S-band waveguide slot digital phased array antenna and digital array radar including the same

Abstract

The present invention discloses an S-band waveguide crack digital phased array antenna array and a digital array radar including the same, belonging to the field of antenna microwave technology. The present invention includes a waveguide, a coupler, a filter, a TR component, a digital component, a frequency source module, a lightning control module and a DBF module, etc.; the waveguide forms an antenna array to form a traveling wave array; the lightning control module sends a timing control signal to each digital component of the array according to the instruction; when the array is transmitting, the frequency source module outputs the local oscillator signal of the frequency modulation signal, which is mixed and amplified to the radio frequency transmission channel by the digital component, and the TR component is stimulated to perform saturation amplification and filtering, and radiates outward through the waveguide to form a transmission beam; when the array is receiving, the echo signal enters the TR component from the waveguide, reaches the digital component after limiting and amplification, and is processed by DBF to form an adaptive multi-beam. The present invention adopts a digital solution for both transmission and reception, with a compact structure, a high degree of digitization, good reliability, and reduced insertion loss between transmission networks.

Description

Technical Field

[0001] The present invention belongs to the field of antenna microwave technology, and in particular relates to an S-band waveguide slot digital phased array antenna array and a digital array radar comprising the same. Background Art

[0002] Analog phased array antennas generally use phase shifters to achieve phase shifting of antenna units in the array, and all beam synthesis is completed on the array. Existing S-band analog arrays form fewer beams and require multiple power splitter networks, resulting in reduced signal-to-noise ratio, reduced power coverage, and greater insertion loss between transmission networks.

[0003] The current radar field is in the stage of upgrading from analog phased array radar to digital phased array radar. The technical iteration of phased array radar can be divided into three stages: passive phased array, active phased array, and digital array phased array. Digital array has promoted the advancement of active phased array radar technology, which in turn promoted the proposal and development of digital array radar. Overall, phased array radar is constantly updating and iterating towards higher efficiency, smaller size, higher reliability, and greater flexibility.

[0004] Compared with analog phased array radar, digital phased array radar has outstanding advantages in anti-interference ability, detection accuracy, functional diversity, etc. Its low power consumption, high stability and high precision also make it one of the important directions of phased array radar development. As the analog-to-digital conversion (ADC) technology of digital array continues to mature, the sampling frequency is getting higher and higher, further improving the digitization and integration of radar systems.

[0005] Digital antenna arrays are generally composed of antenna arrays, radomes, high-frequency boxes, and structural frames. The high-frequency box contains active transceiver channels, array power supplies, and integrated networks. Digital antenna arrays have compact structures, high digitization, and good reliability. They can solve the problems caused by analog arrays, reduce insertion loss between transmission networks, and improve the power of radars. In the future, with the further development of high-speed digital signal processing technology, digital phased array radars are gradually penetrating various application fields, laying a solid foundation for the application of phased array radars in multiple bands.

[0006] In view of the above development trends, how to use digital control to achieve waveform generation, phase shifting, amplitude control and analog-to-digital conversion, eliminate multiple sets of networks used for phase shifting and attenuation in analog arrays, further simplify the microwave RF front end of the antenna array, realize spatial power synthesis, and enable the S-band digital phased array to have more flexible beam synthesis performance has become a problem that needs to be solved. Summary of the invention

[0007] The purpose of the present invention is to provide an S-band waveguide slot digital phased array antenna array and a digital array radar including the same, which adopts digital solutions for both transmission and reception, and has a compact structure, a high degree of digitization, and good reliability, thereby reducing the insertion loss between transmission networks, improving the power of the radar, and being able to well solve the problems caused by analog arrays.

[0008] Specifically, on the one hand, the present invention provides an S-band waveguide crack digital phased array antenna array, including a waveguide, a coupler, a filter, a TR component, a digital component, a frequency source plug-in box, a local oscillator network, a clock network, and an optical fiber network; the frequency source plug-in box is provided with a frequency source module, a lightning control module, and a DBF module;

[0009] A plurality of the waveguides form an antenna array, and slots with opposite inclination angles are sequentially arranged at set intervals on the narrow side of the waveguide to form a traveling wave array, and the set interval is not equal to half the wavelength of the waveguide; the polarization form of the waveguide is horizontal polarization, and is divided into two types of waveguides, type A and type B, and the slots arranged on the two types of waveguides are the same, and the type A and type B waveguides are arranged adjacently and staggered on the antenna array plane;

[0010] The filter is arranged between the coupler and the TR component to filter the received and transmitted signals;

[0011] Each of the TR components includes a transmitting module, a plurality of RF transmitting channels, a receiving module and a plurality of RF receiving channels, and a plurality of TR components correspond to a digital component;

[0012] The digital component includes several radio frequency interfaces, two of which are clock and local oscillator interfaces, and the rest are radio frequency receiving channel interfaces and radio frequency transmitting channel interfaces;

