Jamming method for producing radar false targets

Abstract

The present application relates to the interference method for generating radar false target, belongs to the technical field of antenna radar scattering. The method is: radar transmits electromagnetic wave to detect target; electromagnetic wave reaches echo control structure; modulation signal generator generates specific modulation signal and sends to the control structure; modulation signal on the control structure and electromagnetic wave signal are convolved in frequency domain to realize frequency spectrum shift; radar receives and processes electromagnetic echo signal, and multiple harmonic false targets appear in one-dimensional distance direction; the present application proposes to adjust the radar false target interference by controlling the frequency of modulation signal generator according to the needs, can realize the energy attenuation in one-dimensional distance direction, and a single radar target becomes many false targets, and the imaging radar can be effectively passively interfered by making the radar target fuzzy and generating many false targets.

Description

Technical Field

[0001] This invention belongs to the field of antenna radar scattering technology and relates to an interference method for generating radar false targets. Background Technology

[0002] In modern warfare, the battlefield environment is becoming increasingly transparent. When one side gains the upper hand in electronic warfare, it gains the initiative. Therefore, major military powers worldwide are actively developing high-performance electronic countermeasures technologies. Thanks to the rapid development of modern technology, electronic information technology plays an increasingly important role on the battlefield. It is widely used in battlefield command, communication, control, and radar detection, leading to revolutionary advancements in weaponry. It can be said that electronic information technology plays a decisive role in the development and modernization of modern high-tech weaponry. Electronic protection technology, as a crucial component of electronic information warfare, is applied to all aspects of warfare, and in certain specific battlefields, it has even played a decisive role in influencing the outcome of a war.

[0003] With the development of modern radar detection technology, modern military radar detection systems have become increasingly integrated and intelligent, making it easier for air combat units to be detected and intercepted. At the same time, with the development of electronic countermeasures technology, modern air combat units possess numerous means to avoid radar detection and achieve radar stealth. These include using radar-absorbing materials and specially designed shapes to reduce radar wave reflection, making them difficult to detect in radar imaging, and using radar decoy technology to generate multiple false targets to confuse enemy radar detection and achieve strategic objectives.

[0004] Most existing radar decoy technologies, including corner reflectors and Luneburg lenses, have fixed characteristics after processing, making it difficult to dynamically change the azimuth coordinates of radar decoys. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide an interference method for generating radar false targets, thereby achieving interference with radar echo detection by generating multiple false targets and achieving radar stealth. This invention proposes a radar echo modulation structure for generating radar false target interference, which can adjust the radar false target interference as needed by controlling the frequency of the modulation signal generator, etc. It can realize that while the energy in the one-dimensional range direction is attenuated, a single radar target is transformed into many false targets. By blurring the radar target and generating many false targets, effective passive interference against imaging radar can be achieved.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The method for generating radar false targets is as follows:

[0008] Radar emits electromagnetic waves to detect targets;

[0009] Electromagnetic waves arrive at the echo control structure, namely the VanAtta antenna pair structure;

[0010] The modulation signal generator produces sine waves, square waves, or triangular waves of 0–50 MHz and sends them to the VanAtta antenna pair structure.

[0011] The frequency domain convolution between the modulation signal and the electromagnetic wave signal on the echo modulation structure achieves spectrum shifting.

[0012] The radar receives and processes electromagnetic echo signals, resulting in multi-level harmonic false targets in the one-dimensional range direction;

[0013] When electromagnetic waves irradiate the surface of the VanAtta antenna pair, a control voltage is applied to both sides of the PIN diode to control the PIN diode to present two states of low impedance and high impedance to the radio frequency signal, thereby controlling the on and off of the transmission line and making the VanAtta antenna pair in two different phase states. This enables the modulation signal generator to control the on and off of the PIN diode.

[0014] The VanAtta antenna pair consists of three layers. The first layer is a microstrip patch antenna element, which is composed of two microstrip patch antenna elements, a PIN diode, and a microstrip connection line, wherein the PIN diode is placed in the middle of the microstrip transmission line; the second layer is a dielectric layer of a certain thickness with a dielectric constant of 1; and the third layer is a ground plane made of copper.

