Asymmetric configuration and unbalanced feed spindle-shaped phase array antenna

Abstract

The invention discloses an asymmetrical configuration and unbalanced feed spindle-shaped phase array antenna, the appearance of an array element of the phase array antenna is a spindle body, the array element is gradually opened from top to bottom, and four feed pins extend from the array element to the lowermost end; in the feed mode of the array elements, the array elements use an unbalanced differential feed mode, a common base plate is introduced between adjacent pins of every two adjacent array elements to serve as a negative electrode, and feed control over one radiation unit is achieved through two ports. The spindle-shaped array element disclosed by the invention is gradually opened from top to bottom, is similar to a bullet or a leaf in shape, is of a quasi-self-similar configuration, and has a relatively wide working bandwidth and an attractive and neat appearance; by introducing the double number of feed pins, unbalanced feed becomes possible. Therefore, weighting factors of which the number is doubled can be provided for each array element, more complex and special directional diagrams can be synthesized, and special requirements of some occasions on the directional diagrams are met.

Description

Technical Field

[0001] The present invention relates to the technical field of phased array antennas, and in particular to a spindle-shaped phased array antenna with an asymmetric configuration and an unbalanced feed. Background Art

[0002] A phased array antenna uses a large number of closely arranged feed units to instantaneously form multiple overlapping far-field beams, thereby providing a larger observation field of view, observation sensitivity, and observation efficiency for relevant application scenarios. Compared with traditional single-beam and multi-beam antennas, a phased array antenna can provide a more uniform and continuous detection field of view. At the same time, since beam synthesis is achieved at the digital end, phased array antenna technology also has technical advantages in improving the signal-to-noise ratio of the receiving system, enhancing beam efficiency, correcting the accuracy of reflector antennas, and avoiding interference signals.

[0003] For existing phased array antennas, a symmetric (axisymmetric or symmetric with respect to the X-axis and Y-axis) antenna configuration is usually selected as the basic unit of the array, usually called an "element", and then the final phased array antenna array is formed by periodically replicating and moving the elements on the two-dimensional plane formed by the X-axis and Y-axis. By assigning a set of specific amplitude values and phase values to each element for feeding (i.e., the number of amplitude weighting factors = the number of elements and the number of phase weighting factors = the number of elements), the beam synthesis function is achieved. This design concept is very mature, but it still appears to be inadequate in application scenarios with high requirements for the shape and deflection angle of the synthesized beam.

[0004] Such special requirements for the synthesized beam are mainly reflected in the following aspects: the synthesized beam is not rotationally symmetric along the line-of-sight direction, but presents an approximately elliptical beam; or, it is required that the beam shapes synthesized in two polarization directions are different; or, it is required that the pointing direction of the synthesized beam deviates from the normal direction of the array by a large angle.

[0005] Therefore, in some occasions with high requirements for the synthesized beam (such as radio astronomy, radar observation, etc.), it is urgent to develop more structural parameters and more flexible beam synthesis mechanisms for phased array antennas, so that the synthesized beam meets the specific requirements of users, in order to improve the performance and practicality of phased array antennas.

[0006] The information disclosed in this background art section is only intended to deepen the understanding of the overall background art of the present invention, and should not be regarded as an admission or any form of implication that this information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of the present invention is to provide a spindle-shaped phased array antenna with an asymmetric configuration and an unbalanced feed to solve the problems existing in the prior art.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] The present invention provides a spindle-shaped phased array antenna with an asymmetric configuration and unbalanced feeding. The elements of the phased array antenna are spindle-shaped in appearance, gradually expanding from top to bottom, and extending four feeding pins at the bottom end. In terms of the feeding method of the elements, the elements use an unbalanced differential feeding form, and a common bottom plate is introduced as the negative electrode between the adjacent pins of every two adjacent elements, so as to realize the feeding control of a radiation unit by two ports.

[0010] Furthermore, the outer envelope of the spindle of the element uses an exponential function, and the outer contours in the XZ plane and the XY plane are not the same, presenting a non-rotationally symmetric configuration;

[0011] Let the contour functions be x = f1(z) and y = f2(z) respectively, with the Z-axis coordinate z as the independent variable, then the function expressions are:

[0012]

[0013] Among them, LN1 / LN2 is the linear decreasing degree of the envelope function, L is the longitudinal length of the element on the Z-axis, and there is only one length for the element, so the L values of the two envelope functions are the same; R1 / R2 is the opening rate of the exponential function, r a1 / r a2 is the maximum lateral extension of the two envelopes on the X / Y axis respectively, r t1 / r t2 is the spacing between the adjacent pins of every two adjacent elements, r t1 is the X-direction spacing, r t2 is the Y-direction spacing; when each of the above parameters of the two envelopes is the same, that is, LN1 = LN2 and R1 = R2 and r a1 = r a2 and r t1 = r t2 at this time, the element is a traditional symmetric element.

