A method for maintaining the time-delay stability of an active phased array antenna

Abstract

This invention discloses a method for maintaining delay stability in an active phased array antenna, comprising two main parts: hardware design and software design. This invention effectively solves the system delay variation caused by angle scanning during electronic scanning of a phased array antenna. The hardware design mainly focuses on the topological structure design of the phased array antenna, enabling hardware implementation to support delay reference adjustment. The software design mainly involves the design of the antenna beam control algorithm, primarily used to adjust the delay reference based on different operating modes. This allows for antenna delay design tailored to different operational needs, ensuring no system delay jumps occur during antenna scanning. This invention enables a complete design process, resolving the problem of system delay jumps during the use of phased array antennas.

Description

Technical Field

[0001] This invention belongs to the field of phased array antenna development, specifically relating to a method for maintaining the delay stability of an active phased array antenna. Background Technology

[0002] Active phased array antennas are one of the most important components of phased array radar systems, and their scanning capability determines the performance of the radar system. With the continuous development of radar technology and breakthroughs in various new technologies, phased array radars are playing an increasingly important role in various radar system applications today. Taking Synthetic Aperture Radar (SAR) systems as an example, traditional SAR systems have strip imaging mode and spotlight imaging mode. Early SAR antennas could perform imaging without a phased array antenna. In strip mode, beam scanning was not required, while in spotlight mode, one-dimensional mechanical scanning of the radar itself could meet the needs of simple engineering applications. However, with the development of SAR technology and the increasing demands on SAR system capabilities, various operating modes such as ScanSAR, TOP mode, multi-angle mode, and multi-beam mode have emerged. These place more stringent requirements on the antenna's scanning capability, and the increasing demands on the SAR system's rapid response capability mean that traditional SAR systems using mechanical scanning can no longer meet the new application requirements. Therefore, the application of active phased array antennas with electronic scanning capabilities in SAR systems has become the only way to solve the current supply and demand imbalance.

[0003] SAR systems are self-coherent systems, and the time delay during imaging is a crucial data point in SAR operation, directly reflecting the distance between the target and the radar system. Therefore, the time delay stability of SAR systems is paramount. Traditional mechanically scanned SAR systems exhibit stable time delays during mechanical scanning, without any time delay fluctuations. However, for SAR systems using electronically scanned antenna arrays, time delay jumps caused by beam scanning, especially discontinuous scanning, can significantly impact imaging. While data compensation is commonly used in subsequent image processing, the characteristics of the time delay line mean that later data compensation cannot completely eliminate the impact. Therefore, designing a time-stable phased array antenna is of utmost importance.

[0004] In summary, designing a phased array antenna array with stable system delay is crucial for the operation of radar systems. This invention addresses this problem by employing both hardware and software design approaches to resolve the system delay jump issue caused by electronic scanning in phased array antennas. Summary of the Invention

[0005] The main objective of this invention is to provide a method for maintaining the stability of phased array antenna delay, thereby solving the problem of system delay jumps caused by electronic scanning in radar systems during electronic scanning, thus making the radar system's operating state more stable and improving system performance.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] A method for maintaining time-delay stability of an active phased array antenna includes the following steps:

[0008] Step 101: Estimate the antenna parameters according to the antenna's technical specifications;

[0009] Step 102: Design the antenna topology;

[0010] Step 103: Design a beam control algorithm to achieve delay stabilization of the phased array antenna.

[0011] Further, step 101 includes:

[0012] The technical specifications of the antenna include operating frequency, radiated power, beamwidth, and scanning capability. The antenna parameters include the antenna aperture, element spacing, number of channels, and power in the azimuth and range directions of the phased array antenna.

[0013] The azimuth and range spacing d of the antenna is determined by its scanning capability.

[0014]

[0015] Where lambda is the operating wavelength of the antenna, and theta is the maximum scanning angle;

[0016] The maximum element spacing that satisfies the antenna's scanning capability is obtained.

[0017] Further, step 102 includes:

[0018] The delay components and TR components of the antenna are designed symmetrically, with each delay component symmetrically distributed in both the azimuth and range directions with the previous delay component as the center point.

[0019] Further, step 103 includes:

[0020] Based on the antenna's scanning capability, the median delay required for the antenna's maximum scanning is calculated. During the beam control code calculation, the median delay of each delay component is added to the beam control code calculation, thus obtaining a beam control design that ensures stable delay. This ensures that the median delay of the delay components remains constant regardless of how the antenna scans during operation, thereby maintaining the antenna's delay stability.

[0021] Furthermore, step 103 also includes: according to different radar operating modes, during the antenna's wave control code calculation process, selecting the median of different delay amounts to participate in the calculation, so that the antenna has optimal performance in different radar operating modes.

