An RCS control circuit system and its design method

Abstract

The present invention discloses an RCS control circuit system and a design method thereof. The RCS control circuit system includes a microstrip Rotman lens and an RCS control circuit, so as to realize adjustable system RCS parameters. The RCS control circuit includes a switch, a circulator, and an amplifier. The output end of the amplifier is connected to the input end of the circulator. The output end of the circulator and the input end of the amplifier are simultaneously connected to the switch. The switch has an open state and a closed state. In the open state, the electromagnetic wave signal received by the Rotman lens returns along the original path and is attenuated at the beam port, thereby reducing the RCS of the system. In the closed state, the signal input at the beam port is power-amplified by the amplifier. The formed amplified signal, under the action of the circulator, passes through the switch again along the original circuit to return to the beam port, and re-stimulates the Rotman lens, thereby increasing the RCS of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of microstrip antennas, and in particular to an RCS control circuit system and a design method thereof. Background Art

[0002] The current antenna system has the following main problems:

[0003] (1) The rapid development of modern wireless communication systems and the rapid increase in the number of information users have led to an increasing shortage of spectrum resources. At the same time, the rapid development of military radar technology in detection and control has also put forward higher requirements for land vehicle, airborne and satellite communications. It is necessary to automatically create and maintain stable link communications during the receiving and transmitting antennas. Therefore, there is an urgent need for a new type of antenna system that is low-cost, high-gain, compact, and can achieve directional backtracking.

[0004] (2) Most traditional antennas require some complex beamforming algorithms and digital signal processing. Although this can improve the capacity and communication quality of the system, it is not suitable for communication systems that pursue large capacity and high speed due to its high price. Traditional phased array antennas usually use modules such as phase shifters and attenuators to control the excitation antenna unit. By adjusting the phase, retracement in a specific direction can be achieved. However, the complex and high-cost module components have also caused a bottleneck in research. In addition, commonly used directional retracement devices include corner reflectors and Van Atta antenna arrays. The former is based on a special physical structure and is impossible to modulate the backscattered signal to adjust the system RCS parameters. The latter has very low antenna efficiency due to the insertion loss of the long transmission line. Summary of the Invention

[0005] The object of the present invention is to provide an RCS control circuit system and a design method thereof, so as to realize the adjustable RCS control circuit.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] The present invention provides an RCS control circuit system, the RCS control circuit system comprising:

[0008] A microstrip Rotman lens and the RCS control circuit are combined to achieve adjustable system RCS parameters. The RCS control circuit includes a switch, a circulator, and an amplifier. The output of the amplifier is connected to the input of the circulator. The output of the circulator and the input of the amplifier are simultaneously connected to the switch. The switch has an open state and a closed state.

[0009] In the disconnected state, the electromagnetic wave signal received by the Rotman lens will return along the original path and attenuate at the beam port, thereby reducing the RCS of the system;

[0010] In the closed state, the signal input from the beam port is power amplified by the amplifier. The amplified signal, under the action of the circulator, passes through the switch again along the original circuit back to the beam port and re-stimulates the Rotman lens, thereby increasing the system RCS.

[0011] Optionally, the switch includes a switch chip U28; the circulator includes a circulator chip U23; and the amplifier includes an amplifier chip U18;

[0012] The GND pin of the switch chip U28 is grounded, its RF1 pin is connected to one end of the capacitor C63, its VDD pin is connected to the grounding capacitor C68 and one end of the resistor R83 at the same time, its LS pin is connected to one end of the resistor R88 and the grounding resistor R94 at the same time, its VCTRL pin is connected to the grounding resistor R98 and one end of the resistor R103 at the same time, its VSS pin is connected to the grounding capacitor C78 and one end of the resistor R108 at the same time, its RFC pin is connected to one end of the capacitor C73, the other end of the capacitor C63 is connected to the third port of the circulator chip U23, the other end of the resistor R83 and the other end of the resistor R88 are simultaneously connected to a 3.3V voltage, the other end of the resistor R103 is connected to a 3.3V voltage, the other end of the resistor R108 is connected to a 2.5V common ground voltage, and the other end of the capacitor C73 is connected to an input signal;

[0013] The VC pin of the amplifier chip U18 is connected to one end of the resistor R65, its RFIN / VG pin is simultaneously connected to one end of the capacitor C48 and one end of the resistor R66, its RFOUT / VD pin is simultaneously connected to one end of the capacitor C53 and one end of the resistor R73, the other end of the resistor R65 is connected to the 2V output voltage, the other end of the resistor R66 is simultaneously connected to the grounded capacitor C43 and one end of the resistor R58, the other end of the resistor R58 is connected to the 0.5V input voltage, the other end of the capacitor C48 is connected to the first port of the circulator chip U23, the other end of the capacitor C53 is connected to the second port of the circulator chip U23, the other end of the resistor R73 is simultaneously connected to the grounded capacitor C58 and one end of the resistor R78, and the other end of the resistor R78 is connected to the 5V voltage.

