Ka-band high-gain quasi-parabolic patch antenna

Abstract

This invention discloses a Ka-band high-gain broadband microstrip patch antenna, primarily addressing the challenges of existing Ka-band antennas in simultaneously achieving broadband bandwidth and high gain, as well as their complex structures. It employs a stacked structure of a double-layer dielectric substrate, comprising, from top to bottom, a radiating patch, a first dielectric substrate, a metal ground plane, a second dielectric substrate, and a microstrip feed line. The radiating patch is a butterfly-like structure formed by cutting a square patch as a base and loading an anti-interference plate. A cross-shaped slot, formed by the orthogonal superposition of two identical H-shaped slots, is formed on the metal ground plane. The microstrip feed line achieves electromagnetic coupling with the radiating patch through this slot. This invention, through the coordinated design of patch and slot feeding, broadens the relative bandwidth and increases the maximum gain within the Ka-band, achieving an excellent balance between wide impedance bandwidth and high radiation gain. It also boasts advantages such as simple structure, easy fabrication, low cost, and easy integration, making it suitable for 5G millimeter-wave and satellite communication systems.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, specifically relating to a microstrip patch antenna that can be used in satellite communication, 5G / 6G millimeter-wave communication, and radar remote sensing. Background Technology

[0002] With the rapid development of 5G mobile communication and satellite communication technologies, the Ka band has attracted much attention due to its abundant spectrum resources. As a key component of the front-end of a communication system, antenna performance directly affects the overall system performance. Microstrip patch antennas, due to their advantages such as low profile, light weight, ease of integration, and conformal design, have become one of the preferred solutions for Ka band terminal antennas.

[0003] Patent document CN108736150B discloses a Ku / Ka band frequency-reconfigurable microstrip antenna, which consists of two dielectric substrates sandwiching a middle ground plane. The upper layer has a radiating patch, and the lower layer has a microstrip feed line, connected by a metal probe that is insulated from the ground plane. While this antenna achieves acceptable gain in the Ka band, its bandwidth is narrow, with a relative bandwidth of only 5.37%. Furthermore, the use of active switching elements increases the need for DC bias circuitry and control logic, leading to a complex structure, increased cost, and decreased reliability, making it difficult to meet the high data throughput requirements of broadband communication systems.

[0004] Patent document CN118040303A discloses a Ka-band broadband high-gain silicon-based antenna, which employs a complex stacked structure of multilayer silicon-based dielectric, double-layer radiating patch, BGA metal ball, and transition substrate, achieving broadband through the combination of two resonant points. Although this antenna achieves a relatively wide bandwidth, its gain is relatively low, with a maximum gain of only 5.33 dBi. Furthermore, its overall structure is extremely complex. Due to the involvement of multiple layers such as silicon oxide layers, insulating layers, air layers, BGA balls, and transition substrates, the manufacturing process is demanding and costly, hindering low-cost commercialization.

[0005] In summary, existing Ka-band microstrip antennas generally suffer from a trade-off between "acceptable gain with narrow bandwidth and low gain with wide bandwidth," making it difficult to achieve a good balance between wide bandwidth and high gain while maintaining a simple structure and ease of fabrication. Therefore, there is an urgent need for a Ka-band microstrip antenna that is simple in structure, easy to fabricate, inexpensive, and simultaneously possesses wide bandwidth and high gain characteristics. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the prior art by proposing a Ka-band high-gain broadband microstrip patch antenna, which simplifies the antenna structure, reduces costs, and simultaneously achieves wide bandwidth and high gain performance in the Ka-band, meeting the requirements of high-speed transmission, long-distance coverage, miniaturized integration, and low-cost commercial use for 5G millimeter wave and satellite communications.

[0007] The technical approach to achieving the objective of this invention is as follows: By controlling the surface current distribution through a butterfly-shaped radiating patch to improve radiation efficiency, and by introducing a multi-resonance mode through a strong-coupled feed with a cross-shaped slot on the metal ground plane, the technical problem of Ka-band microstrip antennas being unable to simultaneously achieve broadband and high gain is solved. By employing a passive stacked structure consisting of a double-layer dielectric substrate, a single-layer butterfly-shaped radiating patch, a cross-shaped slot metal ground plane, and a bottom microstrip feed line, and relying on conventional PCB manufacturing processes, the technical problems of complex antenna structure, high manufacturing cost, and difficulty in low-cost integration are solved.

[0008] Based on the above ideas, the technical solution of the present invention is as follows:

[0009] 1. A Ka-band high-gain broadband microstrip patch antenna, comprising a radiating patch 1, a first dielectric substrate 2, a metal ground plane 3, a second dielectric substrate 4, and a microstrip feed line 5 stacked together, characterized in that:

[0010] The radiation patch 1 adopts a butterfly-shaped structure to regulate the surface current distribution, broaden the bandwidth, and improve radiation efficiency and gain.

