A folded miniaturized broadband magneto-dipole antenna

Abstract

The application discloses a kind of miniaturization broadband magnetoelectric dipole antennas based on folding, it is related to wireless communication technical field.Antenna includes: L-shaped electric dipole, vertical folding short-circuit patch, Γ-shaped feed structure and U-shaped reflection cavity.L-shaped electric dipole top is connected with two vertical folding short-circuit patches with interval and constitutes radiation structure;Γ-shaped structure is coupled to radiation structure and is fed;U-shaped reflection cavity is located below, including horizontal reflection plate and vertical metal plate loaded on its edge.The application uses bending L-shaped electric dipole and folding short-circuit patch to greatly reduce the size of antenna, for the impedance mismatch caused by size reduction, using the vertical metal plate of edge loading and electric dipole form equivalent capacitive coupling, perfect impedance change is offset.The application reduces the volume of antenna by about 80%, widens the bandwidth to 119%, realizes the consideration of extremely miniaturization and broadband, and radiation characteristic is stable.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and more specifically to a miniaturized broadband magnetoelectric dipole antenna based on folding. Background Technology

[0002] The statements in this section are provided only as background information in connection with this disclosure and may not constitute prior art.

[0003] With the development of large-scale integrated circuit manufacturing technology, the size of electronic devices and circuit components is decreasing rapidly at a geometric rate, driving wireless communication devices towards miniaturization and micro-miniaturization. However, antennas, as a component of wireless communication systems, cannot keep pace with this miniaturization process in their traditional form, and their size often restricts the overall miniaturization of the system. Antenna performance is closely related to its structural size; reducing antenna size inevitably leads to a deterioration in performance indicators such as bandwidth, efficiency, and directivity. Therefore, achieving antenna miniaturization while maintaining broadband characteristics, while ensuring antenna performance meets basic application requirements, is of significant practical importance.

[0004] Magnetoelectric dipole antennas are a classic antenna type, possessing excellent performance characteristics such as wide operating bandwidth, stable radiation performance, low cross-polarization level, and weak backlobe radiation. However, according to the basic theory of magnetoelectric dipole antennas, this type of antenna typically includes a half-wavelength horizontal electric dipole, a pair of quarter-wavelength vertical short-circuit patches acting as magnetic dipoles, and a large-sized reflector or reflective cavity. This results in a generally large structural size, severely limiting its practical applications. Therefore, exploring and designing miniaturized magnetoelectric dipole antennas with compact dimensions has significant application value. Summary of the Invention

[0005] The purpose of this invention is to address the problems of large structural size of traditional magnetoelectric dipole antennas and the impedance mismatch, narrowing bandwidth, and deterioration of radiation performance caused by bending or size reduction in existing miniaturization designs. This invention provides a miniaturized broadband magnetoelectric dipole antenna based on folding. Based on the design scheme of bending the horizontal electric dipole into an L-shape, folding the short-circuit patch inward vertically, and loading a vertical metal plate on the edge of the reduced-size horizontal reflector to form a U-shaped reflector cavity, the antenna size is significantly reduced (volume reduction of about 80%). The equivalent capacitive coupling formed between the vertical metal plate and the L-shaped electric dipole perfectly cancels the impedance mismatch caused by antenna folding and reflector reduction, thus maintaining and widening the antenna bandwidth while achieving extreme miniaturization.

[0006] The technical solution of the present invention is as follows: A miniaturized broadband magnetoelectric dipole antenna based on folding, comprising: L-shaped electric dipole, vertically folded short-circuit patch, Γ-shaped feed structure and U-shaped reflective cavity; Two vertically folded short-circuit patches are provided, and there is a certain interval between the two vertically folded short-circuit patches; The top of the L-shaped electric dipole is connected to the upper ends of the two vertically folded short-circuit patches, together forming an antenna radiation structure; The Γ-shaped feed structure is located at the interval between the two vertically folded short-circuit patches to couple and feed the antenna radiation structure. The U-shaped reflective cavity is located below the L-shaped electric dipole; the U-shaped reflective cavity includes a horizontal reflector and a vertical metal plate loaded on the edge of the horizontal reflector.

[0007] Furthermore, the L-shaped electric dipole includes a horizontal trapezoidal portion and a vertical rectangular portion; the horizontal trapezoidal portion is bent and extended to form the vertical rectangular portion.

