A slide rule for fast calculation of electromagnetic wave attenuation in two-line propagation

Abstract

The present invention provides a slide rule for quickly calculating the attenuation of electromagnetic wave two-line propagation, including a Fresnel zone calculation tool and a two-line propagation attenuation calculation tool; a set of calculation tools for the attenuation of electromagnetic wave signal two-line propagation includes two calculation tools, which are respectively used to calculate the attenuation of two-line propagation signals and the Fresnel zone distance, wherein the Fresnel zone calculation tool is used to determine whether to apply a two-line propagation model to calculate the attenuation, and the two-line propagation attenuation calculation tool is used to calculate the specific attenuation value. Using this set of tools, the conditions for applying two-line propagation and the values ​​of the two-line propagation signal attenuation can be quickly determined. This set of tools can help combat support personnel save calculation time, quickly calculate which model to use to calculate the attenuation of signal propagation and the transmission power of the signal after two-line propagation, greatly improve efficiency, and have significant military benefits.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic wave two-line propagation attenuation calculation tools, and in particular to a slide rule for quickly calculating electromagnetic wave two-line propagation attenuation. Background Art

[0002] When performing reconnaissance or jamming missions, airborne combat personnel of electronic warfare aircraft need to quickly and accurately grasp the battlefield electromagnetic situation and target radiation source information. Among them, the transmission power of the target radiation source is an important information data, an important indicator reflecting the target type and state of the radiation source, and the basic data for combat personnel to adjust the receiver sensitivity and dynamic range. It is also an important information that is indispensable for formulating reconnaissance and jamming plans. According to the signal link transmission theory, the signal transmission power can be calculated by the signal receiving power and the signal attenuation in the link. The signal receiving power can be directly measured, while the signal attenuation in the link transmission needs to be calculated according to the formula. However, the process is complicated and time-consuming, which reduces work efficiency and does not meet the real-time and urgency requirements of combat personnel in performing tasks.

[0003] The propagation of electromagnetic waves in space mainly considers line-of-sight (free space) propagation and two-line propagation. The calculation tool for line-of-sight propagation has been successfully developed. When the transmitting antenna and receiving antenna of electromagnetic waves are close to a major reflecting surface (such as the ground or water surface), the two-line propagation model needs to be considered. The decision to use the two-line propagation model or the line-of-sight propagation model depends on the antenna height and the transmission frequency. The distance in the Fresnel zone needs to be calculated. The distance in the Fresnel zone is the distance between a certain position and the transmitter when the phase cancellation is more obvious than the diffusion loss.

[0004] According to the signal link transmission theory, the attenuation of electromagnetic wave signals propagating in space can be calculated in a computer by establishing a corresponding mathematical model. Software with this function is installed in the computer of the electronic warfare mission system.

[0005] However, the electronic warfare environment is dynamic in nature, and the signal environment changes rapidly and dramatically, which places high demands on the timeliness of calculations. It is necessary to quickly calculate the power of the current signal to be processed. However, it takes a certain amount of time to manually input the signal parameters into the computer to calculate the attenuation value, which does not meet the timeliness requirements. Summary of the invention

[0006] In view of this, the present invention provides a slide rule for quickly calculating the attenuation of two-line propagation of electromagnetic waves, which helps combat support personnel save calculation time and quickly calculate which model to use to calculate the attenuation of signal propagation and the transmission power of the signal after two-line propagation, thereby greatly improving efficiency and achieving significant military benefits.

