A cross-band microwave target tracking and detection device and method

Abstract

The application belongs to the technical field of quantum precision measurement, and discloses a cross-frequency-band microwave target tracking and detecting device and method.The device comprises a light source assembly, an atomic array probe, an antenna assembly and a signal acquisition and processing assembly; the light source assembly is used for providing a plurality of detection pump light combinations to the atomic array probe; the antenna assembly comprises a Cassegrain antenna, a signal generator and an electronic power divider; the atomic array probe comprises a surface waveguide and a plurality of linearly arranged atomic gas chambers; the surface waveguide is arranged on the surface of each atomic gas chamber; and the signal acquisition and processing assembly is used for receiving detection light returned by each atomic gas chamber; the cross-waveband measurement of the plurality of atomic gas chambers expands the frequency band of the microwave target measurement, and has the advantages of high sensitivity, large frequency band range, high accuracy, all-around tracking and measurement, etc.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of quantum precision measurement, and particularly relates to a cross-frequency-band microwave target tracking and detecting device and method. BACKGROUND

[0002] The traditional classical wireless measurement system mainly relies on a superheterodyne receiver based on a metal antenna and an electronic circuit. After years of development, the measurement sensitivity has reached the limit and cannot be tracked in real time, and it is difficult to realize cross-frequency-band higher sensitivity measurement, such as high-precision measurement, space signal detection, and weak electric field signal sensing. The Rydberg microwave quantum sensor has a limit sensitivity limited by quantum noise, which is several orders of magnitude smaller than thermal noise, and can be used to realize ultra-high sensitivity measurement, provide an absolute standard for precise measurement science, and realize weak signal sensing, which greatly promotes the development of scientific research.

[0003] In addition, the current classical wireless measurement system is limited by the bandwidth of the classical microwave antenna, and the realization of cross-frequency-band microwave signal measurement requires carrying multiple aperture antennas matched with the wavelength of the measured microwave, which makes the measurement device more complex, and the measurement sensitivity has reached the upper limit. The wavelength of the cross-frequency-band microwave signal changes in position, and the antenna needs to be tracked in real time. Although the Rydberg microwave quantum sensor has high sensitivity, it is limited by the characteristics of atomic energy levels, and the measured microwave band range is single, which makes it difficult to realize cross-band microwave target measurement and tracking. Therefore, a cross-frequency-band microwave target tracking and detecting device needs to be designed to solve the above problems. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a cross-frequency-band microwave target tracking and detecting device and method to realize high sensitivity measurement of cross-frequency-band microwave targets.

[0005] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows: a cross-frequency-band microwave target tracking and detecting device, comprising: a light source assembly, an atomic array probe, an antenna assembly, and a signal acquisition and processing assembly;

[0006] The light source assembly is used to provide a plurality of detection pump light combinations to the atomic array probe; the detection pump light combination includes a detection light and a pump light, the detection light in each detection pump light combination has the same wavelength, and the pump light has different wavelengths, which are used to excite different Rydberg states of atoms;

[0007] The antenna assembly comprises a Cassegrain antenna, a signal generator, and an electronic power divider. The Cassegrain antenna is used to receive the microwave signal sent by the microwave target. The signal generator is used to generate a local oscillator microwave signal. The electronic power divider is used to combine and send the microwave signal sent by the microwave target and the local oscillator microwave signal to the atomic array probe.

[0008] The atomic array probe comprises a surface waveguide and a plurality of linearly arranged atomic cells, the surface waveguide is arranged on the surface of each atomic cell; a microwave transmission interface is arranged on the atomic cell at the head end, the microwave transmission interface is used for transmitting the microwave signal output by the electronic power divider into each atomic cell; each probe pump light combination output by the light source assembly corresponds to one atomic cell; a light guide device is arranged on each atomic cell, the light guide device is used for reversely incident corresponding probe pump light combination to the atomic cell along the microwave transmission direction, and is also used for making the probe light in the probe pump light combination return along the original path and be received by the signal acquisition and processing assembly;

[0009] The signal acquisition and processing assembly is used for receiving the probe light returned by each atomic cell, and realizing microwave measurement according to the probe light intensity.

[0010] The light source assembly comprises a probe laser, a pump laser, a first beam splitter, a second beam splitter, a plurality of AOMs, a plurality of dichroic mirrors and a plurality of PBS prisms, the probe light output by the probe laser is divided into a plurality of beams by the first beam splitter, each probe light is incident to a dichroic mirror, the pump light output by the pump laser is divided into a plurality of beams by the second beam splitter, each pump light is incident to a dichroic mirror after frequency shift by an AOM, the dichroic mirror is used for combining corresponding probe light and pump light to form a probe pump light combination and then sending the probe pump light combination to the PBS prism, and the PBS prism is used for transmitting the probe pump light combination to the corresponding atomic cell by an optical fiber.

[0011] The atomic cell has four, the pump light output by the pump laser is divided into four beams by the second beam splitter, the wavelengths of the pump light after passing through each AOM are 508.660 nm, 508.718 nm, 508.903 nm and 508.678 nm respectively, and the frequency of the probe light output by the probe laser is 852 nm.

