CN219180768U - Wide-bandwidth angle active scattering unit and measuring device for dual-station RCS performance thereof - Google Patents
Wide-bandwidth angle active scattering unit and measuring device for dual-station RCS performance thereof Download PDFInfo
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Abstract
The utility model provides a wide-bandwidth-angle active scattering unit and a measuring device for the performance of a double-station RCS (radar cross section), wherein the scattering unit comprises: a wide bandwidth angle antenna network and a broadband single port reflection amplifier network; the antenna network comprises: the planar spiral antenna and the microstrip index gradient balun are characterized in that an antenna arm feed point is connected with a balance end of the microstrip index gradient balun; the two supporting arms of the balun are respectively inserted into two supporting openings of the planar spiral antenna, and the antennas at the two supporting openings are not electrically connected with the balun; the reflective amplifier network comprises: the output end of the impedance transformation network is connected with the positive electrode of the negative resistance device and one end of the direct current bias network, and the negative electrode of the negative resistance device and the other end of the direct current bias network are grounded. The utility model has scattering gain in a wide angle range, and provides a performance measuring device of two active scattering units, which can actually measure the double-station RCS performance of the active scattering units.
Description
Technical Field
The utility model belongs to the field of signal propagation coverage enhancement, and particularly relates to a wide-bandwidth-angle active scattering unit and a measuring device for the performance of a double-station RCS (radio link control) of the wide-bandwidth-angle active scattering unit.
Background
The 5G enables 'everything interconnection' to be possible, and simultaneously, a series of practical application problems such as high cost, high energy consumption, increase of signal blind areas and the like are accompanied. The current 4G equipment is completely replaced by 5G equipment, the number of antenna surfaces is greatly increased, the signal coverage blind area is reduced, huge cost investment is brought, and meanwhile, a large amount of resource waste is accompanied, so that 4G and 5G coexist for a long time is common in the industry. In the process, a series of problems of shortage of antenna surface resources, larger signal coverage blind area, higher base station construction cost and energy consumption and the like are generated. The existing technology for enhancing the electric wave propagation signal has the problems of complex installation and deployment, limited blind supplementing capability, larger power consumption and the like, and has no low-power-consumption lightweight product capable of simultaneously solving the signal coverage blind area in a wide-frequency bandwidth angle range, and the existing problems of complex structure, expensive test equipment, complex test flow, larger measurement result error and the like of the active object scattering performance test device.
Disclosure of Invention
Aiming at the defects in the prior art, the utility model aims to provide a wide-bandwidth-angle active scattering unit and a measuring device for the performance of a double-station RCS (radio frequency control system), and aims to solve the problem of signal blind areas generated in the electric wave propagation process and provide an accurate and efficient testing device for active objects.
To achieve the above object, in a first aspect, the present utility model provides a wide bandwidth angle active scattering unit, comprising: a wide bandwidth angle antenna network and a broadband single port reflection amplifier network;
the wide bandwidth angle antenna network includes: the antenna comprises a planar spiral antenna and a microstrip index gradient balun, wherein an antenna arm feed point of the planar spiral antenna is connected with a balance end of the microstrip index gradient balun; the two support arms of the microstrip index gradient balun are respectively inserted into two support openings of the planar spiral antenna, and the planar spiral antenna at the two support openings is not electrically connected with the microstrip index gradient balun;
the broadband single port reflective amplifier network comprises: the device comprises an impedance transformation network, a negative resistance device and a direct current bias network, wherein the output end of the impedance transformation network is connected with the positive electrode of the negative resistance device and one end of the direct current bias network, and the negative electrode of the negative resistance device and the other end of the direct current bias network are grounded;
the unbalanced end of the microstrip index graded balun is connected with the input end of the impedance transformation network, and the characteristic impedance of the transmission line of the unbalanced end is the same as that of the transmission line of the input end of the impedance transformation network.
Alternatively, the negative resistance device is a tunnel diode, a gunn diode, or an avalanche diode, or the negative resistance device is a bipolar transistor or a field effect transistor having a positive feedback loop.
Optionally, the impedance transformation network comprises: the first microstrip line, the first capacitor, the second microstrip line, the first inductor, the third microstrip line, the second capacitor, the second inductor, the fourth microstrip line and the third inductor;
the first microstrip line, the first capacitor, the second microstrip line, the first inductor and the third microstrip line are sequentially connected in sequence to form a first serial branch; the input end of the first series branch is the input end of the first microstrip line, and the output end of the first series branch is the output end of the third microstrip line;
the fourth microstrip line and the third inductor are connected in series to form a second series branch; the input end of the second series branch is the input end of the fourth microstrip line, and the output end of the second series branch is the output end of the third inductor;
the second capacitor is connected with the second inductor in parallel to form a parallel branch; one end of the parallel branch is connected with the output end of the first serial branch, and the other end of the parallel branch is connected with the input end of the second serial branch; the input end of the first series branch forms the input end of the impedance transformation network, and the output end of the second series branch forms the output end of the impedance transformation network.
Optionally, the dc bias network includes: the device comprises a fourth inductor, a fifth microstrip line, a fifth inductor, a sixth microstrip line, a first voltage dividing resistor, a second voltage dividing resistor, a voltage stabilizing chip and a direct-current voltage source;
the fourth inductor, the fifth microstrip line, the fifth inductor, the sixth microstrip line and the first divider resistor are sequentially connected in series, the input end of the fourth inductor forms the input end of the direct current bias network,
the sixth microstrip line and the first voltage dividing resistor are connected with a second voltage dividing resistor, a voltage stabilizing chip and a direct current power supply in sequence at a series point; and the negative electrode of the direct current power supply and the non-series connection point of the first voltage dividing resistor are grounded.