[0015] The two elements of the Van Atta antenna pair are symmetrically distributed and connected by a microstrip transmission line and a PIN diode. The two ends of the PIN diode are respectively connected to the signal output port of the modulation signal generator, and the lengths of the microstrip transmission lines on both sides of the PIN diode are the same. When the PIN diode is in the off state, the Van Atta antenna pair is destroyed, and the induced current on the Van Atta antenna pair reaches the two ends of the PIN diode and returns, with the current traveling the same distance. When the PIN diode is in the on state, the two microstrip patch antenna elements are connected to form the Van Atta antenna pair, realizing electromagnetic echo modulation.

[0016] Optionally, the VanAtta antenna pair is composed of pairs of patch elements, fabricated using planar printed patch antennas, and can conformally fit onto the surface of an object.

[0017] Optionally, the VanAtta antenna pair is connected to another VanAtta antenna pair by a microstrip transmission line, with a PIN diode in the middle of the microstrip transmission line. A bias voltage can be applied to both ends of the PIN diode to control its switching on and off.

[0018] Optionally, the operating frequency of the VanAtta antenna pair is controlled by the corresponding antenna element size, and changing the corresponding antenna element size allows the VanAtta antenna pair to operate at different frequencies.

[0019] Optionally, the antenna element spacing in the VanAtta antenna pair satisfies the different echo phases of different PIN diode impedances, and changing the PIN diode impedance achieves a radar echo phase difference of 180°.

[0020] The beneficial effects of this invention are as follows: by using a modulation signal generator to generate a control signal, the switching of the PIN diode is achieved, thereby making the radar echo present a phase difference of 180°; by controlling the frequency of the bias voltage across the PIN diode, the radar echo is regulated, thereby reducing the power of the echo at the intermediate frequency and generating multiple harmonics, thus forming multiple radar false targets to interfere with enemy radar detection. It can be applied to the surface of aircraft without changing the shape and size of the reflective structure, and has the advantages of being lightweight, small in size, and easy to conformally integrate with aircraft.

[0021] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0022] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0023] Figure 1 The flowchart of the radar false target generation method provided by the present invention.

[0024] Figure 2 This is a schematic diagram of an embodiment of the radar false target generation method provided by the present invention.

[0025] Figure 3 This is a schematic diagram of an antenna unit provided in an embodiment of the present invention.

[0026] Figure 4 This is a schematic diagram of antenna unit S11 provided in an embodiment of the present invention.

[0027] Figure 5 This is a schematic diagram of the on / off phase of a binary array PIN diode provided in an embodiment of the present invention.

[0028] Figure 6 This is a schematic diagram of a radar decoy provided in an embodiment of the present invention.

[0029] Reference numerals: Microstrip patch antenna element 1, dielectric layer 2, copper ground plane 3, Van Atta antenna pair first element 11, Van Atta antenna pair second element 12, first microstrip transmission line 21, second microstrip transmission line 22, PIN diode 3, first modulation signal line 41, second modulation signal line 42, modulation signal generator 5. Detailed Implementation

[0030] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0031] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0032] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0033] like Figure 1The diagram shows the specific workflow of this embodiment. First, the radar emits electromagnetic wave signals to detect airborne targets. The electromagnetic wave signals propagate in free space and then illuminate the surface of the embodiment's structure. Simultaneously, a modulation signal generator produces a specific modulation signal that reaches both ends of the PIN diode in the embodiment's structure, thereby controlling the diode's on / off state to achieve a phase change on / off state at the embodiment's surface. Subsequently, the signal on the embodiment's structure surface is multiplied with the arriving electromagnetic wave signal in the time domain, and convolution occurs in the frequency domain, thereby achieving a spectrum shifting effect. When the radar receives and processes the electromagnetic echo signal, multi-level harmonic false targets appear during one-dimensional range-direction energy analysis, ultimately achieving the purpose of interfering with the radar's target detection.

[0034] like Figure 2 As shown, the structure of this specific embodiment includes a Van Atta antenna pair first element 11, a Van Atta antenna pair second element 12, a first microstrip transmission line 21, a second microstrip transmission line 22, a PIN diode 3, a first modulation signal line 41, a second modulation signal line 42, and a modulation signal generator 5. In this embodiment, the operating frequency band of the Van Atta antenna pair element is in the range of 400MHz to 450MHz. In other embodiments, the array element structure, the number of array elements, and the array element spacing are determined according to actual requirements.