[0014] The present invention also provides a design method for an RCS control circuit system, the design method for the RCS control circuit system comprising:

[0015] S1: Generate the design equation of the Rotman lens based on the relevant characteristics of the Rotman lens;

[0016] S2: According to the design equation of the Rotman lens, a Rotman lens based on a microstrip form is obtained;

[0017] S3: According to the microstrip Rotman lens and the RCS control circuit, RCS parameters are adjustable.

[0018] Optionally, in step S1, the design equation for the Rotman lens is:

[0019]

[0020]

[0021] in, and are the horizontal and vertical coordinates of any point in the Rotman lens, is the focal length ratio of the Rotman lens, and are constants and , , is the defocus angle of the Rotman lens, and is a reference parameter and 、 , is the beam scanning angle of the Rotman lens, is the dielectric constant of the Rotman lens material, is a constant, is the off-axis focal length of the Rotman lens, is the length of the transmission line from any point inside the Rotman lens to the outer contour of the Rotman lens, is the transmission line length from the coordinate origin of the Rotman lens to the outer contour of the Rotman lens.

[0022] Optionally, step S2 includes:

[0023] S21: determining the position coordinates of any point in the Rotman lens according to the design equation of the Rotman lens;

[0024] S22: determining the structure of the inner contour of the Rotman lens according to the position coordinates of any point in the Rotman lens;

[0025] S23: determining a focal position and an off-axis focal position of the Rotman lens according to a structure of an inner contour of the Rotman lens;

[0026] S24: Obtaining a radius of a focusing arc of the Rotman lens according to the focal position and the off-axis focal position of the Rotman lens;

[0027] S25: Obtaining a profile of a beam port of the Rotman lens according to a radius of a focusing arc of the Rotman lens;

[0028] S26: determining the number of array ports in the inner contour of the Rotman lens according to the contour of the Rotman lens beam port;

[0029] S27: Obtaining the number of radiation elements of the array antenna according to the number of array ports in the inner contour of the Rotman lens;

[0030] S28: According to the number of array ports in the inner contour of the Rotman lens and the number of radiating elements of the array antenna, a phase-shifted transmission line connecting the array ports in the inner contour of the Rotman lens and the radiating elements of the array antenna is obtained, thereby obtaining the Rotman lens based on the microstrip form.

[0031] Optionally, step S3 includes:

[0032] Determining a switch, a circulator, and an amplifier of the RCS control circuit for the purpose of achieving adjustability of the RCS control circuit;

[0033] Controlling the switch to switch between an open state and a closed state;

[0034] According to the state change of the switch, the circulator, the amplifier and the Rotman lens based on the microstrip form, the RCS parameters are adjustable.

[0035] The present invention has the following beneficial effects:

[0036] This invention proposes a design that uses time reversal to achieve directional tracking and control the system's RCS parameters. This design offers advantages over traditional antennas, such as high gain, automatic rapid tracking, and multipath mitigation. Therefore, it has broad application prospects in the microwave and millimeter wave fields. It can be applied to radar, microwave power transmission, wireless communications, and satellite communications. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is the structural block diagram of the RCS control circuit;

[0038] Figure 2 This is the internal structure diagram of the HMC1118 switch;

[0039] Figure 3 This is the schematic diagram of the RCS control circuit;

[0040] Figure 4 Flowchart of the RCS control circuit design method provided by the present invention;

[0041] Figure 5 Schematic diagram of the working principle of the Rotman lens, (a) transmission mode; (b) receiving mode;

[0042] Figure 6 The geometric structure diagram of the Rotman lens;

[0043] Figure 7 is the normalized Rotman lens profile;

[0044] Figure 8 Schematic diagram of the Rotman lens phase-shift transmission line;

[0045] Figure 9 This is the complete structural diagram of the Rotman lens. DETAILED DESCRIPTION

[0046] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0047] Example

[0048] The technical solution of the present invention to solve the above technical problems is as follows:

[0049] The present invention provides an RCS control circuit system, the RCS control circuit system comprising:

[0050] A microstrip Rotman lens and the RCS control circuit are combined to achieve adjustable system RCS parameters. The RCS control circuit includes a switch, a circulator, and an amplifier. The output of the amplifier is connected to the input of the circulator. The output of the circulator and the input of the amplifier are simultaneously connected to the switch. The switch has an open state and a closed state.

