A radar system and design method for orthogonal circular polarization high-efficiency transceiver isolation

Abstract

The application discloses a kind of orthogonal circular polarization high-efficiency transceiver isolation radar systems and design method, belong to radar system technical field.The system, transmitter module is used to the signal to be transmitted is amplified, and is passed to antenna module by transmission waveguide;Receiver module is used to the signal received is amplified processing, while providing overload protection;Antenna module includes the double waveguide ladder diaphragm circular polarizer and horn antenna connected in turn, wherein the double waveguide ladder diaphragm circular polarizer is used to the linear polarized signal sent by transmitter module is converted into circular polarized signal, the horn antenna is used to circular polarized signal is radiated to the specified direction of space, while receiving target scattering signal and feedback to receiver module.The application significantly reduces the loss and risk brought by isolator, improves the aliasing phenomenon of ordinary linear polarization image dihedral angle and trihedral angle, relieves over-bright spot effect, improves image interpretation effect, can adapt to different polarization orientation angle.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of radar systems, and particularly relates to a radar system with orthogonal circular polarization and high-efficiency transceiver isolation and a design method. BACKGROUND

[0002] A radar is a remote sensing device that uses electromagnetic wave emission and reception to detect targets, and is divided into imaging radars and non-imaging radars. In a radar system, a signal link can generally be divided into a transmitting link and a receiving link, and the principle is as shown in Figure 1 In the transmitting link, a digital signal generated by a baseband digital signal processor is subjected to intermediate frequency amplification by an intermediate frequency filter to obtain an intermediate frequency signal, is mixed with a local oscillation frequency by a mixer to obtain a radio frequency signal, is subjected to radio frequency filtering and power amplification, is input to a circulator, and is then fed into an antenna to be radiated into space. In the receiving link, a signal received by the antenna is input to the circulator, is then subjected to low-noise amplification and radio frequency filtering, is input to the mixer to be down-converted to an intermediate frequency signal, and is finally output to the signal processor for processing after being subjected to intermediate frequency filtering and intermediate frequency amplification. In a typical radar system, the same linear polarization mode is usually selected for transmitting signals and receiving signals to obtain signals in the HH or VV polarization mode.

[0003] In order to meet the demand for high transmitting power and achieve high-efficiency transceiver isolation, a high-power circulator is usually used as a key component. As shown in Figure 2 , a signal input into the first port of the circulator is output from the second port but not from the third port. Similarly, a signal input from the second port is guided to the third port, and a signal input from the third port is guided to the first port. The conventional radar system usually uses the same linear polarization mode to obtain signals.

[0004] In order to achieve high transmitting power and high-efficiency transceiver isolation, a high-power circulator is usually used in a radar system. The circulator realizes non-reciprocal transmission based on the gyromagnetic property of a ferrite material, but the performance thereof is limited by the power bearing capacity of the ferrite material, and the manufacturing process of a high-frequency circulator requires extremely high precision, and insufficient process precision will result in high loss. Although there is a study that attempts to improve the power capacity by using a longitudinal standing wave inside the ferrite, the technology is not mature at present and needs additional nitrogen assistance to work.

[0005] Therefore, how to design a radar system with high efficiency and low loss under high power conditions without increasing the complexity of the system and ensuring sensitivity is a technical problem to be solved at present. SUMMARY

[0006] To solve the above technical problems, the application provides a radar system with orthogonal circular polarization high-efficiency transceiver isolation and a design method, adopts a double waveguide stepped diaphragm circular polarizer to replace a traditional high-power isolator, utilizes a left-handed circular polarization transmitting signal and a right-handed circular polarization receiving signal to realize that a horn is shared by transmission and reception.

[0007] To achieve the above object, the application adopts the following technical scheme:

[0008] A radar system with orthogonal circular polarization high-efficiency transceiver isolation comprises a transmitter module, a receiver module and an antenna module.

[0009] The transmitter module is used for power amplifying a signal to be transmitted and transmitting the signal to the antenna module through a transmission waveguide.

[0010] The receiver module is used for amplifying and processing a received signal and providing overload protection.

[0011] The antenna module comprises a double waveguide stepped diaphragm circular polarizer and a high-gain horn antenna connected in sequence, the double waveguide stepped diaphragm circular polarizer is used for converting a linear polarization signal from the transmitter module into a circular polarization signal and completing transceiver isolation through orthogonal polarization, and the high-gain horn antenna is used for radiating the circular polarization signal to a specified direction in space, receiving a target scattering signal and feeding back the target scattering signal to the receiver module.

