CN112615155B - Microwave antennas and radars based on Rydberg atoms - Google Patents

Abstract

The present invention relates to a microwave antenna and radar based on Rydberg atoms. The atomic microwave antenna outputs an original reflection signal according to the reflection wave received from the space scanning electromagnetic wave. The signal processing device performs signal conversion processing on the original reflection signal to obtain a transformed reflection signal, and sends the transformed reflection signal to the radar signal processing device to instruct the radar signal processing device to display the radar signal according to the transformed reflection signal. Based on this, through the characteristics of Rydberg atoms such as high detection sensitivity, small response bandwidth to microwaves, and wide frequency domain, the radar antenna is endowed with advantages such as improved detection distance, anti-interference ability, convenience of frequency switching, and miniaturization. At the same time, through the signal conversion processing of the signal processing device, the signal accuracy based on Rydberg atom detection is improved.

Description

Microwave antennas and radars based on Rydberg atoms

Technical Field

The present invention relates to the field of antenna technology, and in particular to a microwave antenna and radar based on Rydberg atoms.

Background Art

Microwaves are radio waves with very short wavelengths, and microwaves have good directionality and their speed is equal to the speed of light. Using the working characteristics of microwaves, microwave radars, which are mainly used for distance and speed measurement, came into being. Existing microwave radars are based on the electromagnetic wave emission and reception technology of electric dipole antennas. Structurally, microwave radars require four processes to complete a detection: emission of electromagnetic waves, reception of electromagnetic waves reflected by the object to be measured, noise reduction filtering process, and back-end image reconstruction. Among them, the reflection and reception of electromagnetic waves are based on the electric dipole antenna array. The detection distance and detection sensitivity of the measured object are one of the core indicators for measuring radar. Traditional microwave radars are limited by the measurement sensitivity of electric dipole antennas to radio frequency electromagnetic fields, and their detection efficiency is greatly limited. For example, when an aircraft's airborne radar is conducting an air search, it can usually detect an opposing aircraft 150KM away. However, if the aircraft being searched is a new stealth aircraft, its radar reflection cross-section is only one percent to one thousandth of the usual one, and the airborne radar can only detect the stealth aircraft at a distance of about 10KM, which is even less than the visual distance.

In 2012, the Shaffer research group at the University of Oklahoma in the United States and the Pfau research group at the University of Stuttgart in Germany cooperated to use Rydberg hot atoms EIT (Electromagnetically Induced Transparency) and AT (Autler-Townes) splitting for the first time to convert the measurement of microwave electric field intensity into optical frequency measurement, and the measured microwave electric field sensitivity reached 30μVcm ^-1 Hz ^-1/2 . This provides the feasibility of realizing microwave antennas and even microwave radars based on the principle of atomic detection of electric fields.

Summary of the invention

Based on this, it is necessary to provide a microwave antenna and radar based on Rydberg atoms by adding other auxiliary equipment due to the response characteristics of Rydberg thermal atoms to electromagnetic waves.

A microwave antenna based on Rydberg atoms, comprising:

An atomic microwave antenna including a Rydberg atomic gas chamber is used to receive reflected waves of the space scanning electromagnetic waves and output an original reflected signal according to the reflected waves;

The signal processing device is used to perform signal conversion processing on the original reflection signal to obtain a transformed reflection signal, and send the transformed reflection signal to the radar signal processing device to instruct the radar signal processing device to display the radar signal according to the transformed reflection signal.

The above-mentioned microwave antenna based on Rydberg atoms, the atomic microwave antenna outputs the original reflection signal according to the reflected wave received from the space scanning electromagnetic wave, the signal processing device performs signal conversion processing on the original reflection signal, obtains the transformed reflection signal, and sends the transformed reflection signal to the radar signal processing device to instruct the radar signal processing device to display the radar signal according to the transformed reflection signal. Based on this, through the characteristics of Rydberg atoms such as high detection sensitivity, small response bandwidth to microwaves, and wide frequency domain, the radar antenna is endowed with advantages such as improved detection distance, anti-interference ability, convenience of frequency switching, and miniaturization. At the same time, the signal accuracy based on Rydberg atom detection is improved through the signal conversion processing of the signal processing device.

In one embodiment, an atomic microwave antenna includes a Rydberg atomic gas cell, a detection laser, a coupling laser, and a photodetector;

Rydberg hot atoms are stored in the Rydberg atomic gas chamber;

The detection laser is used to emit detection light, and the coupling laser is used to emit coupling light, wherein the detection light and the coupling light are used to excite the Rydberg hot atoms from the ground state to the Rydberg state, and the detection light is also used to generate the quantum interference effect of Raman absorption;

The photodetector is used to detect the splitting width of the Raman absorption peak and calculate the electric field strength to be measured to obtain the original reflection signal.