[0051] In the disconnected state, the electromagnetic wave signal received by the Rotman lens will return along the original path and attenuate at the beam port, thereby reducing the RCS of the system;

[0052] In the closed state, the signal input from the beam port is power amplified by the amplifier. The amplified signal, under the action of the circulator, passes through the switch again along the original circuit back to the beam port and re-stimulates the Rotman lens, thereby increasing the system RCS.

[0053] like Figure 1 This is a block diagram of the system's RCS control circuit design. When the switch is off, the electromagnetic wave signal received by the Rotman lens will return along the original path and be attenuated at the beam port, thereby reducing the system's RCS. When the switch is closed, the signal input from the beam port will be amplified by the amplifier. Under the action of the circulator, the amplified signal will pass through the switch again along the original circuit back to the beam port and re-excite the lens, thereby increasing the system's RCS.

[0054] Optionally, the model of the switch is HMC1118; the model of the circulator is QMC-9500-10500-10; and the model of the amplifier is MAAM-011100.

[0055] according to Figure 1 In the structure, HMC1118 device is selected as the switch, which can operate in the frequency range of 9KHz to 13GHz, and has high isolation and low insertion loss. It only needs a positive 3.3V voltage and a negative ground voltage to cover a good operating frequency range, thus meeting the needs of the system circuit, such as Figure 2 This is the internal structure diagram of the HMC1118 switch. The MAAM-011100 device is selected as the amplifier. It is an easy-to-use, broadband, general-purpose variable-gain amplifier that operates between 400 MHz and 20 GHz. It has a flat gain control range of +10 dB to -20 dB and can provide up to +18 dBm of power and a 5 dB noise figure at the maximum gain setting. The QMC-9500-10500-10 device is selected as the circulator. It is a broadband, high-power, low-loss three-port device that can operate in the frequency range of 9.5 to 10.5 GHz.

[0056] According to the selected device, use Altium Designer software to draw its schematic diagram, such as Figure 3As shown, the GND pin of the switch HMC1118 is grounded, the RF1 pin is connected to one end of the capacitor C63, the VDD pin is connected to both the grounded capacitor C68 and one end of the resistor R83, the LS pin is connected to both one end of the resistor R88 and the grounded resistor R94, the VCTRL pin is connected to both the grounded resistor R98 and one end of the resistor R103, the VSS pin is connected to both the grounded capacitor C78 and one end of the resistor R108, the RFC pin is connected to one end of the capacitor C73, the other end of the capacitor C63 is connected to port 3 of the circulator QMC-9500-10500-10, the other end of the resistor R83 and the other end of the resistor R88 are both connected to a 3.3V voltage, the other end of the resistor R103 is connected to a 3.3V voltage, the other end of the resistor R108 is connected to a 2.5V common ground voltage, and the other end of the capacitor C73 is connected to the input signal;

[0057] The VC pin of the amplifier MAAM-011100 is connected to one end of the resistor R65, the RFIN / VG pin is simultaneously connected to one end of the capacitor C48 and one end of the resistor R66, the RFOUT / VD pin is simultaneously connected to one end of the capacitor C53 and one end of the resistor R73, the other end of the resistor R65 is connected to the 2V output voltage, the other end of the resistor R66 is simultaneously connected to the grounded capacitor C43 and one end of the resistor R58, the other end of the resistor R58 is connected to the 0.5V input voltage, the other end of the capacitor C48 is connected to port 1 of the circulator QMC-9500-10500-10, the other end of the capacitor C53 is connected to port 2 of the circulator QMC-9500-10500-10, the other end of the resistor R73 is simultaneously connected to the grounded capacitor C58 and one end of the resistor R78, and the other end of the resistor R78 is connected to a 5V voltage.

