes from circular polarization to vertical polarization; when vertical polarized high-power microwave is incident, the diode is turned on in the vertical direction, the equivalent capacitor CD2 , C D4 becomes the parallel diode equivalent resistance R D2 , R D4 At this time, the real part impedance of the antenna vertical direction feed changes, resulting in the impedance mismatch of the antenna vertical direction feed, so the antenna changes from circular polarization to horizontal polarization.

[0115] The application aims to independently inhibit the two orthogonal degenerate modes of the circularly polarized antenna through the designed protection structure 3, that is, when the diode is cut off, the antenna works normally and keeps the circularly polarized radiation characteristics; when the horizontal polarized high-power microwave is incident, the diode in the horizontal direction is turned on, the protection structure 3 in the horizontal direction of the antenna is connected with the main radiator 1, the mode work in the horizontal direction is inhibited, so that the antenna polarization changes from circular polarization to vertical polarization, and the horizontal polarized high-power microwave is protected; when the vertical polarized high-power microwave is incident, the diode in the vertical direction is turned on, the protection structure 3 in the vertical direction of the antenna is connected with the main radiator 1, the mode work in the vertical direction is inhibited, so that the antenna polarization changes from circular polarization to horizontal polarization, and the vertical polarized high-power microwave is protected; when the diode in the horizontal direction and the diode in the vertical direction are both turned on, the protection structure 3 in the horizontal direction and the protection structure 3 in the vertical direction are both connected with the main radiator 1, so that the antenna cannot work normally and enters the total reflection state, and the incident signal is not received.

[0116] Through the experiment verification, the application has good effects, and specifically:

[0117] Reference Figure 6 When the antenna works normally, the working frequency band is 1.528GHz-1.579GHz, and the relative bandwidth is 3.3%; when the horizontal polarized high-power microwave is incident, the diode in the vertical direction is cut off, and the diode in the horizontal direction is turned on, the working frequency band of the antenna is 1.563GHz-1.601GHz; when the vertical polarized high-power microwave is incident, the diode in the horizontal direction is cut off, and the diode in the vertical direction is turned on, the working frequency band of the antenna is 1.517GHz-1.542GHz.

[0118] When the frequency is 1.561098GHz, the gain of the antenna when working normally is 5.0dBi, and the half-power beam width is 103.8°x105.4°; when the horizontal polarized high-power microwave is incident, the diode in the horizontal direction is turned on, and the diode in the vertical direction is cut off, the gain of the antenna is 4.0dBi, and the half-power beam width is 108.7°x101.9°, as shown in Figure 7 When the vertical polarized high-power microwave is incident, the diode in the vertical direction is turned on, and the diode in the horizontal direction is cut off, the gain of the antenna is 3.1dBi, and the half-power beam width is 99.8°x108.4°, as shown in Figure 8As shown in the figure; when the diodes are all turned on, the antenna gain is-13.4dBi, which is 18.4dBi lower than the antenna gain when the diodes are turned off, as Figure 9 shown in the figure.

[0119] When the frequency is 1.561098GHz, the normal working antenna has a normal direction axial ratio of 0.66dB, and has a good circular polarization characteristic. When the horizontal polarization high-power microwave is incident, the horizontal diode is turned on and the vertical diode is turned off, and the normal direction axial ratio is 23.6dB. When the vertical polarization high-power microwave is incident, the horizontal diode is turned off and the vertical diode is turned on, and the normal direction axial ratio is 40dB, as Figure 10 shown in the figure.

[0120] When the frequency is 1.561098GHz, the normal working antenna has a left circular polarization component of-23.5dBi and a right circular polarization component of 5.0dBi, indicating that the antenna polarization is right circular polarization, as Figure 11 shown in the figure. When the horizontal polarization high-power microwave is incident, the horizontal direction diode is turned on and the vertical direction diode is turned off, and the antenna horizontal polarization component is-19.6dBi and the vertical polarization component is 4.0dBi, indicating that the antenna is vertically polarized, as Figure 12 shown in the figure. When the vertical polarization high-power microwave is incident, the horizontal direction diode is turned off and the vertical direction diode is turned on, and the antenna horizontal polarization component is 3.1dBi and the vertical polarization component is-20.9dBi, indicating that the antenna is horizontally polarized, as Figure 13 shown in the figure.

[0121] Through the above setting, a four-feed circularly polarized antenna is selected for design, which proves that the designed protection topology structure can independently suppress the two orthogonal degenerate modes of the circularly polarized antenna, and has good protection effect on the four-feed circularly polarized antenna, and has good universality. Compared with the prior art, the circularly polarized antenna of the present application can realize the protection of the incident high-power microwave from the polarization dimension, and has the function of receiving and transmitting the cross-polarized signal of the incident high-power microwave, which solves the problem of compatibility of strong electromagnetic protection and signal receiving and transmitting function.

[0122] The above is only an embodiment of the present application, and does not limit the present application. Any person skilled in the art can make many possible changes, modifications or modifications to the technical solutions of the present application without departing from the scope of the technical solutions of the present application, and the equivalent embodiments of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application shall fall within the scope of protection of the present application.