In one embodiment, the coupling light is blue detuned coupling light, and the detection light is red detuned detection light;

Among them, the detuning frequency of the blue detuned coupling light is 70 to 130 MHz; the detuning frequency of the red detuned detection light is 70 to 130 MHz.

In one embodiment, the frequency of the blue detuned coupling light is 100 MHz, and the central wavelength is 480 nm; the frequency of the red detuned detection light is 100 MHz, and the central wavelength is 780 nm.

In one embodiment, the Rydberg hot atoms are rubidium atoms.

In one embodiment, the process of performing signal transformation processing on the original reflection signal to obtain the transformed reflection signal includes the steps of:

Acquire first near-field data of the original reflected signal;

Performing mathematical transformation on the first near-field data to obtain far-field data of the original reflection signal;

Performing an inverse transformation of the mathematical transformation on the far-field data to obtain the second near-field data of the original reflected signal;

The transformed reflection signal is restored according to the second near-field data.

In one embodiment, the process of obtaining first near-field data of an original reflected signal comprises the steps of:

Perform preset sampling on the original reflected signal to obtain field distribution data of the preset sampling point;

First near-field data is determined based on the field distribution data.

In one embodiment, the mathematical transformation process is a fast Fourier transform process.

A microwave radar based on a Rydberg atomic antenna, comprising:

A microwave transmitting antenna array for transmitting space scanning electromagnetic waves;

A microwave antenna based on Rydberg atoms as in any of the above embodiments;

A radar signal processing device for displaying a radar signal based on a transformed reflection signal of a microwave antenna based on Rydberg atoms.

In the above-mentioned microwave radar based on the Rydberg atomic antenna, the atomic microwave antenna outputs the original reflection signal according to the reflected wave received from the space scanning electromagnetic wave, and the signal processing device performs signal conversion processing on the original reflection signal to obtain the transformed reflection signal, and sends the transformed reflection signal to the radar signal processing device to instruct the radar signal processing device to display the radar signal according to the transformed reflection signal. Based on this, through the characteristics of Rydberg atoms such as high detection sensitivity, small response bandwidth to microwaves, and wide frequency domain, the radar antenna is endowed with advantages such as improved detection distance, anti-interference ability, convenience of frequency switching, and miniaturization. At the same time, the signal accuracy based on Rydberg atom detection is improved through the signal conversion processing of the signal processing device.

In one embodiment, the microwave transmitting antenna array is used to transmit space scanning electromagnetic waves with a frequency of 1 GHz to 500 GHz.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a microwave antenna structure based on Rydberg atoms according to an embodiment;

FIG2 is a schematic diagram of the structure of a microwave antenna based on Rydberg atoms according to another embodiment;

3 is a flow chart of a signal conversion processing method of a signal processing device according to one embodiment;

FIG4 is a flow chart of a signal conversion processing method of a signal processing device according to another embodiment;

FIG5 is a structural diagram of a microwave radar module based on a Rydberg atomic antenna according to an embodiment;

FIG6 is a structural diagram of a microwave radar module based on a Rydberg atomic antenna according to another embodiment.

DETAILED DESCRIPTION

In order to better understand the purpose, technical solution and technical effect of the present invention, the present invention is further explained below in conjunction with the accompanying drawings and embodiments. At the same time, it is stated that the embodiments described below are only used to explain the present invention and are not used to limit the present invention.

An embodiment of the present invention provides a microwave antenna based on Rydberg atoms.

FIG1 is a schematic diagram of the structure of a microwave antenna based on Rydberg atoms according to an embodiment. As shown in FIG1 , a microwave antenna based on Rydberg atoms according to an embodiment includes a module 100 and a module 101:

An atomic microwave antenna 100 including a Rydberg atomic gas cell 200 is used to receive reflected waves of space scanning electromagnetic waves and output original reflected signals according to the reflected waves;

The signal processing device 101 is used to perform signal transformation processing on the original reflection signal to obtain a transformed reflection signal, and send the transformed reflection signal to the radar signal processing device to instruct the radar signal processing device to display the radar signal according to the transformed reflection signal.

The atomic microwave antenna 100 includes a Rydberg atomic gas chamber 200, and Rydberg atoms are stored in the Rydberg atomic gas chamber 200. In one embodiment, the Rydberg atoms include rubidium atoms or cesium atoms. As a preferred embodiment, the Rydberg atoms are rubidium atoms.