[0058] The electromagnetic wave signal passes through the HMC1118 switch path, inputs from port 3 of the QMC-9500-10500-10 circulator, and outputs from port 1. It is then amplified by the MAAM-011100 amplifier, inputs from port 2 of the circulator, and outputs from port 1. This structural design allows for controlled signal power, thereby re-exciting the beam port.

[0059] The present invention provides a RCS control circuit design method, referring to Figure 4 As shown, the RCS control circuit design method includes:

[0060] S1: Generate the design equation of the Rotman lens based on the relevant characteristics of the Rotman lens;

[0061] The Rotman lens is a broadband microwave beamforming network (BFN) that is commonly used to feed a linear array of antennas. The structure consists of an input beam port, an output array port, a parallel plate waveguide, and a properly selected transmission line length connected to the array port. The beam port profile and the array port profile together determine the shape of the lens, such as Figure 5 When the input beam port is excited, the optical path length provided by the parallel plate and the array feed line produces a linear delay between the array ports, thereby generating a wavefront that is tilted at a certain angle to the array. The cross section of the trifocal Rotman lens is shown in Figure 5 As shown, we can see the on-axis focus G and two symmetrical off-axis focuses F1 and F2. The input beam port at the on-axis focus G corresponds to the aimed directional vertical beam, and the beam ports at the off-axis focuses F1 and F2 correspond to the tilted beams, which determine the scanning range of the plane beam of the entire system. Similarly, the non-ideal off-axis focuses can be symmetrically expanded in pairs on the beam port profile to improve the phase resolution of the generated plane beam. The array port of the Rotman lens is also called the inner profile. It has the same number of connection ports as the array antenna and is connected to the phase-shifted transmission lines. These transmission lines are connected to the corresponding array antennas. The plane where these array antennas are located is called the outer profile of the Rotman lens. The microstrip transmission lines therein have different lengths. The purpose is to correct the phase error and thus generate a plane wavefront on the radiating element.

[0062] like Figure 5 As shown, the lossless Rotman lens can be divided into receiving mode and transmitting mode, whose operations are almost completely opposite. In the transmitting mode, excitation is applied at each beam port to form plane beams in different directions. In the receiving mode, the signal phase sampled at each antenna array element is a function of the plane wave's arrival angle. The energy propagated through the BFN is summed in phase at the beam port profile. Geometric optics shows that when the signal source is located in one of the array's main beams, the energy can be focused on the corresponding beam port; when the signal source is located between two main beams, the energy is focused on both beam ports. Therefore, the beam port where the signal is focused depends on the arrival angle of the incident wavefront. When the port is terminated with an open circuit or a short circuit, the signal is reflected again, entering the transmitting mode. Due to the principle of reciprocity, the plane wave phase is conjugated, and the reradiated wavefront points toward the source, resulting in a directional backtracking phenomenon observed throughout the entire scanning range.

[0063] like Figure 6 The figure shows a Rotman lens, including relevant parameters of the lens profile. The present invention analyzes the Rotman lens based on the equal optical path principle in optics and derives its design equation to determine the basic profile of the lens.

[0064] In the present invention, the design equation for the Rotman lens is:

[0065]

[0066]

[0067] in, and are the horizontal and vertical coordinates of any point in the Rotman lens, is the focal length ratio of the Rotman lens, and are constants and , , is the defocus angle of the Rotman lens, and is a reference parameter and 、 , is the beam scanning angle of the Rotman lens, is the dielectric constant of the Rotman lens material, is a constant, is the off-axis focal length of the Rotman lens, is the length of the transmission line from any point inside the Rotman lens to the outer contour of the Rotman lens, is the transmission line length from the coordinate origin of the Rotman lens to the outer contour of the Rotman lens.

[0068] like Figure 6 As shown, set the symmetry center of the lens inner contour As the coordinate origin, the midpoint is any point on the inner contour of the lens, then the shape of the inner contour will be determined by the point The arc where it is located is determined by the point on the inner contour. and the coordinate origin The transmission line lengths to the outer contour of the lens are expressed as and Two off-axis foci and To the coordinate origin distance and is called the off-axis focal length, while the central focal length Distance to the origin It is called the positive focal length. and The angle between The maximum angle of the plane beam scanning range is called the defocus angle. The working process of the Rotman lens is based on the principle of equal optical path in optics. Specifically, it can be described as follows: the optical path that a ray emitted from any beam port travels through the lens cavity to any point on the inner contour and then through the transmission line to reach the wavefront is equal to the optical path that the ray emitted through the port travels through the coordinate origin and then reaches the wavefront. Figure 3 As shown, according to the principle of equal optical path, the focus is , and focus The electromagnetic waves emitted pass through the points and transmission lines The phase shift produced is related to the phase shift through the origin. and transmission lines The phase shifts produced by the arriving wavefronts are equal, based on which the following three first mathematical equations can be derived:

