Dual-polarized electrically small antenna unit and MIMO array thereof

Abstract

In the antenna unit, a dielectric layer comprises an upper microwave dielectric substrate, an upper bonding medium, a middle microwave dielectric substrate, a lower bonding medium and a lower substrate layer which are sequentially bonded from top to bottom, and a metal copper layer comprises a radiation patch layer, an antenna grounding layer and a connecting layer; the metal via hole comprises a metal feed through hole and a metal short circuit buried hole; the metal feed through hole penetrates through the dielectric layer, namely penetrates from the upper microwave dielectric substrate to the lower substrate layer; and a plurality of metal short-circuit buried holes are provided and penetrate through the middle-layer microwave dielectric substrate. The dual-polarized electrically small antenna unit and the MIMO array thereof have the characteristics of high efficiency, high gain, wide beam and the like, and are suitable for application requirements of 5G FR3 frequency band and future 6G wireless network terminal communication.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a dual-polarized electrically small antenna unit and a MIMO array thereof. Background Art

[0002] As 5G networks continue to evolve, the extensive utilization of the FR1 (0.41-7.125 GHz) and FR2 (24.25-52.6 GHz) frequency bands forms the core foundation of existing wireless communications networks. To meet the technological demands of the 5G-Advanced and 6G eras, the industry is accelerating the standardization of the third spectrum resource (FR3) covering 7-15 GHz to achieve multi-dimensional collaborative networking across all frequency bands.

[0003] The rapid development of wireless communication systems has placed stringent demands on antenna design, including miniaturization, multifunctional integration, and high performance in multiple-input, multiple-output (MIMO) systems. Electrically small antennas (ESAs) provide an effective technical path for miniaturizing MIMO antennas. Their physical dimensions must satisfy the electrical dimension requirement ka<1. Based on the Chu-Harrington theory and McLean's correction to the Q value of electrically small antennas, the Q value of an electrically small linearly polarized antenna can be expressed as: Q=1 / (ka)+1 / (ka) 3 Where k is the wave number and a is the radius of the smallest sphere that encloses the antenna; When ka is very small, the Q value is related to (ka) 3 The actual operating bandwidth is limited by the radiation efficiency and Q value. This determines that a compromise between bandwidth and radiation efficiency must be made during design.

[0004] There are many ways to design and implement electrically small antennas, but there are still some design difficulties in applying them to the high-frequency spectrum of next-generation mobile communications. For example: 1. The design of dual-polarized electrically small antennas is complex. In previous research, due to antenna size limitations, most designed electrically small antennas were single-polarized antennas, limiting their application in MIMO systems. Designing dual-polarized electrically small antennas requires considering impedance matching, polarization isolation, and physical layout.

[0005] 2. Miniaturization leads to increased near-field coupling in MIMO arrays and increased cross-coupling between elements. Decoupling structures are needed to reduce inter-element coupling, thereby improving array gain and suppressing cross-polarization at very small element spacing.

[0006] 3. At high frequencies, conventional high-dielectric-constant substrates introduce additional losses, reducing the antenna's radiation efficiency and gain. The Q value of electrically small antennas is extremely high, requiring consideration of both radiation efficiency and antenna bandwidth design. Summary of the Invention

[0007] Technical purpose: In response to the defects in the existing technology, the present invention discloses a dual-polarized electrically small antenna unit and its MIMO array, which has high efficiency, high gain, wide beam, low profile, dual-polarized electrically small antenna and its MIMO array, and has the advantages of low processing cost, suitability for mass production, and easy connection with external integrated circuits and other microwave radio frequency modules.

[0008] Technical solution: In order to achieve the above technical objectives, the present invention adopts the following technical solution.

[0009] A dual-polarized electrical small antenna unit, comprising: a dielectric layer, a metal copper layer bonded to the dielectric layer, and a metal via penetrating the dielectric layer; The dielectric layer includes an upper microwave dielectric substrate, an upper bonding dielectric, a middle microwave dielectric substrate and a lower base plate layer, which are bonded together in sequence from top to bottom. The metal copper layer includes the radiation patch layer, antenna ground layer and connection layer; A radiation patch layer is provided between the upper bonding dielectric layer and the middle microwave dielectric substrate, and an antenna ground layer is provided between the middle microwave dielectric substrate and the lower base plate layer; a connection layer is provided at the bottom of the lower base plate layer; a first radiation patch is provided in the radiation patch layer, and the first radiation patch is penetrated by a metal feed through hole; Metal vias include metal feed through holes and metal short-circuit buried holes; The metal feed vias include a first metal feed via and a second metal feed via. The metal feed vias penetrate the dielectric layer, that is, from the upper microwave dielectric substrate to the lower base plate layer, to connect the radiation patch layer and the connection layer; there are several metal short-circuit buried vias, which penetrate the middle microwave dielectric substrate and are connected to the antenna ground layer.

[0010] A MIMO array of dual-polarized electrically small antenna units includes two identical dual-polarized electrically small antenna units, wherein the dual-polarized electrically small antenna units are one of the dual-polarized electrically small antenna units described above, the two dual-polarized electrically small antenna units are mirror-symmetrical in left and right directions, and share a common dielectric layer; the radiation patches in the two dual-polarized electrically small antenna units are mirror-symmetrical in center about an intermediate microwave dielectric substrate; microstrip feed lines with co-polarized ports apply excitation with equal amplitudes and opposite phases; two comb-shaped defective gaps are opened on the antenna ground layer between adjacent dual-polarized electrically small antenna units, and the two comb-shaped defective gaps are mirror-symmetrical.

[0011] A dual-polarized electrical small antenna unit, comprising: a dielectric layer, a metal copper layer bonded to the dielectric layer, and a metal via penetrating the dielectric layer; The dielectric layer includes an upper microwave dielectric substrate, an upper bonding dielectric, a middle microwave dielectric substrate and a lower base plate layer, which are bonded together in sequence from top to bottom. The metal copper layer includes the radiation patch layer, antenna ground layer and connection layer; A radiation patch layer is provided between the upper bonding dielectric layer and the middle microwave dielectric substrate, and an antenna ground layer is provided between the middle microwave dielectric substrate and the lower base plate layer; a connection layer is provided at the bottom of the lower base plate layer; a first radiation patch is provided in the radiation patch layer, and the first radiation patch is penetrated by a metal feed through hole; Metal vias include metal feed through holes and metal short-circuit buried holes; The metal feed vias include a first metal feed via and a second metal feed via. The metal feed vias penetrate the dielectric layer, that is, from the upper microwave dielectric substrate to the lower base plate layer, to connect the radiation patch layer and the connection layer. There are a plurality of metal short-circuit buried vias, which penetrate the middle microwave dielectric substrate and connect to the antenna ground layer. The lower substrate layer includes a first antenna unit bottom plate; the connection layer includes a first solder ball layer and a first stepped impedance transformation line; the first solder ball layer is arranged between the middle microwave dielectric substrate and the first antenna unit bottom plate; and the first stepped impedance transformation line is arranged at the bottom of the first antenna unit bottom plate.

