A YIG filter anti-radiation additional shielding structure and a filter with the additional shielding structure

Abstract

The invention discloses an additional anti-radiation shielding structure for a YIG filter, belonging to the technical field of anti-radiation reinforcement of electronic components, comprising an upper shielding cylinder and a lower shielding cylinder which are symmetrical in upper and lower directions, wherein the upper shielding cylinder and the lower shielding cylinder are provided with bottom through holes at the same position on the bottom, the side walls where the upper shielding cylinder and the lower shielding cylinder are connected are provided with side wall notches, and the side walls of the upper shielding cylinder and the lower shielding cylinder are also provided with side wall through holes; the invention also discloses a filter with the additional shielding structure; the invention provides an additional anti-radiation shielding structure for a YIG filter, which is beneficial to enhancing the anti-space radiation capability of the YIG filter, enabling the YIG filter to withstand more severe space radiation and maintain stable working performance, thereby extending its service life in a space radiation environment.

Description

Technical Field

[0001] The invention relates to the technical field of radiation-resistant reinforcement of electronic components, and in particular to an additional radiation-resistant shielding structure for a YIG filter and a filter with the additional shielding structure. Background Art

[0002] The YIG filter is a device with microwave gyromagnetic material (such as yttrium iron garnet, YIG) as the core. It has the characteristics of broadband tuning and high suppression. Its operating frequency can be continuously adjusted within a wide band (up to several octaves). It is mainly used in microwave testing, communication, radar, electronic countermeasures and other systems.

[0003] The existing conventional YIG filter does not specifically consider the radiation hardening design. Its typical structure is as follows Figure 1 As shown, it includes an upper magnetic circuit 1, an upper pole 2 of the upper magnetic circuit, an upper driving coil 3 installed in the upper magnetic circuit, a lower magnetic circuit 4, a lower pole 5 of the lower magnetic circuit, a lower driving coil 6 installed in the lower magnetic circuit, a YIG resonant circuit 7, a connector 8, and a coaxial cable 9 interconnecting the connector 8 and the YIG resonant circuit 7;

[0004] The magnetic circuit material of the YIG filter is an iron-nickel alloy. The conventional YIG filter mentioned above mainly relies on its own iron-nickel alloy "self-shielding" magnetic circuit structure to play an electromagnetic shielding role and has a certain radiation resistance. For example, protons, alpha particles and heavy ions have poor penetration and generally cannot directly penetrate the iron-nickel alloy layer and enter the filter.

[0005] However, gamma rays, X-rays and other photons have strong penetrating power, and the iron-nickel alloy layer of the YIG filter cannot effectively shield them; at the same time, protons, alpha particles, heavy ions and neutrons will react with the iron-nickel alloy to stimulate secondary radiation, such as gamma rays; rays and particles that pass through the iron-nickel alloy layer and enter the filter will cause displacement damage to the internal circuit materials, total ionization dose and other radiation effects, resulting in filter performance parameter drift, index deterioration, shortened life and other effects. Summary of the invention

[0006] One of the purposes of the present invention is to provide an additional anti-radiation shielding structure for a YIG filter to solve the above-mentioned problem.

[0007] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a YIG filter anti-radiation additional shielding structure, comprising an upper shielding cylinder and a lower shielding cylinder which are symmetrical in upper and lower directions, the upper shielding cylinder and the lower shielding cylinder are both provided with bottom through holes at the same position on the bottom, the side walls where the upper shielding cylinder and the lower shielding cylinder are connected are provided with side wall notches, and the side walls of the upper shielding cylinder and the lower shielding cylinder are also provided with side wall through holes.

[0008] As a preferred technical solution: the upper shielding cylinder and the lower shielding cylinder are both made of non-magnetic materials.

[0009] As a preferred technical solution: the upper shielding cylinder and / or the lower shielding cylinder is a single-layer or multi-layer structure.

