Electrically small antenna based on magic cube structure

Abstract

The invention relates to the technical field of wireless communication, and discloses an electrically small antenna based on a Rubik's cube structure, which comprises a metal ring structure formed by three-dimensional orthogonal folding, a cube Rubik's cube structure formed by splicing at least three different types of substrates, and the numbers of the three types of substrates are different; the metal ring structures are printed on the six substrates of the cube magic cube structure through microstrip lines; wherein the metal ring structure excites the combination of the multi-magnetic coupling ring and the galvanic coupling in a single-feed or double-feed mode, and an omnidirectional radiation or dual polarization function under a small electrical size is realized. According to the invention, an omnidirectional radiation or dual polarization function can be realized under a small electric size (kilt; 1), and the cubic frame formed by self-splicing of the substrates has an electromagnetic isolation characteristic without additional packaging.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and more specifically to an electrically small antenna based on a Rubik's Cube structure. Background Technology

[0002] In the field of wireless communication technology, electrically small antennas have broad application prospects in miniaturized devices because their size is much smaller than the operating wavelength (satisfying the electrically small size parameter ka < 1, where k is the wave number and a is the minimum sphere radius surrounding the antenna).

[0003] However, traditional electrically small antennas face a contradiction between performance improvement and structural complexity: on the one hand, most existing technologies focus on improving the performance of a single antenna through independent complex structures (such as increasing gain, bandwidth or tuning range), but such designs are difficult to balance miniaturization and functional diversification requirements; on the other hand, modern radio frequency communication systems have put forward higher requirements for antennas to "achieve multi-functional switching on the basis of miniaturization", such as achieving different functions such as omnidirectional radiation and dual polarization under the same structure, in order to adapt to complex communication scenarios (such as multi-band communication, anti-interference transmission, etc.).

[0004] In existing technologies, although magnetic dipole loop antennas can be folded in three dimensions to compress their size, a single folded structure can only achieve a fixed function and requires complex feeding or additional components to switch modes. For example, traditional single-polarized antennas cannot meet the requirements of orthogonal polarization communication, while dual-polarized antennas often suffer from size limitations or insufficient isolation due to structural complexity. In addition, the limitations of substrate assembly methods also restrict functional expansion: existing designs mostly use a single type of substrate, making it difficult to achieve topology reconstruction through simple splicing.

[0005] Therefore, how to achieve functional diversification through modular structural design under the constraint of small electrical size has become an urgent technical problem to be solved. Summary of the Invention

[0006] In view of this, the present invention provides an electrically small antenna based on a Rubik's Cube structure to solve the problem of how to achieve functional diversity through modular structural design under the constraint of electrically small size.

[0007] This invention provides a small electrically conductive antenna based on a Rubik's Cube structure, comprising:

[0008] A metal ring structure formed by three-dimensional orthogonal folding;

[0009] A cube structure is formed by splicing together at least three different types of substrates, with varying numbers of the three types of substrates;

[0010] The metal ring structure is printed by microstrip lines on the six substrates of the cube-shaped structure;

[0011] The metal ring structure excites a combination of multiple magnetic couplers and electric couples through single-feed or double-feed methods, thereby achieving omnidirectional radiation or dual-polarization functions with small electrical dimensions.

[0012] The cube-structured electrically small antenna forms a multi-loop coupling path through a three-dimensional orthogonally folded metal ring structure. It utilizes unequal numbers of three types of substrates (with differences in dielectric constant) to construct an asymmetric electromagnetic environment within the cube assembly. The microstrip lines of the metal rings are continuously printed along the surfaces of six substrates, forming a closed conductive loop spanning the three-dimensional orthogonal plane. In a single-feed mode, a single feed point excites segmented metal rings on different substrates, creating a phase difference in the current along the folded path and simultaneously exciting a mixed radiation mode of multiple magnetic dipole rings and electric dipoles. In a dual-feed mode, two sets of orthogonally distributed feed points drive vertical and horizontal metal ring branches respectively. The difference in substrate dielectric properties controls the current distribution, spatially decoupling the two polarization components. The three-dimensional orthogonal folded structure enhances radiation efficiency through inter-ring coupling of the magnetic dipole rings, while the electric dipole components compensate for pattern distortion under small electrical dimensions through substrate asymmetry. Ultimately, it achieves omnidirectional radiation or dual polarization functions within a small electrical size (ka<1), and the cube frame formed by the self-assembly of the substrates possesses electromagnetic isolation characteristics without additional encapsulation.

