Microwave and millimeter wave large-frequency-ratio dual-frequency-band common-structure antenna

Abstract

The invention discloses a microwave and millimeter wave large-frequency-ratio dual-band common-structure antenna, a millimeter wave antenna and a microwave antenna are combined through a radiator structure multiplexing method, and an external material is metal. The millimeter wave antenna is in an array antenna form of a pure metal structure and comprises sub-radiation structures symmetrically distributed in the metal and a feed structure of the sub-radiation structures. The millimeter wave feed structure is provided with one input port and output ports with the same number as that of the radiation array elements, and equal-amplitude and equal-phase excitation is provided for all the radiation array elements. The microwave antenna is composed of a microwave radiation structure located in the middle of the millimeter wave array and a feed structure connected from the metal side face. The microwave feed structure avoids the millimeter wave array antenna, and mutual influence is avoided. According to the invention, while complex antenna structures of different frequency bands are integrated, good isolation is realized, the antenna has the advantages of large frequency ratio, wide working frequency band, high radiation efficiency and the like, the isolation between the two working frequency bands is good, and the antenna is a good antenna alternative scheme for a future communication system.

Description

Technical Field

[0001] This invention belongs to the field of electronics, and in particular relates to a microwave and millimeter-wave high frequency ratio dual-band common structure antenna. Background Technology

[0002] The development and use of new spectrum resources has been a constant throughout the development of wireless communication technology. Currently, 5G millimeter-wave bands and microwave bands, including the Sub-6 GHz band, are mostly networked independently. However, in reality, the two bands have distinct characteristics and complement each other. If the existing communication framework is broken through and the two bands are used rationally for collaborative networking, it is hoped that the advantages of both can be obtained.

[0003] As a key component in wireless communication systems, antennas often occupy most of the system's aperture space. Therefore, reducing antenna size or the number of antennas used in a system can effectively reduce the overall size of the communication system. For example, a single antenna can be used to cover multiple operating frequency bands simultaneously. From this perspective, integrated microwave and millimeter-wave antenna technology is expected to become one of the key technologies for miniaturizing dual-mode wireless communication systems in the B5G / 6G era. Currently, experts and scholars both domestically and internationally have conducted some research on dual-band integrated antenna technology. The reported technical solutions can be mainly summarized as single-unit multi-mode method, multi-body common aperture method, and multi-body structure multiplexing method.

[0004] Among them, the "multi-body structure multiplexing method" is an integrated design method for dual-band or even multi-band antennas by multiplexing radiator structures of different frequency bands. This technology has received considerable attention in recent years because it is relatively easy to achieve dual-band antennas or arrays with large frequency ratios. Its advantage lies in the fact that the frequency ratio of the two operating frequency bands of a dual-band antenna based on the multi-body structure multiplexing method can be large, and the radiators are not limited to single elements or arrays. However, the following problems still exist.

[0005] 1. The nesting of antenna structures at different frequencies makes the overall antenna structure more complex, and the coupling between different antennas will affect the performance of the common structure antenna. Therefore, the design of the common structure antenna is difficult.

[0006] 2. High-ratio common-structure antennas generally have low radiation efficiency. Traditional high-ratio common-structure antennas are mainly manufactured using printed circuit board technology, and the transmission efficiency of common-structure antennas needs further improvement. Furthermore, other antenna performance characteristics, such as bandwidth and isolation, also need further improvement.

[0007] 3. Due to the limitations of traditional antenna manufacturing technology and the nesting of different antenna structures, research on microwave and millimeter-wave integrated antenna technology based on the "multi-body structure multiplexing method" has been limited in terms of the flexibility of antenna structure multiplexing design, the selection of operating frequency bands, antenna performance, and functional diversity. Summary of the Invention

[0008] The purpose of this invention is to provide a high-ratio dual-band co-structure antenna for microwaves and millimeter waves, which effectively combines a millimeter-wave antenna and a microwave antenna. The two antennas operate with high isolation and can simultaneously achieve advantages such as large operating bandwidth and high efficiency in both the Sub-6 GHz and millimeter-wave bands. Through a multi-body structure multiplexing method, the high-ratio antenna structure is more compact and has a simpler shape.

[0009] To achieve the above objectives, the solution of the present invention is:

[0010] A microwave / millimeter-wave high-ratio dual-band common-structure antenna includes:

[0011] Metal casing;

[0012] The microwave radiating structure is located at the center inside the metal casing;

[0013] The millimeter-wave radiation structure consists of four sub-radiation structures symmetrically distributed around the microwave radiation structure, with a metal wall between the sub-radiation structures and the microwave radiation structure.

