Low-profile miniaturized broadband antenna and array

Abstract

The invention discloses a low-profile miniaturized broadband antenna and array, the antenna mainly comprises a metal radiation patch, a dielectric layer with a high dielectric constant and a metal ground, a large rectangular patch in the metal radiation patch is directly excited by a feed signal to realize resonance in a low-frequency mode; and the relatively small rectangular patch couples energy into the relatively small rectangular patch by the relatively large rectangular patch through magnetic coupling, so that resonance in a high-frequency mode is realized. The metal radiation patch is provided with a metalized through hole which is connected with the metal ground, so that the antenna size is further reduced. According to the antenna array, a dielectric layer and a coplanar waveguide feed structure are additionally arranged on the basis of the antenna, and efficient excitation of the antenna array is achieved. According to the antenna and the array, miniaturization and wide bandwidth are both considered, and integrated design with miniaturized electronic equipment is facilitated. The antenna has the characteristics of low profile and miniaturization, so that the antenna also has the potential of general design.

Description

Technical Field

[0001] The present invention relates to a communication device, and in particular to a low-profile miniaturized broadband antenna and array. Background Art

[0002] Due to the development of wireless communication technology and the increasing demand for device integration, the problem of traditional antennas being too large restricts their application scenarios. Antennas need to develop towards miniaturization and low profile.

[0003] For positioning antennas of mobile electronic devices (mobile phones, tablets, drones, etc.), the line takes into account both miniaturization and wider bandwidth, which facilitates integrated design with miniaturized electronic devices.

[0004] In order to achieve broadband and miniaturized performance, existing patch antenna solutions often use multi-layer metal stacked structure design to achieve broadband radiation characteristics in a compact structure. However, this method usually has a complex antenna structure and a high antenna profile, which is not conducive to antenna integration and array deployment design in space-constrained scenarios. In addition, the multi-layer metal plate design leads to low antenna design flexibility, which makes it difficult to meet the requirements of antenna conformal compatibility design in complex scenarios. Summary of the invention

[0005] Purpose of the invention: In view of the above-mentioned prior art, a low-profile miniaturized broadband antenna and array is proposed, which takes into account both miniaturization and wider bandwidth.

[0006] Technical solution: A low-profile miniaturized broadband antenna, comprising a metal layer, a dielectric layer and a metal ground arranged in sequence from top to bottom; the metal layer serves as the radiator of the antenna, and is composed of a large rectangular patch and a small rectangular patch with a groove; the large rectangular patch is directly excited by a coaxial feeder probe penetrating from the metal ground to achieve resonance in a low-frequency mode; the small rectangular patch with a groove is arranged parallel to the large rectangular patch along the long side; a row of metallized through holes is provided on the same side of the short sides of the small rectangular patch and the large rectangular patch, for connecting the metal ground and the radiator; the small rectangular patch couples energy into it through magnetic coupling or ground current between patch structures to achieve resonance in a high-frequency mode.

[0007] Furthermore, the dielectric layer is made of a plate with a high dielectric constant.

[0008] A low-profile miniaturized broadband antenna array comprises, from top to bottom, a metal layer, a dielectric layer 1, a metal ground, a dielectric layer 2 and a coplanar waveguide feeding structure; the metal layer is provided with a plurality of radiator units; wherein each radiator unit is composed of a large rectangular patch and a small rectangular patch with a groove, and the small rectangular patch with the groove is arranged parallel to the large rectangular patch along the long side; a row of metallized through holes is arranged on the same side of the short sides of the small rectangular patch and the large rectangular patch, for connecting the metal ground and the radiator unit; the coplanar waveguide feeding structure comprises a plurality of coplanar waveguide transmission lines which are the same in number as the radiator units, and the ends of the coplanar waveguide transmission lines are respectively connected to the large rectangular patches of each radiator unit through metallized through holes.

[0009] Furthermore, a plurality of slots for isolating coupling currents between antenna units are provided on the metal ground.

[0010] Furthermore, the dielectric layer 1 and the dielectric layer 2 are made of plates with high dielectric constant.

[0011] Furthermore, the orientation of each radiator in the array is set according to the requirements of the antenna array radiation pattern and radiation polarization.

[0012] Furthermore, the slot groove is opened in a direction perpendicular to the current direction in the metal ground and is arranged in a middle position between adjacent antenna units.

[0013] Beneficial effects: The present invention proposes a low-profile miniaturized broadband antenna and array with a dual-patch structure based on high dielectric constant materials. The antenna takes into account both miniaturization and wide bandwidth, and is easy to integrate with miniaturized electronic devices. Since the antenna has the characteristics of low profile and miniaturization, it also takes into account the potential of common design.