[0012] On the other hand, the application provides a radar system design method with orthogonal circular polarization high-efficiency transceiver isolation, which is applied to the radar system with orthogonal circular polarization high-efficiency transceiver isolation and comprises the following steps.

[0013] The transmitter module is used for power amplifying a signal to be transmitted and transmitting the signal to the antenna module through a transmission waveguide.

[0014] The double waveguide stepped diaphragm circular polarizer of the antenna module is used for converting a linear polarization signal from the transmitter module into a circular polarization signal and completing transceiver isolation through orthogonal polarization, and the horn antenna is used for radiating the circular polarization signal to a specified direction in space, receiving a target scattering signal and feeding back the target scattering signal to the receiver module.

[0015] The receiver module is used for amplifying and processing a received signal and providing overload protection.

[0016] In a third aspect, the present application provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the aforementioned radar system design method for orthogonal circular polarization high-efficiency transceiver isolation.

[0017] In a fourth aspect, the present application provides a computer-readable storage medium having stored thereon executable instructions that, when executed by a processor, enable the processor to implement the aforementioned radar system design method for orthogonal circular polarization high-efficiency transceiver isolation.

[0018] The present application has the following beneficial effects:

[0019] 1. The radar system of the present application realizes orthogonal circular polarization transceiving (transmits left-handed circularly polarized waves and receives right-handed circularly polarized waves) by adopting a dual-waveguide stepped diaphragm circular polarizer, significantly improves the transceiver isolation (better than 25 dB), and saves at least 1.0 dB of double-pass loss. Compared with the traditional circulator scheme, this design greatly improves the power capacity, effectively protects the receiver, and reduces the risk during high-power transmission. The dual-waveguide stepped diaphragm circular polarizer has a compact structure, is easy to process and does not require complex tuning, significantly improves the reliability and stability of the system, and reduces the high loss and discharge risk caused by insufficient process precision of the circulator.

[0020] 2. The radar system of the present application is not only suitable for a single horn antenna, but also can be extended to reflector antenna and phased array antenna systems. By adjusting the amplitude and phase of the T / R components, the antenna pattern can be flexibly changed, improving the adaptability and flexibility of the system.

[0021] 3. Through analysis of the full-link loss, radar sensitivity, relationship between circular polarization and linear polarization signals, Faraday effect and polarization orientation angle influence, the system stability is significantly improved, which can effectively improve the two-plane angle and three-plane angle aliasing phenomenon in ordinary linear polarization images, relieve the over-bright spot effect, improve the image interpretation effect, and adapt to different polarization orientation angles. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a typical radar system principle block diagram;

[0023] Figure 2 is a ferrite element circulator schematic diagram;

[0024] Figure 3 is a radar system principle diagram of the present application based on orthogonal circular polarization to realize high-efficiency transceiver isolation;

[0025] Figure 4 is a dual-waveguide stepped diaphragm circular polarization isolator schematic diagram;

[0026] Figure 5 The size design drawing of the baffle of the double waveguide stepped diaphragm circular polarization isolator;

[0027] Figure 6 The schematic diagram of the horn antenna;

[0028] Figure 7 The principle diagram of the reflector microwave system adopting the double waveguide stepped diaphragm circular polarization isolator;

[0029] Figure 8 The principle diagram of the phased array radar system adopting the double waveguide stepped diaphragm circular polarization isolator;

[0030] Figure 9 The schematic diagram of the horn unit of the phased array radar system;

[0031] Figure 10 The performance curve of the circular polarization isolator;

[0032] Figure 11 The receiving power curve of the dihedral target in different polarization channels; Wherein (a) is the amplitude curve of the co-polarization varying with the target orientation angle, (b) is the amplitude curve of the cross-polarization varying with the target orientation angle;

[0033] Figure 12 The receiving power curve of the dipole target in different polarization channels; Wherein (a) is the amplitude curve of the co-polarization varying with the target orientation angle, (b) is the amplitude curve of the cross-polarization varying with the target orientation angle;

