Microstrip patch phased array antenna

Abstract

The invention discloses a microstrip patch phased-array antenna, and relates to the technical field of phased-array antennas, and the microstrip patch phased-array antenna comprises a plurality of microstrip patch antenna units which are arranged in a grid at equal intervals and a plurality of rectangular coupling branches. For a single microstrip patch antenna unit, the square radiation patch is located in the center of the upper surface of the first dielectric substrate, the coupling feed structure is located between the second dielectric substrate and the first dielectric substrate, and the two ends of the coupling feed structure are connected with the metal ground through the metal short circuit column and the metal feed column respectively for coupling feed. A rectangular coupling branch knot is arranged between every two antenna units, the distance between the branch knot and the two units is consistent, the branch knot and the square radiation patch are coplanar, and the long side of the branch knot is parallel to a connecting line of projection centers of the unit metal short circuit column and the feed column. According to the scheme, transverse coupling between antenna units can be enhanced, a multi-resonance mode can be excited, the problems that a microstrip patch phased array is narrow in bandwidth, unit mutual coupling is high during wide-angle scanning, impedance mismatching is serious, scanning blind areas are prone to occurring, and gain is reduced are effectively solved, and the antenna is suitable for scenes such as broadband radars.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of phased array antennas, in particular to a microstrip patch phased array antenna. BACKGROUND

[0002] As the core equipment for obtaining all-weather, all-time strategic and tactical information, the detection capability of radar directly depends on the performance of the front-end antenna system. As a key component of modern radar, the phased array antenna needs to have wide operating bandwidth and large angle scanning capability to support high-resolution detection and rapid spatial coverage requirements.

[0003] Microstrip patch antennas are widely used in phased array design due to their low profile and easy integration, but the inherent narrow bandwidth and poor wide-angle scanning performance are particularly prominent at the array level. When the scanning angle increases, the mutual coupling effect between units is enhanced, leading to serious impedance mismatch and easy occurrence of scanning blind area and gain reduction. Although the existing wide-angle scanning unit design (such as patent CN112290207A) can achieve ±60° scanning at 27-29 GHz, the bandwidth is only 7.1%, which is difficult to meet the application requirements of wideband radar. How to maintain wideband matching and achieve stable beam scanning in the array environment has become a key technical problem in the design of phased array antennas. SUMMARY

[0004] The purpose of the present application is to provide a microstrip patch phased array antenna that can achieve wideband matching and stable beam scanning, and has a simple structure, low profile and easy integration.

[0005] To achieve the above purpose, the present application provides the following solutions: A microstrip patch phased array antenna, comprising: a plurality of microstrip patch antenna units arranged in a grid at equal intervals, and a plurality of rectangular coupling branches.

[0006] For any microstrip patch antenna unit, the microstrip patch antenna unit comprises, from top to bottom, a square radiation patch, a first dielectric substrate, a coupling feed structure, a second dielectric substrate, a metal ground, a metal shorting post penetrating through the second dielectric substrate, and a metal feed post; the square radiation patch is located on the top surface of the center of the first dielectric substrate, the coupling feed structure is located between the second dielectric substrate and the first dielectric substrate, and the two ends of the coupling feed structure are connected to the metal ground through the metal shorting post and the metal feed post, respectively.

[0007] A rectangular coupling branch is provided between any two microstrip patch antenna units, the distance between the rectangular coupling branch and the two microstrip patch antenna units is consistent, and the rectangular coupling branch and the square radiation patch of each microstrip patch antenna unit are located in the same plane; the two long edges of the rectangular coupling branch are parallel to the connecting line of the projection centers of the metal shorting post and the metal feed post of any microstrip patch antenna unit on the top surface of the second dielectric substrate.

[0008] Optionally, the coupling feeding structure comprises a first microstrip feeding line, a second microstrip feeding line and a circular patch, the first microstrip feeding line is wider than the second microstrip feeding line, one end of the second microstrip feeding line is connected to one end of the first microstrip feeding line, the other end of the second microstrip feeding line is connected to the circular patch, the circular patch is located at the center lower surface of the first dielectric substrate, the circular patch is connected to the metal ground through a metal shorting post to form a short-circuit ground structure; the end of the first microstrip feeding line away from the second microstrip feeding line is connected to a feeding port opened in the metal ground through a metal feeding post to realize coaxial feeding excitation.

[0009] Optionally, the first microstrip feeding line and the second microstrip feeding line are both in rectangular structure.

[0010] Optionally, the part of the first microstrip feeding line not coinciding with the square radiation patch extends in the width direction with a plurality of feeding branches.

