Amplitude and phase control method of microwave photonic component and microwave photonic component

Abstract

The present invention relates to an amplitude and phase control method of a microwave photonic component and a microwave photonic component, and belongs to the field of microwave photonic link control. The present invention controls a radio frequency attenuator and a radio frequency phase shifter in a signal channel through a control circuit designed based on an FPGA, and then performs closed-loop control on the corresponding amplitude values ​​and phase values ​​of multiple signal channels collected in real time. The problem of slow control speed when amplitude and phase control are performed on radio frequency signals in multiple signal channels is effectively solved.

Description

Technical Field

[0001] The invention relates to an amplitude and phase control method of a microwave photon component and a microwave photon component, belonging to the field of microwave photon link control. Background Art

[0002] Microwave photonics is an interdisciplinary subject about microwave signals and optical signals. It processes microwave signals by studying the processing of optical signals to improve the overall performance of microwave links. Microwave photonic technology can achieve low-loss, long-distance, wide-bandwidth and anti-interference large-dynamic signal transmission of microwave signals, and plays an increasingly important role in satellite communications, electronic countermeasures and modern radar applications. With the influence of the integration and lightweight trends of telecommunications and military equipment, the demand for high-density, arrayed and multifunctional microwave photonic components has become increasingly obvious. In the wave control system of phased array radar, amplitude and phase control needs to realize rapid regulation of the amplitude and phase of each radiating unit. It is the main functional unit for realizing beam scanning and the core component of the phased array system.

[0003] In the past, in microwave photonic components used in phased array systems, since the number of signal channels was not high, a single-chip microcomputer was used to achieve amplitude control, which not only met the control requirements but also reduced costs. However, with the increasing demand for multiple signal channels, the amplitude control speed is slow due to the limitations of the processing mechanism and port resources of the single-chip microcomputer. In addition, the existing microwave photonic components used in phased array systems usually only integrate amplitude control functions, and do not include switching, phase shifting, and combining functions. Especially in application scenarios where multi-channel signals need to be phase shifted and amplitude modulated, the increase in control ports forces the microwave photonic components to adopt a cascaded design of a single-chip microcomputer, which makes the control delay as high as milliseconds, restricting the sensitivity of the wave control system. In addition, such a design causes the product to be large in size and complex in structure. Summary of the invention

[0004] The object of the present invention is to provide an amplitude and phase control method of a microwave photonic component and a microwave photonic component, so as to solve the problem of slow adjustment speed when performing amplitude and phase control on the microwave photonic component.

[0005] To achieve the above object, the solution of the present invention includes:

[0006] The present invention provides an amplitude and phase control method for a microwave photonic component, comprising the following steps: using the amplitude values ​​and phase values ​​of radio frequency signals of multiple signal channels in a microwave photonic link collected in real time as feedback values, using the preset amplitude control value and phase control value of the radio frequency signal in the corresponding signal channel as target values, and controlling the radio frequency attenuator and the radio frequency phase shifter in the corresponding signal channel by using a control circuit designed by FPGA for controlling the amplitude and phase of the radio frequency signal to perform closed-loop control on the corresponding amplitude value and phase value.

[0007] Furthermore, the signal channel also includes a radio frequency switch, and the control circuit controls the radio frequency switch in the corresponding signal channel to control the on and off of the corresponding signal channel.

[0008] Further, the RF attenuator is installed upstream of the RF phase shifter in the corresponding signal channel, and the RF switch is installed upstream of the RF attenuator in the corresponding signal channel.

[0009] Furthermore, the control circuit includes an SPI serial interface for transmitting control signals, an FPGA chip for controlling an RF switch, an RF attenuator and an RF phase shifter, a power supply module for powering the FPGA chip, a crystal oscillator for providing a fixed-frequency clock signal for the FPGA chip, a FLASH for storing an FPGA chip port configuration program, and an EEPROM for storing an amplitude and phase control program.

[0010] A microwave photonic component comprises a plurality of signal channels for transmitting radio frequency signals, wherein the signal channels comprise radio frequency attenuators for adjusting the amplitude of radio frequency signals and radio frequency phase shifters for adjusting the phase of radio frequency signals; and a control circuit for controlling the amplitude and phase of radio frequency signals in corresponding signal channels, wherein the control circuit is designed based on FPGA, and uses the amplitude values ​​and phase values ​​of radio frequency signals of the plurality of signal channels collected in real time as feedback values, and uses the amplitude control values ​​and phase control values ​​of the radio frequency signals in the corresponding signal channels set in advance as target values, and the control circuit controls the radio frequency attenuators and radio frequency phase shifters in the corresponding signal channels, and performs closed-loop control on the corresponding amplitude values ​​and phase values.