Optionally, the first capacitor is a blocking capacitor, and is used for isolating direct current from entering the wide bandwidth angle antenna network.
In a second aspect, the present utility model provides a device for measuring the performance of a wide bandwidth angle active scattering unit double-station RCS, comprising: the broadband directional transmitting antenna, the broadband directional receiving antenna, the vector network analyzer, the data processing and control unit, the turntable, the plurality of insulating support frames, the standard scattering surface and the broadband wide-angle active scattering unit provided by the first aspect;
the plurality of insulating support frames are used for supporting the broadband directional transmitting antenna, the broadband directional receiving antenna, the turntable and the broadband wide angle active scattering unit or the standard scattering surface; the standard scattering surface is a square or round metal flat plate with a determined size; the turntable is used for bearing the wide-angle active scattering unit or the standard scattering surface which is supported by the insulating support frame;
the broadband directional transmitting antenna is used for transmitting signals to the broadband wide-angle active scattering unit or the standard scattering surface on the turntable, and the broadband directional receiving antenna is used for receiving the signals scattered by the broadband wide-angle active scattering unit or the standard scattering surface; the broadband directional transmitting antenna and the broadband directional receiving antenna are high-gain log-periodic antennas;
the turntable is respectively fixed with a tested wide-bandwidth-angle active scattering unit and a standard scattering surface, and rotates at a certain angular speed in the testing process; the spiral antenna surface in the wide-bandwidth-angle active scattering unit is perpendicular to the ground, so that the maximum radiation direction of the spiral antenna is parallel to the ground;
the first port of the vector network analyzer is connected with the broadband directional transmitting antenna through a transmission cable, the output sweep frequency signal is fed to the broadband directional transmitting antenna through the transmission cable, and the broadband directional transmitting antenna transmits signals to the tested broadband wide angle active scattering unit or standard scattering surface; a second port of the vector network analyzer is connected with a broadband directional receiving antenna and receives sweep frequency scattering signals from a tested active scattering unit or a standard scattering surface;
the data processing and control unit is connected with the vector network analyzer and the turntable and is used for controlling the turntable to rotate and processing the scattering signals received by the vector network analyzer to obtain the measurement result of the double-station RCS parameters of the wide-bandwidth angle active scattering unit.
Optionally, the second port of the vector network analyzer is connected with a broadband directional receiving antenna, receives the sweep scattering signals from the tested active scattering unit or standard scattering surface, and outputs corresponding transmission coefficients respectively
、
； wherein ,/>
Indicating the angle between the maximum gain direction of the broadband directional transmitting antenna and the normal of the scattering plane,
representing the angle between the maximum gain direction and the vertical direction of the wideband directional transmitting antenna, < >>
Representing the angle between the maximum gain direction of the broadband directional receiving antenna and the normal of the scattering plane,/for the broadband directional receiving antenna>
An included angle between the maximum gain direction and the vertical direction of the broadband directional receiving antenna is shown;
the double-station RCS parameter of the measured wide-bandwidth-angle active scattering unit is calculated by adopting the following formula:
wherein ,
is the standard scattering surface double station RCS value.
In a third aspect, the present utility model provides a device for measuring the performance of a wide bandwidth angle active scattering unit double-station RCS, comprising: the wide-bandwidth-angle active scattering unit, the standard scattering surface, the unmanned aerial vehicle carrying platform, the ground receiving processing station, the ground broadband modulation signal transmitter and the transmitting antenna provided in the first aspect;
the ground reception processing station includes: an array receiving antenna and an array receiver; the array receiving antenna adopts a monopole omnidirectional antenna as an array element, the array receiver comprises a plurality of broadband superheterodyne receiving channels, each receiving channel is provided with a local oscillation source, and local oscillation of all receiving channels can be locked in a same-frequency and same-phase state through external input of a reference clock and synchronous trigger pulses;
the unmanned aerial vehicle carrying platform is used for respectively carrying the tested wide-bandwidth-angle active scattering unit and the standard scattering surface to an open space;
the ground broadband modulation signal transmitter and the transmitting antenna are used for transmitting broadband modulation signals to the tested broadband wide angle active scattering unit or the standard scattering surface;
the ground receiving processing station is used for receiving scattered wave signals from the tested wide-bandwidth angle active scattering unit or the standard scattering surface and receiving direct wave signals directly from the ground wide-bandwidth modulation signal transmitter so as to obtain measurement results of the two-station RCS parameters of the wide-bandwidth angle active scattering unit.
Optionally, the ground reception processing station further comprises: the system comprises an array synchronous acquisition unit, an array digital preprocessing unit, a super-resolution DOA estimation unit, a direct wave/scattered wave separation unit, a range Doppler processing unit and a double-station RCS calculation unit;
the array synchronous acquisition unit carries out synchronous sampling quantization on multiple paths of intermediate frequency signals output by the array receiver;
the array digital preprocessing unit carries out digital down-conversion and filtering extraction processing on the multipath digital intermediate frequency signals output by the array synchronous acquisition unit and outputs multipath IQ complex baseband signals;
the super-resolution DOA estimation unit processes the multi-channel IQ complex baseband signals output by the array digital preprocessing unit and estimates the incoming wave directions of the direct wave and the scattered wave;
the direct wave/scattered wave separation unit carries out digital wave beam forming processing on the multiple IQ complex baseband signals output by the array digital preprocessing unit and outputs IQ complex baseband signals of direct waves and scattered waves respectively;
the distance Doppler processing unit calculates a two-dimensional weighted fuzzy function of the direct wave and scattered wave IQ complex baseband signals output by the direct wave/scattered wave separation unit, and takes out an abscissa and an ordinate corresponding to a spectrum peak point of the distance spectrum from the two-dimensional weighted fuzzy function so as to determine a propagation travel difference value of the scattered wave and the direct wave and a relative intensity value of the scattered signal.
