CN106501792A - A kind of reconstruct Optical Controlled Phased Array Antenna emitter exchanged based on light - Google Patents

Abstract

The invention discloses a reconstructed optically controlled phased array radar transmitter based on optical switching, which includes a power amplifier, an antenna array, a wave control computer, a laser, a microwave source, an optical modulator, a wavelength division multiplexer, a programmable optical Delay line, programmable optical attenuator, all-optical wavelength switch and photoelectric detector; the present invention organically combines the wavelength division multiplexing method with the all-optical wavelength switching method, and on the basis of the advantages of traditional optically controlled phased array radar, it also The dynamic reconstruction of the sub-array is realized, which can meet the simultaneous multi-target full-space tracking that cannot be realized by the traditional optically controlled phased array radar; the radar receiver is simple and easy to operate, reliable in performance and has a cost advantage.

Description

A Reconfigurable Optically Controlled Phased Array Radar Transmitter Based on Optical Switching

technical field

The invention relates to the technical field of optically controlled phased array radar, in particular to a reconstructed optically controlled phased array radar transmitter based on optical switching.

Background technique

Compared with the traditional mechanical scanning radar antenna, the phased array antenna realized by modern electronic technology has great advantages in terms of response speed, target update rate, multi-target tracking ability, resolution, and versatility. The phased array antenna uses a specific feeding method, intelligent control and adjustment of the amplitude and phase of the array element to make the beamforming non-inertial and flexible scanning, thereby greatly improving the information acquisition and update rate. In a phased array antenna system, the beam scanning is formed by adjusting the phase relationship between the radiating elements, so the signal distribution method required to obtain the necessary phase relationship between the elements is a key. However, there are still many problems in the full electronic control of the phased array antenna unit. The main reason is that the phased array antenna can only scan in a relatively narrow signal bandwidth due to the limitation of the aperture transit time, which limits its wideband and The performance of wide-angle scanning seriously restricts the application of phased array antennas in complex environments and high-performance fields.

There are many methods for antenna multi-beam formation, such as Blass method, Buter multi-beam matrix method, all-digital multi-beam (DBF) method and sub-antenna array method, etc. For the common DBF and sub-antenna array methods in receiving antennas, The advantage of the all-digital multi-beam method is high performance and easy to realize continuous sliding scanning. The disadvantage is that the number of channels is large and the cost is high. The advantage of the sub-antenna array method is that it reduces complexity and saves money. The level is raised and the working bandwidth is narrowed.

Today's extremely rapid development of photon technology centered on semiconductor lasers, integrated optics, and optical fiber technology is most likely to bring technological breakthroughs to microwave phased array radar systems and solve this problem. As the most ideal signal transmission medium, optical fiber has extremely low transmission loss (the transmission loss of ordinary single-mode optical fiber is within 0.2dB/km), light weight, small size, high efficiency, and anti-electromagnetic radiation and various electromagnetic interference capabilities, etc. Advantages; In addition, optical fiber also has extremely huge signal bandwidth capability. The single-channel wavelength signal transmission rate of optical fiber communication transmission system can reach hundreds of Gbit/s. With the help of dense wavelength division multiplexing technology, one optical fiber can transmit up to hundreds of Gbit/s. A signal with T bit/s capacity.

Using optical fiber and photonic devices to realize the true delay OTTD microwave photon beamforming of the optical signal of the radar antenna receiving unit can overcome the working bandwidth bottleneck effect caused by the beam tilt of the phased array antenna, and provide a very high efficiency for the microwave phased array radar system Working bandwidth. In the tens of GHz microwave frequency range, the optically controlled phase array can obtain almost flat signal system response. At the same time, in the light wave environment, it is easy to achieve phase and amplitude compensation and fast signal processing, which is conducive to suppressing side lobes and realizing rapid scanning of radar beams, improving system performance; using photonic devices such as fiber optic switches and wavelength routing to easily realize optical control Beam forming network The rapid switching and reconfiguration of optically controlled phased array beams meets the needs of flexible control functions such as spatial multi-beam, beam shape agility, and sub-array reorganization.

