A method for designing a telemetry subantenna in a close-in rotating antenna group

Abstract

This application provides a telemetry quantum antenna design method for a close-range rotating antenna array, belonging to the field of aero-engine technology. The method includes: determining the operating frequency range and maximum radius of the stator antenna installation location; determining the center frequency and free-space wavelength based on the frequency range; determining the radius range of the loop microstrip antenna based on the center frequency and maximum radius; determining the antenna width based on the characteristic impedance of the loop microstrip antenna; determining the antenna aperture angle based on the antenna radius and aperture gap; determining the loop microstrip antenna based on the antenna width, substrate thickness, antenna radius, and antenna aperture angle, and placing a ground plane below the substrate where the loop microstrip antenna is located; feeding the antenna with a coaxial cable at one end and connecting an RF resistor in series at the other end, with the other end of the RF resistor grounded, ultimately forming the telemetry quantum antenna. This solution reduces dependence on high coaxiality and the risk of instantaneous data packet loss, provides reliable RF reception, and improves engineering applicability.

Description

Technical Field

[0001] This application relates to the field of aero-engine technology, and in particular to a method for designing a telemetry quantum antenna in a close-range rotating antenna array. Background Technology

[0002] In the aviation industry, the development and mass production of aircraft and aero-engines must go through critical stages such as scientific research flight testing, bench testing, and airworthiness certification. Compared to the airborne equipment on aircraft, the core components of aero-engines are constantly in a state of high-speed rotation. During continuous operation, they are extremely prone to failure, which can not only lead to equipment damage but also seriously affect the research and development progress and production efficiency, causing significant economic losses and even serious consequences such as casualties. Therefore, it is necessary to conduct real-time and reliable telemetry of the dynamic parameters (such as temperature and stress) of rotating components to ensure the safe and reliable operation of rotating machinery.

[0003] Telemetry antennas, as key components that convert electrical signals into free-space electromagnetic waves, are a core part of telemetry systems for high-speed rotating components of aero-engines. Currently, parameter testing of aero-engine rotating components faces multiple challenges, such as: the installation space at the shaft end of the rotating component is often very limited; the rotor-to-stationary distance dynamically changes with engine operating conditions (typically ranging from 2.0 mm to 6.0 mm); and there is strong vibration and complex electromagnetic coupling interference. Especially in multi-parameter, multi-measurement-point testing scenarios, the receiver needs to receive signals transmitted from multiple transmitting antennas simultaneously through a single loop microstrip antenna. However, traditional resonant antennas have narrow bandwidths, are sensitive to spacing changes, and are prone to rotational coupling fluctuations due to standing wave nodes, making it difficult to meet the telemetry reception requirements of multi-channel, wide-band, and variable operating conditions.

[0004] In existing technologies, the design of loop traveling wave antennas relies heavily on experience, and a complete set of engineering design methods has not yet been established. This makes it difficult to achieve fast and reliable antenna design under extreme conditions such as high speed of aero engines, variable spacing, and limited space. Summary of the Invention

[0005] To address the issue of insufficient bandwidth when telemetry stator antennas simultaneously receive signals from multiple microstrip transmitting antennas, and to ensure stable and reliable operation of stator antennas under complex conditions of high-speed rotation of aero-engines and dynamic changes in the rotor-to-stationary distance, this application provides a telemetry stator antenna design method for a close-range rotating antenna array.

[0006] This application provides a method for designing a telemetry quantum antenna in a close-range rotating antenna array, including: Determine the application conditions of the designed stator antenna at the shaft end of the rotating component of the aero-engine, including the frequency range in which the stator antenna operates and the maximum radius of the stator antenna installation position; Determine the center frequency and free space wavelength based on the operating frequency range of the stator antenna; The radius range of the loop microstrip antenna is determined based on the center frequency and the maximum radius of the stator antenna mounting position. The width of the loop microstrip antenna is determined based on its characteristic impedance. Determine the opening angle of the loop microstrip antenna based on its radius and the opening gap. Based on the width of the loop microstrip antenna, the thickness of the substrate, the radius of the loop microstrip antenna, and the opening angle of the loop microstrip antenna, a loop microstrip antenna is constructed, and a ground plane is arranged below the substrate where the loop microstrip antenna is located, with the size of the ground plane covering the entire loop area. A coaxial cable is used to feed one end of a defined loop microstrip antenna, and an RF resistor is connected in series at the other end. The other end of the RF resistor is grounded, thus forming a telemetry quantum antenna.