[0014] A millimeter-wave feeding structure is located below the millimeter-wave radiating structure and employs a waveguide power divider. The waveguide power divider has one input port and multiple output ports equal to the number of millimeter-wave radiating elements, used to provide equal amplitude and equal phase excitation to all millimeter-wave radiating elements.

[0015] A microwave feeding structure is inserted from the side of the metal casing. The feeding path of the microwave feeding structure avoids the millimeter-wave radiation structure and the millimeter-wave feeding structure, and feeds the microwave radiation structure.

[0016] Furthermore, the millimeter-wave feed structure adopts an air-filled rectangular waveguide structure, and achieves multi-channel equal amplitude and in-phase output by cascading multiple 1-to-2 power dividers.

[0017] Furthermore, the waveguide power divider includes:

[0018] A first-stage 1-to-2 power divider, the input port of which serves as the input port of the millimeter-wave feed structure;

[0019] Two second-stage 1-to-2 power dividers are connected to the two output ports of the first-stage 1-to-2 power divider, respectively.

[0020] Four third-stage 1-to-2 power dividers are provided, with their input terminals connected to the output ports of the two second-stage 1-to-2 power dividers, and the output ports of the third-stage 1-to-2 power dividers are connected to the millimeter-wave radiation array element.

[0021] Furthermore, the millimeter-wave radiation array element is a pyramidal horn, and each of the sub-radiation structures consists of two pyramidal horns. The two pyramidal horns in the same sub-radiation structure are staggered and have an offset in the long and short sides of their openings.

[0022] Furthermore, a bowtie-shaped waveguide structure is connected below each pyramidal horn radiating element.

[0023] Furthermore, the microwave radiation structure includes a radiation slit and two magnetic dipoles symmetrically distributed on both sides of it and directly connected to it, with the three arranged along the long side of the radiation slit.

[0024] Furthermore, the microwave feeding structure includes a bent metal probe and a coaxial cable; the bent metal probe is suspended in a cavity below the radiation slit, maintaining a distance from the cavity metal wall; the coaxial cable is inserted from a pre-reserved oblique cylindrical channel on the side of the metal shell, and its inner conductor is connected to the bent metal probe.

[0025] Furthermore, the shape of the outer surface of the metal casing is designed according to impedance matching and assembly requirements.

[0026] Furthermore, it also includes a metal floor disposed below the metal casing and a metal fence surrounding the microwave radiating structure to improve the radiation pattern of the antenna.

[0027] Furthermore, the waveguide power divider is provided with one or more of the following: matching stubs, steps, or ramp structures, to improve impedance matching.

[0028] By adopting the above scheme, the microwave and millimeter-wave radiation structure and feeding structure proposed in this invention are combined to form a microwave and millimeter-wave high-ratio dual-band common-structure antenna, which shares an internal metal wall structure. The microwave radiation structure uses radiation slots and magnetic dipoles, while the feeding structure uses bent metal probes and coaxial lines. The millimeter-wave radiation structure uses pyramidal horns as its radiating elements, and the feeding structure uses a waveguide power divider formed by air-filled waveguides. The antenna structure of this invention has the advantages of large operating bandwidth, good isolation, compact structure, and high radiation efficiency in both microwave and millimeter-wave bands, making it a good antenna candidate for future communication systems.

[0029] Beneficial effects:

[0030] 1. This invention places the microwave radiating structure at the center inside a metal casing, while decomposing the millimeter-wave radiating structure into four sub-radiating structures symmetrically distributed around the microwave structure and physically isolated by a shared metal wall. The millimeter-wave feed network is located directly below the microwave structure, while the microwave feed is inserted obliquely from the side of the metal casing. This layout maximizes the use of three-dimensional space, achieving extremely high structural compactness. Simultaneously, physical isolation and spatial avoidance of feed paths minimize electromagnetic coupling between the two frequency band antennas, thereby achieving excellent port isolation (better than 35dB) and fundamentally solving the problem of severe internal interference in high-ratio, common-aperture antennas.

[0031] 2. In this invention, the millimeter-wave feeding structure adopts an air-filled rectangular waveguide, and a lossless feeding network is constructed by cascading the first, second and third stage power dividers to provide equal amplitude and in-phase excitation for all pyramidal horn radiating elements.