The double-station RCS calculation unit calculates the relative intensity of the scattered signal corresponding to the standard scattering surface according to the incoming wave direction of the signal estimated by the super-resolution DOA estimation unit and the scattered signal output by the range Doppler processing unit
Relative intensity of scattered signal corresponding to the wide-angle active scattering element to be measured>
, wherein ,/>
、/>
Respectively representing azimuth angle and pitch angle of an incident wave incident from a broadband directional transmitting antenna to a scattering surface, +.>
、/>
Respectively representing azimuth angle and pitch angle of scattered waves incident to the central point of the antenna array of the ground receiving and processing station from the scattering surface; />
The dual-station RCS value of the measured wide-bandwidth-angle active scattering unit is calculated using:
wherein ,
is the standard scattering surface double station RCS value.
Optionally, the ground reception processing station further comprises: a display unit and a wireless communication unit;
the display unit is used for displaying the azimuth angle and the pitch angle of the incoming wave directions of the direct wave and the scattered wave calculated by the super-resolution DOA estimation unit, the distance Doppler spectrum between the direct wave and the scattered wave output by the distance Doppler processing unit and the double-station RCS value of the measured wide-angle active scattering unit output by the double-station RCS calculation unit in real time;
the wireless communication unit is used for sending position and attitude control instructions to the unmanned aerial vehicle carrying platform and receiving position coordinate information downloaded by the unmanned aerial vehicle carrying platform in real time.
In general, the above technical solutions conceived by the present utility model have the following beneficial effects compared with the prior art:
the utility model provides a wide-angle active scattering unit and a measuring device for the performance of a double-station RCS thereof, which have scattering gain in a wide-angle range, are used for improving the coverage effect of 5G mobile communication and can greatly reduce the number of base stations required to be built. The wide-angle scattering gain effect is generated by directly connecting the wide-bandwidth planar spiral antenna with a reflective amplifier, and the reflective amplifier can enhance signals in all directions received by the antenna, so that the angular coverage of the wide-bandwidth active scattering unit is consistent with the beam width of the planar spiral antenna.
The utility model provides a wide-bandwidth angle active scattering unit and a measuring device for the performance of a double-station RCS thereof, which have larger scattering gain in a wide-bandwidth range, can increase the deployment distance of base stations in the signal propagation process, and further reduce the number of the base stations. This effect results from the exact matching of the antenna impedance transformation network proposed in the present utility model with the impedance transformation network in the reflective amplifier. The impedance transformation network structure provided by the utility model ensures that the antenna network and the negative resistance device have good impedance matching relation in a wide frequency band, thereby generating larger reflection gain.
The wide-bandwidth-angle active scattering unit provided by the utility model has extremely low power consumption, and can assist the mobile communication technology to realize the development goal of green double carbon. This is because the active negative resistance devices used in active scattering cells operate in the negative resistance region with very low bias voltages, resulting in higher reflection gains.
Compared with the existing testing device, the connection relation of the measuring device for the wide-bandwidth angle active scattering unit in the microwave dark room is reduced, the number of receiving devices is reduced, the testing space is reduced, and the testing flow is simplified. The existing testing device is provided with a plurality of receiving devices which are arranged around a circle of the to-be-tested piece at equal angle intervals, and the to-be-tested piece is fixed in the center and does not rotate. The microwave darkroom measuring device provided by the utility model only needs one transmitting antenna and one receiving antenna, the included angles between the transmitting antenna and the receiving antenna and the to-be-measured piece are fixed, the to-be-measured piece is placed in the center of the turntable, the turntable rotates according to a certain angular frequency, the ratio of the signal intensity of the transmitting antenna and the receiving antenna is recorded according to a certain angular interval, and the scattering characteristic of the wide-bandwidth angle active scattering unit can be obtained through simple data processing.
The measuring device for the wide-bandwidth angle active scattering unit in the open space is provided with no existing related device at present. The open space testing device provided by the utility model has stronger flexibility, the wide-bandwidth-angle active scattering unit to be tested is suspended by the unmanned aerial vehicle, and the position and the posture of the unmanned aerial vehicle can be adjusted according to the actual testing environment, so that the position relation between a piece to be tested and a receiving station and the transmitting station can be adjusted, the ground receiving processing station has a high-precision and high-resolution signal processing function, the direction and the intensity of direct waves and scattering waves can be effectively distinguished, and further the double-station RCS performance and the ground scattering field distribution condition of the wide-bandwidth-angle active scattering unit can be evaluated.
