Low sidelobe implementation method for unequal power division feed after flexible power combination and phased array radar

Abstract

The invention relates to an antenna and microwave technology, in particular to a low sidelobe implementation method for unequal power division feed after flexible power combination and a phased array radar. According to the method, on the premise that the determined transmitting power is kept, the power of a transmitting assembly is synthesized through a power divider, and then high side lobe suppression of a transmitting beam is achieved in an unequal power divider feeding mode. The transmitting power and the transmitting low side lobe performance of the weather radar are guaranteed, meanwhile, the variety of transmitting assemblies is unified, cost control is achieved, and the actual engineering application requirement of the radar in the meteorological field is met.

Description

Technical Field

[0001] This invention relates to antenna and microwave technology, specifically to a method for achieving low sidelobes with flexible combined power and unequal power feeding, and a phased array radar. Background Technology

[0002] Phased array radar has gradually become the main form of weather radar due to its rapid scanning characteristics. However, unlike radar in other fields, weather radar requires not only maintaining a certain transmission power during operation but also relatively high sidelobe suppression. At the same time, it is also necessary to effectively reduce the cost of the radar while maintaining high performance.

[0003] Based on the above requirements, phased array weather radars generally use row feed arrays. In the azimuth direction, a fixed amplitude weighting is used to achieve low sidelobes. In this case, the radiated power of each row feed is determined by the feed power. In the elevation direction, power amplifiers are used to power each row feed. Thus, the transmit power and elevation sidelobe level of a phased array weather radar are determined by the elevation-direction feeding method.

[0004] In typical designs, transmitter components with power steps are fitted with Taylor weights to form Taylor step weights, aiming to achieve the lowest possible sidelobes. However, this design not only increases the number of transmitter component types but also limits the achievable low sidelobe level due to the step weights. This results in suboptimal cost and performance in engineering designs.

[0005] To further improve the performance of the phased array weather radar's transmitted beam and control its implementation cost, there is an urgent need for a low sidelobe implementation method with flexible power combining and unequal power feeding. Summary of the Invention

[0006] The purpose of this invention is to provide a method for achieving low sidelobes through flexible power combining and unequal power divider feeding. This method, while maintaining a fixed transmit power, achieves high sidelob suppression of the transmit beam by combining the transmit component power through a power divider and then feeding it through an unequal power divider. It ensures the transmit power and low sidelob performance of weather radar while also standardizing the types of transmit components, achieving cost control, and meeting the practical engineering application needs of radar in the meteorological field.

[0007] This invention provides a method for achieving low sidelobes with flexible combined power and unequal power split feeding, applied to a phased array radar. The phased array radar has M row feed elements. The method includes the following steps:

[0008] S1: Calculate the sidelobe suppression weighting coefficients for each feed unit; using Indicates the first Sidelobe suppression weighting coefficients for each feed unit;

[0009] S2: Calculate the total number of channels for the transmitting component:

[0010]

[0011] in, Indicates the total number of channels in the transmitting component;

[0012] Indicates the total transmission power;

[0013] This indicates the transmit power of a single channel of the transmitting component;

[0014] S3: Before calculation The accumulated value of the sidelobe suppression weighting coefficients of each row feed unit, and the total accumulated value of the sidelobe suppression weighting coefficients of the row feed unit:

[0015]

[0016]

[0017] in, Indicates the preceding The cumulative value of the sidelobe suppression weighting coefficients of each feed unit;

[0018] This represents the total accumulated value of the sidelobe suppression weighting coefficients of the line feed unit;

[0019] S4: Calculate the weighted equal score:

[0020]

[0021] in, Indicates weighted average scores;

[0022] S5: Based on the preset threshold Solve the following equation:

[0023]

[0024]

[0025] get Solution:

[0026]

[0027] in, Indicates the first There are solutions with a certain number of channels; and they satisfy...

[0028] Indicates and The corresponding number The number of solutions for each row feed unit;

[0029] S6: For the first row feed unit to the second row feed unit Each row feed unit, using The first transmission component channel, and the second The power ratio of each row feeder unit is:

[0030]

[0031] when At that time, for the first +1 row feed unit to the first Each row feed unit, using The first transmission component channel, and the second The power ratio of each row feeder unit is:

[0032]

[0033] For the The feed unit to the first The first row feed unit is connected to the first row feed unit to the second row feed unit. Each row feeder unit is mirror-symmetrical.