[0011] Furthermore, the signal channel also includes a radio frequency switch, and the control circuit controls the radio frequency switch in the corresponding signal channel to control the on and off of the corresponding signal channel.

[0012] Further, the RF attenuator is installed upstream of the RF phase shifter in the corresponding signal channel, and the RF switch is installed upstream of the RF attenuator in the corresponding signal channel.

[0013] Furthermore, the signal channel also includes a photodetector and a first-stage RF amplifier; the photodetector, the first-stage RF amplifier, the RF switch, the RF attenuator, and the RF phase shifter are cascaded in sequence; the RF signal of each signal channel then passes through an RF combiner to combine the RF signals of multiple signal channels into one RF signal, and the combined RF signal then passes through an equalizer for compensating for amplitude distortion of the RF signal and a second-stage RF amplifier in sequence to output the final RF signal.

[0014] Furthermore, the photodetector, the first-stage radio frequency amplifier, the radio frequency combiner, the equalizer, and the second-stage radio frequency amplifier are packaged in the same airtight tube shell.

[0015] Furthermore, the control circuit includes an SPI serial interface for transmitting control signals, an FPGA chip for controlling an RF switch, an RF attenuator and an RF phase shifter, a power supply module for powering the FPGA chip, a crystal oscillator for providing a fixed-frequency clock signal for the FPGA chip, a FLASH for storing an FPGA chip port configuration program, and an EEPROM for storing parameters related to amplitude and phase control.

[0016] The beneficial effects of the present invention are as follows: the present invention is a pioneering invention, which controls the RF attenuator and RF phase shifter in the signal channel through a control circuit designed based on FPGA, and then performs closed-loop control on the corresponding amplitude values ​​and phase values ​​of multiple signal channels collected in real time. The problem of slow control speed when the amplitude and phase of RF signals in multiple signal channels are controlled is effectively solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of a microwave photonic assembly of the present invention;

[0018] Figure 2 It is a structural component of the microwave photonic component of the present invention.

[0019] In the figure: 1. lower cover; 2. control circuit; 3. optical fiber; 4. tube shell; 5. glass insulation terminal; 6. photodetector; 7. ceramic substrate; 8. RF attenuator; 9. RF switch; 10. first-stage RF amplifier; 11. RF phase shifter; 12. RF combiner; 13. upper cover; 14. SSMP RF connector; 15. equalizer; 16. second-stage RF amplifier; 17. microstrip transmission line. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0021] The concept of the present invention is to use FPGA (Field Programmable Gate Array) to perform closed-loop control on radio frequency signals of multiple signal channels collected in real time.

[0022] Method Example:

[0023] This embodiment provides an amplitude and phase control method for a microwave photonic component. When controlling the amplitude and phase of a microwave photonic component, FPGA technology is used to control the amplitude and phase collected in real time to the preset target values ​​encapsulated in the program. The overall functional block diagram of the microwave photonic component is shown in FIG. Figure 1As shown, a microwave photon link for converting an optical signal into a radio frequency signal and transmitting the radio frequency signal includes a photodetector (photodetector), a radio frequency amplifier (amplification), a radio frequency switch (switch), a radio frequency attenuator (attenuation), a radio frequency phase shifter (phase shift), a radio frequency combiner (combiner) for compensating for the amplitude distortion of the radio frequency signal, and an equalizer (equalization); a signal channel for transmitting the radio frequency signal includes a photodetector, a radio frequency amplifier, a radio frequency switch, a radio frequency attenuator, and a radio frequency phase shifter. A control circuit for controlling the amplitude and phase of the radio frequency signal includes an FPGA chip, an SPI interface, a power supply module, a crystal oscillator, a FLASH, and an EEPROM. The microwave photon link designs the corresponding number of signal channels according to specific needs. The present invention is explained below using 12 signal channels as an example.