[0013] In one optional embodiment, the substrate includes a first structure feeding substrate, a second structure feeding substrate, and a non-feeding substrate.

[0014] The substrate has slots around its perimeter, and adjacent substrates are joined together by the slots.

[0015] In this embodiment, the first and second structure feed substrates are vertically interlocked with the non-feed substrate via slots, forming a three-dimensional orthogonal support for the cubic frame. The slot depth of the first structure feed substrate is greater than that of the second structure feed substrate, so that a stepped contact surface is formed when the non-feed substrate is embedded, ensuring that the feed path is isolated from the non-feed substrate. The microstrip line of the first structure feed substrate extends along the edge of the slot to the surface of the adjacent substrate, directly forming a coplanar feed coupling with the metal ring segment of the second structure feed substrate. The inner wall of the slot of the non-feed substrate is covered with an insulating layer to suppress parasitic current between adjacent metal rings. By adjusting the slot spacing between the first and second structure feed substrates, the feed coupling strength is controlled. At the same time, the slot limit of the non-feed substrate is used to achieve precise constraint on the folding angle of the metal ring, so that the three-dimensional orthogonally spliced ​​metal ring generates multi-loop phase-synchronous magnetic dipole-electric dipole composite radiation under single / dual feed excitation.

[0016] In one alternative embodiment, the microstrip line of the metal ring structure is printed on the inner surface of the substrate, and the width of the microstrip line is adjusted according to the feed substrate surface to achieve impedance matching.

[0017] In this embodiment, the first and second structure feed substrates are vertically interlocked with the non-feed substrate via slots, forming a three-dimensional orthogonal support for the cubic frame. The slot depth of the first structure feed substrate is greater than that of the second structure feed substrate, so that a stepped contact surface is formed when the non-feed substrate is embedded, ensuring that the feed path is isolated from the non-feed substrate. The microstrip line of the first structure feed substrate extends along the edge of the slot to the surface of the adjacent substrate, directly forming a coplanar feed coupling with the metal ring segment of the second structure feed substrate. The inner wall of the slot of the non-feed substrate is covered with an insulating layer to suppress parasitic current between adjacent metal rings. By adjusting the slot spacing between the first and second structure feed substrates, the feed coupling strength is controlled. At the same time, the slot limit of the non-feed substrate is used to achieve precise constraint on the folding angle of the metal ring, so that the three-dimensional orthogonally spliced ​​metal ring generates multi-loop phase-synchronous magnetic dipole-electric dipole composite radiation under single / dual feed excitation.

[0018] In one optional embodiment, the single-feed structure includes a metal ring formed by three-dimensional orthogonal folding of two straight metal strips and a bent metal strip. The ends of the two straight metal strips are connected to metal pads for exciting a combination of multiple magnetic couples and electric couples to achieve 45-degree omnidirectional radiation.

[0019] In one optional embodiment, the doubly fed structure includes two orthogonally symmetrical metal rings, each of which is composed of two straight metal strips and a bent metal strip. The ends of the two straight metal strips are connected to metal pads to form orthogonal feeding ports, thereby exciting horizontal polarization and vertical polarization respectively.

[0020] In one optional implementation, the isolation between the two metal rings of the doubly fed structure is greater than 38dB, and the 10dB bandwidth of the operating frequency band is not less than 5%.

[0021] In one optional embodiment, the substrate is made of Rogers 4003c, which has a relative permittivity of 3.38 and a tangent loss angle of 0.0027.

[0022] The side length 'a' of the cube structure is 19-21mm, the substrate thickness 't' is 0.8-0.9mm, and the slot splicing length is 4-6mm.

