Photoconductive switch link assembly for realizing output microwave frequency band expansion

Abstract

The embodiment of the invention provides a photoconductive switch link assembly, which comprises a photoconductive switch, a high-voltage conductor, a connector, a grounding conductor, a capacitor and a radio frequency connector, and is characterized in that the photoconductive switch, the high-voltage conductor, the connector, the grounding conductor, the capacitor and the radio frequency connector are coaxially connected; the high-voltage conductor, the grounding conductor, the capacitor and the radio frequency connector are stacked, the capacitor is located between the high-voltage conductor and the grounding conductor, and the grounding conductor is located between the capacitor and the radio frequency connector; an accommodating space is arranged in the capacitor, and the photoconductive switch is accommodated in the accommodating space; the input end of the photoconductive switch is connected with the high-voltage conductor, and the output end of the photoconductive switch is connected with the connector and is connected with the radio frequency connector through the connector; a containing cavity is formed in the side, facing the capacitor, of the grounding conductor, and the connecting body is located in the containing cavity. The whole structure of the link is high in integration level, compact in structure, small in external electromagnetic interference in the transmission process of current / voltage, and high in fidelity.

Description

Technical Field

[0001] The present application relates to the field of high-power microwave technology, and in particular to a photoconductive switch link component for achieving output microwave frequency band expansion. Background Art

[0002] The photoconductive switch consists of a semiconductor substrate and two electrodes. It has the characteristics of fast response, small jitter, and photoelectric isolation. Its working principle is: bias voltage is applied through the electrodes, and intrinsic or extrinsic light is used to irradiate the semiconductor substrate. The semiconductor substrate generates photogenerated carriers under the action of the laser. The photogenerated carriers move in a directional manner under the action of the bias voltage to form a current, which causes the circuit where the photoconductive switch is located to be turned on. The greater the concentration of photogenerated carriers in the semiconductor substrate, the greater its conductivity. According to the different working modes of the photoconductive switch, when a photon excites a carrier, the photoconductive switch works in a linear mode. The photoconductive switch can be regarded as a light-controlled resistor, and the resistance change of the photoconductive switch is proportional to the laser irradiation power. Changing the laser irradiation parameters (power, pulse width, modulation frequency, repetition rate) can change the output electrical parameters of the circuit where the photoconductive switch is located. The output waveform of the photoconductive switch has the characteristics of adjustable parameters such as frequency. The photoconductive switch has broad application prospects in the fields of high-power microwaves with adjustable frequency and ultrafast electronic response.

[0003] The photoconductive switch has the ability to output an electrical waveform that is consistent with the optical waveform. For optical waveforms of different frequencies, the frequency response capability of the photoconductive switch output electrical waveform is affected by many factors. The frequency response capability is not only related to the characteristics of the photoconductive switch itself, but the increase in carrier lifetime will cause the frequency response characteristics of the photoconductive switch to deteriorate. The smaller the interstage capacitance of the photoconductive switch, the higher the cutoff frequency, and the better the frequency response characteristics. In addition, for the photocurrent extraction output generated by the photoconductive switch, the corresponding circuit structure needs to be designed to match it. The frequency response capability of the photoconductive microwave generation system is also related to the frequency response capability of the matching circuit.

[0004] According to the different distribution of electrodes, photoconductive switches can be divided into two structures, namely planar photoconductive switches and vertical photoconductive switches. The electrodes of planar photoconductive switches are distributed on the same side of the semiconductor substrate, and the inter-stage capacitance is small. The combination of planar photoconductive switches and high-frequency microstrip transmission lines can achieve a system microwave output of 0.5-10 GHz. The patent name is "Large-range tunable high-frequency microwave generation device and method based on photoconductive devices (publication number: CN114927514A)", which reports a tunable microwave generation device based on a planar photoconductive switch. The microstrip line has a compact structure and a small volume and weight, but the signal transmitted by the microstrip line will introduce insertion loss when it is connected to the external photoconductive device. The impedance mismatch at the connection between the microstrip line and the RF connector will introduce return loss. The limitation of planar photoconductive switches for microwave generation is that their breakdown field strength is low, surface flashover is prone to occur, and the output power is low, which limits its further promotion in high-power microwave generation. The vertical photoconductive switch is distributed on both sides of the semiconductor substrate. The vertical photoconductive switch has strong voltage resistance and high output power. Based on the combination of vertical photoconductive switch and CVR, the National University of Defense Technology extracts the current / voltage on the photoconductive switch through CVR to achieve the output of the system at 1GHz. [L Wang et al., Vertical SiC photoconductive switch with axialoptical internal reflection trap, 2022, pp. 5028–5034. (Vertical SiC photoconductive switch with axial optical internal reflection trap, IEEE Transactions on Electron Devices, 2022, pp. 5028-5034)]. The CVR circuit can achieve higher power microwave output by reducing the circuit load, but because the load is reduced, the circuit does not meet the standard impedance matching circuit. The existence of circuit stray parameters such as stray inductance and capacitance will cause the generation of oscillation in the circuit, affecting the linear output and frequency response characteristics of the photoconductive switch.

