Low-loss high-reliability terahertz energy transmission window

Abstract

The invention provides a low-loss high-reliability terahertz energy transmission window. The energy transmission window comprises two window frames with waveguide cavities and a window sheet fixed between the two window frames, the window frame comprises a sealing structure for sealing the window sheet; the sealing structure comprises at least two annular sealing pieces and a plurality of connecting pieces, the annular sealing pieces abut against the end face of the window piece in the axial direction of the window frame, the annular sealing pieces and the window piece are coaxially arranged, and the connecting pieces abut against the end face of the window piece in the axial direction of the window frame. Each connecting piece is arranged between every two adjacent annular sealing pieces, and the connecting pieces are connected with the two annular sealing pieces; the connecting pieces between every two adjacent annular sealing pieces are arranged at intervals. The energy transmission window has the characteristics of small transmission loss and high structural reliability, so that the output power level and the engineering practical level of the terahertz traveling wave tube are effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of microwave vacuum electronics technology, and more specifically to a low-loss and high-reliability terahertz energy transmission window. Background Art

[0002] A traveling wave tube (TWT) is a vacuum electronic device capable of generating or amplifying microwave signals, and holds broad development prospects in fields such as communications, electronic countermeasures, and radar systems. A TWT primarily consists of an electron gun, a slow-wave structure, a collector, an input / output system, and a magnetic focusing system. The energy transfer window is a key component of this system, maintaining the vacuum within the tube while enabling the input and output of electromagnetic signals. Currently, the most commonly used energy transfer window in terahertz TWTs is a diamond box-type energy transfer window.

[0003] Figure 1 This is a conventional diamond box-type energy transmission window structure. The internal structure includes a straight waveguide, a circular waveguide, and a diamond window plate, forming a path for electromagnetic wave transmission. The external structure includes an upper window frame and a lower window frame. The upper window frame includes a connecting flange area for connecting to the test system, and the lower window frame includes a connecting plate area for welding to the tube body. The window frame material of conventional diamond box-type energy transmission windows is usually made of iron-nickel-cobalt magnetic sealing alloy (Kovar alloy). There are two main reasons for this. First, among the metal materials commonly used in vacuum devices, Kovar alloy has a thermal expansion coefficient closest to that of diamond material. During high-temperature welding, the sealing stress between the two is low, which easily meets the airtightness requirements of the energy transmission window. Second, the energy transmission window components need to be repeatedly connected to the test system through the connecting flange area and welded to the tube body through the connecting plate area. Kovar alloy has high strength and is not easily deformed during repeated connection with the test system. In addition, Kovar alloy is one of the tube shell materials, and the same material is conducive to argon arc welding.

[0004] However, this energy transmission window has two prominent problems: First, the transmission loss of the Kovar alloy material is high. As the device operating frequency increases to the terahertz band, the inherent loss of the window frame metal material has a more significant impact on the overall energy transmission system. Second, the terahertz waveguide and window are only millimeter-sized, and the sealing area is structurally weak and lacks effective support. In vehicle-mounted, airborne, and satellite-mounted environments, it is extremely prone to deformation and mechanical failure due to high vibration and impact loads, thus limiting the engineering level of terahertz traveling wave tubes. Summary of the Invention

[0005] In response to the above problems, the present invention provides a low-loss and high-reliability terahertz energy transmission window that has the characteristics of low transmission loss and high structural reliability, thereby effectively improving the output power level and engineering practicality of the terahertz traveling wave tube.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a low-loss and high-reliability terahertz energy transmission window, comprising:

[0008] Two window frames with waveguide cavities and a window sheet fixed between the two window frames;

[0009] The window frame includes a sealing structure for encapsulating the window sheet;

[0010] The sealing structure includes at least two annular sealing members abutting against the end surface of the window piece along the axial direction of the window frame, the annular sealing members are coaxially arranged with the window piece, and a plurality of connecting members abutting against the end surface of the window piece along the axial direction of the window frame;

[0011] The connecting piece is arranged between two adjacent annular sealing pieces and is connected to both annular sealing pieces; the connecting piece between two adjacent annular sealing pieces is arranged at intervals.

[0012] A preferred solution is that a spacing space is formed between two adjacent annular sealing members, and the connecting members are evenly arranged in the spacing space along the circumference of the annular sealing members.

[0013] A preferred solution is that the number of the annular sealing members is at least three; different spaces have the same number of connecting members, and the positions of the connecting members in adjacent spaces are non-corresponding.