[0022] Beneficial effects:

[0023] This invention effectively solves the problem of system delay jumps caused by electronic scanning of phased array antennas during radar system operation. This invention enables a complete design process to resolve the system delay jump problem during electronic scanning of phased array antennas. Attached Figure Description

[0024] Figure 1 This is a flowchart of a method for maintaining the delay stability of an active phased array antenna according to the present invention;

[0025] Figure 2 This is a schematic diagram of the phased array antenna topology of the present invention;

[0026] Figure 3 This is a schematic diagram of the antenna delay distribution without the present invention.

[0027] Figure 4 This is a schematic diagram of the antenna delay distribution using the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0029] This invention includes both hardware and software design. The hardware design primarily involves the topological structure design of the phased array antenna, enabling hardware implementation that supports delay reference adjustment. The software design mainly focuses on the antenna beam control algorithm, primarily used to adjust the delay reference based on different operating modes. This allows for antenna delay design tailored to varying operational needs, ensuring no system delay jumps occur during antenna scanning.

[0030] like Figure 1 As shown, a method for maintaining delay stability of an active phased array antenna according to the present invention includes the following steps:

[0031] Step 101: Estimate antenna parameters based on the antenna's technical specifications:

[0032] Specifically, the antenna aperture, element spacing, number of channels, and power in the azimuth and range directions of the phased array antenna are estimated based on the antenna's operating frequency, radiated power, beamwidth, scanning capability, and other indicators.

[0033] The azimuth and range spacing d of the antenna is determined by its scanning capability.

[0034]

[0035] Where lambda is the operating wavelength of the antenna, and theta is the maximum scanning angle. This allows us to obtain the maximum spacing that satisfies the scanning capability. By appropriately increasing the number of channels to an even number of elements, we can facilitate subsequent symmetrical structure design while ensuring scanning capability.

[0036] Step 102: Design the antenna topology:

[0037] Specifically, when designing the antenna topology, the delay components at each stage should be arranged symmetrically, ensuring that each stage of delay components presents a balance-like symmetrical distribution with the previous stage's delay as the center point in both the azimuth and range directions. This ensures that each stage of delay components maintains this topological layout. Furthermore, based on the designed antenna topology, the parameters of each stage of delay components, such as the maximum delay amount and minimum delay step, should be selected. This ensures that the subsequent antenna algorithm design is simple and easy to implement.

[0038] Generally, the maximum delay is related to the spacing between delay channels and the antenna scanning capability, while the minimum delay step is related to the delay distribution of each stage of the antenna and the antenna's operating bandwidth. The wider the antenna's operating bandwidth, the smaller the minimum delay step required. This effectively avoids the impact of dispersion problems caused by increased bandwidth on system performance.

[0039] Step 103: Design the beam control algorithm:

[0040] Specifically, compared to conventional beam control algorithms, the key to maintaining stable beam control lies in the calculation and allocation of delay amounts at different levels. First, the maximum scanning angle required for antenna operation is obtained based on the radar's operating mode. Then, the maximum delay amount of different level delay components is obtained based on the antenna's maximum scanning angle. Generally, the maximum delay amount of the first-level delay component is much larger than that of the second-level delay component. The quantized achievable delay amount closest to half of the maximum delay amount of each level delay component is used as the delay benchmark for beam control calculations. Thus, during electronic scanning of the antenna, the delay gradient of different levels of delay components will vary depending on the scanning angle, but the median of the delay amounts of different levels of delay components remains a fixed value (i.e., the delay benchmark for different levels of delay components), and the mean of the delay amounts of all delay components is also fixed. This ensures that the system delay is stable during electronic scanning of the antenna.

[0041] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

[0042] Example 1

[0043] This embodiment uses a one-dimensional linear array with two-stage delay components to specifically illustrate the method for maintaining delay stability. For example... Figure 2 As shown, a one-dimensional phased array antenna has 64 antenna elements with an element spacing of d = 15 mm. The antenna operates at a frequency of 10 GHz and has a scanning capability of ±30 degrees. A corresponding delay-stable wave control design implementation method is given, thereby verifying the effectiveness of the present invention.

[0044] The maximum delay required for the maximum antenna scanning angle can be obtained from the antenna scanning capability and antenna size.

[0045] The total length of the antenna is: L = 15 * 64 = 960 mm

[0046] The operating wavelength of the antenna is: lambda = 300 / 10 = 30mm

[0047] The maximum delay of the antenna is: Delay_num = L*(sin30) / lambda = 16 wavelengths

[0048] The maximum delay for the first-order delay is: Delay1_num = 7 * (8 * d) * (sin30) / lambda = 14 wavelengths

[0049] The maximum delay for the second-order delay is: Delay2_num = 3 * (2 * d) * (sin30) / lambda = 1.5 wavelengths.

[0050] The primary delay component can be designed as a 4-bit delay component with a minimum delay step of 1 wavelength and a total delay line length of 15 wavelengths. The primary delay component is a 1-to-4 design, connecting to the secondary delay components.

