Large-range tunable high-frequency microwave generating device and method based on photoconductive device

Abstract

The present invention provides a device and method for generating a wide range of tunable high-frequency microwaves based on photoconductive devices. The device comprises a high-voltage power supply, a microwave radio frequency transmission structure, a tunable laser driving source and an antenna. The present invention utilizes the linear working mode of a wide-bandgap photoconductive semiconductor device. Under the action of an external bias voltage, a tunable pulse cluster laser driving source is used to irradiate the wide-bandgap photoconductive semiconductor device, modulate and generate a high-frequency electrical signal, and generate a microwave signal through antenna radiation output, thereby realizing a high-frequency microwave output with a wide range of tunable frequency. The present invention improves the photoelectric conversion efficiency of the system, can realize a narrow-spectrum microwave output with a wide range of tunable frequency (0.5 GHz to 50 GHz), and realizes the efficient extraction of a wide range of tunable high-frequency microwaves. The present invention provides technical support for the development of a wide range of tunable high-power microwave integrated systems.

Description

Technical Field

[0001] The present invention relates to a high-frequency microwave generating device and method, and in particular to a wide-range tunable high-frequency microwave generating device and method based on a wide-bandgap photoconductive device. Background Art

[0002] Traditional high-power microwave sources use electron beam vacuum electronic devices and high-frequency electromagnetic structures to generate microwaves, and their operating frequencies are usually relatively fixed and difficult to adjust. Therefore, in recent years, tunable microwave technology using power electronic devices and photoconductive semiconductor devices has attracted widespread attention. Among them, wide-bandgap photoconductive semiconductor devices have many outstanding advantages, such as fast turn-on time, high synchronization accuracy, low time jitter, low turn-on inductance, etc. These unique advantages make photoconductive semiconductor devices widely used in solid-state compact pulse power sources, high-power ultra-wideband microwave radiation sources, dielectric wall accelerators, trigger systems for large pulse power devices, terahertz radiation and other pulse power research fields.

[0003] At present, the use of wide bandgap photoconductive semiconductors to generate tunable radio frequency microwaves is a new technology with important application prospects. In practical applications, wide bandgap photoconductive semiconductor devices have many excellent characteristics such as high critical breakdown electric field, high carrier mobility, high electron saturation drift velocity, high thermal conductivity, and related research work is also increasing. Planar electrode photoconductive devices have the advantage of fast response speed, but on the one hand, they are limited by the surface withstand voltage insulation capacity, the power of photoconductive devices is low, and under high voltage and high current conditions, the working life of wide bandgap photoconductive semiconductor devices is limited; on the other hand, for wide bandgap photoconductive semiconductor devices with large on-resistance, considering the microwave output on the back-end load, it is necessary to design a corresponding circuit structure to match it. Therefore, there is currently no application technology based on wide bandgap planar electrode photoconductive devices to generate large-range tunable high-frequency microwaves. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a large-range tunable high-frequency microwave generating device and method based on photoconductive devices. The large-range tunable high-frequency microwave generating device based on photoconductive devices comprises: a high-voltage power supply, a microwave radio frequency transmission structure, a tunable laser driving source and an antenna. The microwave radio frequency transmission structure comprises a planar electrode type photoconductive device and a high-frequency microstrip line. The planar electrode type photoconductive device is arranged on a substrate of the high-frequency microstrip line. The high-frequency microstrip line comprises an input end microstrip line and an output end microstrip line. Two planar electrodes of the planar electrode type photoconductive device are respectively connected to the input end microstrip line and the output end microstrip line. A radio frequency interface is arranged at the tail end of the output end microstrip line. The high-voltage power supply is connected to a planar electrode of the planar electrode type photoconductive device through the input end microstrip line. The antenna is connected to another planar electrode of the planar electrode type photoconductive device through the radio frequency interface and the output end microstrip line. The output end of the tunable laser driving source is connected to the planar electrode type photoconductive device.

[0005] The planar electrode type photoconductive device comprises a photoconductive semiconductor chip, a planar electrode and a transparent insulating film. A pair of planar electrodes are arranged side by side on the surface of the photoconductive semiconductor chip, and the remaining surface is a transparent insulating film. The planar electrodes are all Ni / Ti / Au three-layer metal electrodes, and the three metal layers of Ni, Ti and Au are arranged from bottom to top.

[0006] The photoconductive semiconductor wafer material of the planar electrode type photoconductive device is 4H-SiC or 6H-SiC.

[0007] The substrate of the high-frequency microstrip line is a high-speed plate, and the output end microstrip line is matched and connected with a coaxial radio frequency interface.

[0008] The tunable laser driving source adopts a high-power tunable pulse cluster laser light source system based on acousto-optic / electro-optic modulation, which includes a pulse laser seed source, an acousto-optic modulator, an electro-optic modulator, a fiber amplifier and a solid amplifier connected in sequence.

