CN113922098A - Wide beam plane lens antenna with variable beam width - Google Patents
Wide beam plane lens antenna with variable beam width Download PDFInfo
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- CN113922098A CN113922098A CN202111269539.3A CN202111269539A CN113922098A CN 113922098 A CN113922098 A CN 113922098A CN 202111269539 A CN202111269539 A CN 202111269539A CN 113922098 A CN113922098 A CN 113922098A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
- H01Q15/02—Refracting or diffracting devices, e.g. lens, prism
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/002—Protection against seismic waves, thermal radiation or other disturbances, e.g. nuclear explosion; Arrangements for improving the power handling capability of an antenna
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
- H01Q13/02—Waveguide horns
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
- H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
- H01Q15/0086—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
- H01Q19/06—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using refracting or diffracting devices, e.g. lens
- H01Q19/08—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using refracting or diffracting devices, e.g. lens for modifying the radiation pattern of a radiating horn in which it is located
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
- H01Q3/30—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the relative phase between the radiating elements of an array
- H01Q3/34—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the relative phase between the radiating elements of an array by electrical means
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- Aerials With Secondary Devices (AREA)
Abstract
The invention discloses a variable beam width wide beam planar lens antenna, which comprises a horn feed source antenna and a planar lens, wherein the planar lens realizes the refraction of electromagnetic waves by setting a gradient phase, and an additional gradient phase delta is added on the H surface of the antenna on the basis of compensating the spatial phase caused by the optical path differencenThe planar lens is composed of 51 multiplied by 51 phase shift units, the phase shift units adopt two layers of media and a copper-clad structure on the upper, middle and lower three layers, and the thickness is very thin. To is coming toThe design is simplified, the processing cost is reduced, and 8 phase shift units are selected to cover the phase shift range of 0-360 degrees. The focusing performance of the lens on two main planes is different by introducing a beam widening phase to control the beam width, the phase shift required by each position is obtained according to a calculation formula of each point of the planar lens, and the phase shift units are arranged according to a specified phase distribution diagram to obtain the planar lens antenna with the specified beam width.
Description
Technical Field
The invention relates to the technical field of antennas in passive devices, in particular to a wide-beam planar lens antenna with variable beam width.
Background
In recent years, intelligent driving modes such as auxiliary driving and automatic driving bring vigorous development opportunities for millimeter wave automobile radars. Compared with the traditional sensor, the ultrasonic radar and the infrared sensor, the 77Ghz millimeter wave automobile radar system has good performance under the complex weather conditions of night, rainstorm, heavy fog and the like. In consideration of the space limitation of the vehicle, the automotive radar antenna is required to be light in weight, low in profile and low in cost. Millimeter-wave radars, however, suffer from the problems of being bulky, small, and having poor performance.A planar lens array consisting of a periodic series of sub-wavelength elements has received much attention from researchers due to its high flexibility in beamforming and low cost. Compared with the traditional phased array and dielectric lens, the planar lens antenna has the advantages of low appearance, low cost, light weight, simple manufacturing process and the like, and is widely applied to the fields of automobile radars, 5G communication and the like.
Planar lens cells are typically constructed by etching a metal conductor over a multilayer dielectric. In order to realize a larger phase shift range, the number of dielectric layers is usually relatively large and the thickness is thicker, but compared with a cylindrical or spherical dielectric lens, the planar structure of the dielectric lens is small and light. Compared with a phased array antenna, the lens antenna avoids the design of a complex feed network, is easier to process, and is lower in cost. The planar lens antenna is flexible in design and strong in expansibility, the design is mainly focused on designing a phase shift unit with high transmission performance and an efficient phase distribution mode, a series of high-performance units are arranged according to the given phase distribution mode, different beam shapes can be obtained, and given design indexes are achieved.
At present, the design of the variable-width wide-beam antenna mainly has the following difficulties: if the phased array mode is adopted for realization, a complex feed network is inevitably designed, the size of the 77GHz antenna is often very small, the feed network is particularly difficult to design and process, and the cost is very high; if the dielectric lens is adopted, the dielectric lens is generally in a three-dimensional structure, occupies a large space and is difficult to integrate. The planar lens antenna can solve the above problems well, the phase shift range of the phase shift unit based on the metamaterial is usually narrow, and the profile height of the phase shift unit is usually required to be increased in order to increase the phase shift range, which causes the lens to be heavy. Therefore, how to design a set of low-profile, small-sized, high-performance phase shift units to cover a phase shift range of 360 °, and design an antenna with high gain and wide beam characteristics in a set of unit arrangement mode becomes a technical problem to be solved by those skilled in the art.
