Light paper-based planar lens for electromagnetic wave beam modulation and planar antenna thereof

Abstract

The invention discloses a lightweight paper-based planar lens for electromagnetic wave beam modulation and a planar antenna thereof, and belongs to the technical field of antennas. The paper base main body is formed by forming a cavity structure which is surrounded by a sheet-shaped paper base and is periodically arranged at intervals, and the paper base main body is provided with an upper plane and a lower plane which are opposite to each other and are respectively an incident plane and an emergent plane of electromagnetic waves; thin-film-shaped symbol units made of metal materials are distributed and attached to the sheet-shaped paper base; according to the symbol units, the metal surface area of the symbol units in the unit volume in the paper-based main body is compared, and the metal surface area of the unit volume in the middle of the plane lens is larger than the periphery of the plane lens. The feed source is mounted close to the incident plane; the electromagnetic waves are propagated in the plane lens in a curve path and converge and are emitted out of the plane lens. When the feed source moves, wide-angle scanning of wave beams can be achieved, the gain reduction of the planar antenna is smaller than 2dB within the scanning range of + / -50 degrees, and meanwhile very high gain and aperture efficiency can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of antennas, and in particular relates to a lightweight paper-based planar lens and a planar antenna thereof for electromagnetic wave beam modulation. Background Art

[0002] With the rapid development of the new generation of mobile communication technology (B5G / 6G), there is an urgent need for antennas with large bandwidth, high gain, and wide angle scanning. As a form of high-gain antenna, the main advantages of large-aperture lens antennas are high gain, high efficiency, and no need for a feeding network. In recent years, they have attracted widespread attention from academia and industry. At present, there are two main forms of classic large-aperture lens antennas: spherical Luneburg lens antennas and transmission array antennas.

[0003] Among them, the working principle of the spherical Luneburg lens antenna is to refract electromagnetic waves multiple times through a spherical multi-faceted refractive lens, and finally form scattered light, thereby achieving the effect of amplifying light. For example, in the prior art, the Chinese patent with publication number CN105917525A discloses an antenna system and processing method, and the prior art mentions that the focusing device can use a Luneburg lens. However, the Luneburg lens antennas on the market are generally made of ceramics, but the dielectric constant of ceramics is high and the bandwidth is narrow, which makes it difficult to achieve multi-band. In addition, the hardness of ceramics is high, the weight is large and the cost is high, which is not conducive to transportation and is not suitable for industrialization. Some Luneburg lens antennas can also be made of dielectric materials such as polytetrafluoroethylene, but due to their complex structure and special material requirements, the difficulty and cost of their manufacturing and maintenance are increased, so that they also have certain disadvantages in terms of efficiency, structure and cost. Moreover, the feed source of the Luneburg lens can only be installed on a curved surface, and the installation of the curved surface is difficult.

[0004] The transmission array antenna realizes phase modulation of the electromagnetic waves reaching the surface through the resonant structure on the aperture surface. For example, in the prior art, the Chinese patent with publication number CN105071051A discloses an improved Fabry-Pérot resonant cavity antenna; it includes a feed source and a partial reflector, the feed source is a rectangular patch antenna, the partial reflector is placed parallel to the feed source, and the height of the resonant cavity formed between the feed source and the partial reflector is h; the partial reflector is a double-sided coating structure, the upper surface of which is a periodically arranged copper-clad array, and the lower surface is a periodically arranged hollow cross-shaped copper-clad square array; the partial reflector PRS structure makes its reflection coefficient modulus larger, which improves the feed antenna gain, and the reflection coefficient phase has a positive correlation with the frequency, so that the impedance bandwidth and gain bandwidth are improved. However, due to the use of a resonant structure, the working bandwidth of the transmission array antenna is narrower.

[0005] In addition, traditional antennas have only one central focus. In order to make the electromagnetic waves radiated by the antenna be emitted in parallel, the feed source must be placed at the central focus. Once the feed source deviates from the central focus, the gain of the antenna will drop sharply, and the antenna's beam scanning angle will become smaller.