Drawings
FIG. 1 is a schematic diagram of the composition and structure of a wide bandwidth angle active scattering cell according to an embodiment of the present utility model;
FIG. 2 is a block diagram of a single port reflection amplifier circuit provided by an embodiment of the present utility model;
FIG. 3 is a diagram showing the connection relation of the microwave darkroom measuring device according to the embodiment of the present utility model;
FIG. 4 is a schematic diagram of an open space measurement device according to an embodiment of the present utility model;
the same reference numbers are used throughout the drawings to reference like elements or structures, wherein: 100 represents a planar spiral antenna, 200 represents a microstrip index progressive balun, and 300 represents a single-port reflection amplifying circuit; 301 represents an impedance transformation network, 302 represents a negative resistance device, 303 represents a direct current bias network, 3031 represents a voltage stabilizing chip, tl_m0 represents a first microstrip line in the impedance transformation network, c_m0 represents a first capacitance in the impedance transformation network, tl_m1 represents a second microstrip line in the impedance transformation network, l_m1 represents a first inductance in the impedance transformation network, tl_m2 represents a third microstrip line in the impedance transformation network, c_m1 represents a second capacitance in the impedance transformation network, l_m2 represents a second inductance in the impedance transformation network, tl_m3 represents a fourth microstrip line in the impedance transformation network, l_m3 represents a third inductance in the impedance transformation network, TJ represents a T-type adapter, l_d1 represents a first inductance in the direct current bias network, c_d1 represents a first capacitance in the direct current bias network, tl_d1 represents a first inductance in the direct current bias network, l_d2 represents a second inductance in the direct current bias network, tl_d2 represents a second microstrip line in the direct current bias network, l_d2 represents a voltage dividing resistance in the direct current bias network, and r_d2 represents a voltage dividing resistance in the direct current bias network; 1 represents a wide bandwidth angle active scattering unit, 2 represents a standard scattering surface, 3 represents a turntable, 4 represents a transmitting antenna, 5 represents a receiving antenna, 6 represents a vector network analyzer, and 7 represents a data processing and control unit; 11 denotes a drone carrying platform, 12 denotes a ground bandwidth modulation signal transmitter, 13 denotes a ground reception processing station, 1301 denotes an array reception antenna, 1302 denotes an array receiver, 1303 denotes an array synchronization acquisition unit, 1304 denotes an array digital preprocessing unit, 1305 denotes a direct wave/scattered wave separation unit, 1306 denotes a super-resolution DOA estimation unit, 1307 denotes a range-doppler processing unit, 1308 denotes a two-station RCS calculation unit, 1309 denotes a display unit, 1310 denotes a wireless communication unit, 1311 denotes a wireless communication antenna.
Detailed Description
For convenience of understanding, the following description will explain and describe english abbreviations and related technical terms related to the embodiments of the present application.
Embodiments of the present application are described below with reference to the accompanying drawings in the embodiments of the present application.
Fig. 1 is a schematic diagram of the composition structure of a wide-bandwidth-angle active scattering unit according to the present utility model, as shown in fig. 1, which uses a planar spiral antenna 100 as a device for receiving and radiating signals from the scattering unit. The helical structure of the planar helical antenna 100 is a combination of equiangular and archimedes helices. One end of the micro-strip index graded balun 200 is a balanced end, can be approximately seen as a parallel double line, is contacted with feed points of two antenna arms in the center of the planar spiral antenna 100, and the other end of the balun 200 is an unbalanced end, and can be approximately seen as a micro-strip line structure. In a specific example, the linewidth of the microstrip line having a linewidth of 50Ω at the edge is directly connected to the input port of the reflection amplifier 300. The two supporting arms of the microstrip index gradient balun 200 are inserted into the supporting openings of the planar spiral antenna, and no electrical connection exists between the two supporting arms, so that the microstrip index gradient balun is only used for fixing and supporting. The microstrip index gradient balun 200 serves to transform the balanced structure of the two feeding points in the center of the helical antenna 100 into the unbalanced structure of the port of the reflective amplifier 300, and at the same time, the microstrip index gradient balun 200 serves as an impedance transformation of the antenna network, transforming the high input impedance of the plane of the helical antenna 100 into the low input impedance of 50Ω of the port of the reflective amplifier 300.
Fig. 2 is a block diagram of a single-port reflection amplifier circuit provided by the present utility model, and as shown in fig. 2, the single-port reflection amplifier circuit is entirely divided into three parts: an impedance transformation network 301, a DC bias network 303, and a negative resistance 302. The reflective amplifier circuit is printed on the same dielectric substrate as the balun and is directly connected with the unbalanced terminal of the balun.
As shown in fig. 2, in the impedance transformation network 301: tl_m0 represents a first microstrip line in the impedance transformation network, c_m0 represents a first capacitance in the impedance transformation network, tl_m1 represents a second microstrip line in the impedance transformation network, l_m1 represents a first inductance in the impedance transformation network, tl_m2 represents a third microstrip line in the impedance transformation network, c_m1 represents a second capacitance in the impedance transformation network, l_m2 represents a second inductance in the impedance transformation network, tl_m3 represents a fourth microstrip line in the impedance transformation network, and l_m3 represents a third inductance in the impedance transformation network;
specifically, the first microstrip line tl_m0, the first capacitor c_m0, the second microstrip line tl_m1, the first inductor l_m1 and the third microstrip line tl_m2 are sequentially connected in sequence to form a first serial branch; the input end of the first series branch is the input end of the first microstrip line TL_m0, and the output end of the first series branch is the output end of the third microstrip line TL_m2;
the fourth microstrip line TL_m3 and the third inductor L_m3 are connected in series to form a second series branch; the input end of the second series branch is the input end of the fourth microstrip line TL_m3, and the output end is the output end of the third inductor L_m3;
the second capacitor C_m1 is connected with the second inductor L_m2 in parallel to form a parallel branch; one end of the parallel branch is connected with the output end of the first serial branch, and the other end of the parallel branch is connected with the input end of the second serial branch; the input of the first series leg constitutes the input of the impedance transformation network 301 and the output of the second series leg constitutes the output of the impedance transformation network 301.