[0010] As a further preferred technical solution: the upper shielding cylinder and / or the lower shielding cylinder is a multi-layer structure, and different layers are made of non-magnetic materials with different atomic numbers.

[0011] The original "self-shielding" magnetic circuit structure of the YIG filter is called a "built-in shielding layer", and the "shielding cylinder" composed of an upper shielding cylinder and a lower shielding cylinder newly added in this application is called an "additional shielding layer"; a "shielding cylinder" is added between the inner wall of the "self-shielding" magnetic circuit formed by the iron-nickel alloy and the driving coil to surround the driving coil, the resonant circuit, etc. inside;

[0012] The material used to make the "shielding tube" must be non-magnetic material, such as lead, molybdenum-copper alloy, aluminum, etc.

[0013] According to different design goals, the "shielding tube" can adopt a single-layer structure or a multi-layer structure composed of different materials to improve the shielding effectiveness; when a multi-layer "nesting doll" structure is adopted, different layers adopt non-magnetic materials with different atomic numbers (Z), generally a combination of high-Z and low-Z element materials, or an alloy. Whether the use of a multi-layer shielding structure can achieve a good effect is also related to the materials used and their combination order, and the comparison of Examples 1 and 2 below can further explain this.

[0014] The second object of the present invention is to provide a YIG filter, comprising an upper magnetic circuit, an upper pole of the upper magnetic circuit, an upper drive coil installed in the upper magnetic circuit, a lower magnetic circuit, a lower pole of the lower magnetic circuit, a lower drive coil installed in the lower magnetic circuit, a YIG resonant circuit, a connector, and a coaxial cable interconnecting the connector and the YIG resonant circuit, and also comprising the aforementioned additional radiation-resistant shielding structure, wherein the upper drive coil, the lower drive coil and the YIG resonant circuit are all located inside the additional radiation-resistant shielding structure surrounded by the upper shielding cylinder and the lower shielding cylinder, the upper pole and the lower pole both pass through the bottom through hole, the coaxial cable passes through the side wall notch, and the upper drive coil and lower drive coil terminals pass through the side wall through holes.

[0015] After adding the "shielding tube" structure of this application, it is necessary to modify the design of the original magnetic circuit or drive coil to leave space for the added "shielding tube", specifically:

[0016] Since the added "shielding tube" is sandwiched between the inner wall of the magnetic circuit and the driving coil in the structural space, the purpose of modifying the magnetic circuit or driving coil is to leave space for adding the "shielding tube". There are two modification options: 1) If the filter size is allowed to be expanded, the diameter and height of the inner cavity of the filter magnetic circuit are correspondingly expanded; 2) Reduce the number of turns of the driving coil to reduce the outer diameter and height of the coil. The second option will reduce the frequency tuning sensitivity of the YIG filter. Therefore, if necessary and allowed, the height of the magnetic circuit air gap can be reduced to keep the tuning sensitivity unchanged.

[0017] Compared with the prior art, the advantages of the present invention are: the present invention provides an additional shielding structure for YIG filter anti-radiation, which is beneficial to enhancing the YIG filter's ability to resist space radiation, enabling the YIG filter to withstand more severe space radiation while maintaining stable working performance, and extending its service life in a space radiation environment.

[0018] Specifically, the inventors simulated and counted the probability of photons penetrating the YIG filter shielding layer (a combination of the built-in shielding of the magnetic circuit and the additional shielding structure) using simulation software. The number of incident photons was 100,000, and the energy was evenly distributed between 0.01 MeV and 1 MeV. The probability statistics of photons penetrating the shielding layer are as follows: Fig. 9 As shown, the calculation results in the three cases are:

[0019] 1) The thickness of the iron-nickel alloy layer of the magnetic circuit is 2 mm. When there is no additional shielding, the probability of a photon with an energy of 0.2 MeV penetrating the shielding layer is about 0.409%, and the total probability of all photons penetrating the shielding layer is about 40.31%;