[0013] The TR component and the digital component are connected via a radio frequency cable to achieve the transmission and reception conversion of the array surface;

[0014] The mine control module converts the external working instructions into a timing control signal, and sends the timing control signal to each digital component of the array through the optical fiber network; when the array transmits, the timing control signal controls the frequency source module to output a pulse wave local oscillator signal of a single carrier frequency, a linear frequency modulation signal or a nonlinear frequency modulation signal of a certain frequency point, which is mixed and amplified by the digital component to the RF transmission channel, and stimulates the transmission module of the TR component to perform saturation amplification and filtering, and finally radiates to the external space through the waveguide line feed to form a transmission beam; when the array receives, the target reflection echo signal received by the antenna enters the receiving module of the TR component through the waveguide line feed, and after passive limiting and LNA low-noise amplification, reaches the digital component, and then undergoes mixing, intermediate frequency sampling, A / D conversion and DDC down-conversion, and the output digital signal is sent to the DBF module for processing to achieve digital phase matching and form an adaptive multi-beam;

[0015] The local oscillator network provides a local oscillator signal for each digital component;

[0016] The clock network provides a clock signal to each digital component;

[0017] The optical fiber network amplifies the timing control signal and distributes it to each digital component, frequency source module and DBF module, and converts the digital signal output by the digital component into an optical signal and transmits it to the DBF module.

[0018] Furthermore, when the array is transmitting, the timing control signal controls the frequency source module to output a pulse wave local oscillator signal of a single carrier frequency, a linear frequency modulation signal or a nonlinear frequency modulation signal at a certain frequency point, which is mixed and amplified to the RF transmission channel by the digital component, and the transmitting module of the TR component is stimulated to perform saturation amplification and filtering, and finally radiated to the external space through the waveguide line to form a transmission beam, including:

[0019] The clock signal and local oscillator signal from the array are input to each digital component through the power division network. At the same time, the DDS in the RF transmission channel of each digital component generates an intermediate frequency signal of a certain frequency point according to the requirements of the received timing control signal. After mixing with the local oscillator signal on the mixer, it is filtered by a bandpass filter to generate the RF excitation signal required for power amplification and sent to each RF transmission channel of each TR component; and through switch control, the RF excitation signal enters the transmission module for power amplification, and the amplified power signal is output through the circulator, and finally transmitted to the waveguide slot antenna by the transmission feeder, and radiated to the external space; each transmission channel of the array performs power synthesis in space, and the transmission phase of each transmission channel weighted by the shaping weighting coefficient is controlled by DDS to form a corresponding shaped beam.

[0020] Furthermore, when the array receives, the target reflected echo signal received by the antenna enters the receiving module of the TR component through the waveguide line feed, reaches the digital component after passive limiting and LNA low-noise amplification, and then goes through mixing, intermediate frequency sampling, A / D conversion and DDC down-conversion, and the output digital signal is sent to the DBF module for processing to realize digital phase matching and form an adaptive multi-beam, including:

[0021] When the array receives, the target reflected echo signal received by the antenna enters the TR component, first passes through the circulator of the TR component, and the timing signal controls the T / R switch to switch to the receiving channel, and then passes through limiting and low-noise amplification in sequence, and enters the RF receiving channel of the digital component. After being mixed with the local oscillator signal transmitted by the frequency source module in the mixer, it is filtered by a bandpass filter to generate an intermediate frequency signal of a certain frequency point; the intermediate frequency signal is output as high-speed optical fiber data after A / D sampling and digital orthogonal down-conversion, and is transmitted to the DBF module through the optical fiber network for multi-beam synthesis.

[0022] Furthermore, the S-band waveguide crack digital phased array antenna array also includes a monitoring component, which is used for channel amplitude and phase calibration in the array monitoring mode, as well as troubleshooting of antenna feed lines and components;

[0023] The local oscillator network provides a local oscillator signal for each monitoring component; the clock network provides a clock signal for each monitoring component; the optical fiber network amplifies the timing control signal and distributes it to each monitoring component;

[0024] The channel amplitude and phase calibration in the array monitoring mode includes:

[0025] During the internal monitoring of transmission, the monitored transmission channel of the antenna array couples a part of the signal through the coupler and sends it to the monitoring component through the monitoring network. The I and Q data output by the monitoring component are sent to the DBF through the optical fiber network. The DBF transmits it to the external display and control computer through the optoelectronic network switch, and compares it with the standard monitoring amplitude and phase values ​​to complete the calculation and calibration of the array amplitude and phase data.

[0026] During external monitoring of the transmission, the signal radiated by the measured transmission channel is received by the external monitoring antenna and sent to the monitoring component. The monitoring component outputs I and Q data to the DBF, and then to the display and control computer to complete the phase correction.

[0027] During internal monitoring, the monitoring component outputs RF monitoring signals, which are sent to each coupler through the monitoring network and enter the array receiving channel through the coupler. The receiving channel outputs I and Q data to DBF, and the display and control computer simultaneously completes the recording and calculation of the amplitude and phase calibration data of each array receiving channel, and compares them with the standard internal monitoring data.

