Multi-aperture high-gain antenna structure based on millimeter wave radar and detection enhancement method

Abstract

The application discloses a multi-aperture high-gain antenna structure based on a millimeter wave radar and a detection enhancement method, which is suitable for a 77GHz frequency band and a 92GHz roadside millimeter wave radar scene. The high-gain antenna structure comprises a millimeter wave radio frequency unit, a multi-aperture antenna array, a synchronous phase feed network, a beam control module and a signal synthesis processing unit. The multi-aperture antenna array is arranged by multiple groups of different specification sub-aperture antenna units according to a preset spatial layout, so as to form an equivalent large radiation aperture. The synchronous phase feed network realizes synchronous excitation and phase calibration of sub-aperture signals. The beam control module controls and regulates a beam direction and suppresses a sidelobe. The signal synthesis processing unit coherently superimposes and suppresses noise of multiple received signals. The application realizes the enhanced detection effect of the high-gain antenna structure through multi-aperture cooperative arraying, synchronous phase feeding, differentiated beam optimization, signal coherent synthesis and special plate and feed structure design.

Description

Technical Field

[0001] This invention relates to the field of millimeter-wave radar antenna technology, specifically to a multi-aperture high-gain antenna structure and detection enhancement method based on millimeter-wave radar. Background Technology

[0002] Millimeter-wave radar has become a core sensing device in fields such as intelligent transportation, intelligent driving, security monitoring, and industrial inspection due to its all-weather and all-time operation capability and its immunity to adverse environmental factors such as rain, fog, and dust. Common operating frequency bands for millimeter-wave radar include 24GHz, 77GHz-79GHz, 80GHz, and 92GHz-94GHz. Among them, the 92GHz band has become the new mainstream choice for roadside long-range millimeter-wave radar due to its wide bandwidth and high resolution.

[0003] Currently, most millimeter-wave radar antennas adopt single-aperture or simple array structures, which have many technical shortcomings in practical engineering applications, especially in roadside long-range detection scenarios, where the deficiencies are more prominent. Specifically, these shortcomings are as follows:

[0004] 1. Due to its low antenna gain and limited radiation aperture, traditional single-aperture antennas struggle to achieve stable detection over distances of 500m. Furthermore, the angular resolution is limited by the number of antenna elements, making it impossible to meet the requirements for high-precision speed and distance measurement on the roadside.

[0005] 2. The echo signals of long-range targets and targets with low radar cross-sections are weak and easily drowned out by environmental noise, resulting in low target detection probability, poor tracking continuity, and insufficient detection capability for weak targets such as small drones and non-motorized vehicles.

[0006] 3. The antenna has high sidelobes and is easily affected by ground reflection, multipath interference and road clutter, resulting in low positioning and speed measurement accuracy. In roadside applications, it is prone to false detection and missed detection.

[0007] To address the aforementioned technical shortcomings, a multi-aperture high-gain antenna structure and detection enhancement method based on millimeter-wave radar are proposed. Without significantly increasing the transmit power, the antenna gain and receive sensitivity are greatly improved, the radar detection range is extended, the requirement for 500m roadside long-range detection is met, the detection probability of weak and long-range targets is increased, antenna sidelobes are effectively suppressed, and the anti-multipath interference and anti-clutter interference capabilities are enhanced. Summary of the Invention

[0008] The purpose of this invention is to solve the problems mentioned above by proposing a multi-aperture high-gain antenna structure and detection enhancement method based on millimeter-wave radar.

[0009] The objective of this invention can be achieved through the following technical solution: a multi-aperture high-gain antenna structure based on millimeter-wave radar, including a millimeter-wave radio frequency unit, a multi-aperture antenna array, a synchronous phase feed network, a beam control module, and a signal synthesis and processing unit;

[0010] The multi-aperture antenna array consists of at least two sets of sub-aperture antenna elements. Each set of sub-apertures is arranged in a preset spatial layout to form an equivalent large radiating aperture. The sub-aperture antenna elements include a near-field wide-beam transmitting antenna, a long-field narrow-beam transmitting antenna, and a receiving antenna.