Specifically, as shown in fig. 2, in the dc offset network 303: l_d1 represents a first inductance in the direct current bias network, C_d1 represents a first capacitance in the direct current bias network, TL_d1 represents a first microstrip line in the direct current bias network, L_d2 represents a second inductance in the direct current bias network, TL_d2 represents a second microstrip line in the direct current bias network, C_d2 represents a second capacitance in the direct current bias network, R1 represents a first voltage dividing resistor, R2 represents a second voltage dividing resistor, and DC represents a direct current voltage source. The specific connection is drawn with reference to fig. 2, and will not be described herein.
In a specific embodiment, the impedance transformation network circuit 301 is configured to transform the input impedance of the reflective amplifier port 50Ω to the input impedance of the circuit in which the negative resistance device is located, where the portion is formed by a capacitor, an inductor, and microstrip lines of different sizes: the impedance transformation network 301 is composed of lumped parameter elements (capacitance, inductance) and distributed parameter elements (microstrip lines). The microstrip line at the connection of the impedance transformation network 301 and the antenna network is 50 ohm line width, the other transmission lines with different sizes are used for connecting capacitance and inductance on one hand, and on the other hand, the capacitor C_m0 is used for isolating the direct current signal from entering the antenna end, and the capacitors and the inductances with different parameters are connected in series and in parallel to tune the impedance of the circuit, so that the impedance transformation effect is preset. The negative resistance device 302 may use a tunnel diode, a gunn diode or an avalanche diode, and a bipolar transistor or a field effect transistor having a positive feedback loop, to which a suitable bias voltage is added to operate in a negative resistance region so that the real part of the impedance of the entire circuit is negative. The positive electrode of the negative resistance device 302 is connected to the microstrip line T-shaped joint TJ, connected to the impedance transformation network 301 and the direct bias network 303, and the negative electrode is directly grounded, so as to provide a broadband negative resistance effect. The DC bias network provides a proper DC bias voltage for the negative resistance device, so that the negative resistance device stably works in a negative resistance area. The choke inductance is used for restraining alternating current signals mixed in the direct current voltage source, and the decoupling capacitor can isolate the alternating current signals and prevent the alternating current signals from entering the direct current voltage source. Because the DC bias voltage required by the negative resistance device is smaller, and the output voltage of the DC power supply can be reduced along with the use duration in the actual use process, a voltage stabilizing chip and a voltage dividing resistor are required, so that the DC bias voltage is stabilized on the required DC voltage.
The impedance transformation network 301 determines the frequency point, bandwidth and gain of the single port reflective amplifier. The parameters of the impedance transformation network element in the reflection amplifier circuit are optimized, and the direct-current bias voltage of the negative resistance device is required to be combined, so that the equivalent dynamic admittance of the negative resistance device is changed due to different bias voltages. Meanwhile, as the negative resistance characteristic of the device is only caused by a negative slope curve segment in the volt-ampere characteristic curve, the selection of the bias point also directly influences the non-harmonic distortion dynamic range SFDR and intermodulation distortion characteristic of the reflecting amplifier. Therefore, the circuit design and parameter optimization are required to be carried out by comprehensively adopting the small-signal frequency domain steady-state analysis and the large-signal harmonic balance analysis (or intermodulation wave balance analysis) technology, so that the designed reflection amplifier meets the requirements of the wide-bandwidth-angle active scattering unit on the active amplifying circuit in the indexes of the working frequency range, the gain, the undistorted dynamic range and the like.
Fig. 3 is a connection diagram of the microwave darkroom measuring device provided by the utility model, as shown in fig. 3, an insulating support rod is vertically placed in the center of a turntable 3 to fix a wide-bandwidth-angle active scattering unit 1 to be measured and a standard scattering surface 2, and a spiral antenna surface in the fixed wide-bandwidth-angle active scattering unit 1 is vertical to the ground, so that the maximum radiation direction of the spiral antenna is parallel to the ground. The turntable 3 is connected with a data processing and control unit 7 through a turntable control line, and the data processing and control unit 7 controls the rotation direction and rotation speed of the turntable 3. The wideband directional transmitting antenna 4 is a high-gain log-periodic antenna, its feed port is connected to the first port of the vector network analyzer 6 through a low-loss transmission line, and the wideband directional receiving antenna 5 is a high-gain log-periodic antenna, its feed port is connected to the second port of the vector network analyzer 6 through a low-loss transmission line.
The broadband directional transmitting antenna 4 and the broadband directional receiving antenna 5 are respectively fixed on corresponding insulating support rods, and the geometric centers of the broadband wide angle active scattering unit 1 or the standard scattering surface 2, the broadband directional transmitting antenna 4 and the broadband directional receiving antenna 5 are at the same horizontal height. The first port of the vector network analyzer 6 outputs a swept signal, which reaches the feed port of the broadband directional transmitting antenna 4 through the low-loss transmission line, the broadband directional transmitting antenna 4 transmits a signal to the broadband wide-angle active scattering unit 1 or the standard scattering surface 2, the broadband wide-angle active scattering unit 1 amplifies the received signal by reflection and radiates the received signal outwards, and the broadband directional receiving antenna 5 receives the signal radiated outwards by the broadband wide-angle active scattering unit 1 or the standard scattering surface 2 and inputs the amplified swept signal to the second port of the vector network analyzer 6 through the low-loss transmission line. The included angle between the maximum gain direction of the broadband directional transmitting antenna 4 and the normal line of the broadband angle active scattering unit plane 1 or the standard scattering surface 2 is
The maximum gain direction of the broadband directional receiving antenna 5 is normal to the broadband wide angle active scattering element plane 1 or the standard scattering surface 2The included angle is->
，/>
And->
The sum is a constant +.>
. The data processing and control unit 7 is connected with a data transmission port of the vector network analyzer 6, and the transmission coefficient measured by the vector network analyzer 6 is input into the data processing and control unit 7.