[0034] Figure 13 The receiving power curve of the cylindrical target in different polarization channels; Wherein (a) is the amplitude curve of the co-polarization varying with the target orientation angle, (b) is the amplitude curve of the cross-polarization varying with the target orientation angle;

[0035] Figure 14 The orthogonal circular polarization and co-circular polarization images of the port area in the embodiment of the application, wherein (a) is the orthogonal circular polarization image, (b) is the co-circular polarization image;

[0036] Figure 15 The orthogonal circular polarization and linear polarization images of the port area in the embodiment of the application, wherein (a) is the orthogonal circular polarization image, (b) is the linear polarization image;

[0037] Figure 16 The different polarization channel images of the sea-crossing bridge in the embodiment of the application, wherein (a) is the HH linear polarization image, (b) is the HV linear polarization image, (c) is the LR circular polarization image, (d) is the LL circular polarization image;

[0038] Figure 17These are magnified images of the cross-sea bridge with different polarization channels in an embodiment of the present invention, where (a) is an HH line polarization image and (b) is an LR circular polarization image. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0040] like Figure 3 The diagram shown is a schematic of a radar system based on orthogonal circular polarization to achieve high-efficiency transmit and receive isolation according to the present invention. It is also divided into a transmit link and a receive link. In the transmit link, the radio frequency signal is amplified by the power amplifier, and the resulting high-power microwave signal enters the dual-waveguide stepped diaphragm circular polarizer through the transmission waveguide. The circular polarization signal generated at the output port of the isolator is radiated out through the antenna.

[0041] In the receiving link, circularly polarized electromagnetic waves, after passing through a dual-waveguide stepped diaphragm circular polarizer, are converted into linearly polarized waves with opposite polarization directions, which are then output from different ports depending on the direction of electric field rotation. Generally, when ground objects receive circularly polarized electromagnetic radiation, the main energy of the echo is concentrated in the opposite polarization direction. For example, when a radar transmits left-hand circularly polarized (LHCP), the energy received from right-hand circularly polarized (RHCP) is much greater than that from left-hand circularly polarized. The right-hand circularly polarized echo received by the receiving antenna passes through the dual-waveguide stepped diaphragm circular polarizer and enters the low-noise amplifier via a discharge tube. Simultaneously, a small amount of left-hand circularly polarized echo received by the receiving antenna is coupled to the power amplifier port after passing through the dual-waveguide stepped diaphragm circular polarizer and is attenuated by the isolator at the power amplifier port.

[0042] In one embodiment, the radar system consists of three main modules: a transmitter module, a receiver module, and an antenna module shared by both.

[0043] In one embodiment, the primary function of the transmitter module is to amplify the transmitted signal and transmit it to the antenna via a transmission waveguide, thereby achieving efficient signal radiation. It includes the following components connected in sequence:

[0044] Power amplifier: Used to achieve high-gain signal amplification.

[0045] Transmission waveguide: Used to efficiently combine the output power and transmit it to the antenna module.

[0046] In one embodiment, the core function of the receiver module is to amplify and process the received signal, while providing overload protection to ensure safe system operation. It includes the following layout:

[0047] Limiter (discharge tube): When the received signal energy is too high, it protects the low-noise amplifier receiver from damage by discharging (i.e., Figure 3 (Limited protection).

[0048] Low Noise Amplifier (LNA): Low noise, high gain amplification of the received signal.

[0049] Receiver: Further processing or storage of the amplified signal, providing data support for subsequent analysis or use.

[0050] In one embodiment, the combination of polarization isolation (25 dB) and limiter provides multi-level overload protection, ensuring safe and stable system operation. Machining and welding, no tuning; simple manufacturing process, reducing the complexity of debugging and maintenance.

[0051] In one embodiment, the antenna module uses a quadrature dual circular polarization transceiver horn scheme instead of a circulator + linear polarization horn scheme, responsible for radiating the amplified signal to the target direction, while receiving the scattered signal from the target and feeding back to the receiver module. It includes the following components:

[0052] Dual waveguide stepped iris circular polarizer, a compact, easy to process, light weight, small volume, high power and large bandwidth circular polarizer. Its feature is to combine the functions of quadrature mode coupler and circular polarizer, which can realize polarization conversion and polarization separation, thus simplifying the structure of the system.