[0012] The light guide device comprises a first optical fiber coupler, a right-angle reflection prism, a quarter-wave plate, a lens and a zero-degree mirror, the right-angle reflection prism is arranged at the end of the atomic cell, the probe pump light combination is transmitted to the first optical fiber coupler by an optical fiber, is reflected by the right-angle reflection prism after being output from the first optical fiber coupler, is incident to the atomic cell, then is incident to the zero-degree mirror after passing through the quarter-wave plate and the lens in the atomic cell, returns to the first optical fiber coupler along the original path after being reflected by the zero-degree mirror, the lens is used for focusing the light beam and coupling the light beam to the first optical fiber coupler, and the quarter-wave plate is used for changing the polarization of the probe light passing through twice by 90° and separating the probe light from the original incident light by the PBS prism.

[0013] The atomic array probe further comprises a protective cover and a partition plate, the protective cover is arranged outside each linearly arranged atomic cell for isolating external electromagnetic field interference, and the partition plate is arranged between each atomic cell for isolating optical path interference between the atomic cells.

[0014] The signal acquisition and processing assembly comprises an optical filter, a photodetector array, a signal acquisition card and a signal processor, the optical filter is used for filtering out pump light in the combined probe pump light returned from each atomic cell, the photodetector array is used for detecting probe light returned from each atomic cell, and the microwave target intensity is calculated by the signal processor after the detection signal is acquired by the signal acquisition card.

[0015] The Cassegrain antenna comprises a main reflector, a sub-reflector and a microwave collecting device arranged coaxially, and further comprises a scissor-type lifting platform, a rotating table, a supporting table, an extension rod, a rotating arm and a driving motor, the rotating table is arranged on the scissor-type lifting platform, the driving motor is fixed on the rotating table, one end of the rotating arm is connected with a rotating shaft of the driving motor, and the other end is fixedly connected with the supporting table; the main reflector, the sub-reflector and the microwave collecting device are arranged on the supporting table, and the microwave collecting device is arranged on the supporting table through the extension rod.

[0016] The main reflector comprises a plurality of central-symmetric antenna panels, and the antenna panels are connected with the supporting table through supporting rods and electric extension rods.

[0017] The cross-band microwave target tracking and detecting device further comprises a controller, an output end of the signal acquisition and processing assembly is connected with the controller, and the controller is connected with control ends of the scissor-type lifting platform, the rotating table, the driving motor, the extension rod and the electric extension rod, so as to adjust the scissor-type lifting platform, the rotating table, the driving motor, the extension rod and the electric extension rod according to the measurement result, and realize automatic tracking and sighting of the Cassegrain antenna.

[0018] The controller is further connected with the signal generator, so as to control the frequency and amplitude of the local microwave signal output by the signal generator according to the measurement result.

[0019] In addition, the application further provides a cross-band microwave target tracking and detecting method, which is realized according to the cross-band microwave target tracking and detecting device and comprises the following steps.

[0020] Step 1: turn on the light source assembly and the antenna assembly, measure the microwave target by the signal acquisition and processing assembly, and obtain preliminary information of the microwave target;

[0021] Step 2: adjust the frequency and amplitude of the local microwave signal of the output signal of the signal generator, so that the measured microwave signal intensity is maximum;

[0022] Step 3: adjust the opening angle of the main reflector by controlling the length of the electric telescopic rod, adjust the position of the microwave collecting device by controlling the length of the telescopic rod, adjust the pitch of the Cassegrain antenna by controlling the rotation angle of the rotating table and the driving motor, and adjust the height of the Cassegrain antenna by controlling the lifting of the scissor lifting table, until the measured microwave signal intensity is maximum.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] The present application provides a cross-band microwave target tracking and detection device and method, which detects the microwave signal through an atomic array probe comprising a plurality of atomic chambers, each of which is excited to different Rydberg states, so as to realize multi-band microwave measurement, so that the measurement frequency band can cover 1-20GHz; moreover, the evanescent field formed by the surface waveguide enhances the microwave electric field strength, further improving the measurement accuracy; in addition, the present application uses a Cassegrain antenna for measurement, which has a relatively compact antenna structure and is relatively easy to manufacture; the main reflector composed of a plurality of antenna panels has variable curvature; through the design of the antenna structure, the antenna inclination angle can be adjusted, and automatic tracking and sighting can be realized; in addition, the present application controls the microwave collecting device through the lifting telescopic rod, which can solve the problem of low collection efficiency caused by the change of the cross-band microwave signal convergence point, greatly improving the efficiency of the antenna receiving microwave signal; therefore, the present application has the advantages of high sensitivity, wide frequency band, high accuracy, and can track and measure in all directions. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 A cross-band microwave target tracking and detection device provided for the first embodiment of the present application;

[0026] Figure 2 A structure diagram of the atomic array probe detection in the first embodiment of the present application;