[0005] Improving the frequency response capability of vertical photoconductive switches mainly includes: First, starting from the characteristics of semiconductor substrates: reducing carrier lifetime by controlling doping concentration; reducing inter-stage capacitance by increasing electrode spacing or reducing electrode area. Second, designing a suitable RF extraction circuit to reduce circuit stray parameters. Currently, there is a lack of RF extraction circuits suitable for achieving frequency band expansion of vertical photoconductive switches. Therefore, it is necessary to design a new circuit structure to extract the photocurrent generated by the photoconductive switch, reduce the influence of stray parameters on the high-frequency characteristics of the circuit output, and achieve the frequency band expansion of the photoconductive switch output frequency-adjustable microwaves. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a photoconductive switch coaxial link structure for realizing the expansion of the output microwave frequency band. The structure is compact, the shielding effect is good, the interference from the outside world is small, the transmission frequency band is widened, and the stray parameters are small, which improves the current problems of limited response frequency and small response frequency band of photoconductive switches.

[0007] The present application provides a photoconductive switch link assembly for realizing output microwave frequency band expansion, the photoconductive switch link assembly comprising a photoconductive switch, a high-voltage conductor, a connector, a ground conductor, a capacitor and a radio frequency connector, wherein the photoconductive switch, the high-voltage conductor, the connector, the ground conductor, the capacitor and the radio frequency connector are coaxially connected; The high-voltage conductor, the grounding conductor, the capacitor and the radio frequency connector are stacked, the capacitor is located between the high-voltage conductor and the grounding conductor, and the grounding conductor is located between the capacitor and the radio frequency connector; A receiving space is provided inside the capacitor, and the photoconductive switch is received in the receiving space; The input end of the photoconductive switch is connected to the high voltage conductor, the output end of the photoconductive switch is connected to the connector, and is connected to the radio frequency connector through the connector; A receiving cavity is provided on a side of the grounding conductor facing the capacitor, and the connecting body is located in the receiving cavity.

[0008] Optionally, the input end and the output end are located on opposite sides of the photoconductive switch.

[0009] Optionally, a central through hole is provided on the high-voltage conductor, and the input end of the photoconductive switch extends out through the central through hole and is fixedly connected to the high-voltage conductor via a fastener.

[0010] Optionally, the connector includes an input portion and an output portion, and the input portion and the output portion are stacked; The input part is connected to the output end of the photoconductive switch, and the output part is connected to the radio frequency connector.

[0011] Optionally, the input portion is cylindrical, the output portion is a portion of a cone, and the radius of an end of the output portion connected to the input portion is greater than the radius of an end of the output portion away from the input portion.

[0012] Optionally, the input portion is located in the receiving space.

[0013] Optionally, a through hole is provided at the bottom of the receiving cavity, and the connecting end of the radio frequency connector is connected to the connecting body through the through hole.

[0014] Optionally, the capacitor is a ring capacitor.

[0015] Optionally, the capacitor includes a plurality of sub-capacitors, and the plurality of sub-capacitors form a ring shape with a receiving space in the middle.

[0016] Optionally, centers of the sub-capacitors are located on the same circle.

[0017] Compared with the prior art, the optical switch coaxial link structure for realizing output microwave frequency band extension provided in the embodiment of the present application can achieve the following technical effects: 1. The high-voltage conductor, grounding conductor, connector, photoconductive switch and radio frequency interface in the invented link are all coaxial structures, and the current / voltage is less affected by external electromagnetic interference during transmission, and the fidelity is high.

[0018] 2. The cavity in the ground conductor of the invented link is a conical cavity containing the connection between the output end of the photoconductive switch and the input end of the radio frequency interface. The overall structure of the link is highly integrated and compact.

[0019] 3. The connector structure in the invented link is a combination of a cylinder and a partial cone, which realizes the coupling of the photoconductive switch and the radio frequency connector and the impedance matching of the subsequent measurement circuit.

[0020] 4. The coaxial structure of the invented link can improve the power capacity of the overall input electrical pulse of the link.