[0011] The metal floor 3 has two identical and orthogonal H-shaped cross-shaped slots 6 at its center for coupling the electromagnetic energy of the microstrip feed line 5 to the radiating patch 1.

[0012] Furthermore, the butterfly-like structure is based on a square patch, with an isosceles trapezoid cut off on its top and bottom sides respectively, and a semicircle cut off at the corresponding position of the short side of each isosceles trapezoid. At the same time, an isosceles right triangle is cut off at each of the four corners of the square patch, and rectangular anti-interference patches integrally formed with the patch extend outward from its left and right sides respectively, so as to form a butterfly-like structure similar to the shape of a butterfly.

[0013] Furthermore, the two H-shaped slits that form a cross-shaped arrangement each have a main vertical section with a length of 3.4mm to 3.5mm and a width of 0.15mm to 0.16mm, and the horizontal sections at both ends of the main vertical section each have a length of 0.4mm to 0.5mm and a width of 0.15mm to 0.16mm.

[0014] Furthermore, the radiating patch 1 is laid on the upper surface of the first dielectric substrate 2; the metal ground plane 3 is sandwiched between the first dielectric substrate 2 and the second dielectric substrate 4; and the microstrip feed line 5 is laid on the lower surface of the second dielectric substrate 4.

[0015] Furthermore, the geometric center of the cross-shaped gap coincides with the geometric centers of the metal floor, the radiant patch, the first dielectric plate, and the second dielectric plate, and the distance from the geometric center of the cross-shaped gap to the edge of the metal floor is 2.613mm to 2.888mm, and the distance from the geometric center of the radiant patch to the edge of the radiant patch is 1.14mm to 1.26mm.

[0016] Compared with the prior art, the present invention has the following obvious substantive features and significant advantages: firstly, high gain and broadband characteristics.

[0017] This invention effectively regulates the current distribution on the patch surface and improves radiation efficiency through a unique butterfly-shaped radiating patch structure. Simultaneously, combined with a strong-coupled feeding method using a cross-shaped slot, multiple resonant modes are introduced, enabling the antenna to achieve a relative bandwidth of 9.56% in the 24-26 GHz band, with a maximum gain of 6.11 dBi at the center frequency of 25 GHz, successfully balancing broadband and high-gain performance. Secondly, the structure is simple and easy to manufacture.

[0018] This invention employs a classic passive structure consisting of a double-layer dielectric substrate, a single-layer surface mount, a single-layer gap ground, and a single-layer microstrip feeder. It does not involve any active switching devices or complex multilayer transition substrates. The overall structure is simple and can be implemented using standard PCB or microwave dielectric substrate processing technology, resulting in low processing costs and high yield. Thirdly, it is easy to integrate.

[0019] This invention employs microstrip line feeding, with the feed line located at the bottom layer, allowing direct integration with RF front-end circuits without the need for additional transition structures. Furthermore, the overall planar dimensions are only 5.5mm × 5.5mm, and the profile height is ≤2.4mm. This low-profile, miniaturized design facilitates easy integration with RF front-end circuits. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of a Ka-band high-gain butterfly-shaped patch antenna provided in an embodiment of the present invention.

[0021] Figure 2 This is a top view schematic diagram of a Ka-band high-gain broadband microstrip patch antenna according to an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the metal ground plane slot structure in the Ka-band high-gain broadband microstrip patch antenna according to an embodiment of the present invention.

[0023] Figure 4 The figure shows the simulation results of the return loss S11 of the Ka-band high-gain broadband microstrip patch antenna according to an embodiment of the present invention.

[0024] Figure 5The figure shows the simulation results of the radiation gain of the Ka-band high-gain broadband microstrip patch antenna according to an embodiment of the present invention. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention and not all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative effort should all fall within the protection scope of the present invention.

[0026] Reference Figure 1 The Ka-band high-gain butterfly-shaped patch antenna of the present invention includes a radiating patch 1, a first dielectric substrate 2, a metal ground plane 3, a second dielectric substrate 4, and a microstrip feed line 5 stacked together. Specifically: the radiating patch 1 is disposed on the upper surface of the first dielectric substrate 2; the metal ground plane 3 is sandwiched between the first dielectric substrate 2 and the second dielectric substrate 4; the microstrip feed line 5 is disposed on the lower surface of the second dielectric substrate 4, and has a cross-shaped slot at its center, the geometric center of which coincides with the geometric centers of the metal ground plane 3, the radiating patch 1, the first dielectric substrate 2, and the second dielectric substrate 4.