[0011] The synchronous phase feed network connects the millimeter-wave radio frequency unit with each sub-aperture antenna unit, realizing synchronous excitation and phase calibration of each sub-aperture signal;

[0012] The beam control module is used to adjust the beam direction and suppress sidelobes.

[0013] The signal synthesis and processing unit is used to coherently superimpose and suppress noise from multiple received signals.

[0014] Furthermore, the millimeter-wave radio frequency unit provides the radio frequency signal source for the entire antenna structure.

[0015] Furthermore, the multi-aperture antenna array is the core radiating unit, which consists of at least two sets of sub-aperture antenna units. Each set of sub-apertures is arranged in a preset spatial layout to form an equivalent large radiating aperture.

[0016] Furthermore, the synchronous phase feed network consists of equal-length transmission lines, power dividers, and phase shifters. The feed structure uses CPW-Gound and adds shielded ground vias.

[0017] Furthermore, the beam control module adjusts the beam direction according to the detection scenario and distance, and achieves efficient suppression of antenna sidelobes, thus completing antenna sidelobe level suppression. At the same time, it supports flexible switching between close-range wide beams and long-range narrow beams, effectively suppressing ground reflections.

[0018] Furthermore, the multi-aperture antenna array is fabricated using an 8-layer board process. The top layer is a mixed-pressed RO3003 board (thickness 0.127mm, dielectric constant 3.0, loss tangent 0.0013). Layers 2, 4, and 7 are reference ground layers. The remaining dielectric boards are made of 370HR board. Each layer of board is stacked according to a preset thickness and dielectric constant.

[0019] The present invention also proposes a multi-aperture high-gain detection enhancement method based on millimeter-wave radar, comprising the following steps:

[0020] Step 1: Multi-aperture equivalent large-diameter component:

[0021] By pre-arranged spatial layout of multiple sub-apertures in a multi-aperture antenna array, an equivalent large radiation aperture is formed. The mode of wide beam of close-range 4X8 string feed array or narrow beam of long-range 6X12 string feed array can be flexibly switched according to actual detection needs. In-phase coherent superposition enhances power. Through the combination structure of equal-length transmission lines, power dividers and phase shifters in the synchronous phase feed network, the transmitted signals of each sub-aperture are phase-calibrated and amplitude-equalized.

[0022] Step 2: Beam Optimization and Interference Suppression

[0023] The direction of the radar beam is optimized by the beam control module, thereby suppressing the antenna sidelobe level.

[0024] Step 3: Coherent combining of received signals:

[0025] The signal synthesis and processing unit coherently superimposes the multiple target echo signals collected by the 2X12 string-fed array receiving antenna, while suppressing noise and interference signals.

[0026] Step 4: Low-power, high-precision detection:

[0027] Through the synergistic effect of the above steps, antenna gain can be improved without significantly increasing the transmission power.

[0028] Compared with traditional technologies, this invention addresses the core problems of traditional millimeter-wave radar antennas, such as low gain, short detection range, weak anti-interference capability, and low accuracy, through multi-aperture cooperative arraying, synchronous phase feeding, differentiated beam optimization, coherent signal synthesis, and dedicated substrate and feeding structure design. It offers the following significant advantages:

[0029] 1. Significantly improved antenna gain and detection range: Compared with traditional single-aperture antennas, the antenna gain of this invention is increased by more than 6dB, and the radar detection range is increased by more than 40%. In the 92GHz band, roadside applications can achieve stable detection at a distance of 500m, and the combined gain of the transmitting and receiving antennas at 500m is greater than 34dB, meeting the core requirements of long-distance roadside traffic monitoring.

[0030] 2. Significantly improved detection accuracy and probability: Through coherent signal synthesis and beam optimization, the receiving sensitivity and signal-to-noise ratio are greatly improved, and the detection probability of distant targets and weak targets with low radar cross-section (such as small drones and non-motorized vehicles) is significantly improved. In roadside applications, the ranging error is ≤0.1m, the speed measurement error is ≤±1km / h, and the angle resolution is significantly improved, realizing high-precision detection of vehicle speed, traffic flow and obstacles.