[0069]

[0070]

[0071]

[0072] Transform the above three mathematical equations according to the trigonometric function transformation formula to obtain three second mathematical equations:

[0073]

[0074]

[0075]

[0076] In the formula and Any point in the Rotman lens In addition, the first three mathematical equations do not consider the dielectric filling problem of the lens cavity. Therefore, it is assumed that the dielectric constant of the material is Indicates that the three first mathematical equations can be rewritten into three third mathematical equations, namely:

[0077]

[0078]

[0079]

[0080] The parameters in the three second mathematical equations and the three third mathematical equations are processed using represents the off-axis focal length of the Rotman lens. The first normalization result is:

[0081]

[0082] Substituting the normalized results into the three second mathematical equations and the three third mathematical equations, they can be expressed as three fourth mathematical equations, namely:

[0083]

[0084]

[0085]

[0086] Then, the three fourth mathematical equations are normalized to obtain the second normalized result:

[0087]

[0088]

[0089]

[0090] By combining all the equations of the second normalization results above, we can get the first simultaneous result:

[0091]

[0092] Since the structure of the Rotman lens is symmetrical, no matter the point lie in The upper and lower half axes will not affect the correctness of the joint results. Splitting the above joint results, we can get the split results as follows:

[0093]

[0094]

[0095] Then combine them and get the second joint result:

[0096]

[0097] According to the split results And the second joint result, we can get Solution:

[0098]

[0099] From the split result , the second joint result and The solution to The relevant mathematical equations are:

[0100]

[0101] in:

[0102]

[0103] Based on the above, appropriate parameters are selected in advance according to the desired Rotman lens structure to calculate The value of Can get The value of , so using the formula and Able to calculate points The position coordinates of the lens are used to determine the structure of the inner contour of the lens. At the same time, the beam port contour of the lens is determined by the focal point and the off-axis focus. Therefore, after determining the focal position, the radius of the focusing arc can be calculated to determine the contour of the beam port.

[0104] S2: According to the design equation of the Rotman lens, a Rotman lens based on a microstrip form is obtained;

[0105] Optionally, step S2 includes:

[0106] S21: determining the position coordinates of any point in the Rotman lens according to the design equation of the Rotman lens;

[0107] Based on the above, when generating the design equation for the Rotman lens, the position coordinates of any point in the Rotman lens can be determined, that is, .

[0108] S22: determining the structure of the inner contour of the Rotman lens according to the position coordinates of any point in the Rotman lens;

[0109] Since any point in the Rotman lens has been determined Therefore, using the position coordinates of The structure of the inner contour of the Rotman lens can be obtained by modeling the equation.

[0110] S23: determining a focal position and an off-axis focal position of the Rotman lens according to a structure of an inner contour of the Rotman lens;

[0111] refer to Figure 6 As shown, the structure of the inner contour of the Rotman lens is determined, that is, the focal position and off-axis focal position of the Rotman lens can be determined according to the structure.

[0112] S24: Obtaining a radius of a focusing arc of the Rotman lens according to the focal position and the off-axis focal position of the Rotman lens;

[0113] Since the beam port profile of the lens is determined by the focal point and the off-axis focus, the radius of the focusing arc can be calculated after the focal position is determined.

[0114] S25: Obtaining a profile of a beam port of the Rotman lens according to a radius of a focusing arc of the Rotman lens;

[0115] S26: determining the number of array ports in the inner contour of the Rotman lens according to the contour of the Rotman lens beam port;

[0116] Table 1 summarizes the basic parameters of the Rotman lens of the present invention:

[0117] Table 1 Basic parameters of Rotman lens

[0118]

[0119] Based on the parameters in Table 1, the design equation of the Rotman lens is used to draw the outline of the Rotman lens using Matlab. Figure 7 As shown, the coordinate dimensions are normalized using the positive axis focal length. The circles on the left and right represent the phase centers of the beam port and array port, respectively. Based on the phase centers, the microstrip transmission line can be drawn. The microstrip transmission line has a gradually narrowing conical structure. The purpose is to achieve impedance matching from the lens cavity to the microstrip transmission line, thereby reducing electromagnetic wave loss.