[0007] According to a specific implementation of an embodiment of this application, the formula for calculating the center frequency is as follows: , Where f0 is the center frequency, f min f represents the lowest operating frequency in the frequency range in which the stator antenna operates. max This indicates the highest operating frequency within the frequency range in which the stator antenna operates.

[0008] According to a specific implementation of this application, the formula for calculating the free space wavelength is as follows: , Where λ0 represents the wavelength in free space, and c is the speed of light.

[0009] According to a specific implementation of an embodiment of this application, the radius of the ring microstrip antenna ranges as follows: , Where R is the radius of the loop microstrip antenna, R max This represents the maximum radius of the stator antenna mounting location.

[0010] According to a specific implementation of an embodiment of this application, determining the width of the loop microstrip antenna based on the characteristic impedance of the loop microstrip antenna includes: The impedance coefficient of the loop microstrip antenna is determined based on the characteristic impedance of the loop microstrip antenna and the relative permittivity of the substrate. Determine the aspect ratio of the loop microstrip antenna based on its impedance coefficient. The width of the ring microstrip antenna is determined based on its aspect ratio and substrate thickness.

[0011] According to a specific implementation of this application, the formula for calculating the impedance coefficient of the ring microstrip antenna is as follows: , Where Z0 is the characteristic impedance of the loop microstrip antenna, A is the impedance coefficient of the loop microstrip antenna, and ε r is the relative permittivity of the substrate.

[0012] According to a specific implementation of this application, the formula for calculating the aspect ratio of the loop microstrip antenna is as follows: , Where k is the aspect ratio of the ring microstrip antenna.

[0013] According to a specific implementation of this application, the formula for calculating the width of the ring microstrip antenna is as follows: W=kh, Where W is the width of the loop microstrip antenna and h is the thickness of the substrate.

[0014] According to a specific implementation of this application, the formula for calculating the aperture angle of the loop microstrip antenna is as follows: , Where G is the opening gap, θ gap The aperture angle of the loop microstrip antenna is given.

[0015] According to one specific implementation of this application, the resistance value of the radio frequency resistor is 50Ω.

[0016] Beneficial effects: The telemetry stator antenna design method in the close-range rotating antenna array of this application, through broadband matching characteristics and small-size opening gap design, makes the stator antenna insensitive to changes in the rotor-to-station distance (not greater than 15mm) when the rotation speed is no greater than 20,000 rpm. This fully adapts to the dynamic changes in rotor-to-station distance caused by vibration and other factors during actual operation of aero-engines, significantly reduces the dependence on high coaxiality, and improves the system's engineering applicability under complex mechanical conditions.

[0017] By constructing a loop microstrip antenna and connecting a 50Ω RF resistor in series at its end to ground, a traveling wave state is formed, which improves the impedance bandwidth and avoids the coupling attenuation problem caused by the fixed current node of the traditional resonant antenna. When the stator antenna can rotate in the full range of 0° to 360°, it always maintains a stable and continuous signal reception capability, and completely eliminates the risk of instantaneous data packet loss caused by rotating to the standing wave node.

[0018] This method provides reliable radio frequency reception for the synchronous wireless monitoring of multiple physical quantities such as rotor temperature and stress of aero-engines, supports online radio frequency transmission with high bandwidth for multiple parameters, and significantly improves the reliability and accuracy of engine health status assessment, fault warning and airworthiness verification. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart illustrating a telemetry quantum antenna design method in a close-range rotating antenna array according to an embodiment of the present invention. Detailed Implementation

[0021] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0022] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0024] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0025] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0026] In one embodiment, this application provides a method for designing a telemetry quantum antenna in a close-range rotating antenna array, referring to... Figure 1 This includes the following steps: S1. Determine the application conditions of the designed stator antenna at the shaft end of the rotating component of the aero-engine, including the frequency range in which the stator antenna operates. The maximum radius R of the stator antenna mounting position max ; S2. Determine the center frequency and free space wavelength based on the operating frequency range of the stator antenna; S3. Determine the radius range of the loop microstrip antenna based on the center frequency and the maximum radius of the stator antenna installation position; S4. Determine the width of the loop microstrip antenna based on its characteristic impedance. S5. Determine the opening angle of the loop microstrip antenna based on its radius and opening gap. S6. Determine the ring microstrip antenna based on the width of the ring microstrip antenna, the thickness of the substrate, the radius of the ring microstrip antenna, and the opening angle of the ring microstrip antenna. Arrange a ground plane below the substrate where the ring microstrip antenna is located, and the size of the ground plane covers the entire ring area. S7. A coaxial cable is used to feed one end of the determined loop microstrip antenna, and an RF resistor is connected in series at the other end. The other end of the RF resistor is grounded, thus forming a telemetry quantum antenna.

