CN106785245B - Low-loss high-vacuum sealing heat-insulation transmission window for millimeter wave frequency band - Google Patents
Low-loss high-vacuum sealing heat-insulation transmission window for millimeter wave frequency band Download PDFInfo
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- CN106785245B CN106785245B CN201611103385.XA CN201611103385A CN106785245B CN 106785245 B CN106785245 B CN 106785245B CN 201611103385 A CN201611103385 A CN 201611103385A CN 106785245 B CN106785245 B CN 106785245B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/08—Dielectric windows
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
- H01Q19/10—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces
- H01Q19/18—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces having two or more spaced reflecting surfaces
- H01Q19/19—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces having two or more spaced reflecting surfaces comprising one main concave reflecting surface associated with an auxiliary reflecting surface
Abstract
The invention relates to a low-loss high-vacuum sealed heat-insulation transmission window for a millimeter wave frequency band, which comprises a multilayer dielectric window, and a sealed upper flange and a sealed lower flange which are respectively arranged at the upper side and the lower side of the edge of the multilayer dielectric window; the multilayer dielectric window comprises a first four-fluorine layer, a quartz layer, a second four-fluorine layer and a heat insulation layer which are sequentially arranged from outside to inside. The invention not only can effectively reduce the transmission reflection loss of electromagnetic wave signals, improve the problem that a large number of interference bands exist in the existing window, but also can greatly improve the vacuum sealing performance, solve the problem that the use of the sealed wave-transmitting window of the traditional low-temperature receiver/superconducting receiver is limited, has good heat insulation effect and effectively reduces heat radiation.
Description
Technical Field
The invention relates to the technical field of microwave signal transmission window components, in particular to a low-loss high-vacuum sealing heat-insulation transmission window for a millimeter wave frequency band.
Background
The sealed window is mainly used for transmitting light and microwave signals and has vacuum sealing capability. At present, the sealing window technology is mainly used in infrared detectors, low-temperature receivers and superconducting receivers.
In infrared applications, the sealed window is mainly made of sapphire materials, and the sealed window is required to have good light transmittance and maintain good vacuum degree, but the sealed window has a large dielectric constant and is generally not suitable for transmission of microwave signals.
For microwave transmission windows for cryogenic receivers/superconducting receivers, three common materials for constructing wave-transparent windows are rigid foam plates, polyimide films and polytetrafluoroethylene plates: the rigid foam board has the minimum loss, the dielectric constant is close to air, the optimization of signal transmission characteristics can be realized, but the sealing requirement of a window cannot be realized, and the rigid foam board is usually matched with a polyimide film for use; the polyimide film has a large dielectric constant, is not favorable for signal transmission, and generally faces the problem of deterioration of return loss of the antenna (particularly in a millimeter wave frequency band); the polytetrafluoroethylene plate has good heat insulation effect and low loss, but has a larger dielectric constant than rigid foam, and the problem of deterioration of return loss of the antenna also exists. Moreover, the vacuum sealing performance of the sealed transmission window made of the tetrafluoro and polyimide films is poor, and the good vacuum degree cannot be kept for a long time (the vacuum leakage rate is generally 5.01 х 10)-9Pa m3S; after standing for 24h, the vacuum degree deterioration was 1.01 х 102Pa or so); the window made of the polytetrafluoroethylene and the polyeneimine film is easy to deform and influence the use performance after being used for a long time under negative pressure. Meanwhile, the transmission window in the above technology is mostly a planar structure, and has certain limitation to the transmission application of microwave signals: the microwave signal transmission window is generally matched with an antenna, a feed source and a receiver for use, the feed source is used for receiving signals of the antenna, the feed source is usually arranged inside the receiver (inside a sealed transmission window and a Dewar), other metal objects are not allowed to exist between the end face of the feed source and the reflecting surface of the antenna in the feed-forward type antenna (if the metal objects exist, the performance of the antenna is affected), and the transmission window adopting a planar structure cannot meet the system requirement necessarily.
Disclosure of Invention
The invention aims to provide a low-loss high-vacuum sealed heat-insulation transmission window for a millimeter wave frequency band, which can effectively reduce the transmission and reflection loss of electromagnetic wave signals, improve the problem that a large number of interference bands exist in the existing window, greatly improve the vacuum sealing performance, solve the problem that the use of the traditional low-temperature receiver/superconducting receiver sealed wave-transparent window is limited, has a good heat-insulation effect and effectively reduces heat radiation.
In order to achieve the purpose, the invention adopts the following technical scheme:
a low-loss high-vacuum sealed heat-insulation transmission window for a millimeter wave frequency band comprises a multilayer dielectric window, and a sealed upper flange and a sealed lower flange which are respectively arranged on the upper side and the lower side of the multilayer dielectric window. The multilayer dielectric window comprises a first four-fluorine layer, a quartz layer, a second four-fluorine layer and a heat insulation layer which are sequentially arranged from outside to inside.