[0020] 2) When the thickness of the iron-nickel alloy layer of the magnetic circuit is 2 mm and the single-layer shielding structure of the present application is 2 mm thick lead, the probability of a photon with an energy of 0.2 MeV penetrating the shielding layer is about 0.038%, and the total probability of all photons penetrating the shielding layer is about 25.75%;

[0021] 3) When the thickness of the iron-nickel alloy layer of the magnetic circuit is 2 mm and the double-layer shielding structure of the present application is added, with the outer layer being 1 mm thick lead and the inner layer being 1 mm thick molybdenum-copper alloy (grade MoCu25), the probability of a photon with an energy of 0.2 MeV penetrating the shielding layer is approximately 0.114%, and the total probability of all photons penetrating the shielding layer is approximately 28.49%. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a cross-sectional view of an existing conventional YIG filter;

[0023] Figure 2 It is a top view (half-section) of an existing conventional YIG filter;

[0024] Figure 3is a cross-sectional view of the lower shielding cylinder of Example 1 of the present invention;

[0025] Figure 4 is a top view of the lower shielding cylinder of Example 1 of the present invention;

[0026] Figure 5 is a cross-sectional view of a complete shielding structure of Example 1 of the present invention;

[0027] Figure 6 is a cross-sectional view of the shielding structure and the YIG filter after being assembled according to Embodiment 1 of the present invention;

[0028] Figure 7 is a top view (half-section) of the shielding structure and the YIG filter after being assembled according to Embodiment 1 of the present invention;

[0029] Figure 8 is a cross-sectional view of a complete shielding structure of Example 2 of the present invention;

[0030] Fig. 9 It is the probability statistical curve of photons penetrating three different shielding structures.

[0031] In the figure: 1, upper magnetic circuit; 2, upper pole; 3, upper drive coil; 4, lower magnetic circuit; 5, lower pole; 6, lower drive coil; 7, YIG resonant circuit; 8, connector; 9, coaxial cable; 10, upper shielding cylinder; 11, lower shielding cylinder; 12, bottom through hole; 13, side wall notch; 14, side wall through hole; A, inner layer; B, outer layer. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings.

[0033] Embodiment 1:

[0034] See also Figure 3-4 , a YIG filter anti-radiation additional shielding structure, comprising an upper shielding cylinder 10 and a lower shielding cylinder 11 which are symmetrical in the upper and lower directions, wherein the upper shielding cylinder 10 and the lower shielding cylinder 11 are provided with a bottom through hole 12 at the same position at the bottom, and the side wall where the upper shielding cylinder 10 and the lower shielding cylinder 11 are connected is provided with a side wall notch 13, and the side wall of the upper shielding cylinder 10 and the lower shielding cylinder 11 is also provided with a side wall through hole 14; the upper shielding cylinder 10 and the lower shielding cylinder 11 of this embodiment are single-layer structures, and the two are assembled together to form a structure as shown in FIG. Figure 5 The structure shown,

[0035] The upper shielding cylinder 10 and the lower shielding cylinder 11 of this embodiment are both made of metal lead, and the shielding cylinder wall thickness is 2mm;

[0036] The above shielding structure is installed on the YIG filter, such as Figure 6 and7 As shown, the upper pole 2 and the lower pole 5 of the magnetic circuit pass through the bottom through holes 12 of the upper shielding cylinder 10 and the lower shielding cylinder 11 respectively; the coaxial cable 9 passes through the small hole formed by the side wall notches 13 of the upper shielding cylinder 10 and the lower shielding cylinder 11; the upper drive coil 3 terminal, the lower drive coil 6 and the heater terminal are led out from the side wall through hole 14.

[0037] The YIG filter using the shielding structure of this embodiment is simulated and statistically analyzed by software on the probability of photons penetrating the shielding layer of the YIG filter. Compared with the case without the additional shielding layer, the probability of photons with uniform energy between 0.01 MeV and 1 MeV penetrating the shielding layer using the single-layer shielding tube structure of Embodiment 1 is reduced from about 40.31% to about 25.75%. Fig. 9 (Note: The total probability is the integral of the curve in the figure over the horizontal axis, that is, the area enclosed by the curve and the horizontal axis).