[0023] In one optional embodiment, the microstrip width of the metal ring is 0.4 mm or 1.5 mm, and the gap g of the bent metal strip is 4 mm.

[0024] In one optional implementation, the electrical dimensions of the cube structure satisfy ka < 1, where k is the wave number, a is the minimum sphere radius surrounding the antenna, and the operating frequency band covers 1.21-1.22 GHz or 2.39-2.52 GHz.

[0025] The present invention has the following advantages over the prior art:

[0026] Compared with existing technologies, the electronically small antenna based on a Rubik's Cube structure proposed in this invention is the first to propose forming multiple combinations of magnetic and electrical couplers by folding a single magnetic dipole ring in three dimensions orthogonally. By combining three types of substrates and selecting six pieces of varying numbers to construct a Rubik's Cube structure, and then self-encapsulating it, impedance matching can be achieved simply by adjusting the microstrip line width of the feed substrate. Furthermore, selecting six more pieces of varying numbers from the three types of substrates can directly construct multiple coupled magnetic and electrical couple combinations, achieving high-isolation dual-polarization functionality. Moreover, this folded structure can also be combined with dielectric blocks, lumped elements, and other structures to achieve new functions. Therefore, this design features small electrical size and ease of topology development. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the first folded structure of the electrically small antenna based on the Rubik's Cube structure provided in the embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the second folded structure of the electrically small antenna based on the Rubik's Cube structure provided in the embodiments of the present invention;

[0030] Figure 3 This is a schematic diagram of the first structure feeding substrate in the electrically small antenna based on the Rubik's Cube structure provided in the embodiments of the present invention;

[0031] Figure 4 This is a schematic diagram of the second structure feeding substrate in the electrically small antenna based on the Rubik's Cube structure provided in the embodiments of the present invention;

[0032] Figure 5 This is a schematic diagram of the non-feed substrate in the electrically small antenna based on the Rubik's Cube structure provided in the embodiments of the present invention;

[0033] Figure 6 This is a simulation diagram S11 of the first structure in the electrically small antenna based on the Rubik's Cube structure provided in this embodiment of the invention;

[0034] Figure 7 This is a 45-degree omnidirectional simulated E-plane radiation pattern of the first structure in the electrically small antenna based on the Rubik's Cube structure provided in this embodiment of the invention;

[0035] Figure 8 This is a 45-degree omnidirectional simulated H-plane radiation pattern of the first structure in the electrically small antenna based on the Rubik's Cube structure provided in this embodiment of the invention;

[0036] Figure 9 This is a simulation S-parameter diagram of the second structure in the electrically small antenna based on the Rubik's Cube structure provided in this embodiment of the invention;

[0037] Figure 10 This is a simulated E-plane radiation pattern of the horizontal polarization of the second structure in the electrically small antenna based on a Rubik's Cube structure provided in this embodiment of the invention.

[0038] Figure 11 This is a simulated horizontal polarization H-plane radiation pattern of the second structure in the electrically small antenna based on a Rubik's Cube structure provided in this embodiment of the invention.

[0039] Figure 12 This is a simulated vertical polarization E-plane radiation pattern of the second structure in the electrically small antenna based on a Rubik's Cube structure provided in this embodiment of the invention.

[0040] Figure 13 This is a simulated vertical polarization H-plane radiation pattern of the second structure in the electrically small antenna based on a Rubik's Cube structure provided in this embodiment of the invention.

[0041] Icon labels:

[0042] 1. First structure power supply substrate; 2. Second structure power supply substrate; 3. Non-power supply substrate. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] In the field of wireless communication technology, electrically small antennas have broad application prospects in miniaturized devices because their size is much smaller than the operating wavelength (satisfying the electrically small size parameter ka < 1, where k is the wave number and a is the minimum sphere radius surrounding the antenna).

[0045] However, traditional electrically small antennas face a contradiction between performance improvement and structural complexity: on the one hand, most existing technologies focus on improving the performance of a single antenna through independent complex structures (such as increasing gain, bandwidth or tuning range), but such designs are difficult to balance miniaturization and functional diversification requirements; on the other hand, modern radio frequency communication systems have put forward higher requirements for antennas to "achieve multi-functional switching on the basis of miniaturization", such as achieving different functions such as omnidirectional radiation and dual polarization under the same structure, in order to adapt to complex communication scenarios (such as multi-band communication, anti-interference transmission, etc.).

