I-shaped slot radiation antenna based on electromagnetic metamaterial design
By introducing electromagnetic metamaterial structures and I-shaped slots within a rectangular waveguide, the problem of narrow bandwidth in rectangular waveguide slot antennas was solved, achieving efficient unidirectional transmission and improved radiation efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-22
- Publication Date
- 2026-04-07
AI Technical Summary
Existing rectangular waveguide slot antennas have narrow bandwidths, making them difficult to adapt to multi-band communication requirements, and their radiation efficiency and gain are also low.
Design an I-shaped slotted radiating antenna based on electromagnetic metamaterials. By setting an electromagnetic metamaterial structure and an I-shaped slot in a rectangular waveguide, unidirectional transmission is achieved, the operating bandwidth is widened, and the radiation efficiency and gain are improved.
It achieves high unidirectional transmission efficiency, exceeding 99%, and reverse transmission efficiency below 2%. At the same time, it widens the operating bandwidth, reduces the standing wave ratio, and improves radiation efficiency and gain.
Smart Images
Figure CN121812943A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of rectangular waveguide slot antenna technology, and more specifically, to an I-shaped slot radiating antenna based on electromagnetic metamaterial design. Background Technology
[0002] Rectangular waveguide slot antennas utilize slots in the waveguide walls to disrupt the original current distribution, enabling electromagnetic radiation and reception. Typically, rectangular waveguides primarily transmit TE10 mode electromagnetic waves, creating specific induced currents along their wide and narrow sides. When slots are created in the waveguide walls, and the slot direction is not parallel to the current flow direction, the current path is interrupted, forcing some electromagnetic energy to radiate from the slots into free space.
[0003] By designing the location, size, and arrangement of the slots, the phase, direction, and gain of the radiation can be controlled. Array-type slots can also achieve directional radiation characteristics such as narrow beams and low sidelobes through beamforming.
[0004] However, existing rectangular waveguide slot antennas have certain performance limitations, including narrow bandwidth, making them unsuitable for multi-band communication needs. Due to the resonant radiation mechanism of the rectangular waveguide slot antenna and the inherent transmission characteristics of the waveguide, deviations in the manufacturing output of parameters such as the slot position, size, and waveguide wall thickness can affect the resonant length and radiation performance. This results in a large standing wave ratio, low radiation efficiency, and low gain at the corresponding frequency points. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide an I-shaped slot radiating antenna based on electromagnetic metamaterial design. The introduction of electromagnetic metamaterial enables unidirectional transmission, and the combination of I-shaped slot will improve the operating bandwidth, radiation efficiency and gain of the rectangular waveguide slot antenna, and reduce the standing wave ratio. The solution adopted by this invention to solve the technical problem is: An I-shaped slotted radiating antenna based on electromagnetic metamaterial design includes a rectangular waveguide with a cavity, electromagnetic metamaterial structures disposed within the cavity and symmetrically arranged axially along the length of the rectangular waveguide, and an I-shaped slot disposed on the upper surface of the rectangular waveguide and connected to the cavity; the thickness of the two sets of electromagnetic metamaterial structures increases axially along the length of the rectangular waveguide; the I-shaped slot is disposed on the side of the metal short surface near the rectangular waveguide.
[0006] In some possible implementations, the two sets of electromagnetic metamaterial structures are positioned close to each other to form a cavity that communicates with the cavity.
[0007] In some possible implementations, the thickness of the electromagnetic metamaterial structure increases in a binomial polynomial gradient along the length of the rectangular waveguide, forming a focusing region of electric field capability on the electromagnetic metamaterial.
[0008] In some possible implementations, the cross-section of the cavity is an isosceles trapezoid; the large end and small end of the cavity are arranged parallel to the waveport and metal short surface of the rectangular waveguide.
[0009] In some possible implementations, the dielectric constant of the electromagnetic metamaterial structure is 4-50, and the magnetic permeability is 1.