[0038] This embodiment uses a single layer of lead with a thickness of 2 mm, which has the best total shielding effect on photon radiation in the energy range of 0.01 to 1 MeV; however, from the simulation data curve ( Fig. 9 ), there is a bulge in the range of 0.01 to 0.1 MeV, indicating that the shielding effect in the low energy range is not as good as the "outer layer 1 mm lead + inner layer 1 mm molybdenum copper alloy" in Example 2.

[0039] In addition, from the perspective of the service life of the YIG filter, since the service life is closely related to the radiation environment, its service life will definitely be extended due to the improvement of shielding effectiveness.

[0040] Embodiment 2:

[0041] Compared with the first embodiment, the upper shielding cylinder 10 and the lower shielding cylinder 11 of the present embodiment both adopt a double-layer structure. Figure 8 As shown, the inner layer A and the outer layer B are made of different materials. Specifically, the inner layer A is made of molybdenum-copper alloy material (grade MoCu25), and the outer layer B is made of lead material. The thickness of both is 1 mm, and the rest is the same as Example 1;

[0042] The YIG filter with the shielding structure of this embodiment is used to simulate and statistically analyze the probability of photons penetrating the shielding layer of the YIG filter through software. Compared with the case without the additional shielding layer, the probability of photons with uniform energy between 0.01 MeV and 1 MeV penetrating the shielding layer using the double-layer shielding tube structure of Example 2 is reduced from about 40.31% to about 28.49%. Fig. 9 .

[0043] Compared with Example 1, although the total shielding effectiveness of this embodiment for photon radiation with energy between 0.01MeV and 1MeV is slightly reduced, the shielding effect for photon radiation below 0.1MeV is better. Fig. 9 It can be seen that the photon penetration probability curve corresponding to Example 1 has an obvious bump below 0.1 MeV, while the penetration probability curve corresponding to Example 2 has no bump. This is related to the stopping power of the shielding material. Different materials have different stopping powers at different incident particle energies.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention, such as the number of layers, materials, thickness, etc. of the shielding tube, should be included in the protection scope of the present invention.

Claims

1. A YIG filter, comprising an upper magnetic circuit, an upper pole of the upper magnetic circuit, an upper drive coil installed in the upper magnetic circuit, a lower magnetic circuit, a lower pole of the lower magnetic circuit, a lower drive coil installed in the lower magnetic circuit, a YIG resonant circuit, a connector, and a coaxial cable interconnecting the connector and the YIG resonant circuit, characterized in that: It also includes an anti-radiation additional shielding structure, including an upper shielding cylinder and a lower shielding cylinder that are symmetrical in the upper and lower directions, the upper shielding cylinder and the lower shielding cylinder are both provided with bottom through holes at the same position on the bottom, the side walls where the upper shielding cylinder and the lower shielding cylinder meet are provided with side wall notches, and the side walls of the upper shielding cylinder and the lower shielding cylinder are also provided with side wall through holes; Wherein, the upper drive coil, the lower drive coil and the YIG resonant circuit are all located inside the anti-radiation additional shielding structure surrounded by the upper shielding cylinder and the lower shielding cylinder, the upper pole and the lower pole both pass through the bottom through hole, the coaxial cable passes through the side wall notch, and the upper drive coil and the lower drive coil terminals pass through the side wall through hole; The upper shielding cylinder and the lower shielding cylinder are both made of non-magnetic materials; The upper shielding cylinder and / or the lower shielding cylinder is a single-layer or multi-layer structure.

2. The YIG filter according to claim 1, characterized in that: The upper shielding cylinder and / or the lower shielding cylinder is a multi-layer structure, and different layers are made of non-magnetic materials with different atomic numbers.

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