[0007] In order to solve the above technical problems, the present invention provides a slide rule for quickly calculating the attenuation of two-line propagation of electromagnetic waves, including a Fresnel zone calculation tool and a two-line propagation attenuation calculation tool;

[0008] The Fresnel zone calculation tool comprises a first bottom plate, a first identification plate is arranged on the upper edge of the first bottom plate, a second identification plate is arranged on the lower edge of the first bottom plate, a first pull-out groove is formed between the first identification plate and the second identification plate, a first pull-out plate is arranged in the first pull-out groove, first upper plates are arranged at both ends of the first identification plate and the second identification plate, a first marker is arranged on the upper surface of one of the first upper plates, a first transmitting antenna height scale is arranged on the first identification plate, a first receiving antenna height scale is arranged on the upper edge of the first pull-out plate, a Fresnel zone scale is arranged on the lower edge of the first pull-out plate, and a frequency scale is arranged on the second identification plate;

[0009] The two-line propagation attenuation calculation tool includes a second bottom plate, a third identification plate is arranged on the upper edge of the second bottom plate, a fourth identification plate is arranged on the lower edge of the second bottom plate, a second pull-out groove is formed between the third identification plate and the fourth identification plate, a second pull-out plate is arranged in the second pull-out groove, second upper plates are arranged at both ends of the third identification plate and the fourth identification plate, a second marker is arranged on the upper surface of one of the second upper plates, a link distance scale is arranged on the third identification plate, a second transmitting antenna height scale is arranged on the upper edge of the second pull-out plate, a two-line propagation attenuation scale is arranged on the lower edge of the second pull-out plate, and a second receiving antenna height scale is arranged on the fourth identification plate.

[0010] Furthermore, a first guide groove is provided on the first bottom plate corresponding to the first pull-out plate, a first guide strip is provided on the first pull-out plate corresponding to the first guide groove, a second guide groove is provided on the second bottom plate corresponding to the second pull-out plate, and a second guide strip is provided on the second pull-out plate corresponding to the second guide groove.

[0011] Furthermore, a plurality of first threaded holes are provided through the first identification plate, the lower ends of the first threaded holes are in contact with the first pull-out plate, the first clamping bolts are provided in the first threaded holes, the first turntable is provided at the upper ends of the first clamping bolts, and the first turntable is provided with anti-slip patterns.

[0012] Furthermore, a plurality of second threaded holes are provided through the third identification plate, the lower ends of the second threaded holes are in contact with the second pull-out plate, second clamping bolts are provided in the second threaded holes, a second turntable is provided at the upper ends of the second clamping bolts, and anti-slip patterns are provided on the second turntable.

[0013] Furthermore, a first limiting groove is arranged on the first bottom plate, the axis of the first limiting groove is parallel to the axis of the first guide groove, a first limiting block is arranged on the first pull-out plate corresponding to the first limiting groove, and the end of the first limiting block extends out of the first limiting groove and a first stopper is arranged.

[0014] Furthermore, a second limiting groove is provided on the second bottom plate, the axis of the second limiting groove is parallel to the axis of the second guide groove, a second limiting block is provided on the second pull-out plate corresponding to the second limiting groove, the end of the second limiting block extends out of the second limiting groove and a second stopper is provided.

[0015] Furthermore, both ends of the first identification plate and the second identification plate extend out of the first bottom plate, the first upper plate is fixed to the first identification plate and the second identification plate by bolt connection, and the length of the first pull-out plate is greater than the length of the first bottom plate.

[0016] Furthermore, first anti-slip grooves are provided on the lower surfaces of both ends of the first pull-out plate.

[0017] Furthermore, both ends of the third identification plate and the fourth identification plate extend out of the second bottom plate, the second upper plate is fixed to the third identification plate and the fourth identification plate by bolt connection, and the length of the second pull-out plate is greater than the length of the second bottom plate.

[0018] Furthermore, second anti-slip grooves are provided on the lower surfaces of both ends of the second pull-out plate.