[0010] In some possible implementations, the I-shaped slot includes two sets of rectangular slots symmetrically arranged on the upper surface of the rectangular waveguide along the long side direction, and an intermediate slot arranged on the upper surface of the rectangular waveguide and communicating with the two sets of rectangular slots.
[0011] In some possible implementations, the rectangular slit is positioned above the electromagnetic metamaterial structure with its long side parallel to the long side of the rectangular waveguide.
[0012] In some possible implementations, the long side of the rectangular slit is arranged along the long side of the rectangular waveguide, and the rectangular slit is positioned directly above the electric field energy focusing region corresponding to the electromagnetic metamaterial structure.
[0013] In some possible implementations, the thickness of the electromagnetic metamaterial structure increases in a linear, periodic, exponential, logarithmic, or step gradient along the length of the rectangular waveguide.
[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention maintains a fixed dielectric constant for the electromagnetic metamaterial and increases its thickness in a gradient along the long side axis of the rectangular waveguide. This fixed dielectric constant facilitates fabrication. Combined with the electromagnetic metamaterial, unidirectional transmission is achieved, with a forward transmission efficiency exceeding 99% and a reverse transmission efficiency of less than 2%, consistent with the characteristics of unidirectional transmission devices. Furthermore, the presence of an I-shaped slot on the upper surface of the rectangular waveguide effectively widens the operating bandwidth, reduces the standing wave ratio, and improves radiation efficiency and gain. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram showing the positional relationship between the rectangular waveguide, the electromagnetic metamaterial structure, and the I-shaped slit in this invention; Figure 3 This is a schematic diagram of the forward propagation of electromagnetic waves in Example 1; Figure 4 This is a schematic diagram of the reverse propagation of electromagnetic waves in Example 2; Figure 5 This is a diagram showing the electric field distribution of the I-shaped gap in this invention. Figure 6 The diagram shows the power reflection coefficient of the I-shaped slot antenna in Example 3; Figure 7 The gain pattern of the I-shaped slot waveguide in Example 3; Figure 8 The electric field distribution diagram of the I-shaped gap in Comparative Example 1; Figure 9 The diagram shows the power reflection coefficient of the I-shaped slot antenna in Comparative Example 1. Figure 10 The gain pattern of the I-shaped slot antenna is shown in Comparative Example 1. Figure 11 This is a schematic diagram of electromagnetic wave reflection within a rectangular waveguide. Among them: 1. Rectangular waveguide; 10. Cavity; 2. Electromagnetic metamaterial structure; 3. I-shaped slit; 31. Rectangular slit; 32. Intermediate slit. Detailed Implementation
[0016] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, "a" or "one," etc., do not indicate a quantity limitation, but rather indicate the existence of at least one. In the implementation of this application, "and / or" describes the association relationship of related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more. For example, multiple positioning posts refer to two or more positioning posts. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0017] The present invention will now be described in detail.
[0018] like Figures 1-11 As shown: An I-shaped slot 3 radiating antenna based on electromagnetic metamaterial design includes a rectangular waveguide 1 with a cavity 10, electromagnetic metamaterial structures 2 disposed within the cavity 10 and symmetrically arranged along the length direction of the rectangular waveguide 1, and an I-shaped slot 3 disposed on the upper surface of the rectangular waveguide 1 and connected to the cavity 10; the thickness of the two sets of electromagnetic metamaterial structures 2 increases axially along the length direction of the rectangular waveguide 1; the I-shaped slot 3 is disposed on the side of the metal short surface near the rectangular waveguide 1; the two sets of electromagnetic metamaterial structures 2 are close to each other to form a cavity connected to the cavity 10.