[0031] 3. Strong anti-interference capability and detection stability: The beam control module can suppress the sidelobe level to below -15dB, effectively suppressing ground reflection, multipath interference and environmental clutter, greatly reducing the probability of false detection and missed detection, and ensuring continuous and stable target tracking. It is suitable for harsh environments such as rain, fog and smoke, as well as complex roadside and security scenarios.

[0032] 4. Low power consumption, miniaturization, and easy integration: Long-distance, high-precision detection can be achieved without significantly increasing the transmission power, effectively reducing system power consumption, hardware costs, and heat dissipation pressure. The multi-aperture antenna array adopts an 8-layer board process design, with a compact structure. The feed network is compatible with conventional radar systems, making it easy to integrate and deploy in engineering.

[0033] 5. Differentiated beam design to adapt to multiple scenario requirements: Wide and narrow beam switching modes are designed for different detection needs at close and long distances. Wide beam at close distances reduces blind spots, while narrow beam at long distances is suitable for narrow-angle detection of lanes, taking into account the performance requirements of different detection scenarios.

[0034] 6. Multi-band compatibility and strong versatility: Supports multiple frequency bands such as 24GHz, 77GHz-79GHz, 80GHz, and 92GHz-94GHz, and can be widely used in various scenarios such as vehicle sensing, road traffic monitoring, security monitoring, drone detection and industrial high-precision detection. It is especially compatible with 77GHz band roadside millimeter-wave radar systems and has broad market prospects.

[0035] 7. Good phase consistency and low signal loss: The synchronous phase feeding network ensures that the phase difference of each sub-aperture is ≤±5°. It adopts the CPW-Gound feeding structure + shielded ground via and RO3003+370HR special board material design, which effectively reduces signal transmission loss and improves the radiation performance and working stability of the antenna. Attached Figure Description

[0036] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0037] Figure 1 This is a block diagram of the overall structure of the multi-aperture high-gain antenna device in this invention;

[0038] Figure 2 This is a schematic diagram of the layout of the multi-aperture antenna array in this invention;

[0039] Figure 3 This is a flowchart illustrating the millimeter-wave radar detection enhancement method of the present invention;

[0040] Figure 4 This is a comparative schematic diagram of the antenna in this invention;

[0041] Figure 5 This is a schematic diagram illustrating the radar detection range improvement effect of the present invention. Detailed Implementation

[0042] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0044] Please see Figures 1-5 As shown, the multi-aperture high-gain antenna structure based on millimeter-wave radar has a core structure including a millimeter-wave radio frequency unit, a multi-aperture antenna array, a synchronous phase feed network, a beam control module, and a signal synthesis and processing unit. The units work together to achieve high gain, low sidelobes, and long-range radar detection.

[0045] Millimeter-wave radio frequency unit: provides radio frequency signal source for the entire antenna structure, supports multi-band signal output of 24GHz, 77GHz-79GHz, 80GHz, and 92GHz-94GHz, preferably the 92GHz band to adapt to roadside millimeter-wave radar system, and realizes the initial processing of radio frequency signal transmission and reception.

[0046] Multi-aperture antenna array: The core radiating element consists of at least two sets of sub-aperture antenna elements. Each set of sub-apertures is arranged in a preset spatial layout to form an equivalent large radiating aperture, significantly improving the antenna's transmission gain. The sub-aperture antenna elements can be microstrip patch antennas, ridge waveguide antennas, Vivaldi antennas, or dielectric resonator antennas. To address the different needs of roadside detection at near and long ranges, the array integrates three dedicated sub-apertures: a near-range wide-beam transmitting antenna, a long-range narrow-beam transmitting antenna, and a receiving antenna.

[0047] Close-range wide-beam transmitting antenna: adopts a 4x8 string-fed array structure, with a gain of 19.1dB, an E-plane beamwidth of 17° and an H-plane beamwidth of 26°, effectively reducing the close-range detection blind zone;

[0048] Long-range narrow-beam transmitting antenna: adopts a 6X12 string-fed array structure, with a gain of 23.1dB, an E-plane beamwidth of 8.4° and an H-plane beamwidth of 13.7°, which is suitable for narrow-angle detection requirements of roadside long-distance lanes.