[0027] In this embodiment, the telemetry stator antenna designed through the above steps can be adapted to the narrow installation space at the shaft end of the rotating component of the aero-engine, maintaining stable radiation performance within the set operating frequency range. When the stator antenna and the rotor antenna are combined to form a rotating antenna group, stable telemetry signal transmission can be achieved while the rotor is continuously rotating. This satisfies the installation size limitations while ensuring the efficiency and reliability of signal transmission, providing stable hardware support for remote monitoring of the aero-engine's operating status.

[0028] Furthermore, the formula for calculating the center frequency is: , Where f0 is the center frequency, f min f represents the lowest operating frequency in the frequency range in which the stator antenna operates. max This indicates the highest operating frequency within the frequency range in which the stator antenna operates.

[0029] Specifically, considering the symmetrical antenna performance at the frequency band boundaries, that is: , Cross-multiplication yields: , , Physical meaning: When using the geometric mean center frequency, in and When the electrical length deviations at each point are equal, the change in the real part of the antenna's input impedance is minimal.

[0030] Furthermore, the formula for calculating the free space wavelength is as follows: , Where λ0 represents the wavelength in free space, and c is the speed of light.

[0031] Furthermore, the radius of the ring microstrip antenna ranges as follows: , Where R is the radius of the loop microstrip antenna, R max This represents the maximum radius of the stator antenna mounting location.

[0032] Specifically, regarding the left boundary of the radius range for a loop microstrip antenna: Radiation resistance R of a loop antenna r Approximately:

[0033] Where C is the circumference of the annulus; When R = λ0 / (8π), substituting the circumference of the annulus C = 2πR, we have: , At this point, the ring circumference is only one-quarter of the wavelength, and the radiation resistance is approximately: , Physical meaning: If R is less than λ0 / (8π), the radiation resistance is too low (<1Ω), which is seriously mismatched with the 50Ω feed line. The antenna efficiency is extremely low, and most of the power will be reflected back. Therefore, R must be greater than or equal to λ0 / (8π).

[0034] The physical meaning of the right boundary of the radius range for a loop microstrip antenna is as follows: Ensure that there is a safe distance between the edge of the stator antenna and the structure on which the stator antenna is installed, and also ensure that the coaxial power connector has space to be installed when power is supplied.

[0035] Furthermore, determining the width of the loop microstrip antenna based on its characteristic impedance includes: The impedance coefficient of the loop microstrip antenna is determined based on the characteristic impedance of the loop microstrip antenna and the relative permittivity of the substrate. Determine the aspect ratio of the loop microstrip antenna based on its impedance coefficient. The width of the ring microstrip antenna is determined based on its aspect ratio and substrate thickness.

[0036] In practical implementation, the characteristic impedance of the loop microstrip antenna is Z0 = 50Ω, and W / h ≤ 2; an FR4 dielectric substrate is selected, and the relative permittivity of the substrate is ε. r =4.4.

[0037] Furthermore, the formula for calculating the impedance coefficient of the ring microstrip antenna is as follows: , Where Z0 is the characteristic impedance of the loop microstrip antenna, A is the impedance coefficient of the loop microstrip antenna, and ε r is the relative permittivity of the substrate.

[0038] Furthermore, the formula for calculating the aspect ratio of the ring microstrip antenna is as follows: , Where k is the aspect ratio of the ring microstrip antenna.

[0039] Furthermore, the formula for calculating the width of the ring microstrip antenna is as follows: W=kh, Where W is the width of the ring microstrip antenna and h is the thickness of the substrate. The calculated width W of the ring microstrip antenna is retained to one decimal place.