[0028] When receiving external monitoring, the monitoring component outputs a radio frequency monitoring signal, which is radiated to the array surface through the external monitoring antenna. After the line feed receives the signal, it is amplified, filtered and down-converted through the receiving channel and converted into a digital signal. After DBF receives it, it is sent to the display and control computer to complete the calculation of the correction value.

[0029] Furthermore, the S-band waveguide crack digital phased array antenna array also includes a detection component, which detects external radiation environment signals in the airspace near the normal line of the main antenna and within the working frequency band;

[0030] The clock network provides a clock signal for each detection and receiving component;

[0031] The optical fiber network amplifies the timing control signal and distributes it to each detection and receiving component.

[0032] Furthermore, during phase scanning, the pitch phase difference within the array is The value is calculated as:

[0033]

[0034] in, is the free space wavelength at the corresponding frequency, is the spacing between waveguides, is the pitch scanning angle, is the pitch angle of the array, φ is the frequency sweep angle in azimuth that deviates from the array normal, and the calculation formula is:

[0035]

[0036] in, is the spacing between the slots of a single waveguide, is the free space wavelength at the corresponding frequency, is the length of the inner wall of the wide side of the waveguide.

[0037] On the other hand, the present invention also provides a digital array radar, characterized in that it includes the above-mentioned S-band waveguide slot digital phased array antenna array surface.

[0038] The beneficial effects of the S-band waveguide slot digital phased array antenna array and the digital array radar including the same of the present invention are as follows:

[0039] The S-band waveguide slot digital phased array antenna array and the digital array radar including the same of the present invention adopt digital schemes for both transmission and reception, realize digitalization of signal form and beam forming, and have relatively large comprehensive advantages over analog arrays.

[0040] The S-band waveguide slot digital phased array antenna array and the digital array radar including the same of the present invention no longer have traditional phase shifters, and the phase difference of the transmitted signal is directly generated by direct digital frequency synthesis (DDS) technology, and power synthesis is performed in space, which simplifies control and reduces power consumption of the array.

[0041] The receiving beam is matched by digital beam forming (DBF) technology to form adaptive multi-beams. The receiving beam on the azimuth plane of the antenna is formed by the waveguide slot antenna, which is a fixed sum beam relative to the array surface. The antenna realizes full digital beamforming for transmission and reception in the elevation plane. The receiving beam on the elevation plane is formed by DBF through digital components, which can realize multiple beams at the same time, eliminating the multiple sets of column feeds required for analog beams. Correspondingly, the efficiency of the antenna array surface is greatly improved, thereby improving the signal-to-noise ratio of the radar receiving signal.

[0042] The S-band waveguide crack digital phased array antenna array and the digital array radar including the same of the present invention have a compact structure, a high degree of digitization and good reliability. Specifically:

[0043] In the S-band waveguide slot digital phased array antenna array surface and the digital array radar including the same of the present invention, the analog TR component and the digital component are independent of each other.

[0044] The digital components adopt a multi-channel design with high integration, good inheritance and interchangeability.

[0045] Except for the optical fiber interface, TR components, digital components and transceiver power supplies are all blindly plugged and interconnected through the blind plug interface of the integrated backplane, which is convenient for assembly, testing and maintenance.

[0046] The control of digital components and frequency source modules all adopts optical signals, which ensures the reliability of control signals.

[0047] The transceiver and power components that generate more heat are cooled through external liquid cooling units and liquid cooling pipes laid inside the array, which has higher reliability than air cooling. The frequency source plug-in box is cooled by air conditioning air, focusing on ensuring the stability of the single-point frequency source plug-in box on the array.

[0048] The high-frequency box has a compact layout, with TR components and digital components arranged alternately up and down. The transceiver power supply, frequency source plug-in box, etc. are located at the bottom of the high-frequency box, which makes the relatively narrow high-frequency box reasonably arranged.

[0049] The array surface has internal and external monitoring functions, which can perform complete health management of the antenna array surface.

[0050] The S-band waveguide crack digital phased array antenna array and the digital array radar including the same of the present invention reduce the insertion loss between transmission networks, improve the power of the radar, and can well solve the problems caused by the analog array. Specifically, improvements are made in the following two aspects, so that the link between the TR component and the antenna has a relatively low insertion loss, which can enhance the power of the radar.

[0051] First, the ultra-low sidelobe waveguide slot antenna technology is adopted. The antenna radiation form adopts waveguide slot technology, which significantly improves the efficiency of radiation line feed, and the gain is about 1.5dB higher than that of air microstrip radiation line feed.

[0052] Secondly, the digital transceiver component technology is used to transfer the traditional pre-transmitter stage and high-frequency receiver from outside the array to each TR component for digital transmission and control, eliminating the microwave power division network between the TR component and the receiver and pre-transmitter stage, reducing the resulting link insertion loss by nearly 3dB; in addition, the digital array does not lose the signal-to-noise ratio during the transmission of the received signal, and can use software to arbitrarily change the beam synthesis method in the digital domain, which also reduces the transmission power of a single channel to improve the reliability of the array. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of the antenna array layout of an embodiment of the present invention.