[0011] Optionally, the first dielectric substrate and the second dielectric substrate both adopt Rogers RT5880 material, the relative dielectric constant is 2.2, and the thicknesses are 2.286 mm and 0.254 mm respectively.

[0012] Optionally, the plurality of microstrip patch antenna units are arranged in N×M rectangular grid to form, extend along the X direction and the Y direction, and N and M are the numbers of the microstrip patch antenna units in the X direction and the Y direction respectively.

[0013] Optionally, the plurality of microstrip patch antenna units are arranged in N×N rectangular grid to form, extend along the X direction and the Y direction, and N is the number of the microstrip patch antenna units in the X direction and the Y direction.

[0014] Optionally, the center distance of two adjacent microstrip patch antenna units in the X direction is 13.2 mm, and the center distance of two adjacent microstrip patch antenna units in the Y direction is 12.3 mm.

[0015] According to the specific embodiments provided in the application, the following technical effects are disclosed: This application provides a microstrip patch phased array antenna. In this phased array antenna, several antenna elements are arranged in an equally spaced grid, which can ensure the uniformity of the array radiation field and provide a structural basis for subsequent stable beam scanning. For any microstrip patch antenna element, the layered design of two dielectric substrates can optimize the electromagnetic propagation characteristics of the antenna and reduce signal loss. The central layout of the square patch can ensure the symmetry of the radiation pattern, avoid beam distortion caused by patch offset, and improve the beam pointing accuracy during wide-angle scanning. The coupled feeding structure enhances electromagnetic coupling efficiency and widens the energy transmission bandwidth. At the same time, the insulation isolation between the upper and lower dielectric substrates reduces parasitic interference between the feeding structure and the radiating patch. The metal short-circuit post can excite additional resonant modes, effectively compensating for the inherent narrow bandwidth defect of microstrip patch antennas and widening the antenna's operating bandwidth. The metal feeding post realizes coaxial feeding excitation, ensuring the stability of signal transmission and alleviating the impedance mismatch problem caused by unstable feeding during wide-angle scanning. A rectangular coupling stub is provided between any two microstrip patch antenna elements, which enhances the electromagnetic coupling energy transmission capability between elements. Especially during large-angle scanning, it can compensate for the impedance mismatch in the end-fire direction caused by phase tilt, and significantly improve the stability of H-plane scanning. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, 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.

[0017] Figure 1 This is a schematic diagram of the structure of a microstrip patch phased array antenna provided in one embodiment of this application.

[0018] Figure 2 This is a schematic diagram of the structure of a microstrip patch antenna element in a microstrip patch phased array antenna according to an embodiment of this application.

[0019] Figure 3 This is a side view of a microstrip patch antenna element in a microstrip patch phased array antenna according to an embodiment of this application.

[0020] Figure 4 The active voltage standing wave ratio (VSWR) curves of a microstrip patch phased array antenna at different scanning angles in the E-plane are provided in another embodiment of this application.

[0021] Figure 5 The active voltage standing wave ratio (VSWR) curves of a microstrip patch phased array antenna at different scanning angles in the H-plane are provided in another embodiment of this application.

[0022] Figure 6A microstrip patch phased array antenna provided for another embodiment of the present application has an E-plane pattern at 10 GHz.

[0023] Figure 7 A microstrip patch phased array antenna provided for another embodiment of the present application has an H-plane pattern at 10 GHz.

[0024] Reference signs: 1: microstrip patch antenna unit; 1-1: square radiation patch; 1-2: first dielectric substrate; 1-3: coupling feeding structure; 1-3-1: first microstrip feeding line; 1-3-2: second microstrip feeding line; 1-3-3: circular patch; 1-3-4: feeding stub; 1-4: second dielectric substrate; 1-5: metal ground; 1-6: metal shorting post; 1-7: metal feeding post; 1-8: feeding port; 2: rectangular coupling stub. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be apparently and completely described below with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0026] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the present application will be further described in detail below with the drawings and specific embodiments.

[0027] The microstrip patch phased array antenna provided by the embodiments of the present application comprises: a plurality of microstrip patch antenna units 1 arranged in a grid at equal intervals and a plurality of rectangular coupling stubs 2. In an exemplary embodiment, as shown in Figure 1 The microstrip patch phased array antenna comprises 25 microstrip patch antenna units 1 arranged at equal intervals in a 5x5 grid.