[0012] A MIMO array of dual-polarized electrically small antenna units includes two identical dual-polarized electrically small antenna units, wherein the dual-polarized electrically small antenna units are one of the dual-polarized electrically small antenna units described above, the two dual-polarized electrically small antenna units are mirror-symmetrical in left and right directions, and share a common dielectric layer; the radiation patches in the two dual-polarized electrically small antenna units are mirror-symmetrical in center about an intermediate microwave dielectric substrate; and microstrip feed lines at the same polarization ports apply excitations with equal amplitudes and opposite phases.

[0013] Beneficial effects: The dual-polarized electrically small antenna unit and its MIMO array proposed in this invention have the characteristics of compact size (electrically small) and dual-polarized radiation. The implementation principle is mainly divided into three parts: (1) The present invention uses a microwave dielectric substrate loaded on a radiation patch as one of the methods for miniaturizing the antenna. The loaded microwave dielectric substrate is equivalent to a series resistor and a parallel capacitor in the antenna circuit, resulting in a decrease in the resonant frequency and a certain dielectric loss. (2) The present invention adds a circle of metal short-circuit buried vias around the radiating patch, forming gap capacitance between adjacent metal short-circuit buried vias. Furthermore, the proximity of the metal short-circuit buried vias to the radiating patch creates a capacitance effect, which is equivalent to a parallel capacitor, further reducing the size of the antenna. The metal short-circuit buried vias are connected to the antenna ground layer at a height equal to that of the middle microwave dielectric substrate, introducing an inductance effect and achieving impedance matching. (3) The dual-polarized electrically small antenna unit proposed in the present invention operates in the TE10 mode of a patch antenna. The modes excited by the two polarization ports are orthogonal to each other, achieving good polarization isolation between the two ports and suppressing cross polarization. (4) The dual-polarized electrically small antenna unit and its MIMO array proposed in the present invention have the advantages of wide beam, high efficiency, low processing cost, and easy connection with external integrated circuits and other microwave radio frequency modules. They are suitable for 5G and future 6G satellite communications and mobile terminal applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic structural diagram of a dual-polarized electrically small antenna unit according to embodiment 1 of the present invention; Figure 2 This is a front view of a dual-polarized electric small antenna unit according to embodiment 1 of the present invention; Figure 3 This is a schematic structural diagram of a radiation patch layer in a dual-polarized electrically small antenna unit according to embodiment 1 of the present invention; Figure 4 This is a schematic structural diagram of an antenna ground layer in a dual-polarized electrically small antenna unit according to embodiment 1 of the present invention; Figure 5 This is a structural diagram of a feeding ground layer in a dual-polarized electrically small antenna unit according to embodiment 1 of the present invention; Figure 6 This is a schematic structural diagram of a microstrip line layer in a dual-polarized electrically small antenna unit according to embodiment 1 of the present invention; Figure 7 This is a structural diagram of a MIMO array of dual-polarized electrically small antenna units according to embodiment 1 of the present invention; Figure 8 This is a schematic structural diagram of a radiation patch layer in a MIMO array of a dual-polarized electrically small antenna unit according to embodiment 1 of the present invention; Figure 9 This is a schematic structural diagram of an antenna ground layer in a MIMO array of dual-polarized electrically small antenna units according to embodiment 1 of the present invention; Figure 10 This is a structural diagram of a feeding ground layer in a MIMO array of dual-polarized electrically small antenna units according to embodiment 1 of the present invention; Figure 11This is a schematic structural diagram of a microstrip line layer in a MIMO array of a dual-polarized electrically small antenna unit according to embodiment 1 of the present invention; Figure 12 This is a simulation diagram of S parameters and gain of a dual-polarized electrically small antenna unit according to Example 1 of the present invention; Figure 13 This is a simulation diagram of the radiation efficiency of a dual-polarized electrically small antenna unit according to Example 1 of the present invention; Figure 14 This is a simulation diagram of the directional pattern of a dual-polarized electrically small antenna unit in the plane of Phi=-45° and phi=45° at 13 GHz according to Example 1 of the present invention; Figure 15 The S parameters and gain simulation of a MIMO array of dual-polarized electrically small antenna units in embodiment 1 of the present invention are as follows: Figure 1 ; Figure 16 The S parameters and gain simulation of a MIMO array of dual-polarized electrically small antenna units in embodiment 1 of the present invention are as follows: Figure 2 ; Figure 17 This is a simulation diagram of the radiation efficiency of a MIMO array of dual-polarized electrically small antenna units according to Example 1 of the present invention; Figure 18 This is a simulation diagram of the directional pattern of a MIMO array of dual-polarized electrically small antenna units at 13 GHz in the planes of Phi=-45° and phi=45° according to Example 1 of the present invention; Figure 19 This is a structural diagram of a dual-polarized electrically small antenna unit according to embodiment 2 of the present invention; Figure 20 This is a structural diagram of a MIMO array of dual-polarized electrically small antenna units according to embodiment 2 of the present invention; Figure 21 This is a simulation diagram of S parameters and gain of a dual-polarized electrically small antenna unit according to embodiment 2 of the present invention; Figure 22 This is a simulation diagram of the radiation efficiency of a dual-polarized electrically small antenna unit according to Example 2 of the present invention; Figure 23 This is a simulation diagram of the directional pattern of a dual-polarized electrically small antenna unit in the plane of Phi=-45° and phi=45° at 13 GHz according to Example 2 of the present invention; Figure 24 The S parameters and gain simulation of a MIMO array of dual-polarized electrically small antenna units according to embodiment 2 of the present invention are as follows: Figure 1 ; Figure 25 The S parameters and gain simulation of a MIMO array of dual-polarized electrically small antenna units according to embodiment 2 of the present invention are as follows: Figure 2 ; Figure 26 This is a simulation diagram of the radiation efficiency of a MIMO array of dual-polarized electrically small antenna units according to Example 2 of the present invention; Figure 27 This is a simulation diagram of the directional pattern of a MIMO array of dual-polarized electrically small antenna units at 13 GHz in the planes of Phi=-45° and phi=45° according to Example 2 of the present invention; Among them, 1-1 is the upper microwave dielectric substrate, 1-2 is the middle microwave dielectric substrate, 1-3 is the lower microwave dielectric substrate, 2-1 is the upper bonding medium, 2-2 is the lower bonding medium, 3-1 is the radiation patch layer, 3-2 is the antenna ground layer, 3-3 is the feed ground layer, 3-4 is the microstrip line layer; 4-1 is the first metal feeding via, 4-2 is the second metal feeding via, 4-3 is the third metal feeding via, 4-4 is the fourth metal feeding via, 5-1 is the metal short-circuit buried hole; 6-1 is the first radiation patch; 6-2 is the second radiation patch; 7-1 is the first coaxial outer conductor hole one, 7-2 is the second coaxial outer conductor hole one, 7-3 is the third coaxial outer conductor hole one, 7-4 is the fourth coaxial outer conductor hole one, 8-1 is the first coaxial outer conductor hole one The outer coaxial conductor hole is the second, 8-2 is the second coaxial outer conductor hole; 8-3 is the third coaxial outer conductor hole; 8-4 is the fourth coaxial outer conductor hole; 9-1 is the first microstrip feed line; 9-2 is the second microstrip feed line; 9-3 is the third microstrip feed line; 9-4 is the fourth microstrip feed line; 10-1 is a comb-shaped defect gap; 11-1 is the first antenna unit base plate; 11-2 is the second antenna unit base plate; 13-1 is the first solder ball layer; 13-2 is the second solder ball layer; 14-1 is the first stepped impedance transformation line; 14-2 is the second stepped impedance transformation line; 15-1 is the first local antenna unit; 15-2 is the second local antenna unit; 16-1 is the first BGA base plate connection hole; 16-2 is the second BGA base plate connection hole. DETAILED DESCRIPTION