The atomic microwave antenna 100 collects the original reflected signal based on the excitation of the Rydberg atoms in the Rydberg atomic gas cell 200 from the ground state to the excited state.

In one embodiment, FIG2 is a schematic diagram of a microwave antenna structure based on Rydberg atoms in another embodiment. As shown in FIG2 , the atomic microwave antenna 100 includes a Rydberg atom gas chamber 200 , a detection laser 201 , a coupling laser 202 and a photodetector 203 ;

Rydberg hot atoms are stored in the Rydberg atomic gas chamber 202;

The detection laser 201 is used to emit detection light, and the coupling laser 202 is used to emit coupling light, wherein the detection light and the coupling light are used to excite the Rydberg cold atoms from the ground state to the Rydberg state, and the detection light is also used to generate the quantum interference effect of Raman absorption;

The photodetector 203 is used to detect the splitting width of the test Raman absorption peak, calculate the electric field strength to be measured, and obtain the original reflection signal.

As shown in Figure 2, the atomic microwave antenna utilizes the EIT effect of Rydberg atoms and measures the microwave electric field intensity based on the Raman absorption of cold Rydberg atoms. It converts the measurement of microwave electric field intensity into the measurement of Raman absorption peak splitting width to determine the original reflection signal.

Among them, the initial state of the Rydberg atoms in the vacuum system of the Rydberg atomic gas chamber is prepared in the ground state through optical pumping, and the cold atoms are excited from the ground state to the Rydberg state by blue detuned coupling light and red detuned detection light, and the quantum interference effect of Raman absorption is generated by red detuned detection light. Furthermore, the ground state and the Rydberg state are used as the two internal states of Raman absorption, and microwaves are used to realize the operations required for the Raman absorption peak. At this time, the microwave electric field to be measured interacts with the quantum state in Raman absorption. By detecting the splitting width of the Raman absorption peak, the electric field strength to be measured is obtained to determine the original reflection signal.

In one embodiment, the coupling light is blue detuned coupling light, and the detection light is red detuned detection light;

Among them, the detuning frequency of the blue detuned coupling light is 70 to 130 MHz; the detuning frequency of the red detuned detection light is 70 to 130 MHz.

As a preferred implementation, the detuning frequency of the blue detuned coupling light is 100 MHz, and the central wavelength is 480 nm; the detuning frequency of the red detuned detection light is 100 MHz, and the central wavelength is 780 nm.

The signal processing device 101 transforms the original reflected signal to eliminate the signal acquisition error of the atomic microwave antenna and improve the accuracy of the original reflected signal.

In one of the embodiments, FIG. 3 is a flow chart of a signal conversion processing method of a signal processing device in one embodiment. As shown in FIG. 3 , the process of performing signal conversion processing on the original reflection signal in the signal processing device to obtain the converted reflection signal includes steps S100 to S103:

S100, obtaining first near-field data of an original reflection signal;

The original reflection signal is the output result of the atomic microwave antenna, which characterizes the sampling characteristics of the atomic microwave antenna. By collecting the sampling characteristics of the atomic microwave antenna, the first near-field data of the original reflection signal is determined. Among them, the first near-field data is the near-field sampling result corresponding to the original reflection signal.

In one embodiment, FIG. 4 is a flow chart of a signal conversion processing method of a signal processing device in another embodiment. As shown in FIG. 4 , the process of obtaining the first near-field data of the original reflection signal in step S100 includes steps S200 and S201:

S200, performing preset sampling on the original reflected signal to obtain field distribution data of preset sampling points;

S201, determining first near-field data according to field distribution data.

The preset sampling includes multiple sampling methods such as near field sampling and point sampling, etc. The field distribution data of the preset sampling point is obtained by extracting information in the original reflection signal for characterizing the position point corresponding to the preset sampling point.

Furthermore, by determining the field distribution data, the first near-field data is substituted into a calculation formula of the sampling range to determine the first near-field data.

S101, performing mathematical transformation processing on the first near-field data to obtain far-field data of the original reflection signal;

S102, performing an inverse transformation of the mathematical transformation on the far-field data to obtain second near-field data of the original reflection signal;

S103: restore the transformed reflection signal according to the second near-field data.

Among them, through two mathematical transformations in step S101 and step S102, the error caused by different scanning intervals and working characteristics of Rydberg atoms in the reception of reflected waves by the atomic microwave antenna is reduced.