[0053] In one embodiment, the core of the dual waveguide stepped iris circular polarizer is Figure 4 The rectangular waveguide (i.e. Figure 4 The rectangular waveguide section), the partition (i.e. Figure 4 The partition section) and the square waveguide (i.e. Figure 4 The square waveguide section), wherein the first and second ports of the dual waveguide stepped iris circular polarizer are standard rectangular waveguide ports, and the third / fourth ports are square common ports, representing the electromagnetic waves corresponding to the TE 01 and TE 10 modules. When transmitting signals, the TE 10 linearly polarized signal excited from the first port (or the second port) is transmitted through the rectangular waveguide, and by designing a partition with a specific size according to the center frequency, the TE 10 and TE 01 module signal amplitudes are close, and the phase difference is 90 degrees, so as to synthesize left-handed (or right-handed) circularly polarized signals, and the energy is synthesized and output through the square waveguide, so that the signal is converted to an output circularly polarized signal at the third / fourth port after passing through the circular polarization isolator. When receiving signals, the left-handed (or right-handed) circularly polarized signal input from the third / fourth port passes through the designed partition, and the energy is converted to TE 10 linearly polarized signal, which is output from the first port (or the second port). Assuming that the center frequency of the electromagnetic wave is λ, the partition size is designed as Figure 5As shown, a horn antenna radiates immediately after it during operation.

[0054] High-gain horn antennas, such as Figure 6 As shown, it is located immediately after the third port of the dual-waveguide stepped diaphragm circular polarizer and is designed and manufactured as an integral part of the circular polarizer. It is used to further radiate the circularly polarized signal to a specified direction in space, while receiving the target scattered signal and transmitting it to the receiver.

[0055] In one embodiment, such as Figure 7 As shown, the high-gain horn antenna no longer radiates electromagnetic waves directly towards the target but instead acts as a feed element of the transmitting surface to emit waves towards the reflecting surface. Its working principle is similar to... Figure 3 They are basically the same, except that the distribution of the electromagnetic beam in space is further altered by using a reflective surface.

[0056] In one embodiment, such as Figure 8 As shown, multiple orthogonally circularly polarized transceiver horns form an array to radiate electromagnetic waves. The working principle of each orthogonally circularly polarized transceiver horn is as follows: Figure 9 As shown, with Figure 3 The difference is that each of the 1 / 2 ports of the orthogonal circularly polarized transceiver horn is connected to a T / R module. By adjusting the amplitude and phase of the T / R modules, the antenna pattern of the entire array can be changed, thus based on... Figure 3 The principle is extended to form a circularly polarized transceiver phased array, which radiates electromagnetic waves into space through the phased array antenna.

[0057] Replacing the traditional circulator + linearly polarized horn scheme with an orthogonal circular polarization design significantly improves transmit / receive isolation performance, increases transmitter power capacity, and is suitable for high-power applications; it also simplifies system structure and improves reliability. Figure 10 As shown, the port polarization isolation is ≥25 dB. Within the 8.2 GHz to 8.4 GHz frequency band, the S-parameter (scattering parameter) S12 is consistently below -25 dB, effectively protecting the receiving link and reducing signal interference. It receives most of the energy scattered by the target, reducing the effects of Faraday effect and multipath effect, distinguishing dihedral and trihedral scattered energy in high-resolution signals, and mitigating the oversaturation effect.

[0058] The following section provides a theoretical analysis and simulation comparison of the application effects of this invention and traditional solutions.

[0059] The transformation of the scattering matrix S between circular and linear polarization is discussed, considering the changes in the scattering matrix S under different orthogonal coordinate bases. Let there be two sets of orthogonal polarization bases. and polarization base The unitary transformation matrix between the two sets of orthogonal polarization bases is: The scattering matrix S is transferred from the polarization basis. scattering matrix Transformation to polarization base scattering matrix .in, and These are two mutually orthogonal unit vectors, representing two independent polarization directions. Indicates and vertical direction Indicates and The vertical direction.

[0060] Incident wave The transformation relationship between the two coordinate bases is as follows:

[0061] (1)

[0062] in, Indicates polarization base The incident wave, Indicates polarization base The incident wave.

[0063] Scattered waves The transformation relationship between the two coordinate bases is as follows:

[0064] (2)

[0065] in, Indicates polarization base Scattered waves, Indicates polarization base Scattered waves.

[0066] We can obtain:

[0067] (3)

[0068] in, This is the common similarity transformation of the polarization scattering matrix, superscript The superscript T denotes the complex conjugate, and the superscript T denotes the transpose of the matrix.