[0014] A preferred solution is that the ring widths of adjacent annular sealing members are equal, and the spacing distances between adjacent annular sealing members are equal; the ring width of the annular sealing member is L1, and L1 ≥ 0.1 mm.

[0015] A preferred solution is that the number of connecting pieces between two adjacent annular sealing pieces is at least three, and the width of the connecting piece is M, 0.2 mm ≤ M ≤ 0.6 mm.

[0016] A preferred solution is that the waveguide cavity includes a connected straight waveguide cavity and a circular waveguide cavity, the cavity height of the circular waveguide cavity is H1, the annular sealing member and the connecting member have the same height, the height of the annular sealing member is H2, H1>H2 and 0.1mm≤H2≤0.3mm.

[0017] The preferred embodiment is that the energy transmission window includes an upper window frame, a lower window frame fixed to the upper window frame, a connecting flange fixed to both the upper window frame and the lower window frame, and a connecting piece fixed to the lower window frame; the window piece 3 is fixed between the upper window frame and the lower window frame;

[0018] The upper window frame and the lower window frame are both made of oxygen-free copper, the window piece is made of diamond, and the connecting flange is made of Kovar alloy.

[0019] A preferred solution is that the inner diameter of the connecting flange is D3, the maximum outer diameter of the lower window frame is D4; 1mm≤D4-D3≤3mm.

[0020] A preferred solution is that the diameter of the window piece is D2, the inner diameter of the connecting piece is D5; D2≤D5≤D4-1mm.

[0021] A preferred solution is that the height of the sealing surface between the lower window frame and the connecting flange is H3, and the height of the connecting flange is H4; 0.3≤H3:H4≤0.6.

[0022] The beneficial effects of the present invention are:

[0023] By providing a sealing structure on the sealing surface between the window frame and the window sheet, the present invention can evenly discretize the sealing surface in the circumferential and radial directions, increase the local deformation freedom, change the stress transmission path, and redistribute the stress within the sealing structure to avoid stress concentration. At the same time, the sealing structure can independently deform to release thermal stress, thereby significantly reducing the overall sealing stress and improving the sealing reliability of the energy transmission window. The original terahertz energy transmission window has a large transmission loss. The present invention uses oxygen-free copper instead of Kovar alloy as the window frame material to significantly reduce the transmission loss of the terahertz energy transmission window. At the same time, the sealing structure is used to significantly reduce the sealing stress and ensure the seal is airtight. Taking the G band as an example, the energy transmission window of the present invention can achieve a transmission loss reduction from 1.3dB to 0.5dB, a reduction of 61%, which can significantly improve the output power level of the terahertz traveling wave tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0025] Figure 1 This is a schematic diagram of the structure of a conventional diamond box-type energy transmission window.

[0026] Figure 2 It is a schematic structural diagram of the energy transmission window of the present invention.

[0027] Figure 3 It is a structural schematic diagram of an upper window frame of the present invention.

[0028] Figure 4 It is a bottom view of an upper window frame of the present invention.

[0029] Figure 5 It is a structural schematic diagram of the lower window frame of the present invention.

[0030] Figure 6 This is a schematic diagram of the thermal stress simulation results of a conventional diamond box-type energy transmission window.

[0031] Figure 7 It is a schematic diagram of the thermal stress simulation results of the energy transmission window of the present invention.

[0032] Figure 8 It is a comparison chart of the measured transmission loss results of the conventional diamond box type energy transmission window and the energy transmission window of the present invention.

[0033] Figure 9 This is the test result diagram of the first 6 natural vibration frequencies of a conventional diamond box-type energy transmission window.

[0034] Figure 10 This is a test result diagram of the first 6 natural vibration frequencies of the energy transmission window structure of the present invention.