[0032] The waveguide structure itself has extremely low loss. Combined with an optimized power divider design (which can introduce matching stubs, steps, etc.), it ensures high radiation efficiency and good impedance matching of the feed network, overcoming the shortcomings of traditional PCB feed networks with high loss in the high-frequency band and ensuring the overall performance of the millimeter-wave band.

[0033] 3. In this invention, each sub-radiating structure consists of two pyramidal horns, and these two horns have a specific staggered offset in the long and short directions of their openings. A bowtie-shaped waveguide structure can also be connected below each horn to guide the beam.

[0034] This non-uniform array arrangement can effectively suppress the grating lobes of the millimeter-wave array, optimize the radiation pattern, improve the main lobe width, and reduce the side lobe level, thereby meeting the requirements of practical communication systems for coverage quality and anti-interference capability.

[0035] 4. In this invention, the microwave radiation structure consists of a radiation slit and magnetic dipoles directly connected to both sides, forming a magnetoelectric composite model. Power is supplied by a bent metal probe suspended in a cavity beneath the radiation slit, and coupled and excited via a coaxial line inserted obliquely from the side.

[0036] This composite radiation model easily achieves broadband characteristics in the microwave band within a limited space. The unique probe coupling and side-fed design perfectly avoids the underlying millimeter-wave structure, achieving efficient feeding while minimizing the impact on the millimeter-wave system.

[0037] 5. In addition to the basic structure, the present invention may optionally add a metal floor under the metal shell and add a metal fence around the microwave radiation structure.

[0038] These additional structures further improve the symmetry and front-to-back ratio of the microwave band radiation pattern, enhance the overall gain and stability of the antenna, and make its performance more suitable for the needs of practical application scenarios such as base stations.

[0039] 6. The entire antenna of this invention (including the radiator, feed circuit, and shell) is a pure metal integrated structure with no built-in dielectric or easily damaged solder joints.

[0040] This design enables the antenna to have extremely high power capacity and environmental reliability. At the same time, its structure is very suitable for one-time molding using CNC cutting or metal 3D printing (additive manufacturing) technology, which has outstanding advantages such as high machining accuracy, simple assembly, and ease of mass production, making it of great engineering application value. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the microwave / millimeter-wave high frequency ratio dual-band co-structure antenna scheme provided by the present invention.

[0042] Figure 2 This is a schematic diagram of the structure of the microwave / millimeter-wave high frequency ratio dual-band common structure antenna provided by the present invention.

[0043] Figure 3 This is a schematic diagram of the overall structure of the millimeter-wave pyramidal horn array and the internal metal power supply structure provided by the present invention.

[0044] Figure 4 This is a schematic diagram of a power divider structure with two equal amplitude and equal phase outputs formed by an air-filled waveguide, provided by the present invention.

[0045] Figure 5 This is a schematic diagram of a power divider structure with two equal amplitude and equal phase outputs formed by an air-filled waveguide, provided by the present invention.

[0046] Figure 6 This is a partial cross-sectional three-dimensional structural schematic diagram of the microwave / millimeter-wave high frequency ratio dual-band common structure antenna provided by the present invention.

[0047] Figure 7 A schematic diagram of the structure of a microwave / millimeter-wave high frequency ratio dual-band co-structure antenna with added metal floor and fence provided by the present invention.

[0048] Figure 8 This is a schematic diagram of the S-parameters and gain simulation curves of a microwave / millimeter-wave high-ratio dual-band co-structure antenna with added metal floor and fence in the millimeter-wave band.

[0049] Figure 9 This is a schematic diagram of the isolation curve of a microwave / millimeter-wave high frequency ratio dual-band co-structure antenna with added metal floor and fence in the millimeter-wave band.

[0050] Figure 10 This is a schematic diagram of the S-parameters and gain simulation curves of a microwave / millimeter-wave high-ratio dual-band co-structure antenna with added metal floor and fence in the microwave band.

[0051] Figure 11 This is a schematic diagram of the isolation curve of a microwave / millimeter-wave high frequency ratio dual-band co-structure antenna with added metal floor and fence in the microwave band.

[0052] Figure 12 The results are simulations of the radiation pattern of a microwave / millimeter-wave high-ratio dual-band co-structure antenna with added metal floor and fence in the millimeter-wave band.

[0053] Figure 13 The results are simulations of the radiation pattern of a microwave / millimeter-wave high-ratio dual-band co-structure antenna with added metal floor and fence in the microwave band. Detailed Implementation

[0054] The technical solution and beneficial effects of the present invention will be described in detail below with reference to the accompanying drawings.