In the measuring process, firstly, a standard scattering surface is fixed on an insulating supporting rod of a turntable, a data processing and control unit controls a first port of a vector network analyzer to transmit a sweep frequency signal to a transmitting antenna through a data transmission line, and meanwhile, the data processing and control unit controls the turntable to rotate along a specified direction at a certain angular speed through a turntable control line. And in the rotating process of the turntable, the receiving antenna receives the amplified signal radiated by the standard scattering surface and inputs the amplified signal into the vector network for analyzing the second port. In the process of rotating the turntable for one circle, the vector network analyzer inputs the corresponding transmission coefficients under different angles into the data processing and control unit through the data transmission port according to a certain angle interval. After one turn of the turntable, the measurement is stopped. Next, the wide-angle active scattering unit to be measured is fixed on the insulating support bar of the turntable, using the same procedure as described above. And calculating in the data processing and control unit according to the signal data obtained by the two measurements and the angle information of the turntable to obtain the scattering performance of the wide-bandwidth angle active scattering unit. The brief deduction calculation flow of the data processing procedure is as follows:
let the double-station RCS of the active scattering unit of the wide angle of the measured broadband be
. The RCS of the standard scattering surface is calculated to be +.>
。/>
The standard scattering surface is fixed on the turntable, and the included angle between the transmitting antenna and the normal direction of the standard scattering surface is +.>
The angle between the receiving antenna and the normal direction of the standard scattering surface is
And measuring the obtained transmission coefficient by the vector network analyzer. />
The active scattering unit with a fixed wide bandwidth angle on the turntable is represented, and the included angle between the transmitting antenna and the normal direction of the active scattering unit with the wide bandwidth angle is +.>
The angle between the receiving antenna and the normal direction of the wide-bandwidth-angle active scattering unit is +.>
And measuring the obtained transmission coefficient by the vector network analyzer. There is thus the following equation:
the double-station RCS for obtaining the measured wide-angle active scattering unit is as follows:
fig. 4 is a structural connection diagram of an open space testing apparatus according to the present utility model, as shown in fig. 4, the open space testing apparatus includes: the system comprises a tested wide-bandwidth angle active scattering unit, a standard scattering surface, an unmanned aerial vehicle carrying platform 11, a ground receiving processing station 13 and a ground wide-bandwidth modulation signal transmitter 12. And the unmanned aerial vehicle lifts the standard scattering surface and the wide-bandwidth angle active scattering unit to the same point. A transmitter located on the ground transmits a wideband modulated signal via an omni-directional antenna or a low gain directional antenna, while a ground receiving processing station receives and processes the direct wave signal and the scattered wave signal scattered by an overhead scatterer (standard metal sphere or plane, wideband angle active scattering unit).
Considering that the scattered wave propagation path attenuation may be much larger than the direct wave path, the ground receiving processing station has an array receiving antenna 1301, an array receiver 1302, an array synchronization acquisition unit 1303, an array digital preprocessing unit 1304, a super resolution DOA estimation unit 1306, a direct wave/scattered wave separation unit 1305, a range-doppler processing unit 1307, a dual-station RCS calculation unit 1308, a display unit 1309, a wireless communication unit 1310 with the drone, and a wireless communication antenna 1311 (i.e., a drone remote control communication unit).
The array receiving antenna 1301 adopts monopole omni-directional antennas as array elements to form an 8-array element or 16-array element uniform circular antenna array, and is used for receiving direct wave signals from a ground transmitter and scattered wave signals from a wide-bandwidth angle active scattering surface or a standard scattering surface; the array receiver 1302 performs preprocessing on signals received by the array receiving antenna 1301, wherein the signals comprise 8 or 16 broadband superheterodyne receiving channels with consistent performance, each receiving channel is provided with a local vibration source, and can be locked in a same-frequency and same-phase state through an external input reference clock and a synchronous trigger pulse; the array synchronous acquisition unit 1301 carries out high-precision synchronous sampling quantization on multiple paths of intermediate frequency signals output by the array receiver; the array digital preprocessing unit 1304 performs digital down-conversion and filtering extraction processing on the multiple paths of digital intermediate frequency signals output by the array synchronous acquisition unit, and outputs multiple paths of IQ complex baseband signals; the super-resolution DOA estimation unit 1306 estimates the number of sources of incoming wave signals by using an information theory criterion on the multi-channel IQ complex baseband signals output by the array digital preprocessing unit, and adopts a multi-signal classification algorithm to super-resolution estimate the incoming wave direction of each signal, wherein the incoming wave direction comprises an incoming wave azimuth angle and a pitch angle, and the incoming wave directions respectively correspond to the directions of direct waves and scattered waves; direct toThe wave/scattered wave separating unit 1305 uses a digital beam forming algorithm to the multi-channel IQ complex baseband signals output by the array digital preprocessing unit to calculate IQ complex baseband signals of direct waves and scattered waves; the distance Doppler processing unit 1307 calculates a two-dimensional weighted fuzzy function on the direct wave and scattered wave IQ complex baseband signals output by the direct wave/scattered wave separation unit, and extracts an abscissa and an ordinate corresponding to a spectrum peak point of the distance spectrum from the two-dimensional weighted fuzzy function, wherein the abscissa and the ordinate correspond to a propagation travel difference value of the scattered wave and the direct wave and a relative intensity value of the scattered signal respectively; the dual-station RCS calculation unit 1308 outputs the relative strength of the scattered signal corresponding to the standard scattering surface according to the distance Doppler processing unit
Relative intensity of scattered signal corresponding to the wide-angle active scattering element to be measured>
The dual-station RCS value of the measured wide-bandwidth-angle active scattering unit is calculated using:
wherein ,
is the standard scattering surface double station RCS value.