[0006] Therefore, how to achieve high-gain, narrow-beam, multi-beam, low-power and lightweight lens antennas is a technical challenge that needs to be studied and overcome urgently in this field. Summary of the invention

[0007] In view of the problems in the related art, the present invention proposes a lightweight paper-based planar lens and a planar antenna for electromagnetic wave beam tuning to overcome the above-mentioned technical problems existing in the existing related art. The planar lens of the present invention comprises a paper-based main body, which is formed by a sheet-like paper base surrounding a periodically arranged hole structure; the sheet-like paper base is distributed with symbol units of a thin film of metal material; a feed source is installed close to the surface of the paper-based main body; in the present invention, the feed source can be placed at any position of the incident plane, and when the feed source moves, the present invention can also realize wide-angle scanning of the beam, and within the scanning range of ±50 degrees, the gain drop of the planar antenna is less than 2dB; at the same time, the present invention can also achieve the beneficial effects of high gain, narrow beam, multi-beam, low power consumption and lightweight.

[0008] The technical solution of the present invention is implemented as follows: a lightweight paper-based planar lens for electromagnetic wave beam modulation comprises a paper-based main body, wherein the paper-based main body is formed by a sheet-like paper base surrounding a periodically spaced cavity structure, and has two opposing upper and lower planes, which are respectively an incident plane and an exit plane of the electromagnetic wave;

[0009] The sheet-like paper base is distributed with symbol units made of thin-film metal material;

[0010] Furthermore, the attachment method of the symbol unit includes but is not limited to printing and pasting;

[0011] It should be noted that: the symbol unit is attached to the surface of the sheet-like paper base, or the symbol unit is arranged inside the sheet-like paper base, which also has the same technical effect;

[0012] For the symbol unit, when comparing the metal surface area of ​​the symbol unit per unit volume in the paper base body, the metal surface area per unit volume in the middle of the plane lens is greater than that in the periphery of the plane lens.

[0013] Furthermore, the incident plane and the exit plane are two opposite planes arranged in parallel;

[0014] The paper base body is cylindrical, polygonal or frustum-shaped;

[0015] The cavity structure is a circular or polygonal three-dimensional columnar cavity structure.

[0016] Furthermore, at the position where the metal surface area per unit volume is the largest, the metal surface area gradually decreases in the radial direction toward the circumferential side; or decreases in steps; or decreases periodically;

[0017] It should be noted that the step reduction means that the reduction of the metal surface area is not a continuous and smooth decline, but in the process of decline, some obvious turning points or plateaus may appear, so that the decline speed slows down or pauses near these points, thus forming a step-like shape;

[0018] The periodic reduction means that during the reduction of the metal surface area, its value shows a periodic downward trend. This periodic change usually means that within a fixed time interval, the value of the curve will experience a complete rise and fall process, and this process will be repeated to form periodic fluctuations.

[0019] Furthermore, the electromagnetic wave refractive index per unit volume position of the largest metal surface area is set as n0, the height between the upper and lower opposing surfaces of the paper base body is set as h, and the radial distance extending along the circumferential direction with n0 as the center is set as R, then the refractive index n(R) at the R position conforms to the following distribution rule:

[0020] Where e is a natural constant;

[0021] It should be noted that the larger the metal surface area, the larger the value of n0, and the larger the final refractive index n(R); however, in practical applications, the value range of n0 is generally between 1 and 3. A higher n0 can also be achieved, but the specific implementation will be relatively difficult.

[0022] Further, the focal plane of the plane lens is set at the incident plane;

[0023] It should be noted that: traditional antennas generally have only one central focus, and the feed source needs to be placed at the central focus, extending along the central focus position and perpendicular to the optical axis to form a plane. If the feed source is placed at a position on this plane that deviates from the central focus, the convergence effect of the electromagnetic waves emitted by the feed source will become worse; however, the entire incident plane of the plane lens described in the present invention is the focal plane, and the refraction effect of the electromagnetic waves emitted by the feed source at any position on the focal plane is basically the same. The present invention will not have the problem of a sharp drop in antenna gain and a decrease in the antenna beam scanning angle.