[0046] In existing technologies, while magnetic dipole loop antennas can be folded in three dimensions to compress their size, a single folded structure can only achieve a fixed function and requires complex feeding or additional components to switch modes. For example, traditional single-polarized antennas cannot meet the requirements of orthogonal polarization communication, while dual-polarized antennas often suffer from size limitations or insufficient isolation due to structural complexity. In addition, the limitations of substrate assembly methods also restrict functional expansion—existing designs mostly use a single type of substrate, making it difficult to achieve topology reconstruction through simple splicing.

[0047] Therefore, how to achieve functional diversification through modular structural design under the constraint of small electrical size has become an urgent technical problem to be solved.

[0048] The following is combined with Figures 1 to 13 The following describes embodiments of the present invention.

[0049] According to an embodiment of the present invention, in one aspect, a small electrical antenna based on a cube structure is provided, comprising a metal ring structure formed by three-dimensional orthogonal folding, and a cube structure formed by splicing together at least three different types of substrates, wherein the number of the three types of substrates is unequal; the metal ring structure is printed on six of the substrates of the cube structure by microstrip lines; wherein the metal ring structure excites a combination of multiple magnetic couplers and electric couples by single-feed or double-feed methods to achieve omnidirectional radiation or dual-polarization function under small electrical size.

[0050] The cube-structured electrically small antenna forms a multi-loop coupling path through a three-dimensional orthogonally folded metal ring structure. It utilizes unequal numbers of three types of substrates (with differences in dielectric constant) to construct an asymmetric electromagnetic environment within the cube assembly. The microstrip lines of the metal rings are continuously printed along the surfaces of six substrates, forming a closed conductive loop spanning the three-dimensional orthogonal plane. In a single-feed mode, a single feed point excites segmented metal rings on different substrates, creating a phase difference in the current along the folded path and simultaneously exciting a mixed radiation mode of multiple magnetic dipole rings and electric dipoles. In a dual-feed mode, two sets of orthogonally distributed feed points drive vertical and horizontal metal ring branches respectively. The difference in substrate dielectric properties controls the current distribution, spatially decoupling the two polarization components. The three-dimensional orthogonal folded structure enhances radiation efficiency through inter-ring coupling of the magnetic dipole rings, while the electric dipole components compensate for pattern distortion under small electrical dimensions through substrate asymmetry. Ultimately, it achieves omnidirectional radiation or dual polarization functions within a small electrical size (ka<1), and the cube frame formed by the self-assembly of the substrates possesses electromagnetic isolation characteristics without additional encapsulation.

[0051] In one embodiment, the substrate includes a first structure power-feeding substrate 1, a second structure power-feeding substrate 2, and a non-power-feeding substrate 3; the substrate is provided with slots around its perimeter, and adjacent substrates are spliced ​​together by the slots.

[0052] In this embodiment, the first structural feed substrate 1 and the second structural feed substrate 2 are vertically interlocked with the non-feed substrate 3 through slots, forming a three-dimensional orthogonal support for the cubic frame. The slot depth of the first structural feed substrate 1 is greater than that of the second structural feed substrate 2, so that a stepped contact surface is formed when the non-feed substrate 3 is embedded, ensuring that the feed path is isolated from the non-feed substrate 3. The microstrip line of the first structural feed substrate 1 extends along the edge of the slot to the surface of the adjacent substrate, directly forming a coplanar feed coupling with the metal ring segment of the second structural feed substrate 2. The inner wall of the slot of the non-feed substrate 3 is covered with an insulating layer to suppress parasitic current between adjacent metal rings. By adjusting the slot spacing between the first and second structural feed substrates 2, the feed coupling strength is controlled. At the same time, the slot limit of the non-feed substrate 3 is used to achieve precise constraint on the folding angle of the metal ring, so that the three-dimensional orthogonally spliced ​​metal ring generates multi-loop phase-synchronous magnetic dipole-electric dipole composite radiation under single / dual feed excitation.

