Low profile multi-mode antenna

Abstract

The application discloses a kind of low profile multi-mode antennas, belong to antenna technical field.It includes circular patch, sector patch, PCB substrate, metal ground layer, metallized via, metallized via, metallized via and feed network, metal ground layer avoidance hole etc.composition, coaxial connector is provided at feed point;Through the electromagnetic coupling design of circular patch and sector patch on the upper surface of PCB substrate, the antenna bandwidth is widened, and the optimization design of antenna multi-mode is realized by feed network and multiple metallized via.The overall profile height of the antenna is 2mm, which is only 0.022lambda max, the antenna has two feed points, can realize low profile circularly polarized directional antenna radiation mode, and the working frequency band is 3.35GHz-3.53GHz;It can also realize low profile omnidirectional antenna radiation mode, and the working frequency band is 4.66GHz-5.33GHz.The antenna structure is compact, has good wideband characteristics, low cost, light weight, easy to mass production and other characteristics, and can be applied to ground communication and detection field.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a low-profile multimode antenna. Background Technology

[0002] With the maturity of single-band antenna technology and the widespread application of wireless communication networks, research has shifted its focus to dual-band or multi-band antennas. The wireless market urgently demands that radar, mobile communication, and satellite positioning systems utilize frequency reuse with multi-band antennas to address the increasingly congested microwave spectrum. Methods for obtaining dual-band or multi-band characteristics include single-layer, multi-layer, and multi-mode methods. While multiple single-band antennas can be used to cover different frequency bands in a communication system, this increases the size and weight of the antennas and wireless systems, raising costs and contradicting the trend towards miniaturization and cost reduction in wireless equipment.

[0003] For antennas in certain communication systems, it is generally desirable to have advantages such as multi-band and multi-mode operation, small size, low profile, and light weight. Therefore, designing multi-mode antennas capable of operating in multiple frequency bands has certain practical value and significance. Published literature reports on dual-band and tri-band antennas. These are mostly stacked or flat-lay common-aperture antennas. Their multi-frequency operating modes are mostly either entirely directional or entirely omnidirectional, resulting in a large overall antenna size or profile height, which is not conducive to practical engineering applications.

[0004] Currently, most multimode antennas are planar antennas, mainly composed of one or more printed circuit boards. Multiple modules can be mounted on this board, each with different functions. Because of this, each module needs to occupy a certain area on the printed circuit board, resulting in a sometimes large circuit board area, which is detrimental to the design and fabrication of multimode antennas. Furthermore, while existing literature and patents mention some multimode antennas, there are few publicly reported low-profile multimode antennas that achieve both omnidirectional radiation at a certain frequency and conical directional radiation at another frequency. Summary of the Invention

[0005] In view of this, the present invention proposes a low-profile multimode antenna that can operate in both high-frequency and low-frequency bands. It achieves directional radiation in the low-frequency band and directional radiation in the high-frequency band, thus realizing both omnidirectional and directional radiation operating modes with a single antenna, enabling good information exchange with specific targets or specific areas.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A low-profile multimode antenna includes a metallic ground layer, an upper printed circuit board, and a lower printed circuit board; the upper surface of the upper printed circuit board is provided with a central patch and an array patch, the central patch is located at the center of the upper printed circuit board, and the array patch is provided with 4 patches arranged in a circle with the central patch as the center.

[0008] The metal ground layer is located between the upper and lower printed circuit boards. The lower surface of the lower printed circuit board is provided with a power supply network in the form of a 1-to-4 Wilkinson power divider. Each array patch has a first metallized via below it. One end of the first metallized via is connected to the array patch above it, and the other end passes through the metal ground layer and is connected to the corresponding branch end of the power supply network. The center patch has a second metallized via and multiple third metallized vias below it. One end of the second metallized via is connected to the center of the center patch, and the other end passes through the metal ground layer and is exposed on the lower printed circuit board. The multiple third metallized vias are evenly arranged with the second metallized via as the center. One end of the third metallized via is connected to the center patch, and the other end is connected to the upper surface of the metal ground layer.

[0009] Furthermore, there is no contact between the array patches or between the array patches and the center patch.

[0010] Furthermore, the central patch is circular, and the array patches are fan-shaped; the inner diameter of the array patches is larger than the diameter of the central patch.

[0011] Furthermore, neither the first metallized via nor the second metallized via is in contact with the metal formation.

[0012] Furthermore, it also includes two coaxial connectors, one of which has its inner center conductor connected to a second metallized through-hole and its outer conductor connected to a metal ground layer; the other coaxial connector has its inner center conductor connected to the main path of the power supply network and its outer conductor connected to a metal ground layer.