[0027] Reference Figure 2 The radiation patch 1 adopts a butterfly-like structure. It is based on a square patch, with an isosceles trapezoid cut off on the top and bottom sides of the base, and a semicircle cut off at the corresponding position of the short side of each isosceles trapezoid. At the same time, an isosceles right triangle is cut off at each of the four corners of the square patch, and rectangular anti-interference patches integrally formed with the patch extend outward from the left and right sides to form a butterfly-like structure.

[0028] Reference Figure 3 The metal floor 3 has two identical and orthogonal H-shaped cross-shaped slots 6 at its center for coupling the electromagnetic energy of the microstrip feed line 5 to the radiating patch 1.

[0029] The following are three embodiments of the Ka-band high-gain butterfly-shaped patch antenna of the present invention with different parameters:

[0030] Example 1: This example simulates an antenna with a center frequency of 25 GHz. The antenna has two dielectric substrates. The first dielectric substrate 2 is made of Rogers RT / duroid 5880 with a relative permittivity of 2.2 and has dimensions of 5.5 mm * 5.5 mm * 1 mm. The second dielectric substrate 4 is made of Rogers RO4003 with a relative permittivity of 3.55 and has dimensions of 5.5 mm * 5.5 mm * 0.254 mm.

[0031] A butterfly-shaped structure is applied to the surface of the radiating patch 1 on the first dielectric substrate 2 to regulate the surface current distribution, broaden the bandwidth, and improve radiation efficiency and gain. Its square base has a side length of 2.4 mm, and isosceles trapezoids are cut off on the top and bottom sides, with the long side of each trapezoid being 2 mm and the short side 0.4 mm.

[0032] The semicircles cut off at the corresponding positions of the short sides of each isosceles trapezoid have a radius of 0.2 mm.

[0033] Isosceles right triangles, each with a side length of 0.1 mm, were cut out from the four corners of the square patch.

[0034] Rectangular anti-interference patches, integrally formed with the square patch, extend outward from both the left and right sides of the patch. These patches are 0.75mm long and 0.16mm wide.

[0035] Two identical and orthogonal H-shaped cross-shaped slots 6 are formed at the center of a metal ground plane 3 sandwiched between the first dielectric substrate 2 and the second dielectric substrate 4. The main vertical section of each slot is 3.5 mm long and 0.16 mm wide, while the horizontal sections at both ends of each main vertical section are 0.5 mm long and 0.16 mm wide. This is to couple the electromagnetic energy of the microstrip feed line 5 to the radiating patch 1.

[0036] The distance from the geometric center of the cross-shaped gap to the edge of the metal floor is 2.75 mm, and the distance from the geometric center of the radiant patch to the edge of the radiant patch is 1.2 mm.

[0037] The microstrip feed line 5, which is laid on the lower surface of the second dielectric substrate 4, has a size of 5.5mm*0.254mm.

[0038] The performance of the antenna in this example, operating in the Ka band, was simulated at a center frequency of 25 GHz. The results are as follows: Figure 4 and Figure 5 As shown.

[0039] from Figure 4 As can be seen, the bandwidth loss in this example is 2.21 GHz, and the relative bandwidth is 9.56%.

[0040] from Figure 5 As can be seen, the maximum gain of the antenna in this example is 6.11 dBi.

[0041] Example 2: This example simulates an antenna with a center frequency of 25 GHz. The antenna has two dielectric substrates. The first dielectric substrate 2 is made of Rogers RT / duroid 5880 with a relative permittivity of 2.2 and has dimensions of 5.5 mm * 5.5 mm * 0.9 mm. The second dielectric substrate 4 is made of Rogers RO4003 with a relative permittivity of 3.55 and has dimensions of 5.5 mm * 5.5 mm * 0.2 mm.

[0042] The butterfly-shaped structure of the radiating patch 1 laid on the upper surface of the first dielectric substrate 2 has a square base with a side length of 2.3 mm, and isosceles trapezoids cut off on the upper and lower sides, with a long side of 1.9 mm and a short side of 0.38 mm.

[0043] The semicircles cut off at the corresponding positions of the short sides of each isosceles trapezoid have a radius of 0.19 mm.

[0044] Isosceles right triangles, each with a side length of 0.1 mm, were cut out from the four corners of the square patch.

[0045] Rectangular anti-interference patches, integrally formed with the square patch, extend outward from both the left and right sides of the patch. These patches are 0.73mm long and 0.15mm wide.