[0019] The beneficial effects of the above technical solution of the present invention are as follows:

[0020] The signal frequency and meaningful propagation distance in the actual use environment are considered to determine the parameter range. The parameters for calculating signal attenuation are reflected on the slide rule in the form of scales. The slide rule can be moved to quickly align with the corresponding parameter scale, so that the signal attenuation value can be directly read, which can greatly save calculation time and has significant timeliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a front view of the Fresnel zone slide rule of the present invention;

[0022] Figure 2 is a cross-sectional view of the Fresnel zone slide rule of the present invention;

[0023] Figure 3 It is the back view of the Fresnel zone slide rule of the present invention;

[0024] Figure 4 It is a front view of the dual-line propagation attenuation slide rule of the present invention;

[0025] Figure 5 It is a cross-sectional view of the dual-line propagation attenuation slide rule of the present invention;

[0026] Figure 6 It is the back view of the dual-line propagation attenuation slide rule of the present invention;

[0027] Figure 7 A scale plane diagram of the Fresnel zone slide rule of the present invention;

[0028] Figure 8 It is a scale plane diagram of the dual-line propagation attenuation slide rule of the present invention;

[0029] Fig. 9 It is the propagation path diagram of the direct wave and the transmitted wave of the electromagnetic wave of the present invention;

[0030] Fig.10 A graph showing the relationship between the antenna height and the true length of the scale of the present invention;

[0031] Fig.11 This is a relationship diagram between the link distance value and the scale distance of the present invention.

[0032] 1. First upper plate; 2. First marker; 3. First marker plate; 4. First guide groove; 5. First limiting groove; 6. First turntable; 7. First clamping bolt; 8. First threaded hole; 9. First pull-out plate; 10. First anti-skid groove; 11. Second marker plate; 12. First bottom plate; 13. First guide strip; 14. First limiting block; 15. First stop block; 16. Second upper plate; 17. Second marker; 18. Third marker plate; 19. Second guide groove; 20. Second limiting groove; 21. Second turntable; 22. Second clamping bolt; 23. Second threaded hole; 24. Second pull-out plate; 25. Fourth marker plate; 26. Second bottom plate; 27. Second guide strip; 28. Second limiting block; 29. ​​Second stop block; 30. Second anti-skid groove. DETAILED DESCRIPTION

[0033] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the following will be combined with the appended drawings of the embodiments of the present invention. Figure 1-11 , the technical scheme of the embodiment of the present invention is clearly and completely described. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0034] Embodiment 1

[0035] like Figure 1-11 As shown: a slide rule for quickly calculating the attenuation of electromagnetic wave two-line propagation, including a Fresnel zone calculation tool and a two-line propagation attenuation calculation tool;

[0036] The Fresnel zone calculation tool includes a first bottom plate 12, a first identification plate 3 is arranged on the upper edge of the first bottom plate 12, a second identification plate 11 is arranged on the lower edge of the first bottom plate 12, a first pull-out groove is formed between the first identification plate 3 and the second identification plate 11, a first pull-out plate 9 is arranged in the first pull-out groove, a first upper plate 1 is arranged at both ends of the first identification plate 3 and the second identification plate 11, a first marker 2 is arranged on the upper surface of one of the first upper plates 1, a first transmitting antenna height scale is arranged on the first identification plate 3, a first receiving antenna height scale is arranged on the upper edge of the first pull-out plate 9, a Fresnel zone scale is arranged on the lower edge of the first pull-out plate 9, and a frequency scale is arranged on the second identification plate 11;

[0037] The two-line propagation attenuation calculation tool includes a second bottom plate 26, a third identification plate 18 is arranged on the upper edge of the second bottom plate 26, a fourth identification plate 25 is arranged on the lower edge of the second bottom plate 26, a second pull-out groove is formed between the third identification plate 18 and the fourth identification plate 25, a second pull-out plate 24 is arranged in the second pull-out groove, second upper plates 16 are arranged at both ends of the third identification plate 18 and the fourth identification plate 25, a second marker 17 is arranged on the upper surface of one of the second upper plates 16, a link distance scale is arranged on the third identification plate 18, a second transmitting antenna height scale is arranged on the upper edge of the second pull-out plate 24, a two-line propagation attenuation scale is arranged on the lower edge of the second pull-out plate 24, and a second receiving antenna height scale is arranged on the fourth identification plate 25.

