A microstrip circularly polarized array antenna

Abstract

This application discloses a microstrip circularly polarized array antenna, comprising a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, and a third metal layer stacked from top to bottom; wherein the first metal layer comprises multiple radiating sub-elements arranged in an array, and the third metal layer has multiple feed lines; the first and second dielectric layers have metallized vias, through which the first and third metal layers are electrically connected; in the array of radiating sub-elements, adjacent radiating sub-elements are rotated relative to each other by an angle. The microstrip circularly polarized array antenna of this invention solves the technical problems of high high-frequency loss, poor performance, and narrow bandwidth in existing array antennas.

Description

Technical Field

[0001] This application relates to antenna technology, and more specifically, to a microstrip circularly polarized array antenna. Background Technology

[0002] Antennas are one of the most important passive front-end components in communication equipment. They play a crucial role in the performance of communication products. Array antennas basically consist of two main parts: a feed network and an array of antenna elements. Generally, it is required that the signals output from the feed network to each antenna element have equal amplitude and phase, low feed loss, a spacing of half the operating wavelength between two antenna elements, and high radiation efficiency.

[0003] Current array antenna feeding networks generally employ microstrip, waveguide, and substrate integrated waveguide methods. Microstrip feeding networks easily achieve equal amplitude and phase requirements through parallel feeding structure design, but microstrip lines suffer from high high-frequency loss and poor performance. Waveguides have the lowest transmission loss, but due to their large size, they are generally limited to serial feeding, satisfying equal amplitude and phase requirements only within a narrow frequency band. Parallel feeding, however, is constrained by waveguide width, making it difficult to meet the requirement of half the operating wavelength for antenna element spacing. Substrate integrated waveguides have low loss and are easier to fabricate and integrate than waveguides, but they suffer from the same problem: width limitations prevent them from meeting the requirement of half the operating wavelength for antenna element spacing. Therefore, existing array antenna technologies suffer from high high-frequency loss, poor performance, and narrow bandwidth. Utility Model Content

[0004] This invention addresses the technical problems of high high-frequency loss, poor performance, and narrow bandwidth in existing antenna technology. It provides a microstrip circularly polarized array antenna to overcome these shortcomings.

[0005] The solution to the above problems provided by this utility model is as follows:

[0006] A microstrip circularly polarized array antenna is provided, comprising a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, and a third metal layer stacked from top to bottom; wherein the first metal layer comprises multiple radiating sub-elements arranged in an array, and the third metal layer has multiple feed lines. Metallized vias are provided in the first and second dielectric layers, and the first and third metal layers are electrically connected through these metallized vias; in the array of radiating sub-elements, adjacent radiating sub-elements are rotated relative to each other by an angle.

[0007] Preferably, the multiple radiating sub-units arranged in the array are an N×N array, where N is a natural number.

[0008] Preferably, the array of multiple radiating sub-units is a 2×2 array, with adjacent radiating sub-units rotated 90° relative to each other.

[0009] Preferably, the radiating element is a circular metal sheet, and a set of micro-perturbation blocks extends symmetrically from the edge of the circular metal sheet. The line connecting the micro-perturbation blocks passes through the center of the circular metal sheet, and a feed point is set on the line offset from the micro-perturbation blocks.

[0010] Preferably, the diameter of the radiating element is half the operating wavelength of the antenna.

[0011] Preferably, the spacing between adjacent radiating sub-elements is half the operating wavelength of the antenna.

[0012] Preferably, the thickness of the first dielectric layer is 0.20–0.30 mm, and the thickness of the second dielectric layer is 0.40–0.60 mm.

[0013] Preferably, multiple feed lines on the third metal layer form a microstrip power divider for 90-degree phase difference equal amplitude feeding.

[0014] Preferably, the difference in feed line length between adjacent radiating sub-units is one-quarter of a wavelength.