[0035] Figure numerals: 1, upper window frame, 2, lower window frame, 3, window piece, 4, connecting flange, 5, connecting piece, 11, boss, 12, groove, 13, sealing structure, 14, step, 15, first assembly groove, 16, second assembly groove, 131, sealing part, 132, annular groove, 133, connecting part, 111, circular waveguide cavity, 112, straight waveguide cavity. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0037] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0038] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0039] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0040] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0041] Taking the G band as an example, the transmission loss in a straight waveguide structure made of oxygen-free copper is 13.5dB / m, while that made of Kovar alloy can reach 100dB / m. Furthermore, the metal loss accounts for as much as 98% of the transmission loss in the terahertz energy transmission window. This directly increases the transmission loss of the terahertz traveling wave tube input / output system, severely limiting the output power level of the terahertz traveling wave tube. Furthermore, the terahertz waveguide and window are only millimeter-sized, and the sealing area is structurally weak and lacks effective support. Under high vibration and shock loads in vehicle-mounted, airborne, and satellite-mounted environments, deformation and mechanical failure are highly likely, thus limiting the engineering level of the terahertz traveling wave tube. To reduce the loss, the upper and lower window frames were first changed from Kovar alloy to oxygen-free copper, significantly reducing the transmission loss of the metal portion. However, the thermal expansion coefficient ratio of oxygen-free copper to diamond is as high as 7:1, far higher than the 3:1 ratio of Kovar alloy to diamond. If an oxygen-free copper window frame is used in a conventional diamond energy window structure, the thermal stress of the oxygen-free copper window frame during sealing will increase significantly, which can easily lead to seal failure. Therefore, it is necessary to design a new terahertz energy window structure that balances low loss and high reliability.

[0042] In order to solve the problems existing in the prior art, the present invention provides a low-loss and high-reliability terahertz energy transmission window. Figures 1 to 10 As shown, specifically, the low-loss and high-reliability terahertz energy transmission window includes: two window frames with waveguide cavities and a window piece 3 fixed between the two window frames; the window frame includes a sealing structure 13 for encapsulating the window piece 3; the sealing structure 13 includes at least two annular sealing members 131 axially abutting against the end face of the window piece 3 along the window frame, and the annular sealing members 131 are all coaxially arranged with the window piece 3, and a plurality of connecting members 133 axially abutting against the end face of the window piece 3 along the window frame; the connecting member 133 is arranged between two adjacent annular sealing members 131 and the connecting member 133 is connected to both annular sealing members 131; the connecting members 133 between two adjacent annular sealing members 131 are arranged at intervals. This energy transmission window takes into account the characteristics of low transmission loss and high structural reliability, thereby improving the output power level and engineering practicality of the terahertz traveling wave tube. The present invention forms a sealing structure similar to a mesh structure through the cooperation of annular sealing members and connecting members. The present invention utilizes a mesh-like sealing structure at the interface between the window frame and the window slat, discretizing the sealing surface in both the circumferential and radial directions. This increases the degree of freedom for local deformation of the sealing surface and significantly reduces the sealing stress at the junction between the window slat and the window frame. It should be understood that the sealing surface refers to the plane where the end faces of the window frame and window slat meet. The present invention utilizes a sealing structure that transforms this plane into a mesh-like surface, allowing the sealing surface to maintain discretization and the ability to locally deform while ensuring a seal with the window slat.

[0043] Further regarding the sealing structure 13, adjacent annular sealing members 131 are coaxially arranged, and a spacing space 132 is formed between two adjacent annular sealing members 131. The connecting members 133 are evenly arranged in the spacing space 132 along the circumference of the annular sealing members 131. The spacing space 132 is equivalent to a ring groove located between two adjacent annular sealing members 131 formed by the inward depression of part of the surface of the complete sealing surface. The connecting member 133 divides the spacing space 132 into a number of mutually isolated arc grooves. The connecting member 133 is connected to the sealing member 131 to form a mesh structure surrounding the outside of the circular waveguide cavity 111. By designing a mesh structure on the sealing surface between the window frame and the window plate 3, the sealing surface is discretized in both the circumferential direction and the radial direction, increasing the degree of freedom of local deformation of the sealing surface, thereby significantly reducing the sealing stress at the sealing point between the window plate and the window frame.

[0044] There are at least three annular sealing members 131, with the same number of connectors 133 within different compartments 132. The connectors 133 within adjacent compartments 132 are arranged in non-corresponding positions. By staggering the connectors 133 within each annular groove, the discrete sealing surface is maximized in the radial direction and the structural reinforcement effect is enhanced, avoiding the situation where the discrete sealing surface and the structural reinforcement effect are reduced when the connector strips in two adjacent annular grooves are positioned in the same position.

[0045] In one specific embodiment, adjacent annular sealing elements 131 have equal widths and are spaced evenly apart. The width of the annular sealing elements 131 is L1, where L1 ≥ 0.1 mm. Within this range, the sealing surface exhibits sufficient discretization in the circumferential direction, and the sealing elements have sufficient width, effectively reducing sealing stress while ensuring airtightness through the use of multiple sealing elements.