[0015] In order to help those skilled in the art better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0016] A dual-polarized electric small antenna unit of the present invention comprises: a dielectric layer, a metal copper layer bonded to the dielectric layer, and a metal via penetrating the dielectric layer; The dielectric layer includes an upper microwave dielectric substrate 1-1, an upper bonding medium 2-1, a middle microwave dielectric substrate 1-2 and a lower base plate layer, which are bonded together in sequence from top to bottom. The metal copper layer includes a radiation patch layer 3-1, an antenna ground layer 3-2 and a connection layer; A radiation patch layer 3-1 is provided between the upper bonding medium 2-1 and the middle microwave dielectric substrate 1-2, and an antenna grounding layer 3-2 is provided between the middle microwave dielectric substrate 1-2 and the lower substrate layer; a connection layer is provided at the bottom of the lower substrate layer; The metal vias include metal feed through holes and metal short-circuit buried holes 5-1; The metal feed vias include a first metal feed via 4-1 and a second metal feed via 4-2. These metal feed vias penetrate the dielectric layer, from the upper microwave dielectric substrate 1-1 to the lower baseboard layer, connecting the radiating patch layer 3-1 to the connection layer. Several metal short-circuit buried vias 5-1 are provided. These metal short-circuit buried vias 5-1 penetrate the middle microwave dielectric substrate 1-2 and connect to the antenna ground layer 3-2. The metal short-circuit buried vias 5-1 are inscribed within the edges of the middle microwave dielectric substrate 1-2 and surround the antenna to form a square frame. The spacing between the metal short-circuit buried vias 5-1 is twice their diameter.

[0017] The radiating patch layer 3-1 is located between the middle microwave dielectric substrate 1-2 and the upper adhesive layer 2-1. Through the PCB lamination process, the radiating patch layer 3-1 is embedded in the upper adhesive layer 2-1. A first radiating patch 6-1 is provided within the radiating patch layer 3-1, penetrated by a metal feed hole. The first radiating patch 6-1 is a square patch with four chamfered corners and is positioned at a 45-degree angle relative to the middle microwave dielectric substrate 1-2. The metal feed hole is located in the upper half of the first radiating patch 6-1, on a diagonal line of the plane of the middle microwave dielectric substrate 1-2. The metal feed holes are symmetrical about the diagonal line of the first radiating patch 6-1 and are equidistant from both sides of the upper half of the first radiating patch 6-1. Adjusting the size and angle of the first radiating patch 6-1 can change the operating frequency of the antenna. Increasing the size or decreasing the angle shifts the operating frequency toward lower frequencies; decreasing the size or increasing the angle shifts the operating frequency toward higher frequencies.

[0018] The outer dimensions of the antenna ground layer 3-2 are equal to those of the middle-layer microwave dielectric substrate 1-2.

[0019] The antenna ground layer 3-2 is provided with coaxial outer conductor holes of the same size. The coaxial outer conductor holes include a first coaxial outer conductor hole 7-1 and a second coaxial outer conductor hole 7-2. The coaxial outer conductor holes correspond to the metal feed through holes and have the same axis as the metal feed through holes, that is, their orthographic projection positions are the same. The coaxial outer conductor holes are larger than the metal feed through holes.

[0020] The present invention also discloses a MIMO array of dual-polarized electrically small antennas, comprising two identical dual-polarized electrically small antenna units, the two dual-polarized electrically small antenna units being mirror-symmetrical in left and right directions and sharing a common dielectric layer; the radiation patches in the two dual-polarized electrically small antenna units being mirror-symmetrical in center about an intermediate microwave dielectric substrate 1-2; and microstrip feed lines of the same polarization ports applying excitations of equal amplitude and opposite phase.

[0021] Specifically, the first radiation patch 6-1 in one dual-polarized electric small antenna unit and the second radiation patch 6-2 in the other dual-polarized electric small antenna unit are mirror-symmetrical about the center of the middle microwave dielectric substrate 1-2 of the MIMO array.

[0022] The first metal feeding through hole 4-1 and the second metal feeding through hole 4-2 of one dual-polarized electric small antenna unit, and the third metal feeding through hole 4-3 and the fourth metal feeding through hole 4-4 of another dual-polarized electric small antenna unit respectively correspond to the first coaxial outer conductor hole 1 7-1 and the second coaxial outer conductor hole 1 7-2 of one dual-polarized electric small antenna unit, the third coaxial outer conductor hole 1 7-3 and the fourth coaxial outer conductor hole 1 7-4 of another dual-polarized electric small antenna unit, the first coaxial outer conductor hole 2 8-1 and the second coaxial outer conductor hole 2 8-2 of one dual-polarized electric small antenna unit, the third coaxial outer conductor hole 2 8-3 and the fourth coaxial outer conductor hole 2 8-4 of another dual-polarized electric small antenna unit, and the first microstrip feeding line 9-1 and the second microstrip feeding line 9-2 of one dual-polarized electric small antenna unit, and the third microstrip feeding line 9-3 and the fourth microstrip feeding line 9-4 of another dual-polarized electric small antenna unit. By applying excitations with equal amplitudes and opposite phases to the microstrip feed lines at the co-polarized ports of the MIMO array, such as the first microstrip feed line 9-1 and the fourth microstrip feed line 9-4, or the second microstrip feed line 9-2 and the third microstrip feed line 9-3, the MIMO array can operate.