[0021] 5. The invented link structure is compact, the influence of stray capacitance and stray inductance on the circuit is reduced, and the expansion of the coaxial link transmission signal frequency band is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the structure of a photoconductive switch link assembly provided in an embodiment of the present application; Figure 2 for Figure 1 An exploded view of the optical switch link assembly shown in; Figure 3a for Figure 2 A front view of the photoconductive switch shown in; Figure 3b for Figure 2 A top view of the photoconductive switch shown in FIG.

[0023] Figure 4a for Figure 2 A top view of the high voltage conductor shown in; Figure 4b for Figure 4a Section along AA'; Figure 5a for Figure 2 A front view of the connector shown in; Figure 5b Figure 2 A top view of the connector shown in ; Figure 5c for Figure 5b Section along AA'; Figure 6a for Figure 2 A front view of the ground conductor shown in; Figure 6b for Figure 6a Section along AA'; Figure 6c for Figure 2 A top view of the ground conductor shown in ; Figure 7a for Figure 2 A front view of a sub-capacitor shown in; Figure 7b for Figure 2 A top view of the sub-capacitor shown in FIG. Figure 8a for Figure 2 A front view of the RF connector shown in; Figure 8b for Figure 2 A top view of the RF connector shown in ; Figure 8c for Figure 2 A bottom view of the RF connector shown in ; Fig. 9 A schematic diagram of the structure of another optical switch link assembly provided in an embodiment of the present application; Fig.10 for Fig. 9 An exploded view of the optical switch link assembly shown in; Fig.11a for Fig.10 A front view of the capacitor shown in; Fig.11b for Fig.10 A top view of the capacitor shown in FIG. Fig.12 is a waveform diagram of the DC bias voltage of the link component; Fig.13 It is the waveform diagram of the laser signal at different frequencies; Fig.14 It is a waveform diagram of the response electrical signal corresponding to the laser frequency when triggered by laser signals of different frequencies; Fig.15 for Fig.14 The spectrum diagram corresponding to the response electrical waveform diagram at different frequencies.

[0024] Among them, 0, photoconductive switch; 1, high-voltage conductor; 2, connector; 3, grounding conductor; 4, capacitor; 41, sub-capacitor; 5, RF connector; 6, capacitor. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0026] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0027] The specific implementation of the present invention is further described below in conjunction with the drawings and examples.

[0028] Please also see Figure 1 and Figure 2 , Figure 1 A schematic diagram of the structure of a photoconductive switch link assembly provided in an embodiment of the present application, Figure 2 for Figure 1 An exploded view of the photoconductive switch link assembly is shown in FIG. Figure 1 and Figure 2 As shown, the optical switch link component of the present application includes an optical switch 0, a high-voltage conductor 1, a connector 2, a grounding conductor 3, a capacitor 4, and a radio frequency connector 5. The optical switch 0, the high-voltage conductor 1, the connector 2, the grounding conductor 3, the capacitor 4, and the radio frequency connector 5 are coaxially connected.

[0029] Among them, the high-voltage conductor 1, the grounding conductor 3, the capacitor 4 and the radio frequency connector 5 are stacked, the capacitor 4 is located between the high-voltage conductor 1 and the grounding conductor 3, the grounding conductor 3 is located between the capacitor 4 and the radio frequency connector 5, a receiving space is provided inside the capacitor 4, the photoconductive switch 0 is accommodated in the receiving space inside the capacitor 4, a receiving cavity is provided on the side of the grounding conductor 3 facing the capacitor 4, and a part of the connector 2 is located in the receiving cavity of the grounding conductor 3.

[0030] The RF connector 5 is connected and fixed to the ground conductor 3 by screws, one end of the capacitor 4 is connected and fixed to the high-voltage conductor 1 by screws, and the other end of the capacitor 4 is connected and fixed to the ground conductor 3 by screws.

[0031] Please also see Figure 3a and Figure 3b , Figure 3a for Figure 2 A front view of the photoconductive switch shown in FIG. Figure 3b for Figure 2 A top view of the photoconductive switch shown in FIG. Figure 3a and Figure 3b As shown, the end of the photoconductive switch 0 connected to the high-voltage conductor 1 is defined as the input end, and the end connected to the connector 2 is defined as the output end. The input end and the output end of the photoconductive switch 0 are located on opposite sides of the photoconductive switch 0. The input end of the photoconductive switch 0 is connected to the high-voltage conductor 1, and the input end of the photoconductive switch 0 extends from the high-voltage conductor 1. The end of the output end thereof can be adapted to a nut. The photoconductive switch 0 is connected to the high-voltage conductor 1 through a nut to fasten the photoconductive switch 0 to the high-voltage conductor 1. The output end of the photoconductive switch 0 is connected to the connector 3, and is connected to the radio frequency connector 5 through the connector 3.