[0009] The high voltage power supply adopts a commercial 30kV high voltage continuous charging power supply to provide a bias voltage for the wide bandgap photoconductive device.

[0010] The antenna is a flat broadband radiation horn with impedance matching with the microwave radio frequency transmission structure.

[0011] The present invention provides a method for generating high-frequency microwaves with a large range of tunability based on a photoconductive device, comprising the following steps:

[0012] S1. Modulate the laser output waveform of the tunable laser driving source seed source through an arbitrary waveform generator, and achieve a high-energy, high-power, wide-band tunable high-frequency laser modulation signal through pre-modulation, multi-stage fiber amplification, and solid-state amplification;

[0013] S2, the tunable high-frequency laser modulation signal is input to the planar electrode type photoconductive device through an optical fiber or an optical waveguide, and the planar electrode type photoconductive device outputs a tunable radio frequency microwave electrical signal under the simultaneous action of the continuous laser pulse generated by the tunable laser driving source and the high voltage generated by the high-voltage power supply;

[0014] S3, the high-frequency microstrip line transmits and extracts the tunable radio frequency microwave electrical signal output by the planar electrode type photoconductive device;

[0015] S4. The antenna radiates the tunable RF microwave signal output by the output microstrip line through the RF interface at the tail end of the output microstrip line, thereby generating a tunable high-frequency microwave output.

[0016] Beneficial effects of the present invention:

[0017] The present invention utilizes the linear working mode of wide bandgap photoconductive semiconductor devices. Under the action of an external bias voltage, a tunable pulse cluster laser driving source is used to irradiate the wide bandgap photoconductive semiconductor devices, modulate and generate high-frequency electrical signals, and generate microwave signals through antenna radiation output, thereby realizing high-frequency microwave output with wide-range frequency tunability. At the same time, the present invention transmits the electrical signals modulated by the wide bandgap photoconductive semiconductor devices to the antenna through a microwave radio frequency transmission structure, thereby improving the photoelectric conversion efficiency of the system, and can realize narrow-spectrum microwave output with wide-range frequency tunability (0.5GHz to 50GHz), thereby realizing efficient extraction of wide-range tunable high-frequency microwaves. The present invention provides technical support for the development of a wide-range tunable high-power microwave integrated system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 It is a structural schematic diagram of the microwave radio frequency transmission structure of the present invention;

[0020] Figure 3 It is a schematic structural diagram of a planar electrode type photoconductive device of the present invention;

[0021] Figure 4 1 is a waveform diagram output in an embodiment of the present invention (from top to bottom are 0.5 GHz, 1 GHz, 4 GHz, 8 GHz, and 10 GHz microwave output experimental results).

[0022] 1. High voltage power supply 2. Microwave radio frequency transmission structure 3. Tunable laser drive source 4. Antenna 5. Planar electrode type photoconductive device 6. High frequency microstrip line 7. Input end microstrip line 8. Output end microstrip line 9. Planar electrode 10. Photoconductive semiconductor chip 11. Al 2 O 3 Insulating film. DETAILED DESCRIPTION

[0023] See also Figure 1-3 As shown:

[0024] The present invention provides a method for generating a large-range tunable high-frequency microwave based on a photoconductive device, comprising a device for generating a large-range tunable high-frequency microwave based on a photoconductive device, wherein the device comprises: a high-voltage power supply 1, a microwave radio frequency transmission structure 2, a tunable laser driving source 3 and an antenna 4, wherein the microwave radio frequency transmission structure 2 comprises a planar electrode type photoconductive device 5 and a high-frequency microstrip line 6, wherein the planar electrode type photoconductive device 5 is arranged on a substrate of the high-frequency microstrip line 6, wherein the high-frequency microstrip line 6 comprises an input end microstrip line 7 and an output end microstrip line 8, wherein two planar electrodes 9 of the planar electrode type photoconductive device 5 are respectively connected to the input end microstrip line 7 and the output end microstrip line 8, wherein a radio frequency interface is arranged at the tail end of the output end microstrip line 8; the high-voltage power supply 1 is connected to a planar electrode 9 of the planar electrode type photoconductive device 5 through the input end microstrip line 7, and the antenna 4 is connected to another planar electrode 9 of the planar electrode type photoconductive device 5 through the radio frequency interface and the output end microstrip line 8; and the output end of the tunable laser driving source 3 is connected to the planar electrode type photoconductive device 5 through an optical fiber or an optical waveguide.

