Signal Multipath Effect Simulation System

Abstract

The present invention provides a signal multipath effect simulation system, which includes a radio frequency signal generator, a power splitter, a plurality of signal simulation devices, a power combiner, and a signal receiver. Each signal simulation device is used to simulate signals with different time delays. The signal simulation device includes an amplitude controller and a single-signal simulator connected in transmission. The amplitude controller is used to control the amplitude of the signal. The single-signal simulator includes a time delay control board, a waveguide transmission structure, and a radio frequency switch. The waveguide transmission structure includes a plurality of transmission paths with different lengths. The radio frequency switch is used to selectively conduct each transmission path. The radio frequency switch and at least some of the transmission paths are both arranged on the time delay control board. The signal multipath effect simulation system provided by the present invention can, through the coordinated operation of a plurality of single-channel simulators, simulate the multipath effect in a complex channel environment in real time and accurately, and provide high-precision channel characteristic simulation.

Description

Technical Field

[0001] The invention belongs to the technical field of signal transmission, and more specifically, relates to a signal multipath effect simulation system. Background Art

[0002] In mobile communication systems, the multipath propagation effect caused by complex electromagnetic environments will significantly affect the communication quality, especially in high frequency bands (such as millimeter wave bands) and strong reflection environments (such as cabins and spacecraft metal cavities). In scenarios where metal is the main reflection surface, non-line-of-sight propagation (NLOS) accounts for almost more than 90%, and the delay-power distribution of multipath signals presents a dense superposition characteristic, which puts higher requirements on the establishment and verification of channel models. Traditional channel modeling methods rely on a large amount of measurement data from actual scenarios to generate statistical models, and then design communication system solutions based on model parameters. However, physical channel measurement consumes a lot of resources and is difficult to verify repeatedly in dynamic scenarios. It has the problems of high cost, lengthy cycle and difficulty in dynamically reconstructing scenarios. Channel simulators have become a key tool to replace actual measurements, but existing solutions have significant limitations in delay control accuracy, scalability and hardware cost control in millimeter wave bands, especially in meeting key requirements such as adjustable delay of multipath signal distribution and multipath superposition.

[0003] The core challenge of channel multipath effect simulation is to reproduce the delay spread characteristics with high precision, that is, the time, amplitude and spatial arrival differences of the simulated signal after propagation through different paths. Especially in high frequency bands (such as 60 GHz) and strong metal reflection scenarios, the superposition characteristics of multipath signals are significant, and the propagation path is significantly constrained by the physical structure (such as medium diffraction and metal interface reflection). Existing simulation technologies are mostly based on digital domain algorithms (such as FPGA or ASIC) to simulate the multipath superposition effect at the baseband end. Its output depends on idealized mathematical models and cannot truly reflect the actual propagation behavior of RF signals in physical links. It is especially difficult to simulate the dynamic characteristics of path-related delays caused by structural limitations in metal cavities. Therefore, how to achieve dynamic, adjustable and precise control of physical-level delay spread through hardware devices is a difficulty that needs to be solved in the field of channel simulation. Summary of the invention

[0004] The purpose of the embodiment of the present invention is to provide a signal multipath effect simulation system to solve the technical problems of limited real-time performance and simulation accuracy of digital signal simulation systems in the prior art.

[0005] To achieve the above object, the technical solution adopted by the present invention is: to provide a signal multipath effect simulation system, comprising:

[0006] A radio frequency signal generator, used for sending a radio frequency signal;

[0007] A power divider for dividing the radio frequency signal into multiple signals;

[0008] A plurality of signal simulation devices, the multiple signals are respectively input to the corresponding signal simulation devices, each of the signal simulation devices is used to simulate signals with different time delays, the signal simulation device includes an amplitude controller and a single-signal simulator connected in transmission, the amplitude controller is used to control the amplitude of the signal, the single-signal simulator includes a time-delay control board, a waveguide transmission structure and a radio frequency switch, the waveguide transmission structure includes a plurality of transmission paths, the lengths of each of the transmission paths are different, the radio frequency switch is used to selectively conduct each of the transmission paths, and the radio frequency switch and at least a part of the transmission paths are both arranged on the time-delay control board;

[0009] A power combiner, connected in transmission with the plurality of signal simulation devices, for combining the output signals of the plurality of signal simulation devices;

[0010] A signal receiver for converting the combined signal into a time-delay power distribution.

[0011] Optionally, the waveguide transmission structure includes multiple sections of grounded coplanar waveguides, adjacent two sections of the grounded coplanar waveguides are both connected through the radio frequency switch, and at least two sections of the grounded coplanar waveguides are arranged in parallel.

[0012] Optionally, the waveguide transmission structure includes a plurality of first transmission units connected in series, the first transmission unit includes a first grounded coplanar waveguide and a second grounded coplanar waveguide connected in parallel, and the first end of the first grounded coplanar waveguide and the first end of the second grounded coplanar waveguide are connected through the radio frequency switch, the second end of the first grounded coplanar waveguide and the second end of the second grounded coplanar waveguide are connected through the radio frequency switch, so that the first grounded coplanar waveguide and the second grounded coplanar waveguide are selectively conducted, and the lengths of the first grounded coplanar waveguide and the second grounded coplanar waveguide are different.