[0069] Binding linear polarization base and circular polarization base The unitary transformation relationship between them can be used to obtain the transformation relationship between the scattering matrix and the linear polarization basis:

[0070] (4)

[0071] in, and These represent the horizontal polarization direction and the vertical polarization direction, respectively. and Represents the left-hand circular polarization direction and the right-hand circular polarization direction, where j is the imaginary unit; 、 、 、 is the scattering parameter, L and R represent left-handed circular polarization and equivalent right-handed circular polarization, respectively. 、 、 、 is the backscattering coefficient under linear polarization basis, H represents horizontal direction, and V represents vertical direction.

[0072] Generally, right-handed circular vector represents the left-handed circular vector (i.e., left-handed circular polarization direction) orthogonal equivalent polarization basis, that is The polarization total power Span has rotational invariance in the coordinate basis transformation and does not change with the change of the coordinate basis, that is:

[0073] (5)

[0074] For Faraday effect analysis, the Faraday effect describes the polarization rotation phenomenon of light waves when passing through a magnetic field. The rotation angle is related to the wavelength of light, the intensity of the magnetic field, the properties of the medium, and the distance of light propagation in the medium, etc.

[0075] Let the magnetic induction intensity be B, and the path length of light in the substance be d, then the angle of vibration plane rotation is:

[0076] (6)

[0077] where V is the Verdet constant, which is related to the properties of the substance, temperature, and the frequency (wavelength) of light. In a certain substance, whether the light propagates along the magnetic field direction or the inverse magnetic field direction, the vibration plane rotation is the same and is determined only by the magnetic field direction. If the rotation is in a right-handed helical relationship with the magnetic field direction, the V of the substance is taken as positive, that is > 0. In this way, after the light propagates back and forth for the same distance, the rotation angle of the vibration plane is equal to twice the single-pass rotation angle. This is the difference between magnetic rotation and natural rotation (in the case of natural rotation, the vibration plane returns to the original position after propagating back and forth for the same distance).

[0078] The influence of wavelength mainly manifests in the Faraday rotation constant, because this constant is related to the properties of the material, and the response of the material to electromagnetic waves of different wavelengths is different. This means that under the same conditions, light waves with shorter wavelengths may produce smaller polarization rotation, while light waves with longer wavelengths may produce larger polarization rotation. Therefore, for high-frequency SAR systems, the Faraday effect will cause a small vibration deflection of linearly polarized waves; for circularly polarized waves, the vibration direction deflection under H polarization and V polarization is the same angle, and after combination, it is still a circularly polarized wave, only the overall phase changes, so it is less affected.

[0079] For different target scattering energy comparison, according to the conversion relationship of linear polarization and circular polarization, the following can be obtained:

[0080] (7)

[0081] Wherein, E H represents the electric field intensity of the horizontal polarization component, E V represents the electric field intensity of the vertical polarization component,

[0082] E L represents the electric field intensity of the left circular polarization component, E R represents the electric field intensity of the right circular polarization component.

[0083] Considering the circular polarization axial ratio The observation matrix under the double circular polarization base The relationship between the linear polarization scattering matrix Is as follows:

[0084] (8)

[0085] According to the research results of Cameron et al., in high-resolution SAR images, the scattering of complex targets can be decomposed into the scattering of simple structure scatterers such as dihedral angle, trihedral angle (sphere, flat plate), dipole (linear body), cylinder, narrow dihedral angle, left-handed helix, right-handed helix, Wave oscillator, etc. The circular polarization SAR scattering characteristics of typical structure units such as dihedral angle, trihedral angle (sphere, flat plate), dipole (linear body), and cylinder are analyzed.