[0027] Figure 3 A structure diagram of the light source assembly in the first embodiment of the present application;

[0028] Figure 4 A structure diagram of the antenna assembly in the first embodiment of the present application;

[0029] Figure 5 A working flowchart of a cross-band microwave target tracking and detection device provided for the first embodiment of the present application;

[0030] Figure 6 A flowchart of a cross-band microwave target tracking and detection method provided for the second embodiment of the present application;

[0031] In the figure, 1-electronic power divider; 2-signal generator; 3-Cassegrain antenna; 4-controller; 5-light source assembly; 6-PBS prism; 7-photodetector array; 8-signal acquisition card; 9-signal processor; 10-display screen; 11-detection laser; 12-frequency stabilizer; 13-first beam splitter; 14-pump laser; 15-second beam splitter; 16-AOM; 17-dichroic mirror; 18-reflector; 19-atom array probe; 20-collimator; 21-second fiber coupler; 22-filter; 3-1-secondary reflector; 3-2-support column; 3-3-primary reflector; 3-4-antenna panel; 3-5-electric telescopic rod; 3-6-support rod; 3-7-microwave collecting device; 3-8-telescopic rod; 3-9-fixed platform; 3-10-support platform; 3-11-rotating arm; 3-12-drive motor; 3-13-rotating platform; 3-14-scissor lift platform; 19-1-protective cover; 19-2-first optical fiber coupler; 19-3-surface waveguide; 19-4-microwave transmission interface; 19-5-atomic gas chamber; 19-6-right-angle reflecting prism; 19-7-partition; 19-8-quarter-wave plate; 19-9-lens, 19-10-zero-degree reflector. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] like Figure 1 As shown, this embodiment provides a cross-band microwave target tracking and detection device, including: a light source component 5, an atomic array probe 19, an antenna component and a signal acquisition and processing component.

[0034] The light source assembly 5 is used to provide multiple detection pump light combinations to the atomic array probe; each detection pump light combination includes a beam of detection light and a beam of pump light. The detection light wavelengths in each detection pump light combination are the same, and the pump light wavelengths are different, which are used to excite different Rydberg states of atoms.

[0035] like Figure 1 As shown, the antenna assembly includes a Cassegrain antenna 3, a signal generator 2 and an electronic power divider 1. The Cassegrain antenna 3 is used to receive the microwave signal sent by the microwave target, the signal generator 2 is used to generate a local oscillator microwave signal, and the electronic power divider 1 is used to combine the microwave signal sent by the microwave target and the local oscillator microwave signal and send them to the atomic array probe.

[0036] like Figure 2 As shown, in this embodiment, the atomic array probe 19 includes a surface waveguide 19-3 and a plurality of linearly arranged atomic gas cells 19-5, wherein the atomic gas cells 19-5 are arranged on the surface waveguide 19-3; a microwave transmission interface 19-4 is provided on the atomic gas cell 19-5 at the head end, and the microwave transmission interface 19-4 is used to transmit the microwave signal output by the electronic power divider to each atomic gas cell 19-5; each detection pump light combination output by the light source component corresponds to an atomic gas cell 19-5; each atomic gas cell 19-5 is provided with a light guide device, which is used to reversely incident the corresponding detection pump light combination along the microwave emission direction to the atomic gas cell 19-5, and is also used to make the detection light in the detection pump light combination return along the original path and be received by the signal acquisition and processing component. Among them, the surface waveguide 19-3 has a microwave amplification effect, which can realize local microwave signal enhancement, increase the atomic sensing microwave signal intensity of the atomic gas cell 19-5, and further improve the measurement accuracy. In this embodiment, the signal to be measured is finally written into the detection light through the Cassegrain antenna, coaxial line, surface waveguide, and Rydberg atomic gas cell. The microwave transmission interface 19-4 is an SMA interface.

[0037] In this embodiment, the substrate layer of surface waveguide 19-3 is made of high-dielectric-constant aluminum oxide, and two coplanar, parallel metal plates are disposed on its surface. An evanescent field is formed between the metal plates, with a polarization direction parallel to the surface of surface waveguide 19-3. This evanescent field has a strong, locally enhanced electric field. The signal to be measured, received by the antenna, propagates between the metal plates, where it forms a standing wave field on the surface of surface waveguide 19-3, with multiple maxima and minima. When an atomic gas chamber 19-5, serving as an atomic sensing probe, is disposed on the surface of surface waveguide 19-3, it can be positioned at the location of maximum field distribution based on the distribution of the standing wave field formed on surface waveguide 19-3 at the measured frequency.

[0038] In this embodiment, the signal acquisition and processing component is used to receive the detection light returned by each atomic gas chamber 9-4 and implement microwave measurement according to the intensity of the detection light.