[0013] Optionally, adjacent two of the first transmission units are connected through a transmission connection waveguide, and both ends of the transmission connection waveguide are respectively connected to the radio frequency switches of the two first transmission units.

[0014] Optionally, in each of the first transmission units, the length difference between the second grounded coplanar waveguide and the first grounded coplanar waveguide is a geometric progression.

[0015] Optionally, the waveguide transmission structure further includes a plurality of second transmission units connected in series, the first transmission unit and the second transmission units are connected in series, the second transmission unit includes a third grounded coplanar waveguide, two fourth grounded coplanar waveguides, and a rectangular waveguide. The two ends of the third grounded coplanar waveguide are respectively connected to the first ends of the two fourth grounded coplanar waveguides through the RF switches, and the second ends of the two fourth grounded coplanar waveguides are both coupled to the rectangular waveguide, so that the rectangular waveguide and the third grounded coplanar waveguide are selectively conducted, and the lengths of the transmission channels of the respective rectangular waveguides are different.

[0016] Optionally, the interior of the rectangular waveguide has the hollow transmission channel, both ends of the transmission channel have coupling windows, the two coupling windows are located on the same side wall of the rectangular waveguide, and the two coupling windows are respectively opposite to the second ends of the two fourth grounded coplanar waveguides.

[0017] Optionally, the rectangular waveguide includes a first metal plate and a second metal plate. The first metal plate is provided with a first groove, the second metal plate is provided with a second groove, the first metal plate and the second metal plate are fixedly connected by fastening screws, and the first groove and the second groove are oppositely arranged to form the transmission channel.

[0018] Optionally, the rectangular waveguide is vertically arranged on the time delay control board, and the respective rectangular waveguides are arranged at intervals in sequence along their thickness directions. A reinforcing plate is arranged at a position where the plurality of rectangular waveguides are away from the time delay control board, and the reinforcing plate is fixed to the plurality of rectangular waveguides.

[0019] Optionally, the single-signal simulator further includes a radar chip. A signal transmitting end and a signal receiving end are arranged on the time delay control board. The waveguide transmission structure is located between the signal transmitting end and the signal receiving end, and the radar chip is also connected between the signal transmitting end and the signal transmitting end.

[0020] The beneficial effects of the signal multipath effect simulation system provided by the present invention are as follows: Compared with the prior art, the signal multipath effect simulation system of the present invention includes a radio frequency signal generator, a power divider, a plurality of signal simulation devices, a power combiner, and a signal receiver. Each signal simulation device is used to simulate signals with different time delays. Each signal simulation device includes an amplitude controller and a single-signal simulator. The single-signal simulator includes a time delay control board, a waveguide transmission structure composed of a plurality of transmission paths, and a radio frequency switch. The lengths of the respective transmission paths are different. After the power divider decomposes the signal into multiple paths of signals, each path of signal is attenuated to different amplitudes by the amplitude controller, and then forms a corresponding time delay through the single-signal simulator. Moreover, the single-signal simulator can switch different transmission paths through the radio frequency switch, so different time delays can be correspondingly formed. The power combiner linearly superimposes the multiple paths of signals with time delays, and the signal receiver obtains the complete time delay power distribution characteristics, thereby reproducing the time delay power distribution law of the simulated real environment. Through the coordinated operation of multiple single-channel simulators, the system can simulate the multipath effect in a complex channel environment in real time and accurately, and provide high-precision channel characteristic simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 It is a schematic structural diagram of the signal multipath effect simulation system provided by the embodiment of the present invention;

[0023] Figure 2 It is a schematic structural diagram of the time delay control board provided by the embodiment of the present invention;

[0024] Figure 3 It is a schematic structural diagram of the single-signal simulator provided by the embodiment of the present invention;

[0025] Figure 4 It is a schematic structural diagram of the switch control board provided by the embodiment of the present invention.

[0026] Among them, the reference numerals in the drawings:

[0027] 10 - Delay control board; 11 - Signal transmitting end; 12 - Signal receiving end; 20 - Waveguide transmission structure; 21 - First transmission unit; 211 - First grounded coplanar waveguide; 212 - Second grounded coplanar waveguide; 22 - Second transmission unit; 221 - Third grounded coplanar waveguide; 222 - Fourth grounded coplanar waveguide; 2221 - Coupling part; 223 - Rectangular waveguide; 2231 - Transmission channel; 2232 - Fastening screw; 23 - Transmission connection waveguide; 30 - RF switch; 40 - Reinforcement plate; 50 - Switch control board; 51 - Control unit. Detailed implementation mode

[0028] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0030] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0031] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0032] Currently, channel simulation technologies are mainly divided into two categories: digital signal processing solutions and radio frequency hardware reconstruction solutions. The digital signal processing solution combines mathematical models and channel theory, and uses algorithms to accurately simulate factors such as time delay, frequency offset, and Doppler effect in the wireless channel, which has become the mainstream simulation technology. Its advantage lies in strong flexibility, capable of finely controlling channel characteristics in software, and applicable to the simulation of various complex wireless environments. Although the digital signal processing solution can provide high accuracy and flexibility, its simulation real-time performance and physical signal reconstruction ability are relatively limited.