[0024] Further, the symbol unit is arranged on the side wall surrounding and facing the cavity structure, and the unit volume covers at least one cavity structure in the plane direction and contains at least one symbol unit in the vertical direction; in the present invention, it means that at least one cavity structure is included on the horizontal plane of the planar lens, and at least one symbol unit is included on the vertical plane perpendicular to the horizontal plane;

[0025] At least one of the arrangement density, size, and shape of the symbol units in part of the hole structure is different from that in another part of the hole structure; it should be noted that within the same paper base body, the symbol units with different hole structures are different; in the present invention, different equivalent dielectric constants can be obtained by adjusting the symbol units.

[0026] Furthermore, the shape of each of the symbol units includes an I-shape, and the size of the equivalent dielectric constant is changed by adjusting the length of each side of the I-shape; wherein the length of the side is positively correlated with the size of the equivalent dielectric constant, that is, the larger the length of the side, the higher the equivalent dielectric constant;

[0027] Furthermore, the value range of the equivalent dielectric constant is 1-2;

[0028] It should be noted that the shape of the symbol unit also includes a cross structure and a ring structure.

[0029] Furthermore, the symbol unit is made of a metal material with high conductivity.

[0030] Furthermore, the material of the paper base includes aramid paper;

[0031] In the present invention, the paper base includes but is not limited to being made of aramid paper, and the symbol unit is fixed on the aramid paper by printing or attaching;

[0032] Furthermore, the paper base can also be made of a flexible PCB board, and the symbol unit is fixed on the flexible PCB board by printing or attaching.

[0033] A planar antenna for wide-angle, high-gain beam scanning, comprising the planar lens described above; and

[0034] A mobile feed source moves back and forth along a straight line or a plane angle, is installed close to the incident plane, and the moving track extends along the incident plane; so that the reciprocating feed source can achieve a scanning technical effect;

[0035] Electromagnetic waves propagate in a curved path inside the plane lens and are collimated and emitted outside the plane lens.

[0036] A multi-beam planar antenna for large bandwidth and high gain, comprising the above-mentioned planar lens; and

[0037] A plurality of fixed feed sources are distributed along a straight line or a plane and installed close to the incident plane;

[0038] Furthermore, the output surfaces of the electromagnetic waves of the fixed feed sources are located at the same height;

[0039] Electromagnetic waves from different feed sources propagate in a curved path inside the plane lens and are collimated and emitted outside the plane lens at different angles;

[0040] Furthermore, the electromagnetic waves propagating in the plane lens are emitted to the outside of the plane lens in the form of plane waves;

[0041] The present invention realizes the multi-beam effect by simultaneously setting a plurality of fixed feed sources, wherein one fixed feed source corresponds to one beam; under the condition of multiple beams, a plurality of electromagnetic waves at different angles will be emitted in the form of plane waves in different directions after being emitted.

[0042] Furthermore, the focal plane of the plane lens is set to coincide with the incident plane, and the feed source is installed close to the surface of the paper-based body;

[0043] It should be noted that: in the prior art, the feed source of the Luneburg lens can only be installed on a curved surface, which is difficult to install on a curved surface, while the feed source of the plane lens of the present invention is directly installed along a plane, and plane installation is simpler and more convenient than curved surface installation. Therefore, compared with the existing Luneburg lens, the plane lens of the present invention is easier to install the feed source;

[0044] The gain roll-off of the electromagnetic wave emitted by a feed source located at any position on the focal plane after being radiated by the plane lens is less than 2 dB.

[0045] Furthermore, the antenna aperture plane refers to the cross section of the planar antenna.

[0046] Beneficial effects of the present invention:

[0047] The planar antenna of the present invention comprises a light paper-based planar lens and a feed source for electromagnetic wave beam adjustment, wherein the planar lens is formed by a sheet of paper surrounded by a periodically spaced cavity structure. Unlike a spherical Luneburg lens antenna, the cross-section of the planar antenna of the present invention is a planar structure, so multiple feed sources can be placed on the incident plane of the planar lens at the same time, making the installation of the feed source easier.