[0034] Preferably, the algorithms for calculating the sidelobe suppression weighting coefficients include the Chebyshev weighting algorithm, the polynomial weighting algorithm, or the Taylor power weighting algorithm.

[0035] The present invention also provides a phased array radar that uses the above-described method to achieve low sidelobes.

[0036] Beneficial effects:

[0037] 1. While ensuring transmission power, the phased array transmit beam sidelobe suppression was achieved by using combined transmit power and unequal power distribution feeding, thus ensuring high transmit power and low sidelobe of the array in a low-cost manner.

[0038] 2. This implementation method only requires adding an unequal power distribution feeder design, without changing the transmitting components. It is simple to implement and has low cost.

[0039] 3. The Taylor weighted fitting achieved by this method is better than that of the stepped Taylor weighted fitting, and can achieve lower sidelobes without wasting transmission power. Attached Figure Description

[0040] Figure 1 This is a power supply architecture diagram in an embodiment of the present invention;

[0041] Figure 2 The embodiments of this invention include unequal power distribution combinations and power ratios.

[0042] Figure 3This refers to the amplitude weighting value of each row feed unit in the embodiments of the present invention;

[0043] Figure 4 This is a beam pattern implemented in an embodiment of the present invention. Detailed Implementation

[0044] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0045] A method for achieving low sidelobes with flexible combined power and unequal power split feeding, applied to a phased array radar, wherein the phased array radar has M row feed elements, the method includes the following steps:

[0046] S1: Calculate the sidelobe suppression weighting coefficient for each row feed unit; using Indicates the first The sidelobe suppression weighting coefficients of each row feed unit; the algorithms for calculating the sidelobe suppression weighting coefficients include Chebyshev weighting algorithm, polynomial weighting algorithm, and Taylor power weighting algorithm; in this embodiment, Taylor power weighting algorithm is used to calculate the sidelobe suppression weighting coefficients;

[0047] In this embodiment, the power supply architecture is as follows: Figure 1 As shown, M=64; the design specifications require a transmit power of 1600W, a transmit sidelobe level of -23dB, and a beamwidth of less than 1.8°.

[0048] S2: Calculate the total number of channels for the transmitting component:

[0049]

[0050] in, Indicates the total number of channels in the transmitting component;

[0051] Indicates the total transmission power;

[0052] This indicates the transmit power of a single channel of the transmitting component;

[0053] In this embodiment, W, =40W, therefore the calculation yields =40;

[0054] S3: Before calculation The accumulated value of the sidelobe suppression weighting coefficients of each row feed unit, and the total accumulated value of the sidelobe suppression weighting coefficients of the row feed unit:

[0055]

[0056]

[0057] in, Indicates the preceding The cumulative value of the sidelobe suppression weighting coefficients of the line feed unit;

[0058] This represents the total accumulated value of the sidelobe suppression weighting coefficients of the line feed unit;

[0059] In this embodiment, the result is calculated according to the above formula. =28.65;

[0060] S4: Calculate the weighted equal score:

[0061]

[0062] in, Indicates weighted average scores;

[0063] In this embodiment, the result is calculated according to the above formula. =0.72;

[0064] S5: Based on the preset threshold Solve the following equation:

[0065]

[0066]

[0067] get Solution:

[0068]

[0069] in, Indicates the first There are solutions with a certain number of channels; and they satisfy...

[0070] Indicates and The corresponding number The number of solutions for each row feed unit;

[0071] In this embodiment The value of is 0.2; thus, 6 solutions to the above equation are obtained:

[0072]

[0073] Threshold This determines the accuracy of the Taylor-weighted fitting, but Setting the value too small may result in too many power channels being required, increasing the difficulty of implementation. Therefore, the value should be set as needed in the design.

[0074] S6: For the first row feed unit to the second row feed unit Each row feed unit, using The first transmission component channel, and the second The power ratio of each row feeder unit is:

[0075]

[0076] when At that time, for the first +1 row feed unit to the first Each row feed unit, using The first transmission component channel, and the second The power ratio of each row feeder unit is:

[0077]

[0078] For the The feed unit to the first The first row feed unit is connected to the first row feed unit to the second row feed unit. Each row feeder unit is mirror-symmetrical.

[0079] Further fine-tuning can be done based on the simulation results, which will not be elaborated here.