[0023] The dual-polarized electrically small antenna unit and its MIMO array disclosed herein have two specific practical applications: one is to connect to other RF components via microstrip lines (see Example 1, also known as embedded connection); the other is to integrate it into the RF circuit via a BGA label (see Example 2, also known as non-embedded connection). The following describes and explains the present invention in conjunction with these two examples.

[0024] Example 1: As attached Figure 1 -Attached Figure 6As shown, a dual-polarized electric small antenna unit of this embodiment includes: a dielectric layer, a metal copper layer bonded to the dielectric layer, and a metal via penetrating the dielectric layer;

[0025] The dielectric layer includes an upper microwave dielectric substrate 1-1, an upper bonding dielectric 2-1, a middle microwave dielectric substrate 1-2, and a lower substrate layer, which are bonded together in sequence from top to bottom. In this embodiment, the lower substrate layer includes a lower bonding dielectric 2-2 and a lower microwave dielectric substrate 1-3. The metal copper layer includes a radiation patch layer 3-1, an antenna ground layer 3-2 and a connection layer; the connection layer includes a microstrip line layer 3-4 and a feed ground layer 3-3; A radiation patch layer 3-1 is provided between the upper bonding medium 2-1 and the middle microwave dielectric substrate 1-2, and an antenna ground layer 3-2 is provided between the middle microwave dielectric substrate 1-2 and the lower bonding medium 2-2 in the lower substrate layer; a microstrip line layer 3-4 is provided at the bottom of the lower microwave dielectric substrate 1-3 in the lower substrate layer, and a feed ground layer 3-3 is provided between the lower bonding medium 2-2 and the lower microwave dielectric substrate 1-3, and the feed ground layer 3-3 corresponds to the microstrip line layer 3-4; The metal vias include metal feed through holes and metal short-circuit buried holes 5-1; The metal feed vias include a first metal feed via 4-1 and a second metal feed via 4-2. These metal feed vias penetrate the dielectric layer, from the upper microwave dielectric substrate 1-1 to the lower microwave dielectric substrate 1-3, connecting the radiating patch layer 3-1 to the microstrip line layer 3-4. Several metal short-circuit buried vias 5-1 are provided. These metal short-circuit buried vias 5-1 penetrate the middle microwave dielectric substrate 1-2 and connect to the antenna ground layer 3-2. The metal short-circuit buried vias 5-1 are inscribed within the edges of the middle microwave dielectric substrate 1-2 and surround the antenna to form a square frame. The spacing between the metal short-circuit buried vias 5-1 is twice their diameter.

[0026] The radiating patch layer 3-1 is located between the middle microwave dielectric substrate 1-2 and the upper adhesive layer 2-1. Through the PCB lamination process, the radiating patch layer 3-1 is embedded in the upper adhesive layer 2-1. A first radiating patch 6-1 is provided within the radiating patch layer 3-1, penetrated by a metal feed hole. The first radiating patch 6-1 is a square patch with four chamfered corners and is positioned at a 45-degree angle relative to the middle microwave dielectric substrate 1-2. The metal feed hole is located in the upper half of the first radiating patch 6-1, on a diagonal line of the plane of the middle microwave dielectric substrate 1-2. The metal feed holes are symmetrical about the diagonal line of the first radiating patch 6-1 and are equidistant from both sides of the upper half of the first radiating patch 6-1. Adjusting the size and angle of the first radiating patch 6-1 can change the operating frequency of the antenna. Increasing the size or decreasing the angle shifts the operating frequency toward lower frequencies; decreasing the size or increasing the angle shifts the operating frequency toward higher frequencies.

[0027] The outer dimensions of the antenna ground layer 3-2 and the feed ground layer 3-3 are equal to the dimensions of the middle-layer microwave dielectric substrate 1-2.

[0028] The antenna ground layer 3-2 has coaxial outer conductor holes (I) of equal size, comprising a first coaxial outer conductor hole 7-1 and a second coaxial outer conductor hole 7-2. The feed ground layer 3-3 has coaxial outer conductor holes (II) of equal size, comprising a first coaxial outer conductor hole 8-1 and a second coaxial outer conductor hole 8-2. The I and II coaxial outer conductor holes correspond to the metal feed holes and share the same axis. The I and II coaxial outer conductor holes are larger than the metal feed holes.

[0029] Microstrip feed lines are provided on microstrip layer 3-4. These microstrip feed lines correspond to and cover the metal feed vias. The microstrip feed lines include a first microstrip feed line 9-1 and a second microstrip feed line 9-2. Both microstrip feed lines are 50Ω. These microstrip feed lines are connected to the first radiating patch 6-1 via the metal feed vias.

[0030] The sizes and relative positions of the first coaxial outer conductor hole and the second coaxial outer conductor hole are completely consistent, corresponding to the metal feed through hole, forming a coaxial line feeding structure with a characteristic impedance of 50Ω.

[0031] As attached Figure 7 -Attached Figure 11As shown, this embodiment also discloses a MIMO array of dual-polarized electric small antennas, including two completely identical dual-polarized electric small antenna units, which are mirror-symmetrical in left and right directions and share a common dielectric layer; the radiation patches in the two dual-polarized electric small antenna units are mirror-symmetrical about the center of the intermediate microwave dielectric substrate 1-2; the microstrip feed lines of the same polarization ports apply excitations with equal amplitudes and opposite phases; and two comb-shaped defective ground gaps 10-1 are opened on the antenna ground layer 3-2 between adjacent dual-polarized electric small antenna units, and the two comb-shaped defective ground gaps are mirror-symmetrical; the comb-shaped defective ground gaps 10-1 are periodic structures, the width of the comb handle is equal to the width of the comb teeth, and the spacing between the comb teeth is approximately twice the width of the comb teeth.

[0032] Specifically, the first radiation patch 6-1 in one dual-polarized electric small antenna unit and the second radiation patch 6-2 in the other dual-polarized electric small antenna unit are mirror-symmetrical about the center of the middle microwave dielectric substrate 1-2 of the MIMO array.