[0025] The planar electrode type photoconductive device 5 comprises a planar electrode 9, a photoconductive semiconductor chip 10 and an Al 2 O 3 Insulating film 11, a pair of planar electrodes 9 are arranged on the surface of the photoconductive semiconductor wafer 10, and the remaining surface is Al 2 O 3 Insulating film 11; the photoconductive semiconductor chip 10 is a square or circular thin sheet of wide bandgap SiC material, the side length of the square is 1mm~50mm, the diameter of the circle is 1mm~50mm, and the thickness is 0.05mm~2mm; the planar electrodes 9 are all Ni / Ti / Au three-layer metal electrodes, and the three metal layers of Ni, Ti, and Au are arranged from bottom to top.

[0026] The material of the photoconductive semiconductor wafer 10 of the planar electrode type photoconductive device 5 is 4H-SiC or 6H-SiC.

[0027] The high voltage power supply 1 adopts a commercial 30kV high voltage continuous charging power supply to provide a bias voltage for the wide bandgap photoconductive device.

[0028] The tunable laser driving source 3 adopts a high-power tunable pulse cluster laser light source system based on acousto-optic / electro-optic modulation, which includes a pulse laser seed source, an acousto-optic modulator AOM, an electro-optic modulator EOM, a full polarization-maintaining fiber amplifier and a fiber cascade solid amplifier connected in sequence, and is used to generate repetition-frequency laser pulses with continuously adjustable pulse width and main frequency, and input the laser pulses to the planar electrode type photoconductive device 5 through an optical fiber or an optical waveguide, and modulate the photoconductive device to generate a high-frequency radio frequency signal. The output laser wavelength of the tunable laser driving source 3 is 1064nm, the envelope pulse width of the laser pulse cluster is 100ns, and the maximum pulse energy is 25mJ; the sub-pulse frequency in the envelope is tunable, the tunable range of the operating frequency is 0.5GHz-10GHz, and the maximum output peak power is on the order of hundreds of kW.

[0029] The antenna 4 is a flat broadband radiation horn that is impedance matched with the microwave radio frequency transmission structure 2 .

[0030] The substrate of the high-frequency microstrip line 6 is a high-speed PCB board, and the output end microstrip line 8 is matched and connected with the coaxial radio frequency interface.

[0031] The method for generating a large-range tunable high-frequency microwave comprises the following steps:

[0032] S1, modulate the laser output waveform of the 3 seed sources of the tunable laser driving source through an arbitrary waveform generator, and after pre-modulation, multi-stage fiber amplification, and solid amplification, realize a high-energy, high-power, wide-band tunable high-frequency laser modulation signal;

[0033] S2, the tunable high-frequency laser modulation signal is input to the planar electrode type photoconductive device 5 through an optical fiber or an optical waveguide, and the planar electrode type photoconductive device 5 outputs a tunable radio frequency microwave electrical signal under the simultaneous action of the continuous laser pulses generated by the tunable laser driving source 3 and the high voltage generated by the high-voltage power supply 1;

[0034] S3, the high-frequency microstrip line 6 transmits and extracts the tunable radio frequency microwave electrical signal output by the planar electrode type photoconductive device 5;

[0035] S4, the antenna 4 radiates the tunable radio frequency microwave signal output by the output end microstrip line 8 through the radio frequency interface at the tail end of the output end microstrip line 8, thereby generating a tunable high frequency microwave output.

[0036] This embodiment further verifies the large-range tunable high-frequency microwave generating device and method based on photoconductive devices of the present invention. The output waveform and spectrum distribution of the tunable high-frequency microwave generating device are shown in FIG. Figure 4 As shown by Figure 4 It can be seen that the tunable ultra-high repetition rate microwave generating device based on photoconductive devices of the present invention can output high-frequency microwaves in a wide range of tunable frequency, which proves the effectiveness of the present invention.

Claims

1. A method for generating a large-range tunable high-frequency microwave based on a photoconductive device, characterized in that: The invention comprises a large-range tunable high-frequency microwave generating device based on a photoconductive device, wherein the large-range tunable high-frequency microwave generating device based on a photoconductive device comprises: a high-voltage power supply, a microwave radio frequency transmission structure, a tunable laser driving source and an antenna, wherein the microwave radio frequency transmission structure comprises a planar electrode type photoconductive device and a high-frequency microstrip line, wherein the planar electrode type photoconductive device is arranged on a substrate of the high-frequency microstrip line, wherein the high-frequency microstrip line comprises an input end microstrip line and an output end microstrip line, wherein two planar electrodes of the planar electrode type photoconductive device are respectively connected to the input end microstrip line and the output end microstrip line, and a radio frequency interface is arranged at the tail end of the output end microstrip line; the high-voltage power supply is connected to a planar electrode of the planar electrode type photoconductive device through the input end microstrip line, and the antenna is connected to another planar electrode of the planar electrode type photoconductive device through the radio frequency interface and the output end microstrip line; and the output end of the tunable laser driving source is connected to the planar electrode type photoconductive device; The method for generating a wide range of tunable high-frequency microwaves comprises the following steps: S1. Modulate the laser output waveform of the tunable laser driving source seed source through an arbitrary waveform generator, and achieve a high-energy, high-power, wide-band tunable high-frequency laser modulation signal through pre-modulation, multi-stage fiber amplification, and solid-state amplification; S2, a tunable high-frequency laser modulation signal is input to a planar electrode type photoconductive device, and the planar electrode type photoconductive device outputs a tunable radio frequency microwave electrical signal under the simultaneous action of a continuous laser pulse generated by a tunable laser driving source and a high voltage generated by a high-voltage power supply; S3, the high-frequency microstrip line transmits and extracts the tunable radio frequency microwave electrical signal output by the planar electrode type photoconductive device; S4. The antenna radiates the tunable RF microwave signal output by the output microstrip line through the RF interface at the tail end of the output microstrip line, thereby generating a tunable high-frequency microwave output.