[0055] Reference Figure 1 This invention provides a microwave / millimeter-wave high-ratio dual-band co-structure antenna, comprising a microwave radiating structure 1, a microwave feeding structure 2, millimeter-wave sub-radiating structures 3 and 4, and an external metal 5. The microwave radiating structure 1 is located in the center of the antenna. The millimeter-wave sub-radiating structures 3 are distributed around the microwave radiating structure, with four identical sub-radiating structures located in four sub-regions on the upper surface of the metal rectangle, spaced apart from the metal edge. Each sub-radiating structure can consist of multiple radiating elements. The feeding structure 4 of the millimeter-wave array antenna is located directly below the array sub-radiating structures. To ensure equal amplitude and phase excitation for the radiating elements, the feeding structure employs a power divider with equal amplitude and phase output, having one input port and an output port equal to the number of radiating elements. The microwave feeding structure 2 is inserted from the side of the metal, feeding the microwave radiating structure without disrupting the millimeter-wave radiating structure and the feeding structure.

[0056] Reference Figure 2 The uppermost part of the microwave / millimeter-wave high-frequency-ratio dual-band co-structure antenna is its radiating structure, which includes a radiating slot 6 at the center of the metal, magnetic dipoles 7 connected to the radiating slot on both sides, and a pyramidal horn array 8 distributed around the radiating slot. The radiating slot and magnetic dipoles are designed to operate in the microwave band, while the pyramidal horn array is designed to operate in the millimeter-wave band. The structure of the external metal 5 can be adjusted according to impedance bandwidth, antenna installation requirements, and other factors.

[0057] Reference Figure 3This system provides a millimeter-wave radiation and feeding structure within a metal core, including a pyramidal horn array 8 and a millimeter-wave feeding structure composed of air-filled waveguides. From top to bottom, the millimeter-wave structure consists of the pyramidal horn array 8, a bow-tie waveguide structure 9, a 1-to-2 power divider 10, and a 1-to-4 power divider 11. The pyramidal horn array 8 is divided into four sub-radiating structures by the millimeter-wave feeding structure 4. Each sub-radiating structure corresponds to the output of a third-stage 1-to-2 power divider 10, and adjacent sub-radiating structures are symmetrical about their axes. The radiating elements are pyramidal horns, and each sub-radiating structure contains a pair of staggered pyramidal horns, with the long side of their opening aligned with the long side of the radiating slot. The pyramidal horns are offset in different directions to improve the main-to-side lobe ratio of the entire antenna's radiation pattern in the millimeter-wave band; the offset can be adjusted according to the required main-to-side lobe ratio. A bow-tie waveguide structure can be connected below each pyramidal horn radiating element to adjust the propagation direction of the electromagnetic waves within it.

[0058] Reference Figure 4 and Figure 5 The millimeter-wave feed structure employs a power divider formed by an air-filled waveguide, enabling eight equal-amplitude and equal-phase outputs. Matching stubs, steps, and ramps are added to improve impedance matching. A 1-to-2 power divider 10 provides equal-amplitude and equal-phase excitation to two staggered pyramidal horns in the sub-radiating structure. Its input port is connected to the output of power divider 11, and its output port is connected to the bow-tie waveguide structure 9. Similarly, a 1-to-4 power divider 11 is composed of two 1-to-2 power dividers of different sizes, providing equal-amplitude and equal-phase outputs. Its external input port is located at the center of the lower surface of the metal.

[0059] Reference Figure 6 The microwave radiating structure consists of radiating slots arranged along the central axis of a metal element, symmetrically distributed magnetic dipoles on both sides, a bent metal probe 12 for feeding, and a coaxial line 13. The magnetic dipoles are formed by currents on the two bent metal surfaces outside the radiating slots, and the magnetic dipoles on both sides are connected to the radiating slots. A slanted cylindrical channel to accommodate the coaxial line is reserved in the middle of the outer side of the metal element. The bent metal probe is suspended inside a polygonal cavity below the radiating slot, maintaining a certain distance from the cavity sidewalls. The coaxial line 13 is inserted into the antenna through the reserved slanted cylindrical channel, and its inner conductor is connected to the bent metal probe 12.

[0060] Reference Figure 7 A metal ground plane 14 and a fence structure 15 can be added to the outside of the microwave and millimeter wave high frequency ratio dual-band co-structure antenna to improve the radiation pattern of the microwave radiation structure.