Contents of the invention

In order to solve the problem of the bottleneck effect of beam tilt and working bandwidth of the traditional phased array antenna, the present invention provides a reconstructed optically controlled phased array radar transmitter based on optical switching, which can provide a very high working bandwidth and is easy to realize Rapid scanning of the radar beam improves system performance.

A reconstructed optically controlled phased array radar transmitter based on optical switching, including a power amplifier, an antenna array, a wave control computer, a laser, a microwave source, an optical modulator, a wavelength division multiplexer, a programmable optical delay line, and programming optical attenuator, all-optical wavelength switch and photoelectric detector; the laser emits multiple channels of optical carrier, and the optical modulator modulates the radar signal output by the microwave source onto the optical carrier, and the optical carrier carrying the radar signal passes through After the wavelength division of the wavelength division multiplexer, the delay adjustment of the programmable optical delay line is input respectively, and then the power is adjusted by the programmable optical attenuator, and then input into the all-optical wavelength switch for wavelength exchange, and the output sub-array is obtained, and the signal of the output sub-array is passed through the photoelectric The detector is converted into a radio frequency signal, and the radio frequency signal is amplified by a power amplifier and radiated to space through an antenna array; the wave control computer simultaneously controls a programmable optical delay line, a programmable optical attenuator and an all-optical wavelength switch.

The laser is a multi-wavelength array laser, and the output wavelength is the ITU wavelength of the C-band of optical fiber communication; it is used to provide optical carriers for multiple optical-carrying radio frequency transmission channels.

The microwave source is a microwave signal source with low phase noise and is used to generate broadband radar signals.

The optical modulator is a Mach-Zehnder intensity modulator or an electroabsorption modulator, which is used to modulate the radar signal emitted by the microwave source onto the optical carrier.

The wavelength division multiplexer is used to decompose the optical carrier carrying the radar signal into several channels, and each channel only contains one ITU wavelength.

The programmable optical delay line is a binary optical fiber delay line device composed of several 2-in, 2-out digitally controlled optical switches and several optical delay lines, and each channel is connected to a programmable optical delay line for switching between different channels. The relative delay is adjusted.

The programmable optical attenuator is used to adjust the intensity of the optical signal of each channel, and jointly adjusts the attenuation and phase of each channel in combination with the programmable optical delay line to realize beam forming.

The all-optical wavelength switch is an N-in N-out all-optical wavelength switch matrix. The N input channels are divided into m groups according to the wavelength, and each group uses a multi-wavelength array laser containing N/m ITU wavelengths as the carrier, and is composed of N/m wavelength channels after modulation and wavelength division multiplexing An input subarray. The N output channels are also divided into m output sub-arrays, each output sub-array contains the same number of wavelengths and wavelengths as each input sub-array, but the wavelength of each output sub-array can be passed through the entire The optical wavelength switch selects from all wavelengths of all input subarrays. Each channel of the output sub-array corresponds to the physical position of each antenna, and the antenna position corresponding to each input sub-array is determined according to the result of optical switching; the all-optical wavelength switch makes the input sub-array There is a one-to-one correspondence with the output sub-array.

The photodetector converts the optical signal output by each channel into a radio frequency signal for output.

The wave control computer simultaneously controls the programmable optical delay line, the programmable optical attenuator and the all-optical wavelength switch, so as to realize the control and reconstruction of the optically controlled phased array beam.

The power amplifier amplifies the radio frequency signal output by the photodetector to obtain a high power radio frequency signal output.

The antenna array radiates the amplified radio frequency signal into physical space.

The number of lasers, microwave sources, optical modulators, wavelength division multiplexers, programmable optical delay lines, programmable optical attenuators, photodetectors, and power amplifiers is determined according to the number of sub-arrays and the number of antenna arrays. The number of programmed optical delay lines, programmable optical attenuators, photodetectors, and power amplifiers is equal to the number of antenna arrays; the number of lasers, microwave sources, optical modulators, and wavelength division multiplexers is equal to the number of sub-arrays.