[0028] For any microstrip patch antenna unit 1, as shown in Figure 2 The microstrip patch antenna unit 1 comprises, from top to bottom, a square radiation patch 1-1, a first dielectric substrate 1-2, a coupling feeding structure 1-3, a second dielectric substrate 1-4, a metal ground 1-5, a metal shorting post 1-6 and a metal feeding post 1-7; the square radiation patch 1-1 is located on the top surface of the center of the first dielectric substrate 1-2, the coupling feeding structure 1-3 is located between the second dielectric substrate 1-4 and the first dielectric substrate 1-2, and the two ends of the coupling feeding structure 1-3 are connected with the metal ground 1-5 through the metal shorting post 1-6 and the metal feeding post 1-7, respectively. As shown in Figure 3As shown, the metal shorting post 1-6 and the metal feeding post 1-7 both vertically pass through the second dielectric substrate 1-4. In this embodiment, the first dielectric substrate 1-2 and the second dielectric substrate 1-4 both adopt Rogers RT5880 material, with a relative dielectric constant of 2.2 and thicknesses of 2.286 mm and 0.254 mm, respectively.

[0029] A rectangular coupling branch 2 is arranged between any two microstrip patch antenna units 1, the rectangular coupling branch 2 has a same spacing with the two microstrip patch antenna units 1, the rectangular coupling branch 2 is located in the same plane with the square radiation patch 1-1 of each microstrip patch antenna unit 1, and the rectangular coupling branch 2 is symmetrically distributed about the adjacent two square radiation patches 1-1 to realize isotropic coupling regulation. The two long edges of the rectangular coupling branch 2 are parallel to the connecting line of the projection centers of the metal shorting post 1-6 and the metal feeding post 1-7 of any microstrip patch antenna unit 1 on the upper surface of the second dielectric substrate 1-4. The rectangular coupling branch 2 can regulate the near-field coupling strength between the antenna units 1 after optimization design, thereby enhancing the electromagnetic coupling energy transmission capability between the antenna units 1, and particularly, compensating the impedance mismatch problem of end-fire direction caused by phase tilt at a large angle scanning, and significantly improving the H-plane scanning stability.

[0030] Specifically, in this embodiment, as shown in Figure 2 The coupling feeding structure 1-3 includes a first microstrip feeding line 1-3-1, a second microstrip feeding line 1-3-2 and a circular patch 1-3-3. The first microstrip feeding line 1-3-1 is wider than the second microstrip feeding line 1-3-2. One end of the second microstrip feeding line 1-3-2 is connected to one end of the first microstrip feeding line 1-3-1, and the other end of the second microstrip feeding line 1-3-2 is connected to the circular patch 1-3-3. The circular patch 1-3-3 is located at the center lower surface of the first dielectric substrate 1-2, and is connected to the metal ground 1-5 through the metal shorting post 1-6 to form a short-circuit grounding structure. The other end of the first microstrip feeding line 1-3-1 away from the second microstrip feeding line 1-3-2 is connected to the feeding port 1-8 of the metal ground 1-5 through the metal feeding post 1-7 to realize coaxial feeding excitation.

[0031] In an alternative embodiment, the first microstrip feeding line 1-3-1 and the second microstrip feeding line 1-3-2 are both rectangular structures. In order to excite multi-resonant mode and widen the impedance bandwidth, in this embodiment, the part of the first microstrip feeding line 1-3-1 not coinciding with the square radiation patch 1-1 extends in the width direction with a plurality of feeding branches 1-3-4. The upper rectangular coupling branch 2 plays a role in improving the wide-angle scanning stability.

[0032] In one example embodiment of the present application, a plurality of microstrip patch antenna units 1 are arranged in an N x M rectangular grid, extending along the X and Y directions, N and M being the number of microstrip patch antenna units 1 in the X and Y directions respectively, N and M can be the same, and the arrangement can be in the form of an N x N rectangular grid. As shown in the figure, 5 x 5, which can be extended to 6 x 6, 6 x 7, 7 x 7, etc.

[0033] In the present embodiment, the center-to-center distance between two adjacent microstrip patch antenna units 1 in the X direction is 13.2 mm, and the center-to-center distance between two adjacent microstrip patch antenna units 1 in the Y direction is 12.3 mm. As shown in the figure, the overall size of the microstrip patch phased array antenna is 66 mm x 61.5 mm. The size of the square radiation patch 1-1 is 6.9 mm x 6.9 mm, the length of the rectangular coupling branch is 7.5 mm, the width is 2.4 mm, and the diameter of the metal short-circuit column is 0.67 mm. Figure 1

[0034] In another example embodiment of the present application, the simulation is performed in a full-wave electromagnetic simulation software using a radiation boundary condition, and the phase difference between the microstrip patch antenna units 1 is set to simulate different scanning angles of the beam in the E and H planes. The excitation signal is of the equal-amplitude variable-phase form to accurately evaluate the active standing wave ratio and the directional pattern characteristics of the antenna array under wide-angle scanning. The performance of the microstrip patch antenna unit 1 at the middle position of the microstrip patch phased array antenna shown in the figure is as shown in the figure. Figure 1 Figures 4 to 7 Figure 4 Figure 5 The active voltage standing wave ratio (Active VSWR) curves at different scanning angles in the E and H planes, respectively, are shown in the figures. Figure 6 Figure 7 The directional patterns of the microstrip patch phased array antenna in the E and H planes at 10 GHz, respectively, are shown in the figures.