[0053] In one embodiment, the microstrip line of the metal ring structure is printed on the inner surface of the substrate, and the width of the microstrip line is adjusted according to the feed substrate surface to achieve impedance matching.

[0054] In this embodiment, a microstrip line with a metal ring structure is printed on the inner surface of the substrate. The electromagnetic field energy is concentrated inside the cube through the inner surface layout, reducing external radiation loss and enhancing the coupling efficiency of the magnetic coupler. The width of the microstrip line on the feeding substrate surface gradually changes along the substrate splicing direction. The microstrip line width on the first structure feeding substrate surface is greater than that on the second structure feeding substrate surface to compensate for impedance mismatch caused by differences in dielectric constant. The microstrip line width on the inner surface of the non-feeding substrate 3 remains constant, serving only as a current continuity path. By adjusting the microstrip line width gradient of different feeding substrate surfaces (e.g., the first structure feeding substrate 1 narrows linearly from the center to the edge, and the second structure feeding substrate 2 uses stepped width segments), the equivalent impedance of the transition region between adjacent substrates in the three-dimensional folding path changes continuously and gradually, thereby achieving wideband matching at single / dual feeding ports and suppressing resonant frequency shift caused by discontinuities at the substrate splicing interface, ultimately ensuring a stable omnidirectional radiation pattern.

[0055] In one embodiment, such as Figure 1 In the structure shown, the single-feed structure includes a metal ring, which is formed by three-dimensional orthogonal folding of two straight metal strips a1 and b1 and a bent metal strip. The ends of the two straight metal strips a1 and b1 are connected to metal pads c1 and d1, which are used to excite the combination of multiple magnetic couples and electric couples to achieve 45-degree omnidirectional radiation. Figure 3 This is a schematic diagram of the first structure feed substrate 1 in the electrically small antenna based on a cube structure provided in this embodiment. Two metal pads have metal vias for feeding. The radius of the metal pads is r3, and the radii of the metal vias for feeding on the metal pads are r1 and r2, respectively.

[0056] In one embodiment, such as Figure 2 In the structure shown, the doubly fed structure includes two orthogonally symmetrical metal rings. Each of the metal rings is composed of two straight metal strips and a bent metal strip. The ends of the two straight metal strips are connected to metal pads to form orthogonal feeding ports, which respectively excite horizontal polarization and vertical polarization. Figure 4 This is a schematic diagram of the second structure feed substrate 2 in the electrically small antenna based on the Rubik's Cube structure provided in this embodiment. Each of the two metal pads connecting the ends of the two straight metal strips of any metal ring has a metal via at the feed point. The radius of the metal pad is r3, and the radii of the metal vias at the feed point on the metal pads are r1 and r2, respectively.

[0057] In one embodiment, the isolation between the two metal rings of the doubly fed structure is greater than 38dB, and the 10dB bandwidth of the operating frequency band is not less than 5%.

[0058] In one embodiment, the substrate is made of Rogers 4003c material, with a relative permittivity of 3.38 and a tangent loss angle of 0.0027. The side length 'a' of the cube structure is 19-21 mm, the substrate thickness 't' is 0.8-0.9 mm, and the slot splicing length 'l' is 4-6 mm. Preferably, the side length 'a' of the cube structure is 20 mm, the substrate thickness 't' is 0.813 mm, and the slot splicing length 'l' is 5 mm. The overall dimensions of the substrate are a × a × t, and the slot dimensions are l × t × t.

[0059] In one embodiment, the microstrip width of the metal ring is 0.4 mm (w1) or 1.5 mm (w2), and the gap g of the bent metal strip is 4 mm.

[0060] In one embodiment, the electrical dimensions of the cube structure satisfy ka < 1, where k is the wave number, a is the minimum sphere radius surrounding the antenna, and the operating frequency band covers 1.21-1.22 GHz or 2.39-2.52 GHz.