[0033] In contrast, the radio frequency hardware reconstruction solution dynamically adjusts the time delay, frequency, and other channel characteristics of the signal through actual hardware devices, and can more realistically reproduce the multipath effect and other physical characteristics in the complex channel. This method can simulate the wireless signal propagation in high-frequency and large-bandwidth environments, and is applicable to scenarios that require extremely high signal authenticity and real-time response, such as 5G communication and satellite communication, etc.

[0034] The current defects of channel simulation technologies are as follows:

[0035] 1. Lack of real reconstruction of physical signals: Most of the current channel simulation technologies rely on digital signal processing and mathematical models. Although they can simulate time delay and frequency changes, it is difficult to fully restore the physical transmission characteristics of signals in the real environment, especially in terms of multipath effect and non-linear signal processing.

[0036] 2. Limitations in real-time performance and accuracy: Digital signal simulation systems usually require a large amount of calculations to simulate channel changes. As the signal complexity increases, the real-time performance and accuracy may be limited. Especially in high-dynamic channel tests, digital models may not be able to provide sufficient fast response and accurate simulation.

[0037] 3. Large device volume and poor versatility: Traditional channel simulators are usually large in volume, lack flexibility, and have strong specificity, making it difficult to meet the requirements of portability and multi-scenario adaptability. This limits the application of the device in actual scenarios to a certain extent.

[0038] 4. High cost and maintenance burden: Many channel simulation systems are costly, especially devices that rely on high-power signal sources and complex measurement modules. Not only is the purchase cost high, but the later maintenance and use are also relatively onerous, increasing the economic pressure of R & D and testing.

[0039] 5. Limited high-frequency band simulation ability: In high-frequency applications (such as millimeter wave or higher frequency bands), existing digital simulation devices may be difficult to accurately simulate the signal attenuation and time delay distribution, restricting their application in modern communication and complex environment tests.

[0040] Compared with the digital channel simulation scheme in the related art, the present application has more realistic physical signal simulation capabilities, lower costs, and smaller volumes, and has more advantages in the simulation accuracy of high frequency bands and multipath effects.

[0041] Multipath effect refers to the phenomenon that in a wireless channel, the transmitted signal reaches the receiving end through multiple propagation paths. Due to the different propagation distances of these paths and the environment, the signal will experience different paths when reaching the receiving end, and thus different time delays, phases, and amplitudes will be generated, resulting in signal superposition, interference, or attenuation. Multipath effects can cause problems such as signal fading, delay spread, and frequency-selective fading, and are one of the main factors affecting wireless communication performance.

[0042] The signal multipath effect simulation system provided by the embodiments of the present invention will now be described. In a complex environment, after the signal is emitted from the transmitting end, it will not propagate along a single propagation path. Usually, it will propagate along multiple paths to the receiving end. During the propagation process, the signal will exhibit characteristics such as amplitude attenuation, phase change, and time delay. In order to better study the characteristics of signal multipath transmission, the present invention proposes a signal multipath effect simulation system to simulate the amplitude attenuation, time delay (time delay), etc. of the signal passing through multiple propagation paths from the transmitting end to the receiving end.

[0043] Please refer to Figure 1 and Figure 2 , the signal multipath effect simulation system includes:

[0044] A radio frequency signal generator for emitting radio frequency signals;

[0045] A power splitter for dividing the radio frequency signal into multiple signals;

[0046] Multiple signal simulation devices, and the multiple signals are respectively input into the corresponding signal simulation devices. Each signal simulation device is used to simulate signals with different time delays. The signal simulation device includes an amplitude controller and a single-signal simulator connected in transmission. The amplitude controller is used to control the amplitude of the signal. The single-signal simulator includes a time delay control board 10, a waveguide transmission structure 20, and a radio frequency switch 30. The waveguide transmission structure 20 includes multiple transmission paths, and the lengths of each transmission path are different. The radio frequency switch 30 is used to selectively conduct each transmission path. The radio frequency switch 30 and at least some of the transmission paths are both provided on the time delay control board 10;

[0047] A power combiner, which is connected in transmission with multiple signal simulation devices and is used to combine the output signals of the multiple signal simulation devices;

[0048] A signal receiver for converting the combined signal into a time delay power distribution.

[0049] The radio frequency signal generator is used to generate and transmit radio frequency signals at various frequencies. The radio frequency signals can be electromagnetic waves, such as frequency modulated continuous waves, etc. The power divider, also known as the power splitter, is a device that divides the energy of an input signal into two or more output signals with equal or unequal energies. When the power divider divides the radio frequency signal into multiple signals, the multiple signals can be the same signal or different signals.