[0019] This invention introduces an electromagnetic metamaterial into a rectangular waveguide 1 to construct an asymmetric electromagnetic environment based on specific dielectric constant characteristics. It utilizes the coupling of positive and negative electromagnetic waves with the metamaterial and the difference in mode adaptation to form non-reciprocal transmission. By constructing the electromagnetic metamaterial, the reciprocity of transmission is broken. The positive and negative coupling and the difference in mode adaptation lead to transmission differentiation. By designing the structure and material gradient parameters of the electromagnetic metamaterial, the operating frequency band of unidirectional transmission can be effectively determined. By symmetrically arranging two sets of electromagnetic metamaterial structures 2 along the length of the rectangular waveguide 1, with the thickness of the two sets of electromagnetic metamaterial structures 2 increasing axially along the length of the rectangular waveguide 1, and setting the dielectric constant of the electromagnetic metamaterial structures 2 to a fixed value, the rectangular waveguide 1 can achieve unidirectional transmission, which conforms to the characteristics of unidirectional transmission devices. At the same time, since an I-shaped slot 3 is set on the upper surface of the rectangular waveguide 1 to connect with the cavity 10, the slot branch of the I-shaped slot 3 will be equivalent to multi-element coordinated radiation. Through cooperation with the electromagnetic metamaterial structure 2, the problem of antenna standing wave ratio deterioration can be avoided, the operating bandwidth can be widened, the standing wave ratio can be reduced, and the radiation efficiency and gain can be improved.
[0020] By setting up the aforementioned electromagnetic metamaterial, the equivalent relative permittivity inside the rectangular waveguide 1 will increase, and the electric field energy will be focused within the electromagnetic metamaterial. Compared with the traditional rectangular waveguide 1 with slots, setting up the I-shaped slot 3 will cut the current on both the wide side and the axial direction of the rectangular waveguide 1. Since the I-shaped slot 3 waveguide antenna has a larger current-cutting area, and the slot branches can be equivalent to multi-element coordinated radiation, it can compress the beamwidth, improve the gain of directional radiation, and have higher radiation efficiency.
[0021] In some possible implementations, the thickness of the electromagnetic metamaterial structure 2 increases in a binomial polynomial gradient along the length of the rectangular waveguide 1, forming a focusing region of electric field capability within the electromagnetic metamaterial.
[0022] When the thickness of the electromagnetic metamaterial structure 2 increases in a binomial polynomial gradient, the cross-section of the cavity is an isosceles trapezoid; the large end and small end of the cavity are arranged parallel to the wave port and the metal short surface of the rectangular waveguide 1; the metal short surface is the surface of the rectangular waveguide 1 opposite to the wave port.
[0023] In some possible implementations, the dielectric constant of the electromagnetic metamaterial structure 2 is 4-50, and the magnetic permeability is 1.
[0024] In some possible implementations, the I-shaped slot 3 includes two sets of rectangular slots 31 symmetrically arranged on the upper surface of the rectangular waveguide 1 along the long side of the rectangular waveguide 1, and an intermediate slot 32 arranged on the upper surface of the rectangular waveguide 1 and communicating with the two sets of rectangular slots 31; the rectangular slots 31 are arranged above the electromagnetic metamaterial structure 2 and their long sides are parallel to the long side of the rectangular waveguide 1; the long side of the rectangular slots 31 is arranged along the long side of the rectangular waveguide 1, and the rectangular slots 31 are located directly above the electric field energy focusing region corresponding to the electromagnetic metamaterial structure 2.
[0025] As the thickness of the electromagnetic metamaterial increases along the long side of the rectangular waveguide 1, i.e. the equivalent relative permittivity inside the rectangular waveguide 1 increases, the electric field energy is focused near the electromagnetic metamaterial. By designing the upper and lower wide sides of the "I"-shaped antenna to be in the electric field energy focusing region, greater radiation efficiency, lower VSWR and higher antenna gain can be achieved.
[0026] This invention combines electromagnetic metamaterial technology with an I-shaped slot 3 antenna, requiring that the upper and lower wide sides of the I-shaped slot 3 antenna be located within the horizontal cross-section of the electromagnetic metamaterial.
[0027] In some possible implementations, in order to effectively achieve the axial increase of the thickness of the electromagnetic metamaterial structure 2 along the length direction of the rectangular waveguide 1, the thickness of the electromagnetic metamaterial structure 2 increases in a linear, periodic, exponential, logarithmic, or step manner along the axial direction of the length direction of the rectangular waveguide 1.
