A dual-polarized or circularly polarized microstrip antenna

Abstract

A dual-polarized or circularly polarized microstrip antenna employs a multi-layer stacked structure, comprising a feed layer, an upper dielectric substrate, a radiating layer, a prepreg layer, a lower dielectric substrate, and a ground layer connected sequentially from top to bottom. The upper dielectric substrate, radiating layer, prepreg layer, lower dielectric substrate, and ground layer are all square structures with chamfered corners. Rectangular slots are formed at the center edges of the four sides of the squares in the upper dielectric substrate, radiating layer, and prepreg layer. This invention introduces differential feeding, forming a ring structure with openings in the radiating layer and slots along ±45° directions. Radiation through these slots excites higher-order modes, resulting in higher gain. This antenna has a simple structure, is easy to manufacture, and offers significantly improved performance. It exhibits good impedance and gain bandwidth within the operating frequency band, low sidelobes, strong directivity, and high polarization purity. Furthermore, depending on the power divider applied, it can achieve either dual-polarized or circularly polarized operating modes.

Description

Technical Field

[0001] This invention belongs to the field of antenna design and manufacturing technology, specifically relating to a dual-polarized or circularly polarized microstrip antenna. Background Technology

[0002] Traditional communication technologies, such as base stations and Bluetooth, are often limited by geographical location, preventing users from receiving information in a timely manner. Satellite communication technology, however, can cover distances as far as 13,000 kilometers. For civilian communication systems, this method is not affected or limited by geographical conditions, natural disasters, or human-caused events between two points. The system is stable and reliable, has a large coverage area, and is relatively inexpensive. In the defense sector, satellite communication has immeasurable military application value, which has led to significant attention being paid to its development in recent years. The satellite antenna is responsible for transmitting and receiving information between the satellite system and the ground system. Therefore, the antenna's impedance bandwidth, axial ratio bandwidth, gain, elevation angle, and other parameters have a crucial impact on the accuracy of information reception and positioning precision between the satellite system and the ground terminal.

[0003] Satellite terminal antennas, as an indispensable part of wireless communication, play a crucial role in the transmission and reception of electromagnetic waves. The receiving antenna installed on the ground terminal converts the received electromagnetic waves into electrical signals for the input, while the transmitting antenna performs the opposite transformation. With the development of wireless communication technology and the widespread adoption of corresponding wireless products, especially handheld wireless communication devices and technologies, electronic devices are becoming increasingly powerful, and the requirements for signal functionality are also rising. Patch antennas have long been used due to their small size, low cost, and flexible feeding methods. In the context of applications such as satellite communication and global satellite navigation, circularly polarized waves have significant advantages over linearly polarized waves. Firstly, circularly polarized waves can receive waves of any polarization without considering positional effects. Secondly, their inherent rotational reversal characteristic perfectly solves problems commonly encountered in mobile communication, such as rain and fog, as well as multipath reflection. Therefore, high-performance circularly polarized patch antennas, which are low-cost, simple in structure, and easy to maintain, have significant research and application value. Meanwhile, dual-polarized antennas, due to their potential to increase channel capacity and combat multipath fading effects, are also widely used in various systems. Using dual-polarized antennas can reduce the number of antennas, save space resources required for antenna design, and meet the ever-increasing traffic demands.

[0004] Patent application document with publication number CN 114824724 A discloses a wideband, high-gain, low-axial-ratio circularly polarized microstrip antenna, which is constructed by stacking a square resonant patch, dielectric substrate A, slot layer, dielectric substrate B, and Wilkinson power divider from top to bottom. However, the shape of the resonant patch is not reasonable enough, and it fails to excite higher-order modes, with a gain of only 6dBi.

[0005] The patent application document with publication number CN114079153A discloses a microstrip dual-polarized antenna suitable for wireless power transmission, which adopts a parasitic patch method, but the structure is not reasonable enough and the gain is only 6dBi. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention aims to provide a dual-polarized or circularly polarized microstrip antenna. By introducing differential feeding, a ring structure is formed by opening holes in the radiating layer and slotting along the ±45° direction. Higher-order modes are excited through the radiating of the slots, thereby obtaining higher gain. This antenna has a simple structure, is easy to manufacture, and has significantly improved performance. It has good impedance bandwidth and gain bandwidth in the operating frequency band, low sidelobes, strong directivity, and high polarization purity. Furthermore, it can achieve different operating modes of dual polarization or circular polarization depending on the power divider loaded.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A dual-polarized or circularly polarized microstrip antenna adopts a multi-layer stacked structure, including a feed layer 10 with metal probes 11, an upper dielectric substrate 3, a radiating layer 5, a prepreg layer 12, a lower dielectric substrate 4, and a ground layer 1 connected sequentially from top to bottom.