[0008] Furthermore, there are two vertical metal plates, which are symmetrically loaded on opposite sides of the horizontal reflector; the horizontal reflector and the two vertical metal plates together form a U-shaped cavity structure with a top opening.

[0009] Furthermore, the vertical metal plate is grounded, and there is a preset gap between the top edge of the vertical metal plate and the L-shaped electric dipole, so that capacitive coupling is formed between the vertical metal plate and the L-shaped electric dipole.

[0010] Furthermore, the Γ-shaped feed structure includes a transmission line section, a coupling section, and an impedance adjustment section; One end of the transmission line section is used to connect to an external coaxial power supply structure, and the other end is connected to the coupling section; the end of the coupling section away from the transmission line section is connected to the impedance adjustment section.

[0011] Furthermore, a fixed gap is maintained between the transmission line portion and the sidewall of one of the vertically folded short-circuit patches to form a microstrip transmission line with air as the medium.

[0012] Furthermore, the coupling portion is horizontally positioned to couple energy to the antenna radiation structure; the impedance adjustment portion is positioned vertically and employs a stepped bending structure.

[0013] Furthermore, the vertically folded short-circuit patch is a folded structure that is bent along the vertical direction to form a bent portion; the bottom end of the vertically folded short-circuit patch is shorted to the horizontal reflector.

[0014] Furthermore, the bent portions of the two vertically folded short-circuit patches extend horizontally toward each other, and the gap is formed between the end faces of the two bent portions.

[0015] Furthermore, the L-shaped electric dipole, the vertically folded short-circuit patch, and the U-shaped reflective cavity are all aluminum components of the same thickness; the Γ-shaped feeding structure is a copper component, and the thickness of the Γ-shaped feeding structure is less than the thickness of the L-shaped electric dipole.

[0016] Compared with existing technologies, the advantages of this invention are: 1. Extreme Miniaturization Design: This invention achieves this by bending and folding the antenna structure in both horizontal and vertical dimensions (the horizontal electric dipole is bent into an L-shape, and the vertical short-circuit patch is folded inward), and significantly reducing the size of the reflector, thus reducing the overall size of the antenna from the traditional... Reduce to The size has been reduced by about 80%, which greatly saves the space occupied by the antenna.

[0017] 2. Excellent Impedance Matching and Broadband Characteristics: This invention innovatively employs a loading of a vertical metal plate to construct a U-shaped reflective cavity. Utilizing the coupling effect generated by the preset gap (equivalent to capacitance) between the grounded vertical metal plate (equivalent to an inductor) and the radiating element, the impedance mismatch caused by bending and reduced reflector size is effectively offset. Better impedance matching is achieved in the low-frequency band, increasing the antenna bandwidth from 109% (1.25~4.1 GHz) to 119% (1~3.98 GHz), thus achieving broadband in reverse.

[0018] 3. Stable radiation performance: While achieving miniaturization and broadband, the antenna of the present invention has stable radiation characteristics within the operating frequency band, and the gain within the operating frequency band remains in a stable range (approximately 4.3±1.1 dBi), which fully meets the transmission requirements of broadband microwave wireless communication systems for high-quality signals. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in the embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0020] Figure 1 A schematic diagram of the overall antenna structure provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the antenna structure provided in an embodiment of the present invention; Figure 3A side view of the antenna structure provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the antenna feeding structure provided in an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the antenna design evolution process provided in an embodiment of the present invention; Figure 6 The graphs showing the variation of VSWR and gain for different antennas provided in the embodiments of the present invention; Figure 7 A graph showing the effect of the height of the vertical metal plate on the real part of the input impedance, provided for an embodiment of the present invention. Figure 8 A graph showing the effect of the height of the vertical metal plate on the imaginary part of the input impedance, provided for an embodiment of the present invention. Figure 9 A graph showing the effect of the height of the vertical metal plate on the antenna standing wave ratio (VSWR) provided in an embodiment of the present invention.