[0015] The microstrip circularly polarized array antenna implementing this invention solves the technical problems of high high-frequency loss, poor performance, and narrow bandwidth in existing array antennas. By using a parallel transmission architecture formed by multiple radiating arrays and a microstrip power divider, the antenna bandwidth is increased, providing a high-gain, broadband, compact planar millimeter-wave array antenna. Feeding and radiation are achieved through a parallel feeding method, ensuring that the broadband characteristics of the array antenna remain unchanged in large-array applications. The path from the feed port to each radiating array sub-element is consistent, thus maintaining the performance of the array antenna and resolving the contradiction between broadband operation and high gain requirements. Simultaneously, by employing a rotating configuration of the array elements, each element forms a 90-degree spatial phase difference, thereby synthesizing circularly polarized array radiation. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a side view of a circularly polarized microstrip antenna according to an embodiment of the present invention;

[0019] Figure 2 for Figure 1A schematic diagram of a set of array units in an embodiment;

[0020] Figure 3 for Figure 2 A schematic diagram of a single array unit in the embodiment;

[0021] Figure 4 This is a schematic diagram of a feeder wire according to an embodiment of the present invention;

[0022] Figure 5 This is a gain curve diagram of an embodiment of the present invention;

[0023] Figure 6 This is a voltage standing wave ratio (VSWR) characteristic diagram of an embodiment of the present invention. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0025] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] like Figure 1The image shows a side view of a preferred embodiment of the microstrip circularly polarized array antenna of this invention. In this embodiment, the microstrip circularly polarized array antenna has a layered structure, specifically including a first metal layer 10, a first dielectric layer 20, a second metal layer 30, a second dielectric layer 40, and a third metal layer 50 stacked from top to bottom. The first metal layer 10 consists of multiple radiating elements arranged in an array. These radiating elements can be constructed by covering the surface of the first dielectric layer 20 with a metal layer and then directly constructing the radiating elements through etching or other methods. The third metal layer 50 has multiple feed lines. Metallized vias are provided in the first dielectric layer 20 and the second dielectric layer 40, through which the first metal layer 10 and the third metal layer 50 are electrically connected. In the array of multiple radiating elements, adjacent radiating elements form a circularly polarized array radiation by relative rotation and changing the feed position.

[0027] Classification by antenna function Figure 1 The microstrip circularly polarized array antenna has a first dielectric layer 20 and a first metal layer 10 forming the radiating dielectric substrate, and a second metal layer 30, a second dielectric layer 40, and a third metal layer 50 forming the feeding dielectric substrate. The radiating dielectric substrate and the feeding dielectric substrate have different thicknesses and dielectric constants. Since the radiating dielectric substrate and the feeding dielectric substrate are independent dielectric substrates, the thickness and dielectric constant of the radiating dielectric substrate can be selected according to the design requirements of the array antenna's feeding and radiation. The thickness and dielectric constant of the feeding dielectric substrate can be selected according to the ease of integration with active circuits. This flexible selection helps ensure the bandwidth and gain of the array antenna. Generally, at a given center frequency, a substrate with a high dielectric constant can reduce the antenna size, but this will affect the bandwidth; while a substrate with a low dielectric constant and a larger thickness can achieve wide bandwidth and high gain. Given the center frequency and size requirements of the antenna, two substrates can be flexibly combined. In an optional embodiment, the thickness of the radiating dielectric substrate is 0.20 to 0.30 mm, and the thickness of the feeding dielectric substrate is 0.40 to 0.60 mm. For example, the thickness of the radiating dielectric substrate is 0.254 mm, and the thickness of the feeding dielectric substrate is 0.508 mm.

[0028] In preparation such as Figure 1The microstrip circularly polarized array antenna with the structure shown can be fabricated using standard multilayer circuit board processes, facilitating mass production and offering high reliability and high repeatability. Specifically, the first metal layer 10, the first dielectric layer 20, and the second metal layer 30 are a first substrate with metal cladding on both sides; the second metal layer 30, the second dielectric layer 40, and the third metal layer 50 are considered as a second substrate with metal cladding on both sides. The first and second substrates are stacked to form a structure consisting of the sequentially stacked first metal layer 10, first dielectric layer 20, second metal layer 30, second dielectric layer 40, and third metal layer 50. During the stacking process, the second metal layers of the first substrate overlap and are pressed together into a single layer. Preferably, all covering metal layers are copper.