[0009] The upper dielectric substrate 3, the radiation layer 5, the semi-cured sheet 12, the lower dielectric substrate 4, and the grounding layer 1 are all square with chamfered corners. Rectangular grooves 9 are provided at the center edges of the four sides of the square of the upper dielectric substrate 3, the radiation layer 5, and the semi-cured sheet 12.

[0010] The feed layer 10 includes a central ring 101, and four rectangular structures 102 connected to metal probes 11 are evenly distributed on the outer side of the central ring 101.

[0011] The radiation layer 5 is provided with four arc-shaped openings 6 arranged at 90 degrees. Rectangular openings 7 are provided between adjacent arc-shaped openings 6, and slits 8 are provided between opposite arc-shaped openings 6 in the ±45° direction.

[0012] The four sides of the square grounding layer 1 are all connected to short-circuit branches 2.

[0013] The short-circuit stub 2 is rectangular and bent inward at 90°.

[0014] The upper dielectric substrate 3, the radiation layer 5, and the semi-cured sheet 12 have the same chamfer size, and the lower dielectric substrate 4 and the grounding layer 1 have the same chamfer size. The chamfer size of the upper dielectric substrate 3, the radiation layer 5, and the semi-cured sheet 12 is not less than the chamfer size of the lower dielectric substrate 4 and the grounding layer 1.

[0015] The upper dielectric substrate 3, the radiation layer 5, and the semi-cured sheet 12 are all the same size; the lower dielectric substrate 4 and the grounding layer 1 are all the same size.

[0016] The metal probe 11 extends from the feed layer 10 to the ground layer 1.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The present invention uses two sets of differential feeds, namely, feeding to the feed layer 10 through the metal probe 11, and then differentially coupling the feed to the radiation layer 5. It can achieve dual polarization or circular polarization according to different power dividers, and at the same time, it can broaden the bandwidth.

[0019] 2. This invention forms a ring structure by opening an arc-shaped opening 6 in the radiation layer 5 and opening a slit 8 along the ±45° direction. The radiation structure of higher-order modes is excited through the slit radiation, which narrows the beam. At the same time, the sidelobe is suppressed by loading the resonant stub 2, so as to achieve a stable gain of more than 10dBi in the working frequency band, with a maximum of 14dBi.

[0020] In summary, the present invention has a simple and reasonable structure, low manufacturing cost, convenient installation and maintenance. While reducing costs, it can also effectively improve antenna performance, significantly improve and stabilize gain, and has good impedance bandwidth and gain bandwidth within the operating frequency band. It also has high polarization purity and strong directivity. Furthermore, it can be equipped with different power dividers to achieve two different operating modes: dual polarization or circular polarization. Attached Figure Description

[0021] Figure 1 This is a top view of the structure of the present invention.

[0022] Figure 2 This is an exploded side view of the present invention.

[0023] Figure 3 This is a side view structural diagram of the present invention.

[0024] Figure 4 This is a top-view dimension annotation comparison diagram of the present invention.

[0025] Figure 5 This is a side view dimension annotation comparison diagram of the present invention.

[0026] Figure 6 These are the active S11 curve and gain curve of the antenna in online polarization mode without short-circuit stubs.

[0027] Figure 7 This is the radiation pattern at 6.45 GHz of the antenna in online polarization mode without short-circuit stubs.

[0028] Figure 8 These are the active S11 curve and gain curve of the antenna designed in this invention under the online polarization operating mode.

[0029] Figure 9 This is the radiation pattern of the antenna designed in this invention at 6.45 GHz in the online polarization working mode.

[0030] Figure 10 These are the active S11 curve and gain curve of the antenna designed in this invention in circular polarization operating mode.

[0031] Figure 11 This is the radiation pattern of the antenna designed in this invention at 6.45 GHz in circular polarization mode.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1—Grounding layer; 2—Short-circuit stub; 3—Upper dielectric substrate; 4—Lower dielectric substrate; 5—Radiation layer; 6—Arc-shaped opening; 7—Rectangular opening; 8—Slotted along ±45° direction; 9—Rectangular groove; 10—Feeding layer; 101—Central ring; 102—Rectangular structure; 11—Metal probe; 12—Prepreg layer. Detailed Implementation

[0034] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0035] A dual-polarized or circularly polarized microstrip antenna employs a multi-layer stacked structure, comprising, from top to bottom, a feed layer 10 with a metal probe 11, an upper dielectric substrate 3, a radiating layer 5, a prepreg layer 12, a lower dielectric substrate 4, and a ground layer 1.