Disclosure of Invention
In order to solve the above problems, the present invention provides a planar lens antenna with simple structure, controllable beam width, high antenna gain, and small array plane size.
In order to achieve the purpose, the invention is realized by the following technical scheme:
the invention relates to a variable beam width wide beam planar lens antenna, which comprises a horn feed source antenna and a planar lens consisting of a plurality of phase shift units, wherein the planar lens realizes the refraction of electromagnetic waves by setting a gradient phase, and an additional gradient phase delta is added on the H surface of the antenna on the basis of compensating the spatial phase caused by the optical path differencenGradient phase deltanAs follows:
wherein: n is the number of the current unit from left to right in the H plane, N is the total number of the units in the direction, alpha is a gradient coefficient, the beam width is controlled by changing the gradient coefficient alpha, the beam width is widened when alpha is increased,
and the gain will decrease.
The invention is further improved in that: the phase shift unit is composed of a three-layer metal resonance structure with double resonance characteristics and a double-layer medium, and the three-layer metal resonance structure is etched on the surface of the double-layer medium at intervals.
The invention is further improved in that: the dual-layer medium includes an upper medium and a lower medium made of a metamaterial.
The invention is further improved in that: the three-layer metal resonance structure is an upper-layer patch arranged on the outer surface of the upper-layer medium, a middle-layer patch arranged between the upper-layer medium and the lower-layer medium, and a lower-layer patch arranged on the outer surface of the lower-layer medium.
The invention is further improved in that: the upper layer patch, the middle layer patch and the lower layer patch are all made of copper, the upper layer patch and the lower layer patch are in a cross shape with the same size, and the middle layer patch is in a circular ring nested circular structure.
The invention is further improved in that: the sizes of the upper layer patch, the middle layer patch and the lower layer patch of the phase shift unit are adjusted to obtain 0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees and 315 degrees of phase shift units.
The invention is further improved in that: the total number of phase shift units of the whole wavefront of the planar lens is 51 × 51, the thickness is 0.5mm, and the length and the width of each phase shift unit are 2 mm.
The invention has the beneficial effects that: compared with the prior art, the invention has the following obvious characteristics and advantages:
1. the antenna has a simple structure. Compared with other wide-beam antennas, the planar lens antenna is simple in manufacturing process, does not need a feed network, and adopts a horn antenna feed source to perform aerial feed on an array surface. Only 8 phase shift units are adopted to cover a 360-degree phase shift range, and the array surface is light and thin and easy to integrate and manufacture.
2. The beam width is controllable. By changing the value of α in the beam broadening phase, the control of the beam width can be realized in the H plane, while the beam width of the E plane remains substantially unchanged, thereby realizing a wide beam effect.
3. The antenna gain is higher. The maximum gain of the planar lens antenna can reach 30.5dB, and compared with a feed source antenna, the gain is improved by 15 dB. Although the gain decreases with the broadening of the beam width, there is still a significant gain increase for the feed antenna.
4. The array surface is small in size and light and thin in thickness. The overall frontal dimensions are 102 × 102 × 0.5 mm.
Drawings
FIG. 1 is a schematic view of a planar lens antenna according to the present invention.
Fig. 2 is a view showing a distribution structure of the planar lens unit.
FIG. 3 is a schematic diagram of a planar lens phase shift unit.
Fig. 4 is a front view of a planar lens phase shift unit.
FIG. 5 is a side view of a planar lens phase shift unit.
FIG. 6 is a graph of transmission coefficient versus phase shifting power for 8 different planar lens phase shifting units.
Fig. 7 is a return loss result graph before and after loading the lens on the feed horn antenna.
Fig. 8 is the E-plane and H-plane patterns before the feed horn antenna is loaded with lenses.
Fig. 9 is the radiation patterns of the E-plane and the H-plane of the feed horn antenna after loading the lens.
Fig. 10 is a directional diagram of the antenna in the E plane when α is different.
The feed source.
Detailed Description
The following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings, will make the advantages and features of the invention easier to understand by those skilled in the art, and will thus define the scope of the invention more clearly and clearly. These examples are illustrative only and are not to be construed as limiting the invention since they are intended to be specifically described herein.
As shown in fig. 1 to 10, the variable beam width wide beam planar lens antenna of the present invention is a planar lens antenna based on a metamaterial, and has the characteristics of small volume, light weight, easy integration, and simple manufacture. The planar lens realizes the refraction of electromagnetic waves by setting gradient phases, thereby realizing the change of beam width and peak gain.