[0039] Furthermore, if Figure 3As shown, in the embodiment, the light source assembly includes a probe laser 11, a pump laser 14, a first beam splitter 13, a second beam splitter 15, a plurality of AOMs 16, a plurality of dichroic mirrors 17, a plurality of PBS prisms 6, the probe light output by the probe laser 11 is split into multiple beams by the first beam splitter, each beam of probe light is incident on a dichroic mirror 17 after a mirror 18, the pump light output by the pump laser 1 is split into multiple beams by the second beam splitter 5, each beam of pump light is incident on a dichroic mirror 17 after frequency shifting by an AOM 6, the dichroic mirror 17 is used to combine the corresponding probe light and pump light to form a probe-pump light combination and then send it to the PBS prism 6, and the PBS prism 6 is used to send the probe-pump light combination to the corresponding atomic cell 19-5 through an optical fiber.

[0040] Further, as shown, Figure 3 The light source assembly further includes a collimator 20 and a second fiber coupler 21, wherein the probe light and the coupling light are sequentially sent to the atomic cell 19-5 through an optical fiber after passing through the PBS prism 6, the collimator 20 and the second fiber coupler 21.

[0041] In addition, the light source assembly further includes a frequency stabilizer 12 for stabilizing the laser of the probe laser 11.

[0042] Specifically, in the embodiment, the atomic cell 19-5 is a cesium atomic glass vapor cell. Then the wavelength of the probe laser is 852 nm, and the wavelength of the pump laser is 510 nm.

[0043] Specifically, in the embodiment, the frequency points 1.2 GHz, 1.5 GHz, 2.5 GHz and 12 GHz are used as adjacent Rydberg energy level transition channels, then the atomic cell 19-5 has four, the pump light output by the pump laser is split into four beams by the second beam splitter, and the wavelengths of the pump light after passing through each AOM are 508.660 nm, 508.718 nm, 508.903 nm and 508.678 nm, respectively. By using the resonance excitation method to lock the corresponding Rydberg state, the transition channels of 89D 3 / 2 -90P 1 / 2 , 83D 3 / 2 -84P 1 / 2 , 70D 3 / 2 -71P 1 / 2 and 87D 3 / 2 -87P 3 / 2 , the EIT-AT splitting spectrum and the atomic heterodyne signal are recorded by the signal acquisition and processing assembly, and the microwave measurement of the corresponding frequency point can be realized. The frequency of the probe light output by the probe laser is 852 nm. Then the different Rydberg states in each atomic cell 19-5 couple different bands of microwaves, which can realize the cross-band detection of the target microwave in the frequency range of 1-20 GHz.

[0044] Specifically, in the embodiment, the probe laser 11 is a semiconductor laser of Toptica SHG Pro produced by Toptica, and the pump laser 14 is an external cavity semiconductor laser of Toptica SHG Pro produced by Toptica; the signal generator 2 is N5183B produced by Keysight; the photodetector array 7 is DET-10A produced by Thorlabs; and the signal acquisition card 8 is PCI-6733.

[0045] Further, as shown in Figure 2 the embodiment, the light guide device comprises a first fiber coupler 19-2, a right-angle reflection prism 19-6, a quarter-wave plate 19-8, a lens 19-9, and a zero-degree mirror 19-10. The right-angle reflection prism 19-6 is arranged at the end of the atomic gas chamber 19-5. The combined probe pump light is transmitted to the first fiber coupler 19-2 through an optical fiber, is reflected by the right-angle reflection prism 19-6 after being output from the first fiber coupler 19-2, is incident on the atomic gas chamber 19-5, and then is incident on the zero-degree mirror 19-10 after passing through the quarter-wave plate 19-8 and the lens 19-9 in the atomic gas chamber 19-5. The light is reflected by the zero-degree mirror 19-10 and returns to the first fiber coupler 19-2 along the original path. The lens 19-9 is used to focus the light beam and couple it to the first fiber coupler 19-2. The quarter-wave plate 19-8 is used to change the polarization of the probe light passing through twice by 90°, so that the probe light is separated from the incident light by the PBS prism 6. In the embodiment, since the returned 852 nm probe laser passes through the quarter-wave plate 19-8 twice, the polarization direction of the 852 nm laser returned to the PBS prism 6 is perpendicular to that of the incident light, so that the incident light and the returned reflected light are separated at the PBS prism 6. Then, the returned light corresponding to each atomic gas chamber is filtered by the optical filter 22 to remove the coupled light, and the probe light is subsequently received and processed by the signal acquisition and processing assembly.

[0046] Specifically, in the embodiment, the zero-degree mirror 19-10 can be a high-reflection film arranged on the inner surface of the atomic gas chamber 19-5.

[0047] Further, as shown in Figure 2 the embodiment, the atomic array probe further comprises a protective cover 19-1 and a partition plate 19-7. The protective cover is arranged outside each linearly arranged atomic gas chamber 19-5 and is used to isolate external electromagnetic field interference. The partition plate 19-7 is arranged between each atomic gas chamber 19-5 and is used to isolate the optical path interference between the atomic gas chambers 19-5.