In one embodiment, the mathematical transformation includes Fourier transformation or linear frequency modulation z transformation, etc. As a preferred implementation, the mathematical transformation includes fast Fourier transformation. The near-field and far-field transformation of the near-field data corresponding to the original reflection signal is achieved by fast Fourier transformation.

Based on this, the receiving antenna is one of the key components, which directly determines the distance and accuracy of radar detection. In terms of radar detection distance, the following formula is followed:

Among them, _Pt is the radar's transmission power, G is the antenna gain, σ is the target's scattering cross-sectional area, λ is the radar signal wavelength, and _Simin is the minimum detectable signal power. It can be seen that the radar detection range is directly related to the minimum detectable signal power _Simin , as shown in the following formula:

_Simin = S*εE ² _min

Among them, S is the radar receiving area, and E _min is the minimum electric field amplitude that can be measured by the radar antenna unit. It can be seen that the maximum detection distance of the radar is R _max ∝E ^-1/2 . The receiving antennas of traditional microwave radars are usually antenna arrays made of metal. The detection accuracy of electromagnetic signals is subject to various constraints such as system size, shape, and working environment. 1mV/cm is the recognized minimum detectable electric field strength. The measurement accuracy of the atomic microwave antenna for the electric field has reached 8. From the above analysis, it can be seen that under the same conditions such as the transmitted signal power, gain, and target reflection cross section, the detection distance of the atomic microwave antenna for the reflected signal will be increased by more than 10 times.

Based on this, since the detection sensitivity of Rydberg atoms to electromagnetic waves is more than two orders of magnitude higher than that of metal electric dipole antennas, the detection distance of atomic microwave antennas based on Rydberg atoms will be greatly increased; due to the high detection sensitivity of Rydberg atoms, the signal-to-noise ratio of atomic microwave antennas will also be greatly improved, thereby improving the anti-interference ability of atomic microwave antennas; the response bandwidth of Rydberg atoms to microwaves is relatively small, which will reduce the filtering and noise reduction requirements of radar systems; the same Rydberg atomic module can respond to the frequency domain of RF electric fields from 1 GHz to 500 GHz, that is, covering from the microwave region to the lower edge of terahertz. Such a wide response range is much higher than that of traditional metal electric dipole antennas, which will make it very convenient to switch the working frequency of atomic microwave antennas based on Rydberg atoms, providing the convenience of one machine with multiple functions. The detection performance of traditional antennas is severely limited by the size of the antenna or antenna array. The detection accuracy of the Rydberg atomic microwave system has nothing to do with the size. Without affecting the performance, it can be miniaturized, integrated, and chip-based.

In any of the above-mentioned embodiments of the microwave antenna based on Rydberg atoms, the atomic microwave antenna outputs the original reflection signal according to the reflected wave received from the space scanning electromagnetic wave, and the signal processing device performs signal conversion processing on the original reflection signal to obtain the transformed reflection signal, and sends the transformed reflection signal to the radar signal processing device to instruct the radar signal processing device to display the radar signal according to the transformed reflection signal. Based on this, through the characteristics of Rydberg atoms such as high detection sensitivity, small response bandwidth to microwaves, and wide frequency domain, the radar antenna is endowed with advantages such as improved detection distance, anti-interference ability, convenience of frequency switching, and miniaturization. At the same time, through the signal conversion processing of the signal processing device, the signal accuracy based on Rydberg atom detection is improved.

The embodiment of the present invention also provides a microwave radar based on the Rydberg atomic antenna.

FIG5 is a structural diagram of a microwave radar module based on a Rydberg atomic antenna according to an embodiment of the present invention. As shown in FIG5 , the module includes a module 300, a module 301 and a module 302:

A microwave transmitting antenna array 300 is used to transmit space scanning electromagnetic waves;

In one embodiment, the microwave transmitting antenna array is used to transmit space scanning electromagnetic waves with a frequency of 1 GHz to 500 GHz. As a preferred implementation, the microwave transmitting antenna array is used to transmit space scanning electromagnetic waves with a frequency of 14 GHz.

In one embodiment, the microwave transmitting antenna array 300 includes a mechanical scanning antenna, a passive phased array antenna, an active phased array antenna, or the like.

The microwave antenna 301 based on Rydberg atoms of any of the above embodiments;

The microwave antenna 301 based on Rydberg atoms is used as a receiver to measure the distance of the target to be detected according to the return time of the reflected wave; the moving direction and speed of the object to be detected are detected according to the frequency composition of the microwave signal and through the Doppler effect. The above detection results are transformed and processed and then output as transformed reflected signals.