[0080] In this embodiment, the 1st to the 11th ( =11) row feed units, using 1 ( =1) transmission component channel, and the first The power ratio of each row feeder unit is:

[0081]

[0082] Specifically, the power ratios of the 1st to 11th row feed units are: 0.035: 0.038: 0.042: 0.049: 0.059: 0.072: 0.089: 0.111: 0.136: 0.167: 0.202;

[0083] 12th ( +1=12) to the 14th ( =14) row feed units, using 1 ( ) transmission component channel, and the first The power ratio of each row feeder unit is:

[0084]

[0085] Specifically, the power ratio of the 12th to 14th row feed units is: 0.280:0.332:0.388;

[0086] Similarly, the power ratio of the 15th to the 16th row feed unit is 0.466:0.534;

[0087] In the 17th ( +1=17) to the 26th ( =26) row feed units, using 9 ( =9) transmission component channels, and the first The power ratio of each row feeder unit is:

[0088]

[0089] Specifically, the power ratios of the 17th to 26th row feed units are: 0.064:0.072:0.080:0.088:0.097:0.105:0.113:0.120:0.128:0.133;

[0090] Similarly, the power ratios of the 27th to 32nd row feed units are: 0.156:0.161:0.166:0.170:0.173:0.174.

[0091] The 33rd to 64th row feed units are mirror images of the 1st to 32nd row feed units. The unequal power distribution combinations and power allocation in this embodiment are as follows: Figure 2 As shown.

[0092] The weighted sum of the feed amplitudes for each row based on the power ratio in this embodiment is as follows: Figure 3 As shown, it enables 64 line feeds to form a radiation pattern in the pitch direction, as shown in the figure. Figure 4 As shown. At this point, an ultra-low sidelobe of -33.35dB with a transmit power of 1600W (lossless) and a beamwidth of 1.79° were achieved, meeting the performance requirements.

[0093] It is understood that the line feed unit is just one commonly used unit form in weather radar. Any other unit form can be used here, which is also an equivalent implementation of the present invention.

[0094] The technical solution of this invention is based on the symmetrical sidelobe suppression requirement, so only half of the result is calculated, and the other half is obtained directly through mirror symmetry. If there is an asymmetrical sidelobe suppression requirement, all line feed units are calculated directly, which is also an equivalent implementation of this invention.

[0095] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for achieving low sidelobes with flexible combined power and unequal power split feeding, applied to a phased array radar, wherein the phased array radar has M row feed elements, characterized in that, The method includes the following steps: S1: Calculate the sidelobe suppression weighting coefficients for each feed unit; using Indicates the first Sidelobe suppression weighting coefficients for each feed unit; S2: Calculate the total number of channels for the transmitting component: in, Indicates the total number of channels in the transmitting component; Indicates the total transmission power; This indicates the transmit power of a single channel of the transmitting component; S3: Before calculation The accumulated value of the sidelobe suppression weighting coefficients of each row feed unit, and the total accumulated value of the sidelobe suppression weighting coefficients of the row feed unit: in, Indicates the preceding The cumulative value of the sidelobe suppression weighting coefficients of each feed unit; This represents the total accumulated value of the sidelobe suppression weighting coefficients of the line feed unit; S4: Calculate the weighted equal score: in, Indicates weighted average scores; S5: Based on the preset threshold Solve the following equation: get Solution: in, Indicates the first There are solutions with a certain number of channels; and they satisfy the following conditions: Indicates and The corresponding number The number of solutions for each row feed unit; S6: For the first row feed unit to the second row feed unit Each row feed unit, using The first transmission component channel, and the second The power ratio of each row feeder unit is: when At that time, for the first +1 line feed unit to the first Each row feed unit, using The first transmission component channel, and the second The power ratio of each row feeder unit is: For the The feed unit to the first The first row feed unit is connected to the first row feed unit to the second row feed unit. Each row feeder unit is mirror-symmetrical.

2. The method for achieving low sidelobe distribution of flexible combined power and unequal power distribution according to claim 1, characterized in that, Algorithms for calculating the sidelobe suppression weighting coefficients include the Chebyshev weighting algorithm, the polynomial weighting algorithm, or the Taylor power weighting algorithm.

3. A phased array radar, characterized in that, Low sidelobe is achieved using the method described in any one of claims 1 to 2.

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