[0046] Furthermore, the waveguide cavity includes a straight waveguide cavity 112 and a circular waveguide cavity 111 that are connected. The diameter of the circular waveguide cavity 111 is D1, the diameter of the window 3 is D2, (D2-D1) / 2 is the ring width of the sealing surface area, and N1 annular sealing members 131 are evenly distributed within this ring width, where N1≥2. The width of the annular sealing member 131 is L1, and the width of the annular groove is L2, where L2=((D2-D1) / 2-N1×L1) / (N1-1). When N1<2, the discreteness of the sealing surface is insufficient, and the sealing stress cannot be effectively reduced. When the N1 value is too large, resulting in L1<0.1mm, the width of the annular sealing member 131 is too narrow, and it is easy for tiny flaws on the surface of the part to form a passage, resulting in poor airtightness.

[0047] In a specific embodiment, the number N2 of connectors 133 in an annular groove is at least three, that is, N2 is greater than or equal to 3. The width of the connector 133 is M, 0.2mm≤M≤0.6mm. Within the above range, the connector 133 can form a sufficiently effective structural reinforcement for the radially discrete annular sealing member 131 while achieving circumferential discreteness of the sealing surface, effectively reducing the sealing stress while improving the strength of the structure. When N2<3 or M<0.2mm, the structural reinforcement of the radially discrete sealing member is insufficient, and large deformation is likely to occur during the processing and sealing process. When M>0.6mm, the degree of discreteness of the sealing surface is insufficient, and the sealing stress cannot be effectively reduced.

[0048] In a specific embodiment, the cavity height of the circular waveguide cavity 111 is H1, the annular sealing member 131 and the connecting member 133 have the same height, and the height of the annular sealing member 131 is H2. H1>H2 and 0.1mm≤H2≤0.3mm. Within the above range, the structural strength of the sealing surface area and the need for local free deformation can be taken into account. When H2<0.1mm, the height is too small, the local deformation capacity of the sealing surface is limited, and the sealing stress cannot be effectively released; when H2>0.3mm, the height is too large, resulting in insufficient strength in the sealing area.

[0049] In a specific embodiment, the energy transmission window includes an upper window frame 1, a lower window frame 2 fixed to the upper window frame 1, a connection flange 4 fixed to both the upper window frame 1 and the lower window frame 2, and a connection piece 5 fixed to the lower window frame 2; a window pane 3 is fixed between the upper window frame 1 and the lower window frame 2. The connection flange 4 is assembled on a first assembly groove 15 on the lower window frame 2, and the connection piece 5 is assembled on a second assembly groove 16 on the lower window frame 2. The materials of the upper window frame 1 and the lower window frame 2 are both oxygen-free copper, the material of the window pane 3 is diamond, and the material of the connection flange 4 is kovar alloy. A boss 11 is formed on the upper window frame 1, and a groove 12 for assembling with the boss 11 is formed on the lower window frame 2. Sealing structures 13 are formed on both the boss 11 and the groove 12, and the two sealing structures 13 are symmetrically arranged on both sides of the window pane 3 along the axial direction of the energy transmission window. The diameter of the window pane is D2, the inner diameter of the connection flange is D3, the maximum outer diameter of the lower window frame is D4, the inner diameter of the connection piece is D5, the height of the sealing surface between the lower window frame and the connection flange is H3, and the height of the connection flange is H4; 1mm ≤ D4 - D3 ≤ 3mm; D2 ≤ D5 ≤ D4 - 1mm; 0.3 ≤ H3:H4 ≤ 0.6. More specifically, for the design aiming at improving reliability, the upper window frame 1 and the connection flange 4, as well as the lower window frame 2 and the connection piece 5, are designed as split structures. The upper and lower window frames are made of oxygen-free copper material, and the connection flange 4 and the connection piece 5 are made of kovar alloy material. On the one hand, taking advantage of the high strength of kovar alloy and the same material as the tube shell, the reliability of the repeated connection between the connection flange 4 and the signal input / output system, and the reliability of the welding between the connection piece 5 and the tube shell are ensured. On the other hand, the connection flange 4 is used as a reinforcement support and brazed to the upper and lower window frames at the same time, providing effective protection and support for the structure of the sealing area and enhancing the overall structural stiffness of the energy transmission window. D3 is the inner diameter of the connection flange, D4 is the maximum outer diameter of the lower window frame, D5 is the inner diameter of the connection piece, H3 is the height of the sealing surface between the lower window frame and the connection flange, and H4 is the height of the connection flange. Among them, 1mm ≤ D4 - D3 ≤ 3mm. Within this range, the top surface ring width of the step 14 of the lower window frame 2 surrounding the groove 12 is moderate, which can provide limit and structural support for the connection flange 4 in the horizontal direction. When D4 - D3 < 1mm, the top surface ring width of the step 14 of the lower window frame is too narrow to effectively support the connection flange, affecting the horizontal direction fitting accuracy and the structural strength after brazing. When D4 - D3 > 3mm, the distance between the maximum outer diameter of the lower window frame and the connection flange is too close, which is likely to affect the operation of the connection screw. D2 ≤ D5 ≤ D4 - 1mm. Within this range, the fitting surface dimensions of the lower window frame 2 and the connection piece 5 are moderate, which can take into account both the fitting accuracy and the structural strength after brazing. When D5 < D2, the brazing surface of the lower window frame and the connection piece is too close to the straight waveguide, and the solder is likely to flow into the straight waveguide, affecting the transmission loss. When D5 > D4 - 1mm, the brazing surface of the lower window frame and the connection piece is too narrow, affecting the structural strength after welding.0.3≤H3:H4≤0.6. Within this range, the oxygen-free copper-diamond sealing surface is located in the middle area of ​​the connecting flange 4. The connecting flange 4 can form an effective reinforcement support for the overall structure. If it is outside this range, the mating surface height of the connecting flange and the upper window frame or the lower window frame is not high enough, which affects the reinforcement support effect. The sealing area of ​​the original energy transmission window structure is weak. The present invention uses the connecting flange structure as a reinforcement structure between the upper and lower window frames to provide effective protection and support for the sealing area. The modal analysis results show that the first-order natural frequency of the energy transmission window component is increased from 4689.5Hz to 13541Hz, an increase of about 190%, which can greatly improve the structural stiffness of the terahertz traveling wave tube energy transmission system and better meet the use environments such as vehicle-mounted, airborne, and satellite-mounted. The sealing area of ​​the upper and lower window frames of the present invention is enclosed inside the connecting flange, and the overall size of the energy transmission window in the height direction can be shortened by more than 30%, further reducing the transmission loss and facilitating the miniaturization design of the terahertz traveling wave tube.