2. The method for generating a large-range tunable high-frequency microwave based on a photoconductive device according to claim 1, characterized in that: The planar electrode type photoconductive device comprises a photoconductive semiconductor chip, a planar electrode and a transparent insulating film. A pair of planar electrodes are arranged side by side on the surface of the photoconductive semiconductor chip, and the remaining surface is a transparent insulating film. The planar electrodes are all Ni / Ti / Au three-layer metal electrodes, and the three metal layers of Ni, Ti and Au are arranged from bottom to top.

3. The method for generating a large-range tunable high-frequency microwave based on a photoconductive device according to claim 2, characterized in that: The photoconductive semiconductor wafer material of the planar electrode type photoconductive device is 4H-SiC or 6H-SiC.

4. The method for generating a large-range tunable high-frequency microwave based on a photoconductive device according to claim 1, characterized in that: The substrate of the high-frequency microstrip line is a high-speed plate, and the output end microstrip line is matched and connected with a coaxial radio frequency interface.

5. The method for generating a large-range tunable high-frequency microwave based on a photoconductive device according to claim 1, characterized in that: The tunable laser driving source adopts a high-power tunable pulse cluster laser light source system based on acousto-optic / electro-optic modulation, which includes a pulse laser seed source, an acousto-optic modulator, an electro-optic modulator, a fiber amplifier and a solid amplifier connected in sequence.

6. The method for generating a large-range tunable high-frequency microwave based on a photoconductive device according to claim 1, characterized in that: The antenna is a flat broadband radiating horn.

7. A widely tunable high-frequency microwave generator based on a photoconductive device, characterized in that: The invention comprises a high-voltage power supply, a microwave radio frequency transmission structure, a tunable laser driving source and an antenna. The microwave radio frequency transmission structure comprises a planar electrode type photoconductive device and a high-frequency microstrip line. The planar electrode type photoconductive device is arranged on a substrate of the high-frequency microstrip line. The high-frequency microstrip line comprises an input end microstrip line and an output end microstrip line. Two planar electrodes of the planar electrode type photoconductive device are respectively connected to the input end microstrip line and the output end microstrip line. A radio frequency interface is arranged at the tail end of the output end microstrip line. The high-voltage power supply is connected to a planar electrode of the planar electrode type photoconductive device through the input end microstrip line. The antenna is connected to another planar electrode of the planar electrode type photoconductive device through the radio frequency interface and the output end microstrip line. The output end of the tunable laser driving source is connected to the planar electrode type photoconductive device through an optical fiber or an optical waveguide.

8. The large-range tunable high-frequency microwave generating device based on a photoconductive device according to claim 7, characterized in that: The planar electrode type photoconductive device comprises a photoconductive semiconductor chip, a planar electrode and a transparent insulating film. A pair of planar electrodes are arranged side by side on the surface of the photoconductive semiconductor chip, and the remaining surface is a transparent insulating film. The photoconductive semiconductor chip material is 4H-SiC or 6H-SiC, and the planar electrodes are all Ni / Ti / Au three-layer metal electrodes, wherein the three metal layers of Ni, Ti and Au are arranged from bottom to top.

9. The large-range tunable high-frequency microwave generating device based on a photoconductive device according to claim 7, characterized in that: The substrate of the high-frequency microstrip line is a high-speed plate, and the output end microstrip line is matched and connected with a coaxial radio frequency interface.

10. The large-range tunable high-frequency microwave generating device based on a photoconductive device according to claim 7, characterized in that: The tunable laser driving source adopts a high-power tunable pulse cluster laser light source system based on acousto-optic / electro-optic modulation, which includes a pulse laser seed source, an acousto-optic modulator, an electro-optic modulator, a fiber amplifier and a solid amplifier connected in sequence.

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