[0024] The control circuit based on FPGA chip is used to control the RF switch, RF attenuator and RF phase shifter in the microwave photonic circuit, so as to achieve the purpose of controlling the on and off of the signal channel, the amplitude and phase of the RF signal. Among them, the EEPROM chip instant storage port stores the setting information for controlling the amplitude and phase of the RF signal. When the microwave photonic component loses power, the setting information will not be lost. When the microwave photonic component is powered on again, the FPGA chip reads the setting information and restores the control state of the amplitude and phase of the microwave photonic component. The FPGA chip reads the setting information to realize the control of the RF switch, 4-bit RF attenuator and 6-bit RF phase shifter of 12 signal channels with a total of 132 nodes. The setting information includes the preset amplitude control target value, phase control target value and control algorithm. The FLASH chip stores the port configuration program of the FPGA; the crystal oscillator provides a fixed frequency clock signal for the FPGA, such as 36MHz; the power module realizes the timing power-on of the core, DRAM and BANK in the FPGA; and uses the SPI serial interface for communication, transmits control signals and reports the current state of the microwave photonic component, and the control delay is less than 1us. The FPGA chip performs closed-loop control on the RF signal amplitude and phase of the corresponding signal channel fed back in real time according to the RF signal amplitude and phase control target value of the corresponding signal channel, so that the amplitude and phase of the RF signal reach the target value. And according to actual needs, such as controlling the transmission path of the RF signal, the purpose of controlling the on and off of a certain signal channel is achieved by controlling the RF switch.

[0025] This embodiment provides a microwave photonic component suitable for the present invention, and its split diagram is as follows: Figure 2 As shown, the photodetector, RF amplifier, RF switch, RF attenuator, RF phase shifter, RF combiner and equalizer are integrated in the same airtight tube shell, and the control circuit is designed based on the FPGA chip. The control circuit is electrically connected to the airtight tube shell to form a microwave photonic assembly suitable for the present invention.

[0026] The following is a specific process to explain the design of the microwave photonic component:

[0027] The present invention customizes a bevel lens optical fiber 3 with high reflectivity, so that the incident light enters the photosensitive surface of the optical detector after total reflection at the end face of the optical fiber, thereby realizing demodulation of the optical signal to the radio frequency signal. The optical detector chip is fixed on the ceramic substrate 7 by conductive glue, and the output impedance of the optical detector chip is matched to 50 ohms by matching network design.

[0028] After passing through the photodetector 6, the 12 optical signals are demodulated into 12 RF signals, and then pass through the RF switch 9, the RF attenuator 8, the first-stage RF amplifier 10, the RF phase shifter 11, the two-stage RF combiner 12, the equalizer 15, the second-stage RF amplifier 16 and the microstrip transmission line 17, and finally output the RF signal through the SSMP RF connector 14. Among them, the design of placing a tungsten copper gasket at the bottom of the first-stage RF amplifier chip and the second-stage RF amplifier chip can not only meet the expansion coefficient and heat dissipation requirements, but also improve the RF transmission performance by reducing the height difference between the cascaded chips. The control circuit 2 on the control board of the lower cavity is connected to the chip of the upper cavity through the glass insulation terminal 5 to realize the power supply, RF switch, RF attenuator and RF phase shifter of each chip. The control board, RF chip, tungsten copper gasket and microstrip transmission line 17 are bonded to the shell through conductive glue and shared ground, and the transmission of RF signals is realized between the chips through gold wire bonding. One end of the SSMP RF connector 14 is fixed to the tube shell 4 through a solder ring, and is interconnected with the microstrip transmission line 17 by spot welding a gold strip to achieve RF signal output with low reflection loss.

[0029] The microwave photon assembly needs to be tested before sealing, and sealed after the indicators are qualified. The shell material is made of silicon aluminum alloy to ensure its good thermal conductivity and expansion characteristics. The shell is electroplated with nickel gold to meet the requirements of corrosion resistance and conductivity. The upper cover plate 13 and the lower cover plate 1 are sealed with the shell by laser sealing to meet the airtightness requirements of the microwave photon assembly.

[0030] Component Example:

[0031] This embodiment provides a microwave photonic component. The composition and connection method of the microwave photonic component adopt the design method introduced in the method embodiment. Since the introduction of the design method is clear enough, it will not be repeated here.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for amplitude and phase control of a microwave photonic component, characterized in that: The invention comprises the following steps: taking the amplitude value and phase value of the radio frequency signals of multiple signal channels in the microwave photon link collected in real time as feedback values, taking the amplitude control value and phase control value of the radio frequency signal in the corresponding signal channel set in advance as target values, controlling the radio frequency attenuator and radio frequency phase shifter in the corresponding signal channel by using a control circuit designed by FPGA for controlling the amplitude and phase of the radio frequency signal, and performing closed-loop control on the corresponding amplitude value and phase value; the signal channel also comprises a photoelectric detector, a radio frequency switch and a radio frequency combiner, the control circuit controls the radio frequency switch in the corresponding signal channel, controls the on-off of the corresponding signal channel, and the radio frequency combiner is used to combine multiple amplitude modulated and phase modulated radio frequency signals into one radio frequency signal; the optical signal of each signal channel is demodulated into a radio frequency signal by a photoelectric detector, and then the radio frequency signal is output after passing through the radio frequency switch, the radio frequency attenuator, the radio frequency phase shifter and the radio frequency combiner.

