SAR (Synthetic Aperture Radar) two-dimensional multiphase segmented modulation interference method based on time modulation metasurface

Abstract

The invention discloses an SAR (Synthetic Aperture Radar) two-dimensional multi-phase segmented modulation interference method based on a time modulation metasurface, and relates to the technical field of signal processing. Each metasurface unit is combined with a variable capacitance diode through two metal square rings with opposite and symmetrical openings; according to the metasurface, the phase, the amplitude and the polarization state of incident electromagnetic waves are flexibly regulated and controlled, the response of the metasurface to the electromagnetic waves can be adjusted in real time according to the requirements of different application scenes through the dynamic regulation and control capacity, and therefore the accurate control over the electromagnetic environment is achieved; according to the structure of the time modulation metasurface, flexible regulation and control of the phase, the amplitude and the polarization state of incident electromagnetic waves and accurate control of the electromagnetic environment can be achieved only by using the two metal square rings with opposite and symmetrical openings and the variable capacitance diode, and compared with a traditional complex time modulation metasurface, the modulation performance of the time modulation metasurface is greatly improved, and the time modulation metasurface is suitable for large-scale popularization and application. And high-precision SAR radar interference is realized.

Description

Technical Field

[0001] The present invention relates to the field of signal processing technology, and in particular to a SAR two-dimensional multi-phase segmented modulation interference method, device, equipment and medium based on a time-modulated metasurface. Background Art

[0002] Synthetic Aperture Radar (SAR) is a high-resolution imaging radar that has the characteristics of all-day, all-weather and long-range, and has indisputable advantages in military reconnaissance applications. In order to cope with the potential threat of enemy SAR reconnaissance systems in modern electronic warfare, interference methods for SAR imaging have received widespread attention in order to effectively hide important characteristic information of high-value targets.

[0003] Traditional SAR jamming methods can be divided into active jamming and passive jamming. Active jamming uses an active jammer to transmit jamming signals to the SAR system. This method generally requires high-power jammers and sensors, which is costly and has the risk of exposing the target area. Passive jamming methods do not actively emit electromagnetic signals, but instead use passive devices such as corner reflectors and foils to generate strong echo signals of false targets, interfering with SAR reconnaissance of the protected target. However, these passive devices lack flexibility and their jamming effects are limited.

[0004] With the rapid development of electromagnetic metasurface technology, time-modulated metasurfaces have the ability to flexibly modulate the amplitude, phase, frequency and other characteristics of incident electromagnetic waves in real time. Therefore, using metasurface technology to modulate incident electromagnetic waves has become a development trend. At present, time-modulated metasurfaces generally include voltage-modulated metasurfaces, light-modulated metasurfaces and temperature-modulated metasurfaces. Voltage-modulated metasurfaces generally regulate their electromagnetic properties by changing the voltage applied to the metasurface unit. Light-modulated metasurfaces utilize the photoelectric effect of photosensitive materials (such as photoconductive materials, optoelectronic materials, etc.) to regulate the electromagnetic properties of the metasurface by changing the light intensity or wavelength. Temperature-modulated metasurfaces utilize the thermal expansion and contraction effect or thermosensitive effect of materials to regulate the electromagnetic properties of the metasurface by changing the temperature. However, such time-modulated metasurfaces generally require the design of relatively complex structures to continuously modulate the various characteristics of the time-modulated metasurface in the process of modulating electromagnetic waves, which reduces the modulation performance and makes it difficult to achieve high-precision SAR radar interference. Summary of the invention

[0005] The embodiment of the present invention provides a SAR two-dimensional multi-phase segmented modulation interference method based on a time-modulated metasurface, which can solve the problem in the prior art that the current time-modulated metasurface usually needs to design a relatively complex structure to continuously modulate various characteristics of the time-modulated metasurface in the process of modulating electromagnetic waves, thereby reducing the modulation performance of the modulation and making it difficult to achieve high-precision SAR radar interference.