[0048] Secondly, traditional Luneburg lens antennas are usually made by manufacturing dielectric materials such as polytetrafluoroethylene into dielectric spheres, then punching holes in different sphere layers to obtain equivalent artificial material Luneburg lens antennas made of a mixture of dielectric and air. The refractive index of the planar lens of the present invention is controlled by a symbol unit attached to a sheet of paper base, which makes the operation easier.

[0049] In addition, the mobile feed of the present invention can be placed at any position of the incident plane, and the present invention can also set multiple fixed feeds to be placed at multiple different positions of the incident plane. Compared with the transmission array antenna, the biggest advantage of the present invention is that when the feed is moved or multiple fixed feeds are set, the present invention can achieve wide-angle scanning of the beam, and within the scanning range of ±50 degrees, the gain roll-off of the planar antenna is less than 2dB, and very high gain and aperture efficiency can be achieved; at the same time, the present invention can also achieve the effect of multiple beams. Moreover, the bandwidth of the wide-angle scanning achieved by the planar antenna of the present invention can reach 80%, which is much wider than the bandwidth of the traditional planar transmission antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a schematic structural diagram of the basic structure of the plane lens of the present invention;

[0051] Figure 2 It is a schematic diagram of the radial decrease of the refractive index on the aperture surface of the antenna of the present invention;

[0052] Figure 3 It is a schematic diagram of the refractive index distribution on the aperture surface of the antenna of the present invention;

[0053] Figure 4 It is a schematic diagram of the radiation trajectory of the electromagnetic wave in the plane lens of the present invention;

[0054] Figure 5 It is a structural schematic diagram of a symbol unit sprayed on aramid paper of the present invention;

[0055] Figure 6 is a top view of the planar antenna of the present invention;

[0056] Figure 7 is a side view of the planar antenna of the present invention;

[0057] Figure 8 It is a schematic diagram of the positions of multiple fixed feed sources on the incident plane of the present invention;

[0058] Fig. 9 It is a curve diagram showing the change of the gain of the planar antenna with the beam scanning angle when excited by different feed sources of the present invention;

[0059] Fig.10 It is a schematic diagram of a curve showing how the gain at different beam scanning angles varies with frequency according to the present invention. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0062] Example 1

[0063] like Figure 1 As shown, this embodiment provides a lightweight paper-based planar lens for electromagnetic wave beam modulation, comprising a paper-based main body, wherein the paper-based main body is formed by a sheet-like paper base surrounding a periodically spaced cavity structure, and has two upper and lower opposing planes, which are respectively an incident plane and an exit plane of the electromagnetic wave;

[0064] like Figure 5-7 As shown, the sheet-like paper base is distributed with thin-film-like metal material symbol units;

[0065] Specifically, the attachment method of the symbol unit includes but is not limited to printing and pasting;

[0066] It should be noted that: the symbol unit is attached to the surface of the sheet-like paper base, or the symbol unit is arranged inside the sheet-like paper base, which also has the same technical effect;

[0067] The symbol unit, comparing the metal surface area of ​​the symbol unit per unit volume in the paper base body, the metal surface area per unit volume in the middle of the plane lens is greater than the periphery of the plane lens; so that the refractive index in the middle of the plane lens is greater than the refractive index at the periphery, such as Figure 3 As shown, the refractive index of the plane lens decreases from the middle position to two sides.

[0068] Specifically, the incident plane and the exit plane are two opposite planes arranged in parallel;

[0069] The paper base body is cylindrical, polygonal or frustum-shaped;

[0070] It should be noted that this embodiment does not limit the shape of the paper-based body. In addition to the cylindrical shape, it can also be any other three-dimensional structure. In this embodiment, the cylindrical shape is preferred. The advantage of using a cylindrical shape is that the power of the electromagnetic waves radiated from the plane lens can be symmetrical in all directions.