[0054] Figure 2Schematic diagram of a transmission link according to an embodiment of the present invention.

[0055] Figure 3 4 is a schematic diagram of a receiving link according to an embodiment of the present invention.

[0056] Figure 4 Schematic diagram of a waveguide array according to an embodiment of the present invention.

[0057] Figure 5 Schematic diagram of transmit beamforming according to an embodiment of the present invention.

[0058] Figure 6 It is a schematic diagram of receiving multi-beams according to an embodiment of the present invention.

[0059] Figure 7 Schematic diagram of a waveguide crack frequency sweep angle curve according to an embodiment of the present invention. DETAILED DESCRIPTION

[0060] The present invention is further described in detail below in conjunction with embodiments and with reference to the accompanying drawings.

[0061] Embodiment 1:

[0062] One embodiment of the present invention is an S-band waveguide slot digital phased array antenna array, such as Figure 1 The specific technical solution is given below:

[0063] 1. Antenna Array Layout

[0064] The function of the antenna array is to transmit pulse electromagnetic signals in a certain signal form and power, and to receive weak electromagnetic signals reflected by the target and amplify, filter, and AD convert them, and transmit them to the back-end signal detection equipment. The S-band waveguide crack digital phased array antenna array of the present invention, when transmitting, the antenna array amplifies, filters, radiates, and synthesizes spatial power of the transmitted signal, and uses DDS technology to scan the transmission beam according to the working instructions, and radiates energy in different predetermined spatial directions. When receiving, the antenna array amplifies, filters, AD converts, and down-converts the target echo, and hands it over to the DBF module for processing to form a digital multi-beam.

[0065] The antenna array of the present invention mainly includes waveguide, coupler, filter, TR component, digital component, frequency source plug-in box, local oscillator network, clock network, optical fiber network and other equipment. The frequency source plug-in box is provided with frequency source module, lightning control module and DBF module.

[0066] like Figure 1As shown in the figure, the high-frequency box of the array is divided into four relatively independent boxes, each with a door. TR components and digital components are arranged alternately in the two high-frequency boxes on the right, and power components, frequency source plug-in boxes, fan coil units and other equipment are placed in the two boxes on the left. The frequency source plug-in box is located at the bottom of the high-frequency box on the upper left, and the power component is located in the high-frequency box on the lower left, which is convenient for operation and maintenance, so that the relatively small high-frequency box space of the array is reasonably arranged.

[0067] The waveguide is the antenna radiation unit, one end of which is connected to the waveguide coaxial converter as the signal input end, and the other end is connected to the load to absorb the remaining power. The waveguide is connected to one side of the high-frequency box through a low-loss, high-power-resistant cable at the feed end, where it is transferred to the high-frequency box by a section of threaded tube cable with a smaller diameter. After passing through the high-frequency box, the cable is connected to the coupler, and then connected to the TR component through the backplane by another section of cable. The coupler is used for array monitoring. Preferably, if Figure 2 As shown, the antenna array is composed of a number of (for example, 32) standard aluminum waveguides, and slots with opposite inclination angles are arranged in sequence at set intervals on the narrow side of the waveguide to form a traveling wave array, and the set interval is not equal to the half waveguide wavelength. The polarization form of the waveguide is horizontal polarization, which is divided into two types of waveguides, type A and type B. The slots set on the two types of waveguides are the same. The type A and type B waveguides are arranged adjacently and staggered on the antenna array surface to suppress the cross-polarization level. When the waveguide is excited, the current is parallel to the narrow side direction, and the current is cut by the slot, so that the slot can resonate at the set frequency. Since the phase difference of each slot in the waveguide is fixed and the azimuth direction is passive, the antenna array presents a relatively fixed sum beam in the azimuth direction. Active components are connected to each waveguide on the pitch plane, and the phase can be adjusted at any time. DBF processes the I and Q data output by the digital component in parallel to form multiple receiving beams.

[0068] The filter is arranged between the coupler and the TR component to filter the received and transmitted signals, thereby achieving the purpose of using one filter for antenna transmission and reception.

[0069] The digital components in the high-frequency box contain several RF interfaces, two of which are clock and local oscillator interfaces, which are used to receive clock signals and local oscillator signals respectively, and the rest are RF receiving channel interfaces and RF transmitting channel interfaces, which are used to connect to the RF receiving channel interface and RF transmitting channel interface of the TR component respectively. For example, the back of the digital component in the high-frequency box contains 10 RF interfaces, two of which are clock signal interfaces and local oscillator signal interfaces, and the remaining 8 are RF transceiver channel interfaces.