[0049] Receiving antenna: It adopts a 2X12 string-fed array structure with a gain of 18.7dB, an E-plane beamwidth of 7.3° and an H-plane beamwidth of 40°, which improves the coverage and sensitivity of the received signal. The arrangement of each sub-aperture ensures the effective synthesis of spatial gain. The combined gain of the transmitting and receiving antennas can be greater than 34dB at a detection distance of 500m.

[0050] Meanwhile, the multi-aperture antenna array is fabricated using an 8-layer board process. The top layer is made of RO3003 board material (thickness 0.127mm, dielectric constant 3.0, loss tangent 0.0013), layers 2, 4, and 7 are reference ground layers, and the remaining dielectric boards are made of 370HR board material. Each layer of board material is stacked according to the preset thickness and dielectric constant, which effectively reduces signal transmission loss and improves the structural stability and electromagnetic performance of the array.

[0051] Synchronous Phase Feed Network: Connecting the millimeter-wave RF unit to each sub-aperture antenna unit, the core of which is a combination of equal-length transmission lines, power dividers, and phase shifters. The core function of this network is to achieve synchronous excitation and phase calibration of the signals of each sub-aperture, ensuring that the amplitude of each sub-aperture signal is balanced and the phase difference is strictly controlled within ±5°. The feed structure uses CPW-Gound and adds shielded ground vias (W=0.32mm, Gap=0.254mm) to further improve phase consistency and reduce signal loss of the feed network.

[0052] Beam control module: Used to adjust the beam direction according to the detection scene and distance, and to achieve efficient suppression of antenna sidelobes. It can suppress antenna sidelobe levels to below -15dB, while supporting flexible switching between close-range wide beam and long-range narrow beam. It effectively suppresses ground reflection, multipath reflection, and environmental clutter interference, improving the anti-interference capability of the detection. A comparison diagram of the radiation pattern of this antenna structure with that of a traditional antenna is shown below. Figure 4 As shown, the sidelobe suppression effect and main lobe gain of the present invention are significantly better than those of traditional antennas.

[0053] Signal synthesis and processing unit: performs coherent superposition and noise suppression on the multiple received signals from the receiving antennas in the multi-aperture antenna array, amplifies the effective target echo signal, reduces the influence of environmental noise and interference signals, significantly improves receiving sensitivity and signal-to-noise ratio, and realizes effective detection of weak targets and long-distance targets.

[0054] It supports one or more operating frequency bands from 24GHz, 77GHz-79GHz, 80GHz, and 92GHz-94GHz. It has a compact structure and is easy to integrate. It can be directly adapted to various millimeter-wave radar systems such as vehicle-mounted, roadside, security, and industrial systems without requiring major modifications to the existing hardware architecture.

[0055] This invention also proposes a detection enhancement method based on a multi-aperture high-gain antenna structure for millimeter-wave radar. This method utilizes a full-process technical approach involving multi-aperture coordination, phase coherence, beam optimization, and signal synthesis to achieve a comprehensive improvement in detection performance without significantly increasing transmission power. Specifically, it includes the following steps:

[0056] Multi-aperture equivalent large-aperture component: By pre-arranging multiple sub-apertures (near-range wide-beam transmitting antenna, far-range narrow-beam transmitting antenna, and receiving antenna) of the multi-aperture antenna array, an equivalent large radiating aperture is formed. The antenna can be flexibly switched between the near-range 4X8 string feed array wide-beam mode and the far-range 6X12 string feed array narrow-beam mode according to actual detection needs, thereby improving the transmission gain of the antenna from the hardware structure.

[0057] In-phase coherent superposition power enhancement: Through the combination structure of equal-length transmission lines, power dividers and phase shifters in the synchronous phase feed network, the phase calibration and amplitude equalization of the transmitted signals of each sub-aperture are performed to ensure that the phase difference is controlled within ±5°, thereby realizing the in-phase coherent superposition of the transmitted signals of each sub-aperture, which greatly improves the far-field radiation power density and enhances the signal strength of long-distance detection.