[0014] Adopting the above technical solutions, the present invention has the following beneficial effects:

[0015] 1. A more beautiful and tidy element configuration: The spindle-shaped element involved in the present invention gradually expands from top to bottom, similar to the shape of a bullet head or a leaf, which is a quasi-self-similar configuration, having a relatively wide working bandwidth and a beautiful and tidy appearance, and the working bandwidth can reach more than 3:1;

[0016] 2. More flexible element modeling mechanism: By introducing different envelope functions for the two polarization directions of the element, different radiation structures can be designed for the two polarization directions, so that different synthetic beams can be formed in the two polarization directions to meet the special requirements of corresponding scenarios;

[0017] 3. More flexible beam synthesis mechanism: By introducing a double number of feeding pins, unbalanced feeding becomes possible. Thus, a double number of weighting factors (i.e., a total of four groups of weighting matrices) can be provided for each element, which helps to synthesize more complex and special radiation patterns to meet the special requirements of radiation patterns in some occasions. Description of the Drawings

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 It is a three-dimensional model diagram of the asymmetric spindle-shaped element of the spindle-shaped phased array antenna with asymmetric configuration and unbalanced feeding of the present invention;

[0020] Figure 2 It is a schematic diagram of the outer envelope of the asymmetric spindle-shaped element of the spindle-shaped phased array antenna with asymmetric configuration and unbalanced feeding of the present invention on the XZ / XY plane;

[0021] Figure 3 It is a schematic diagram of the feeding method of the asymmetric spindle-shaped element of the spindle-shaped phased array antenna with asymmetric configuration and unbalanced feeding of the present invention;

[0022] Figure 4 It is a three-dimensional model diagram of the 5X6 array formed by the asymmetric spindle-shaped elements of the spindle-shaped phased array antenna with asymmetric configuration and unbalanced feeding of the present invention;

[0023] Figure 5 For Figure 4 top view;

[0024] Figure 6 It is a schematic diagram of the element numbers and port numbers of the 5X6 array formed by the asymmetric spindle-shaped elements of the spindle-shaped phased array antenna with asymmetric configuration and unbalanced feeding of the present invention;

[0025] Figure 7 It is a pseudo-color diagram schematic of the amplitude weighting matrix of the 5X6 array formed by the asymmetric spindle-shaped elements of the spindle-shaped phased array antenna with asymmetric configuration and unbalanced feeding of the present invention;

[0026] Figure 8 Schematic diagram of the pseudo-color map of the phase weighting matrix of the asymmetric spindle-shaped array elements of the spindle-shaped phased array antenna with asymmetric configuration and unbalanced feeding according to the present invention, forming a 5X6 array;

[0027] Figure 9 Schematic diagram of the synthesized beam formed under the excitation of the four groups of weighting matrices Mam-1, Mam-2, Mph-1, and Mph-2 according to the present invention;

[0028] Figure 10 In the second embodiment of the present invention, an elliptical illumination beam is obtained by optimizing 60 weighting factors. The left side is the 3D pattern, and the right side is the 2D pattern;

[0029] Figure 11 Schematic diagram showing that the two groups of amplitude weighting matrices and phase weighting matrices in the second embodiment of the present invention exhibit the characteristics of "unbalanced" feeding;

[0030] Figure 12 In the third embodiment of the present invention, a high-gain defocused beam is obtained by optimizing 60 weighting factors. The left side is the 3D pattern, and the right side is the 2D pattern;

[0031] Figure 13 Schematic diagram showing that the two groups of amplitude weighting matrices and phase weighting matrices in the third embodiment of the present invention exhibit the characteristics of "unbalanced" feeding. Detailed implementation manners

[0032] Next, the technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] The following will describe in detail the specific implementation manners of the present invention with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0034] Combined with Figures 1 - 3 As shown, the present invention provides a spindle-shaped phased array antenna with an asymmetric configuration and unbalanced feeding. The appearance of the array elements of the phased array antenna is spindle-shaped, gradually expanding from top to bottom, and extending four feeding pins at the bottom end; in terms of the feeding method of the array elements, the array elements use an unbalanced differential feeding form, and a common bottom plate is introduced as the negative electrode between the adjacent pins of every two adjacent array elements, so as to realize the feeding control of a radiation unit by two ports.