[0070] TR components and digital components are connected through RF cables behind the integrated backplane to achieve the array's transceiver conversion. For example, the back of each TR component includes several (for example, two) transmission channels and several (for example, two) receiving channel interfaces. Several (for example, four) TR components correspond to one digital component. TR components and digital components are blindly connected through the interface on the backplane. The number of TR components is determined by the number of channels of the digital component, the array channel scale, and the number of TR component channels. For example, the array contains 32 waveguides, that is, 32 active channels, the digital component adopts an 8-channel design, and the TR component adopts a 2-channel design. At this time, the array requires 16 TR components and 4 digital components.

[0071] Preferably, the S-band waveguide crack digital phased array antenna array of the present invention further includes a monitoring component for channel amplitude and phase calibration in the array monitoring mode, and troubleshooting of antenna feed lines and components. The S-band waveguide crack digital phased array antenna array of the present invention further includes a detection component for detecting external radiation environment signals in the airspace near the main antenna normal and in the working frequency band.

[0072] The frequency source plug-in box is provided with a lightning control module, which converts the working instructions issued by the external display and control computer into a timing control signal, and sends the timing control signal to each digital component of the array through the optical fiber network.

[0073] The local oscillator network provides local oscillator signals for each digital component and monitoring component; the clock network provides clock signals for each digital component, monitoring component and detection component, and the monitoring network implements health management for the array. The local oscillator network, clock network and monitoring network are distributed at the bottom or side of the two high-frequency boxes on the right to save wiring space.

[0074] Preferably, the power supply components in the S-band waveguide slot digital phased array antenna array of the present invention are blindly connected to the power distribution network behind the integrated backplane to provide stable voltage support for the equipment in the array, and the power supply monitoring and aggregation equipment monitors the voltage and current of each power supply in the array in real time.

[0075] Preferably, a fan coil unit is used in the S-band waveguide slot digital phased array antenna array surface of the present invention to provide heat dissipation for the frequency source plug-in box alone to ensure its stability and reliability.

[0076] 2. Transmit Link

[0077] When the array is transmitting, it can control the transmission of a single channel or the entire array. First, the timing control signal is sent through the mine control module. The timing control signal controls the frequency source module to output a pulse wave local oscillator signal of a single carrier frequency, linear frequency modulation signal or nonlinear frequency modulation signal at a certain frequency point, which is then mixed and amplified by the digital component and sent to the RF transmission channel of the TR component, stimulating the transmission module of the TR component to perform saturation amplification and filtering, and finally radiated to the external space through waveguide feeding to form a transmission beam.

[0078] For example, Figure 3 As shown, the clock signal and local oscillator signal from the array are input to each digital component through the power division network. At the same time, the DDS in the RF transmission channel of each digital component generates an intermediate frequency signal of a certain frequency point according to the requirements of the received timing control signal. After mixing with the local oscillator signal on the mixer, it is filtered through a bandpass filter to generate the RF excitation signal required for amplification and sent to each RF transmission channel of each TR component. The RF excitation signal is then switched to the transmission module for power amplification through switching. The amplified power signal is then output through the circulator and finally transmitted to the waveguide slot antenna by the transmission feeder to radiate to the external space. Each (for example, 32) transmission channel of the array performs power synthesis in space, and the transmission phase of each transmission channel weighted by the shaping weighting coefficient is controlled by DDS to form a corresponding shaped beam. The synthesized beam is shown in Figure 4 As shown, there are three shapes: cosecant, widened, and pencil-shaped.

[0079] 3. Receiving Link

[0080] When the array receives, the target reflected echo signal is received by the antenna unit, fed into the receiving module of the TR component by the waveguide, and reaches the digital component after passive limiting and LNA (low noise amplifier) ​​low noise amplification. After mixing, intermediate frequency sampling, A / D conversion and DDC down conversion, the output digital signal is sent to the DBF module for processing to realize digital matching and form adaptive multi-beam.

[0081] For example, Figure 5 As shown, the weak target reflected echo signal received from the waveguide crack antenna unit enters the TR component through the waveguide line feed, first passes through the circulator of the TR component, and the timing signal sent by the mine control module controls the T / R switch to switch to the receiving channel, and then passes through limiting and low-noise amplification in sequence, and enters the RF receiving channel of the digital component. After being mixed with the local oscillator signal transmitted from the antenna array frequency source module in the mixer, it is filtered by a bandpass filter to generate an intermediate frequency signal of a certain frequency point. The intermediate frequency signal is output as I and Q digital signals after A / D sampling and digital orthogonal down conversion (DDC), and is transmitted to DBF through the optical fiber network for multi-beam synthesis. DBF can form 20 beams in narrowband, as shown in Figure 6 shown.