[0086] The polarization scattering characteristics of the target are related to the shape, structure, and material of the target, and are also related to the attitude of the target relative to the radar line of sight. For the target rotating around the radar wave incident direction in the plane perpendicular to the radar line of sight, the rotation angle is called the orientation angle. When the above formula is the orientation angle , the linear polarization scattering matrix of the target is: When the orientation angle is , the linear polarization scattering matrix of the target is:

[0087] (9)

[0088] The rotation scattering matrix of different targets is as follows:

[0089] Tetrahedron:

[0090] (10)

[0091] Dihedral angle:

[0092] (11)

[0093] dipole:

[0094] (12)

[0095] cylinder:

[0096] (13)

[0097] The electric field vector of linear polarization wave changes in a fixed direction perpendicular to the radar line of sight with time, while the electric field vector of circular polarization wave presents left-handed or right-handed change on a circle around the radar line of sight with time, and different polarized scattering characteristics will be presented for linear polarization and circular polarization radar targets. The elliptical polarization scattering matrix of the targets can be obtained by substituting the linear polarization scattering matrix of the triangular pyramid, dihedral, dipole and cylinder into the above formula, as shown below:

[0098] triangular pyramid:

[0099] (14)

[0100] dihedral:

[0101] (15)

[0102] dipole:

[0103] (16)

[0104] cylinder:

[0105] (17)

[0106] When the circular polarization axial ratio is less than 1, the amplitude (absolute value) of each polarization complex scattering amplitude in the elliptical polarization scattering matrix of the dihedral, dipole and cylinder changes with the target orientation angle and axial ratio, Figures 11-13 the curves of the amplitude (absolute value) of each polarization complex scattering amplitude in the elliptical polarization scattering matrix of the dihedral, dipole and cylinder changing with the target orientation angle and axial ratio are respectively given, wherein Figures 11-13 (a) of the dihedral, dipole and cylinder are respectively the curves of the co-polarization amplitude changing with the target orientation angle, Figures 11-13The maximum value of the amplitude of each polarization complex scattering amplitude in the three target elliptical polarization scattering matrices appears at the 45° orientation angle, and when the axial ratio is greater than 0.7, the maximum value of the amplitude of the dihedral cross-polarization complex scattering amplitude is less than 0.26, and the maximum value of the amplitude of each polarization complex scattering amplitude of other targets is less than 0.05, which has little effect.

[0107] The simulation analysis has the following conclusions:

[0108] For the plane, sphere, and trihedral corner targets, the energy received by the LR transceiving mode is equivalent to that by the HH transceiving mode, and is much greater than that by the LL transceiving mode.

[0109] For the dihedral corner target, the energy received by the LL transceiving mode is equivalent to that by the HH transceiving mode, and is much greater than that by the LR transceiving mode.

[0110] For the dipole target, when the polarization orientation angle is greater than 45°, the received power of the LR transceiving mode is greater than that of the HH transceiving mode.

[0111] For the cylindrical target, when the polarization orientation angle is greater than 45°, the received power of the LR transceiving mode is greater than that of the HH transceiving mode, and the received power of the LR transceiving mode is greater than that of the LL transceiving mode.

[0112] Embodiment:

[0113] In the field of satellite-to-ground communication, circular polarization is widely used for receiving and transmitting due to its many advantages, including: suppressing rain and fog interference and resisting multipath reflection, and the ionosphere Faraday rotation effect has less impact, and it can also eliminate the polarization vector mismatch caused by the change of the slant angle between the satellite and each station on the ground. In the field of radar, circular polarization has also been widely used in the sub-field of Synthetic Aperture Radar (SAR). One of the advantages of using circular polarization on SAR is that it has higher target classification performance than linear polarization in dual-polarization mode. In addition, circular polarization SAR is less affected by multipath signal interference and polarization mismatch loss caused by mismatch of antenna polarization direction.

[0114] The following uses Lutan-1 satellite-borne SAR port and bridge area real-time data to simulate and verify the circular polarization receiving and transmitting.

[0115] The L-band SAR images under different polarization transceiving modes are compared and analyzed as follows Figure 14are shown, where (a) is the cross-circular polarization image, (b) is the co-circular polarization image; first, the contrast chart of the right-hand circularly polarized received power and the left-hand circularly polarized received power is given under the condition of radar left-hand circularly polarized transmission, which corresponds to the LR and LL transceiving modes respectively. The same dynamic range is used for display in the two charts, and it can be seen from the chart that the LR transceiving mode and the LL transceiving mode have equivalent power, the LL power is higher in the dihedral angle gathering area, and the LR power is higher in the plane area.

[0116] Next Figure 15 the contrast chart of the LR and HH transceiving modes is given, where Figure 15 (a) is the cross-circular polarization image, Figure 15 (b) is the linear polarization image. In the LR transceiving mode, the received power is slightly lower than that in the HH transceiving mode, and compared with the HH transceiving mode, the LR transceiving mode can reduce the dihedral angle scattering strong points to a certain extent, and the sidelobe is improved.