[0021] Figure label: 1-L-shaped electric dipole; 101-Horizontal trapezoidal portion; 102-Vertical rectangular portion; 2-Vertical folded short-circuit patch; 3-Γ-shaped power supply structure; 4-U-shaped reflective cavity; 401-Horizontal reflective plate; 402-Vertical metal plate. Detailed Implementation

[0022] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0023] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0024] Example 1 To address the issues of large structural size in existing magnetoelectric dipole antennas, and the narrowing bandwidth and degraded radiation performance in current miniaturization designs, this embodiment provides a miniaturized broadband magnetoelectric dipole antenna based on folding. For example... Figure 1Schematic diagram of the overall antenna structure Figure 2 Antenna structure diagram and Figure 3 The antenna structure is shown in the side view. The specific structure and working principle of the antenna are as follows: The antenna includes: an L-shaped electric dipole 1, a vertically folded short-circuit patch 2, a Γ-shaped feed structure 3, and a U-shaped reflector 4. Two vertically folded short-circuit patches 2 are provided, with a certain interval between them, preferably of the following size. The top of the L-shaped electric dipole 1 is connected to the upper ends of the two vertically folded short-circuit patches 2, together forming the antenna radiation structure. A Γ-shaped feed structure 3 is located at the interval between the two vertically folded short-circuit patches 2 to couple and feed the antenna radiation structure. The U-shaped reflector 4 is located below the horizontal portion of the L-shaped electric dipole 1, and the preferred distance between them is... The U-shaped reflector 4 includes a horizontal reflector 401 and a vertical metal plate 402 loaded on the edge of the horizontal reflector 401. This infrastructure, by introducing the U-shaped reflector 4, aims to improve impedance matching performance and enhance the unidirectional radiation characteristics of the antenna.

[0025] Furthermore, the L-shaped electric dipole 1 includes a horizontal trapezoidal portion 101 and a vertical rectangular portion 102; the horizontal trapezoidal portion 101 is bent and extended to form the vertical rectangular portion 102. In the horizontal direction, to achieve miniaturization, a conventional half-wavelength horizontal electric dipole is bent into an L-shape while maintaining the total length. The trapezoidal portion 101 helps to extend the current path and expand the bandwidth, and the dimensions of its bent horizontal portion are preferably... The preferred size of the folded portion Through this bending design, the horizontal length of the electric dipole was reduced from 93mm to 66mm, a reduction of 27mm, achieving miniaturization in the horizontal dimension while maintaining the overall path length uniformity.

[0026] Regarding the specific structure of the U-shaped reflective cavity 4, two vertical metal plates 402 are provided. The two vertical metal plates 402 are symmetrically loaded on opposite sides of the horizontal reflector 401, so that the horizontal reflector 401 and the two vertical metal plates 402 together form a U-shaped cavity structure with an open top. The vertical metal plates 402 are grounded, and there is a preset gap between the top edge of the vertical metal plates 402 and the L-shaped electric dipole 1, so that capacitive coupling is formed between the vertical metal plates 402 and the L-shaped electric dipole 1.

[0027] This design is the core solution to address impedance mismatch. To achieve overall horizontal miniaturization, the antenna uses a smaller reflector instead of a larger one (the preferred side length of the horizontal reflector 401 is...). (Only slightly larger than the size of the radiating element). The bending in both the vertical and horizontal dimensions, along with the reduction in the reflector size, degrades the antenna impedance matching performance within the operating frequency band. To allow adjustment without changing the reduced reflector size, vertical metal plates 402 are loaded on both sides of the horizontal reflector 401. The width of the vertical metal plates 402 is preferably... The preferred height .

[0028] From a mechanistic perspective, the grounded vertical metal plate 402 can be considered an inductor, while the gap between the vertical metal plate 402 and the L-shaped electric dipole 1 can be equivalent to a capacitor. By adjusting the dimensions of the vertical metal plate 402, the LC coupling between them can be adjusted, perfectly offsetting the input impedance changes caused by bending the horizontal electric dipole and reducing the size of the reflector. Figure 7 The effect of the height of the vertical metal plate on the real part of the input impedance and Figure 8 As can be seen from the effect of the height of the vertical metal plate on the imaginary part of the input impedance, as the height of the vertical metal plate increases... As the input impedance increases, the imaginary part of the low-frequency band flattens out and gradually approaches zero; while the real part flattens out and approaches 50Ω, gradually shifting towards lower frequencies. This indicates that the introduction of the vertical metal plate enables the antenna to achieve better impedance matching in the low-frequency band, and the low-frequency cutoff frequency gradually shifts down from 1.4GHz to 1GHz, while the high-frequency cutoff frequency remains basically unchanged, further realizing the miniaturization and broadband design of the antenna.