[0082] Preferably, in another embodiment, in order to improve the accuracy of radar in height measurement, the S-band waveguide slot digital phased array antenna array of the present invention, when performing main beam synthesis, the pitch phase difference within the array plane is The calculation of the value takes into account the variable of the frequency sweep angle that deviates from the array normal in azimuth. The details are as follows:

[0083] The antenna beam pointing direction of the S-band waveguide crack digital phased array antenna of the present invention deviates from the waveguide array normal line by a certain angle in the azimuth direction, and has a frequency scanning characteristic within a certain angle as the operating frequency changes. The frequency scanning angle curve of the azimuth direction of the waveguide crack deviating from the array normal line is as follows: Figure 7 As shown, the formula for the corresponding frequency sweep angle φ in azimuth direction that deviates from the array normal is as follows:

[0084]

[0085] in, is the spacing between the slots of a single waveguide (in mm), is the free space wavelength at the corresponding frequency (in mm), is the length of the inner wall of the waveguide wide side (in mm).

[0086] In the actual use of the S-band waveguide slot digital phased array antenna array of the present invention, the antenna array surface will have a certain inclination angle in the elevation direction, so during phase scanning, the elevation phase difference within the array surface is The calculation of the value requires the addition of the variable of the array inclination angle and the pitch phase difference within the array. The value is calculated as follows:

[0087]

[0088] in, is the wavelength of the corresponding frequency (in mm), is the spacing between the waveguides (in mm), is the pitch scanning angle, It is the pitch angle of the array.

[0089] However, since the azimuth beam of the S-band waveguide slot digital phased array antenna deviates from the normal direction of the waveguide array and changes with the frequency, the radar has errors in height measurement accuracy. Therefore, it is necessary to adjust the elevation phase difference within the array. The variable of frequency sweep angle φ, which deviates from the array normal in azimuth, is added to the calculation formula of the value, and the final elevation phase difference within the array plane is The value is calculated as

[0090]

[0092] 4. Clock Network

[0093] The clock network distributes the clock signal output by the frequency source module to each digital component and ensures that the clock signal strength is large enough. When the S-band waveguide crack digital phased array antenna array includes monitoring components and detection components, the clock network also distributes the clock signal output by the frequency source module to each monitoring component and detection component and ensures that the clock signal strength is large enough.

[0094] For example, the frequency source module outputs a sine wave reference clock signal of a certain frequency point, and distributes the clock signal to each digital component, detection component, and monitoring component through a power divider. Figure 2 The antenna array shown contains 32 waveguides, i.e. 32 RF front-end channels, and the digital component is designed in the form of 8 channels. Therefore, the frequency source module distributes the clock signal to 4 digital components, 1 detection component, and 1 monitoring component through a one-to-six power divider, and the clock signal strength reaching the component is 2dBm.

[0095] 5. Local Oscillator Network

[0096] The frequency source module outputs two local oscillator signals, one for the digital component and the other for the monitoring component, so as to separate the transmitting and receiving local oscillators during array monitoring.

[0097] For example, the frequency source module outputs two local oscillator signals, one of which reaches the digital component after being distributed by a one-to-four power divider, and the local oscillator signal strength is not less than 0dBm, and the other is directly sent to the monitoring component.

[0098] 6. Fiber Optic Network

[0099] The fiber optic network amplifies the timing control signal received from the lightning control module and distributes it to each digital component. The high-speed fiber optic data is analyzed inside the digital component to complete the calculation and control of the uplink transmission phase. The echo data, self-test (BIT) information and control instructions from the display and control computer are packaged together and converted into high-speed fiber optic data, which is transmitted to the DBF via optical fiber.

[0100] For example, the optical fiber network amplifies the timing control signal through the optical power splitter and sends it to the digital component, monitoring component, detection component, frequency source module and DBF module, and transmits the echo data, BIT information and control command information to the DBF through the optical power splitter and beam combiner.

[0101] 7. Monitoring Link

[0102] The monitoring of the S-band waveguide crack digital phased array antenna array surface of the present invention adopts a combination of internal and external monitoring. The external monitoring is used to check the fault of the antenna unit and isolate the faulty antenna unit. The internal monitoring is used for the amplitude and phase error monitoring, calibration and calibration of the active channel of the antenna array surface.

[0103] The array monitoring link is mainly composed of a monitoring network, a matrix switch (not shown), a monitoring component, an external monitoring antenna (not shown) and a display and control computer (not shown). Figure 1 As shown, the antenna array high frequency box contains a monitoring component for internal and external monitoring of the array's transmission and reception. Reception and transmission are switched by a matrix switch to different links, which are divided into transmission links or reception links.

[0104] Transmitting internal monitoring refers to the internal monitoring of the array transmitting channel, which is used to manage the array health and find faulty channels in time. During transmitting internal monitoring, the monitored channel of the antenna array couples a part of the signal through the coupler, and sends it to the monitoring component through the monitoring network. The I and Q data output by the monitoring component are sent to DBF through the optical fiber network, and DBF is transmitted to the display and control computer through the optoelectronic network switch, and compared with the standard internal monitoring amplitude and phase values ​​to complete the calculation and calibration of the array amplitude and phase data.