[0050] Specifically, taking the G-band energy transmission window as an example, D1 = 1.8mm, D2 = 3.5mm, H1 = 0.3mm, D3 = 7mm, H4 = 3mm, N1 = 4, L1 = 0.1mm, L2 = 0.15mm, N2 = 4, M = 0.2mm, H2 = 0.2mm, D4-D3 = 2mm, i.e. D4 = 9mm, D5 = D4-3mm = 6mm, H3:H4 = 0.5, i.e. H3 = 1.5mm. Ansys simulation is performed on the sealing thermal stress of the energy transmission window using oxygen-free copper window frame and diamond window. Figure 6 The thermal stress simulation results of the energy transmission window with conventional structure are shown. The maximum principal stress on the window surface is 451.9MPa. Figure 7 The thermal stress simulation results of the energy transmission window of the present invention show that the maximum thermal stress of the seal is reduced to 51.2MPa after the structure of the present invention is adopted, which is lower than the tensile strength of the sealing surface of 116MPa, indicating that the structure of the present invention can achieve the airtightness of the oxygen-free copper-diamond energy transmission window. Accordingly, the oxygen-free copper window frame, Kovar alloy connecting flange and connecting piece were processed using this set of dimensional parameters, assembled with the diamond window piece and sealed. After the sample was sealed, it was tested for airtightness using a nitrogen chamber leak detector, and the helium leak rate was ≤1×10 -11 Pa·m 3 / s, meeting the airtightness requirements. Figure 8 The measured transmission loss results for conventional Kovar alloy-diamond energy transmission windows and the oxygen-free copper-diamond energy transmission window of the present invention show that the average measured transmission loss of the energy transmission window of the present invention is 0.5dB, which is about 61% lower than the average transmission loss of 1.3dB for conventional Kovar alloy-diamond energy transmission windows. Figure 9 These are the first six natural vibration frequencies of the oxygen-free copper-diamond energy transmission window under conventional structure. Figure 10These are the first six natural vibration frequencies of the oxygen-free copper-diamond energy transmission window of the present invention. The results show that after adopting the structure of the present invention, the first-order natural frequency of the energy transmission window is greatly increased from 4689.5 Hz to 13541 Hz, an increase of about 190%, which can greatly improve the structural stiffness of the terahertz traveling wave tube energy transmission system.