The method for realizing the dynamic reconfiguration of sub-arrays in a reconfigurable optically controlled phased array radar transmitter based on optical switching is as follows: modulate the radar signal to be transmitted onto all ITU wavelengths of the multi-wavelength optical carrier to The square number of ITU wavelengths is used as the carrier of an input sub-array, and all the optical carriers of the input sub-array are input into the all-optical wavelength switch. All the outputs of the switch are grouped into several output sub-arrays. The input subarray contains as many wavelengths as there are wavelengths. Each wavelength of the output sub-array is subjected to photoelectric detection and power amplification respectively, and then radiated out from the antenna array. Continuously rearrange the ITU wavelengths according to the square unit in a large front space, and realize the dynamic mapping between the input sub-array and the output sub-array through the wavelength exchange of the switch, then the antenna unit corresponding to each input sub-array or The physical space can be changed to achieve reconstruction.

The advantages of this joint wave-steering multi-beam structure based on the wavelength division multiplexing optical delay line method are:

(1) The wave control method of photoelectric fusion can effectively reduce the bottleneck effect of the beam tilt and working bandwidth of the traditional electronic phased array. Compared with the all-optical phased array controlled by all primitives, the cost is relatively low and the implementation effect is better , has a great practical prospect;

(2) The multi-beam dynamic reconfiguration array and wave control method based on optical wavelength allocation rearrangement and optical matrix switch exchange can reduce the limitation of aperture transit time, and can realize multi-target beamforming and continuous tracking in the whole airspace;

(3) Make full use of optical wavelength division multiplexing and all-optical switching, the network structure is flexible, and the networking cost is low;

(4) Each optical transmission wavelength branch has optical power amplitude adjustment control, which can realize branch amplitude weighting of beam synthesis, has the effect of suppressing side lobes, and has signal processing functions.

Description of drawings

Fig. 1 is a block diagram of the present invention;

Fig. 2 is a schematic diagram of the principle of the present invention;

Fig. 3 is a schematic diagram of the arrangement of the optical carrier wavelengths input into the sub-array according to the spatial adjacent relationship.

detailed description

In order to describe the present invention more specifically, the technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, the reconstructed optically controlled phased array radar transmitter based on optical switching includes multi-wavelength array lasers, microwave sources, optical modulators, wavelength division multiplexers, programmable optical delay lines, and programmable optical attenuation laser, all-optical wavelength switch, photoelectric detector, power amplifier, antenna array, and wave control computer; the laser emits multiple channels of optical carrier, and the optical modulator modulates the radar signal output by the microwave source onto the optical carrier, carrying the radar signal After the optical carrier wave is divided by the wavelength division multiplexer, it is respectively input into the programmable optical delay line for delay adjustment, and then the power is adjusted by the programmable optical attenuator, and then input into the all-optical wavelength switch for wavelength exchange to obtain the output sub-array, the output sub-array The signal is converted into a radio frequency signal by a photodetector, and the radio frequency signal is amplified by a power amplifier and radiated into space through an antenna array; the wave control computer simultaneously controls a programmable optical delay line, a programmable optical attenuator and an all-optical wavelength switch to realize True time delay and dynamic reconstruction of sub-array for optically controlled phased array radar.

As shown in Figure 2, the method of an embodiment of the present invention is as follows:

The optical signal containing 36 ITU wavelengths output by the multi-wavelength array laser is selected as the optical carrier of the input subarray 1, the optical modulator modulates the radar signal to be transmitted onto the optical carrier, and uses the wavelength division multiplexer to convert the optical carrier It is decomposed into 36 channels, and the optical carrier of each channel passes through a programmable optical delay line and a programmable optical attenuator to adjust the relative delay and attenuation between channels. Finally, the optical carriers of several input sub-arrays are sent to the all-optical wavelength switch for switching, and several output sub-arrays are obtained, and each output sub-array contains 36 ITU wavelengths that are the same as the input sub-arrays. Each wavelength channel of the output sub-array uses a photodetector to convert the optical signal into a radio frequency signal, amplifies it through a power amplifier, and then radiates it into space through the antenna array.