[0105] During external monitoring, the signal radiated by the measured transmission channel is received by an external monitoring antenna independent of the array and sent to the monitoring component. The monitoring component outputs I and Q data to DBF and then to the display and control computer to complete phase correction.

[0106] During internal monitoring, the monitoring component outputs a radio frequency monitoring signal, which is sent to each coupler through the monitoring network and enters the array receiving channel through the coupler. The receiving channel outputs I and Q data to DBF. The display and control computer simultaneously completes the recording and calculation of the amplitude and phase calibration data of each array receiving channel, and compares it with the standard internal monitoring data.

[0107] When receiving external monitoring, the monitoring component outputs a radio frequency monitoring signal, which is sent to the array surface via the external monitoring antenna. After the array surface receives the radio frequency monitoring signal, it is amplified, filtered, and down-converted through the active receiving channel and converted into a digital signal. After DBF receives it, it is sent to the display and control computer to complete the calculation of the correction value.

[0108] The S-band waveguide slot digital phased array antenna array of the present invention adopts a one-dimensional digital transceiver architecture design in the pitch plane, and generates transmission excitation and digital reception behind each slot waveguide antenna.

[0109] The phase shifting of the phased array antenna is performed in the DDS module of the digital component during transmission and in the random access memory (RAM) of the digital component during reception. All is realized digitally, and there is no need to add a phase shifter in the TR component. The TR component is simpler and more reliable.

[0110] Array compensation is implemented digitally instead of using a phase shifter or attenuator, with a bit number of up to 16 bits. The consistency of the array channel is greatly improved after correction.

[0111] The array control signal is an optical signal, which greatly improves stability and reliability.

[0112] The formation of the transmit beam does not require the excitation distribution column feed, but is replaced by a local oscillator and clock power divider with a channel number of one to eight, eliminating the need for pre-stage duplexing. The formation of the receive beam is implemented digitally in the DBF, and the required 20 beams can be realized simultaneously, saving space and improving performance.

[0113] The digital transceiver channel is in multi-channel form, so that components can be shared, greatly reducing costs.

[0114] In another embodiment, a digital array radar comprises the S-band waveguide slot digital phased array antenna surface of the present invention.

[0115] Although the present invention has been disclosed as above with preferred embodiments, the embodiments are not intended to limit the present invention. Any equivalent changes or modifications made without departing from the spirit and scope of the present invention also belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the content defined by the claims of this application.

Claims

1. An S-band waveguide slot digital phased array antenna array, characterized in that: It includes waveguide, coupler, filter, TR component, digital component, frequency source plug-in box, local oscillator network, clock network, and optical fiber network; the frequency source plug-in box is provided with frequency source module, lightning control module, and DBF module; A plurality of the waveguides form an antenna array, and slots with opposite inclination angles are sequentially arranged at set intervals on the narrow side of the waveguide to form a traveling wave array, and the set interval is not equal to half the wavelength of the waveguide; the polarization form of the waveguide is horizontal polarization, and is divided into two types of waveguides, type A and type B, and the slots arranged on the two types of waveguides are the same, and the type A and type B waveguides are arranged adjacently and staggered on the antenna array plane; The filter is arranged between the coupler and the TR component to filter the received and transmitted signals; Each of the TR components includes a transmitting module, a plurality of RF transmitting channels, a receiving module and a plurality of RF receiving channels, and a plurality of TR components correspond to a digital component; The digital component includes several radio frequency interfaces, two of which are clock and local oscillator interfaces, and the rest are radio frequency receiving channel interfaces and radio frequency transmitting channel interfaces; The TR component and the digital component are connected via a radio frequency cable to achieve the transmission and reception conversion of the array surface; The mine control module converts the external working instructions into a timing control signal, and sends the timing control signal to each digital component of the array through the optical fiber network; when the array transmits, the timing control signal controls the frequency source module to output a pulse wave local oscillator signal of a single carrier frequency, a linear frequency modulation signal or a nonlinear frequency modulation signal of a certain frequency point, which is mixed and amplified by the digital component to the RF transmission channel, and stimulates the transmission module of the TR component to perform saturation amplification and filtering, and finally radiates to the external space through the waveguide line feed to form a transmission beam; when the array receives, the target reflection echo signal received by the antenna enters the receiving module of the TR component through the waveguide line feed, and after passive limiting and LNA low-noise amplification, reaches the digital component, and then undergoes mixing, intermediate frequency sampling, A / D conversion and DDC down-conversion, and the output digital signal is sent to the DBF module for processing to achieve digital phase matching and form an adaptive multi-beam; The local oscillator network provides a local oscillator signal for each digital component; The clock network provides a clock signal to each digital component; The optical fiber network amplifies the timing control signal and distributes it to each digital component, frequency source module and DBF module, and converts the digital signal output by the digital component into an optical signal and transmits it to the DBF module.