[0071] Specifically, at the position where the metal surface area per unit volume is the largest, the metal surface area gradually decreases in the radial direction toward the circumferential side; or decreases in steps; or decreases periodically;

[0072] It should be noted that the step reduction means that the reduction of the metal surface area is not a continuous and smooth decline, but in the process of decline, some obvious turning points or plateaus may appear, so that the decline speed slows down or pauses near these points, thus forming a step-like shape;

[0073] The periodic decrease means that during the reduction of the metal surface area, its value presents a periodic downward trend. This periodic change usually means that within a fixed time interval, the value of the curve will experience a complete rise and fall process, and this process will be repeated, forming a periodic fluctuation.

[0074] Specifically, the antenna aperture plane refers to the cross section of the planar antenna; in order to achieve a large beam scanning angle when the subsequent feed source moves on the incident plane, while ensuring that the gain does not drop significantly, a gradient refractive index is constructed on the antenna aperture plane, such as Figure 2-3 As shown;

[0075] More specifically, the electromagnetic wave refractive index at the unit volume position where the metal surface area is the largest is set to n0, the height between the upper and lower opposing surfaces of the paper base body is set to h, and the radial distance extending circumferentially with n0 as the center is set to R, then the refractive index n(R) at the R position conforms to the following distribution rule:

[0076] Where e is a natural constant;

[0077] It should be noted that if Figure 2 As shown, the larger the metal surface area, the larger the value of n0, and the larger the final refractive index n(R); but in practical applications, the value range of n0 is generally between 1 and 3, and a higher n0 can also be achieved, but the specific implementation will be relatively difficult.

[0078] According to the above formula, the refractive index corresponding to each point on the antenna aperture surface can be obtained by calculation. The refractive index distribution on the antenna aperture surface is as follows: Figure 3As shown, the refractive index at the center of the antenna aperture surface is the highest, and the refractive index gradually decreases from the center along the surrounding edges.

[0079] Specifically, the focal plane of the plane lens is set at the incident plane;

[0080] It should be noted that: traditional antennas generally have only one central focus, and the feed source needs to be placed at the central focus, extending along the central focus position and perpendicular to the optical axis to form a plane. If the feed source is placed at a position on this plane that deviates from the central focus, the convergence effect of the electromagnetic waves emitted by the feed source will become worse; however, the entire incident plane of the plane lens described in this embodiment is the focal plane, and the refraction effect of the electromagnetic waves emitted by the feed source at any position on the focal plane is basically the same. In this embodiment, the problem of a sharp drop in antenna gain and a decrease in the antenna beam scanning angle will not occur.

[0081] Specifically, the symbol unit is arranged on the side wall surrounding and facing the cavity structure, and the unit volume covers at least one cavity structure in the plane direction and contains at least one symbol unit in the vertical direction; in this embodiment, it means that at least one cavity structure is included on the horizontal plane of the planar lens, and at least one symbol unit is included on the vertical plane perpendicular to the horizontal plane;

[0082] At least one of the arrangement density, size, and shape of the symbol units in part of the hole structure is different from that in another part of the hole structure; it should be noted that within the same paper base body, the symbol units with different hole structures are different; in this embodiment, different equivalent dielectric constants are obtained by adjusting the symbol units.

[0083] Specifically, the symbol unit is made of a metal material with high conductivity, which may be silver paste, copper, etc. In this embodiment, silver paste is preferably used.

[0084] Specifically, the material of the paper base includes aramid paper.

[0085] In this embodiment, the paper base includes but is not limited to being made of aramid paper, and the symbol unit is fixed on the aramid paper by printing or attaching;

[0086] It should be noted that: in a plane lens, the paper-based body mainly plays a supporting role, and the paper-based body made of aramid paper used in this embodiment has a more unique spatial structure and mechanical properties; moreover, aramid paper has excellent chemical inertness and can immediately self-extinguish when away from the fire source, and has good heat insulation, temperature resistance, electrical insulation and electromagnetic wave transmission properties;

[0087] The cavity structure is a circular or polygonal three-dimensional columnar cavity structure;