[0051] The present invention also provides a traveling wave tube, which includes: a high-frequency system having an electromagnetic wave input structure and an electromagnetic wave output structure; an electron gun located at one end of the high-frequency system; and a collecting electrode located at an end of the high-frequency system away from the electron gun; at least one of the electromagnetic wave input structure and the electromagnetic wave output structure includes the energy transmission window as described above.

[0052] In summary, the present invention, by providing a sealing structure on the sealing surface between the window frame and the window sheet, can uniformly discretize the sealing surface in the circumferential and radial directions, increase the local deformation freedom, change the stress transmission path, and redistribute the stress within the sealing structure to avoid stress concentration. At the same time, the thermal stress can be released by the independent deformation of the sealing structure, thereby significantly reducing the overall sealing stress and improving the sealing reliability of the energy transmission window. The original terahertz energy transmission window has a large transmission loss. The present invention uses oxygen-free copper instead of Kovar alloy as the window frame material to significantly reduce the transmission loss of the terahertz energy transmission window. At the same time, the sealing structure is used to significantly reduce the sealing stress and ensure the airtightness of the seal. Taking the G band as an example, the energy transmission window of the present invention can achieve a transmission loss reduction from 1.3dB to 0.5dB, a reduction of 61%, which can significantly improve the output power level of the terahertz traveling wave tube.

[0053] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A low-loss and high-reliability terahertz energy transmission window, characterized in that: include: Two window frames with waveguide cavities and a window sheet fixed between the two window frames; The window frame includes a sealing structure for encapsulating the window sheet; The sealing structure includes at least two annular sealing members abutting against the end surface of the window piece along the axial direction of the window frame, the annular sealing members are coaxially arranged with the window piece, and a plurality of connecting members abutting against the end surface of the window piece along the axial direction of the window frame; The connecting piece is arranged between two adjacent annular sealing pieces and is connected to both annular sealing pieces; the connecting piece between two adjacent annular sealing pieces is arranged at intervals.

2. The low-loss and high-reliability terahertz energy transmission window according to claim 1, characterized in that: A spacing space is formed between two adjacent annular sealing members, and the connecting members are evenly arranged in the spacing space along the circumference of the annular sealing members.

3. The low-loss and high-reliability terahertz energy transmission window according to claim 2, characterized in that: The number of the annular sealing members is at least three; different spaces have the same number of connecting members, and the positions of the connecting members in adjacent spaces are non-corresponding.

4. The low-loss and high-reliability terahertz energy transmission window according to claim 3, characterized in that: The ring widths of adjacent annular sealing members are equal, and the spacing distances between adjacent annular sealing members are equal; the ring width of the annular sealing member is L1, and L1 is ≥ 0.1 mm.

5. The low-loss and high-reliability terahertz energy transmission window according to claim 1, characterized in that: The number of connecting pieces between two adjacent annular sealing pieces is at least three, and the width of the connecting piece is M, 0.2 mm ≤ M ≤ 0.6 mm.

6. The low-loss and high-reliability terahertz energy transmission window according to claim 1, characterized in that: The waveguide cavity includes a straight waveguide cavity and a circular waveguide cavity that are connected. The cavity height of the circular waveguide cavity is H1. The annular sealing member and the connecting member have the same height. The height of the annular sealing member is H2, H1>H2 and 0.1mm≤H2≤0.3mm.

7. The low-loss and high-reliability terahertz energy transmission window according to claim 1, characterized in that: The energy transmission window includes an upper window frame, a lower window frame fixed to the upper window frame, a connecting flange fixed to both the upper window frame and the lower window frame, and a connecting piece fixed to the lower window frame; the window piece is fixed between the upper window frame and the lower window frame; The upper window frame and the lower window frame are both made of oxygen-free copper, the window piece is made of diamond, and the connecting flange is made of Kovar alloy.

8. The low-loss and high-reliability terahertz energy transmission window according to claim 7, characterized in that: The inner diameter of the connecting flange is D3, and the maximum outer diameter of the lower window frame is D4; 1mm≤D4-D3≤3mm.

9. The low-loss and high-reliability terahertz energy transmission window according to claim 8, characterized in that: The diameter of the window piece is D2, and the inner diameter of the connecting piece is D5; D2≤D5≤D4-1mm.

10. The low-loss and high-reliability terahertz energy transmission window according to claim 7, characterized in that: The sealing surface height between the lower window frame and the connecting flange is H3, and the connecting flange height is H4; 0.3≤H3:H4≤0.6.

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