2. The S-band waveguide slot digital phased array antenna array according to claim 1, characterized in that: When the array is transmitting, the timing control signal controls the frequency source module to output a pulse wave local oscillator signal of a single carrier frequency, a linear frequency modulation signal or a nonlinear frequency modulation signal of a certain frequency point, which is mixed and amplified to the RF transmission channel by the digital component, and the transmitting module of the TR component is stimulated to perform saturation amplification and filtering, and finally fed to the external space through the waveguide to radiate and form a transmitting beam, including: The clock signal and local oscillator signal from the array are input to each digital component through the power division network. At the same time, the DDS in the RF transmission channel of each digital component generates an intermediate frequency signal of a certain frequency point according to the requirements of the received timing control signal. After mixing with the local oscillator signal on the mixer, it is filtered by a bandpass filter to generate the RF excitation signal required for power amplification and sent to each RF transmission channel of each TR component; and through switch control, the RF excitation signal enters the transmission module for power amplification, and the amplified power signal is output through the circulator, and finally transmitted to the waveguide slot antenna by the transmission feeder, and radiated to the external space; each transmission channel of the array performs power synthesis in space, and the transmission phase of each transmission channel weighted by the shaping weighting coefficient is controlled by DDS to form a corresponding shaped beam.

3. The S-band waveguide slot digital phased array antenna array according to claim 1, characterized in that: When the array receives, the target reflected echo signal received by the antenna enters the receiving module of the TR component through the waveguide line feed, reaches the digital component after passive limiting and LNA low-noise amplification, and then goes through mixing, intermediate frequency sampling, A / D conversion and DDC down-conversion, and the output digital signal is sent to the DBF module for processing to realize digital phase matching and form an adaptive multi-beam including: When the array receives, the target reflected echo signal received by the antenna enters the TR component, first passes through the circulator of the TR component, and the timing signal controls the T / R switch to switch to the receiving channel, and then passes through limiting and low-noise amplification in sequence, and enters the RF receiving channel of the digital component. After being mixed with the local oscillator signal transmitted by the frequency source module in the mixer, it is filtered by a bandpass filter to generate an intermediate frequency signal of a certain frequency point; the intermediate frequency signal is output as high-speed optical fiber data after A / D sampling and digital orthogonal down-conversion, and is transmitted to the DBF module through the optical fiber network for multi-beam synthesis.

4. The S-band waveguide slot digital phased array antenna array according to claim 1, characterized in that: It also includes a monitoring component, which is used for channel amplitude and phase calibration in the array monitoring mode, and for troubleshooting of antenna feed lines and components; The local oscillator network provides a local oscillator signal for each monitoring component; the clock network provides a clock signal for each monitoring component; The optical fiber network amplifies the timing control signal and distributes it to each monitoring component; The channel amplitude and phase calibration in the array monitoring mode includes: During the internal monitoring of transmission, the monitored transmission channel of the antenna array couples a part of the signal through the coupler and sends it to the monitoring component through the monitoring network. The I and Q data output by the monitoring component are sent to the DBF through the optical fiber network. The DBF transmits it to the external display and control computer through the optoelectronic network switch, and compares it with the standard monitoring amplitude and phase values ​​to complete the calculation and calibration of the array amplitude and phase data. During external monitoring of the transmission, the signal radiated by the measured transmission channel is received by the external monitoring antenna and sent to the monitoring component. The monitoring component outputs I and Q data to the DBF, and then to the display and control computer to complete the phase correction. During internal monitoring, the monitoring component outputs RF monitoring signals, which are sent to each coupler through the monitoring network and enter the array receiving channel through the coupler. The receiving channel outputs I and Q data to DBF, and the display and control computer simultaneously completes the recording and calculation of the amplitude and phase calibration data of each array receiving channel, and compares them with the standard internal monitoring data. When receiving external monitoring, the monitoring component outputs a radio frequency monitoring signal, which is radiated to the array surface through the external monitoring antenna. After the line feed receives the signal, it is amplified, filtered and down-converted through the receiving channel and converted into a digital signal. After DBF receives it, it is sent to the display and control computer to complete the calculation of the correction value.

5. The S-band waveguide slot digital phased array antenna array according to claim 1, characterized in that: It also includes a detection and receiving component, which detects external radiation environment signals in the airspace near the normal line of the main antenna and in the working frequency band; The clock network provides a clock signal for each detection and receiving component; The optical fiber network amplifies the timing control signal and distributes it to each detection and receiving component.

6. The S-band waveguide slot digital phased array antenna according to any one of claims 1 to 5, characterized in that: During phase scanning, the pitch phase difference within the array is The value is calculated as: in, is the free space wavelength at the corresponding frequency, is the spacing between waveguides, is the pitch scanning angle, is the pitch angle of the array, φ is the frequency sweep angle in azimuth that deviates from the array normal, and the calculation formula is: in, is the spacing between the slots of a single waveguide, is the free space wavelength at the corresponding frequency, is the length of the inner wall of the wide side of the waveguide.

7. A digital array radar, characterized in that: It comprises an S-band waveguide slot digital phased array antenna array surface according to any one of claims 1-6.

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