[0050] The signal simulation device is used to simulate the propagation characteristics of a signal on a certain propagation path (the propagation path corresponding to a certain time delay), or to simulate the propagation characteristics of a signal on similar propagation paths (the propagation paths corresponding to a certain time delay segment). Multiple signal simulation devices can simulate the propagation characteristics of all or nearly all propagation paths. The signal simulation device includes an amplitude controller and a single-signal simulator connected in transmission. Transmission connection means that signals can be transmitted between the two. For example, the amplitude controller can be connected to the single-signal simulator in series. The amplitude controller is used to control the amplitude of the input signal and control the amplitude of the input signal according to the attenuation amplitude of the signal in each actual propagation path. In this way, the attenuation of the signal amplitude after passing through the propagation path can be simulated by the amplitude controller, and the time delay of the signal after passing through one of the propagation paths can be simulated by the single-signal simulator. The single-signal simulator includes a time delay control board 10, a waveguide transmission structure 20, and a radio frequency switch 30. The waveguide transmission structure 20 and the radio frequency switch 30 are both arranged on the time delay control board 10. The time delay control board 10 can be understood as a kind of circuit board. The setting of the waveguide transmission structure 20 is used to simulate the time delay of the signal during transmission. The waveguide transmission structure 20 includes multiple transmission paths, and the lengths of the respective transmission paths are different, and the time required for the signal to pass through each transmission path is also different. Therefore, in each different single-signal simulator, one transmission path can correspond to simulating the time delay of one propagation path. The radio frequency switch 30 is used to selectively conduct each transmission path, which means that the radio frequency switch 30 can control the waveguide transmission structure 20 to make each transmission path conduct different transmission paths in different states to simulate the time delay of the corresponding propagation path.

[0051] The power combiner is used to combine the output signals of multiple signal simulation devices. The combined signal is called the combined signal. The signal receiver is used to convert the above combined signal into a time delay power distribution. The time delay power distribution refers to the power magnitude corresponding to each time delay, and can also be understood as a distribution diagram with the time delay as the abscissa and the power corresponding to the time delay as the ordinate. The time delay power distribution is convenient for analyzing wireless signals.

[0052] The working principle of the signal multipath effect simulation system is as follows: The RF signal generator emits RF signals. The signals are decomposed into multiple paths by a power divider, and each path of the signal is transmitted to a different signal simulation device correspondingly. In the signal simulation device, the amplitude of the signal is changed by an amplitude controller to simulate the amplitude attenuation during signal transmission, and then the time delay generated during signal transmission is simulated by a single-signal simulator. Each single-signal simulator can simulate the propagation path corresponding to different time delays by changing its transmission path. Correspondingly, multiple signal simulation devices respectively simulate the signals of different propagation paths.

[0053] The signal multipath effect simulation system in the above embodiment includes an RF signal generator, a power divider, multiple signal simulation devices, a power combiner, and a signal receiver. Each signal simulation device is used to simulate signals with different time delays. Each signal simulation device includes an amplitude controller and a single-signal simulator. The single-signal simulator includes a time delay control board 10, a waveguide transmission structure 20 composed of multiple transmission paths, and an RF switch 30. The lengths of the respective transmission paths are different. After the power divider decomposes the signal into multiple paths, each path of the signal is attenuated to different amplitudes by the amplitude controller, and then the corresponding time delay is formed through the single-signal simulator. Moreover, the single-signal simulator can switch different transmission paths through the RF switch 30, so different time delays can be correspondingly formed. The power combiner linearly superimposes the multiple paths of signals with time delays, and the complete time delay power distribution characteristic is obtained through the signal receiver, thereby reproducing the time delay power distribution law of the simulated real environment. Through the coordinated work of multiple single-channel simulators, the system can simulate the multipath effect in a complex channel environment in real time and accurately, and provide high-precision channel characteristic simulation.

[0054] In some embodiments of the present invention, please refer to Figure 2 , the waveguide transmission structure 20 includes multiple sections of grounded coplanar waveguides. Adjacent two sections of grounded coplanar waveguides are connected through the RF switch 30, and at least two sections of grounded coplanar waveguides are arranged in parallel. The grounded coplanar waveguide is a microwave waveguide transmission structure commonly used in high-frequency circuits, generally composed of a center signal line, symmetric ground planes, and metallized vias on both sides. The signal propagates along the center signal line, and the electromagnetic energy is effectively restricted between the center signal line and the ground plane. The grounded coplanar waveguide has low radiation loss, good impedance matching, and excellent high-frequency performance, and is widely used in millimeter-wave RF circuits and is suitable for high-density and high-performance communication systems. Specifically, in this embodiment, the grounded coplanar waveguide includes a center signal line and two ground lines located on both sides of the center signal line. The center signal line and the ground lines are both located on the front side of the time delay control board 10, and the two ground lines are conducted to the metal ground on the back side of the time delay control board 10 through metal vias. At least two sections of grounded coplanar waveguides are arranged in parallel, so that one of the grounded coplanar waveguides can be selectively controlled to be conducted through the RF switch 30.

[0055] Optionally, the first end of one grounded coplanar waveguide is connected to the first end of another grounded coplanar waveguide through a radio frequency switch 30, and the second end of one grounded coplanar waveguide is connected to the second end of another grounded coplanar waveguide through a radio frequency switch 30.