2. The amplitude and phase control method of a microwave photonic component according to claim 1, characterized in that: The radio frequency attenuator is installed upstream of the radio frequency phase shifter in the corresponding signal channel, and the radio frequency switch is installed upstream of the radio frequency attenuator in the corresponding signal channel.

3. The amplitude and phase control method of a microwave photonic component according to claim 1, characterized in that: The control circuit includes an SPI serial interface for transmitting control signals, an FPGA chip for controlling the RF switch, RF attenuator and RF phase shifter, a power supply module for powering the FPGA chip, a crystal oscillator for providing a fixed-frequency clock signal for the FPGA chip, a FLASH for storing the FPGA chip port configuration program, and an EEPROM for storing the amplitude and phase control program.

4. A microwave photonic component, characterized in that: The invention comprises a plurality of signal channels for transmitting radio frequency signals, wherein the signal channels comprise a photoelectric detector (6), a radio frequency switch (9), a radio frequency attenuator (8) for adjusting the amplitude of the radio frequency signal, a radio frequency phase shifter (11) for adjusting the phase of the radio frequency signal, and a radio frequency combiner (12); and a control circuit for controlling the amplitude and phase of the radio frequency signals in the corresponding signal channels. The control circuit is designed based on an FPGA, and uses the amplitude and phase values ​​of the radio frequency signals in the plurality of signal channels collected in real time as feedback values, and uses the amplitude control value and phase control value of the radio frequency signals in the corresponding signal channels set in advance as target values. The control circuit controls the radio frequency attenuator (8) and the radio frequency phase shifter (11) in the corresponding signal channels to perform closed-loop control on the corresponding amplitude and phase values. The control circuit controls the radio frequency switch (9) in the corresponding signal channels to control the on and off of the corresponding signal channels. The radio frequency combiner (12) is used to combine the multiple amplitude modulated and phase modulated radio frequency signals into one radio frequency signal. The optical signals in the respective signal channels are demodulated into radio frequency signals by the photoelectric detector, and then the radio frequency signals are output after passing through the radio frequency switch, the radio frequency attenuator, the radio frequency phase shifter, and the radio frequency combiner.

5. The microwave photonic component according to claim 4, characterized in that: The radio frequency attenuator (8) is installed upstream of the radio frequency phase shifter (11) in the corresponding signal channel, and the radio frequency switch (9) is installed upstream of the radio frequency attenuator (8) in the corresponding signal channel.

6. The microwave photonic component according to claim 4, characterized in that: The signal channel also includes a first-stage radio frequency amplifier (10); the photodetector (6), the first-stage radio frequency amplifier (10), the radio frequency switch (9), the radio frequency attenuator (8), and the radio frequency phase shifter (11) are sequentially cascaded; the radio frequency signal of each signal channel then passes through a radio frequency combiner (12) so that the radio frequency signals of multiple signal channels are combined into one radio frequency signal; the combined radio frequency signal then passes through an equalizer (15) for compensating for amplitude distortion of the radio frequency signal and a second-stage radio frequency amplifier (16) in sequence to output a final radio frequency signal.

7. The microwave photonic component according to claim 6, characterized in that: The photoelectric detector (6), the first-stage radio frequency amplifier (10), the radio frequency combiner (12), the equalizer (15), and the second-stage radio frequency amplifier (16) are packaged in the same airtight tube shell.

8. The microwave photonic component according to claim 4, characterized in that: The control circuit includes an SPI serial interface for transmitting control signals, an FPGA chip for controlling the RF switch, RF attenuator and RF phase shifter, a power supply module for powering the FPGA chip, a crystal oscillator for providing a fixed-frequency clock signal for the FPGA chip, a FLASH for storing the FPGA chip port configuration program, and an EEPROM for storing parameters related to amplitude and phase control.

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