The radar signal processing device 302 is used to display the radar signal based on the transformed reflection signal of the microwave antenna based on the Rydberg atom.

The radar signal processing device 302 displays the image and motion parameters of the target to be detected according to the transformed reflected signal.

In one embodiment, FIG6 is a structural diagram of a microwave radar module based on a Rydberg atomic antenna according to another embodiment. As shown in FIG6 , a radar signal processing device 302 includes a digital signal processor 400 and a radar imaging system 401:

The digital signal processor 400 is used to process the transformed reflection signal output by the atomic microwave antenna.

The radar imaging system 401 is used to display the radar signal according to the processing result of the digital signal processor.

In any of the above-mentioned microwave radars based on Rydberg atomic antennas, the atomic microwave antenna outputs an original reflection signal according to the reflected wave received from the space scanning electromagnetic wave, and the signal processing device performs signal conversion processing on the original reflection signal to obtain a transformed reflection signal, and sends the transformed reflection signal to the radar signal processing device to instruct the radar signal processing device to display the radar signal according to the transformed reflection signal. Based on this, through the characteristics of Rydberg atoms such as high detection sensitivity, small response bandwidth to microwaves, and wide frequency domain, the radar antenna is endowed with advantages such as improved detection distance, anti-interference ability, convenience of frequency switching, and miniaturization. At the same time, through the signal conversion processing of the signal processing device, the signal accuracy based on Rydberg atomic detection is improved.

The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims (8)

1. A reed-burg atom based microwave antenna comprising:

The atomic microwave antenna comprises a Redberg atomic air chamber and is used for receiving reflected waves of space scanning electromagnetic waves and outputting original reflected signals according to the reflected waves;

The signal processing device is used for performing signal transformation processing on the original reflected signal to obtain a transformed reflected signal, and sending the transformed reflected signal to the radar signal processing device so as to instruct the radar signal processing device to display a radar signal according to the transformed reflected signal;

The atomic microwave antenna comprises a Redburg atomic air chamber, a detection laser, a coupling laser and a photoelectric detector; the Redberg atom air chamber stores Redberg heat atoms; the detection laser is used for emitting detection light, the coupling laser is used for emitting coupling light, wherein the detection light and the coupling light are used for exciting the Redberg heat atoms from a ground state to a Redberg state, and the detection light is also used for generating a quantum interference effect of Raman absorption; the photoelectric detector is used for detecting the cleavage width of the business Raman absorption peak, and solving the electric field strength to be detected so as to obtain the original reflection signal;

the process of performing signal transformation processing on the original reflected signal to obtain a transformed reflected signal includes the steps of:

acquiring first near field data of an original reflected signal;

Performing digital transformation processing on the first near-field data to obtain far-field data of the original reflected signal;

Performing inverse transformation processing on the far-field data to obtain second near-field data of the original reflection signal;

And restoring the transformed reflection signal according to the second near-field data.

2. The reed-burg atom based microwave antenna of claim 1, wherein the coupled light is blue detuned coupled light and the probe light is red detuned probe light;

Wherein the blue detuned coupled light has a detuning frequency of 70 to 130MHz; the red detuned probe light has a detuning frequency of 70 to 130MHz.

3. The reed-burg atom based microwave antenna of claim 2, wherein the blue detuned coupled light has a detuning frequency of 100MHz and a wavelength of 480nm; the detuning frequency of the red detuning detection light is 100MHz, and the wavelength is 780nm.

4. A microwave antenna based on a reed burg atom according to any of claims 1 to 3, wherein the reed burg thermal atom is a rubidium atom.

5. The reed-burg atom based microwave antenna of claim 4, wherein the process of acquiring the first near field data of the original reflected signal comprises the steps of:

performing preset sampling on the original reflected signal to obtain field distribution data of preset sampling points;

The first near field data is determined from the field distribution data.

6. A microwave antenna based on the reed-burg atoms as in claim 1 or 5, wherein the mathematical transformation process is a fast fourier transformation process.

7. A microwave radar based on a reed burg atomic antenna, comprising:

a microwave transmitting antenna array for transmitting spatially scanned electromagnetic waves;

A reed-burg atom based microwave antenna as claimed in any one of claims 1 to 6;

And the radar signal processing device is used for displaying radar signals according to the transformed reflected signals of the microwave antenna based on the Redberg atoms.

8. The reed burg atom antenna based microwave radar of claim 7, wherein the microwave transmitting antenna array is configured to transmit spatially scanned electromagnetic waves having a frequency of 1GHz to 500 GHz.