[0088] In this embodiment, the cavity structure can be specifically a hexagonal three-dimensional columnar void structure; the hexagonal three-dimensional columnar void structure makes the paper base body have better axial compression and impact resistance, and has excellent sound insulation and fatigue resistance, and also makes the plane lens have a lower density, so the overall mass is lighter than other materials; moreover, the cavity structure is arranged in a hexagonal shape, so that subsequent electromagnetic waves can be radiated in the form of plane waves, which can not only achieve large-angle radiation, but also ensure that the gain will not decrease significantly;

[0089] In this embodiment, in order to achieve an equivalent gradient refractive index, a symbol unit is firstly arranged on a sheet-like paper base, and then the size of the symbol unit is adjusted to achieve different equivalent refractive indices;

[0090] It should be noted that the medium in the cavity structure is air, and the dielectric constant of air is 1.0, while the dielectric constant of the paper base body is different from the dielectric constant of air. When the equivalent dielectric constant of the plane lens is to be increased, the size of the final equivalent dielectric constant can be changed by adjusting the length of each side of the symbol unit.

[0091] Specifically, the shape of each symbol unit includes an I-shape, and the size of the equivalent dielectric constant is changed by adjusting the length of each side of the I-shape; wherein the length of the side is positively correlated with the size of the equivalent dielectric constant, that is, the larger the length of the side, the higher the equivalent dielectric constant;

[0092] More specifically, the value range of the equivalent dielectric constant is 1-2;

[0093] like Figure 5 As shown, in this embodiment, the equivalent dielectric constant is changed by printing an "I"-shaped structure on aramid paper, wherein the change of the equivalent dielectric constant is mainly achieved by adjusting the length of each side of the "I"-shaped structure;

[0094] Specifically, the shape of the symbol unit described in this embodiment includes but is not limited to an “I” shape, and the shape of the symbol unit also includes a cross structure and a ring structure;

[0095] It should be noted that: this embodiment is simulated by electromagnetic simulation software; according to the theory and simulation results, when the area ratio of the symbol unit and the single side wall of the hole structure is the same, no matter how the shape, density, etc. of the symbol unit changes, the equivalent dielectric constant finally achieved is similar.

[0096] More specifically, the paper base can also be made of a flexible PCB board, and the symbol unit is fixed on the flexible PCB board by printing or attaching.

[0097] Example 2

[0098] This embodiment further provides a light paper-based flat lens for electromagnetic wave beam modulation. The features not explained in this embodiment can be explained in Example 1, and will not be described in detail here. The difference between this embodiment and Example 1 is that:

[0099] The paper base is replaced by a plastic material.

[0100] Example 3

[0101] This embodiment provides a planar antenna for wide-angle, high-gain beam scanning. The features not explained in this embodiment can be explained in Example 1, and will not be described in detail here. The difference between this embodiment and Example 1 is:

[0102] comprising the above-mentioned plane lens; and,

[0103] A mobile feed source moves back and forth along a straight line or a plane angle, is installed close to the incident plane, and the moving track extends along the incident plane; so that the reciprocating feed source can achieve a scanning technical effect;

[0104] The electromagnetic wave propagates in a curved path inside the plane lens and is collimated to exit the plane lens;

[0105] like Figure 7 As shown, the focal plane of the plane lens is set to coincide with the incident plane, and the feed source is installed close to the surface of the paper-based body to ensure that the planar antenna can achieve large-angle radiation of electromagnetic waves and high gain of the antenna;

[0106] like Figure 8-9 As shown, no matter where the mobile feed source is installed on the incident plane, the beam scanning angle of the planar antenna changes, and the gain also changes accordingly; Fig. 9 Taking the feed source 3 in the figure as an example, as the beam scanning angle of the plane lens changes from 0 degree to ±50 degrees, the gain also decreases periodically from 20 dBi;

[0107] More specifically, the electromagnetic wave emitted by the feed source at any position on the focal plane has a gain roll-off of less than 2 dB after being radiated by the plane lens; wherein the gain roll-off refers to the gain of different beams compared to the maximum gain of all beams;