[0035] The outer envelope of the spindle of the array element in this application uses an exponential function, and its outer contour on the XZ plane is different from that on the XY plane, presenting a non-rotationally symmetric configuration;

[0036] Let its contour functions be x = f1(z) and y = f2(z) respectively, with the Z-axis coordinate z as the independent variable, then the function expressions are:

[0037]

[0038] Among them, LN1 / LN2 is the linear decreasing degree of the envelope function, L is the longitudinal length of the array element on the Z-axis, and there is only one length for the array element, so the L values of the two envelope functions are the same; R1 / R2 is the opening rate of the exponential function, r a1 / r a2 is the maximum lateral extension of the two envelopes on the X / Y axis respectively, r t1 / r t2 is the pitch between adjacent pins of every two adjacent array elements, r t1 is the X-direction pitch, r t2 is the Y-direction pitch; when each of the above parameters of the two envelopes is the same, that is, LN1 = LN2 and R1 = R2 and r a1 = r a2 and r t1 = r t2 at this time, the array element is a traditional symmetric array element.

[0039] Example 1:

[0040] As shown in combination with Figures 4 - 6 , for the phased array antenna formed by periodically replicating M = 5 and N = 6 on the X-axis and Y-axis respectively using this asymmetric spindle-shaped array element, it can be seen that since each array element presents an asymmetric configuration in the X-direction and Y-direction, the distribution of the 5X6 array in the X-direction and Y-direction also shows the rule of "unequal step lengths".

[0041] For a traditional phased array antenna, since there is only one feeding port for each array element, there are two weighting matrices corresponding to the amplitude weighting factor and the phase weighting factor, which can be named Mam and Mph. For the phased array antenna involved in this case, due to the use of an unbalanced feeding mode, each array element will "split" into an additional set of excitation ports, which are respectively named the "-1 port group" and the "-2 port group" for distinction. This relationship is shown in Figure 6 . Under the new design concept, for a phased array antenna with a scale of 5X6, the number of array elements is 30, and the number of ports is increased to 60. The weighting matrices are also increased from the traditional two groups of Mam and Mph to a total of four groups: Mam-1, Mam-2, Mph-1, and Mph-2.

[0042] Figure 7 andFigure 8 Shown is Figure 4 a pseudo-color map schematic of the amplitude weighting matrix and the phase weighting matrix for a 5X6 case. In this example, Mam-1 and Mam-2 have an equal amplitude relationship, while Mph-1 and Mph-2 have an anti-correlation relationship of 180°. This relationship is the differential feeding relationship in the general sense. The synthesized far-field beam is as shown in Figure 9 shown, which is a directional and broad far-field pattern, suitable for illumination and other applications of front-feed reflector antennas.

[0043] Since the number of weighting factors doubles, a more flexible beam synthesis mechanism can be obtained with double the RF link and digital end resources to meet the special requirements of the beam in related scenarios.

[0044] Embodiment 2:

[0045] This embodiment shows a design example according to the present invention, including its design process and optimized performance results. In an offset reflector system, it is often required that the illumination beam of the feed be elliptical, that is, the far-field pattern of the feed is non-axisymmetric around its pointing axis, and the beam width of the major axis is greater than that of the minor axis.

[0046] Therefore, still based on the aforementioned 5X6 Rocket phased array antenna, by optimizing its double number of weighting factors (a total of 60), an attempt is made to obtain an elliptical illumination beam. After nearly 3000 optimization iterations, the best optimization result is as shown in Figure 10 shown.

[0047] From Figure 10 the results, it can be seen that an elliptical illumination beam has been successfully synthesized in this case. By observing the 2D patterns of the E-plane and H-plane of the illumination beam, it can be seen that the synthesized beam is significantly elliptical in shape, with a maximum gain of 10.2 dBi, meeting the requirements of most reflectors for the feed gain. The difference in the 10 dB beam widths of the pattern on the major axis and the minor axis reaches 40.01°, which can very well meet the requirements of the offset reflector for the shape of the illumination beam.

[0048] The weighting factors corresponding to this optimal result are as shown in Figure 11As shown in a) and b). It can be seen from this set of pseudocolor diagrams that for the two amplitude weighting matrices Mam-1 and Mam-2, both show the global law of "strong in the middle and weak at the periphery" in terms of numerical distribution, but obvious differences have emerged in the specific values. The peripheral weighting coefficient of Mam-2 is significantly higher than that of Mam-1, with a difference of about 10%. The angular values of the phase weighting matrices Mph-1 and Mph-2 are neither equal nor strictly anti-correlated at 180°, but take free values respectively, showing a "non-equilibrium" feeding characteristic. This case fully demonstrates the advantages of non-equilibrium feeding, which doubles the amplitude and phase weighting factors of the phased array antenna, thus enabling better control of the beam shape and meeting the technical requirements of phased array antennas in special occasions.