Any physical port input of an all-optical wavelength switch can be switched to any output port without blocking. Its input is a multi-channel radar signal weighted by phase and amplitude, and the radar signal is radiated from the antenna array on the front after being converted by a photodetector and amplified by a power amplifier. In this process, each radar signal input into the sub-array establishes a one-to-one correspondence with a physical area in the antenna array through the connection of the optical switch. Through the wavelength exchange of the optical switch, changing the corresponding relationship between the input and the output can realize that the radar signal of a certain sub-array can be transmitted at different positions of the antenna array, thereby greatly improving the radar's ability to track and detect targets.

As shown in Figure 3, it is assumed that the antenna unit of the output sub-array 1 originally corresponds to the wavelength of the input sub-array in the upper solid line, and is switched through the optical switch matrix switch, so that the antenna unit of the output sub-array 1 corresponds to the input sub-array in the lower dotted line. The 36 wavelengths in this sub-array may be wavelengths from different input sub-arrays. This matrix switching method can easily realize the scanning of the whole airspace. For multi-target tracking, the corresponding input sub-array can be allocated according to the target.

The multi-byte optical delay line and optical attenuator of each wavelength channel in the sub-array are controlled by the computer to quickly switch, so as to realize the phase and amplitude weighting of the microwave signal transmitted in the corresponding sub-array, so as to suppress the side lobe and reduce the beam width and other signal processing. In addition, multiple sub-arrays can also work together or jointly to form a combined beam to achieve complex function measurement, control and tracking. This subarray control technology can realize multi-target beamforming and continuous tracking in the whole airspace, greatly reduce the limitation of aperture transit time, and improve the working bandwidth and scanning angle range of the phased array antenna.

The above description of the embodiments is for those of ordinary skill in the art to understand and apply the present invention. It is obvious that those skilled in the art can easily make various modifications to the above-mentioned embodiments, and apply the general principles described here to other embodiments without creative efforts. Therefore, the present invention is not limited to the above-mentioned embodiments, and improvements and modifications made by those skilled in the art according to the disclosure of the present invention should fall within the protection scope of the present invention.

Claims (7)

1. A reconfigurable optically controlled phased array radar transmitter based on optical switching, characterized in that it comprises a power amplifier, an antenna array, a wave control computer, a laser, a microwave source, an optical modulator, a wavelength division multiplexer, and programming optical delay line, programmable optical attenuator, all-optical wavelength switch and photoelectric detector; The optical carrier wave of the radar signal is separately input to the programmable optical delay line for delay adjustment after wavelength division by the wavelength division multiplexer, and then the power is adjusted by the programmable optical attenuator, and then input to the all-optical wavelength switch for wavelength exchange, and the output sub-array is obtained, and the output The signal of the sub-array is converted into a radio frequency signal by a photodetector, and the radio frequency signal is amplified by a power amplifier and radiated to space through the antenna array; the wave control computer simultaneously controls the programmable optical delay line, the programmable optical attenuator and the all-optical wavelength switch. 2. The reconfigurable optically controlled phased array radar transmitter based on optical switching according to claim 1, wherein the laser is a multi-wavelength array laser. 3. The reconfigurable optically controlled phased array radar transmitter based on optical switching according to claim 1, wherein the optical modulator is a Mach-Zehnder intensity modulator or an electroabsorption modulator. 4. The reconfigurable optically controlled phased array radar transmitter based on optical switching as claimed in claim 1, wherein the programmable optical delay line is composed of several 2-in 2-out digitally controlled optical switches and several optical Composition of delay lines. 5 . The reconfigurable optically controlled phased array radar transmitter based on optical switching according to claim 1 , wherein the optical switch is an all-optical wavelength switch matrix with N in and N out. 6. The reconfigurable optically controlled phased array radar transmitter based on optical switching as claimed in claim 1, wherein said programmable optical delay line, programmable optical attenuator, photodetector, power amplifier The number of is equal to the number of antenna arrays. 7. the reconfigurable optically controlled phased array radar transmitter based on optical exchange as claimed in claim 1, is characterized in that, the number of described laser device, microwave source, optical modulator, wavelength division multiplexer and sub- Arrays are equal in number.