[0038] Specifically, the slide rule includes two separate slide rules, including a Fresnel zone calculation tool and a two-line propagation attenuation calculation tool. The two calculation tools have the same structure, but the scales on the identification plates and the meanings of the scales are different. The identification plate on the bottom plate squeezes the pull-out plate in the middle, and the pull-out plate can be pulled left and right to adjust the scale to perform calculations. The upper plate is used to connect the two identification plates together, and at the same time, the meaning of the scale is displayed through the identification object. The specific meaning of the scale is in Figure 7 and Figure 8 Displayed in.

[0039] In one embodiment of the present invention, Figure 1-8 As shown,

[0040] The first bottom plate 12 is provided with a first guide groove 4 corresponding to the first pull-out plate 9, the first pull-out plate 9 is provided with a first guide strip 13 corresponding to the first guide groove 4, the second bottom plate 26 is provided with a second guide groove 19 corresponding to the second pull-out plate 24, and the second pull-out plate 24 is provided with a second guide strip 27 corresponding to the second guide groove 19. The guide groove guides the pull-out plate.

[0041] According to one embodiment of the present invention, Figure 1-8 As shown,

[0042] A plurality of first threaded holes 8 are provided through the first identification plate 3, the lower ends of the first threaded holes 8 are in contact with the first pull-out plate 9, the first clamping bolts 7 are provided in the first threaded holes 8, the first turntable 6 is provided at the upper ends of the first clamping bolts 7, and the first turntable 6 is provided with anti-slip patterns.

[0043] A plurality of second threaded holes 23 are provided through the third identification plate 18 , the lower ends of the second threaded holes 23 are in contact with the second pull-out plate 24 , second clamping bolts 22 are provided in the second threaded holes 23 , a second turntable 21 is provided at the upper end of the second clamping bolts 22 , and anti-slip grooves are provided on the second turntable 21 .

[0044] The clamping bolts are mainly used to fix the pull-out plate. During the specific calculation, when the pull-out plate is pulled to a certain position, in order to prevent the pull-out plate from accidentally sliding away, the clamping bolts can be tightened to squeeze the pull-out plate to achieve temporary fixation.

[0045] According to one embodiment of the present invention, Figure 1-8 As shown,

[0046] A first limiting groove 5 is provided on the first bottom plate 12, and the axis of the first limiting groove 5 is parallel to the axis of the first guide groove 4. A first limiting block 14 is provided on the first pull-out plate 9 corresponding to the first limiting groove 5, and the end of the first limiting block 14 extends out of the first limiting groove 5 and is provided with a first stopper 15.

[0047] A second limiting groove 20 is provided on the second bottom plate 26 , and the axis of the second limiting groove 20 is parallel to the axis of the second guide groove 19 . A second limiting block 28 is provided on the second pull-out plate 24 corresponding to the second limiting groove 20 , and the end of the second limiting block 28 extends out of the second limiting groove 20 and is provided with a second stopper 29 .

[0048] The limit groove cooperates with the limit block to limit the moving position of the pull-out plate, thereby preventing the pull-out plate from being pulled out of the bottom plate. At the same time, a stopper is provided on the limit block, and the length of the limiter block is the thickness of the bottom plate, so that the pull-out plate can be closely attached to the bottom plate by the fixation of the stopper to avoid shaking. The limiter block and the stopper can be realized by a bolt structure.

[0049] In one embodiment of the present invention, Figure 1-8 As shown,

[0050] Both ends of the first identification plate 3 and the second identification plate 11 extend out of the first bottom plate 12, the first upper plate 1 is fixed to the first identification plate 3 and the second identification plate 11 by bolt connection, and the length of the first pull-out plate 9 is greater than the length of the first bottom plate 12. First anti-slip grooves 10 are provided on the lower surfaces of both ends of the first pull-out plate 9.