[0032] The structure of the photoconductive switch 0 can refer to the photoconductive switch in the patent titled "An optical structure for improving the photoelectric conversion efficiency of a silicon carbide photoconductive switch (publication number: CN111739953A)", such as Figure 3a As shown. The packaging method of the photoconductive switch 0 refers to the patent name "Megawatt-class photoconductive semiconductor device and electrode connection and insulation packaging method (publication number: CN111584434A)". The diameter of the screw at the input end of the external photoconductive switch 0 of the insulation package is D001 and the length is H001. The diameter of the screw at the output end of the external photoconductive switch 0 of the insulation package is D002 and the length is H002. The photoconductive switch 0 after insulation packaging is L001 long, W001 wide and H003 high.

[0033] Please also see Figure 4a and Figure 4b , Figure 4a for Figure 2 A top view of the high voltage conductor shown in, Figure 4b for Figure 4a The cross-section along AA'. Figure 4a and Figure 4bAs shown, a central through hole is provided on the high-voltage conductor 1, which is a metal ring structure with a through hole in the center. The input end of the photoconductive switch 0 extends from one side of the high-voltage conductor to the other side through the central through hole, and is fixedly connected to the high-voltage conductor 1 through a fastener. Among them, the high-voltage conductor 1 is made of metal material, the high-voltage conductor 1 is a coaxial structure, the thickness of the high-voltage conductor 1 is H101, the outer diameter of the high-voltage conductor 1 is D101, the diameter of the central through hole of the high-voltage conductor 1 is D102, the edge of the high-voltage conductor 1 is chamfered at 45°, the chamfer radius is R101, and the central through hole of the high-voltage conductor 1 is chamfered at 45°, and the chamfer length is C101. Edge through holes are provided at the edge position of the high-voltage conductor 1, and the edge through holes are evenly distributed around the high-voltage conductor 1. The distance between the center of the edge through hole and the center of the high-voltage conductor 1 is R102, the number of through holes is N, the diameter is D103, the N through holes are chamfered at 45°, and the chamfer length is C102.

[0034] Please also see Figure 5a , Figure 5b and Figure 5c , Figure 5a for Figure 2 A front view of the connector shown in FIG. Figure 5b Figure 2 A top view of the connector shown in FIG. Figure 5c for Figure 5b The cross-section along AA'. Figure 5a , Figure 5b and Figure 5c As shown, the connector 2 includes an input portion and an output portion, which are stacked. The connector 2 is located in the accommodating cavity of the grounding conductor 3 , wherein the input portion is connected to the output end of the photoconductive switch 0 , and the output portion is connected to the radio frequency connector 5 .

[0035] In a possible embodiment, the connector 2 is made of metal material, the input portion of the connector 2 is cylindrical, the diameter of the cylinder is D201, the height is H201, a threaded hole is provided inside the cylinder, and correspondingly, the output end of the optical switch is provided with a thread, the threaded hole of the cylinder is adapted and connected to the thread of the output end of the optical switch, and the length of the threaded hole of the cylinder is the same as the length of the cylinder, which is H202. The output part of the connector 2 is a part of a cone, and the radius of the end where the output part is connected to the input part is greater than the radius of the end where the output part is away from the input part, that is, the diameter of the connecting part between the cone and the cylinder is the same as the diameter of the cylinder, which is D202, and the diameter of the circle where the cone is away from the cylinder is D203, which is smaller than D202. The connecting part between the cone and the cylinder is chamfered at 135°, and the chamfer radius is R201. The height of the cone is H203, and a threaded hole is provided inside the cone, and the length of the threaded hole is the same as the length of the cone, which is H204. Correspondingly, the designer has threads on the connecting end of the RF connector 5 connected to the output part, and the threaded hole of the cone is adapted and connected to the threads of the connecting end of the RF connector 5. The edge of the connecting end of the cylinder and the photoconductive switch 0 is chamfered at 45°, and the chamfer length is C201. The edge of the connecting end of the cone and the RF connector 5 is chamfered at 135°, and the chamfer radius is R202.