[0035] Although the concept of the rectangular coupling branch 2 has certain applicability, its size and position need to be optimized in coordination with the resonant characteristics, current distribution, and scanning phase tilt of a specific antenna unit; the parameters of the rectangular coupling branch 2 used in the above-mentioned embodiments of the present application are specifically optimized for the microstrip patch antenna unit 1 shown in the figure. Figure 2 ​​​​​The illustrated microstrip patch antenna unit design is difficult to directly transplant to traditional narrowband patch or other types of antennas, otherwise it may cause mismatch and even performance deterioration.

[0036] But it should be noted that the skilled in the art can provide targeted optimization scheme for the antenna array of the application, fine-tune the antenna unit of the antenna array, including but not limited to adjusting the length of the feed line, the distance of the feed branch and the size of the patch, all of which can achieve the performance in this example, at this time, any technical variation made according to the technical scheme of the application falls within the scope of protection of the application.

[0037] Moreover, the technical features of the above different embodiments can be combined arbitrarily, in order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0038] The principles and implementation modes of the present application are described by applying specific examples in this paper, the above description of the examples is only used to help understand the method of the present application and its core idea; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In conclusion, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A microstrip patch phased array antenna, characterized in that, include: Several microstrip patch antenna elements arranged in a grid at equal intervals and several rectangular coupling stubs; For any microstrip patch antenna element, the microstrip patch antenna element includes, from top to bottom, a square radiating patch, a first dielectric substrate, a coupling feed structure, a second dielectric substrate, a metal ground, a metal short-circuit post perpendicularly penetrating the second dielectric substrate, and a metal feed post; the square radiating patch is located on the upper surface of the center of the first dielectric substrate, the coupling feed structure is located between the second dielectric substrate and the first dielectric substrate, and the two ends of the coupling feed structure are connected to the metal ground through the metal short-circuit post and the metal feed post, respectively; A rectangular coupling stub is provided between any two microstrip patch antenna elements. The rectangular coupling stub is spaced at the same distance from the two microstrip patch antenna elements. The rectangular coupling stub and the square radiating patch of each microstrip patch antenna element are located on the same plane. The two long sides of the rectangular coupling stub are parallel to the line connecting the projection center of the metal short-circuit post and the metal feed post of any microstrip patch antenna element on the upper surface of the second dielectric substrate.

2. The microstrip patch phased array antenna according to claim 1, characterized in that, The coupling feed structure includes a first microstrip feed line, a second microstrip feed line, and a circular patch. The first microstrip feed line is wider than the second microstrip feed line. One end of the second microstrip feed line is connected to one end of the first microstrip feed line, and the other end of the second microstrip feed line is connected to the circular patch. The circular patch is located on the lower surface of the center of the first dielectric substrate. The circular patch is connected to the metal ground through a metal short-circuit post to form a short-circuit ground structure. The end of the first microstrip feed line away from the second microstrip feed line is connected to the feed port of the metal ground through a metal feed post to achieve coaxial feed excitation.

3. The microstrip patch phased array antenna according to claim 2, characterized in that, Both the first microstrip feed line and the second microstrip feed line are rectangular structures.

4. The microstrip patch phased array antenna according to claim 3, characterized in that, The portion of the first microstrip feed line that does not overlap with the square radiating patch extends along the width direction with several feed branches.

5. The microstrip patch phased array antenna according to claim 1, characterized in that, Both the first dielectric substrate and the second dielectric substrate are made of Rogers RT5880 material, with a relative permittivity of 2.2 and thicknesses of 2.286 mm and 0.254 mm, respectively.

6. The microstrip patch phased array antenna according to claim 1, characterized in that, Several microstrip patch antenna elements are arranged in an N×M rectangular grid, extending along the X and Y directions, where N and M are the number of microstrip patch antenna elements in the X and Y directions, respectively.

7. The microstrip patch phased array antenna according to claim 1, characterized in that, Several microstrip patch antenna elements are arranged in an N×N rectangular grid, extending along the X and Y directions, where N is the number of microstrip patch antenna elements in the X and Y directions.

8. The microstrip patch phased array antenna according to claim 1, characterized in that, The center-to-center distance between two adjacent microstrip patch antenna elements in the X direction is 13.2 mm, and the center-to-center distance between two adjacent microstrip patch antenna elements in the Y direction is 12.3 mm.

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