Claims

1. A polarization-selective electromagnetically protected circularly polarized antenna, characterized in that, include: The antenna radiating element includes a main radiator (1) and multiple current-coupled perturbation structures (2) disposed on the main radiator (1). The polarization control and protection unit includes at least two sets of protection structures (3) and corresponding control elements; the two sets of protection structures (3) are respectively arranged in two orthogonal polarization directions of the antenna and are selectively connected to the main radiator (1) through the control elements; A multi-feed network, comprising multiple feeders connected with a preset phase difference relationship, is used to excite the antenna radiating element to generate circularly polarized radiation waves. in, Under normal operating conditions, the control element is in the first state, which disconnects the protective structure (3) from the main radiator (1) or makes a high impedance connection, so that the antenna maintains normal circular polarization radiation characteristics. In electromagnetic protection mode, when an incident electromagnetic wave of a specific polarization is sensed, a set of control elements corresponding to the polarization direction switches to the second state, so that the corresponding protection structure (3) is connected to the main radiator (1), thereby changing the radiation impedance of the polarization direction, so that the antenna switches from circular polarization working mode to linear polarization working mode, so as to suppress the incident electromagnetic wave of a specific polarization, while maintaining the ability to receive cross-polarized signals. When a high-power microwave attack with unknown polarization characteristics or composite polarization is detected, all control elements are switched to the second state, so that all protective structures (3) are connected to the main radiator (1), and the antenna enters the total reflection state, thus achieving comprehensive protection against incident waves of arbitrary polarization. The current-coupled perturbation structure (2) is a metal structure that is non-contactly coupled to the main radiator (1) and is arranged in a rotationally symmetrical manner at the corner of the main radiator (1) to excite additional degenerate modes in the main radiator (1) to compensate for the deterioration of the circular polarization axial ratio performance caused by the loading of the protective structure (3). The current-coupled perturbation structure (2) is an L-shaped metal patch, which is set at the four diagonal positions of the main radiator (1).

2. The polarization-selective electromagnetically protected circularly polarized antenna as described in claim 1, characterized in that, The polarization control and protection unit includes four sets of protection structures (3) and four control elements; Four sets of protective structures (3) are symmetrically arranged at the top, bottom, left and right positions of the main radiator (1). The two sets of protective structures (3) located at the top and bottom positions are connected to the main radiator (1) through two control elements to form a vertical polarization control branch. The two sets of protective structures (3) located at the left and right positions are connected to the main radiator (1) through the other two control elements to form a horizontal polarization control branch. The control element is a switching diode.

3. The polarization-selective electromagnetically protected circularly polarized antenna as described in claim 1, characterized in that, The protective structure (3) is a metal patch structure, which is switchably connected to the main radiator (1) through a control element. When the corresponding control element is turned on, the protective structure (3) acts as a parasitic unit of the main radiator (1), changing the current distribution in the corresponding polarization direction, thereby causing impedance mismatch in the polarization direction.

4. The polarization-selective electromagnetically protected circularly polarized antenna as described in any one of claims 1-3, characterized in that, The multi-feed network is a one-to-four feeder network (13), which includes one input port (9) and four output feeders; The four output feeds are connected in a spatially symmetrical manner to the four feed positions (4) around the center of the main radiator (1); Furthermore, the path length from the input port (9) to the four output feeds increases sequentially, so that the RF signals output by the four feeds have a phase difference of 90° sequentially, in order to satisfy the feeding conditions for the antenna to generate circularly polarized radiation.

5. The polarization-selective electromagnetically protected circularly polarized antenna as described in any one of claims 1-3, characterized in that, The antenna radiating element, polarization control and protection element, and multi-feed network are integrated on a double-layer dielectric substrate structure; The dual-layer dielectric substrate structure includes an upper dielectric substrate (10), a metal ground plane (14), and a lower dielectric substrate (11) arranged sequentially from top to bottom. Among them, the main radiator (1) and the current-coupled perturbation structure (2) are disposed on the upper surface of the upper dielectric substrate (10); A multi-feed network is disposed on the lower surface of the lower dielectric substrate (11).

6. The polarization-selective electromagnetically protected circularly polarized antenna as described in claim 5, characterized in that, It also includes a coaxial probe (12), which is connected to the input port (9) of the multi-feed network. An isolation hole is provided on the metal floor (14), and the output power of the multi-feed network passes through the lower dielectric substrate (11), the isolation hole and the upper dielectric substrate (10) in sequence to connect with the main radiator (1).

7. The polarization-selective electromagnetically protected circularly polarized antenna as described in claim 5, characterized in that the upper layer... The dielectric constant of the dielectric substrate (10) is between 9 and 10, and the loss tangent is not greater than 0.002; the dielectric constant of the lower dielectric substrate (11) is between 4 and 5, and the loss tangent is not greater than 0.

002.

8. A method of using a polarization-selective electromagnetically protected circularly polarized antenna as described in any one of claims 1-7, characterized in that, Includes the following steps: Normal signal transmission and reception steps: Control all control elements to the first state, so that all protective structures (3) are disconnected from the main radiator (1) or connected with high impedance. At this time, the antenna works in circular polarization mode to receive and transmit signals normally. Polarization Selective Protection Procedure: When a high-power microwave attack is detected, perform one of the following sub-steps: If the high-power microwave is horizontally polarized, the control element corresponding to the horizontal polarization direction is switched to the second state, so that the corresponding protective structure (3) is connected to the main radiator (1), thereby suppressing the radiation of the antenna in the horizontal polarization mode and forcing the antenna to work in the vertical polarization mode to protect against horizontal polarization attacks and maintain the ability to receive vertical polarization signals. If the high-power microwave is vertically polarized, the control element corresponding to the vertical polarization direction is switched to the second state, so that the corresponding protective structure (3) is connected to the main radiator (1), thereby suppressing the radiation of the antenna in the vertical polarization mode and forcing the antenna to work in the horizontal polarization mode to protect against vertical polarization attacks and maintain the ability to receive horizontal polarization signals. When a high-power microwave attack with unknown polarization characteristics or composite polarization is detected, all control elements are switched to the second state, so that all protective structures (3) are connected to the main radiator (1), and the antenna enters the total reflection state, thus achieving comprehensive protection against incident waves of arbitrary polarization.

Images