[0048] Specifically, in the embodiment, asFigure 1 As shown, the signal acquisition and processing assembly comprises an optical filter 22, a photodetector array 7, a signal acquisition card 8 and a signal processor 9. After the reflected light returning to the PBS prism 6 is filtered of the pump light by the optical filter 22, the probe light is received by the photodetector array 7, and the optical signal is further converted into an electrical signal and collected and processed by the signal acquisition card 8 and the signal processor 9. The optical filter 22 is used to filter the pump light in the combined probe-pump light returning from each atomic cell 19-5, and the photodetector array 7 is used to detect the probe light returning from each atomic cell 19-5. After the detection signal is collected by the signal acquisition card 8, the microwave target intensity is calculated by the signal processor 9.

[0049] In addition, in this embodiment, the signal acquisition and processing assembly further comprises a display screen 10 connected to the signal processor 9 for displaying the measurement results.

[0050] Further, in this embodiment, since the cross-band microwave signal converges by the Cassegrain antenna and the position changes with the wavelength of the microwave, the Cassegrain antenna has a tracking function. Specifically, as shown in Figure 4 The Cassegrain antenna 3 comprises a primary reflector 3-3, a secondary reflector 3-1 and a microwave collecting device 3-7 arranged coaxially, and further comprises a scissor-type lifting platform 3-14, a rotating platform 3-13, a support platform 3-10, an extension rod 3-8, a rotating arm 3-11 and a driving motor 3-12. The rotating platform 3-13 is arranged on the scissor-type lifting platform 3-14, the driving motor 3-12 is fixed on the rotating platform 3-13, one end of the rotating arm 3-11 is connected with the rotating shaft of the driving motor 3-12, and the other end is fixedly connected with the support platform 3-10. The primary reflector 3-3, the secondary reflector 3-1 and the microwave collecting device 3-7 are arranged on the support platform 3-10, and the microwave collecting device 3-7 is arranged on the support platform 3-10 through the extension rod 3-8. The height of the Cassegrain antenna can be adjusted by the scissor-type lifting platform 3-14, the inclination of the Cassegrain antenna in the direction of the motor rotating shaft can be adjusted by driving the rotating arm by the driving motor 3-12, and the two-dimensional pitch angle of the entire Cassegrain antenna can be adjusted by the rotation of the rotating platform 3-13.

[0051] Further, in this embodiment, the primary reflector 3-3 comprises a plurality of centrally symmetric antenna panels 3-4. Each antenna panel 3-4 is fan-shaped and arranged centrally symmetrically to form the primary reflector 3-3. The antenna panel 3-4 is connected with the support platform 3-10 through a support rod 3-6 and an electrically operated extension rod 3-5. By controlling the length of the electrically operated extension rod 3-5, a slight change in the opening angle of the primary reflector 3-3 can be realized, and thus more accurate reception of the microwave signal can be achieved.

[0052] Further, if Figure 1 As shown, a cross-band microwave target tracking and detection device in this embodiment also includes a controller 4. The output end of the signal acquisition and processing component is connected to the controller 4. The controller 4 is connected to the control ends of the scissor lift platform 3-14, rotating platform 3-13, drive motor 3-12, telescopic rod 3-8, and electric telescopic rod 3-5. The controller is used to adjust the scissor lift platform 3-14, rotating platform 3-13, drive motor 3-12, telescopic rod 3-8, and electric telescopic rod 3-5 based on the measurement results to achieve automatic tracking and aiming of the Cassegrain antenna. In addition, the controller is also connected to the signal generator 2 to control the frequency and amplitude of the local oscillator microwave signal output by the signal generator 2 based on the measurement results.

[0053] Furthermore, in this embodiment, the controller 4 is also used to control the laser Rabi frequency output by the light source assembly. By controlling parameters such as the laser Rabi frequency, the local oscillator microwave electric field frequency, and the amplitude, the measurement signal is continuously optimized, and the atoms are adjusted to a Rydberg state that is more suitable for measurement, thereby achieving more accurate measurements across all frequency bands.

[0054] The output end of the signal acquisition and processing component is connected to the control end of the scissor lift platform 3-14, the rotating platform 3-13, the drive motor 3-12, the telescopic rod 3-8 and the electric telescopic rod 3-5, and is used to adjust the scissor lift platform 3-14, the rotating platform 3-13, the drive motor 3-12, the telescopic rod 3-8 and the electric telescopic rod 3-5 according to the measurement results to achieve automatic tracking and aiming of the Cassegrain antenna.

[0055] Specifically, by controlling the length of the electric telescopic rod, the opening angle of the main reflector 3-3 can be adjusted to better receive microwave targets. In addition, by controlling the length of the telescopic rod 3-8, the position of the microwave collecting device 3-7 can be adjusted to adapt to the changes in the convergence point of the Cassegrain antenna caused by the microwave wavelength. By controlling the rotation angle of the rotating table 3-13 and the driving motor 3-12, the pitch of the Cassegrain antenna can be adjusted. By controlling the lifting and lowering of the scissor lift table 3-14, the height of the Cassegrain antenna can be adjusted, ultimately achieving tracking and reception of microwave targets.