[0014] The antenna array mainly includes a coplanar waveguide feeder, two layers of high dielectric constant dielectric layers, a metal ground and a metal radiation patch. The coplanar waveguide feeders are placed at one end, which is easy to realize integrated design with the transmission line, and provides high-efficiency matching for the three antenna units. The high dielectric constant dielectric layer will further reduce the cross-section of the structure. Gaps are provided on the metal ground to improve the isolation between each antenna unit and reduce the mutual coupling between antennas. The metal radiation patch is divided into two main bodies. The larger rectangular patch structure is connected to the coaxial feeder probe and is responsible for the resonance of the lower frequency band of the antenna matching; the smaller rectangular patch is a parasitic structure, and the larger rectangular patch couples energy into it through magnetic coupling, which is responsible for the matching of the higher frequency band in the antenna matching. The terminal of the above-mentioned radiation patch is provided with a metallized through-hole connected to the metal ground. This design can further reduce the size of the antenna.

[0015] In summary, the present invention proposes a low-profile, miniaturized broadband patch antenna unit and array structure. The antenna has a large bandwidth and the units of the antenna array have little mutual coupling. It is specifically used in the front end of the RF circuit of mobile electronic devices (mobile phones, tablets, drones, etc.) to achieve an integrated design of the antenna and the RF circuit, and has a good application scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the cross-sectional structure of a low-profile miniaturized broadband antenna;

[0017] Figure 2 It is a schematic diagram of the top structure of a low-profile miniaturized broadband antenna;

[0018] Figure 3 It is a schematic diagram of the bottom structure of a low-profile miniaturized broadband antenna;

[0019] Figure 4 It is a schematic diagram of the cross-sectional structure of a low-profile miniaturized broadband antenna array;

[0020] Figure 5 It is a schematic diagram of the top structure of a low-profile miniaturized broadband antenna array;

[0021] Figure 6 It is a schematic diagram of the bottom structure of a low-profile miniaturized broadband antenna array;

[0022] Figure 7 Schematic diagram of four arrangements of antenna units in a low-profile miniaturized broadband antenna array;

[0023] Figure 8 A schematic diagram of the coplanar waveguide feeding structure and dimensions of the antenna array;

[0024] Fig. 9 It is a schematic diagram of the metal ground structure and dimensions of the antenna array;

[0025] Fig.10 The schematic diagram of the structure and size of the top metal patch radiator of the antenna array;

[0026] Fig.11 A schematic diagram of the locations and sizes of the metallized through holes of the antenna radiation patch in the antenna array;

[0027] Fig.12 This is a simulation diagram of the matching of each port of the antenna;

[0028] Fig.13 This is a simulation diagram of the isolation of each antenna port;

[0029] Fig.14 It is the simulation diagram of antenna unit gain;

[0030] Fig.15This is a simulation diagram of the three-dimensional radiation pattern of the antenna. DETAILED DESCRIPTION

[0031] The present invention will be further explained below in conjunction with the accompanying drawings.

[0032] Embodiment 1:

[0033] like Figures 1 to 3 As shown, a low-profile miniaturized broadband antenna comprises, from top to bottom, a top metal layer 1, a dielectric layer 2, and a bottom metal ground 3.

[0034] The top metal layer 1 serves as the radiator of the antenna and is composed of a large rectangular patch 101 and a small rectangular patch 102 with a groove. The long side length of the large rectangular patch 101 is about one-fourth of the length of the center frequency band, and is directly excited by the coaxial feed line probe 5 that penetrates through the through hole 301 on the bottom metal ground 3. The large structural size realizes the resonance of the low-frequency mode, which is used for energy radiation and antenna matching, and forms resonant radiation in a lower frequency band.

[0035] The small rectangular patch 102 with a groove is arranged parallel to the large rectangular patch 101 along the long side, and the small rectangular patch 102 can be regarded as a parasitic structure. A row of metallized through holes 4 is arranged on the same side of the short side of the small rectangular patch 102 and the large rectangular patch 101, which is used to connect the bottom metal ground 3 and the radiator. Through the return ground treatment, part of the current distribution of the radiator can be introduced into the bottom metal ground 3, reducing the electrical length required for the resonant frequency, thereby reducing the size of the antenna to achieve a miniaturized design.