[0051] The secondary delay component can be designed with 3 bits, a minimum delay step of 0.25 wavelengths, and a total delay line length of 1.75 wavelengths. The secondary delay component is a 1-to-2 design, connecting to the TR component.

[0052] In the conventional antenna beam control calculation process, such as Figure 3 As shown, the initial antenna element is located at the origin, with a delay of 0. Other antenna elements are arranged sequentially, with coordinates d, 2*d, 3*d, ..., 63*d, corresponding to delays of d*sin(a), 2*d*sin(a), 3*d*sin(a), ..., 63*d*sin(a). The delay difference between elements is d*sin(a), where a is the antenna scanning angle. Therefore, in this example, the delay of the nth element is (n-1)*d*sin(a), and the average delay of all elements is 31.5*d*sin(a). When the scanning angle a changes, the average delay of all elements in the array changes with the scanning angle; the larger the scanning angle, the larger the average delay. This results in the entire radar system's delay continuously changing with the scanning angle during angular scanning.

[0053] The method proposed in this invention calculates the delay of each delay component in the array antenna by arranging the coordinates of each element sequentially from the center as the origin to both sides. For the 64-element antenna in this embodiment, the coordinates are -63*d / 2, -61*d / 2, ..., -d / 2, d / 2, ..., 61*d / 2, 63*d / 2. The corresponding delay values ​​are -63*d / 2*sin(a), -61*d / 2*sin(a), ..., -d / 2*sin(a), d / 2*sin(a), ..., 61*d / 2*sin(a), 63*d / 2*sin(a).

[0054] The primary delay component is designed with a delay of 15 wavelengths, and the secondary delay component is designed with a delay of 1.75 wavelengths. The maximum delay required for the primary delay to reach the maximum scanning angle is 14 wavelengths, and the maximum delay required for the secondary delay to reach the maximum scanning angle is 1.5 wavelengths. Since the final achievable delay of the delay components cannot be negative, the maximum delay required for single-sided scanning is (14 + 1.5) / 2 = 7.75 wavelengths. Therefore, the delay reference for the primary delay component is selected as 8 wavelengths, and the delay reference for the secondary delay component is selected as 1.5 / 2 = 0.75 wavelengths, for a total delay reference of 8.75 wavelengths. With this delay reference selected, a stable delay wave control design can be achieved.

[0055] like Figure 4 As shown, the calculated delay amounts for each element are 8.75-31.5*b, 8.75-30.5*b, ..., 8.75-0.5*b, 8.75+0.5*b, ..., 8.75+30.5*b, 8.75+31.5*b, where b = d*sin(a). Thus, the delay distribution of the entire antenna element presents a balance-like distribution, and the average delay of all elements in the entire antenna remains at 8.75 wavelengths, which will not change with the scanning angle α, thereby achieving the goal of maintaining system delay stability.

[0056] The above description is merely a general explanatory embodiment of the present invention and is not intended to limit the scope of protection of the present invention. The present invention can be applied to one-dimensional and two-dimensional array antenna systems.

[0057] Those skilled in the art will readily understand that the above description is merely 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 should be included within the scope of protection of the present invention.

Claims

1. A method of maintaining time delay stability of an active phased array antenna, characterized by, The method comprises the following steps: Step 101: estimating the antenna parameters according to the technical index requirements of the antenna; Step 102: designing the topology structure of the antenna; Step 103: designing the beam control algorithm to realize the delay stability of the phased array antenna, comprising: According to the scanning ability of the antenna, the median of the delay amount required by the antenna in the maximum scanning is calculated, and the median of the delay amount corresponding to each level of delay component is added to the beam control code calculation, so as to obtain the delay stable beam control design, so that the median of the delay amount of the delay component of the antenna is fixed during the working process, so as to maintain the delay stability of the antenna.

2. The method of claim 1, wherein the active phased array antenna is a 5 phased array antenna of a satellite. The step 101 comprises: The technical index requirements of the antenna include working frequency, radiation power, beam width and scanning ability, and the antenna parameters include the antenna aperture, unit spacing, channel number and power of the phased array antenna in the azimuth direction and the range direction; The unit spacing d of the antenna in the azimuth direction and the range direction is determined by the scanning ability of the antenna: ； Wherein, lambda is the working wavelength of the antenna, and theta is the maximum scanning angle; The maximum unit spacing satisfying the scanning ability of the antenna is obtained.

3. The method of claim 2, wherein the active phased array antenna is a 5 phased array antenna of a satellite. The step 102 comprises: The delay components and TR components of the antenna are symmetrically designed, and each level of delay component is symmetrically distributed around the center point of the previous level of delay component in the azimuth direction and the range direction.

4. The method of claim 1, wherein the active phased array antenna is a radar antenna. The step 103 further comprises: according to different working modes of the radar, different medians of the delay amount are selected to participate in the calculation during the antenna beam control code calculation, so that the antenna has the optimal performance in different working modes of the radar.

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