[0013] Furthermore, the first metallized through-hole, the second metallized through-hole, and the third metallized through-hole can all be equivalently replaced by metal pillars. Attached Figure Description

[0014] Figure 1 A low-profile multimode antenna structure diagram provided in an embodiment of the present invention;

[0015] Figure 2 A perspective view of a low-profile multimode antenna from top to bottom, provided for an embodiment of the present invention;

[0016] Figure 3 A schematic diagram of the cross-sectional structure of a low-profile multimode antenna provided in an embodiment of the present invention;

[0017] Figure 4This is a diagram of the upper structure of a low-profile multimode antenna provided in an embodiment of the present invention;

[0018] Figure 5 This is a diagram of the middle layer structure of a low-profile multimode antenna provided in an embodiment of the present invention;

[0019] Figure 6 This is a diagram of the lower layer structure of a low-profile multimode antenna provided in an embodiment of the present invention;

[0020] Figure 7 A voltage standing wave ratio (VSWR) curve for the omnidirectional radiation mode frequency band provided in an embodiment of the present invention;

[0021] Figure 8 The gain pattern at 4.66 GHz in the omnidirectional radiation mode provided in this embodiment of the invention;

[0022] Figure 9 The gain pattern at 4.995 GHz in the omnidirectional radiation mode provided in this embodiment of the invention;

[0023] Figure 10 The gain pattern at 5.33 GHz in the omnidirectional radiation mode provided in this embodiment of the invention;

[0024] Figure 11 A voltage standing wave ratio (VSWR) curve for the directional radiation mode frequency band provided in an embodiment of the present invention;

[0025] Figure 12 A circular polarization axial ratio curve for the directional radiation mode frequency band provided in an embodiment of the present invention;

[0026] Figure 13 Gain pattern at 3.35 GHz frequency for directional radiation mode provided in an embodiment of the present invention;

[0027] Figure 14 Gain pattern at 3.44 GHz frequency for directional radiation mode provided in an embodiment of the present invention;

[0028] Figure 15 Gain pattern of directional radiation mode at 3.53 GHz frequency band provided in an embodiment of the present invention.

[0029] Figure labeling: 1-Circular patch; 2-Fan-shaped patch; 3-PCB substrate; 4-Ground layer; 5-Metalized via; 6-Metalized via; 7-Metalized via; 8-Power supply network; 9-Ground clearance hole. Detailed Implementation

[0030] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent.

[0031] It is understandable to those skilled in the art that certain well-known structures and their descriptions may be omitted in the accompanying drawings;

[0032] To illustrate the structure and features of the present invention in detail, the technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] A low-profile multimode antenna is formed by laminating multiple printed circuit boards and uses a top circular patch and a fan-shaped patch for electromagnetic coupling design, which broadens the antenna bandwidth. The antenna multimode is optimized through a feed network and multiple metallized vias.

[0034] A low-profile multimode antenna has two feed points, enabling it to achieve both a low-profile circularly polarized directional antenna radiation mode (operating in the 3.35 GHz–3.53 GHz band) and a low-profile omnidirectional antenna radiation mode (operating in the 4.66 GHz–5.33 GHz band). The antenna's overall profile height is only 2 mm, with a maximum diameter of 0.022λmax. This low-profile multimode antenna features dual-band operation, low profile, light weight, and ease of mass production. In the vertically polarized omnidirectional radiation mode, it exhibits a voltage standing wave ratio (VSWR) of less than 2.0 and a gain greater than 0 dBi. In the circularly polarized directional radiation mode, it has a VSWR of less than 2.0, a circular polarization axial ratio of less than 3 dB, and a gain greater than 4 dBi.

[0035] This embodiment includes a circular patch 1, a fan-shaped patch 2, a PCB substrate 3, a metal ground layer 4, metallized vias 5, 6, and 7, a power supply network 8, and metal ground clearance vias 9. (See details...) Figure 1 and Figure 2 .

[0036] The circular patch 1 is circular in shape and located on the upper surface of the PCB substrate 3, at its center. The circular patch 1 has 13 circular metallized vias 5 and 1 circular metallized via 6, with the circular metallized via 6 located at the exact center of the circular patch 1. The metallized vias 5 are evenly distributed around the metallized via 6. Figure 1 and Figure 4 .

[0037] Furthermore, the fan-shaped patches 2 are located on the upper surface of the PCB substrate 3. There are a total of 4 fan-shaped patches 2, which are not in contact with each other and are evenly distributed around the circular patch 1. Each fan-shaped patch 2 has a circular metallized through-hole 7 on its surface. Figure 1 and Figure 4 .

[0038] Furthermore, the PCB substrate 3 is a multilayer printed circuit board, consisting of three layers, as shown in [reference needed]. Figure 3 The upper layer consists of a metal cladding layer of circular patch 1 and fan-shaped patch 2, see... Figure 2 and Figure 4 The middle layer is a metallic stratum 4, which includes 5 metallic stratum avoidance boreholes 9, see... Figure 2 and Figure 5 The lower layer is the power supply network layer, see... Figure 2 and Figure 6 .