[0033] The first metal feeding through hole 4-1 and the second metal feeding through hole 4-2 of one dual-polarized electric small antenna unit, and the third metal feeding through hole 4-3 and the fourth metal feeding through hole 4-4 of another dual-polarized electric small antenna unit respectively correspond to the first coaxial outer conductor hole 1 7-1 and the second coaxial outer conductor hole 1 7-2 of one dual-polarized electric small antenna unit, the third coaxial outer conductor hole 1 7-3 and the fourth coaxial outer conductor hole 1 7-4 of another dual-polarized electric small antenna unit, the first coaxial outer conductor hole 2 8-1 and the second coaxial outer conductor hole 2 8-2 of one dual-polarized electric small antenna unit, the third coaxial outer conductor hole 2 8-3 and the fourth coaxial outer conductor hole 2 8-4 of another dual-polarized electric small antenna unit, and the first microstrip feeding line 9-1 and the second microstrip feeding line 9-2 of one dual-polarized electric small antenna unit, and the third microstrip feeding line 9-3 and the fourth microstrip feeding line 9-4 of another dual-polarized electric small antenna unit. By applying excitations with equal amplitudes and opposite phases to the microstrip feed lines at the co-polarized ports of the MIMO array, such as the first microstrip feed line 9-1 and the fourth microstrip feed line 9-4, or the second microstrip feed line 9-2 and the third microstrip feed line 9-3, the MIMO array can operate.

[0034] The antenna ground layer 3-2 of the dual-polarized electrically small antenna MIMO array features comb-shaped defect gaps 10-1, with two comb-shaped defect gaps being mirror-image symmetrical. The teeth in these comb-shaped defect gaps 10-1 are periodic, with the width of the handle equal to the width of the teeth. A single tooth is 0.8 mm long and 0.2 mm wide, with a spacing of 0.8 mm between adjacent teeth.

[0035] The dual-polarized electrical small antenna unit and its MIMO array in this embodiment have the same stacked structure and metal via type. The upper microwave dielectric substrate 1-1 is Rogers 3010 with a thickness of 0.64 mm; the middle microwave dielectric substrate 1-2 is TLY-5 with a thickness of 1.52 mm; the lower microwave dielectric substrate 1-3 is Rogers 4350B with a thickness of 0.17 mm; the upper bonding medium 2-1 and the lower bonding medium 2-2 are Rogers 4450F with a thickness of 0.204 mm.

[0036] The dual-polarized electrically small antenna element and its MIMO array in this embodiment operate at a central frequency of 13 GHz, with element dimensions of 4.5 mm × 4.5 mm × 2.8 mm. The antenna element has a ka of 0.92, where k is the wave number and a is the radius of the smallest sphere enclosing the antenna. The dual-polarized electrically small antenna MIMO array measures 13.5 mm × 4.5 mm × 2.8 mm, and the element pitch (the distance between the centers of two elements in the MIMO array) is 9 mm.

[0037] In this embodiment, the upper microwave dielectric substrate uses a high dielectric constant substrate, which is loaded and covered on a square radiating patch to achieve antenna miniaturization. Two coaxial feeds excite mutually orthogonal patch radiation patterns, achieving dual-polarization characteristics with good isolation. The MIMO array is a 1×2 array with left-right mirror symmetry. The metal antenna ground layer of the array has comb-shaped periodic defect gaps to suppress coupling between array elements. The antenna has a planar size of 0.195λ×0.195λ. λ is a wavelength of 13 GHz and operates in the 12.7-13.25 GHz frequency band. It has high efficiency, high gain, and a wide beam, making it suitable for the application requirements of 5GFR3 frequency band and future 6G wireless network terminal communications.

[0038] The simulation verification results of a dual-polarized electrically small antenna unit and a MIMO array of dual-polarized electrically small antenna units implemented in this embodiment are as follows: like Figure 12 As shown in the S parameter and gain simulation results of a dual-polarized electric small antenna unit in this embodiment, S11 and S22 are the reflection coefficients of ports 1 and 2 respectively; S21 is the transmission coefficient of port 2 when port 1 is excited; S12 is the transmission coefficient of port 1 when port 2 is excited, port 1 corresponds to a 4-1 feed coaxial, and port 2 corresponds to a 4-1 feed coaxial. Figure 12 The arrow at the top of the middle line points to the gain vertical axis on the right, representing the gain line. From this line, we can see that the maximum gain is 3.38dBi, and the gain fluctuation within the operating frequency band is less than 0.58dB; Figure 12The two line arrows at the bottom center point to the S-parameter ordinate on the left, indicating that the S-parameter simulation curves of S11 and S22 overlap, and the S-parameter simulation curves of S12 and S21 overlap. These two lines show that the impedance bandwidth covers 12.56 GHz to 13.37 GHz, and that the port reflection coefficient is less than -10 dB.

[0039] like Figure 13 As shown, in the antenna efficiency simulation results of a dual-polarized electric small antenna unit in this embodiment, the maximum efficiency is 94.8%, and the antenna efficiency within the working frequency band is higher than 85%, which is higher than the working efficiency of a conventional electric small antenna.

[0040] Figure 14 The simulation results of the radiation patterns of a dual-polarized electrically small antenna unit designed at 13 GHz in the two planes of phi=45° and phi=–45° are given. The designed dual-polarized electrically small antenna unit has a wide beamwidth in the two main planes, and the main polarization cross-polarization ratio can reach 15 dB, and remains stable within a wide frequency band.

[0041] Figure 15 and Figure 16 A schematic diagram of the impedance bandwidth and gain simulation results of a MIMO array of dual-polarized electrically small antenna units is given. S11, S22, S33, and S44 are the reflection coefficients of ports 1, 2, 3, and 4, respectively. Figure 15 In the figure, it is represented by overlapping lines, with the line arrows pointing to the S parameter ordinate on the left. Port 1 corresponds to the 4-1 feed coaxial, port 2 corresponds to the 4-1 feed coaxial, port 3 corresponds to the 4-3 feed coaxial, and port 4 corresponds to the 4-4 feed coaxial. Figure 16 The three lines in the figure represent the transmission coefficients of the ports, indicating that the impedance bandwidth of the antenna array is 12.61 GHz -13.44 GHz, and the isolation between the ports is greater than 12 dB; Figure 15 The arrow at the top of the middle line points to the gain vertical coordinate on the right, representing the gain line. From this line, we can see that the maximum gain is 4.32dBi.

[0042] Figure 17 The efficiency simulation results of a MIMO array of dual-polarized electrically small antenna units are given. Due to the compact arrangement of the antenna array, the element spacing, that is, the distance between the centers of adjacent dual-polarized electrically small antenna units, is only 0.39λ, where λ is the wavelength corresponding to 13 GHz. Its efficiency is higher than 60% within the operating bandwidth, and the maximum efficiency is 82.6%.