[0056] In some embodiments of the present invention, please refer to Figure 2 , the waveguide transmission structure 20 includes a plurality of first transmission units 21 connected in series. The first transmission unit 21 includes a first grounded coplanar waveguide 211 and a second grounded coplanar waveguide 212 connected in parallel. The first end of the first grounded coplanar waveguide 211 is connected to the first end of the second grounded coplanar waveguide 212 through a radio frequency switch 30, and the second end of the first grounded coplanar waveguide 211 is connected to the second end of the second grounded coplanar waveguide 212 through a radio frequency switch 30, so that the first grounded coplanar waveguide 211 and the second grounded coplanar waveguide 212 are selectively conducted. The lengths of the first grounded coplanar waveguide 211 and the second grounded coplanar waveguide 212 are different. The signal can be conducted from the first grounded coplanar waveguide 211 through the radio frequency switch 30, or from the second grounded coplanar waveguide 212. Since the lengths of the first grounded coplanar waveguide 211 and the second grounded coplanar waveguide 212 are different, the transmission time of the signal in the first grounded coplanar waveguide 211 and the second grounded coplanar waveguide 212 is different. By selecting different grounded coplanar waveguides, the delay signal simulated by a single signal simulator can be changed. When two adjacent first transmission units 21 are connected in series, the radio frequency switches 30 of the two first transmission units 21 are connected to each other.

[0057] By providing a plurality of first transmission units 21 and selecting the corresponding grounded coplanar waveguide to be conducted in each first transmission unit 21, it is convenient to achieve stepped delay control and realize as many different delays as possible with a small number of grounded coplanar waveguides. Such a design also enables high-precision signal delay adjustment and can adapt to the stable transmission of high-frequency signals.

[0058] In some embodiments, please refer to Figure 2 , two adjacent first transmission units 21 are connected through a transmission connection waveguide 23. The two ends of the transmission connection waveguide 23 are respectively connected to the radio frequency switches 30 of the two first transmission units 21. The transmission connection waveguide 23 is used to connect two first transmission units 21 and is also a grounded coplanar waveguide. When two grounded coplanar waveguides are conducted through the radio frequency switch 30, the center signal lines of the two grounded coplanar waveguides are conducted with each other, and the wiring lines of the two grounded coplanar waveguides are correspondingly conducted.

[0059] By providing the transmission connection waveguide 23, it is more convenient to layout a plurality of first transmission units 21 and reduce the mutual coupling and other influences between adjacent first transmission units 21.

[0060] In some embodiments of the present invention, please refer to Figure 2 , in each of the first transmission units 21, the length difference between the second ground coplanar waveguide 212 and the first ground coplanar waveguide 211 forms a geometric sequence. The length difference between each second ground coplanar waveguide 212 and the corresponding first ground coplanar waveguide 211 is , where p is a constant, and n is a positive integer. For the convenience of description, the length difference between the second ground coplanar waveguide 212 and the first ground coplanar waveguide 211 of the first transmission unit 21 can be simply referred to as the transmission distance difference of the first transmission unit 21.

[0061] By setting the transmission distance difference of the first transmission unit 21 as a geometric sequence, it is easier for a single-signal simulator to achieve stepwise adjustment of the time delay.

[0062] In some embodiments, please refer to Figure 2 , through full-wave simulation analysis, the electromagnetic wave transmission time delay of the ground coplanar waveguide is approximately 20 cm / ns. The number of the first transmission units 21 is 3. The three first transmission units 21 are named the No. 1 first transmission unit 21, the No. 2 first transmission unit 21, and the No. 3 first transmission unit 21 from left to right. The transmission distance difference of the No. 1 first transmission unit 21 is 5 cm, the transmission distance difference of the No. 2 first transmission unit 21 is 10 cm, and the transmission distance difference of the No. 3 first transmission unit 21 is 20 cm. Thus, by switching between the first ground coplanar waveguide 211 and the second ground coplanar waveguide 212 in the No. 1 first transmission unit 21, a time delay of 0.25 ns can be generated; by switching between the first ground coplanar waveguide 211 and the second ground coplanar waveguide 212 in the No. 2 first transmission unit 21, a time delay of 0.5 ns can be generated; by switching between the first ground coplanar waveguide 211 and the second ground coplanar waveguide 212 in the No. 3 first transmission unit 21, a time delay of 1 ns can be generated.

[0063] In some embodiments of the present invention, please refer to Figure 3, the waveguide transmission structure 20 further includes a plurality of second transmission units 22 connected in series. The first transmission unit 21 and the second transmission units 22 are connected in series. The second transmission unit 22 includes a third grounded coplanar waveguide 221, two fourth grounded coplanar waveguides 222, and a rectangular waveguide 223. The two ends of the third grounded coplanar waveguide 221 are respectively connected to the first ends of the two fourth grounded coplanar waveguides 222 through radio frequency switches 30. The second ends of the two fourth grounded coplanar waveguides 222 are both coupled to the rectangular waveguide 223, enabling the rectangular waveguide 223 and the third grounded coplanar waveguide 221 to be selectively conducted. The lengths of the transmission channels 2231 of the respective rectangular waveguides 223 are different. The number of the first transmission units 21 and the second transmission units 22 is plural. The first transmission units 21 and the second transmission units 22 are connected in series, and the following situations are possible: a plurality of first transmission units 21 are connected in series in sequence, a plurality of second transmission units 22 are connected in series in sequence, and then the two are connected in series together; the first transmission units 21 and the second transmission units 22 can also be connected in series alternately. Through the setting of the radio frequency switches 30, the rectangular waveguide 223 is connected in parallel with the fourth grounded coplanar waveguide 222 and the third grounded coplanar waveguide 221. When the radio frequency switch 30 conducts the rectangular waveguide 223, the two fourth grounded coplanar waveguides 222 and the rectangular waveguide 223 serve as part of the transmission path. When the radio frequency switch 30 conducts the third grounded coplanar waveguide 221, the third grounded coplanar waveguide 221 is part of the transmission path.