[0056] Compared with the traditional classical parabolic antenna, the Cassegrain antenna combining the main reflector 3-3, the antenna panel 3-4, the sub-reflector 3-1 and the microwave collecting device 3-7 is adopted in the embodiment, which makes the structure of the antenna more compact and is more convenient to manufacture. In the Cassegrain antenna, the main reflector 3-3 is a rotating paraboloid, and the sub-reflector 3-1 is a rotating hyperboloid. In the structure, one focus of the hyperboloid coincides with the focus of the paraboloid, and the focal axis of the hyperboloid coincides with the focal axis of the paraboloid. When the signal emitted by the microwave source is radiated to the main reflector paraboloid, the signal is converged to the virtual focus of the sub-reflector through the primary reflection, and is converged to the focus of the paraboloid after the secondary reflection of the hyperboloid of the sub-reflector 3-1, which is equivalent to the ray directly emitted from the virtual focus of the hyperboloid. Therefore, as long as the focus of the hyperboloid coincides with the focus of the paraboloid, the ray reflected by the main reflector to the sub-reflector can be converged to the focus by the hyperboloid, and then the ray is collected by the microwave collecting device 3-7 and coupled to the microwave transmission interface 19-4 of the atomic cell through the electronic power divider.

[0057] The atomic array probe in the embodiment includes a plurality of atomic cells and a plurality of groups of measurement light paths, and constitutes a microwave array probe. The plurality of atomic cells are used for cooperative measurement. The measurement principle is the AC Stark effect of far detuning. When the frequency of the electromagnetic field to be measured changes in a very large range, the frequency shift caused by the AC Stark effect shows obvious resonance peaks and far detuning corresponding characteristics. Overall, the resonance has the largest energy level frequency shift, thereby having more sensitive measurement sensitivity. The frequency shift caused by the electromagnetic field is obviously reduced relative to the resonance due to the gradually weakened interaction strength, and in the measurement range of 1-20 GHz, the response of the far detuning is only reduced by about 10 dB than the position of the resonance, which is much better than the classical measurement system. Moreover, the measurement device of the embodiment optimizes the power and frequency of the local oscillator field according to the measurement result, which can improve the weakening of the signal caused by the far detuning relative to the resonance to a certain extent, and improve the measurement sensitivity.

[0058] In the embodiment, the microwave electric field interacts with the atom to cause the energy level of the Rydberg atom to be shifted, and the amount of the frequency shift is proportional to the intensity of the microwave electric field. The energy level frequency shift of the Rydberg atom can be read out by the full-optical electromagnetic induced transparency (EIT) spectrum, and finally the information of the microwave is reflected in the change of the absorption of the probe laser. The change of the absorption of the probe laser is converted into an electric signal by the photodetector, and the electric signal can be collected and processed by using a classical acquisition card to extract the information of the electromagnetic field signal to be measured.

[0059] As Figure 5The figure shows the working principle of this embodiment. The main reflector 3-3 of the Cassegrain antenna collects microwave source signals from any direction through the interaction of various antenna panels 3-4. The sub-reflector 3-1 collects and transmits the signals to the microwave collection device 3-7, which transmits them via a coaxial cable to the microwave transmission SMA interface 19-4 and inputs them into the atomic gas chamber 19-5. The surface waveguide 19-3 on the surface of the atomic gas chamber 19-5 forms an evanescent field. The evanescent field has a strong local enhanced electric field, which can achieve a certain degree of enhancement of the antenna collection signal. In addition, the antenna assembly can scan the direction of the antenna unit to achieve target tracking and aiming. The atomic gas cells 19-5 are evenly placed on the surface waveguide 19-3. The 510nm pump light wavelengths in each detection pump light combination output by the light source component are different, which can excite the atoms in the corresponding atomic gas cells 19-5 to different Rydberg states, and then measure the electric field of the surface through multiple atoms in different Rydberg states; different Rydberg states couple microwaves of different bands to achieve cross-band detection of target microwaves in the frequency range of 1-20GHz.

[0060] During signal processing, the signal acquisition and processing component can measure and obtain preliminary phase, amplitude, and frequency information; the controller then determines whether the obtained signal is accurate, and optimizes the local oscillator microwave electric field frequency, amplitude and other parameters based on the amplitude and frequency information in the measurement information; in addition, the pump laser frequency can be optimized through feedback from the measurement information and adjusted to a Rydberg state suitable for measurement, ultimately achieving all-round high-sensitivity measurement.

[0061] Since the intensity change of the 852nm laser transmitted to the photodetector array 20 is affected by factors such as the amplitude, phase, frequency, polarization, and incident angle of the microwave signal, the atomic probe unit acts as a sensor for the microwave signal. The low-frequency electrical signal output by its photodetector array 18 can represent the modulation information of the microwave signal. Through the electrical signal SMA interface, the low-frequency electrical signal is transmitted to the signal processing part for information collection and analysis. After the collection is completed, it is processed by the signal processor 9 and the measurement result is output on the display screen 10. At this time, analysis and judgment are performed. If the measurement result is correct, the goal is achieved and high-sensitivity cross-band measurement is achieved. If the measurement result is incorrect, the result is fed back to the antenna control part through the connection between the signal processor 9 and the controller 4 for re-measurement. This process is repeated until an accurate measurement result is obtained.