Furthermore, the first teflon layer and the second teflon layer are made of polytetrafluoroethylene elastic plate materials.
Furthermore, the first teflon layer and the second teflon layer are respectively bonded on the outer side and the inner side of the quartz layer by adopting low-loss optical epoxy glue, and no gap is left between the layers by heating, pressurizing and curing.
Further, the quartz layer is made of high-purity fused quartz material.
Further, the quartz layer comprises a cover shell and a crimping edge arranged along the periphery of the lower end of the cover shell; and the upper side and the lower side of the crimping edge are respectively provided with a metal sealing ring. The structure of the quartz layer is a bell jar type, and the first teflon layer and the second teflon layer are respectively bonded on the outer wall and the inner wall of the quartz layer. The heat insulating layer is adhered to the inner wall of the second PTFE layer. The structure of the whole multi-layer dielectric window is also bell-shaped. The upper sealing flange and the lower sealing flange are respectively arranged at the upper side and the lower side of the crimping edge.
Furthermore, the heat insulation layer is made of polystyrene foam.
Furthermore, a plurality of through holes are formed in the heat insulation layer.
Furthermore, the sealing upper flange and the sealing lower flange are made of kovar alloy 4J 29.
Furthermore, stress grooves are formed in the upper sealing flange and the lower sealing flange, the stress grooves are circular, and the distance between the outer diameter of each stress groove and the outer edge of each sealing flange is kept between 2mm and 5 mm.
Furthermore, the upper sealing flange and the lower sealing flange are fixedly installed on the crimping edge and the metal sealing rings on the upper side and the lower side of the crimping edge in a screw fastening mode, and sealing is achieved.
According to the technical scheme, the multi-layer dielectric window is formed by adopting the multi-layer dielectric material, so that the transmission and reflection loss of electromagnetic wave signals is reduced, particularly in a millimeter wave frequency band, the return loss is below-20 dB, and the transmission loss is better than 0.05 dB. The matching of different dielectric constants of the multiple layers of media in the multi-layer dielectric window improves the problem that a large number of interference bands (broadband reception and interference signals can enter) exist in the existing window, and the filtering effect is improved (more than 20 dB). The polystyrene material adopted by the heat insulation layer also has the heat insulation effect, and the heat radiation is reduced. Meanwhile, the vacuum sealing performance of the low-temperature/superconducting receiver can be greatly improved, so that the vacuum leakage rate reaches 5.01 х 10-11Pa m3The ratio of the water to the water is less than s. The structure of the bell jar adopted by the invention can also meet the use requirements of most systems and solve the problem of limited use. In the low-loss high-vacuum-sealing heat-insulation transmission window for the millimeter wave frequency band, electromagnetic wave signals enter the inside of the receiver through the multi-layer dielectric window made of the multi-layer dielectric material, so that the low-loss high-vacuum-sealing performance of the receiver is ensured, out-of-band interference signals can be filtered, and the heat insulation layer can effectively reduce heat radiation; the bell-jar structure can be applied to a feed-forward antenna system, so that no metal shielding on a feed source surface is ensured, the application occasion of a receiver is effectively expanded, and the problem of limited use is solved. The invention has the characteristics of small signal transmission loss, long static vacuum maintaining time, high reliability and the like.
Drawings
FIG. 1 is a schematic cross-sectional view of the present invention;
FIG. 2 is a schematic diagram of the structure of a multi-layer dielectric window of the present invention;
FIG. 3 is a schematic view of the structure of the heat insulating layer according to the present invention;
FIG. 4 is a schematic view of the vacuum sealing mode of the present invention;
fig. 5 is a schematic diagram of an exemplary application of the present invention.
Wherein:
1. the antenna comprises a multi-layer dielectric window, 2, a sealing upper flange, 3, a sealing lower flange, 4, a first teflon layer, 5, a quartz layer, 6, a heat insulation layer, 7, a through hole, 8, a metal sealing ring, 9, a crimping edge, 10, an antenna secondary reflection surface, 11, an antenna main reflection surface, 12, a Dewar, 13, a receiving front end component, 14, a refrigerator, 15, a feed source, 16, a feed surface, 17, a second teflon layer, 18 and a stress groove.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
fig. 1 is a schematic structural diagram of a low-loss high-vacuum sealed heat-insulating transmission window for a millimeter wave frequency band, where the transmission window includes a multi-layer dielectric window 1, a sealed upper flange 2, and a sealed lower flange 3. The sealing flange is usually used in cooperation with a metal sealing ring and is fastened in a compression joint mode to achieve the metal air sealing effect. The invention is used as a signal input port of a low-temperature receiver and a superconducting receiver, and plays roles of wave transmission and vacuum sealing. The invention is used for solving the problems of large return loss (especially in millimeter wave band), easy introduction of interference signals, poor vacuum tightness and limited use caused by a window structure of the existing low-temperature/superconducting receiver sealed wave-transmitting window.