[0120] S27: Obtaining the number of radiation elements of the array antenna according to the number of array ports in the inner contour of the Rotman lens;

[0121] Since the number of array ports in the inner contour of the Rotman lens corresponds one-to-one to the number of radiating elements of the array antenna, when the number of array ports in the inner contour of the Rotman lens is determined, the number of radiating elements of the array antenna can also be determined accordingly.

[0122] Since the number of radiating elements of the array antenna determines the size of the subsequent antenna design, and the more radiating elements there are, the greater the gain of the array antenna will be, after comprehensive consideration, the number of lens array ports designed in the present invention is set to 10, and the spacing between the radiating elements is usually set to 0.5 times the free space wavelength, which can meet the grating lobe suppression conditions. Secondly, the beam scanning angle is set to 45° according to actual needs, and the lens defocus angle is determined to be 75°. These parameters will affect the profile of the lens beam port. At the same time, under the premise of determining the maximum range of the beam scanning angle, the number of lens beam ports can affect the resolution of the beam direction. Therefore, setting the number of beam ports to 13 can also reduce beam pointing errors and backward lens losses. In addition, the virtual absorption port of the lens is intended to reduce the scattering loss of the signal. Theoretically, its number is not clearly defined, but based on actual modeling and processing conditions, it is usually determined based on the size of the lens and the spacing between the beam port and the array port. The present invention determines it to be 4 above and 4 below.

[0123] S28: According to the number of array ports in the inner contour of the Rotman lens and the number of radiating elements of the array antenna, a phase-shifted transmission line connecting the array ports in the inner contour of the Rotman lens and the radiating elements of the array antenna is obtained, thereby obtaining the Rotman lens based on the microstrip form.

[0124] Phase-shifting transmission lines play a crucial role in microstrip Rotman lens designs. Besides meeting the requirements for high-frequency electromagnetic wave transmission, they also provide phase correction. Variations in microstrip line lengths throughout the lens' input and output sections can affect the input and output phases, necessitating the addition of phase-shifting transmission lines of varying lengths between the lens' inner contour and the array port.

[0125] Phase-shift transmission lines usually need to ensure a relatively flat phase change characteristic within the operating frequency band. At the same time, they should ensure minimal electromagnetic wave loss when operating based on high-frequency signals. Therefore, arc-shaped microstrip lines are used. Compared with angled microstrip lines, they have less reflection of high-frequency energy and better standing waves. Figure 8 The figure shows a schematic diagram of the microstrip transmission line of the Rotman lens. Its length only needs to ensure that the output phases of each array port are consistent when the input is at the center of the beam port.

[0126] Figure 9 This is the complete structural diagram of the Rotman lens.

[0127] S3: According to the microstrip Rotman lens and the RCS control circuit, RCS parameters are adjustable.

[0128] Optionally, step S3 includes:

[0129] Determining a switch, a circulator, and an amplifier of the RCS control circuit for the purpose of achieving adjustability of the RCS control circuit;

[0130] Controlling the switch to switch between an open state and a closed state;

[0131] According to the state change of the switch, the circulator, the amplifier and the Rotman lens based on the microstrip form, the RCS parameters are adjustable.

[0132] This invention proposes a design scheme based on time reversal to achieve directional tracking and control the system's RCS parameters. This design offers advantages not found in traditional antennas, such as high gain, automatic rapid tracking, and multipath mitigation. Therefore, it has broad application prospects in the microwave and millimeter wave fields. It has potential applications in radar, microwave power transmission, wireless communications, and satellite communications. The development and application of this technology is expected to become a new research hotspot, potentially bringing significant commercial and social benefits.