[0062] Example 2

[0063] like Figure 6 As shown, the second embodiment of the present invention provides a cross-band microwave target tracking and detection method, which is implemented based on the cross-band microwave target tracking and detection device described in the first embodiment, and includes the following steps:

[0064] Step 1: turn on the light source assembly and the antenna assembly, measure the microwave target through the signal acquisition and processing assembly, and obtain the preliminary information of the microwave target;

[0065] Step 2: adjust the frequency and amplitude of the local oscillator microwave signal of the signal generator output signal to maximize the measured microwave signal intensity;

[0066] Step 3: adjust the opening angle of the main reflector 3-3 by controlling the length of the electric telescopic rod, adjust the position of the microwave collection device 3-7 by controlling the length of the telescopic rod 3-8, adjust the pitch of the Cassegrain antenna by controlling the rotation angle of the rotary table 3-13 and the driving motor 3-12, and adjust the height of the Cassegrain antenna by controlling the lifting of the scissor lifting platform 3-14, until the measured microwave signal intensity is maximized.

[0067] In summary, the present application provides a cross-band microwave target tracking and detection device and method, which detects microwave signals through an atomic array probe comprising a plurality of atomic chambers, each atomic chamber is excited to different Rydberg states, which can realize multi-band microwave measurement, and the evanescent field formed by the surface waveguide enhances the microwave electric field strength, further improving the measurement accuracy. In addition, the present application uses a Cassegrain antenna for measurement, the antenna structure is relatively compact and the manufacturing is relatively convenient; the main reflector composed of a plurality of antenna panels has variable curvature; by designing the antenna structure, the antenna inclination angle can be adjusted and automatic tracking and sighting can be realized. In addition, the present application controls the microwave collection device through the telescopic rod, which can solve the problem of low collection efficiency caused by the change of the cross-band microwave signal convergence point, greatly improving the efficiency of the antenna receiving microwave signals. Therefore, the present application has the advantages of high sensitivity, cross-band, accuracy, and high all-around tracking measurement.

[0068] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A cross-band microwave target tracking and detection device, characterized in that: include: Light source assembly, atomic array probe, antenna assembly and signal acquisition and processing assembly; The light source assembly is used to provide a plurality of detection pump light combinations to the atomic array probe; the detection pump light combinations include a beam of detection light and a beam of pump light, the detection light wavelengths in each detection pump light combination are the same, and the pump light wavelengths are different, which are used to excite different Rydberg states of atoms; The antenna assembly includes a Cassegrain antenna, a signal generator, and an electronic power splitter. The Cassegrain antenna is used to receive microwave signals sent by a microwave target. The signal generator is used to generate a local oscillator microwave signal. The electronic power splitter is used to combine the microwave signal sent by the microwave target and the local oscillator microwave signal and then send the combined signal to the atomic array probe. The atomic array probe comprises a surface waveguide (19-3) and a plurality of linearly arranged atomic gas chambers (19-5), wherein the surface waveguide (19-3) is arranged on the surface of each of the atomic gas chambers (19-5); a microwave transmission interface (19-4) is arranged on the atomic gas chamber (19-5) at the head end, and the microwave transmission interface (19-4) is used to transmit the microwave signal output by the electronic power divider into each of the atomic gas chambers (19-5); each detection pump light combination output by the light source component corresponds to an atomic gas chamber (19-5); each of the atomic gas chambers (19-5) is respectively provided with a light guide device, and the light guide device is used to reversely incident the corresponding detection pump light combination along the microwave emission direction into the atomic gas chamber (19-5), and is also used to make the detection light in the detection pump light combination return along the original path and be received by the signal acquisition and processing component; The signal acquisition and processing component is used to receive the detection light returned by each atomic gas chamber (19-5) and realize microwave measurement according to the intensity of the detection light.

2. The cross-band microwave target tracking and detection device according to claim 1, characterized in that: The light source assembly includes a detection laser, a pump laser, a first beam splitter, a second beam splitter, multiple AOMs, multiple dichroic mirrors, and multiple PBS prisms. The detection light output by the detection laser is divided into multiple beams by the first beam splitter, and each beam of detection light is incident on a dichroic mirror. The pump light output by the pump laser is divided into multiple beams by the second beam splitter, and each beam of pump light is frequency-shifted by an AOM and then incident on a dichroic mirror. The dichroic mirror is used to combine the corresponding detection light and pump light to form a detection pump light combination and then send it to the PBS prism. The PBS prism is used to send the detection pump light combination to the corresponding atomic gas chamber (19-5) via optical fiber.

3. The cross-band microwave target tracking and detection device according to claim 2, characterized in that: There are four atomic gas chambers (19-5), and the pump light output by the pump laser is divided into four beams by the second beam splitter. The wavelengths of the pump light after passing through each AOM are 508.660nm, 508.718nm, 508.903nm and 508.678nm respectively. The frequency of the detection light output by the detection laser is 852nm.