[0036] Please also see Figure 6a , Figure 6b and Figure 6c , Figure 6a for Figure 2 A front view of the ground conductor shown in Figure 6b for Figure 6a Sectional view along AA', Figure 6c for Figure 2 A top view of the ground conductor shown in . Figure 6a , Figure 6b and Figure 6c The grounding conductor 3 is made of metal material and has a coaxial structure. The grounding conductor 3 is composed of cylinders with a diameter of D301 and a diameter of D302. The cylinder with a diameter of D301 is the same as the outer diameter D101 of the high-voltage conductor 1. The length of the cylinder with a diameter of D301 is H301. The edge through holes are evenly distributed around the cylinder with a diameter of D302 of the grounding conductor 3. The center distance R301 of the edge through hole of the grounding conductor 3 from the center of the cylinder with a diameter of D301 is equal to the distance R102 between the center of the edge through hole of the high-voltage conductor 1 and the center of the high-voltage conductor 1. The number of through holes is M, which is equal to the number N of edge through holes of the high-voltage conductor 1. The diameter is D303, which is equal to the diameter D102 of the edge through hole of the high-voltage conductor 1. The length of the cylinder with a diameter of D302 is H302.

[0037] There is a conical cavity in the center of the grounding conductor composed of cylinders with diameters D301 and D302. The cavity is the accommodating cavity set on the side of the grounding conductor 3 facing the capacitor 4. The conical cavity penetrates the cylinder with diameter D301. The conical cavity is a part of the cylinder with diameter D302. The diameter of the circle of the conical cavity close to the cylinder with diameter D301 is D304, the diameter of the circle of the conical cavity close to the cylinder with diameter D302 is D305, and the length of the conical cavity is H303. The bottom of the accommodating cavity, that is, the bottom of the conical cavity, is provided with a through hole, which penetrates the cylinder with diameter D302. The diameter of the through hole is the same as the inner conductor diameter D501 outside the insulating material of the input end of the RF connector 5, which is D306, and the length of the through hole is H304. There are 4 threaded holes around the through hole, and the positions of the threaded holes correspond to and match the positions of the through holes at the connection end of the RF connector 5. Screws are used to connect the ground conductor 3 and the outer conductor of the RF connector 5. The connection between the cylinder with a diameter of D301, the cylinder with a diameter of D302 and the conical cavity is chamfered at 135°, with a chamfer radius of R302, and the edge of the cylinder with a diameter of D302 is chamfered at 45°, with a chamfer radius of R303.

[0038] Please also see Figure 7a and Figure 7b , Figure 7a for Figure 2 The front view of the sub-capacitor is shown in Figure 7b for Figure 2 The top view of the sub-capacitor is shown in FIG. Figure 7a and Figure 7b As shown in , in the embodiment of the present application, the capacitor 4 includes a plurality of sub-capacitors 41, and the plurality of sub-capacitors 41 are surrounded by a ring with a receiving space in the middle, and the centers of the sub-capacitors 41 are located on the same circumference. Among them, the sub-capacitor 4 is a high-voltage capacitor with a withstand voltage of 50 kV and a capacitance of C. The sub-capacitor 41 is a cylindrical structure with threaded holes at the centers of both ends. The outer diameter of the sub-capacitor 41 is D401, and the length of the sub-capacitor 41 is H401. The screws connect and fasten the through holes around the high-voltage conductor 1 to the threaded holes at one end of the sub-capacitor 41. The screws connect and fasten the through holes around the grounding conductor 3 to the threaded holes at the other end of the sub-capacitor 41.

[0039] Please also see Figure 8a , Figure 8b and Figure 8c , Figure 8a for Figure 2 Front view of the RF connector shown in, Figure 8b for Figure 2 A top view of the RF connector shown in Figure 8c for Figure 2 Bottom view of the RF connector shown in . Figure 8a , Figure 8b and Figure 8c As shown, the RF connector 5 is a coaxial component, and the RF connector 5 consists of three parts: an inner conductor, an insulating material, and an outer conductor. The inner conductor and the outer conductor are made of metal materials. The inner conductor outside the insulating material at the input end of the RF connector 5 has a diameter of D501 and a length of H501. The insulating material at the input end of the RF connector 5 has a diameter of D502 and a length of H502.

[0040] See also Fig. 9 , Fig.10 , Fig.11a and Fig.11b , Fig. 9 A schematic diagram of the structure of another optical switch link assembly provided in an embodiment of the present application, Fig.10 for Fig. 9 An exploded view of the optical switch link assembly shown in FIG. Fig.11a for Fig.10 Front view of the capacitor shown in, Fig.11b for Fig.10 A top view of the capacitor shown in . Fig. 9 , Fig.10 , Fig.11a and Fig.11b As shown, another optical switch link component provided by the embodiment of the present application is Figure 1 and Figure 2 The structures of the optical switch link components shown are basically the same, except that Figures 9 to 11b In the optical switch link assembly shown, capacitor 6 is a ring capacitor, which is a high-voltage capacitor with a withstand voltage of 50 kV, a capacitance of C, an outer diameter of capacitor 6 of D601, an inner diameter of capacitor 6 of D602, and a length of capacitor 6 of H601. The through hole around the high-voltage conductor is connected and fastened with a threaded hole at one end of capacitor 6 by a screw. The through hole around the grounding conductor is connected and fastened with a threaded hole at the other end of capacitor 6 by a screw.