[0028] Example 1: like Figures 1-2 , Figure 3 , Figure 11 As shown: In this embodiment, rectangular waveguide 1 is a BJ22 rectangular waveguide 1, which is capable of propagating TE. 10 Single-mode cavity TE mode of electromagnetic waves 10 The single-mode operating frequency is 1.75-2.61 GHz; the standing wave ratio is less than 2; the dielectric constant of electromagnetic metamaterial structure 2 is 20, and the permeability is 1. For the design of electromagnetic metamaterials, assume there exists a pair of plane waves bouncing up and down, propagating obliquely upwards from the +x and -x directions shown in the figure, respectively. In this case, no electromagnetic metamaterial is introduced inside the rectangular waveguide 1. The two electromagnetic waves follow the traditional law of reflection, i.e., at the metallic boundary, the angle of incidence equals the angle of reflection, as shown below. Figure 11As shown by the dashed lines in the diagram, (a) represents forward transmission and (b) represents reverse transmission; when an electromagnetic metamaterial is introduced inside the rectangular waveguide 1, the electromagnetic wave will no longer follow the traditional law of reflection. When the refractive index of an electromagnetic metamaterial varies with the x-axis, the electromagnetic wave exhibits a phase gradient along the x-axis. The behavior of the reflected wave in this case is as follows: Figure 11 As shown in the figure; Assuming that the refractive index of the metamaterial increases with the +x axis gradient, when an electromagnetic wave is fed in from the left side of rectangular waveguide 1, once it propagates to the electromagnetic metamaterial interface, the reflection angle will be greater than the incident angle; while when the electromagnetic wave is fed in from the right side of rectangular waveguide 1, the reflection angle will be smaller than the incident angle. Based on this, after multiple reflections, an asymmetric propagation phenomenon will be exhibited, thus constructing an asymmetric electromagnetic environment. exist Figure 11 In this embodiment, the thickness of the electromagnetic metamaterial structure remains constant along the x-axis, meaning the thickness of the internal filling medium (air) also remains constant along the x-axis. By using the equivalent theory of dielectric constant, keeping the metamaterial's dielectric constant constant and controlling the ratio of the electromagnetic metamaterial structure's thickness to the air thickness is equivalent to achieving a change in the dielectric constant along the x-axis. Therefore, in this embodiment, the thickness of the electromagnetic metamaterial structure 2 is set to increase in a binomial polynomial gradient along the length of the rectangular waveguide 1, such as... Figure 2 As shown.
[0029] Based on the above setup, the end of the rectangular waveguide 1 closest to the large end of the cavity is designated as the waveport, and the side furthest from the waveport is designated as a short-circuit metal surface. Simulation analysis was used to obtain the electric field distribution within the rectangular waveguide 1, as follows: Figure 3 As shown, the power reflection coefficient S11 = -23.757dB, which means that the transmission efficiency exceeds 99%.
[0030] Example 2: Based on Embodiment 1, one end of the rectangular waveguide 1 near the small end of the cavity is designated as the waveport, and the other end is designated as the absorbing boundary condition. The electric field distribution within the rectangular waveguide 1 is analyzed through simulation. Figure 4 As shown, S11 = -0.078362dB, which means that the transmission efficiency is less than 2%.
[0031] Example 3: Based on Example 1, the end of the rectangular waveguide 1 closest to the large end of the cavity is designated as the waveport. One side of the waveport is a metallic short-circuit surface, which is a perfect electrical conductor boundary condition. The electric field distribution is analyzed through simulation, as shown below. Figure 5 As shown, it is clear that as the thickness of the electromagnetic metamaterial increases, the electric field is mainly focused within the metamaterial.
[0032] Power reflection coefficient |S11| as Figure 6As shown, within the 1.75-2.61GHz range, the power reflection coefficient |S11| is less than -10dB, and the standing wave ratio is less than 2 across the entire frequency band. Figure 7 The image shows the gain pattern of the I-shaped slot 3-waveguide, with a maximum gain of 8.4 dBi.