[0046] Two identical and orthogonal H-shaped cross-shaped slots 6 are opened at the center of the metal ground plane 3 sandwiched between the first dielectric substrate 2 and the second dielectric substrate 4. The main vertical section of each slot is 3.4 mm long and 0.15 mm wide, and the horizontal sections at both ends of each main vertical section are 0.4 mm long and 0.15 mm wide, so as to couple the electromagnetic energy of the microstrip feed line 5 to the radiating patch 1.

[0047] The distance from the geometric center of the cross-shaped gap to the edge of the metal floor is 2.613 mm, and the distance from the geometric center of the radiant patch to the edge of the radiant patch is 1.14 mm.

[0048] The microstrip feed line 5, laid on the lower surface of the second dielectric substrate 4, achieves 50-ohm characteristic impedance matching and has a size of 5.5mm*0.251mm.

[0049] With a center frequency of 25 GHz, the performance of the antenna in this example is simulated when it operates in the Ka band. Its relative bandwidth is 9.42% and the maximum gain of the antenna is 6.06 dBi.

[0050] Example 3: The antenna in this example has two dielectric substrates. The first dielectric substrate 2 is made of Rogers RT / duroid 5880 with a relative permittivity of 2.2 and has dimensions of 5.5mm*5.5mm*1.05mm. The second dielectric substrate 4 is made of Rogers RO4003 with a relative permittivity of 3.55 and has dimensions of 5.5mm*5.5mm*0.245mm.

[0051] The butterfly-shaped structure of the radiating patch 1 laid on the upper surface of the first dielectric substrate 2 has a square base with a side length of 2.35 mm and isosceles trapezoids cut off on the upper and lower sides, with a long side of 2.10 mm and a short side of 0.42 mm.

[0052] The semicircles cut off at the corresponding positions of the short sides of each isosceles trapezoid have a radius of 0.21 mm.

[0053] The isosceles right triangles cut from the four corners of the square patch each have a leg length of 0.105 mm.

[0054] Rectangular anti-interference patches, integrally formed with the square patch, extend outward from both the left and right sides of the patch. These patches are 0.71 mm long and 0.168 mm wide.

[0055] The metal ground plane 3, sandwiched between the first dielectric substrate 2 and the second dielectric substrate 4, has two identical and orthogonal H-shaped cross-shaped slots 6 at its center. The main vertical section of each slot is 3.675 mm long and 0.168 mm wide, and the horizontal sections at both ends of each main vertical section are 0.525 mm long and 0.168 mm wide, in order to couple the electromagnetic energy of the microstrip feed line 5 to the radiating patch 1.

[0056] The distance from the geometric center of the cross-shaped gap to the edge of the metal floor is 2.88 mm, and the distance from the geometric center of the radiant patch to the edge of the radiant patch is 1.26 mm.

[0057] The microstrip feed line 5, which is laid on the lower surface of the second dielectric substrate 4, has a size of 5.5mm*0.267mm.

[0058] The performance of the antenna in this example, operating in the Ka band, was simulated with a center frequency of 25 GHz. The relative bandwidth was 9.12%, and the maximum gain of the antenna was 5.92 dBi.

[0059] Simulation results show that the antenna of this invention achieves stable and reliable electrical performance in a Ka-band operating scenario with a center frequency of 25 GHz, with a relative bandwidth of 9.12% to 9.56% and a maximum gain of 5.92 dBi to 6.11 dBi. Compared with existing Ka-band antenna technologies, this invention, using only a passive planar structure with a conventional double-layer dielectric substrate, overcomes the technical bottleneck of "difficulty in balancing bandwidth and gain" commonly found in existing technologies, achieving an excellent balance between wide impedance bandwidth and high radiation gain, fully meeting the core application requirements of Ka-band commercial scenarios such as 5G millimeter-wave communication and satellite communication.

[0060] The above descriptions are merely three specific examples of the present invention and do not constitute any limitation on the present invention. Obviously, those skilled in the art, after understanding the content and principles of the present invention, may make various modifications and changes in form and detail without departing from the principles and structure of the present invention, including:

[0061] Regarding the selection of dielectric substrate materials, in addition to Rogers RT / duroid 5880 as the first dielectric substrate and Rogers RO4003 as the second dielectric substrate selected in the embodiments of this invention, it can also be replaced with commonly used dielectric materials in the microwave field such as PTFE-based high-frequency composite dielectric boards, ceramic substrates, and high-frequency FR-4 plates of the same dielectric constant range from brands such as Taconic and Arlon, depending on the application scenario, processing cost, and performance requirements. The thickness of the dielectric substrate can also be adaptively adjusted within the numerical range disclosed in this example, as long as the impedance matching and coupling feeding effect of the antenna can be guaranteed.