[0108] like Fig.10 As shown in Figure 1, the gain of different beam scanning angles varies with the frequency, but in the wide frequency range of 1.8 GHz to 3.8 GHz, the gain drop of different beam scanning angles is within 2 dB. Fig.10 Taking the beam scanning angle of 0 degrees as an example, when the frequency changes from 2.0GHz to 2.1GHz, the gain drop is significantly less than 2dB. Figure 4 As shown, this embodiment shows the propagation path of electromagnetic waves inside the plane lens. Due to the existence of the symbol unit, after the feed source emits electromagnetic waves from different positions, they are all transmitted to the exit plane in the form of a curve inside the plane lens, and are propagated to the outside of the plane lens in the form of a plane wave after being refracted by the exit plane. Therefore, in this embodiment, a mobile feed source can be placed at any position on the incident plane, and the electromagnetic waves can eventually be radiated out in the form of a plane wave, thereby achieving large-angle radiation while ensuring that the gain does not decrease significantly.

[0109] The formula in Example 1 can be used to calculate the required refractive index on the antenna aperture plane, and then the symbol unit of the corresponding refractive index is set at the corresponding position to obtain the planar antenna described in this embodiment.

[0110] In addition, in this embodiment, whether aramid paper or flexible PCB board is used, under the condition of the same volume, the weight of both is much lighter than the weight of ceramics, which is beneficial to reducing the transportation cost of the planar antenna; moreover, for manufacturers, the larger the volume of the antenna, the higher the processing cost of ceramics, but the processing cost of aramid paper is lower than that of ceramics. Therefore, the planar antenna described in this embodiment is also conducive to large-scale production.

[0111] Example 4

[0112] This embodiment also provides a multi-beam planar antenna for large bandwidth and high gain. The features not explained in this embodiment can be explained in Example 1, and will not be repeated here. The difference between this embodiment and Examples 1 and 3 is:

[0113] comprising the above-mentioned plane lens; and,

[0114] A plurality of fixed feed sources are distributed along a straight line or a plane and installed close to the incident plane;

[0115] Electromagnetic waves from different feed sources propagate in a curved path inside the plane lens and are collimated and emitted outside the plane lens at different angles;

[0116] Specifically, electromagnetic waves propagating in the plane lens are emitted to the outside of the plane lens in the form of plane waves;

[0117] This embodiment achieves a multi-beam effect by setting up multiple fixed feed sources at the same time, where one fixed feed source corresponds to one beam; under the condition of multiple beams, multiple electromagnetic waves at different angles will be emitted in the form of plane waves in different directions.

[0118] Specifically, the focal plane of the planar lens is set to coincide with the incident plane, and the feed source is installed close to the surface of the paper-based body to ensure that the multi-beam planar antenna can achieve large-angle radiation of electromagnetic waves and high gain of the antenna;

[0119] It should be noted that: in the prior art, the feed source of the Luneburg lens can only be installed on a curved surface, which makes curved surface installation difficult, while the feed source of the plane lens described in this embodiment is directly installed along a plane, which is simpler and more convenient than curved surface installation. Therefore, compared with the existing Luneburg lens, the plane lens of this embodiment is easier to install the feed source.

[0120] like Figure 8-9 As shown, a plurality of the fixed feed sources are installed at any position on the incident plane, and when the beam scanning angle of the planar antenna changes, the gain will also change accordingly; Fig. 9 Taking feed 3 in the figure as an example, as the beam scanning angle changes from 0 degrees to ±50 degrees, the gain also decreases periodically from 20dBi;

[0121] More specifically, the gain roll-off of the electromagnetic wave emitted by the feed source at any position on the focal plane after being radiated by the plane lens is less than 2 dB;

[0122] like Fig.10 As shown in Figure 1, the gain of different beam scanning angles varies with the frequency, but in the wide frequency range of 1.8 GHz to 3.8 GHz, the gain drop of different beam scanning angles is within 2 dB. Fig.10 Taking the beam scanning angle of 0 degree in as an example, when the frequency changes from 2.0GHz to 2.1GHz, the gain decrease is significantly less than 2dB.