[0006] The embodiment of the present invention provides a SAR two-dimensional multi-phase segmented modulation interference method based on a time modulation metasurface, comprising the following steps:

[0007] Designing a time-modulated metasurface and installing it on the surface of a protected target; the time-modulated metasurface is composed of a plurality of periodically arranged metasurface units;

[0008] The metasurface unit comprises a first substrate, the top surface of which is provided with two metal square rings with openings arranged in opposite directions and symmetrically, and a varactor diode is provided between the two metal square rings; the metal square rings are used to adjust the phase, amplitude and polarization state of the electromagnetic wave incident on the metasurface unit, and to reflect or transmit the electromagnetic wave;

[0009] By changing the voltage applied to the two metal square rings, the voltage on both sides of the varactor diode is changed, and the equivalent capacitance of the varactor diode is adjusted in real time to adjust the phase of the electromagnetic wave incident on the metasurface unit to a continuous change;

[0010] The time-modulated metasurface receives the transmission signal of the SAR radar, performs two-dimensional intra-pulse and inter-pulse multi-phase segmented modulation and reflection on the transmission signal, and deceives and interferes with the SAR radar through the reflected signal.

[0011] Preferably, a metal grounding plate is disposed on the bottom surface of the first substrate, a second substrate is disposed on the bottom surface of the metal grounding plate, two bias lines are disposed on the bottom surface of the second substrate, and the two bias lines are respectively connected to corresponding metal square rings through two metal vias disposed on the first substrate;

[0012] The metal grounding plate is located on the bottom surface of the first substrate and is used for electromagnetic shielding and grounding, while preventing electromagnetic waves from leaking and interfering inside the metasurface unit;

[0013] The bias line is located on the bottom surface of the second substrate and is used to provide a DC voltage or current to the metal square ring to change the capacitance value of the variable capacitance diode to dynamically control the regulation of the metasurface electromagnetic wave.

[0014] Preferably, the two-dimensional intra-pulse and inter-pulse multi-phase segmented modulation of the transmission signal comprises:

[0015] When the transmission signal of the SAR radar is incident on the time-modulated metasurface, the voltage on both sides of the varactor diode is changed by changing the voltage applied on the two bias lines, so as to adjust the equivalent capacitance of the varactor diode in real time, and the phase of the electromagnetic wave signal incident on the time-modulated metasurface is respectively subjected to two-dimensional intra-pulse multi-phase segmented modulation and slow-time two-dimensional inter-pulse multi-phase segmented modulation, and the intra-pulse multi-phase segmented modulation signal and the inter-pulse multi-phase segmented modulation signal are respectively obtained;

[0016] The intra-pulse multi-phase segmented modulation signal and the inter-pulse multi-phase segmented modulation signal are respectively:

[0017]

[0018] in: represents the multi-phase segmented modulation signal within the pulse; p2(t m ) represents the pulse-to-pulse multi-phase segmented modulation signal; * represents the convolution operation; τ1,T1,f1=1 / T1,φ p1 , P1, N1 represent the segment duration, modulation period, modulation frequency, modulation phase, number of phase segments within the pulse, and number of repetitions of the intra-pulse multi-phase segment modulation signal respectively; τ2, T2, f2 = 1 / T2, φ p2 , P2, N2 represent the segment duration, modulation period, modulation frequency, modulation phase, number of segmentation between pulses, and number of repetitions of the inter-pulse multi-phase segmented modulation signal respectively;

[0019] The two-dimensional multi-phase segmented modulation signal is:

[0020]

[0021] Where: t m Indicates slow time; Represents a two-dimensional multi-phase segmented modulation signal.

[0022] Preferably, the forming of the reflection signal comprises:

[0023] The time modulation metasurface on the stationary target receives the transmission signal of the SAR radar, and performs two-dimensional intra-pulse multi-phase segmented modulation and slow-time two-dimensional inter-pulse multi-phase segmented modulation on the transmission signal, obtains the intra-pulse multi-phase segmented modulation signal and the inter-pulse multi-phase segmented modulation signal, and forms a two-dimensional multi-phase segmented modulation signal;

[0024] The spectrum of the two-dimensional multi-phase segmented modulation signal in the frequency domain is extracted, and the spectrum of the two-dimensional multi-phase segmented modulation signal is subjected to multiple periodic weighted expansions in the range and azimuth directions of the protected target, and the spectrum of the two-dimensional multi-phase segmented modulation signal is replaced with multiple different spectrums generated in the range and azimuth directions in sequence, respectively, to form multiple harmonic components of the two-dimensional multi-phase segmented modulation signal in the range and azimuth directions, and the multiple harmonic components in the range and azimuth directions are synthesized into a two-dimensional multi-phase segmented interference signal, and the two-dimensional multi-phase segmented interference signal is a reflected signal.