[0029] Furthermore, such as Figure 4 As shown in the schematic diagram of the antenna feed structure, the Γ-shaped feed structure 3 includes a transmission line section, a coupling section, and an impedance adjustment section. One end of the transmission line section is used to connect to an external coaxial feed structure, and the other end is connected to the coupling section; the end of the coupling section away from the transmission line section is connected to the impedance adjustment section. A fixed gap is maintained between the transmission line section and the sidewall of one of the vertically folded short-circuit patches 2, forming a microstrip transmission line with air as the medium. The coupling section is horizontally positioned to couple energy to excite the antenna's radiating elements; the impedance adjustment section is positioned vertically and adopts a stepped bending structure. By adjusting its length variation, good impedance matching characteristics are obtained over a wide frequency band. The preferred structural parameters are: , , , , , .

[0030] For the vertical dimension structure, the vertically folded short-circuit patch 2 is a folded structure that bends along the vertical direction to form a bent portion, reducing the height; the bottom end of the vertically folded short-circuit patch 2 is shorted to the horizontal reflector 401. The bent portions of the two vertically folded short-circuit patches 2 extend horizontally towards each other, and the gap is formed between the end faces of the two bent portions. .

[0031] In this embodiment, a pair of vertically folded patches replace the traditional vertically erected quarter-wavelength short-circuit patches and are shorted to the horizontal reflector 401 to serve as the magnetic dipole portion of the antenna. The horizontal length of the folded portion is preferably... The preferred height This folding method maintains the same overall length, but reduces the vertical section height from 44mm to [missing value]. This reduces the size by 9mm, enabling miniaturization of the antenna in the vertical dimension.

[0032] In terms of manufacturing materials, the L-shaped electric dipole 1, the vertically folded short-circuit patch 2, and the U-shaped reflective cavity 4 are all aluminum parts of the same thickness, preferably made of aluminum plate with a thickness of 0.5mm by welding; the Γ-shaped feeding structure 3 is a copper part, and its thickness is less than that of the L-shaped electric dipole 1, preferably made of copper plate with a thickness of 0.2mm.

[0033] To clearly understand the research and development process of this invention and the effectiveness of the above design, combined with Figure 5 Antenna design process and Figure 6 The variations in VSWR and gain for different antennas are explained below: The first step involved designing a broadband magnetoelectric dipole antenna (antenna 1) based on fundamental principles. The antenna employs an unbent trapezoidal electric dipole (93mm long) in the horizontal direction and a pair of folded short-circuit patches in the vertical direction, along with a 140mm × 140mm horizontal reflector. After optimization, the overall dimensions of antenna 1 are 140mm × 140mm × 30mm (approximately...). The operating frequency can cover 1.2~4.1 GHz and the voltage standing wave ratio (VSWR) is <2, with a corresponding relative bandwidth of 109%.

[0034] The second step is to reduce the size of the horizontal electric dipole (antenna 2). The horizontal length of the electric dipole is reduced from 93mm to 66mm by bending. At this time, the low-frequency cutoff frequency of the operating band of antenna 2 shifts slightly upward, the impedance matching within the operating band deteriorates, the gain fluctuation range increases, and the instability of the radiation characteristics increases.

[0035] The third step is to reduce the size of the horizontal reflector (antenna 3). The reflector is directly reduced to 75mm × 75mm, while other parameters remain unchanged. This operation meets the antenna's miniaturization design requirements. However, if... Figure 6 As shown, after the size of the reflector is reduced, the impedance matching in the operating frequency band deteriorates further, the VSWR fluctuations become larger, and some values ​​are greater than 2.

[0036] Fourthly, to improve impedance mismatch, a vertical metal plate is loaded onto the edge of the reduced-size reflector to form a U-shaped reflective cavity (antenna 4, i.e., the final solution in this embodiment). Capacitive and inductive coupling are adjusted by modifying the metal plate. Figure 9 The effect of the height of the vertical metal plate on the antenna's VSWR is shown. Compared with the traditional antenna 1, the VSWR curves of antenna 4 with the vertical metal plate almost completely overlap in the mid-to-high frequency band, and both exhibit almost identical impedance matching characteristics. At the same time, the range of gain variation within the frequency band decreases and tends to stabilize.