[0043] Figure 18The simulation results of the radiation patterns of a MIMO array of dual-polarized electrically small antenna units designed at 13 GHz in the phi=45° and phi=–45° planes are given. The radiation pattern of the designed dual-polarized electrically small antenna MIMO array has no side lobes, a 3dB beamwidth of 100 degrees, and a main polarization cross-polarization ratio of up to 15dB.

[0044] The above results show that the dual-polarized electrically small antenna unit and the MIMO array of dual-polarized electrically small antenna units designed in this embodiment have the characteristics of high efficiency, high isolation, wide beamwidth, good cross-polarization suppression and high gain, and are suitable for 5G and 6G mobile terminal applications and satellite transceiver antenna applications.

[0045] Example 2: like Figure 19 As shown, a dual-polarized electric small antenna unit of this embodiment includes: a dielectric layer, a metal copper layer bonded to the dielectric layer, and a through hole penetrating the dielectric layer;

[0046] The dielectric layer includes an upper microwave dielectric substrate 1-1, an upper adhesive medium 2-1, a middle microwave dielectric substrate 1-2, and a lower substrate layer bonded together from top to bottom. In this embodiment, the lower substrate layer includes a first antenna unit bottom plate 11-1. The metal copper layer includes a radiation patch layer 3-1, an antenna ground layer 3-2, and a connection layer; the connection layer includes a first solder ball layer 13-1 and a first stepped impedance transformation line 14-1; A radiation patch layer 3-1 is provided between the upper bonding medium 2-1 and the middle microwave dielectric substrate 1-2, and a first solder ball layer 13-1 is provided between the middle microwave dielectric substrate 1-2 and the first antenna unit bottom plate 11-1. The first solder ball layer 13-1 is a solder ball array, each solder ball having a diameter of 0.25 mm, and a spacing between adjacent solder balls of no less than 0.5 mm. The metal vias include metal feed through holes and metal short-circuit buried holes 5-1; The metal feed vias include a first metal feed via 4-1 and a second metal feed via 4-2. These metal feed vias penetrate the dielectric layer, namely, from the upper microwave dielectric substrate 1-1 to the first antenna unit base plate 11-1, connecting the radiating patch layer 3-1 to the first stepped impedance transformation line 14-1. The first and second metal feed vias 4-1 and 4-2 connect to two solder balls in the first solder ball layer 13-1. Several metal short-circuit buried vias 5-1 are provided. These metal short-circuit buried vias 5-1 penetrate the middle microwave dielectric substrate 1-2 and connect to the antenna ground layer 3-2. The metal short-circuit buried vias 5-1 are inscribed within the edge of the middle microwave dielectric substrate 1-2 and surround it to form a square frame. The spacing between the metal short-circuit buried vias 5-1 is twice their diameter.

[0047] The radiating patch layer 3-1 is located between the middle microwave dielectric substrate 1-2 and the upper adhesive layer 2-1. Through the PCB lamination process, the radiating patch layer 3-1 is embedded in the upper adhesive layer 2-1. A first radiating patch 6-1 is provided within the radiating patch layer 3-1, penetrated by a metal feed hole. The first radiating patch 6-1 is a square patch with four chamfered corners and is positioned at a 45-degree angle relative to the middle microwave dielectric substrate 1-2. The metal feed hole is located in the upper half of the first radiating patch 6-1, on a diagonal line of the plane of the middle microwave dielectric substrate 1-2. The metal feed holes are symmetrical about the diagonal line of the first radiating patch 6-1 and are equidistant from both sides of the upper half of the first radiating patch 6-1. Adjusting the size and angle of the first radiating patch 6-1 can change the operating frequency of the antenna. Increasing the size or decreasing the angle shifts the operating frequency toward lower frequencies; decreasing the size or increasing the angle shifts the operating frequency toward higher frequencies.

[0048] The outer dimensions of the antenna ground layer 3-2 are equal to those of the middle-layer microwave dielectric substrate 1-2.

[0049] Antenna ground layer 3-2 has coaxial outer conductor holes (1) of the same size. These include a first coaxial outer conductor hole (1) 7-1 and a second coaxial outer conductor hole (1) 7-2. The coaxial outer conductor holes (1) correspond to the metal feed holes and share the same axis. The coaxial outer conductor holes (1) are larger than the metal feed holes.

[0050] Two first BGA base plate connection holes 16-1 of the same size are opened on the first antenna unit base plate 11-1. The first BGA base plate connection holes correspond to the positions of the metal feed through holes, which can also be understood as having the same projection position and having the same axis as the metal feed through holes; the size of the first BGA base plate connection holes is larger than the metal feed through holes.

[0051] A first stepped impedance transformation line 14-1 is provided at the bottom of the first antenna unit base plate 11-1. The material of the first antenna unit base plate 11-1 is Rogers RO4350B, with a thickness of 0.51mm and a size of 13mm×50mm. The upper layer of the first antenna unit base plate 11-1 itself is a metal ground, i.e., a copper layer with a thickness of 0.035mm. In the actual application of a dual-polarized electric small antenna unit of this embodiment, the first stepped impedance transformation line 14-1 can be directly or indirectly connected to other 50-ohm RF components, such as Figure 19 The layer where the first step impedance transformation line 14-1 is located is shown.

[0052] According to the above description, the difference between this embodiment and Example 1 is that the bottom design of the dual-polarized electrically small antenna unit is different, that is, the first local antenna unit 15-1 in this embodiment 1 is the dual-polarized electrically small antenna unit in Example 1 without the lower bonding medium 2-2, the feeding ground layer 3-3, the lower microwave dielectric substrate 1-3, and the microstrip line layer 3-4. On the basis of the first local antenna unit 15-1, a first solder ball layer 13-1, a first antenna unit bottom plate 11-1, and a first stepped impedance transformation line 14-1 are added; The first step impedance transformation line 14-1 includes two disconnected but collinear coplanar waveguide transmission lines, the spacing between the two coplanar waveguide transmission lines is the spacing between the metal feed through holes, and the adjacent endpoints of the two coplanar waveguide transmission lines correspond to the positions of the metal feed through holes; Each first-stage impedance transformation line 14-1 comprises four sections of coplanar waveguide transmission lines with different impedances. As they move away from the antenna body, the coplanar waveguide impedances are 116 ohms, 44.5 ohms, 76.3 ohms, and 50 ohms, respectively. The last section, the coplanar waveguide transmission line away from the antenna body, has a 50 ohm impedance. The remaining three sections of the stepped transmission line achieve impedance matching at specific frequencies. The core concept is to insert multiple sections of stepped transmission lines with varying characteristic impedances between two sections of transmission lines with different characteristic impedances, thereby reducing the reflection coefficient and achieving impedance matching over a wide frequency range. In this embodiment, this structural design aims to offset the impact of the metal ground layer on the first antenna unit base plate 11-1 on the antenna impedance matching.