4. The cross-band microwave target tracking and detection device according to claim 2, characterized in that: The light guide device comprises: a first optical fiber coupler (19-2), a right-angle reflection prism (19-6), a quarter-wave plate (19-8), a lens (19-9) and a zero-degree reflection mirror (19-10); the right-angle reflection prism (19-6) is arranged at the end of the atomic gas chamber (19-5); the detection pump light combination is transmitted to the first optical fiber coupler (19-2) via the optical fiber, and is output from the first optical fiber coupler (19-2) and reflected by the right-angle reflection prism (19-6) to enter the atomic gas chamber (19-5), and then After passing through a quarter-wave plate (19-8) and a lens (19-9) in an atomic gas chamber (19-5), the light is incident on a zero-degree reflector (19-10), and after being reflected by the zero-degree reflector (19-10), it returns to the first optical fiber coupler (19-2) along the original path. The lens (19-9) is used to focus the light beam so that it is coupled to the first optical fiber coupler (19-2). The quarter-wave plate (19-8) is used to change the polarization of the twice-passed detection light by 90° and then separate it from the original incident light through the PBS prism.

5. The cross-band microwave target tracking and detection device according to claim 1, characterized in that: The atomic array probe further comprises a protective cover (19-1) and a partition (19-7). The protective cover is arranged outside each linearly arranged atomic gas chamber (19-5) for isolating external electromagnetic field interference. The partition (19-7) is arranged between each atomic gas chamber (19-5) for isolating optical path interference between each atomic gas chamber (19-5).

6. The cross-band microwave target tracking and detection device according to claim 1, characterized in that: The signal acquisition and processing component comprises a filter (22), a photodetector array, a signal acquisition card and a signal processor. The filter (22) is used to filter out the pump light in the detection pump light combination returned from each atomic gas chamber (19-5). The photodetector array is used to detect the detection light returned from each atomic gas chamber (19-5). After the detection signal is collected by the signal acquisition card, the microwave target intensity is calculated by the signal processor.

7. The cross-band microwave target tracking and detection device according to claim 1, characterized in that: The Cassegrain antenna comprises a coaxially arranged main reflector (3-3), a sub-reflector (3-1) and a microwave collecting device (3-7), and further comprises a scissor-type lifting platform (3-14), a rotating platform (3-13), a support platform (3-10), a telescopic rod (3-8), a rotating arm (3-11) and a driving motor (3-12), wherein the rotating platform (3-13) is arranged on the scissor-type lifting platform (3-14), the driving motor (3-12) is fixed on the rotating platform (3-13), one end of the rotating arm (3-11) is connected to the rotating shaft of the driving motor (3-12), and the other end is fixedly connected to the supporting platform (3-10); the main reflector (3-3), the sub-reflector (3-1) and the microwave collecting device (3-7) are arranged on the supporting platform (3-10), and the microwave collecting device (3-7) is arranged on the supporting platform (3-10) via the telescopic rod (3-8).

8. The cross-band microwave target tracking and detection device according to claim 7, characterized in that: The main reflector (3-3) comprises a plurality of centrosymmetrical antenna panels (3-4), and the antenna panels (3-4) are connected to the support platform (3-10) via a support rod (3-6) and an electric telescopic rod (3-5).

9. The cross-band microwave target tracking and detection device according to claim 8, characterized in that: The invention also includes a controller (4), wherein the output end of the signal acquisition and processing component is connected to the controller (4), and the controller (4) is connected to the control ends of the scissor lift platform (3-14), the rotating platform (3-13), the drive motor (3-12), the telescopic rod (3-8), and the electric telescopic rod (3-5), and is used to adjust the scissor lift platform (3-14), the rotating platform (3-13), the drive motor (3-12), the telescopic rod (3-8), and the electric telescopic rod (3-5) according to the measurement results to realize automatic tracking and aiming of the Cassegrain antenna; The controller (4) is also connected to the signal generator (2) and is used to control the frequency and amplitude of the local oscillator microwave signal output by the signal generator (2) according to the measurement result.

10. A cross-band microwave target tracking and detection method, implemented by a cross-band microwave target tracking and detection device according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Turn on the light source component and antenna component, measure the microwave target through the signal acquisition and processing component, and obtain preliminary information about the microwave target; Step 2: Adjust the frequency and amplitude of the local oscillator microwave signal output by the signal generator to maximize the measured microwave signal intensity; Step 3: Adjust the opening angle of the main reflector (3-3) by controlling the length of the electric telescopic rod, adjust the position of the microwave collecting device (3-7) by controlling the length of the telescopic rod (3-8), adjust the pitch of the Cassegrain antenna by controlling the rotation angle of the rotating table (3-13) and the driving motor (3-12), and adjust the height of the Cassegrain antenna by controlling the raising and lowering of the scissor lift table (3-14) until the measured microwave signal intensity is maximum.

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