[0061] The electrically small antenna based on the Rubik's Cube structure in the embodiment of the present invention was simulated using the software HFSS.

[0062] Table 1 shows the parameters of the electric small antenna based on the Rubik's Cube structure.

[0063] Table 1

[0064] parameter a t l <![CDATA[w1]]> <![CDATA[w2]]> g <![CDATA[r1]]> <![CDATA[r2]]> <![CDATA[r3 <!-- 5 -->]]> Size / mm 20 0.813 5 0.4 1.5 4 0.65 0.2 1

[0065] The first structure in this embodiment operates at 1.21-1.22 GHz, with a simulated 10 dB bandwidth of 0.8%. The highest simulated gain reaches 1.6 dBi. Figure 6 , Figure 7 and Figure 8 As shown.

[0066] The second architecture operates in the 2.39–2.52 GHz and 2.39–2.51 GHz bands, with simulated 10 dB bandwidths of 5.3% and 5%, respectively. Simulated maximum gains reach 2.8 dBi and 2.7 dBi, with isolation greater than 38 dB. Figure 9 , Figure 10 , Figure 11 , Figure 12 and Figure 13 As shown.

[0067] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A small electric antenna based on a Rubik's Cube structure, characterized in that, include: A metal ring structure formed by three-dimensional orthogonal folding; A cube structure is formed by splicing together at least three different types of substrates, with varying numbers of the three types of substrates; The metal ring structure is printed by microstrip lines on the six substrates of the cube-shaped structure; The metal ring structure excites a combination of multiple magnetic couplers and electric couples through single-feed or double-feed methods, thereby achieving omnidirectional radiation or dual-polarization functions with small electrical dimensions.

2. The electrically small antenna based on a Rubik's Cube structure according to claim 1, characterized in that, The substrate includes a first structure feeding substrate, a second structure feeding substrate, and a non-feeding substrate; The substrate has slots around its perimeter, and adjacent substrates are joined together by the slots.

3. The electrically small antenna based on a Rubik's Cube structure according to claim 2, characterized in that, The microstrip line of the metal ring structure is printed on the inner surface of the substrate, and the width of the microstrip line is adjusted according to the surface of the feeding substrate to achieve impedance matching.

4. The electrically small antenna based on a Rubik's Cube structure according to any one of claims 1-3, characterized in that, The single-feed structure includes a metal ring, which is formed by three-dimensional orthogonal folding of two straight metal strips and a bent metal strip. The ends of the two straight metal strips are connected to metal pads to excite a combination of multiple magnetic couples and electric couples to achieve 45-degree omnidirectional radiation.

5. The electrically small antenna based on a Rubik's Cube structure according to any one of claims 1-3, characterized in that, The doubly fed structure includes two orthogonally symmetrical metal rings. Each of the metal rings is composed of two straight metal strips and a bent metal strip. The ends of the two straight metal strips are connected to metal pads to form orthogonal feeding ports, which respectively excite horizontal polarization and vertical polarization.

6. The electrically small antenna based on a Rubik's Cube structure according to claim 5, characterized in that, The isolation between the two metal rings of the doubly fed structure is greater than 38dB, and the 10dB bandwidth of the operating frequency band is not less than 5%.

7. The electrically small antenna based on a Rubik's Cube structure according to claim 1, characterized in that, The substrate is made of Rogers 4003c, with a relative permittivity of 3.38 and a tangent loss angle of 0.0027. The side length 'a' of the cube structure is 19-21mm, the substrate thickness 't' is 0.8-0.9mm, and the slot splicing length is 4-6mm.

8. The electrically small antenna based on a Rubik's Cube structure according to claim 4 or 5, characterized in that, The microstrip width of the metal ring is 0.4 mm or 1.5 mm, and the gap g of the bent metal strip is 4 mm.

9. The electrically small antenna based on a Rubik's Cube structure according to claim 1, characterized in that, The electrical dimensions of the cube structure satisfy ka < 1, where k is the wave number, a is the minimum sphere radius surrounding the antenna, and the operating frequency band covers 1.21-1.22 GHz or 2.39-2.52 GHz.

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