[0040] Specifically, the calculation of the impedance coefficient of a loop microstrip antenna includes the following: Effective dielectric constant ε eff This can be expressed as: , Taking the square root of both sides, we get: , make: , , Where a is the first intermediate quantity, b is the second intermediate quantity, and t is the third intermediate quantity. but: , when When within range, Performing a first-order Taylor expansion, we get: , then, , Because in When within the range, t is a number between 0 and 1.

[0041] Let the fourth intermediate quantity x = 12 / k, then Using a first-order Taylor expansion, we get: , pair a Differentiate: , For all denominator Since numerator 2 > 0, therefore, Constant is positive, a is It is a strictly monotonically increasing function.

[0042] a·t is not always much less than 1, so direct expansion results in a large error. We retain the expansion form but replace the coefficients with undetermined parameters p: , Where p is an undetermined fitting coefficient.

[0043] exist When within range, The value of is in Between, approximately Fluctuating up and down.

[0044] Define the first constant Substitute We can obtain: , Will Combined into a second constant We can obtain: , The impedance coefficient of a loop microstrip antenna can be expressed as: when , , Retaining only the part containing k on the right side of the above equation, it can be transformed into: , when , , Similarly, the above formula can be transformed into: , Based on the above description, The impedance coefficient of a loop microstrip antenna is defined as: , In order to The situation is similar; construct an A, therefore, construct a , The solution to this equation is: , Taking the natural logarithm of both sides of the above solution, we get: , √ item Transformed into: , By expanding the binomial and taking a first-order approximation, we can obtain: , therefore, , Substituting the above approximation We can obtain: , Taking the logarithm, we get: , At this point, it can be observed that, and The right side of the middle is consistent. , Therefore, in Within the range, A can be expressed as: , Will Substituting into the above equation, we get: , Will and Substituting into the above equation, we get: , The second item Merge into one about Functions: , make: , but: , right Perform engineering fitting and search and , so that: , for The typical conditions, after least squares fitting, yield the following: , therefore, , Will Substitute the fitting results into: , Furthermore, the formula for calculating the aperture angle of the ring microstrip antenna is as follows: , Where G is the opening gap, θ gap The aperture angle G of the loop microstrip antenna is preferably 3~5mm.

[0045] In one embodiment, the resistance of the radio frequency resistor is 50Ω.

[0046] The following is a specific example illustrating the steps: S1. Determine the application conditions of the designed stator antenna at the shaft end of the rotating component of the aero-engine; S1.1 Determine the operating frequency range of the stator antenna. ; S1.2 Determine the maximum radius of the stator antenna installation position. ; S2. Determine the center frequency f0 and free space wavelength λ0, specifically: S2.1 Calculate the center frequency f0: ; S2.2 Calculate the free space wavelength λ0: , Where c represents the speed of light; S3. Determine the range of values ​​for the radius R of the loop microstrip antenna: , , , therefore, In this embodiment, we select ; S4. Determine the loop microstrip line width W based on the characteristic impedance Z0 of the loop microstrip antenna. Generally, the characteristic impedance of a loop microstrip antenna is Z0 = 50Ω, and W / h ≤ 2; an FR4 dielectric substrate is selected, with a relative permittivity ε. r =4.4; S4.1 Calculate the impedance coefficient A of the loop microstrip antenna: , Where, ε r The relative permittivity of the substrate; S4.2 Calculate the aspect ratio k of the loop microstrip antenna: ; S4.3. Based on the range of processable substrate thickness h, select substrate thickness h = 1.6 mm, and calculate W: , Take W = 3.1 mm; S5. Determine the aperture angle θ of the loop microstrip antenna. gap :

[0047] S6. Based on the loop microstrip antenna width W, substrate thickness h, and loop microstrip antenna radius R, the aperture angle θ gap A loop microstrip antenna is determined, and a ground plane is arranged below the substrate where the loop microstrip antenna is located, with the size of the ground plane covering the entire loop area. S7. One end of the loop microstrip antenna determined in S6 is fed by a coaxial line, and a radio frequency resistor is connected in series at the other end. The other end of the radio frequency resistor is grounded to form a telemetry quantum antenna. Preferably, the RF resistor has a resistance of 50Ω.