[0061] To verify the authenticity and reliability of the microwave / millimeter-wave high-ratio dual-band co-structure antenna provided by this invention, an example of a microwave / millimeter-wave high-ratio dual-band co-structure antenna operating in the sub-6GHz and millimeter-wave bands was designed according to the technical solution provided by this invention. In the designed example, the centers of the two staggered pyramidal horns are offset by 12mm in the short side direction and 12.3mm in the long side direction of their openings. The radiating slot has a long side dimension of 23.2mm and a short side dimension of 14mm. The magnetic dipoles on both sides have a 1mm wide opening on the upper surface, connected to a 50Ω coaxial line via a bent metal probe. The metal ground plane has a length of 92.5mm, a width of 66mm, and a fence height of 22mm. This example antenna meets the processing requirements of additive manufacturing and can be rapidly processed using 3D metal printing technology.

[0062] Figures 8 to 13 The relevant performance simulation parameters of the example antenna are given. Considering the -10dB impedance bandwidth and 3dB gain fluctuation, the antenna exhibits a wide impedance bandwidth in both microwave and millimeter-wave bands. While maintaining a compact structure, good isolation is achieved at both ports in both frequency bands through a rationally designed structural multiplexing method for the two bands.

[0063] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A microwave / millimeter-wave high-frequency ratio dual-band common-structure antenna, characterized in that, include: Metal casing (5); The microwave radiation structure (1) is located at the center of the interior of the metal shell; The millimeter-wave radiation structure is composed of four sub-radiation structures (3) symmetrically distributed around the microwave radiation structure, and a metal wall is provided between the sub-radiation structures and the microwave radiation structure. The millimeter-wave feeding structure (4) is located below the millimeter-wave radiation structure and adopts a waveguide power divider. The waveguide power divider has one input port and multiple output ports equal to the number of millimeter-wave radiation array elements, which are used to provide equal amplitude and equal phase excitation to all millimeter-wave radiation array elements. A microwave feeding structure (2) is inserted from the side of the metal shell. The feeding path of the microwave feeding structure avoids the millimeter-wave radiation structure and the millimeter-wave feeding structure, and feeds the microwave radiation structure.

2. The antenna according to claim 1, characterized in that, The millimeter-wave feed structure adopts an air-filled rectangular waveguide structure and achieves multi-channel equal amplitude and in-phase output through multiple cascaded one-to-two power dividers.

3. The antenna according to claim 2, characterized in that, The waveguide power divider includes: A first-stage 1-to-2 power divider, the input port of which serves as the input port of the millimeter-wave feed structure; Two second-stage 1-to-2 power dividers are connected to the two output ports of the first-stage 1-to-2 power divider, respectively. Four third-stage 1-to-2 power dividers are provided, with their input terminals connected to the output ports of the two second-stage 1-to-2 power dividers, and the output ports of the third-stage 1-to-2 power dividers are connected to the millimeter-wave radiation array element.

4. The antenna according to claim 1, characterized in that, The millimeter-wave radiation array element is a pyramidal horn (8), and each of the sub-radiation structures (3) consists of two pyramidal horns. The two pyramidal horns in the same sub-radiation structure are staggered and have an offset in the long and short sides of their openings.

5. The antenna according to claim 4, characterized in that, Each pyramidal horn radiating element is connected to a bowtie-shaped waveguide structure (9) below it.

6. The antenna according to claim 1, characterized in that, The microwave radiation structure includes a radiation slit (6) and two magnetic dipoles (7) symmetrically distributed on both sides of it and directly connected to it, with the three arranged along the long side of the radiation slit.

7. The antenna according to claim 1, characterized in that, The microwave feeding structure includes a bent metal probe (12) and a coaxial line (13); the bent metal probe is suspended in the cavity below the radiation slit (6) and maintains a distance from the metal wall of the cavity; the coaxial line (13) is inserted from the oblique cylindrical channel reserved on the side of the metal shell, and its inner conductor is connected to the bent metal probe (12).

8. The antenna according to claim 1, characterized in that, The shape of the outer surface of the metal shell (5) is designed according to impedance matching and assembly requirements.

9. The antenna according to claim 1, characterized in that, It also includes a metal floor (14) disposed below the metal casing (5) and a metal fence (15) surrounding the microwave radiating structure (1) for improving the radiation pattern of the antenna.

10. The antenna according to any one of claims 1-9, characterized in that, The waveguide power divider is equipped with one or more of the following structures: matching stubs, steps, or ramps, to improve impedance matching.

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