The metamaterial is an artificial synthetic material with abnormal electromagnetic characteristics which are not possessed by natural materials, and the planar lens unit manufactured by the metamaterial can change the phase of electromagnetic waves so as to change the shape of beams. The metamaterial is manufactured by etching a metal structure on the surface of a medium, and the capacity of changing the phase can be changed by changing the parameters such as the shape and the size of a metal conductor. To reduce the manufacturing difficulty, the 360 ° phase shift range is often quantified to different degrees and still maintain the good radiation performance of the planar lens. The metamaterial can be Rogers RT6002, namely, Rogers RT6002 media is adopted by the upper medium and the lower medium.
The feed source adopts a common horn antenna form, and the peak gain of the feed source is 15.5dB, the H-plane beam width is 34.4 degrees, and the E-plane beam width is 29.3 degrees through simulation. The planar lens phase shift unit adopts a form that the surface of a double-layer Rogers RT6002 medium is coated with copper, the structure of the planar lens phase shift unit is shown in FIG. 3, the dielectric materials and the dimensions of the planar lens phase shift unit are completely the same, the length and the width of the planar lens phase shift unit are both w equal to 2mm, and the thickness of the planar lens phase shift unit is 0.254 mm. The double-layer Rogers RT6002 medium is an upper-layer medium and a lower-layer medium respectively, the three-layer metal resonance structure is etched on the surfaces of the upper-layer medium and the lower-layer medium at intervals, namely, an upper-layer patch is etched on the outer surface of the upper-layer medium, a middle-layer patch is etched between the upper-layer medium and the lower-layer medium, and a lower-layer patch is etched on the outer surface of the lower-layer medium. The structure makes up the problem of insufficient phase shift range caused by small medium thickness, and finally realizes 360-degree large-range phase shift. The upper-layer patch, the middle-layer patch and the lower-layer patch are all copper conductors, the upper-layer patch and the lower-layer patch are the same in size and shape and are cross-shaped, and the middle-layer patch is of a circular ring nested circular structure. The phase shift unit S11 (reflection coefficient) is small and S21 (transmission coefficient) is large as demonstrated by simulations in CST microwave studio. The results show that the electromagnetic wave radiated from the feedhorn antenna can mostly pass through the phase shift unit, which is a prerequisite for designing a high performance transmission unit. By changing the size of the three layers of copper conductors, the phase shift structure which covers a phase range of 360 degrees and has good transmission performance is realized. The specific parameters of each phase shifting unit in this example are given below:
1.0 ° phase shift unit: w 1-0.6 mm, l 1-1.05 mm, r-1.1 mm, r 1-1.2 mm, r 2-1.3;
2. 45 ° phase shift unit: w 1-0.5 mm, l 1-1 mm, r 1-1.1 mm, r 2-1.2;
3. 90 ° phase shift unit: w 1-0.2 mm, l 1-0.95 mm, r-0.6 mm, r 1-0.7 mm, r 2-1;
4. 135 ° phase shift unit: w 1-0.1 mm, l 1-0.1 mm, r-0.4 mm, r 1-1.1 mm, r 2-1.36;
5. 180 ° phase shift unit: w 1-0.1 mm, l 1-0.48 mm, r-0.06 mm, r 1-0.16 mm, r 2-0.22;
6. 225 ° phase shift unit: w 1-1.09 mm, l 1-0.9 mm, r-1.16 mm, r 1-1.86 mm, r 2-1.96;
7. 270 ° phase shift unit: w 1-1 mm, l 1-1 mm, r-1.22 mm, r 1-1.72 mm, r 2-1.92;
8. 315 ° phase shift unit: w 1-0.86 mm, l 1-1 mm, r-1.14 mm, r 1-1.24 mm, r 2-1.34;
compared with a high-gain planar lens antenna, the wide-beam planar lens has the greatest difference in the distribution mode of the lens array surface phases. For a high-gain planar lens antenna, because the feed source is far away from the array surface, and the focal length is far larger than the size of the antenna, the feed source antenna is generally abstracted to be a point source, spherical waves are radiated by the feed source, and the spherical waves need to be converted into planar waves by the high-gain planar lens in order to realize the high-gain characteristic. This transformation is achieved by a specific phase gradient propagation from the center of the lens to the periphery. Through the analysis of the geometrical optics principle, the electromagnetic wave has an optical path difference between the central position of the lens and the edge position of the lens, so the phase difference of the phase shift units at the two points is as follows:
where m and n represent the number of phase shift elements on the H-plane and E-plane from the center of the lens, respectively, and p is the length and width of the element, i.e., 2mm, then m × p and n × p can represent the distance from any element of the wavefront to the center of the lens, and since the phase has a periodicity of 2 pi as a period, K is an arbitrary integer greater than or equal to 0.