[0117] The images near the cross-sea bridge are compared as Figure 16 shown, where Figure 16 (a) is the HH linear polarization image, Figure 16 (b) is the HV linear polarization image, Figure 16 (c) is the LR circular polarization image, and (d) is the LL circular polarization image; it can be seen that there are many dense scattering strong points under the HH linear polarization, and it is difficult to distinguish the bridge structure, the HV linear polarization received power is small, and the LR and LL transceiving modes can distinguish the scattering power corresponding to the dihedral angle and the trihedral angle, which is more conducive to the discrimination of the fine structure of the target.

[0118] Further magnify the local part of the cross-sea bridge as Figure 17 shown, where Figure 17 (a) is the HH linear polarization image, Figure 17 (b) is the LR circular polarization image. By comparing the images of the HH polarization channel and the LR polarization channel, it can be seen that the HH channel appears strong aliasing, and it is difficult to distinguish the features, while the image of the LR polarization channel is relatively clear.

[0119] In summary, the application adopts a double waveguide stepped diaphragm circular polarizer to replace a high-power isolator composed of a microwave ferrite. Compared with a series of problems caused by ferrite absorption in a traditional high-power isolator, the double waveguide stepped diaphragm circular polarizer is mainly realized by a waveguide, has the advantages of compact structure, easy processing, light weight, small size, and the upper limit of the power capacity of the double waveguide stepped diaphragm circular polarizer will be mainly determined by the micro-discharge effect of the waveguide, the insertion loss is smaller than that of the traditional isolator, the transmit-receive isolation degree is improved, and the receiver is protected during high-power transmission. By omitting the high-power circulator, the discharge risk caused by the process precision is reduced, the system loss is reduced, the system heat dissipation demand is reduced, and the system stability is improved. For application scenarios requiring high resolution and high signal-to-noise ratio, the application can make more electromagnetic wave power actually reach the antenna and be radiated out, so that the detection distance and detection precision of the radar system are improved. By separating the scattering energy of the dihedral and trihedral angles through orthogonal circular polarization, the over-bright point effect is alleviated, and the signal interpretation effect is improved.

[0120] In another aspect, the application provides a radar system design method for realizing high-efficiency transmit-receive isolation based on orthogonal circular polarization, applied to the radar system for realizing high-efficiency transmit-receive isolation based on orthogonal circular polarization, comprising:

[0121] The transmitter module amplifies the to-be-transmitted signal and transmits the to-be-transmitted signal to the antenna module through a transmission waveguide;

[0122] The double waveguide stepped diaphragm circular polarizer of the antenna module converts the linear polarized signal from the transmitter module into a circular polarized signal, and the horn antenna radiates the circular polarized signal to a specified direction in space, while receiving a target scattering signal and feeding back the target scattering signal to the receiver module;

[0123] The receiver module amplifies the received signal and provides overload protection.

[0124] In a third aspect, the application provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; wherein when the one or more programs are executed by the one or more processors, the one or more processors realize the radar system design method for realizing high-efficiency transmit-receive isolation based on orthogonal circular polarization.

[0125] In a fourth aspect, the application provides a computer-readable storage medium having executable instructions stored thereon, which can make the processor realize the radar system design method for realizing high-efficiency transmit-receive isolation based on orthogonal circular polarization when the instructions are executed by the processor.

[0126] Those skilled in the art will appreciate that embodiments of the present application can be readily used as software, hardware, or a combination of software and hardware. In a software embodiment, the methods can be tangibly embodied in a machine-readable storage medium having stored thereon instructions that can be used to program a computer to perform any of the methods. The software implementation can be initialized by loading and executing a set of instructions arranged to perform one of the methods into the computer's memory. Alternatively, hard-wired circuitry can be used in place of, or in combination with, software instructions. Thus, the

[0127] The present application is described in reference to the flowchart and / or block diagrams of the methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each block of the flowchart and / or block diagrams, and combinations of blocks in the flowchart and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart and / or block diagram block or blocks. Figure 1 Figure 1

[0128] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the flowchart and / or block diagram block or blocks. Figure 1 Figure 1

[0129] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the flowchart and / or block diagram block or blocks. Figure 1 Figure 1