[0025] Preferably, the two-dimensional multi-phase segmented interference signal is:

[0026]

[0027] Wherein: f1 represents the modulation frequency of the intra-pulse multi-phase segmented modulation signal; f2 represents the modulation frequency of the inter-pulse multi-phase segmented modulation signal.

[0028] Preferably, the deceptive interference to the SAR radar includes:

[0029] The SAR radar receives the two-dimensional multi-phase segmented interference signal, and performs range matching filtering, range migration correction and clutter suppression on the interference signal, forming a false target array along the range and azimuth of the protected target in the interference image, thereby achieving interference to the SAR radar;

[0030] The offsets of the mnth false target in the distance dimension and the azimuth dimension are:

[0031]

[0032] Wherein: f1 represents the modulation frequency of the multi-phase segmented modulation signal within a pulse; f2 represents the modulation frequency of the multi-phase segmented modulation signal between pulses; γ represents the Doppler modulation frequency in the distance direction; μ represents the Doppler modulation frequency in the azimuth direction; λ represents the wavelength; and c represents the speed of light.

[0033] The embodiment of the present invention also provides a SAR two-dimensional multi-phase segmented modulation interference device based on a time modulation metasurface, comprising:

[0034] A design module is used to design a time-modulated metasurface and install it on the surface of the protection target; the time-modulated metasurface is composed of a plurality of periodically arranged metasurface units;

[0035] The metasurface unit comprises a first substrate, the top surface of which is provided with two metal square rings with openings arranged in opposite directions and symmetrically, and a varactor diode is provided between the two metal square rings; the metal square rings are used to adjust the phase, amplitude and polarization state of the electromagnetic wave incident on the metasurface unit, and to reflect or transmit the electromagnetic wave;

[0036] By changing the voltage applied to the two metal square rings, the voltage on both sides of the varactor diode is changed, and the equivalent capacitance of the varactor diode is adjusted in real time to adjust the phase of the electromagnetic wave incident on the metasurface unit to a continuous change;

[0037] SAR radar jammer module, the time-modulated metasurface receives the transmission signal of the SAR radar, performs two-dimensional intra-pulse and inter-pulse multi-phase segmented modulation and reflection on the transmission signal, and deceives and jams the SAR radar through the reflected signal.

[0038] An embodiment of the present invention further provides an electronic device, including a memory and a processor;

[0039] The memory is used to store computer programs;

[0040] The processor is used to implement the steps of the SAR two-dimensional multi-phase segmented modulation interference method based on time-modulated metasurface as described above when executing the computer program stored in the memory.

[0041] An embodiment of the present invention also provides a computer-readable storage medium, characterized in that it is used to store a computer program, and when the computer program is executed by a processor, the steps of the SAR two-dimensional multi-phase segmented modulation interference method based on time-modulated metasurface as described above are implemented.

[0042] The embodiment of the present invention provides a SAR two-dimensional multi-phase segmented modulation jamming method based on a time-modulated metasurface. Compared with the prior art, the method has the following beneficial effects:

[0043] Each metasurface unit in the present invention realizes flexible regulation of the phase, amplitude and polarization state of the incident electromagnetic wave through the combination of two metal square rings with opposite and symmetrical openings and a varactor diode. This dynamic regulation capability enables the metasurface to adjust its response to electromagnetic waves in real time according to the needs of different application scenarios, thereby realizing precise control of the electromagnetic environment. The structure of the present invention only uses two metal square rings with opposite and symmetrical openings and a varactor diode to realize flexible regulation of the phase, amplitude and polarization state of the incident electromagnetic wave, as well as precise control of the electromagnetic environment. Compared with traditional complex time-modulation metasurfaces, the modulation performance of the time-modulation metasurface is greatly improved, and high-precision SAR radar interference is achieved.