[0051] The two ends of the third identification plate 18 and the fourth identification plate 25 extend out of the second bottom plate 26, the second upper plate 16 is fixed to the third identification plate 18 and the fourth identification plate 25 by bolt connection, and the length of the second pull-out plate 24 is greater than the length of the second bottom plate 26. The lower surfaces of the two ends of the second pull-out plate 24 are provided with second anti-slip grooves 30.

[0052] The pull-out plate needs to be able to move left and right on the bottom plate, so the length of the pull-out plate should be greater than the length of the bottom plate, so that the pull-out plate can be touched by hand for operation. And the anti-slip groove at the end of the pull-out plate is a groove body, so that the end of the pull-out plate is protruding, which is convenient for applying pulling force.

[0053] When designing a slide rule, first establish a Fresnel zone calculation model.

[0054] The calculation of the Fresnel zone distance can be achieved by the following formula:

[0055] FZ=4πh T h R / λ

[0056] Where: FZ——Fresnel zone distance, unit: m

[0057] h T ——Transmitting antenna height, in m

[0058] h R ——Receiving antenna height, in m

[0059] λ——wavelength, unit: m

[0060] Secondly, a calculation model for the attenuation of electromagnetic wave double-line propagation is established.

[0061] The main loss of two-line propagation is the phase cancellation between the direct wave and the signal transmitted from the ground or water surface. The attenuation depends on the link distance and the height of the transmitting and receiving antennas from the ground or water surface. Fig. 9 .

[0062] The calculation formula for two-line propagation loss is:

[0063] L = 120 + 40log (d) - 20log (h T )-20log(h R )

[0064] Where: d - link distance, unit km

[0065] h T ——Transmitting antenna height, in m

[0066] h R ——Receiving antenna height, in m

[0067] L——Link loss

[0068] Design calculation tool structure

[0069] According to the calculation formula of Fresnel zone and two-line propagation attenuation, the calculation tool to be developed should be designed as a multi-layer linkage structure, including the scale values ​​of several main calculation parameters, and the parameters can be changed by moving the corresponding scales to complete the calculation of different parameters. The calculation tool should include several necessary main parts:

[0070] Fresnel Zone Calculation Tool

[0071] The height scale of the transmitting antenna takes into account the height range of the transmitting antenna in actual conditions. The height range is in units of m and is designed to be 0 to 5000 meters. The scale values ​​show a logarithmic variation pattern, and the scale values ​​are arranged from small to large.

[0072] The height scale of the receiving antenna takes into account the height range of the receiving antenna in actual conditions. The height range is in meters and is designed to be 0 to 5000 meters. The scale values ​​show a logarithmic variation pattern and are arranged from large to small.

[0073] The frequency scale should cover the main frequency bands of current radar and communication signal frequencies as well as the frequency bands that may produce two-line propagation. The scale values ​​should show a logarithmic variation pattern and be designed to be 10MHz to 5000MHz, with the scale values ​​arranged from large to small.

[0074] The Fresnel zone scale is in km. Considering the actual possible distance range, it is designed to be 100 meters to 1000 kilometers. The scale values ​​show a logarithmic change pattern and are arranged from large to small.

[0075] The overall plan of the Fresnel zone calculation tool is as follows Figure 7 As shown, the transmitting antenna height scale and the frequency scale are fixed structures, and the receiving antenna height scale and the Fresnel zone scale are linked structures, which can be moved left and right according to the needs of calculation.

[0076] Two-line propagation attenuation calculation tool

[0077] The link distance scale is in km. Considering the actual possible distance range, it is designed to be 1 km to 1000 km. The scale values ​​show a logarithmic change pattern, and the scale values ​​are arranged from small to large.

[0078] The height scale of the transmitting antenna takes into account the height range of the transmitting antenna in actual conditions. The height range is in units of m and is designed to be 0 to 5000 meters. The scale values ​​show a logarithmic variation pattern, and the scale values ​​are arranged from small to large.