[0033] Comparative Example 1: Based on Embodiment 1, the end of the rectangular waveguide 1 near the large end of the cavity is set as the waveport, and one side of the waveport is a short-circuit metal surface. The dielectric constant of the electromagnetic metamaterial is changed from 20 to 1, at which point the electromagnetic metamaterial is equivalent to air; the electric field distribution diagram is as follows. Figure 8 As shown, the electric field is no longer focused in the material with a gradually varying thickness; the power reflection coefficient |S11| is as follows. Figure 9 As shown, within the 1.75-2.61GHz range, the power reflection coefficient |S11| is greater than -10dB, and the standing wave ratio is greater than 2 across the entire frequency band. Figure 10 The image shows the gain pattern of the I-shaped slot 3-waveguide, with a maximum gain of 6.4 dBi.
[0034] Compared to existing technologies, this invention achieves simultaneous horizontal and wide-side cutting of current through the I-shaped slit 3, thereby radiating electromagnetic waves. The electromagnetic metamaterial structure 2 designed in this invention, a unidirectional transmission waveguide, concentrates electric field energy primarily within the metamaterial as its thickness increases. The I-shaped slit 3 allows for more efficient electromagnetic wave radiation while simultaneously improving the gain of directional radiation.
[0035] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.
Claims
1. An I-shaped slotted radiating antenna based on electromagnetic metamaterials, characterized in that, It includes a rectangular waveguide with a cavity, an electromagnetic metamaterial structure disposed within the cavity and symmetrically arranged along the length of the rectangular waveguide, and an I-shaped slot disposed on the upper surface of the rectangular waveguide and connected to the cavity; the thickness of the two sets of electromagnetic metamaterial structures increases axially along the length of the rectangular waveguide; the I-shaped slot is disposed on the side of the metal short surface near the rectangular waveguide.
2. The I-shaped slotted radiating antenna based on electromagnetic metamaterial design according to claim 1, characterized in that, The two sets of electromagnetic metamaterial structures are close to each other on one side to form a cavity that is connected to the air cavity.
3. The I-shaped slotted radiating antenna based on electromagnetic metamaterial design according to claim 2, characterized in that, The thickness of the electromagnetic metamaterial structure increases in a binomial polynomial gradient along the length of the rectangular waveguide, forming a focusing region of electric field capability within the electromagnetic metamaterial.
4. The I-shaped slotted radiating antenna based on electromagnetic metamaterial design according to claim 3, characterized in that, The cross-section of the cavity is an isosceles trapezoid; the large end and small end of the cavity are arranged parallel to the wave port and metal short surface of the rectangular waveguide.
5. The I-shaped slotted radiating antenna based on electromagnetic metamaterial design according to claim 1, characterized in that, The dielectric constant of the electromagnetic metamaterial structure is 4-50, and the magnetic permeability is 1.
6. The I-shaped slotted radiating antenna based on electromagnetic metamaterial design according to claim 1, characterized in that, The I-shaped slot includes two sets of rectangular slots symmetrically arranged on the upper surface of the rectangular waveguide along the long side direction, and an intermediate slot arranged on the upper surface of the rectangular waveguide and connected to the two sets of rectangular slots.
7. The I-shaped slotted radiating antenna based on electromagnetic metamaterial design according to claim 6, characterized in that, The rectangular slit is positioned above the electromagnetic metamaterial structure, with its long side parallel to the long side of the rectangular waveguide.
8. The I-shaped slotted radiating antenna based on electromagnetic metamaterial design according to claim 7, characterized in that, The long side of the rectangular slot is set along the long side of the rectangular waveguide, and the rectangular slot is located directly above the electric field energy focusing region.
9. The I-shaped slotted radiating antenna based on electromagnetic metamaterial design according to claim 1, characterized in that, The thickness of the electromagnetic metamaterial structure increases in a linear, periodic, exponential, logarithmic, or step gradient along the axial direction of the rectangular waveguide.