[0044] Moreover, when the time-modulated metasurface receives the transmission signal of the SAR radar, it can perform two-dimensional intra-pulse and inter-pulse multi-phase segmented modulation on the signal and reflect back the modulated signal. This carefully designed reflected signal can simulate a radar image that is different from the real target, thereby causing deceptive interference to the SAR radar, which can effectively reduce the radar's detection and identification capabilities of the target and protect the target from radar threats. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A schematic diagram of the overall process of a SAR two-dimensional multi-phase segmented modulation interference method based on a time-modulated metasurface provided in an embodiment of the present invention;

[0046] Figure 2 A schematic diagram of an interference model of a SAR two-dimensional multi-phase segmented modulation interference method based on a time-modulated metasurface provided in an embodiment of the present invention;

[0047] Figure 3 A schematic diagram of the design of a time-modulated metasurface for a SAR two-dimensional multi-phase segmented modulation interference method based on a time-modulated metasurface provided in an embodiment of the present invention;

[0048] Figure 4 A schematic diagram of the original SAR imaging result without interference using the SAR two-dimensional multi-phase segmented modulation interference method based on the time-modulated metasurface provided in an embodiment of the present invention;

[0049] Figure 5 A schematic diagram of intra-pulse modulation phase distribution of a SAR two-dimensional multi-phase segmented modulation interference method based on a time-modulated metasurface provided in an embodiment of the present invention;

[0050] Figure 6 A schematic diagram of the inter-pulse modulation phase distribution of the SAR two-dimensional multi-phase segmented modulation interference method based on the time modulation metasurface provided in an embodiment of the present invention;

[0051] Figure 7 A schematic diagram of interference imaging results of a SAR two-dimensional multi-phase segmented modulation interference method based on a time-modulated metasurface provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0053] See also Figure 1 The embodiment of the present invention provides a SAR two-dimensional multi-phase segmented modulation interference method based on a time-modulated metasurface, comprising the following steps:

[0054] Step 1: Construction of SAR imaging interference model based on time-modulated metasurface.

[0055] Step 2: Design of time-modulated metasurface.

[0056] Step 3: Establishment and generation of a two-dimensional multi-phase segmented modulation signal model based on the time-modulated metasurface.

[0057] Step 4: SAR imaging processing and imaging interference effect analysis.

[0058] The construction of the SAR imaging interference model in step 1 is as follows:

[0059] The interference model of SAR imaging based on time-modulated metasurface is as follows: Figure 2 As shown in the figure, a two-dimensional rectangular coordinate system XOR is established on the SAR data acquisition plane. The SAR system moves from the origin O along the X-axis at a constant speed V, and the distance direction perpendicular to the flight trajectory to the center of the observation scene is recorded as the R axis. The time-modulated metasurface is placed on the surface p of the protected target in the observation scene. t (x0, R0), where (x0, R0) represents the target position; the instantaneous slant range between the SAR system and the protected target can be expressed as:

[0060]

[0061] Where: t m Indicates the azimuth slow time; R B =minR(t m ).

[0062] Assume that the LFM signal transmitted by the SAR system is expressed as:

[0063]

[0064] in: Indicates distance to fast time; T r represents the pulse width; rect(·) represents the rectangular function; f0 represents the center frequency of the transmitted signal; μ represents the modulation frequency of the transmitted LFM signal.

[0065] The time-modulated metasurface on the target surface intercepts the signal transmitted by the radar and performs interference modulation on it; since the metasurface itself does not actively radiate high-power signals to the outside world, it avoids the shortcomings of traditional active interference methods, which are high cost and easy to expose the target area; under the control of external bias voltage, the time metasurface can realize real-time modulation of the phase and amplitude information of the transmitted signal, and forward the modulated signal to the SAR imaging system. The SAR system performs detection and demodulation on the received interference echo signal, and its complex baseband interference signal can be expressed as:

[0066]

[0067] in: represents a modulation signal generated by a time-modulated metasurface; represents the unmodulated echo signal, and its expression is:

[0068]

[0069] Where: A represents the complex reflection coefficient of the target; T a represents the synthetic aperture time; λ and c represent the wavelength and the speed of light, respectively.

[0070] Since the phase or amplitude information in the SAR echo signal is destroyed by the modulation signal, false targets or defocused images appear in the SAR image after imaging processing, effectively realizing SAR imaging interference.