[0036] The upper dielectric substrate 3, the radiation layer 5, the semi-cured sheet 12, the lower dielectric substrate 4, and the grounding layer 1 are all square with chamfered corners. Rectangular grooves 9 are provided at the center edges of the four sides of the square of the upper dielectric substrate 3, the radiation layer 5, and the semi-cured sheet 12.

[0037] The feed layer 10 includes a central ring 101, and four rectangular structures 102 connected to metal probes 11 are evenly distributed on the outer side of the central ring 101.

[0038] The radiation layer 5 has four arc-shaped openings 6 arranged at 90 degrees. A rectangular opening 7 is provided between each adjacent arc-shaped opening 6, that is, there are four rectangular openings 7. A slit 8 is provided between the opposite arc-shaped openings 6 in the ±45° direction.

[0039] The four sides of the square grounding layer 1 are all connected to short-circuit branches 2.

[0040] The short-circuit stub 2 is rectangular and bent inward at 90°.

[0041] The upper dielectric substrate 3, the radiation layer 5, and the semi-cured sheet 12 have the same chamfer size, and the lower dielectric substrate 4 and the grounding layer 1 have the same chamfer size. The chamfer size of the upper dielectric substrate 3, the radiation layer 5, and the semi-cured sheet 12 is not less than the chamfer size of the lower dielectric substrate 4 and the grounding layer 1.

[0042] The upper dielectric substrate 3, the radiation layer 5, and the semi-cured sheet 12 are all the same size; the lower dielectric substrate 4 and the grounding layer 1 are all the same size.

[0043] The metal probe 11 extends from the feed layer 10 to the ground layer 1. The upper end of the metal probe 11 is connected to the feed layer 10, and the lower end is inserted into the opening, with its height flush with the feed layer 10.

[0044] like Figures 1 to 3 As shown, a dual-polarized or circularly polarized microstrip antenna employs a multi-layer stacked structure. From top to bottom, it consists of a feed layer 10 connecting four metal probes 11, an upper dielectric substrate 3, a radiating layer 5 with arc-shaped openings 6, rectangular openings 7, slots 8 along ±45° directions, and rectangular grooves 9 at the edges, a prepreg layer 12, a lower dielectric substrate 4, and a ground layer 1 connected to short-circuit stubs 2. The ground layer 1 is a square sheet with its four corners cut off, and the short-circuit stubs 2 are connected to the ground layer 1. The upper dielectric substrate 3 has its four corners cut off and rectangular grooves 9 along its edges, and the lower dielectric substrate 4 has its four corners cut off. The radiating layer 5 is metal, located below the upper dielectric substrate 3, and is a square sheet with its four corners cut off. The radiating layer 5 has arc-shaped openings 6, rectangular openings 7, slots 8 along ±45° directions, and rectangular grooves 9 at its edges. There are four metal probes 11, which are connected to the feed layer 10.

[0045] In this embodiment, as Figures 4 to 5 As shown, the grounding layer 1 has a side length W1=140mm, and four corners are chamfered with J1=55mm. The short-circuit branch 2 connected to it has a width W3=4.95mm, a height H2=7mm, and an inward bending depth L2=9.9mm. The upper dielectric board 3 and the lower dielectric board 4 are made of RT / duroid 5880 with a dielectric constant of 2.2 and a thickness H1=1.575mm. The upper dielectric board 3 has a side length W2=120mm, and four corners are chamfered with J3=35mm. A rectangular groove 9 with a depth L1=12mm and a width W4=22mm is cut along the center of the four sides. The lower dielectric board 4 has a side length W1=140mm and four corners are chamfered with J1=55mm.

[0046] The radiation layer 5 is made of metal with a side length of W2=120mm and four corners chamfered at J2=40mm. It has an arc-shaped opening 6 with an inner diameter of R2=23mm and an outer diameter of R3=34mm. It also has a rectangular opening 7 with a length of L3=21mm, a width of W6=3.5mm, and a distance from the center d1=6mm. A slit 8 is cut at the center along the ±45° direction to connect the opposing arc-shaped openings 6. The slit 8 has a width of W7=1mm. A rectangular groove 9 with a depth of L1=12mm and a width of W4=22mm is cut around the center of the perimeter.