[0039] Furthermore, the metal ground layer 4 is located in the middle layer of the PCB board and is connected to the circular patch 1 through 13 metallized vias 5, see... Figure 3 .

[0040] Furthermore, the power supply network 8 is located on the bottom layer of the PCB board, employs a 1-to-4 Wilkinson power divider, and is connected to four fan-shaped patches 2 through four metallized vias 7, passing through four metal ground plane clearance holes 9, without contacting the metal ground plane 4. Figure 3 .

[0041] The dimensions of each part are explained further below:

[0042] See Figure 1 and Figure 2 , Figure 1 This is a low-profile multimode antenna structure diagram of the present invention. Figure 2 This is a perspective view of a low-profile multimode antenna from top to bottom. The low-profile multimode antenna includes a circular patch 1, a fan-shaped patch 2, a PCB substrate 3, a metal ground layer 4, a metallized via 5, a metallized via 6, a metallized via 7, a feed network 8, and a metal ground layer clearance hole 9.

[0043] In this embodiment, the circular patch 1 is circular in shape with a diameter of 42.6 mm, located on the upper surface of the PCB substrate 3, and at its center. The circular metallized via 6 has a diameter of 1.1 mm, is located at the exact center of the circular patch 1, and penetrates both the upper and lower surfaces of the PCB substrate. There are 13 metallized vias 5 with a diameter of 1.2 mm each, with an included angle of 13° / 360° between adjacent vias. These 13 metallized vias 5 are evenly distributed around the center of the circular patch 1 on a circle with a radius of 14.7 mm. Figure 1 and Figure 4 .

[0044] In this embodiment, the fan-shaped patches 2 are fan-shaped, totaling four, with no contact between any two. They are all located on the upper surface of the PCB substrate 3, on the same plane as the circular patches 1, and evenly distributed around the perimeter of the circular patches 1. The maximum outer diameter of the fan-shaped patches 2 is 50mm, and the inner diameter is 23mm. The spacing between two adjacent fan-shaped patches 2 is 10mm, and the spacing between them and the circular patches 1 is 1.7mm. Each fan-shaped patch 2 has a circular metallized via 7 on its surface. The diameter of the circular metallized via 7 is 1mm, and the circular metallized via 7 is located on the center line of the fan-shaped patch 2, with a distance of 32mm from the center of the circular patch 1. Figure 1 and Figure 4 .

[0045] In this embodiment, the PCB substrate 3 is a multilayer printed circuit board, consisting of three layers, as shown below. Figure 3 The printed circuit board is circular with a diameter of 50mm, using Neltec NY9260(IM)(tm) board material with a dielectric constant of 2.6. The overall thickness of PCB substrate 3 is 2mm, with a distance of 1.5mm between the top and middle layers and 0.5mm between the middle and bottom layers. The top layer consists of a metal cladding layer for circular patch 1 and fan-shaped patch 2, see [details omitted]. Figure 2 and Figure 4 The middle layer is a metallic stratum 4, which includes 5 metallic stratum avoidance boreholes 9, see... Figure 2 and Figure 5 The lower layer is the power supply network layer, see... Figure 2 and Figure 6 .

[0046] In this embodiment, the metal ground layer 4 is circular in shape with a diameter of 50mm, located in the middle layer of the PCB board, and connected to the circular patch 1 through 13 metallized vias 5. The metal ground layer 4 has 5 metal ground layer clearance holes 9, each with a diameter of 4.0mm and a distance of 32mm from its center. These clearance holes are positioned at the same horizontal cross-section as the circular metallized vias 7. The function of the metal ground layer clearance holes 9 is to prevent the circular metallized vias 7 and 6 from connecting to the metal ground layer 4, thus preventing short circuits. See [link / reference] Figure 3 and Figure 5 .

[0047] In this embodiment, the power supply network 8 is located on the bottom layer of the PCB board, and the lower surface metal cladding is the power supply network line, see... Figure 6 It employs a 1-to-4 Wilkinson power divider, serving both power division and phase shifting functions. It connects to four fan-shaped patches 2 via four metallized vias 7, passing through four metal ground plane clearance holes 9, without contacting the metal ground plane 4. (See...) Figure 3 .

[0048] In this embodiment, there are two coaxial connectors, located at the center of the lower surface of the PCB substrate and the starting position of the feed network 8, respectively, for feeding the feed network 8 and the antenna. One coaxial connector has its inner conductor connected to the metallized via 6 and its outer conductor connected to the metal ground plane. The other coaxial connector has its inner conductor connected to the main path of the feed network and its outer conductor connected to the metal ground plane. See [link to documentation]. Figure 3 .