[0029] like Figure 2 As shown Figure 1 A schematic diagram of a set of array units in an embodiment. Figure 3 This is a schematic diagram of a single radiating sub-unit. A 2×2 array includes a first radiating sub-unit 11, a second radiating sub-unit 12, a third radiating sub-unit 13, and a fourth radiating sub-unit 14, arranged in a square. Each radiating sub-unit has the same structure, with adjacent sub-units rotated 90 degrees relative to each other. Taking the fourth radiating sub-unit 14 as an example, its structure is as follows... Figure 3 As shown, the fourth radiating sub-element 14 is a circular metal patch structure, with a set of micro-perturbation blocks symmetrically extending from the edge of the circle. The line connecting these micro-perturbation blocks passes through the center of the circular metal patch structure, and a feed point is set off from this line. By setting the micro-perturbation blocks, circular polarization of a single radiating sub-element can be achieved. The impedance matching of the antenna can be adjusted by changing the position of the feed point. The four radiating elements are a planar patch array composed of microstrip lines, which can ensure efficient feeding and radiation while maintaining a planar structure. Rotating the fourth radiating sub-element 14 counterclockwise by 90° yields the first radiating sub-element 11; rotating it clockwise by 90° yields the third radiating element 13; and rotating it 180° yields the second radiating sub-element 12. Through the rotational configuration of the array elements, each element forms a 90-degree spatial phase difference, thereby synthesizing circularly polarized array radiation. Preferably, the diameter of each radiating sub-element is half the wavelength corresponding to the desired center frequency, and the spacing between adjacent radiating sub-element elements is half the wavelength corresponding to the desired center frequency.

[0030] In this embodiment, a 2×2 array is given as an example. In other embodiments, this invention can also exist as a subarray. Multiple subarrays can be N×N arrays, where N is a natural number.

[0031] use Figure 2The radiating sub-element consists of four elements fed in parallel. This ensures that the wideband characteristics of the array antenna remain unchanged when used in large array applications. Because of the parallel feeding, the path from the feed port to each radiating sub-element is consistent. Therefore, even if the signal frequency changes, the phase of the signal reaching each element remains consistent, thus maintaining the performance of the array antenna and resolving the contradiction between wideband operation and high gain requirements.

[0032] like Figure 4 The diagram shows a feed line according to an embodiment of the present invention. A feed network is provided on the third metal layer 50, and the feed network consists of multiple feed lines. In this embodiment, the feed network is located directly below the first metal layer 10, and by designing the feed line corresponding to each radiating sub-unit, the length difference of the feed line corresponding to adjacent radiating sub-units is made to be a quarter wavelength (λ), thereby causing a phase difference of 90° due to the difference in the battery wave transmission path. Specifically, one end of the first feeder wire 54, the second feeder wire 55, the third feeder wire 56, and the fourth feeder wire 57 are connected to the feed point on the corresponding radiating sub-unit through metallized vias. The first feeder wire 54 is a straight line with a length of L1. The second feeder wire 55 is directly connected to the first feeder wire 54, and it adds multiple right-angle bends to the straight line to form a rectangular wave-like structure with a total length of L1+λ / 4. The third feeder wire 56 is a straight line with a length of L2. The fourth feeder wire 57 is directly connected to the third feeder wire 56, and it adds multiple right-angle bends to the straight line to form a rectangular wave-like structure with a total length of L2+λ / 4. A fifth feeder wire 52 is further introduced, one end of which is connected to the connection point of the first feeder wire 54 and the second feeder wire 55, and the other end is connected to the sixth feeder wire 53 through a connecting line 51. The other end of the sixth feeder wire 53 is connected to the connection point of the third feeder wire 56 and the fourth feeder wire 57. The length difference between the fifth feed line 52 and the sixth feed line 53 is half a wavelength. By setting the feed line lengths as described above, the length difference between the feed lines of adjacent radiating sub-elements is one-quarter of a wavelength, achieving a 90-degree phase difference equal-amplitude feed network. Using this feed network structure, which is a microstrip power divider with a planar structure, results in a compact and small-sized array antenna.