[0130] While preferred embodiments of the application have been described, additional variations and modifications can be made to these embodiments by those skilled in the art once they have the benefit of the foregoing description. Therefore, the appended claims are intended to cover all such variations and modifications as falling within the scope of the application. ​​​​​​

[0131] It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

Claims

1. A radar system with high efficiency and transceiver isolation of orthogonal circular polarization, transceiver isolation is realized by orthogonal circular polarization, without using circulator or ferrite isolation device, characterized in that, The transmitter module, the receiver module and the antenna module are included. The transmitter module is used for power amplification of the to-be-transmitted signal and transmission to the antenna module through a transmission waveguide. The receiver module is used for amplification processing of the received signal and provides overload protection. The antenna module includes a double waveguide stepped diaphragm circular polarizer and a high-gain horn antenna connected in sequence. The double waveguide stepped diaphragm circular polarizer is used for conversion of linear polarization signals from the transmitter module into circular polarization signals and completion of transceiver isolation through orthogonal polarization, including left-handed circular polarization transmission and right-handed circular polarization reception.

2. The radar system of claim 1, wherein, The high-gain horn antenna is used for radiation of the circular polarization signals to a specified direction in space, reception of target scattering signals and feedback to the receiver module, and realization of a shared horn antenna for transmission and reception.

3. The radar system of claim 1, wherein, The double waveguide stepped diaphragm circular polarizer includes a rectangular waveguide, a partition and a square waveguide. The partition has a multi-stage stepped structure and is used for decomposition of input TE10 mode linear polarization signals into two orthogonal TE10 modes and TE01 modes, thereby forming left-handed or right-handed circular polarization signals.

4. The radar system of claim 1, wherein, The rectangular waveguide includes a first port and a second port, the square waveguide includes a third common port and a fourth common port, and when a signal is transmitted, TE 10 The mode linear polarization signal is transmitted through the rectangular waveguide, and the TE 10 mode and TE 01 The mode signal amplitude is close, and the phase difference is 90 degrees, and the left-handed circular polarization signal or the right-handed circular polarization signal is synthesized, and the energy is synthesized and output through the square waveguide; the horn antenna is connected behind the third common port and the fourth common port of the circular polarizer.

5. The radar system of claim 1, wherein, The transmitter module includes a power amplifier and a transmission waveguide connected in sequence.

6. The radar system of claim 1, wherein, The power amplifier is used for amplification of the to-be-transmitted signal.

7. The radar system of claim 6, wherein, The transmission waveguide is used for efficient synthesis and transmission of the output power of the amplified to-be-transmitted signal to the antenna module.

8. A radar system design method of orthogonal circular polarization high-efficiency transceiver isolation, applied to the radar system of orthogonal circular polarization high-efficiency transceiver isolation according to any one of claims 1-7, characterized in that, The receiver module includes a limiter, a low-noise amplifier and a receiver. The low-noise amplifier is used for low-noise and high-gain amplification of the received signal. The limiter is used for protection of the low-noise amplifier receiver from damage through discharge. The receiver is used for processing or storage of the amplified received signal.

9. An electronic device, comprising: A reflecting surface is further included. The high-gain horn antenna serves as a feed element of a transmitting surface and emits to the reflecting surface. The antenna module includes a plurality of horn antennas for electromagnetic wave radiation in an array form and constitutes a circular polarization transceiving phased array. A first port and a second port of each horn antenna of the plurality of horn antennas are respectively connected to a T / R component.

10. A computer-readable storage medium, characterized in that, The amplitude and phase of the T / R component are adjusted to change the antenna pattern of the entire array. The transmitter module is used for power amplification of the to-be-transmitted signal and transmission to the antenna module through a transmission waveguide. The double waveguide stepped diaphragm circular polarizer of the antenna module converts linear polarization signals from the transmitter module into circular polarization signals and completes transceiver isolation through orthogonal polarization. The horn antenna radiates the circular polarization signals to a specified direction in space, receives target scattering signals and feeds back to the receiver module. The receiver module amplifies the received signal and provides overload protection. One or more processors are included. A memory is used for storage of one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement the radar system design method with orthogonal circular polarization and high-efficiency transceiver isolation. Executable instructions are stored on the memory and executed by the processor to implement the radar system design method with orthogonal circular polarization and high-efficiency transceiver isolation.

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