[0049] Embodiment 3:

[0050] This embodiment shows another design example according to the present invention, including its design process and optimized performance results. In some phased array antennas or reflector systems, due to the need to expand the field of view or for electronic scanning, it is often required that the synthesized beam of the phased array antenna has a certain offset angle, that is, the direction of the synthesized beam is offset by a certain angle from the normal direction of the phased array antenna. In this offset situation, it is often difficult to simultaneously achieve a large offset angle and a high antenna gain.

[0051] Therefore, still based on the aforementioned 5X6 Rocket phased array antenna, the non-equilibrium feeding technology of this patent is adopted to optimize a double number of weighting factors (a total of 60) in an attempt to obtain a synthesized beam with an offset of 30°. After nearly 6000 optimization iterations, the best optimization result is as Figure 12 shown.

[0052] From Figure 12 the results, it can be seen that in this case, a large-angle offset beam is successfully synthesized. From the E-plane 2D pattern of the synthesized beam, it can be seen that the synthesized beam shows an obvious offset, its maximum gain is 17 dBi, the grating lobe suppression is below -12 dB, and the offset angle of the maximum gain is 30°, which can very well meet the technical requirements of some RF systems for beam offset.

[0053] The weighting factors corresponding to this optimal result are as Figure 13As shown in a) and b), it can be seen that for the two groups of amplitude weighting matrices Mam-1 and Mam-2, the numerical distribution pattern is no longer the trend of "strong in the middle and weak at the periphery", and the maximum value has also shifted. The distribution patterns of the two weighting matrices are similar, but there are obvious differences in specific numerical values. The peripheral weighting coefficients of Mam-2 are significantly higher than those of Mam-1, with a difference of about 20%. The angular values of the phase weighting matrices Mph-1 and Mph-2 are neither equal nor strictly anti-correlated at 180°, but each takes a free value, showing an "unbalanced" feeding characteristic. This case fully demonstrates the advantages of unbalanced feeding, which doubles the amplitude and phase weighting factors of the phased array antenna, enabling better control of the beam shape and the angle of maximum gain, and meeting the technical requirements for offset composite beams in special occasions.

[0054] In summary, compared with the prior art, the innovation points of the present invention are as follows:

[0055] 1. Asymmetric spindle-shaped element configuration: This is the key technical point of this patent. By constructing exponential functions with different parameters on two cutting planes as its outer contour, an asymmetric spindle-shaped element is modeled. The two contours only share the same longitudinal length L and are finely controlled by different four-item parameters, creating differences in aspects such as the linear decreasing degree, contour opening rate, lateral extension amount, and pin pitch, thereby creating different radiation structures for the two polarization directions and improving the flexibility of beam synthesis.

[0056] 2. Unbalanced feeding mechanism: This is the key technical point of this patent. Since each element extends four pins at the lower end and the number of polarizations is generally only 2, each element can be fed and excited in an unbalanced manner by two ports, which correspondingly leads to a total of four groups of weighting matrices, namely Mam-1, Mam-2, Mph-1, and Mph-2. The number of matrices and the number of weighting factors have both doubled. Therefore, with double the radio frequency link and digital end resources, the beam quality can be further improved and a more flexible beam synthesis mechanism can be created to meet the special requirements for the composite beam of the phased array antenna in related scenarios.

[0057] Finally, it should be noted that: The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spindle-shaped phased array antenna with an asymmetric configuration and unbalanced feeding, characterized in that: The array element of the phased array antenna is spindle-shaped in appearance, gradually opening from top to bottom, and extending four feeding pins at the bottom; in terms of the array element feeding method, the array element uses an unbalanced differential feeding form, and a common bottom plate is introduced as a negative electrode between adjacent pins of each pair of adjacent array elements, so that the feeding control of a radiating unit is realized by two ports.

2. The spindle-shaped phased array antenna with asymmetric configuration and unbalanced feeding according to claim 1, characterized in that: The outer envelope of the spindle of the array element uses an exponential function, and the outer contour on the XZ plane is different from that on the XY plane, presenting a non-rotationally symmetric configuration; Let the contour functions be x=f1(z) and y=f2(z), and the Z-axis coordinate z be the independent variable, then the function expression is: Among them, LN1 / LN2 is the linear decrease degree of the envelope function, L is the longitudinal length of the array element on the Z axis, and the array element can only have one length, so the L value of the two envelope functions is the same; R1 / R2 is the opening rate of the exponential function, r a1 / r a2 is the maximum lateral extension of the two envelopes on the X / Y axis, r t1 / r t2 Then, r is the distance between adjacent pins of every two adjacent array elements. t1 is the X-direction spacing, r t2 is the Y-direction spacing; when each of the above parameters of the two envelopes is the same, that is, LN1 = LN2 and R1 = R2 and r a1 =r a2 And r t1 =r t2 When , the array element is a traditional symmetrical array element.

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