[0033] When designing the various dimensions of the antenna in the above embodiments, it is necessary to first determine the center frequency. This center frequency refers to the frequency at which the antenna performs best. Deviating from this frequency, whether the frequency decreases or increases, the antenna performance will degrade. The principle is that the structure and size of the antenna's components, such as transmission lines, transmission line conversion structures, and radiating elements, are all related to the signal frequency. When designing an antenna, a center frequency must be set according to actual requirements. This center frequency serves as the design input for designing each component of the antenna. Then, when designing the antenna and its components, a scheme that minimizes performance degradation when deviating from the center frequency will be considered as much as possible. After determining the center frequency, the various parameters can be determined sequentially.

[0034] Using the above Figures 1-4 The gain curve and voltage standing wave ratio (VSWR) characteristic of the microstrip circularly polarized array antenna structure are shown in the figure below. Figure 5 and Figure 6 As shown. Figure 5 Measurements were taken at different θ angles when the azimuth angle φ = 90°. At 2.4 GHz, the main lobe amplitude was 12.8 dBi, and the θ width at a 3 dB amplitude was 53.1°. Figure 6 It can be seen that the antenna frequency is in the range of 2.35-2.45 GHz. From Figure 5 , 6 As can be seen from the curve, this embodiment solves the technical problems of high high-frequency loss, poor performance, and narrow bandwidth in existing array antennas. By using a parallel transmission architecture formed by multiple radiating arrays of subarrays and microstrip power dividers, the bandwidth of the antenna is increased, providing a high-gain, wideband, compact planar millimeter-wave array antenna.

[0035] Specific examples in this embodiment can be found in the examples described in the above embodiments and exemplary implementations, and will not be repeated here.

[0036] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A microstrip circularly polarized array antenna, characterized in that, It includes a first metal layer (10), a first dielectric layer (20), a second metal layer (30), a second dielectric layer (40), and a third metal layer (50) stacked from top to bottom; wherein the first metal layer (10) is a plurality of radiating sub-units arranged in an array, and the third metal layer (50) is provided with a plurality of feed lines; the first dielectric layer (20) and the second dielectric layer (40) are provided with metallized vias, and the first metal layer (10) and the third metal layer (50) are electrically connected through the metallized vias; in the array of radiating sub-units, adjacent radiating sub-units are rotated relative to each other by an angle.

2. The microstrip circularly polarized array antenna according to claim 1, characterized in that, The array consists of multiple radiating sub-units arranged in an N×N array, where N is a natural number.

3. The microstrip circularly polarized array antenna according to claim 2, characterized in that, The array consists of multiple radiating sub-units arranged in a 2×2 array, with adjacent radiating sub-units rotated 90° relative to each other.

4. The microstrip circularly polarized array antenna according to claim 3, characterized in that, The radiation array element is a circular metal sheet, with a set of micro-perturbation blocks symmetrically extending from the edge of the circular metal sheet. The lines connecting the micro-perturbation blocks pass through the center of the circular metal sheet, and feed points are set on the lines offset from the micro-perturbation blocks.

5. The microstrip circularly polarized array antenna according to claim 4, characterized in that, The diameter of the radiating sub-element is half the operating wavelength of the antenna.

6. The microstrip circularly polarized array antenna according to claim 4, characterized in that, The spacing between adjacent radiating sub-elements is half the operating wavelength of the antenna.

7. The microstrip circularly polarized array antenna according to claim 1, characterized in that, The thickness of the first dielectric layer is 0.20–0.30 mm, and the thickness of the second dielectric layer is 0.40–0.60 mm.

8. The microstrip circularly polarized array antenna according to claim 4, characterized in that, Multiple feed lines on the third metal layer form a microstrip power divider for equal-amplitude feeding with a 90-degree phase difference.

9. The microstrip circularly polarized array antenna according to claim 4, characterized in that, The feed line length difference between adjacent radiating sub-units is one-quarter of a wavelength.

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