[0037] In summary, the final overall size of this embodiment is reduced to 75mm × 75mm × 30mm (i.e. Compared to traditional low-profile magnetoelectric dipole antennas, this invention reduces the size by approximately 80%. Simultaneously, the antenna bandwidth is increased from 109% (1.25~4.1 GHz) to 119% (1~3.98 GHz). The antenna exhibits stable radiation characteristics, with a gain of approximately 4.3±1.1 dBi within the operating band. This invention achieves miniaturization while maintaining and broadening broadband characteristics through a clever equivalent LC coupling cancellation mechanism, yielding remarkably significant benefits.

[0038] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

[0039] This background section is provided to generally present the context of the invention. The work of the currently named inventors, the work to the extent described in this background section, and aspects of this section that did not constitute prior art at the time of application are neither expressly nor impliedly acknowledged as prior art to the invention.

Claims

1. A miniaturized broadband magnetoelectric dipole antenna based on folding, characterized in that, include: L-shaped electric dipole (1), vertically folded short-circuit patch (2), Γ-shaped feeding structure (3) and U-shaped reflective cavity (4); Two vertically folded short-circuit patches (2) are provided, and there is a gap between the two vertically folded short-circuit patches (2); The top of the L-shaped electric dipole (1) is connected to the upper ends of the two vertically folded short-circuit patches (2), together forming an antenna radiation structure; The Γ-shaped feed structure (3) is located at the interval between the two vertically folded short-circuit patches (2) to couple the feed to the antenna radiation structure; The U-shaped reflective cavity (4) is located below the L-shaped electric dipole (1); the U-shaped reflective cavity (4) includes a horizontal reflector (401) and a vertical metal plate (402) loaded on the edge of the horizontal reflector (401).

2. The miniaturized broadband magnetoelectric dipole antenna based on folding according to claim 1, characterized in that, The L-shaped electric dipole (1) includes a horizontal trapezoidal portion (101) and a vertical rectangular portion (102); the horizontal trapezoidal portion (101) is bent and extended to form the vertical rectangular portion (102).

3. The miniaturized broadband magnetoelectric dipole antenna based on folding according to claim 1, characterized in that, Two vertical metal plates (402) are provided, and the two vertical metal plates (402) are symmetrically loaded on opposite sides of the horizontal reflector (401); the horizontal reflector (401) and the two vertical metal plates (402) together form a U-shaped cavity structure with an open top.

4. The miniaturized broadband magnetoelectric dipole antenna based on folding according to claim 3, characterized in that, The vertical metal plate (402) is grounded, and there is a preset gap between the top edge of the vertical metal plate (402) and the L-shaped electric dipole (1) so that capacitive coupling is formed between the vertical metal plate (402) and the L-shaped electric dipole (1).

5. The miniaturized broadband magnetoelectric dipole antenna based on folding according to claim 1, characterized in that, The Γ-shaped power supply structure (3) includes a transmission line section, a coupling section, and an impedance adjustment section; One end of the transmission line section is used to connect to an external coaxial feed structure, and the other end is used to connect to the coupling section; The end of the coupling section away from the transmission line section is connected to the impedance adjustment section.

6. The miniaturized broadband magnetoelectric dipole antenna based on folding according to claim 5, characterized in that, The transmission line portion maintains a fixed gap with the sidewall of one of the vertically folded short-circuit patches (2) to form a microstrip transmission line with air as the medium.

7. The miniaturized broadband magnetoelectric dipole antenna based on folding according to claim 5, characterized in that, The coupling portion is horizontally positioned to couple energy to the antenna radiation structure; the impedance adjustment portion is positioned vertically and employs a stepped bending structure.

8. The miniaturized broadband magnetoelectric dipole antenna based on folding according to claim 1, characterized in that, The vertically folded short-circuit patch (2) is a folded structure that is bent in the vertical direction to form a bent portion; the bottom end of the vertically folded short-circuit patch (2) is short-circuited with the horizontal reflector (401).

9. The miniaturized broadband magnetoelectric dipole antenna based on folding according to claim 8, characterized in that, The bent portions of the two vertically folded short-circuit patches (2) extend horizontally toward each other, and the gap is formed between the end faces of the two bent portions.

10. The miniaturized broadband magnetoelectric dipole antenna based on folding according to any one of claims 1 to 9, characterized in that, The L-shaped electric dipole (1), the vertically folded short-circuit patch (2), and the U-shaped reflective cavity (4) are all aluminum parts with the same thickness; the Γ-shaped feeding structure (3) is a copper part, and the thickness of the Γ-shaped feeding structure (3) is less than the thickness of the L-shaped electric dipole (1).

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