[0041] Among them, the inner diameter D602 of the capacitor 6, the length L001 of the photoconductive switch, and the width W001 of the photoconductive switch must meet the following requirements: ; The distance L between the grounding conductor and the high-voltage conductor, and the length H401 of the capacitor satisfy: L=H601; the length of the through hole of the cylinder with a diameter of D302 is H304, the length of the insulating material at the input end of the RF connector is H502, the length of the screw at the input end of the insulating package external photoconductive switch is H001, the length of the screw at the output end of the insulating package external photoconductive switch is H002, the thickness of the high-voltage conductor is H101, the height of the photoconductive switch after insulation packaging is H003, the length of the capacitor is H601, and the length of the conical cavity of the grounding conductor is H303; The length of the connector is H201+H202, the length of the screws at the input end of the insulating package external photoconductive switch is H001, the length of the screws at the output end of the insulating package external photoconductive switch is H002, the length of the inner conductor outside the insulating material at the input end of the RF connector is H501, and the length of the insulating material at the input end of the RF connector is H502. The following requirements are met: H001>(H502-H304)+(H501+H002)-(H201+H202)+(H003+H001)-(H601+H303)>H101.

[0042] The optical switch link assembly provided in the embodiment of the present application has low external electromagnetic interference during the transmission of current / voltage, high fidelity, high integration of the overall link structure, compact structure, capable of achieving impedance matching of subsequent measurement circuits, improving the power capacity of the overall input electrical pulse of the link, reducing the influence of stray capacitance and stray inductance on the circuit, and achieving the expansion of the coaxial link transmission signal frequency band. Figures 12 to 15 , it can be expected that it has good performance. Among them, Fig.12 is the DC bias voltage waveform of the link component, Fig.13 The waveform diagram of the laser signal at different frequencies (from top to bottom, from left to right: 0.2 GHz, 0.4 GHz, 0.8 GHz, 1.2 GHz, 1.6 GHz, 2 GHz), Fig.14 The waveform diagram of the response electrical signal corresponding to the laser frequency when triggered by laser signals of different frequencies (from top to bottom, from left to right: 0.2 GHz, 0.4 GHz, 0.8 GHz, 1.2 GHz, 1.6 GHz, 2 GHz). Fig.15 for Fig.14 The frequency spectrum corresponding to the response electrical waveform at different frequencies (from top to bottom, from left to right: 0.2 GHz, 0.4 GHz, 0.8 GHz, 1.2 GHz, 1.6 GHz, 2 GHz).

[0043] In one possible embodiment, corresponding to Figures 12 to 15 The waveform diagram of Figure 1 and Figure 2 Taking the photoconductive switch link component shown in the figure as an example, a specific design dimension of a photoconductive switch link component for realizing output microwave frequency band expansion (0.2-2 GHz) is given: D001=8 mm, H001=9 mm, D002=6 mm, H002=9 mm, H003=8 mm, L001=25 mm, W001=25mm; D101=95 mm, D102=8 mm, D103=6 mm, H101=5 mm, R101=1 mm, R102=40 mm, C101=0.5 mm, C102=0.5 mm, N=6; D201=20 mm, D202=20 mm, D203=10 mm, H201=5 mm, H202=5 mm, H203=5 mm, H204=5mm, C201=0.5 mm, R201=3 mm, R202=3 mm; D301=95 mm, D302=65 mm, D303=6 mm, D304=45 mm, D305=5 mm, D306=5 mm, H301=5mm, H302=20 mm, H303=12 mm, H304=13 mm, R301=40 mm, R302=1 mm, R303=4 mm, R304=1 mm, M=6; D401=35 mm, H401=25 mm; D501=5 ​​mm, D502=10 mm, H501=5 ​​mm, H502=17 mm.

[0044] The above dimensions are only examples of possible implementations and are not limited thereto. It is understandable that in other implementations, in order to achieve output microwave frequency band expansion of other frequencies, one or more parameters may be adjusted accordingly, and the present invention is not limited thereto.