[0047] The feed layer 10 is made of metal and consists of four rectangular structures 102 with a width W5=22mm and a length L4=13.8mm. These structures are connected by a central ring 101 with an inner diameter R1=15mm and an outer diameter R2=23mm. Four metal probes 11 are also connected to the rings. The metal probes 11 have a radius of 0.6mm, a height of H1+H1+H2=3.252mm, and a distance d2=4mm from the outer edge of the feed layer 10.

[0048] The semi-cured sheet 12 is made of RO4450F with a dielectric constant of 3.52, a thickness of H2=0.102mm, a side length of W2=120mm, and four corners with chamfers of J2=35mm. A rectangular groove 9 with a depth of L1=12mm and a width of W4=22mm is cut along the center of the perimeter.

[0049] Comparative Example

[0050] Compared to the antenna of this invention without short-circuit stub 2, simulation of its online polarization operating mode yields the following results: Figure 6 The active S11 curve and gain curve shown are Figure 7 The radiation pattern shown at 6.45 GHz indicates that the antenna's gain is too low, only 8 dB, in the 4.65 GHz-4.7 GHz range. This also reveals poor directivity. Therefore, the usable operating frequency band, i.e., the band with a gain above 10 dB, is only 4.7 GHz-4.83 GHz, which is too narrow.

[0051] like Figures 8 to 11 As shown, the antenna designed in this invention achieves a relative bandwidth of 4.7% (VSWR≤2), and its operating frequency band covers 4.61GHz-4.83GHz. Compared with existing antennas, the antenna of this invention has a simple structure, is easy to manufacture, and has improved performance, with a significant increase in gain. It also has good impedance matching characteristics within the operating frequency band; high polarization purity and low cross-polarization; high gain, which is maintained stably above 10dBi within the operating frequency band, reaching up to 14dBi. Furthermore, it can be paired with different power dividers to achieve two different operating modes: dual polarization or circular polarization, making it more versatile.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A dual-polarized or circularly polarized microstrip antenna employing a multi-layer stacked structure, characterized in that, It includes a feed layer (10) with metal probes (11) connected from top to bottom, an upper dielectric substrate (3), a radiation layer (5), a prepreg layer (12), a lower dielectric substrate (4), and a ground layer (1). The upper dielectric plate (3), radiation layer (5), semi-cured sheet (12), lower dielectric plate (4) and grounding layer (1) are all square four-corner cut-corner structures. Rectangular grooves (9) are opened at the center edge of the four sides of the square of the upper dielectric plate (3), radiation layer (5) and semi-cured sheet (12). The feed layer (10) includes a central ring (101), and four rectangular structures (102) connected to metal probes (11) are evenly distributed on the outer side of the central ring (101). The radiation layer (5) is provided with four arc-shaped openings (6) arranged at 90 degrees. Rectangular openings (7) are provided between adjacent arc-shaped openings (6), and slits (8) are provided between opposite arc-shaped openings (6) in the ±45° direction. The radiation layer (5) is fed differentially by a metal probe (11) to the feed layer (10), and dual polarization or circular polarization is achieved according to different power dividers.

2. A dual-polarized or circularly polarized microstrip antenna according to claim 1, characterized in that, The four sides of the square of the grounding layer (1) are all connected to short-circuit branches (2).

3. A dual-polarized or circularly polarized microstrip antenna according to claim 2, characterized in that, The short-circuit stub (2) is rectangular and bends inward at 90°.

4. A dual-polarized or circularly polarized microstrip antenna according to claim 1, characterized in that, The upper dielectric substrate (3), the radiation layer (5), and the semi-cured sheet (12) have the same chamfer size, and the lower dielectric substrate (4) and the grounding layer (1) have the same chamfer size. The chamfer size of the upper dielectric substrate (3), the radiation layer (5), and the semi-cured sheet (12) is not less than the chamfer size of the lower dielectric substrate (4) and the grounding layer (1).

5. A dual-polarized or circularly polarized microstrip antenna according to claim 1, characterized in that, The upper dielectric substrate (3), radiation layer (5) and semi-cured sheet layer (12) are the same size; the lower dielectric substrate (4) and grounding layer (1) are the same size.

6. A dual-polarized or circularly polarized microstrip antenna according to claim 1, characterized in that, The metal probe (11) extends from the feed layer (10) to the ground layer (1).

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