[0071] The design of the time-modulated metasurface in step 2 is as follows:

[0072] First, a reverse open metal structure is designed, and a lumped element, a varactor diode, is added between the two open metal structures. The equivalent capacitance is changed by adjusting the voltage on both sides of the varactor diode, so that the phase of the incident electromagnetic wave can be continuously changed. The designed electromagnetic metasurface unit structure and array structure are as follows: Figure 3 As shown, the array structure layout is achieved by performing a two-dimensional periodic translation of the unit structure, thereby realizing a complete two-dimensional electromagnetic metasurface array structure.

[0073] The establishment and generation of the two-dimensional multi-phase segmented modulation signal model in step three is specifically as follows:

[0074] The two-dimensional multi-phase segmented modulation signal based on the time-modulated metasurface can be expressed as:

[0075]

[0076] Where: Intra-pulse multi-phase segmented modulation signal and the pulse-to-pulse multi-phase segmented modulation signal p2(t m ) are respectively expressed as:

[0077]

[0078] Where: * represents convolution operation; τ1,T1,f1=1 / T1,φ p1 , P1, N1 represent the segment duration, modulation period, modulation frequency, modulation phase, number of intra-pulse phase segments, and number of repetitions of the intra-pulse modulation signal respectively; τ2, T2, f2 = 1 / T2, φ p2 , P2, N2 represent the segment duration, modulation period, modulation frequency, modulation phase, number of inter-pulse phase segments, and number of repetitions of the inter-pulse modulation signal respectively.

[0079] and p2(t m ) are expressed in the frequency domain as follows:

[0080]

[0081] Therefore, the interference signal can be expressed in the two-dimensional frequency domain as:

[0082]

[0083] in:

[0084] It can be seen from the above formula that after two-dimensional multi-phase segmented modulation processing, the spectrum of the interference signal is the periodic weighted expansion of the original echo spectrum along the range and azimuth directions. The periods in the range and azimuth directions are the modulation frequencies f1 and f2 respectively, and its amplitude is jointly modulated by multiple phases.

[0085] The SAR imaging processing and imaging interference effect analysis in step 4 are as follows:

[0086] The SAR interference signal is processed by range-Doppler SAR imaging. The interference signal after range matched filtering and range migration correction can be expressed as:

[0087]

[0088] Among them: B r Indicates the bandwidth of the transmitted signal; Indicates rounding up.

[0089] The above interference signal is processed by azimuth matched filtering to obtain the final interference SAR image, which is expressed as:

[0090]

[0091] Among them: B a represents the signal Doppler bandwidth; γ represents the Doppler modulation frequency;

[0092] It can be seen that (2N+1)×(2M+1) false targets are generated in the jamming SAR image, and the offset of the mnth false target in the range dimension and azimuth dimension can be expressed as:

[0093]

[0094] The specific tests are:

[0095] A reference target RT (0m, 0m) and three protected targets [PT1 (100m, -200m), PT2 (200m, 500m) and PT3 (-50m, 300m)] are set at the center of the imaging scene; the unmodulated radar echo is processed by range-Doppler SAR imaging to obtain the unmodulated original SAR imaging result, as shown in Figure 4 As shown, it can be observed that four targets with high focusing quality can be seen in the SAR image.

[0096] The echo signal of the protected target is modulated in two-dimensional multi-phase segments using the time-modulated metasurface. The intra-pulse and inter-pulse modulation frequencies are set to f1 = 504.95 kHz and f2 = 39.28 Hz, respectively. The intra-pulse and inter-pulse segment phases are set to φ p1 =0, 0.3π, 0.6π, π and φ q2 =0, 0.5π, 0.8π, π, the intra-pulse modulation phase and inter-pulse modulation phase are respectively as follows Figure 5 and Figure 6 As shown; after range-Doppler imaging processing, the interference imaging result is obtained, as shown Figure 7 As shown, it can be seen that after the two-dimensional multi-phase segmented modulation processing based on the time-modulated metasurface, the protected target PTi, (i=1, 2, 3) generates a two-dimensional false target array with a topological structure similar to that of the protected target, and the distance and azimuth offset of each false target are proportional to the modulation frequency; therefore, the method designed by the present invention has a high flexibility, high fidelity, and low-cost interference imaging effect.