[0045] For the convenience of description, the conditions satisfied by the structural parameters of the above designs are introduced here: The diameter D102 of the central through hole of the high-voltage conductor and the diameter D001 of the screw at the input end of the photoconductive switch outside the insulation package meet the following conditions: D102>D001; the outer diameter D101 of the high-voltage conductor, the diameter D102 of the central through hole of the high-voltage conductor, the diameter D103 of the edge through hole of the high-voltage conductor, the distance R102 between the center of the edge through hole and the center of the high-voltage conductor, the outer diameter D401 of the capacitor, the length L001 of the photoconductive switch, and the width W001 of the photoconductive switch must meet the following conditions: D101 / 2>R102+D103 / 2, ; The thickness H101 of the high-voltage conductor and the length H001 of the screw at the input end of the optical switch satisfy: H001>H101>0; The number of through holes of the high-voltage conductor N, the distance between the center of the through hole at the edge of the high-voltage conductor and the center of the high-voltage conductor R102, and the outer diameter of the capacitor D401 satisfy: ; The chamfer radius R101 of the edge of the high-voltage conductor and the chamfer radius R103 of the N edge through holes of the high-voltage conductor satisfy: R101>0, R103>0.

[0046] The diameter D201 of the cylinder at the input end of the connector and the diameter D002 of the thread at the output end of the photoconductive switch outside the insulating package satisfy: D201>D002; the diameter D201 of the circle of the cone at the output end of the connector away from the cylinder and the diameter D501 of the inner conductor outside the insulating material at the input end of the RF connector satisfy: D201>D501; the diameter D202 of the connecting part between the cone and the cylinder and the diameter D201 of the cylinder satisfy: D202=D202; the chamfer radius R201 of the connecting part between the cone and the cylinder, the chamfer radius R202 of the edge of the connecting end of the cylinder and the photoconductive switch, and the chamfer radius R203 of the edge of the inner conductor of the cone close to the insulating material outside the input end of the RF connector satisfy: R201>0, R202>0, R203>0.

[0047] The cylinder with a grounding conductor diameter of D301 and the outer diameter of the high-voltage conductor D101 satisfy: D301=D101; the distance R301 from the center of the grounding conductor edge through hole to the center of the cylinder with a diameter of D301 and the distance R102 from the center of the edge through hole of the high-voltage conductor to the center of the high-voltage conductor satisfy: R301=R102; the number of edge through holes of the grounding conductor M and the number of edge through holes of the high-voltage conductor N satisfy: N=M, the diameter D303 of the edge through hole of the grounding conductor and the diameter D102 of the edge through hole of the high-voltage conductor satisfy: D303=D 102; for a cylinder with a grounding conductor diameter of D302, the distance R301 from the center of the grounding conductor edge through hole to the center of the cylinder with a diameter of D301, and the diameter D303 of the grounding conductor edge through hole satisfy: R301-D303 / 2>D302 / 2; the diameter D304 of the circle of the conical cavity close to the cylinder with a diameter of D301, the distance R301 from the center of the grounding conductor edge through hole to the center of the cylinder with a diameter of D301, and the diameter D303 of the grounding conductor edge through hole satisfy: R301-D303 / 2>D304 / 2. The diameter D305 of the circle of the conical cavity close to the cylinder with a diameter of D302 and the diameter D306 of the through hole at one end of the cylinder with a diameter of D302 connected to the RF connector satisfy: D305=D306; the length H303 of the conical cavity, the length H304 of the through hole of the cylinder with a diameter of D302 connected to the RF connector, the length H301 of the cylinder with a diameter of D301, and the length H302 of the cylinder with a diameter of D302 satisfy: H301+H302-H304=H303; the diameter D303 of the through hole of the cylinder with a diameter of D302 The diameter D501 of the insulating material at the input end of the RF connector satisfies: D306=D501; the through-hole length H304 of the cylinder with a diameter of D302 and the insulating material length H502 of the input end of the RF connector satisfy: H502>H304; the edge chamfer radius R302 of the cylinder with a diameter of D301, the chamfer radius R303 at the connection between the cylinder with a diameter of D301, the cylinder with a diameter of D302 and the cone cavity, and the edge chamfer radius R304 of the cylinder with a diameter of D302 satisfy: R302>0, R303>0, R304>0. The distance L between the grounding conductor and the high-voltage conductor and the length H401 of the capacitor satisfy: L=H401.

[0048] The length of the through hole of the cylinder with a diameter of D302 is H304, the length of the insulating material at the input end of the RF connector is H502, the length of the screw at the input end of the insulating package external photoconductive switch is H001, the length of the screw at the output end of the insulating package external photoconductive switch is H002, the thickness of the high-voltage conductor is H101, the height of the photoconductive switch after insulation packaging is H003, the capacitor length is H401, and the length of the conical cavity of the grounding conductor is H303; the length of the connector is H201+H202, the length of the screw at the input end of the insulating package external photoconductive switch is H001, the length of the screw at the output end of the insulating package external photoconductive switch is H002, the length of the inner conductor outside the insulating material at the input end of the RF connector is H501, and the length of the insulating material at the input end of the RF connector is H502. The following requirements are met: H001>(H502-H304)+(H501+H002)-(H201+H202)+(H003+H001)-(H401+H303)>H101.