The result of the two-station RCS calculation unit is compared with the position coordinates downloaded by the unmanned aerial vehicle in the wireless communication unit 1310 of the unmanned aerial vehicle, and the result is presented in the display unit 1309.
The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (10)
1. A wide bandwidth angle active scattering element, comprising: a wide bandwidth angle antenna network and a broadband single port reflection amplifier network;
the wide bandwidth angle antenna network includes: the antenna comprises a planar spiral antenna and a microstrip index gradient balun, wherein an antenna arm feed point of the planar spiral antenna is connected with a balance end of the microstrip index gradient balun; the two support arms of the microstrip index gradient balun are respectively inserted into two support openings of the planar spiral antenna, and the planar spiral antenna at the two support openings is not electrically connected with the microstrip index gradient balun;
the broadband single port reflective amplifier network comprises: the device comprises an impedance transformation network, a negative resistance device and a direct current bias network, wherein the output end of the impedance transformation network is connected with the positive electrode of the negative resistance device and one end of the direct current bias network, and the negative electrode of the negative resistance device and the other end of the direct current bias network are grounded;
the unbalanced end of the microstrip index graded balun is connected with the input end of the impedance transformation network, and the characteristic impedance of the transmission line of the unbalanced end is the same as that of the transmission line of the input end of the impedance transformation network.
2. The broad bandwidth angle active scattering cell of claim 1, wherein the negative resistance device is a tunnel diode, a gunn diode, or an avalanche diode, or the negative resistance device is a bipolar transistor or a field effect transistor with a positive feedback loop.
3. The wide bandwidth angle active scattering cell of claim 1 or 2, wherein the impedance transformation network comprises: the first microstrip line, the first capacitor, the second microstrip line, the first inductor, the third microstrip line, the second capacitor, the second inductor, the fourth microstrip line and the third inductor;
the first microstrip line, the first capacitor, the second microstrip line, the first inductor and the third microstrip line are sequentially connected in sequence to form a first serial branch; the input end of the first series branch is the input end of the first microstrip line, and the output end of the first series branch is the output end of the third microstrip line;
the fourth microstrip line and the third inductor are connected in series to form a second series branch; the input end of the second series branch is the input end of the fourth microstrip line, and the output end of the second series branch is the output end of the third inductor;
the second capacitor is connected with the second inductor in parallel to form a parallel branch; one end of the parallel branch is connected with the output end of the first serial branch, and the other end of the parallel branch is connected with the input end of the second serial branch; the input end of the first series branch forms the input end of the impedance transformation network, and the output end of the second series branch forms the output end of the impedance transformation network.
4. The wide bandwidth angle active scattering cell of claim 1 or 2, wherein the dc bias network comprises: the device comprises a fourth inductor, a fifth microstrip line, a fifth inductor, a sixth microstrip line, a first voltage dividing resistor, a second voltage dividing resistor, a voltage stabilizing chip and a direct-current voltage source;
the fourth inductor, the fifth microstrip line, the fifth inductor, the sixth microstrip line and the first divider resistor are sequentially connected in series, the input end of the fourth inductor forms the input end of the direct current bias network,
the sixth microstrip line and the first voltage dividing resistor are connected with a second voltage dividing resistor, a voltage stabilizing chip and a direct current power supply in sequence at a series point; and the negative electrode of the direct current power supply and the non-series connection point of the first voltage dividing resistor are grounded.
5. A wide bandwidth angle active scattering cell according to claim 3, wherein the first capacitance is a dc blocking capacitance for isolating dc from entering the wide bandwidth angle antenna network.
6. A device for measuring the performance of a wide bandwidth angle active scattering element double station RCS, comprising: a broadband directional transmitting antenna, a broadband directional receiving antenna, a vector network analyzer, a data processing and control unit, a turntable, a plurality of insulating support frames, a standard scattering surface, and a broadband wide angle active scattering unit according to any one of claims 1 to 5;
the plurality of insulating support frames are used for supporting the broadband directional transmitting antenna, the broadband directional receiving antenna, the turntable and the broadband wide angle active scattering unit or the standard scattering surface; the standard scattering surface is a square or round metal flat plate with a determined size; the turntable is used for bearing the wide-angle active scattering unit or the standard scattering surface which is supported by the insulating support frame;
the broadband directional transmitting antenna is used for transmitting signals to the broadband wide-angle active scattering unit or the standard scattering surface on the turntable, and the broadband directional receiving antenna is used for receiving the signals scattered by the broadband wide-angle active scattering unit or the standard scattering surface; the broadband directional transmitting antenna and the broadband directional receiving antenna are high-gain log-periodic antennas;
the turntable is respectively fixed with a tested wide-bandwidth-angle active scattering unit and a standard scattering surface, and rotates according to a preset angular speed in the testing process; the spiral antenna surface in the wide-bandwidth-angle active scattering unit is perpendicular to the ground, so that the maximum radiation direction of the spiral antenna is parallel to the ground;
the first port of the vector network analyzer is connected with the broadband directional transmitting antenna through a transmission cable, the output sweep frequency signal is fed to the broadband directional transmitting antenna through the transmission cable, and the broadband directional transmitting antenna transmits signals to the tested broadband wide angle active scattering unit or standard scattering surface; a second port of the vector network analyzer is connected with a broadband directional receiving antenna and receives sweep frequency scattering signals from a tested active scattering unit or a standard scattering surface;
the data processing and control unit is connected with the vector network analyzer and the turntable and is used for controlling the turntable to rotate and processing the scattering signals received by the vector network analyzer to obtain the measurement result of the double-station RCS parameters of the wide-bandwidth angle active scattering unit.