[0097] The present invention utilizes a time-modulated metasurface to generate a two-dimensional multi-phase segmented modulation signal through an external control system, thereby realizing real-time phase modulation of a radar signal to generate a SAR interference signal. By processing the SAR interference signal, theoretical analysis and experimental results show that the present invention can generate a two-dimensional false target array with flexible and controllable distance and azimuth position and a topological structure similar to that of a protected target, and has a highly flexible, high-fidelity, low-cost interference imaging effect, and has strong practical application value.

[0098] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A SAR two-dimensional multi-phase segmented modulation jamming method based on time-modulated metasurface, characterized in that: The following steps are involved: Designing a time-modulated metasurface and installing it on the surface of a protected target; the time-modulated metasurface is composed of a plurality of periodically arranged metasurface units; The metasurface unit comprises a first substrate, the top surface of which is provided with two metal square rings with openings arranged in opposite directions and symmetrically, and a varactor diode is provided between the two metal square rings; the metal square rings are used to adjust the phase, amplitude and polarization state of the electromagnetic wave incident on the metasurface unit, and to reflect or transmit the electromagnetic wave; By changing the voltage applied to the two metal square rings, the voltage on both sides of the varactor diode is changed, and the equivalent capacitance of the varactor diode is adjusted in real time to adjust the phase of the electromagnetic wave incident on the metasurface unit to a continuous change; The time-modulated metasurface receives the transmission signal of the SAR radar, performs two-dimensional intra-pulse and inter-pulse multi-phase segmented modulation and reflection on the transmission signal, and deceives and interferes with the SAR radar through the reflected signal.

2. The SAR two-dimensional multi-phase segmented modulation jamming method based on time-modulated metasurface according to claim 1 is characterized in that: A metal grounding plate is disposed on the bottom surface of the first substrate, a second substrate is disposed on the bottom surface of the metal grounding plate, two bias lines are disposed on the bottom surface of the second substrate, and the two bias lines are respectively connected to corresponding metal square rings through two metal vias disposed on the first substrate; The metal grounding plate is located on the bottom surface of the first substrate and is used for electromagnetic shielding and grounding, while preventing electromagnetic waves from leaking and interfering inside the metasurface unit; The bias line is located on the bottom surface of the second substrate and is used to provide a DC voltage or current to the metal square ring to change the capacitance value of the variable capacitance diode to dynamically control the regulation of the metasurface electromagnetic wave.

3. The SAR two-dimensional multi-phase segmented modulation interference method based on time-modulated metasurface according to claim 2 is characterized in that: The method of performing two-dimensional intra-pulse and inter-pulse multi-phase segmented modulation on the transmission signal comprises: When the transmission signal of the SAR radar is incident on the time-modulated metasurface, the voltage on both sides of the varactor diode is changed by changing the voltage applied on the two bias lines, so as to adjust the equivalent capacitance of the varactor diode in real time, and the phase of the electromagnetic wave signal incident on the time-modulated metasurface is respectively subjected to two-dimensional intra-pulse multi-phase segmented modulation and slow-time two-dimensional inter-pulse multi-phase segmented modulation, and the intra-pulse multi-phase segmented modulation signal and the inter-pulse multi-phase segmented modulation signal are respectively obtained; The intra-pulse multi-phase segmented modulation signal and the inter-pulse multi-phase segmented modulation signal are respectively: in: represents the multi-phase segmented modulation signal within the pulse; p2(t m ) represents the pulse-to-pulse multi-phase segmented modulation signal; * represents the convolution operation; τ1,T1,f1=1 / T1,φ p1 , P1, N1 represent the segment duration, modulation period, modulation frequency, modulation phase, number of phase segments within the pulse, and number of repetitions of the intra-pulse multi-phase segment modulation signal respectively; τ2, T2, f2 = 1 / T2, φ p2 , P2, N2 represent the segment duration, modulation period, modulation frequency, modulation phase, number of segmentation between pulses, and number of repetitions of the inter-pulse multi-phase segmented modulation signal respectively; The two-dimensional multi-phase segmented modulation signal is: Where: t m Indicates slow time; Represents a two-dimensional multi-phase segmented modulation signal.