[0064] Due to the limited area of the delay control board 10 and the limited length of the grounded coplanar waveguide, it is difficult to expand the delay adjustment range of a single signal simulator within the limited area. Therefore, through the coupling of the grounded coplanar waveguide and the rectangular waveguide 223, the rectangular waveguide 223 is used as part of the transmission path to increase the delay adjustment range of a single signal simulator. Moreover, the lengths of the transmission channels 2231 of the respective rectangular waveguides 223 are different, which can further increase the delay adjustment range of a single signal simulator.

[0065] In some embodiments, please refer to Figure 3, through full-wave simulation analysis, the electromagnetic wave transmission delay of the rectangular waveguide 223 is approximately 20 cm / ns. The number of the second transmission units 22 is 4. The three second transmission units 22 are named as the No. 1 second transmission unit 22, the No. 2 second transmission unit 22, the No. 3 second transmission unit 22, and the No. 4 second transmission unit 22 from right to left in sequence. For the convenience of description, the value obtained by subtracting the length of the third grounded coplanar waveguide 221 from the sum of the lengths of the two fourth grounded coplanar waveguides 222 and the transmission channel 2231 of the rectangular waveguide 223 can be called the transmission distance difference of the second transmission unit 22. The transmission distance difference of the No. 1 second transmission unit 22 is 40 cm, the transmission distance difference of the No. 2 first transmission unit 21 is 80 cm, the transmission distance difference of the No. 3 first transmission unit 21 is 160 cm, and the transmission distance difference of the No. 4 first transmission unit 21 is 320 cm. Thus, by switching between the two transmission paths in the No. 1 second transmission unit 22, a delay of 2 ns can be generated; by switching between the two transmission paths in the No. 2 second transmission unit 22, a delay of 4 ns can be generated; by switching between the two transmission paths in the No. 3 second transmission unit 22, a delay of 8 ns can be generated; by switching between the two transmission paths in the No. 4 second transmission unit 22, a delay of 16 ns can be generated.

[0066] Through the collaborative work between 3 first transmission units 21 and 4 second transmission units 22, and the cascaded combination of 14 radio frequency switches 30, it is intended to achieve delay regulation with an accuracy of 0.25 ns in the range of 0 to 31.75 ns. The role of the radio frequency switch 30 is to flexibly switch the signal path, ensuring that the signal dynamically switches between different paths according to needs, so as to achieve precise signal delay control.

[0067] In some embodiments, the lowest frequency of the signal multipath effect simulation system is 60 GHz, the highest frequency is 64 GHz, the working bandwidth is 4 GHz, the single-signal delay regulation range is 0 to 31.75 ns, and the step is 0.25 ns.

[0068] In some embodiments of the present invention, please refer to Figure 4 , Figure 4 For the structural diagram of the switch control board 50, each radio frequency switch 30 is controlled by the switch control board 50, so as to realize the control and switching of the transmission path in the single-signal simulator.

[0069] In some embodiments, the switch control board 50 can be a GPIO control board, and the control unit 51 on the switch control board 50 is an STM32 MCU.

[0070] In some embodiments, the radio frequency switch 30 is an ADRF5032 chip.

[0071] In some embodiments of the present invention, please refer to Figure 3 , the interior of the rectangular waveguide 223 has a hollow transmission channel 2231. Both ends of the transmission channel 2231 have coupling windows. The two coupling windows are located on the same side wall of the rectangular waveguide 223, and the two coupling windows are respectively opposite to the second ends of the two fourth grounded coplanar waveguides 222. The rectangular waveguide 223 is a metal structure, and the inner wall of the formed transmission channel 2231 is equivalent to a metal shell, and signals can be transmitted within the transmission channel 2231. The rectangular waveguide 223 has six different side walls. The two coupling windows are located on the same side wall of the rectangular waveguide 223, and one coupling window is coupled to the second end of one fourth grounded coplanar waveguide 222. Combining Figure 3 , both of the two coupling windows are located on the bottom wall of the rectangular waveguide 223. Among the two coupling windows, one coupling window is a signal input window, and the other window is a signal output window.