[0058] Beam optimization and interference suppression: The beam control module optimizes the direction of the radar beam, suppressing the antenna sidelobe level to below -15dB, effectively suppressing ground reflection, multipath reflection, and environmental clutter interference in road, security, and industrial scenarios, reducing the probability of false detection and missed detection, and improving the stability of detection.

[0059] Coherent signal synthesis: The signal synthesis processing unit coherently superimposes the multiple target echo signals collected by the 2X12 string-fed array receiving antenna, while suppressing noise and interference signals, amplifying the effective signal, improving the receiving sensitivity and signal-to-noise ratio, and realizing the effective detection of weak targets with low radar cross-section and long-range targets.

[0060] Low-power, high-precision detection is achieved through the synergistic effect of the above steps. Without significantly increasing the transmission power, the antenna gain is increased by more than 6dB, the radar detection range is increased by more than 40%, and the sum of the gains of the transmitting and receiving antennas is greater than 34dB at a detection range of 500m. At the same time, the accuracy of target detection, ranging accuracy (ranging error ≤0.1m), angle resolution and velocity accuracy (velocity error ≤±1km / h) are greatly improved, enabling continuous and stable tracking of targets.

[0061] For example: a multi-aperture high-gain antenna structure suitable for vehicle-mounted 77GHz-79GHz;

[0062] This embodiment is applicable to vehicle-mounted 77GHz-79GHz millimeter-wave radar systems. It uses three sets of sub-aperture antenna elements to form a multi-aperture array, including one 4x8 string-fed array close-range wide-beam transmitting antenna, one 6x12 string-fed array long-range narrow-beam transmitting antenna, and one 2x12 string-fed array receiving antenna. Equal amplitude and equal phase excitation are achieved through a synchronous phase feeding network, and the beam control module suppresses sidelobes to below -18dB.

[0063] Applied to vehicle-mounted sensing scenarios, compared with traditional vehicle-mounted 77GHz radar antennas, the antenna structure gain is improved by 6-12dB, the detection range is increased by more than 40%, and the ranging error is ≤0.1m. It can achieve long-distance, high-precision detection of vehicles, pedestrians, and non-motorized vehicles in front, with excellent sidelobe suppression effect, effectively resisting road clutter and multipath interference, and improving the perception safety of intelligent driving.

[0064] Example 2: A 92GHz multi-aperture high-gain antenna structure suitable for long-distance roadside traffic monitoring;

[0065] This embodiment is dedicated to the 92GHz frequency band and is suitable for long-range roadside millimeter-wave radar systems. It adopts a three-sub-aperture layout, including two sets of 6x12 string-fed array long-range narrow-beam transmitting antennas and one set of 2x12 string-fed array receiving antennas. Through beam optimization and phase coordination control, it effectively reduces the impact of road multipath interference and environmental clutter.

[0066] In roadside applications, the combined gain of the transmitting and receiving antennas is greater than 34dB at a detection distance of 500m, the speed measurement error is ≤±1km / h, and the ranging error is ≤0.1m. It can achieve 24-hour high-precision detection of vehicle speed, traffic flow, vehicle type and obstacles on the road. It is resistant to rain, fog and dust interference in all weather conditions, and the target tracking is continuous and stable. It is suitable for roadside traffic monitoring on highways and urban main roads.

[0067] Example 3: A 24GHz multi-aperture high-gain antenna structure suitable for security and drone detection;

[0068] This embodiment is applicable to a 24GHz millimeter-wave radar system and adopts a four-aperture planar array structure, including two sets of 4x8 string-fed wide-beam transmitting antennas and two sets of 2x12 string-fed receiving antennas. After coherent combining of the received signals, the signal-to-noise ratio is greatly improved.

[0069] It is applied to security monitoring and drone detection scenarios, increasing the detection range of small drones and other targets with low radar cross-sections by more than 50%. It has strong anti-clutter capabilities and can achieve long-range early warning, precise positioning and continuous tracking of intrusion targets. It is suitable for security scenarios such as parks, airports and borders.

[0070] Example 4: A 60GHz multi-aperture high-gain antenna structure suitable for high-precision industrial testing;

[0071] This embodiment is applicable to a 60GHz millimeter-wave radar system and adopts a dual-aperture high-gain structure, including a 6x12 string-fed array narrow beam transmitting antenna and a 2x12 string-fed array receiving antenna. It features a narrow beam, strong directivity, and high phase consistency.