As shown in fig. 2, the multi-layered dielectric window has 4 layers in total, and includes a first teflon layer 4, a quartz layer 5, a second teflon layer 17, and a thermal insulation layer 6 from the outside to the inside. The first teflon layer and the second teflon layer are made of polytetrafluoroethylene elastic plates (soft tetrafluoro) which are soft, so that the first teflon layer and the second teflon layer can be attached to the quartz layer conveniently, and seamless bonding is achieved. The quartz layer is made of high-purity fused quartz material, and the structural appearance of the quartz layer is bell-jar type. The heat insulation layer is made of polystyrene foam. The first tetrafluoro layer is connected to the outer side wall of the quartz layer by heating, pressurizing, curing and pressing by using low-loss epoxy optical cement as an adhesive. The second tetrafluoro layer is connected to the inner side wall of the quartz layer by heating, pressurizing, curing and pressing by adopting low-loss epoxy optical cement as an adhesive. And gaps are not formed among the quartz layer, the first teflon layer and the second teflon layer by heating, pressurizing, curing and pressure welding. The multi-layer dielectric window adopted by the invention is in a bell jar shape, and meanwhile, the metal sealing ring is made of soft metal material indium to realize the high vacuum sealing of the multi-layer dielectric window and the upper and lower sealing flanges, and then the upper and lower sealing flanges are welded on the Dewar to realize the integral high vacuum sealing. The invention adopts multilayer dielectric materials to manufacture the multilayer dielectric window, thereby reducing the transmission and reflection loss of electromagnetic wave signals; the multi-dielectric constant matching of the multi-layer dielectric window improves the problem that a large number of interference bands (broadband reception and interference signals can enter) exist in the existing window, and the filtering effect is improved; the heat insulation layer is made of the polystyrene material, has a heat insulation effect, and can reduce heat radiation.
As shown in fig. 3, the thermal insulation layer 6 is provided with a plurality of through holes 7, and the through holes are used for accelerating the release speed of residual gas between the thermal insulation layer and other layers.
As shown in fig. 4, the quartz layer 5 includes a mantle and a crimping rim 9 provided along the outer periphery of the lower end of the mantle. The crimping edge 9 is provided for vacuum sealing. The upper and lower surfaces of the crimping edge 9 are respectively provided with a metal sealing ring 8. And metal compression joint sealing is carried out on the quartz layer and the metal sealing ring in a mode of fastening the upper sealing flange and the lower sealing flange by screws. The metal sealing ring 8 is made of soft metal-indium. The upper sealing flange 2 and the lower sealing flange 3 are both made of a valve alloy 4J29 material, a stress groove 18 is formed in the upper sealing flange and the lower sealing flange, and the stress groove is used for releasing expansion stress caused by heating of the material in the welding process, reducing deformation and improving the welding vacuum sealing performance. The invention adopts the mode of combining the metal sealing ring made of soft metal indium and the sealing flange, can greatly improve the vacuum sealing performance and ensure that the vacuum leakage rate reaches 5.01 х 10-11Pa m3The ratio of the water to the water is less than s.
Fig. 5 is a schematic diagram of an exemplary application of the present invention, in which a low-loss high-vacuum-sealing heat-insulating transmission window for a millimeter wave frequency band is applied to a low-temperature receiver/superconducting receiver as a transmission window of a signal, and the application modes are as follows: the signal received by the antenna main reflecting surface 11 is fed back to the antenna auxiliary reflecting surface 10, the signal is transmitted to the feed source 15 through the multi-layer dielectric window 1 in the low-loss high-vacuum sealed heat insulation transmission window, and is filtered, amplified and output through the receiving front end component 13, wherein the refrigerator 14 provides a low-temperature environment required by work for the feed source and the receiving front end component, and the dewar 12 and the low-loss high-vacuum sealed heat insulation transmission window provide a high-vacuum sealed heat insulation environment for the feed source and the receiving front end component. Meanwhile, the feed source and the low-loss high-vacuum sealing heat insulation transmission window extend into the bottom of the main reflection surface 11 of the antenna, and the space above the feed surface 16 of the feed source does not allow other metal objects to exist, otherwise, the performance of the antenna is deteriorated.