4. The SAR two-dimensional multi-phase segmented modulation jamming method based on time-modulated metasurface according to claim 1 is characterized in that: The formation of the reflection signal comprises: The time modulation metasurface on the stationary target receives the transmission signal of the SAR radar, and performs two-dimensional intra-pulse multi-phase segmented modulation and slow-time two-dimensional inter-pulse multi-phase segmented modulation on the transmission signal, obtains the intra-pulse multi-phase segmented modulation signal and the inter-pulse multi-phase segmented modulation signal, and forms a two-dimensional multi-phase segmented modulation signal; The spectrum of the two-dimensional multi-phase segmented modulation signal in the frequency domain is extracted, and the spectrum of the two-dimensional multi-phase segmented modulation signal is subjected to multiple periodic weighted expansions in the range and azimuth directions of the protected target, and the spectrum of the two-dimensional multi-phase segmented modulation signal is replaced with multiple different spectrums generated in the range and azimuth directions in sequence, respectively, to form multiple harmonic components of the two-dimensional multi-phase segmented modulation signal in the range and azimuth directions, and the multiple harmonic components in the range and azimuth directions are synthesized into a two-dimensional multi-phase segmented interference signal, and the two-dimensional multi-phase segmented interference signal is a reflected signal.

5. The SAR two-dimensional multi-phase segmented modulation interference method based on time-modulated metasurface according to claim 4 is characterized in that: The two-dimensional multi-phase segmented interference signal is: Wherein: f1 represents the modulation frequency of the intra-pulse multi-phase segmented modulation signal; f2 represents the modulation frequency of the inter-pulse multi-phase segmented modulation signal.

6. The SAR two-dimensional multi-phase segmented modulation jamming method based on time-modulated metasurface according to claim 5 is characterized in that: The deceptive interference to the SAR radar includes: The SAR radar receives the two-dimensional multi-phase segmented interference signal, and performs range matching filtering, range migration correction and clutter suppression on the interference signal, forming a false target array along the range and azimuth of the protected target in the interference image, thereby achieving interference to the SAR radar; The offsets of the mnth false target in the distance dimension and the azimuth dimension are: Wherein: f1 represents the modulation frequency of the multi-phase segmented modulation signal within a pulse; f2 represents the modulation frequency of the multi-phase segmented modulation signal between pulses; γ represents the Doppler modulation frequency in the distance direction; μ represents the Doppler modulation frequency in the azimuth direction; λ represents the wavelength; and c represents the speed of light.

7. A SAR two-dimensional multi-phase segmented modulation jammer based on a time-modulated metasurface, characterized in that: include: A design module, used to design a time-modulated metasurface and install it on the surface of the protection target; The time-modulated metasurface is composed of a plurality of periodically arranged metasurface units; The metasurface unit comprises a first substrate, the top surface of which is provided with two metal square rings with openings arranged in opposite directions and symmetrically, and a varactor diode is provided between the two metal square rings; the metal square rings are used to adjust the phase, amplitude and polarization state of the electromagnetic wave incident on the metasurface unit, and to reflect or transmit the electromagnetic wave; By changing the voltage applied to the two metal square rings, the voltage on both sides of the varactor diode is changed, and the equivalent capacitance of the varactor diode is adjusted in real time to adjust the phase of the electromagnetic wave incident on the metasurface unit to a continuous change; SAR radar jammer module, the time-modulated metasurface receives the transmission signal of the SAR radar, performs two-dimensional intra-pulse and inter-pulse multi-phase segmented modulation and reflection on the transmission signal, and deceives and jams the SAR radar through the reflected signal.

8. An electronic device, characterized in that: including memory and processor; The memory is used to store computer programs; The processor is used to implement the steps of the SAR two-dimensional multi-phase segmented modulation interference method based on time-modulated metasurface as described in any one of claims 1 to 6 when executing the computer program stored in the memory.

9. A computer-readable storage medium, characterized in that: Used to store a computer program, which, when executed by a processor, implements the steps of the SAR two-dimensional multi-phase segmented modulation interference method based on a time-modulated metasurface as described in any one of claims 1 to 6.

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