[0072] The two coupling windows are arranged on the same side wall of the rectangular waveguide 223, and the second ends of the two fourth grounded coplanar waveguides 222 are also located on the same surface (the front surface of the time delay control board 10). In this way, both ends of the transmission channel 2231 of the rectangular waveguide 223 can be closely arranged with the second ends of the two fourth grounded coplanar waveguides 222 respectively, realizing the coupled transmission between the rectangular waveguide 223 and the fourth grounded coplanar waveguide 222.

[0073] In some embodiments, please refer to Figure 3 , the transmission channel 2231 is arched, and the length of the transmission channel 2231 can be increased within a limited area.

[0074] In some embodiments, please refer to Figure 2 and Figure 3 , one end of the fourth grounded coplanar waveguide 222 away from the RF switch 30 has a coupling portion 2221 made of metal. The coupling portion 2221 is located on the front surface of the time delay control board 10. A hollow hole is opened at the center of the coupling portion 2221. The coupling window of the rectangular waveguide 223 is arranged opposite to the hollow hole. The ground wire of the fourth grounded coplanar waveguide 222 is connected to the coupling portion 2221. The center line of the fourth grounded coplanar waveguide 222 extends to be close to the coupling portion 2221 and is spaced from the coupling portion 2221. An extension line and a feeding portion are arranged on the back surface of the time delay control board 10. One end of the extension line is connected to one end of the center line of the fourth grounded coplanar waveguide 222 through a metal via hole, and the other end of the extension line is connected to the feeding portion. The feeding portion is arranged opposite to the hollow hole and is used to realize the coupled feeding between the fourth grounded coplanar waveguide 222 and the rectangular waveguide 223.

[0075] In some embodiments of the present invention, please refer to Figure 3, the rectangular waveguide 223 includes a first metal plate and a second metal plate. The first metal plate is provided with a first groove, and the second metal plate is provided with a second groove. The first metal plate and the second metal plate are fixedly connected by fastening screws 2232, and the first groove and the second groove are arranged opposite to each other to form a transmission channel 2231. The extending directions of the first groove and the second groove are the same as the extending direction of the transmission channel 2231. The side of the first metal plate having the first groove is closely attached to the side of the second metal plate having the second groove, so that the first groove and the second groove jointly form the transmission channel 2231.

[0076] By dividing the rectangular waveguide 223 into a first metal plate and a second metal plate, it is more convenient to process the transmission channel 2231. Compared with hollowing out the inside of a whole metal plate to form a transmission channel, the process of processing grooves on two metal plates respectively is simpler and the cost is higher. By fixedly connecting the first metal plate and the second metal plate with the fastening screws 2232, not only can the two metal plates be fixed, but also the two metal plates can be closely attached to each other. The transmission channel 2231 is a structurally complete channel to avoid affecting the transmission of signals in the transmission channel 2231.

[0077] In some embodiments, a plurality of fastening screws 2232 are sequentially and spacedly distributed along the extending direction of the transmission channel 2231. Moreover, both sides of the transmission channel 2231 in its width direction are provided with fastening screws 2232, so as to reduce the gap between the first metal plate and the second metal plate and reduce the gap between the inner walls of the transmission channel 2231.

[0078] In some embodiments of the present invention, please refer to Figure 3 , the rectangular waveguide 223 is vertically arranged on the time delay control board 10, and the rectangular waveguides 223 are sequentially and spacedly arranged along their thickness directions. A reinforcing plate 40 is arranged at a position where the plurality of rectangular waveguides 223 are far away from the time delay control board 10, and the reinforcing plate 40 is fixed to the plurality of rectangular waveguides 223. The rectangular waveguide 223 is vertically arranged on the time delay control board 10. It can be understood that the thickness direction of the rectangular waveguide 223 is perpendicular to the thickness direction of the time delay control board 10, which is equivalent to the rectangular waveguide 223 "standing" on the time delay control board 10. For the convenience of description, when the time delay control board 10 is located on the horizontal plane, it is used as a direction reference for description. The end of the rectangular waveguide 223 far away from the time delay control board 10 is the top end of the rectangular waveguide 223. The position where the plurality of rectangular waveguides 223 are far away from the time delay control board 10 can be understood as the middle-lower part, middle part, middle-upper part, top part, etc. of the rectangular waveguide 223 in the height direction. The reinforcing plate 40 can be fixed to the middle part of the vertical side wall, the middle-lower part of the vertical side wall, the middle-upper part of the vertical side wall, the top wall, etc. of the rectangular waveguide 223. When the height of the rectangular waveguide 223 is relatively high, the rectangular waveguide 223 is prone to shaking, resulting in the problem of unstable coupling connection. Through the arrangement of the reinforcing plate 40, the connection between each rectangular waveguide 223 and the time delay control board 10 can be made more stable.

[0079] In some embodiments of the present invention, refer to Figure 2 , the single-signal simulator further includes a radar chip. A signal transmitting end 11 and a signal receiving end 12 are provided on the time delay control board 10. The waveguide transmission structure 20 is located between the signal transmitting end 11 and the signal receiving end 12. A radar chip is also connected between the signal transmitting end 11 and the signal transmitting end 11. The amplitude controller outputs the signal after amplitude adjustment to the time delay control board 10. The time delay control is performed through the waveguide transmission structure 20 on the time delay control board 10. At the same time, the signal after amplitude adjustment is transmitted from the signal transmitting end 11 of the time delay control board 10 to the radar chip. The signal output end of the time delay control board 10 outputs the delayed signal to the radar chip. In this way, the time delay and amplitude generated by the signal passing through the time delay control board 10 can be detected by the radar chip.