[0035] In this embodiment, the two elements of the Van Atta antenna pair are symmetrically distributed and connected via microstrip transmission lines and PIN diodes. The two ends of the PIN diodes are respectively connected to the signal output ports of the modulation signal generator, and the lengths of the microstrip transmission lines on both sides of the PIN diodes should be equal. When the diodes are in the off state, the Van Atta antenna pair is disrupted; the induced current on the structural unit reaches the two ends of the diodes and returns, with the current traveling the same distance. When the diodes are in the on state, the two microstrip patch antenna elements are connected to form the Van Atta antenna pair, achieving electromagnetic echo modulation.

[0036] To verify the effect of controlling the voltage across the PIN diode to achieve the surface phase change of the Van Atta antenna, this embodiment uses CST simulation software for simulation verification. Figure 3 The image shows the Van Atta antenna pair unit of this embodiment. The left image shows the front of the unit, and the right image shows the side of the unit. It includes a microstrip patch antenna unit 1, a dielectric layer 2, and a copper ground plane 3. Its center frequency is 420MHz.

[0037] The S11 parameters of the microstrip patch antenna element are as follows: Figure 5 As shown, it can be seen that its S11 parameter is less than -16dB at a frequency of 420MHz, and it can work in a specific frequency band.

[0038] The electromagnetic echo power obtained from the simulation is as follows: Figure 6As shown in the diagram, the dashed line represents the original monophonic radar detection signal with a frequency of 425MHz. After being modulated by a modulation signal with a frequency of 20MHz, it becomes... Figure 6 The solid line signal in the signal transforms the electromagnetic echo signal from a single-tone signal to a multi-level harmonic signal, achieving the effect of creating multi-level false targets in the one-dimensional distance direction and blurring the distance and position of the real target.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for generating radar false targets, characterized in that: The method is as follows: Radar emits electromagnetic waves to detect targets; Electromagnetic waves arrive at the echo control structure, namely the Van Atta antenna pair structure; The modulation signal generator produces sine waves, square waves, or triangular waves from 0 to 50 MHz and sends them to the Van Atta antenna pair structure. The frequency domain convolution between the modulation signal and the electromagnetic wave signal on the echo modulation structure achieves spectrum shifting. The radar receives and processes electromagnetic echo signals, resulting in multi-level harmonic false targets in the one-dimensional range direction; When electromagnetic waves irradiate the surface of the Van Atta antenna pair, a control voltage is applied to both sides of the PIN diode to control the PIN diode to present two states of low impedance and high impedance to the radio frequency signal, thereby controlling the on and off of the transmission line and making the Van Atta antenna pair in two different phase states. This enables the modulation signal generator to control the on and off of the PIN diode. The Van Atta antenna pair consists of three layers. The first layer is a microstrip patch antenna element, which is composed of two microstrip patch antenna elements, a PIN diode, and a microstrip connection line, wherein the PIN diode is placed in the middle of the microstrip transmission line; the second layer is a dielectric layer of a specific thickness with a dielectric constant of 1; and the third layer is a ground plane made of copper. The two elements of the Van Atta antenna pair are symmetrically distributed and connected by a microstrip transmission line and a PIN diode. The two ends of the PIN diode are respectively connected to the signal output port of the modulation signal generator, and the lengths of the microstrip transmission lines on both sides of the PIN diode are the same. When the PIN diode is in the off state, the Van Atta antenna pair is destroyed, and the induced current on the Van Atta antenna pair reaches the two ends of the PIN diode and returns, with the current traveling the same distance. When the PIN diode is in the on state, the two microstrip patch antenna elements are connected to form the Van Atta antenna pair, realizing electromagnetic echo modulation. The radar echo is modulated by controlling the frequency of the bias voltage across the PIN diode, thereby reducing the power of the echo at the intermediate frequency and generating multiple harmonics to form multiple radar false targets to interfere with the enemy's radar detection. The Van Atta antenna pair is connected to another Van Atta antenna pair by a microstrip transmission line. The middle of the microstrip transmission line is a PIN diode, and a bias voltage can be applied to both ends of the PIN diode to control the switching of the diode. The operating frequency of the Van Atta antenna pair is controlled by the size of the corresponding antenna element. Changing the size of the corresponding antenna element allows the Van Atta antenna pair to operate at different frequencies. The spacing between antenna elements in the Van Atta antenna pair satisfies the requirement that different PIN diode impedances result in different echo phases, and changing the PIN diode impedance achieves a radar echo phase difference of 180°.

2. The interference method for generating radar false targets according to claim 1, characterized in that: The Van Atta antenna pair consists of pairs of patch elements, which are fabricated using planar printed patch antennas and can conform to the surface of an object.

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