In summary, the present invention adopts multiple layers of dielectric materials as the wave-transparent window, wherein the first teflon layer/the quartz layer/the second teflon layer has the function of sealing the wave-transparent transmission window with low loss, and also has the function of filtering; and the wave-transmitting window adopts polystyrene material as a heat insulation layer to carry out heat insulation shielding so as to reduce radiant heat. The invention realizes the high vacuum sealing of the multi-layer dielectric window and the upper and lower sealing flanges by adopting the metal sealing ring made of soft metal material indium. The invention adopts the multilayer dielectric window with the bell-type structure, can solve the problem that the wave-transparent window system of the low-temperature receiver is limited in use at the present stage, and expands the application range. In the application of a low-temperature/superconducting receiver system, the matching of the multi-layer dielectric material of the multi-layer dielectric window can effectively reduce the transmission and reflection loss of electromagnetic wave signals and the entrance of out-of-band interference signals, and has the characteristics of low insertion loss and good out-of-band filtering; meanwhile, the vacuum insulation device has the advantages of high vacuum degree, long static vacuum retention time, good heat insulation effect, high reliability and the like.
The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention without departing from the spirit of the present invention.
Claims (5)
1. The utility model provides a millimeter wave frequency channel is with high vacuum seal transmission window that insulates against heat of low-loss which characterized in that: the sealing device comprises a multi-layer dielectric window, and an upper sealing flange and a lower sealing flange which are respectively arranged on the upper side and the lower side of the multi-layer dielectric window; the multilayer dielectric window comprises a first teflon layer, a quartz layer, a second teflon layer and a heat insulation layer which are sequentially arranged from outside to inside;
the first teflon layer and the second teflon layer are made of polytetrafluoroethylene elastic plate materials;
the first teflon layer and the second teflon layer are respectively bonded on the outer side and the inner side of the quartz layer by adopting optical epoxy glue; the quartz layer comprises a housing and a crimping edge arranged along the periphery of the lower end of the housing; the upper side and the lower side of the crimping edge are respectively provided with a metal sealing ring; the upper sealing flange and the lower sealing flange are respectively arranged on the upper side and the lower side of the crimping edge.
2. The low-loss high-vacuum-seal heat-insulation transmission window for the millimeter wave frequency band according to claim 1, characterized in that: the quartz layer is made of high-purity fused quartz material.
3. The low-loss high-vacuum-seal heat-insulation transmission window for the millimeter wave frequency band according to claim 1, characterized in that: the heat insulation layer is made of polystyrene foam.
4. The low-loss high-vacuum-seal heat-insulation transmission window for the millimeter wave frequency band according to claim 1, characterized in that: the heat insulation layer is provided with a plurality of through holes.
5. The low-loss high-vacuum-sealing heat-insulation transmission window for the millimeter wave frequency band according to claim 1, characterized in that: and the sealed upper flange and the sealed lower flange are both provided with stress grooves.
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| CN108448209B (en) * | 2018-04-25 | 2023-08-22 | 中国科学院国家天文台 | Multi-layer polyimide film vacuum window structure for radio frequency front end refrigeration Dewar |
| CN108808178A (en) * | 2018-06-19 | 2018-11-13 | 中国科学院新疆天文台 | A kind of spherical vacuum microwave window |
| CN108933069B (en) * | 2018-08-10 | 2020-06-23 | 安徽华东光电技术研究所有限公司 | Energy transmission window for transmitting terahertz waves |
| CN110994081B (en) * | 2019-12-31 | 2021-09-21 | 华南理工大学 | Wide-band compact waveguide dielectric window |
| CN113619768B (en) * | 2021-07-15 | 2023-08-18 | 山东工业陶瓷研究设计院有限公司 | High-reliability ceramic heat insulation window assembly and assembly method thereof |
| CN114986997B (en) * | 2022-04-22 | 2023-09-05 | 哈尔滨玻璃钢研究院有限公司 | Wave-transparent window with fixed-thickness fabric foam curved surface structure and assembling method |
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| CN201390780Y (en) * | 2008-11-15 | 2010-01-27 | 张敬祎 | Microwave vacuum metal coating device |
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| US5610567A (en) * | 1994-04-25 | 1997-03-11 | Southeastern Universities Research Assn., Inc. | Superconducting radiofrequency window assembly |
| US5532462A (en) * | 1994-04-29 | 1996-07-02 | Communications & Power Industries | Method of and apparatus for heating a reaction vessel with microwave energy |
| US8125402B2 (en) * | 2008-01-08 | 2012-02-28 | Raytheon Company | Methods and apparatus for multilayer millimeter-wave window |
| GB0900153D0 (en) * | 2009-01-06 | 2009-02-11 | E2V Tech Uk Ltd | Output window |
| CN104638320B (en) * | 2015-02-10 | 2018-04-27 | 中国电子科技集团公司第十六研究所 | Heavy caliber low-loss microwave vacuum window |
| CN204652707U (en) * | 2015-04-29 | 2015-09-16 | 昆明理工大学 | A kind of seal chamber microwave introduction device |
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| CN201390780Y (en) * | 2008-11-15 | 2010-01-27 | 张敬祎 | Microwave vacuum metal coating device |
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