7. The measuring apparatus according to claim 6, wherein the second port of the vector network analyzer is connected to a broadband directional receiving antenna for receiving the swept scattering signals from the active scattering unit or standard scattering surface under test and outputting corresponding signals, respectivelyCoefficient of transmission
、/>
； wherein ,/>
Representing the angle between the maximum gain direction of the broadband directional transmitting antenna and the normal of the scattering plane,/for the broadband directional transmitting antenna>
Representing the angle between the maximum gain direction and the vertical direction of the wideband directional transmitting antenna, < >>
Representing the angle between the maximum gain direction of the broadband directional receiving antenna and the normal of the scattering plane,/for the broadband directional receiving antenna>
An included angle between the maximum gain direction and the vertical direction of the broadband directional receiving antenna is shown;
the double-station RCS parameter of the measured wide-bandwidth-angle active scattering unit is calculated by adopting the following formula:
wherein ,
is the standard scattering surface double station RCS value.
8. A device for measuring the performance of a wide bandwidth angle active scattering element double station RCS, comprising: the wide bandwidth angle active scattering unit, standard scattering surface, unmanned aerial vehicle carrying platform, ground reception processing station, ground broadband modulation signal transmitter, and transmitting antenna of any one of claims 1 to 5;
the ground reception processing station includes: an array receiving antenna and an array receiver; the array receiving antenna adopts a monopole omnidirectional antenna as an array element, the array receiver comprises a plurality of broadband superheterodyne receiving channels, each receiving channel is provided with a local oscillation source, and local oscillation of all receiving channels can be locked in a same-frequency and same-phase state through external input of a reference clock and synchronous trigger pulses;
the unmanned aerial vehicle carrying platform is used for respectively carrying the tested wide-bandwidth-angle active scattering unit and the standard scattering surface to an open space;
the ground broadband modulation signal transmitter and the transmitting antenna are used for transmitting broadband modulation signals to the tested broadband wide angle active scattering unit or the standard scattering surface;
the ground receiving processing station is used for receiving scattered wave signals from the tested wide-bandwidth angle active scattering unit or the standard scattering surface and receiving direct wave signals directly from the ground wide-bandwidth modulation signal transmitter so as to obtain measurement results of the two-station RCS parameters of the wide-bandwidth angle active scattering unit.
9. The measurement device of claim 8, wherein the ground reception processing station further comprises: the system comprises an array synchronous acquisition unit, an array digital preprocessing unit, a super-resolution DOA estimation unit, a wave separation unit, a range Doppler processing unit and a double-station RCS calculation unit;
the array synchronous acquisition unit carries out synchronous sampling quantization on multiple paths of intermediate frequency signals output by the array receiver;
the array digital preprocessing unit carries out digital down-conversion and filtering extraction processing on the multipath digital intermediate frequency signals output by the array synchronous acquisition unit and outputs multipath IQ complex baseband signals;
the super-resolution DOA estimation unit processes the multi-channel IQ complex baseband signals output by the array digital preprocessing unit and estimates the incoming wave directions of the direct wave and the scattered wave;
the wave separation unit carries out digital wave beam forming processing on the multiple IQ complex baseband signals output by the array digital preprocessing unit and outputs IQ complex baseband signals of direct waves and scattered waves respectively;
the distance Doppler processing unit calculates a two-dimensional weighted fuzzy function of the direct wave and scattered wave IQ complex baseband signals output by the wave separation unit, and takes out an abscissa and an ordinate corresponding to a spectrum peak point of a distance spectrum from the two-dimensional weighted fuzzy function so as to determine a propagation travel difference value of the scattered wave and the direct wave and a relative intensity value of the scattered signal;
the double-station RCS calculation unit calculates the relative intensity of the scattered signal corresponding to the standard scattering surface according to the incoming wave direction of the signal estimated by the super-resolution DOA estimation unit and the scattered signal output by the range Doppler processing unit
Relative intensity of scattered signal corresponding to the wide-angle active scattering element to be measured>
, wherein ,/>
、/>
Respectively representing azimuth angle and pitch angle of an incident wave incident from a broadband directional transmitting antenna to a scattering surface, +.>
、/>
Respectively representing azimuth angle and pitch angle of scattered waves incident to the central point of the antenna array of the ground receiving and processing station from the scattering surface;
the dual-station RCS value of the measured wide-bandwidth-angle active scattering unit is calculated using:
wherein ,
is the standard scattering surface double station RCS value.
10. The measurement device of claim 9, wherein the ground reception processing station further comprises: a display unit and a wireless communication unit;
the display unit is used for displaying the azimuth angle and the pitch angle of the incoming wave directions of the direct wave and the scattered wave calculated by the super-resolution DOA estimation unit, the distance Doppler spectrum between the direct wave and the scattered wave output by the distance Doppler processing unit and the double-station RCS value of the measured wide-angle active scattering unit output by the double-station RCS calculation unit in real time;
the wireless communication unit is used for sending position and attitude control instructions to the unmanned aerial vehicle carrying platform and receiving position coordinate information downloaded by the unmanned aerial vehicle carrying platform in real time.
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| CN117538627B (en) * | 2024-01-08 | 2024-03-12 | 成都湖山电子科技有限公司 | Port impedance consistency measurement equipment and method |
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