[0079] The height scale of the receiving antenna takes into account the height range of the receiving antenna in actual conditions. The height range is in meters and is designed to be 0 to 5000 meters. The scale values ​​show a logarithmic variation pattern and are arranged from small to large.

[0080] The two-line propagation attenuation value scale is designed to be 10dB to 180dB, taking into account the practical attenuation value range. The scale values ​​show a linear change pattern, and the scale values ​​are arranged from small to large.

[0081] The overall plan view of the two-line propagation attenuation slide rule is as follows Figure 8 The link distance scale and the receiving antenna height scale are fixed structures; the transmitting antenna height scale and the two-line propagation attenuation scale are linkage structures and can be moved left and right according to the calculation needs.

[0082] Determination of the measurement range and accuracy of the transmitting antenna height and receiving antenna height

[0083] The selection of the measurement range and accuracy of the transmitting antenna height and the receiving antenna height mainly considers the following factors, including the measurement requirements of the antenna height in the actual battlefield environment, the size requirements based on portability, and the engineering implementation requirements.

[0084] In the selection of antenna height range, considering the actual antenna height requirements, an antenna height measurement range of 1 meter to 5000 meters was selected as the slide rule. This antenna height range basically covers the actual requirements of the transmitting antenna height and the receiving antenna height in the battlefield.

[0085] Determining the accuracy is a difficult point in the design of the slide rule. The measurement accuracy is reflected in the design of the slide rule as the selection of specific scale values. According to the Fresnel zone and two-line propagation attenuation calculation formula, the attenuation value of the signal two-line propagation is linearly related to the common logarithm of the receiving antenna height, the transmitting antenna height, and the link distance. Therefore, the scale intervals of the transmitting antenna height and the receiving antenna height are both unequal and discontinuous scales. The frequency value must be converted to the actual distance of the scale on the slide rule in order to proceed to the next step of processing and production.

[0086] Based on the consideration of engineering realization and portability, the length of the link distance scale of 1 km to 10 km is selected as 5 cm as the reference length of the scale. The actual position of the scale values ​​of all other parameters on the slide rule is calculated based on this reference. Under this condition, combined with the attenuation value calculation formula, the following formula for determining the scale distance of the receiving antenna height and the transmitting antenna height can be derived:

[0087] d = 5 log 2 h / log 2 100

[0088] in:

[0089] h is the antenna height (displayed value), in meters;

[0090] d is the actual distance between the scale corresponding to a certain height value h and the "0 point" (1 meter scale) on the ruler, in cm.

[0091] The actual distance between two adjacent scales:

[0092] Δd=d 2 -d 1 =5 log 2 h 2 / log 2 100-5 log 2 h 1 / log 2 100

[0093] d 2 and d 1 is the actual distance between two adjacent scales, h 2 and h 1 are the height values ​​of two adjacent antennas.

[0094] According to the above two formulas, the positions of all scales on the transmitting antenna height and receiving antenna height scale can be determined. The specific scale calculation results are shown in Appendix 1, and the relationship between the scale distance and the frequency is shown in Fig.10 .

[0095] Determination of link distance range and measurement accuracy

[0096] Similarly, the main considerations for selecting the link distance range are the same as those for the antenna height. The measurement range of the link distance is selected as 1 km to 1000 km based on actual needs, which can meet the distance requirements between the actual aircraft and the radiation source during electronic warfare aircraft operations. The conversion method between the distance scale and the actual length on the slide rule is consistent with the frequency conversion method. The relationship between distance and attenuation is also consistent with the relationship between antenna height and attenuation. In order to shorten the length of the slide rule and take into account the logarithmic relationship between the scale value and the actual distance value, the greater the distance, the closer the interval between the scales. According to the determined reference length (the length of the link distance scale of 1 km to 10 km is 5 cm as the reference length of the scale), the formula for determining the scale distance of the link distance scale is:

[0097] d = 5 log 2 S / log 2 10

[0098] S is the link distance in km;

[0099] d is the actual distance between the scale corresponding to a certain distance value S and the "0 point" (1 km) on the ruler, in cm.