[0049] The working process of the present invention is: by Figure 1 and Figure 2 Taking the photoconductive switch link assembly shown in the figure as an example, the bias voltage is loaded on the high-voltage conductor, and the high-voltage conductor, the capacitor input end, and the photoconductive switch input end are of equal potential. The bias voltage charges N parallel sub-capacitors, and the N parallel sub-capacitors act as a DC power supply. The laser irradiates the photoconductive switch substrate through the screws of the photoconductive switch input end outside the insulating package, and the photoconductive switch substrate generates photogenerated carriers. The photogenerated carriers move in a directional manner under the action of the DC bias voltage to form a current. The conductivity of the photoconductive switch increases rapidly, and the photoconductive switch is closed. The current flows through the photoconductive switch, the output end of the photoconductive switch, the connector, and finally output by the RF connector. The capacitor output end and the outer conductor of the RF connector are grounded through the grounding conductor.

[0050] Compared with the prior art, the present invention can achieve the following technical effects: 1. The high-voltage conductor, grounding conductor, connector, photoconductive switch and radio frequency interface in the invented link are all coaxial structures, and the current / voltage is less affected by external electromagnetic interference during transmission, and the fidelity is high.

[0051] 2. The cavity in the ground conductor of the invented link is a conical cavity containing the connection between the output end of the photoconductive switch and the input end of the radio frequency interface. The overall structure of the link is highly integrated and compact.

[0052] 3. The connector structure in the invented link is a combination of a cylinder and a partial cone, which realizes the coupling of the photoconductive switch and the radio frequency connector and the impedance matching of the subsequent measurement circuit.

[0053] 4. The coaxial structure of the invented link can improve the power capacity of the overall input electrical pulse of the link.

[0054] 5. The invented link structure is compact, the influence of stray capacitance and stray inductance on the circuit is reduced, and the expansion of the coaxial link transmission signal frequency band is achieved.

[0055] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A photoconductive switch link assembly for realizing output microwave frequency band extension, characterized in that: The optical switch link assembly comprises an optical switch, a high voltage conductor, a connector, a ground conductor, a capacitor and a radio frequency connector, wherein the optical switch, the high voltage conductor, the connector, the ground conductor, the capacitor and the radio frequency connector are coaxially connected; The high-voltage conductor, the grounding conductor, the capacitor and the radio frequency connector are stacked, the capacitor is located between the high-voltage conductor and the grounding conductor, and the grounding conductor is located between the capacitor and the radio frequency connector; A receiving space is provided inside the capacitor, and the photoconductive switch is received in the receiving space; The input end of the photoconductive switch is connected to the high voltage conductor, the output end of the photoconductive switch is connected to the connector, and is connected to the radio frequency connector through the connector; A receiving cavity is provided on a side of the grounding conductor facing the capacitor, and the connecting body is located in the receiving cavity.

2. The optical switch link assembly according to claim 1, characterized in that: The input end and the output end are located on opposite sides of the photoconductive switch.

3. The optical switch link assembly according to claim 1, characterized in that: The high-voltage conductor is provided with a central through hole, and the input end of the photoconductive switch extends out through the central through hole and is fixedly connected to the high-voltage conductor via a fastener.

4. The optical switch link assembly according to claim 1, characterized in that: The connector includes an input portion and an output portion, wherein the input portion and the output portion are stacked; The input part is connected to the output end of the photoconductive switch, and the output part is connected to the radio frequency connector.

5. The optical switch link assembly according to claim 4, characterized in that: The input part is cylindrical, the output part is a part of a cone, and the radius of the end of the output part connected to the input part is greater than the radius of the end of the output part away from the input part.

6. The optical switch link assembly according to claim 4, characterized in that: The input portion is located in the receiving space.

7. The optical switch link assembly according to claim 1, characterized in that: A through hole is provided at the bottom of the receiving cavity, and the connecting end of the radio frequency connector is connected to the connecting body through the through hole.

8. The optical switch link assembly according to claim 1, characterized in that: The capacitor is a ring capacitor.

9. The optical switch link assembly according to claim 1, characterized in that: The capacitor includes a plurality of sub-capacitors, and the plurality of sub-capacitors form a ring shape with a receiving space in the middle.

10. The optical switch link assembly according to claim 9, characterized in that: The centers of the sub-capacitors are located on the same circle.

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