[0062] In terms of the structural design of the radiating patch, the geometric cut of the butterfly-shaped structure can be adapted. For example, the isosceles trapezoids on the top and bottom sides of the square base in this example can be replaced with right trapezoids or triangular grooves. The semicircular cut at the short side of the trapezoid can also be replaced with a rectangular groove. The isosceles right triangle cuts at the four corners of the base can be replaced with rounded corners or beveled corners. The rectangular anti-interference patches on both sides can be replaced with trapezoidal or arc-shaped anti-interference branches. At the same time, the overall size of the patch can be scaled proportionally according to the target operating frequency to adapt to different operating sub-bands in the Ka band. Any design that controls the surface current distribution of the patch, broadens the bandwidth, and improves the gain through geometric cutting is permissible.

[0063] Regarding the structural design of the coupling feed gap, the cross-shaped gap is not limited to the superposition structure of two orthogonal H-shaped gaps described in this embodiment. The end structure of the H-shaped gap can be adaptively adjusted. For example, the rectangular horizontal segments at both ends can be replaced with arc-shaped or trapezoidal branches. The length and width of the gap can be adaptively optimized within the numerical range disclosed in this invention. Tuning branches can also be added to the edge of the gap to further expand the bandwidth. The design of electromagnetic coupling feed and introduction of multiple resonant modes can be realized through the orthogonally superimposed gap structure.

[0064] However, the above-mentioned modifications and alterations based on the ideas of this invention are still within the scope of protection of the claims of this invention.

Claims

1. A Ka-band high-gain broadband microstrip patch antenna, comprising a radiating patch 1, a first dielectric substrate 2, a metal ground plane 3, a second dielectric substrate 4, and a microstrip feed line 5 stacked together, characterized in that: The radiation patch 1 adopts a butterfly-shaped structure to regulate the surface current distribution, broaden the bandwidth, and improve radiation efficiency and gain. The metal floor 3 has two identical and orthogonal H-shaped cross-shaped slots 6 at its center for coupling the electromagnetic energy of the microstrip feed line 5 to the radiating patch 1.

2. The antenna according to claim 1, characterized in that, The butterfly-like structure is based on a square patch, with an isosceles trapezoid cut off on its top and bottom sides, and a semicircle cut off at the corresponding position of the short side of each isosceles trapezoid. At the same time, an isosceles right triangle is cut off at each of the four corners of the square patch, and rectangular anti-interference patches integrally formed with the patch extend outward from its left and right sides to form a butterfly-like structure.

3. The antenna according to claim 1, characterized in that, The two H-shaped slits that form a cross shape each have a main vertical section with a length of 3.4mm to 3.7mm and a width of 0.15mm to 0.168mm, and the horizontal sections at both ends of the main vertical section each have a length of 0.4mm to 0.6mm and a width of 0.15mm to 0.168mm.

4. The antenna according to claim 1, characterized in that: The radiation patch 1 is applied to the upper surface of the first dielectric substrate 2; The metal floor 3 is sandwiched between the first dielectric substrate 2 and the second dielectric substrate 4; The microstrip feed line 5 is laid on the lower surface of the second dielectric substrate 4.

5. The antenna according to any one of claims 1-4, characterized in that: The geometric center of the cross-shaped gap coincides with the geometric centers of the metal floor, the radiant patch, the first dielectric plate, and the second dielectric plate. The distance from the geometric center of the cross-shaped gap to the edge of the metal floor is 2.613mm to 2.888mm, and the distance from the geometric center of the radiant patch to the edge of the radiant patch is 1.14mm to 1.26mm.

6. The antenna according to claim 2, characterized in that: The square patch has a side length of 2.3mm to 2.4mm; The isosceles trapezoid has a short side length of 0.38mm to 0.42mm and a long side length of 1.9mm to 2.1mm. The radius of the semicircle is 0.19 mm to 0.2 mm; The leg length of the isosceles right triangle is 0.095mm to 0.105mm; The rectangular anti-interference sheet has a length of 0.71mm to 0.75mm and a width of 0.15mm to 0.168mm.

7. The antenna according to claim 1, characterized in that: The first dielectric substrate uses Rogers RT / duroid 5880 material with a relative permittivity of 2.2 and a thickness of 0.9 mm to 1.1 mm; The second dielectric substrate uses Rogers RO4003 material with a relative permittivity of 3.55 and a thickness of 0.2 mm to 0.254 mm.

8. The antenna according to claim 1, characterized in that, The microstrip feed line is a long rectangular metal strip with a width of 0.251 mm to 0.267 mm to achieve 50 ohm characteristic impedance matching.

Images