[0123] The multi-beam planar antenna in this embodiment includes a lightweight paper-based planar lens and multiple fixed feeds for electromagnetic wave beam adjustment. The multiple fixed feeds in this embodiment can be arbitrarily placed at different positions on the incident plane. Compared with the transmission array antenna, the biggest advantage of this embodiment is that when multiple fixed feeds are set, the multi-beam planar antenna in this embodiment can achieve wide-angle scanning of multiple beams, and within the scanning range of ±50 degrees, the gain roll-off of the multi-beam planar antenna is less than 2dB, and at the same time, very high gain and aperture efficiency can be achieved. The bandwidth of the wide-angle scanning achieved by the multi-beam planar antenna in this embodiment can reach 80%, which is much wider than the bandwidth of the traditional planar transmission antenna.

[0124] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A lightweight paper-based planar lens for electromagnetic wave beam modulation, comprising a paper-based main body, characterized in that: The paper base body is formed by a sheet-like paper base surrounding a periodically spaced hole structure, and has two opposing planes, an upper plane and a lower plane, which are respectively an incident plane and an exit plane of electromagnetic waves; The sheet-like paper base is distributed with symbol units made of thin-film metal material; For the symbol unit, when comparing the metal surface area of ​​the symbol unit per unit volume in the paper base body, the metal surface area per unit volume in the middle of the plane lens is greater than that in the periphery of the plane lens.

2. The lightweight paper-based flat lens for electromagnetic wave beam modulation according to claim 1, characterized in that: The incident plane and the exit plane are two opposite planes arranged in parallel; The paper base body is cylindrical, polygonal or frustum-shaped; The cavity structure is a circular or polygonal three-dimensional columnar cavity structure.

3. The lightweight paper-based flat lens for electromagnetic wave beam modulation according to claim 1, characterized in that: At the position where the metal surface area per unit volume is the largest, the metal surface area gradually decreases along the radial direction toward the circumferential side; or decreases in steps; or decreases periodically.

4. The lightweight paper-based flat lens for electromagnetic wave beam modulation according to claim 1 or 3, characterized in that: The electromagnetic wave refractive index per unit volume position of the largest metal surface area is set as n0, the height between the upper and lower opposing surfaces of the paper base body is set as h, and the radial distance extending circumferentially with n0 as the center is set as R, then the refractive index n(R) at the R position conforms to the following distribution rule: Where e is a natural constant.

5. The lightweight paper-based flat lens for electromagnetic wave beam modulation according to claim 1, characterized in that: The focal plane of the plane lens is arranged on the incident plane.

6. The lightweight paper-based flat lens for electromagnetic wave beam modulation according to claim 1 or 2, characterized in that: The symbol unit is arranged on a side wall surrounding and facing the cavity structure, the unit volume covers at least one cavity structure in the planar direction and contains at least one symbol unit in the vertical direction; At least one of the arrangement density, size, and shape of the symbol units in a portion of the hole structures is different from that in another portion of the hole structures.

7. The lightweight paper-based flat lens for electromagnetic wave beam modulation according to claim 1, characterized in that: The material of the paper base includes aramid paper.

8. A planar antenna for wide-angle, high-gain beam scanning, characterized in that: comprising the plane lens as claimed in any one of claims 1 to 7; and A mobile feed source reciprocates along a straight line or a plane angle and is installed close to the incident plane, with a moving trajectory extending along the incident plane; Electromagnetic waves propagate in a curved path inside the plane lens and are collimated and emitted outside the plane lens.

9. A multi-beam planar antenna for large bandwidth and high gain, characterized in that: comprising the plane lens as claimed in any one of claims 1 to 7; and A plurality of fixed feed sources are distributed along a straight line or a plane and installed close to the incident plane; Electromagnetic waves from different feed sources propagate in a curved path inside the plane lens and are collimated and emitted outside the plane lens at different angles.

10. The planar antenna according to claim 8 or 9, characterized in that: The focal plane of the plane lens is set to coincide with the incident plane, and the feed source is installed close to the surface of the paper-based body; The gain roll-off of the electromagnetic wave emitted by a feed source located at any position on the focal plane after being radiated by the plane lens is less than 2 dB.

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