[0133] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An RCS control circuit system, characterized in that: The RCS control circuit system includes: A microstrip Rotman lens and the RCS control circuit are combined to achieve adjustable system RCS parameters. The RCS control circuit includes a switch, a circulator, and an amplifier. The output of the amplifier is connected to the input of the circulator. The output of the circulator and the input of the amplifier are simultaneously connected to the switch. The switch has an open state and a closed state. In the disconnected state, the electromagnetic wave signal received by the Rotman lens will return along the original path and attenuate at the beam port, thereby reducing the RCS of the system; In the closed state, the signal input from the beam port is power amplified by the amplifier. The amplified signal, under the action of the circulator, passes through the switch again along the original circuit back to the beam port and re-stimulates the Rotman lens, thereby increasing the system RCS. The design method of the RCS control circuit system includes: S1: Generate the design equation of the Rotman lens based on the relevant characteristics of the Rotman lens; The design equation for the Rotman lens is: in, and are the horizontal and vertical coordinates of any point in the Rotman lens, is the focal length ratio of the Rotman lens, and are constants and , , is the defocus angle of the Rotman lens, and is a reference parameter and 、 , is the beam scanning angle of the Rotman lens, is the dielectric constant of the Rotman lens material, is a constant, is the off-axis focal length of the Rotman lens, is the length of the transmission line from any point inside the Rotman lens to the outer contour of the Rotman lens, is the transmission line length from the coordinate origin of the Rotman lens to the outer contour of the Rotman lens; S2: According to the design equation of the Rotman lens, a Rotman lens based on a microstrip form is obtained; The step S2 comprises: S21: determining the position coordinates of any point in the Rotman lens according to the design equation of the Rotman lens; S22: determining the structure of the inner contour of the Rotman lens according to the position coordinates of any point in the Rotman lens; S23: determining a focal position and an off-axis focal position of the Rotman lens according to a structure of an inner contour of the Rotman lens; S24: Obtaining a radius of a focusing arc of the Rotman lens according to the focal position and the off-axis focal position of the Rotman lens; S25: Obtaining a profile of a beam port of the Rotman lens according to a radius of a focusing arc of the Rotman lens; S26: determining the number of array ports in the inner contour of the Rotman lens according to the contour of the Rotman lens beam port; S27: Obtaining the number of radiation elements of the array antenna according to the number of array ports in the inner contour of the Rotman lens; S28: obtaining, according to the number of array ports in the inner contour of the Rotman lens and the number of radiating elements of the array antenna, phase-shifted transmission lines connecting the array ports in the inner contour of the Rotman lens and the radiating elements of the array antenna, thereby obtaining the microstrip-based Rotman lens; S3: According to the microstrip Rotman lens and the RCS control circuit, the RCS parameters are adjustable; The step S3 comprises: Determining a switch, a circulator, and an amplifier of the RCS control circuit for the purpose of achieving adjustability of the RCS control circuit; Controlling the switch to switch between an open state and a closed state; According to the state change of the switch, the circulator, the amplifier and the Rotman lens based on the microstrip form, the RCS parameters are adjustable.

2. The RCS control circuit system according to claim 1, characterized in that: The switch includes a switch chip U28; the circulator includes a circulator chip U23; the amplifier includes an amplifier chip U18; The GND pin of the switch chip U28 is grounded, its RF1 pin is connected to one end of the capacitor C63, its VDD pin is connected to the grounding capacitor C68 and one end of the resistor R83 at the same time, its LS pin is connected to one end of the resistor R88 and the grounding resistor R94 at the same time, its VCTRL pin is connected to the grounding resistor R98 and one end of the resistor R103 at the same time, its VSS pin is connected to the grounding capacitor C78 and one end of the resistor R108 at the same time, its RFC pin is connected to one end of the capacitor C73, the other end of the capacitor C63 is connected to the third port of the circulator chip U23, the other end of the resistor R83 and the other end of the resistor R88 are simultaneously connected to a 3.3V voltage, the other end of the resistor R103 is connected to a 3.3V voltage, the other end of the resistor R108 is connected to a 2.5V common ground voltage, and the other end of the capacitor C73 is connected to an input signal; The VC pin of the amplifier chip U18 is connected to one end of the resistor R65, its RFIN / VG pin is simultaneously connected to one end of the capacitor C48 and one end of the resistor R66, its RFOUT / VD pin is simultaneously connected to one end of the capacitor C53 and one end of the resistor R73, the other end of the resistor R65 is connected to the 2V output voltage, the other end of the resistor R66 is simultaneously connected to the grounded capacitor C43 and one end of the resistor R58, the other end of the resistor R58 is connected to the 0.5V input voltage, the other end of the capacitor C48 is connected to the first port of the circulator chip U23, the other end of the capacitor C53 is connected to the second port of the circulator chip U23, the other end of the resistor R73 is simultaneously connected to the grounded capacitor C58 and one end of the resistor R78, and the other end of the resistor R78 is connected to the 5V voltage.

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