In order to realize wide beam characteristics, the invention is arranged on a high gain planeThe phase profile of the lens antenna adds an extra beam broadening phase. By adding an extra gradient phase delta in the antenna H planenSo that the width of the H-plane beam is obviously widened and the width of the E-plane beam is basically kept unchanged. The additional phase gradient obeys the following equation:
in formula (2), N is the number of the current cell in the H plane from left to right, and N is the total number of cells in the direction. The beam width can be controlled by varying the gradient coefficient α, with the beam width widening as α increases and the gain decreasing. Therefore, the design method can be suitable for various different types of application scenes.
According to the formula (1), different alpha values are selected, the focal length F is 60mm, the phase shift required by each position is calculated, the designed phase shift units are sequentially arranged to form a 51 × 51 array, the total size is 102mm × 102mm, and the performance of the lens antenna is simulated by aligning the phase center of the feed antenna to the focal point of the planar lens.
When alpha is 0, the overall gain of the lens antenna is 30.5dB, the beam width of an H plane is 3.6 degrees, and the beam width of an E plane is 3 degrees;
when alpha is 0.5, the overall gain of the lens antenna is 28.6dB, the beam width of an H plane is 6.1 degrees, and the beam width of an E plane is 3 degrees;
when alpha is 1, the overall gain of the lens antenna is 26.4dB, the beam width of an H plane is 10.3 degrees, and the beam width of an E plane is 3 degrees;
when α is 2, the overall gain of the lens antenna is 23.5dB, the H-plane beam width is 14.8 °, and the E-plane beam width is 3 °.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (7)
1. AThe utility model provides a wide beam plane lens antenna of variable beam width, includes loudspeaker feed antenna and the plane lens of constituteing by several phase shift unit, its characterized in that: the planar lens realizes the refraction of electromagnetic waves by setting a gradient phase, wherein, on the basis of compensating the space phase caused by the optical path difference, an additional gradient phase delta is added on the H surface of the antennanGradient phase deltanAs follows:
wherein: n is the number of the current unit from left to right in the H plane, N is the total number of the units in the direction, alpha is a gradient coefficient, the beam width is controlled by changing the gradient coefficient alpha, the beam width is widened when alpha is increased, and the gain is reduced.
2. The variable beamwidth wide beamplane lens antenna of claim 1, wherein: the phase shift unit is composed of a three-layer metal resonance structure with double resonance characteristics and a double-layer medium, and the three-layer metal resonance structure is etched on the surface of the double-layer medium at intervals.
3. The variable beamwidth wide beamplane lens antenna of claim 2, wherein: the dual-layer medium includes an upper medium and a lower medium made of a metamaterial.
4. The variable beamwidth wide beamplane lens antenna of claim 3, wherein: the three-layer metal resonance structure is an upper-layer patch arranged on the outer surface of the upper-layer medium, a middle-layer patch arranged between the upper-layer medium and the lower-layer medium, and a lower-layer patch arranged on the outer surface of the lower-layer medium.
5. The variable beamwidth wide beamplane lens antenna of claim 4, wherein: the upper layer patch, the middle layer patch and the lower layer patch are all made of copper, the upper layer patch and the lower layer patch are in a cross shape with the same size, and the middle layer patch is in a ring nested circular structure.
6. The variable beamwidth wide beamplane lens antenna of claim 5, wherein: and adjusting the sizes of the upper layer patch, the middle layer patch and the lower layer patch of the phase shift unit to obtain 0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees and 315 degrees of phase shift units.
7. The variable beamwidth wide beamplane lens antenna of claim 1, wherein: the phase shift units of the whole wavefront of the planar lens are 51 × 51, the thickness is 0.5mm, and the length and the width of each phase shift unit are 2 mm.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114498040A (en) * | 2022-01-19 | 2022-05-13 | 西安电子科技大学 | Wave beam reconfigurable H-plane horn antenna based on double-ridge gap waveguide |
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2021
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114498040A (en) * | 2022-01-19 | 2022-05-13 | 西安电子科技大学 | Wave beam reconfigurable H-plane horn antenna based on double-ridge gap waveguide |
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