[0072] It is applied to high-precision industrial inspection scenarios, achieving millimeter-level ranging accuracy. It is suitable for industrial ranging, liquid level detection, material positioning, equipment gap detection and other industrial scenarios. It has a compact structure and can be integrated into industrial robots and inspection equipment. It has strong resistance to industrial environmental noise interference.

[0073] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A multi-aperture high-gain antenna structure based on millimeter-wave radar, characterized in that, It includes a millimeter-wave radio frequency unit, a multi-aperture antenna array, a synchronous phase feed network, a beam control module, and a signal synthesis and processing unit; The multi-aperture antenna array consists of at least two sets of sub-aperture antenna elements. Each set of sub-apertures is arranged in a preset spatial layout to form an equivalent large radiating aperture. The sub-aperture antenna elements include a near-field wide-beam transmitting antenna, a long-field narrow-beam transmitting antenna, and a receiving antenna. The synchronous phase feed network connects the millimeter-wave radio frequency unit with each sub-aperture antenna unit, realizing synchronous excitation and phase calibration of each sub-aperture signal; The beam control module is used to adjust the beam direction and suppress sidelobes. The signal synthesis and processing unit is used to coherently superimpose and suppress noise from multiple received signals.

2. The multi-aperture high-gain antenna structure based on millimeter-wave radar according to claim 1, characterized in that, The millimeter-wave radio frequency unit provides the radio frequency signal source for the entire antenna structure.

3. The multi-aperture high-gain antenna structure based on millimeter-wave radar according to claim 1, characterized in that, The multi-aperture antenna array is the core radiating unit, which consists of at least two sets of sub-aperture antenna units. Each set of sub-apertures is arranged in a preset spatial layout to form an equivalent large radiating aperture.

4. The multi-aperture high-gain antenna structure based on millimeter-wave radar according to claim 1, characterized in that, The synchronous phase feed network consists of equal-length transmission lines, power dividers, and phase shifters. The feed structure uses CPW-Gound and adds shielded ground vias.

5. The multi-aperture high-gain antenna structure based on millimeter-wave radar according to claim 1, characterized in that, The beam control module adjusts the beam direction according to the detection scenario and distance, and achieves efficient suppression of antenna sidelobes, thus completing antenna sidelobe level suppression. It also supports flexible switching between close-range wide beams and long-range narrow beams, effectively suppressing ground reflections.

6. The multi-aperture high-gain antenna structure based on millimeter-wave radar according to claim 1, characterized in that, The multi-aperture antenna array is fabricated using an 8-layer board process. The top layer is made of RO3003 mixed-pressed board material, layers 2, 4, and 7 are reference ground layers, and the remaining dielectric boards are made of 370HR board material. The boards are stacked according to the preset thickness and dielectric constant.

7. A detection enhancement method based on a multi-aperture high-gain antenna structure for millimeter-wave radar, employing the multi-aperture high-gain antenna structure based on millimeter-wave radar as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Multi-aperture equivalent large-diameter component: By pre-arranged spatial layout of multiple sub-apertures in a multi-aperture antenna array, an equivalent large radiation aperture is formed. The mode of wide beam of close-range 4X8 string feed array or narrow beam of long-range 6X12 string feed array can be flexibly switched according to actual detection needs. In-phase coherent superposition increases power. Through the combination structure of equal-length transmission lines, power dividers and phase shifters in the synchronous phase feed network, the transmitted signals of each sub-aperture are phase-calibrated and amplitude-equalized. Step 2: Beam Optimization and Interference Suppression The direction of the radar beam is optimized by the beam control module, thereby suppressing the antenna sidelobe level. Step 3: Coherent combining of received signals: The signal synthesis and processing unit coherently superimposes the multiple target echo signals collected by the 2X12 string-fed array receiving antenna, while suppressing noise and interference signals. Step 4: Low-power, high-precision detection: Through the synergistic effect of the above steps, antenna gain can be improved without significantly increasing the transmission power.

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