[0048] The core principle of the embodiments provided in this application is as follows: By analyzing the installation environment conditions of the telemetry stator antenna on the stator component at the shaft end of the aero-engine rotating part, and the complex high-speed rotation conditions under which the rotating part's rotation speed does not exceed 20,000 rpm and the dynamic variation of the rotor-to-stationary distance (typically ranging from 2.0 to 6.0 mm), combined with the operating frequency range of the telemetry system, a design method for a loop microstrip antenna is proposed. One end of the loop microstrip antenna is used as the feed port, and the other end is connected in series with a 50Ω RF resistor and grounded. When the RF signal is injected from the feed end, the electromagnetic wave propagates along the loop microstrip antenna. Since the impedance of the terminating resistor matches the characteristic impedance of the loop microstrip antenna, the electromagnetic wave propagating to the terminal is absorbed by the resistor, thereby forming a traveling wave state on the loop antenna. This constitutes a stator antenna whose impedance bandwidth can completely cover the operating frequency range of the telemetry system, providing a reliable guarantee for high-fidelity reception of telemetry signals from the rotating part.

[0049] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for designing a telemetry quantum antenna in a close-range rotating antenna array, characterized in that, include: Determine the application conditions of the designed stator antenna at the shaft end of the rotating component of the aero-engine, including the frequency range in which the stator antenna operates and the maximum radius of the stator antenna installation position; Determine the center frequency and free space wavelength based on the operating frequency range of the stator antenna; The radius range of the loop microstrip antenna is determined based on the center frequency and the maximum radius of the stator antenna mounting position. The width of the loop microstrip antenna is determined based on its characteristic impedance. Determine the opening angle of the loop microstrip antenna based on its radius and the opening gap. The ring microstrip antenna is determined based on its width, substrate thickness, radius, and aperture angle. A ground plane is then placed below the substrate where the ring microstrip antenna is located, with the ground plane covering the entire ring area. A coaxial cable is used to feed one end of a defined loop microstrip antenna, and an RF resistor is connected in series at the other end. The other end of the RF resistor is grounded, thus forming a telemetry quantum antenna.

2. The telemetry quantum antenna design method in a close-range rotating antenna array according to claim 1, characterized in that, The formula for calculating the center frequency is: ， Where f0 is the center frequency, f min f represents the lowest operating frequency in the frequency range in which the stator antenna operates. max This indicates the highest operating frequency within the frequency range in which the stator antenna operates.

3. The telemetry quantum antenna design method in a close-range rotating antenna array according to claim 2, characterized in that, The formula for calculating the free space wavelength is: ， Where λ0 represents the wavelength in free space, and c is the speed of light.

4. The telemetry quantum antenna design method in a close-range rotating antenna array according to claim 3, characterized in that, The radius of the ring microstrip antenna ranges as follows: ， Where R is the radius of the loop microstrip antenna, R max This represents the maximum radius of the stator antenna mounting location.

5. The telemetry quantum antenna design method in a close-range rotating antenna array according to claim 4, characterized in that, The step of determining the width of the loop microstrip antenna based on its characteristic impedance includes: The impedance coefficient of the loop microstrip antenna is determined based on the characteristic impedance of the loop microstrip antenna and the relative permittivity of the substrate. Determine the aspect ratio of the loop microstrip antenna based on its impedance coefficient. The width of the ring microstrip antenna is determined based on its aspect ratio and substrate thickness.

6. The telemetry quantum antenna design method in a close-range rotating antenna array according to claim 5, characterized in that, The formula for calculating the impedance coefficient of the ring microstrip antenna is as follows: ， Where Z0 is the characteristic impedance of the loop microstrip antenna, A is the impedance coefficient of the loop microstrip antenna, and ε r is the relative permittivity of the substrate.

7. The telemetry quantum antenna design method in a close-range rotating antenna array according to claim 6, characterized in that, The formula for calculating the aspect ratio of the ring microstrip antenna is as follows: ， Where k is the aspect ratio of the ring microstrip antenna.

8. The telemetry quantum antenna design method in a close-range rotating antenna array according to claim 7, characterized in that, The formula for calculating the width of the ring microstrip antenna is as follows: W=kh, Where W is the width of the loop microstrip antenna and h is the thickness of the substrate.

9. The telemetry quantum antenna design method in a close-range rotating antenna array according to claim 4, characterized in that, The formula for calculating the aperture angle of the ring microstrip antenna is as follows: ， Where G is the opening gap, θ gap The aperture angle of the loop microstrip antenna is given.

10. The method for designing a telemetry quantum antenna in a close-range rotating antenna array according to any one of claims 1-9, characterized in that, The resistance of the RF resistor is 50Ω.

Images