[0036] Due to the common ground design, the small rectangular patch 102 couples energy into it through magnetic coupling or ground current between the patch structures, forming resonant radiation in a higher frequency band, thereby achieving antenna matching and radiation in a high-frequency mode. The resonant modes of the large rectangular patch 101 and the small rectangular patch 102 jointly achieve the broadband radiation performance of the antenna. In addition, the frequencies of the two resonant modes can be adjusted by adjusting the gap width of the two patch structures, and the matching bandwidth of the antenna can be adjusted by adjusting the groove size of the small rectangular patch 102.

[0037] High dielectric constant plates are conducive to miniaturization of antenna size. It can be seen that the actual wavelength (electrical length) is inversely proportional to the relative dielectric constant, where λ r is the wavelength in the dielectric layer, λ0 is the wavelength in free space, ε r is the relative dielectric constant, μ r To realize the low profile and miniaturization of the antenna, in this embodiment, the dielectric layer 2 is made of FR4 material with a relative dielectric constant of 4.4.

[0038] The antenna is fed by coaxial feeding. In this embodiment, the inner core diameter of the probe 5 of the coaxial feed line is 0.3 mm, and it is connected to the large rectangular patch 101 through the dielectric layer 2 and the bottom metal ground 3. The input impedance of the antenna is changed by adjusting the feeding position on the large rectangular patch 101 to achieve wide-band matching of 50-Ω impedance.

[0039] Embodiment 2:

[0040] like Figures 4 to 6 As shown, a low-profile miniaturized broadband antenna array comprises, from top to bottom, a top metal layer 11, a dielectric layer 1 21, a metal ground 31, a dielectric layer 22, and a coplanar waveguide feeding structure 61. The antenna array of this embodiment is a 1×3 linear antenna array, and the top metal layer 11 is provided with three radiator units, which are designed the same as the radiator units of the antenna in Example 1. A row of metalized through holes 41 for connecting to the metal ground 31 is also provided on one side of each radiator unit.

[0041] In order to efficiently excite the antenna array, compared with the antenna structure of Example 1, a dielectric layer 22 and a coplanar waveguide feeding structure 61 are added to the bottom of the metal ground 31 of the antenna array. In this embodiment, the coplanar waveguide feeding structure 61 is designed with three coplanar waveguide transmission lines to respectively excite the three radiator units of the array. Specifically, three circular holes are opened at the corresponding positions of the metal ground 31, and the ends of each coplanar waveguide transmission line are connected to each radiator unit through the metallized through-holes 41 passing through the circular holes to complete the feeding of the final antenna array. The coplanar waveguide has a strong electromagnetic field binding characteristic, which can effectively avoid energy coupling between different ports in the feeding network.

[0042] In this antenna array, the antenna units are arranged closely to suit application scenarios with limited space. The arrangement of the antenna array can also be adjusted accordingly according to specific application requirements. Figure 7 As shown in (a) to (d), the directions of the radiators of the antenna units in the array can be combined arbitrarily to meet the requirements of different radiation patterns and radiation polarizations.

[0043] The three-unit array is arranged linearly. In the size-constrained scenario, the antenna units are closely spaced (less than half a wavelength), and the energy coupling between the antenna units is relatively strong. In order to reduce the energy coupling between closely arranged antennas, three slots are set on the metal floor 31. The arrangement of the slots in the metal floor depends on the current distribution of the metal floor. Generally, the slot direction is perpendicular to the current direction and is placed in the middle of the antenna unit to cut off the coupling current between the antenna units, improve the isolation between the antenna units, and reduce the mutual coupling between the antennas.

[0044] In this embodiment, the antenna unit structure has the advantages of small size, simple structure, low profile and single metal layer radiation. The wavelength of the central working frequency band 8GHz is λ0=37.5mm, and the length, width and height are 0.11λ0, 0.12λ0 and 0.04λ0 respectively. The three antenna unit array is placed in the 10mm×30mm position, which meets the requirements of compact miniaturization, planar structure, low profile and conformal design of drone terminals.

[0045] Figure 8 The detailed size information of the coplanar waveguide feeding structure is shown. The orange part is the metal trace, and the light blue part is the dielectric board FR4. The feeding structure is a 50Ω coplanar waveguide feed to achieve impedance matching with the external signal source. Metallized through holes are connected to the coplanar waveguide terminals to achieve the purpose of transmitting energy from the lower feeding network to the upper radiation patch. The specific parameter values ​​are defined by different digital numbers, namely: 001 = 0.37mm, 002 = 57mm, 003 = 10mm, 004 = 30mm, 005 = 14.5mm, 006 = 24mm, 007 = 5.1mm, 008 = 2mm.