[0100] The actual distance between two adjacent scales:

[0101] Δd=d 2 -d 1 =5log 2 S 2 / log 2 10-5log 2 S 1 / log 2 10

[0102] According to the above two formulas, the positions of all scales on the link distance scale can be determined. The specific scale calculation results are shown in Appendix 2.

[0103] Determination of attenuation value range and scale value

[0104] According to the attenuation value calculation formula, the attenuation value is linearly related to the common logarithm of the frequency and link distance. Because the frequency and distance scales both use logarithmic scales, the scale values ​​on the attenuation scale change evenly and linearly. The base length of the link distance scale is 5 cm for 1 km to 1000 km. Under this condition, the value of each scale on the attenuation scale can be easily calculated. The specific values ​​are shown in Appendix 3.

[0105] Determination of the range and scale value of the transmitting antenna height and receiving antenna height of the Fresnel zone slide rule

[0106] The antenna height of the Fresnel zone slide rule is linearly related to the Fresnel zone distance. In order to unify the units and calculation methods of the entire set of calculation tools, the transmitting antenna and receiving antenna height scales of the Fresnel zone slide rule are the same as those of the two-line propagation attenuation slide rule, and are also set using linear laws. Therefore, the range and scale of the receiving antenna height and transmitting antenna height calculated in the Fresnel zone are exactly the same as those of the two-line propagation slide rule. The difference is that the height of the receiving antenna in the Fresnel zone slide rule is arranged from large to small. For specific values, see Appendix 4

[0107] Determination of the Frequency Scale and the Fresnel Zone Scale of the Fresnel Zone Slide Rule

[0108] Because the transmitting antenna and the receiving antenna adopt the logarithmic law, according to the calculation formula, the Fresnel zone distance and frequency values ​​should also change in the logarithmic law. The specific values ​​are determined according to the calculation formula, see Appendix 5 and Appendix 6.

[0109] Schedule 1

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[0112] Schedule 2

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[0115]

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[0117] Schedule 3

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[0122] Schedule 4

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[0126] Schedule 5

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[0131] Schedule 6

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[0134]

[0135] In the present invention, unless otherwise clearly stipulated and limited, for example, it can be a fixed connection, a detachable connection, or an integrated one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0136] The above is a preferred embodiment of the present invention. 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 invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A slide rule for rapidly calculating the attenuation of two-line electromagnetic wave propagation, characterized in that: Includes Fresnel zone calculation tool and two-line propagation attenuation calculation tool; The Fresnel zone calculation tool comprises a first bottom plate (12), a first identification plate (3) is arranged on the upper edge of the first bottom plate (12), a second identification plate (11) is arranged on the lower edge of the first bottom plate (12), a first draw-out groove is provided between the first identification plate (3) and the second identification plate (11), a first draw-out plate (9) is arranged in the first draw-out groove, first upper plates (1) are arranged at both ends of the first identification plate (3) and the second identification plate (11), a first marker (2) is arranged on the upper surface of one of the first upper plates (1), a first transmitting antenna height scale is arranged on the first identification plate (3), a first receiving antenna height scale is arranged on the upper edge of the first draw-out plate (9), a Fresnel zone scale is arranged on the lower edge of the first draw-out plate (9), and a frequency scale is arranged on the second identification plate (11); The two-line propagation attenuation calculation tool comprises a second bottom plate (26), a third identification plate (18) is arranged on the upper edge of the second bottom plate (26), a fourth identification plate (25) is arranged on the lower edge of the second bottom plate (26), a second draw-out groove is provided between the third identification plate (18) and the fourth identification plate (25), a second draw-out plate (24) is arranged in the second draw-out groove, second upper plates (16) are arranged at both ends of the third identification plate (18) and the fourth identification plate (25), a second marker (17) is arranged on the upper surface of one of the second upper plates (16), a link distance scale is arranged on the third identification plate (18), a second transmitting antenna height scale is arranged on the upper edge of the second draw-out plate (24), a two-line propagation attenuation scale is arranged on the lower edge of the second draw-out plate (24), and a second receiving antenna height scale is arranged on the fourth identification plate (25).