[0080] Combined with Figure 2 , in each signal simulation device, the amplitude controller is named A n , the single-signal simulator is named M n , RX n is the signal obtained by each signal receiving end 12 (used to simulate the signals of each propagation path), and n is a positive integer greater than or equal to 2. Each RX n is synthesized through a power combiner to obtain RX total , and then the time delay power distribution (the coordinate diagram between the power combiner and the receiver) is obtained.

[0081] In some embodiments of the present invention, the signal multipath effect simulation system further includes a PC, which is connected to the signal receiver and is used to input instructions or output and display the time delay power distribution. The PC can be understood as a computer.

[0082] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A signal multipath effect simulation system, characterized in that: include: A radio frequency signal generator, used for sending a radio frequency signal; A power divider, used for dividing the radio frequency signal into multiple signals; A plurality of signal simulation devices, wherein a plurality of signals are respectively input to the corresponding signal simulation devices, each of which is used to simulate signals with different delays, wherein the signal simulation device comprises an amplitude controller and a single signal simulator of a transmission connection, wherein the amplitude controller is used to control the amplitude of the signal, and the single signal simulator comprises a delay control board, a waveguide transmission structure and a radio frequency switch, wherein the waveguide transmission structure comprises a plurality of transmission paths, wherein the lengths of the respective transmission paths are different, and the radio frequency switch is used to selectively conduct the respective transmission paths, and the radio frequency switch and at least part of the transmission paths are both arranged on the delay control board; the waveguide transmission structure comprises a plurality of first transmission units connected in series, wherein the first transmission unit comprises a first grounded coplanar waveguide and a second grounded coplanar waveguide connected in parallel, and the first end of the first grounded coplanar waveguide is connected to the first end of the second grounded coplanar waveguide via the radio frequency switch, and the second end of the first grounded coplanar waveguide is connected to the second end of the second grounded coplanar waveguide via the radio frequency switch The waveguide transmission structure further comprises a plurality of second transmission units connected in series, wherein the first transmission unit and the second transmission unit are connected in series, and the second transmission unit comprises a third grounded coplanar waveguide, two fourth grounded coplanar waveguides and a rectangular waveguide, and the two ends of the third grounded coplanar waveguide are respectively connected to the first ends of the two fourth grounded coplanar waveguides through the RF switch, and the second ends of the two fourth grounded coplanar waveguides are coupled to the rectangular waveguide, so that the rectangular waveguide and the third grounded coplanar waveguide are selectively connected, and the transmission channels of the rectangular waveguides have different lengths; the rectangular waveguide has a hollow transmission channel inside, and both ends of the transmission channel have coupling windows, and the two coupling windows are located on the same side wall of the rectangular waveguide, and the two coupling windows are respectively opposite to the second ends of the two fourth grounded coplanar waveguides; A power synthesizer, connected to the plurality of signal simulation devices for synthesizing output signals of the plurality of signal simulation devices; A signal receiver is used to convert the composite signal into a time-delay power distribution.

2. The signal multipath effect simulation system as claimed in claim 1, characterized in that: The waveguide transmission structure includes multiple sections of grounded coplanar waveguides, two adjacent sections of the grounded coplanar waveguides are connected through the radio frequency switch, and at least two sections of the grounded coplanar waveguides are arranged in parallel.

3. The signal multipath effect simulation system as claimed in claim 1, characterized in that: Two adjacent first transmission units are connected via a transmission connection waveguide, and two ends of the transmission connection waveguide are respectively connected to the radio frequency switches of the two first transmission units.

4. The signal multipath effect simulation system as claimed in claim 1, characterized in that: In each of the first transmission units, a length difference between the second grounded coplanar waveguide and the first grounded coplanar waveguide is a geometric progression.

5. The signal multipath effect simulation system as claimed in claim 1, characterized in that: The rectangular waveguide includes a first metal plate and a second metal plate, the first metal plate is provided with a first groove, the second metal plate is provided with a second groove, the first metal plate and the second metal plate are fixedly connected by fastening screws, and the first groove and the second groove are arranged opposite to each other to form the transmission channel.

6. The signal multipath effect simulation system as claimed in claim 1, characterized in that: The rectangular waveguide is vertically arranged on the delay control board, and each of the rectangular waveguides is arranged in sequence along the thickness direction thereof. A reinforcement plate is arranged at a position of the plurality of rectangular waveguides away from the delay control board, and the reinforcement plate is fixed to the plurality of rectangular waveguides.

7. The signal multipath effect simulation system according to any one of claims 1 to 6, characterized in that: The single signal simulator also includes a radar chip. A signal transmitting end and a signal receiving end are provided on the delay control board. The waveguide transmission structure is located between the signal transmitting end and the signal receiving end. The radar chip is also connected between the signal transmitting end and the signal transmitting end.

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