[0053] As attached Figure 20 As shown, this embodiment also discloses a MIMO array of dual-polarized electrical small antennas, including two identical dual-polarized electrical small antenna units, which are mirror-symmetrical and share a common dielectric layer. The second antenna array base plate 11-2 in the MIMO array is made of Rogers RO4350B, has a thickness of 0.51mm, and measures 23mm x 50mm. The radiating patches in the two dual-polarized electrical small antenna units are mirror-symmetrical about the center of the intermediate microwave dielectric substrate 1-2. Microstrip feed lines at the same polarization ports apply excitation with equal amplitude and opposite phase. The second local antenna unit 15-2 in the MIMO array is composed of two first local antenna units 15-1 arranged in a central mirror-symmetrical manner. The antenna ground layer 3-2 is directly connected to the BGA solder balls in the second solder ball layer 13-2, and after the four metal feed through holes 4-1, 4-2, 4-3, and 4-4 are soldered to the corresponding solder balls, the RF connection is achieved through the second BGA base plate connection hole 16-2 on the second antenna unit base plate 11-2 and the second stepped impedance transformation line 14-2 on the back.

[0054] like Figure 21As shown in the S parameter and gain simulation results of a dual-polarized electric small antenna unit in this embodiment, S11 and S22 are the reflection coefficients of ports 1 and 2 respectively; S21 is the transmission coefficient of port 2 when port 1 is excited; S12 is the transmission coefficient of port 1 when port 2 is excited, Figure 22 The arrow at the top of the middle line points to the gain vertical coordinate on the right, representing the gain line. From this line, we can see that the maximum gain is 4.5dBi. Within the operating frequency band, that is, from 12.64GHz to 13.38GHz, the gain is stable, and the minimum gain is 3.2dBi. Figure 22 The two line arrows at the bottom center point to the S-parameter ordinate on the left, indicating that the S-parameter simulation curves of S11 and S22 overlap, and the S-parameter simulation curves of S12 and S21 overlap. These two lines show that the impedance bandwidth is 12.64 GHz to 13.38 GHz, and the isolation is better than 12 dB.

[0055] like Figure 22 As shown, the maximum efficiency of a dual-polarized electrically small antenna unit in this embodiment is 86%, and the antenna efficiency within the working frequency band is higher than 72%.

[0056] Figure 23 The simulation results of the radiation patterns of a dual-polarized electrically small antenna unit designed at 13 GHz in the phi=45° and phi=–45° planes are given. The designed antenna has a wide beamwidth in the two main planes, good backward suppression, improved forward radiation gain, and the main polarization cross-polarization ratio can reach 13 dB.

[0057] Figure 24 and Figure 25 A schematic diagram of the impedance bandwidth and gain simulation results of a MIMO array of dual-polarized electrically small antenna units is given. S11, S22, S33, and S44 are the reflection coefficients of ports 1, 2, 3, and 4, respectively. Figure 24 It is represented by overlapping lines, with the line arrows pointing to the left S parameter ordinate. Figure 25 The three lines in the figure represent the transmission coefficients between different ports, indicating that the impedance bandwidth of the antenna array is 12.52-13.86 GHz and the isolation between the ports is greater than 12 dB. Figure 24 The arrow at the top of the middle line points to the gain vertical coordinate on the right, representing the gain line. From this line, we can see that the maximum gain is 6.2dBi.

[0058] Figure 26 The efficiency simulation results of a MIMO array with dual-polarized electrically small antenna units are given, and its efficiency is higher than 80% within the working bandwidth.

[0059] Figure 27The simulation results of the radiation patterns of a MIMO array of dual-polarized electrically small antenna units designed at 13 GHz in the phi=45° and phi=–45° planes are given. The designed antenna array has a wide beamwidth in the two main planes. The 3dB beamwidth on the -45-degree plane is 80 degrees, and the main polarization cross-polarization ratio is better than 16dB.

[0060] Figures 21-27 The results show that the dual-polarized electric small antenna unit and its MIMO array based on BGA packaging designed in Example 2 have the characteristics of simple processing, high efficiency, wide beam width, high front-to-back ratio, good cross-polarization suppression and high gain. It is suitable for integrated chip packaging, easy to test and has good overall heat dissipation. It is suitable for connecting the dual-polarized electric small antenna unit and MIMO array with other microwave radio frequency components, reducing the design complexity.

[0061] The “first” and “second” in the names such as “first” and “second” mentioned in the embodiments of this application are only used as name identifiers and do not represent the first or second in order or importance.

[0062] 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 principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A dual-polarized electrically small antenna unit, characterized in that: include: A dielectric layer, a metal copper layer bonded to the dielectric layer, and a metal via penetrating the dielectric layer; The dielectric layer comprises an upper microwave dielectric substrate (1-1), an upper bonding medium (2-1), a middle microwave dielectric substrate (1-2) and a lower base plate layer, which are bonded in sequence from top to bottom. The metal copper layer includes a radiation patch layer (3-1), an antenna ground layer (3-2) and a connection layer; A radiation patch layer (3-1) is provided between the upper bonding medium (2-1) and the middle microwave dielectric substrate (1-2); an antenna grounding layer (3-2) is provided between the middle microwave dielectric substrate (1-2) and the lower substrate layer; a connection layer is provided at the bottom of the lower substrate layer; a first radiation patch (6-1) is provided in the radiation patch layer (3-1), and the first radiation patch (6-1) is penetrated by a metal feed through hole; Metal vias include metal feed through holes and metal short-circuit buried holes (5-1); The metal feed through hole comprises a first metal feed through hole (4-1) and a second metal feed through hole (4-2). The metal feed through hole penetrates the dielectric layer, that is, penetrates from the upper microwave dielectric substrate (1-1) to the lower base plate layer, thereby connecting the radiation patch layer (3-1) and the connection layer. There are a plurality of metal short-circuit buried vias (5-1), which penetrate the middle microwave dielectric substrate (1-2) and are connected to the antenna ground layer (3-2).

2. The dual-polarized electric small antenna unit according to claim 1, characterized in that: The metal short-circuit buried holes (5-1) are inscribed with the edges of the middle-layer microwave dielectric substrate (1-2) and surround to form a square frame. The spacing between the metal short-circuit buried holes (5-1) is twice the diameter of the metal short-circuit buried holes (5-1).