2. The slide rule for rapidly calculating the attenuation of two-line electromagnetic wave propagation as claimed in claim 1, characterized in that: A first guide groove (4) is provided on the first bottom plate (12) corresponding to the first drawable plate (9), a first guide strip (13) is provided on the first drawable plate (9) corresponding to the first guide groove (4), a second guide groove (19) is provided on the second bottom plate (26) corresponding to the second drawable plate (24), and a second guide strip (27) is provided on the second drawable plate (24) corresponding to the second guide groove (19).

3. The slide rule for rapidly calculating the attenuation of two-line electromagnetic wave propagation as claimed in claim 2, characterized in that: A plurality of first threaded holes (8) are provided through the first identification plate (3), the lower ends of the first threaded holes (8) are in contact with the first pull-out plate (9), a first clamping bolt (7) is provided in the first threaded hole (8), a first rotating disk (6) is provided at the upper end of the first clamping bolt (7), and anti-slip grooves are provided on the first rotating disk (6).

4. The slide rule for rapidly calculating the attenuation of two-line electromagnetic wave propagation as claimed in claim 2, characterized in that: A plurality of second threaded holes (23) are provided through the third identification plate (18), the lower ends of the second threaded holes (23) are in contact with the second pull-out plate (24), second clamping bolts (22) are provided in the second threaded holes (23), a second rotating disk (21) is provided at the upper ends of the second clamping bolts (22), and anti-slip grooves are provided on the second rotating disk (21).

5. The slide rule for rapidly calculating the attenuation of two-line electromagnetic wave propagation as claimed in claim 3, characterized in that: A first limiting groove (5) is provided on the first bottom plate (12), the axis of the first limiting groove (5) being parallel to the axis of the first guide groove (4), a first limiting block (14) is provided on the first pull-out plate (9) corresponding to the first limiting groove (5), the end of the first limiting block (14) extending out of the first limiting groove (5) and being provided with a first stopper (15).

6. The slide rule for rapidly calculating the attenuation of two-line electromagnetic wave propagation as claimed in claim 4, characterized in that: A second limiting groove (20) is provided on the second bottom plate (26), the axis of the second limiting groove (20) is parallel to the axis of the second guide groove (19), a second limiting block (28) is provided on the second pull-out plate (24) corresponding to the second limiting groove (20), the end of the second limiting block (28) protrudes out of the second limiting groove (20) and is provided with a second stopper (29).

7. The slide rule for rapidly calculating the attenuation of two-line electromagnetic wave propagation as claimed in claim 5, characterized in that: Both ends of the first identification plate (3) and the second identification plate (11) extend out of the first bottom plate (12); the first upper plate (1) is fixed to the first identification plate (3) and the second identification plate (11) by bolt connection; and the length of the first pull-out plate (9) is greater than the length of the first bottom plate (12).

8. The slide rule for rapidly calculating the attenuation of two-line electromagnetic wave propagation as claimed in claim 7, characterized in that: First anti-slip grooves (10) are provided on the lower surfaces of both ends of the first pull-out plate (9).

9. The slide rule for rapidly calculating the attenuation of two-line electromagnetic wave propagation as claimed in claim 6, characterized in that: Both ends of the third identification plate (18) and the fourth identification plate (25) extend out of the second bottom plate (26); the second upper plate (16) is fixed to the third identification plate (18) and the fourth identification plate (25) by bolt connection; and the length of the second pull-out plate (24) is greater than the length of the second bottom plate (26).

10. The slide rule for rapidly calculating the attenuation of two-line electromagnetic wave propagation as claimed in claim 9, characterized in that: Second anti-slip grooves (30) are provided on the lower surfaces of both ends of the second pull-out plate (24).

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