[0046] Fig. 9 The metal ground structure between two FR4 dielectric layers and its detailed dimensions are shown. To improve the isolation of the antenna unit, three gaps are opened on the metal ground. At the same time, in order to better feed through the metallized through-hole, a circular hole is opened on the metal ground, the size of which is three times the diameter of the metallized through-hole. The specific parameter values ​​are defined with different digital numbers, namely: 009 = 4mm, 010 = 0.2mm, 011 = 5.5mm, 012 = 5mm, 013 = 0.3mm.

[0047] Fig.10 The structure and size of the metal radiation patch of the antenna array are shown. The orange part is the metal patch, and the light blue part is the dielectric substrate FR4 with a high dielectric constant. The distance between the two radiation patch branches is 021=0.1mm, and the energy of the smaller branch is magnetically coupled through the larger branch. The specific parameter values ​​are defined with different digital numbers, namely: 014=18.8mm, 015=3.3mm, 016=1.4mm, 017=4.3mm, 018=1mm, 019=1mm, 020=2.2mm, 021=0.1mm, 022=3.8mm. The antenna radiator of Example 1 can adopt the same design parameters.

[0048] Fig.11The location and size of the metallized through holes of the antenna radiation patch are shown. A row of metallized through holes is arranged on the left side of the radiation patch and connected to the metal ground. A single metallized through hole is arranged in the middle of the metal patch to feed the antenna. The specific parameter values ​​are defined with different digital numbers, namely: 023 = 0.2mm, 024 = 0.6mm, 025 = 0.6mm, 026 = 0.1mm.

[0049] Fig.12 The matching of each port of the antenna is shown, and it can be seen that the antenna achieves good matching between 7.5-8.5GHz. Fig.13 It is the isolation between antenna ports. It can be seen that within the antenna operating frequency band, the isolation of each port is almost less than -15dB. It can be seen that the antenna has good isolation, and the operations of each port are independent of each other with little mutual coupling. Fig.14 The maximum gain of the antenna unit working alone is shown. It can be seen that the average gain of the antenna is about 1dBi, which has good radiation characteristics. Fig.15 The three-dimensional radiation pattern of the antenna at the GHz frequency is displayed. It can be seen that the antenna beam is relatively stable and the radiation effect is good.

[0050] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A low-profile miniaturized broadband antenna, characterized in that: It includes a metal layer, a dielectric layer and a metal ground arranged in sequence from top to bottom; the metal layer serves as the radiator of the antenna, and is composed of a large rectangular patch and a small rectangular patch with a groove; the large rectangular patch is directly excited by a coaxial feeder probe penetrating from the metal ground to achieve resonance in a low-frequency mode; the small rectangular patch with the groove is arranged parallel to the large rectangular patch along the long side; a row of metallized through holes is provided on the same side of the short sides of the small rectangular patch and the large rectangular patch, which is used to connect the metal ground and the radiator; the small rectangular patch couples energy into it through magnetic coupling or ground current between patch structures to achieve resonance in a high-frequency mode.

2. The low-profile miniaturized broadband antenna according to claim 1, characterized in that: The dielectric layer is made of a plate with a high dielectric constant.

3. A low-profile miniaturized broadband antenna array, characterized in that: The invention comprises, from top to bottom, a metal layer, a dielectric layer 1, a metal ground, a dielectric layer 2 and a coplanar waveguide feeding structure; the metal layer is provided with a plurality of radiator units; wherein each radiator unit is composed of a large rectangular patch and a small rectangular patch with a groove, and the small rectangular patch with the groove is arranged parallel to the large rectangular patch along the long side; a row of metallized through holes is arranged on the same side of the short sides of the small rectangular patch and the large rectangular patch, for connecting the metal ground and the radiator unit; the coplanar waveguide feeding structure comprises a plurality of coplanar waveguide transmission lines which are the same in number as the radiator units, and the ends of the coplanar waveguide transmission lines are respectively connected to the large rectangular patches of each radiator unit through metallized through holes.

4. The low-profile miniaturized broadband antenna array according to claim 3, characterized in that: A plurality of slots for isolating coupling currents between antenna units are arranged on the metal ground.

5. A low-profile miniaturized broadband antenna array according to claim 3 or 4, characterized in that: The dielectric layer 1 and the dielectric layer 2 are made of plates with high dielectric constant.

6. A low-profile miniaturized broadband antenna array according to claim 3 or 4, characterized in that: The orientation of each radiator in the array is set according to the requirements of the antenna array radiation pattern and radiation polarization.

7. The low-profile miniaturized broadband antenna array according to claim 4, characterized in that: The slot groove is opened in a direction perpendicular to the current direction in the metal ground and is arranged in the middle of adjacent antenna units.

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