[0049] In this embodiment, Figure 7 The voltage standing wave ratio (VSWR) curve for the omnidirectional radiation mode frequency band provided in this embodiment of the invention is shown below. Figure 7 It is known that the omnidirectional radiation mode operates within a frequency band of 4.66 GHz to 5.33 GHz, with a voltage standing wave ratio (VSWR) of less than 2.0, giving the antenna good impedance characteristics within the omnidirectional radiation mode frequency band. The VSWR can be optimized by adjusting the number and position of the metallized vias 5, and the size of the circular patch 1 can also be adjusted to optimize the VSWR.

[0050] In this embodiment, Figures 8-10 The gain pattern of the omnidirectional radiation mode frequency band provided in the embodiments of the present invention is from... Figures 8-10 As can be seen from the data, the antenna exhibits good omnidirectional radiation characteristics within the omnidirectional radiation mode bandwidth, and its gain pattern... and The two cross-sections have good consistency and the gain is greater than 0 dBi.

[0051] In this embodiment, Figure 11 The voltage standing wave ratio (VSWR) curve for the directional radiation mode frequency band provided in this embodiment of the invention is shown below. Figure 11 It is known that the antenna operates within the directional radiation mode frequency band of 3.35GHz to 3.53GHz, with a voltage standing wave ratio (VSWR) of less than 2.0, resulting in good impedance characteristics within this band. The VSWR can be optimized by adjusting the size of the metal cladding layer of the fan-shaped patch 2 on the upper layer of the PCB substrate 3 and the position of the metallized via 7. Furthermore, the VSWR can also be optimized by adjusting the gap between the circular patch 1 and the fan-shaped patch 2.

[0052] In this embodiment, Figure 12 The circular polarization axial ratio curve of the directional radiation mode frequency band provided in the embodiments of the present invention is shown below. Figure 12 It can be seen that the antenna's axial ratio is less than 3.0dB within the frequency band of 3.35GHz to 3.53GHz, indicating that the antenna has good circular polarization characteristics within the directional radiation mode frequency band. The circular polarization axial ratio can be optimized by adjusting the size of the metal cladding layer of the fan-shaped patch 2 on the upper layer of the PCB substrate 3, the position of the metallized via 7, and the gap between the fan-shaped patch 2 and the circular patch 1.

[0053] In this embodiment, Figures 13-15 The gain pattern of the directional radiation mode frequency band provided in the embodiments of the present invention is from... Figures 13-15 As can be seen from the data, the antenna exhibits good directional radiation characteristics within the directional radiation mode frequency band, and its gain pattern... and The two cross-sections have good consistency and the gain is greater than 4.0 dBi.

[0054] The parts of this invention not described in detail are techniques that belong to those skilled in the art.

[0055] The above description is merely a preferred embodiment of the present invention, intended to further illustrate the invention, and not to limit it. Any simple substitutions made based on the content disclosed in the above text and drawings are within the scope of protection of this patent.

Claims

1. A low-profile multimode antenna, comprising a metallic ground layer, characterized in that, It includes an upper printed circuit board and a lower printed circuit board; the upper surface of the upper printed circuit board is provided with a central patch and an array of patches, the central patch is located at the center of the upper printed circuit board, and there are 4 array patches arranged in a circle with the central patch as the center. The metal ground layer is located between the upper and lower printed circuit boards. The lower surface of the lower printed circuit board is provided with a power supply network in the form of a 1-to-4 Wilkinson power divider. Each array patch has a first metallized via below it. One end of the first metallized via is connected to the array patch above it, and the other end passes through the metal ground layer and is connected to the corresponding branch end of the power supply network. The center patch has a second metallized via and multiple third metallized vias below it. One end of the second metallized via is connected to the center of the center patch, and the other end passes through the metal ground layer and is exposed on the lower printed circuit board. Multiple third metallized vias are evenly arranged with the second metallized via as the center. One end of the third metallized via is connected to the center patch, and the other end is connected to the upper surface of the metal ground layer. There is no contact between the array patches or between the array patches and the center patch; The central patch is circular, and the array patches are fan-shaped; the inner diameter of the array patches is larger than the diameter of the central patch.

2. The low-profile multimode antenna according to claim 1, characterized in that, Both the first and second metallized vias are not in contact with the metal formation.

3. A low-profile multimode antenna according to claim 1, characterized in that, It also includes two coaxial connectors, one of which has its inner center conductor connected to a second metallized through-hole and its outer conductor connected to a metal ground layer; the other coaxial connector has its inner center conductor connected to the main line of the power supply network and its outer conductor connected to a metal ground layer.

4. A low-profile multimode antenna according to claim 1, characterized in that, The first metallized through-hole, the second metallized through-hole, and the third metallized through-hole can all be equivalently replaced by metal pillars.

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