3. The dual-polarized electrical small antenna unit according to claim 1, characterized in that: The first radiation patch (6-1) is a square patch with four corners cut off and is placed at a 45-degree angle relative to the middle-layer microwave dielectric substrate (1-2). The metal feed through hole is symmetrical about the diagonal line of the first radiation patch (6-1) and is equidistant from the two sides of the upper half of the first radiation patch (6-1).

4. The dual-polarized electric small antenna unit according to claim 1, characterized in that: The lower substrate layer includes a lower bonding medium (2-2) and a lower microwave dielectric substrate (1-3); the connection layer includes a microstrip line layer (3-4) and a feed ground layer (3-3); an antenna ground layer (3-2) is provided between the middle microwave dielectric substrate (1-2) and the lower bonding medium (2-2) in the lower substrate layer; a microstrip line layer (3-4) is provided at the bottom of the lower microwave dielectric substrate (1-3) in the lower substrate layer, and a feed ground layer (3-3) is provided between the lower bonding medium (2-2) and the lower microwave dielectric substrate (1-3); the feed ground layer (3-3) corresponds to the microstrip line layer (3-4).

5. The dual-polarized electric small antenna unit according to claim 4, characterized in that: A microstrip feeding line is provided on the microstrip line layer (3-4), the microstrip feeding line corresponds to the metal feeding through-hole and covers the metal feeding through-hole, the microstrip feeding line includes a first microstrip feeding line (9-1) and a second microstrip feeding line (9-2), and the microstrip feeding line is a 50Ω microstrip feeding line; the microstrip feeding lines are respectively connected to the first radiation patch (6-1) through the metal feeding through-hole.

6. The dual-polarized electric small antenna unit according to claim 4, characterized in that: The antenna grounding layer (3-2) is provided with a coaxial outer conductor hole one of the same size, the coaxial outer conductor hole one includes a first coaxial outer conductor hole one (7-1) and a second coaxial outer conductor hole one (7-2); the feed grounding layer (3-3) is provided with a coaxial outer conductor hole two of the same size, the coaxial outer conductor hole two includes a first coaxial outer conductor hole two (8-1) and a second coaxial outer conductor hole two (8-2); the coaxial outer conductor hole one and the coaxial outer conductor hole two correspond to the positions of the metal feed through hole and have the same axis as the metal feed through hole; the sizes of the coaxial outer conductor hole one and the coaxial outer conductor hole two are larger than the metal feed through hole.

7. A MIMO array of dual-polarized electrically small antenna units, characterized in that: The invention comprises two identical dual-polarization electric small antenna units, wherein the dual-polarization electric small antenna unit is a dual-polarization electric small antenna unit as described in any one of claims 1 to 6, the two dual-polarization electric small antenna units are mirror-symmetrical in left and right directions, and share a common dielectric layer; the radiation patches in the two dual-polarization electric small antenna units are mirror-symmetrical in center about the intermediate microwave dielectric substrate (1-2); the microstrip feed lines of the same polarization ports apply excitations with equal amplitudes and opposite phases, and two comb-shaped defective ground gaps (10-1) are opened on the antenna ground layer (3-2) between adjacent dual-polarization electric small antenna units, and the two comb-shaped defective ground gaps are mirror-symmetrical.

8. A dual-polarized electric small antenna unit, characterized in that: include: A dielectric layer, a metal copper layer bonded to the dielectric layer, and a metal via penetrating the dielectric layer; The dielectric layer comprises an upper microwave dielectric substrate (1-1), an upper bonding medium (2-1), a middle microwave dielectric substrate (1-2) and a lower base plate layer, which are bonded in sequence from top to bottom. The metal copper layer includes a radiation patch layer (3-1), an antenna ground layer (3-2) and a connection layer; A radiation patch layer (3-1) is provided between the upper bonding medium (2-1) and the middle microwave dielectric substrate (1-2); an antenna grounding layer (3-2) is provided between the middle microwave dielectric substrate (1-2) and the lower substrate layer; a connection layer is provided at the bottom of the lower substrate layer; a first radiation patch (6-1) is provided in the radiation patch layer (3-1), and the first radiation patch (6-1) is penetrated by a metal feed through hole; Metal vias include metal feed through holes and metal short-circuit buried holes (5-1); The metal feed through hole comprises a first metal feed through hole (4-1) and a second metal feed through hole (4-2). The metal feed through hole penetrates the dielectric layer, that is, penetrates from the upper microwave dielectric substrate (1-1) to the lower base plate layer, thereby connecting the radiation patch layer (3-1) and the connection layer. There are a plurality of metal short-circuit buried vias (5-1). The metal short-circuit buried vias (5-1) penetrate the middle microwave dielectric substrate (1-2) and are connected to the antenna ground layer (3-2). The lower substrate layer includes a first antenna unit bottom plate (11-1); the connection layer includes a first solder ball layer (13-1) and a first stepped impedance transformation line (14-1); the first solder ball layer (13-1) is arranged between the middle microwave dielectric substrate (1-2) and the first antenna unit bottom plate (11-1); and the first stepped impedance transformation line (14-1) is arranged at the bottom of the first antenna unit bottom plate (11-1).

9. The dual-polarized electric small antenna unit according to claim 8, characterized in that: Two first BGA base plate connection holes (16-1) of the same size are opened on the first antenna unit base plate (11-1), and the first BGA base plate connection holes correspond to the positions of the metal feed through holes; the first step impedance transformation line (14-1) includes two coplanar waveguide transmission lines that are not connected but collinear, the spacing between the two coplanar waveguide transmission lines is the spacing between the metal feed through holes, and the adjacent end points of the two coplanar waveguide transmission lines correspond to the positions of the metal feed through holes, each first step impedance transformation line (14-1) includes four sections of coplanar waveguide transmission lines with different impedances, and the coplanar waveguide impedances are 116 ohms, 44.5 ohms, 76.3 ohms, and 50 ohms in the direction away from the antenna body.

10. A MIMO array of dual-polarized electrically small antenna units, characterized in that: The invention comprises two identical dual-polarized electric small antenna units, wherein the dual-polarized electric small antenna unit is a dual-polarized electric small antenna unit as described in claim 8 or 9, the two dual-polarized electric small antenna units are mirror-symmetrical in left and right directions, and share a common dielectric layer; the radiation patches in the two dual-polarized electric small antenna units are mirror-symmetrical in center about the intermediate microwave dielectric substrate (1-2); and the microstrip feed lines of the same polarization ports apply excitations with equal amplitudes and opposite phases.

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