Integrated antenna

Abstract

The invention provides an integrated antenna, and belongs to the technical field of antennas. The integrated antenna is composed of a plastic shell and a conformal antenna, wherein the plastic shell is composed of a parabola-shaped head and a platform-shaped bottom, and the conformal antenna is attached to the plastic shell. The integrated antenna can maintain high-gain directional radiation of the antenna on a curved surface with a sharp angle.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and more particularly to an integrated antenna. Background Technology

[0002] Integrated antennas (such as spiral antennas, arched antennas, etc.) refer to antennas that are designed and manufactured as an integral part of the equipment structure.

[0003] Although integrated antennas have advantages such as being thinner, saving space, and being more reliable, they are also more complex to design and cannot maintain high-gain directional radiation on sharp curved surfaces. Summary of the Invention

[0004] This invention proposes an integrated antenna, which consists of a plastic shell composed of a parabolic head and a plateau-shaped bottom, and a conformal antenna attached to the plastic shell. This integrated antenna can maintain high-gain directional radiation on a sharply angled curved surface.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: An integrated antenna includes: a plastic shell and a conformal antenna attached to the plastic shell; the plastic shell consists of a parabolic head and a plateau-shaped bottom, the conformal antenna is attached to the parabolic head, the bottom of both ends of the conformal antenna are respectively hollowed out with the same parabolic curved surface, and the difference in length between the two ends of the conformal antenna along the direction of the parabolic head is 1 / 20λ to 1 / 8λ, the diameter of the end position of the parabolic head corresponding to the longer end of the two ends of the conformal antenna along the direction of the parabolic head is in the range of 1 / 20λ to 1 / 2λ, where λ represents the wavelength of the signal transmitted by the conformal antenna.

[0006] Furthermore, the aspect ratio of the parabolic head ranges from 1 to 10.

[0007] Furthermore, the feed position of the conformal antenna is set on the longer of the two ends of the conformal antenna.

[0008] Preferably, the length of the conformal antenna along the vertical direction on the parabolic head ranges from 1 / 2λ to 3 / 5λ.

[0009] More preferably, the conformal antenna has a frequency band ranging from 3 to 5 GHz.

[0010] Compared with the prior art, the present invention has the following beneficial effects.

[0011] This invention designs an integrated antenna, which consists of a plastic shell composed of a parabolic head and a plateau-shaped bottom, and a conformal antenna attached to the plastic shell. The antenna pattern converges, and it can also achieve high-gain directional radiation on relatively uneven surfaces, especially small conical surfaces. Attached Figure Description

[0012] Figure 1 This is one of the schematic diagrams of an integrated antenna structure provided in the embodiments of this application; Figure 2 This is a second schematic diagram of an integrated antenna structure provided in the embodiments of this application; Figure 3 This is one of the schematic diagrams of an integrated antenna mode provided in the embodiments of this application; Figure 4 This is a second schematic diagram of an integrated antenna mode provided in the embodiments of this application; Figure 5 This is the third schematic diagram of an integrated antenna mode provided in the embodiments of this application; Figure 6 This is the third schematic diagram of an integrated antenna structure provided in the embodiments of this application; Figure 7 This is a schematic diagram of the feeding position of an integrated antenna provided in an embodiment of this application; Figure 8 This is an antenna pattern of an integrated antenna provided in an embodiment of this application. Detailed Implementation

[0013] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0014] This application provides an integrated antenna, such as... Figure 1 As shown, it includes a plastic housing and a conformal antenna attached to the plastic housing. As is common knowledge, a conformal antenna is an antenna whose physical structure is attached to the surface of an existing object. This surface is usually not flat, but curved (such as an aircraft fuselage, missile casing, car roof, ship mast, etc.).

[0015] The plastic casing consists of a parabolic head and a plateau-shaped bottom. The conformal antenna is attached to the parabolic head. Identical parabolic surfaces are cut out at the bottom of both ends of the conformal antenna. The difference in length between the two ends of the conformal antenna along the direction of the parabolic head can range from 1 / 20λ to 1 / 8λ. The diameter corresponding to the longer end of the conformal antenna along the direction of the parabolic head can range from 1 / 20λ to 1 / 2λ. λ represents the wavelength of the signal transmitted by the conformal antenna.

[0016] Furthermore, the aspect ratio of the parabolic head can range from 1 to 10. The feed position of the conformal antenna can be located on the longer of the two ends of the conformal antenna. The length of the conformal antenna along the vertical direction on the parabolic head can range from 1 / 2λ to 3 / 5λ. The frequency band of the conformal antenna can range from 3 to 5 GHz, but other numerical ranges are also possible; this application does not limit the specific range.

[0017] The design process of the aforementioned integrated antenna is given below.

[0018] (1) Antenna resonance principle The radiation of an antenna is determined by its radiation mode. As a radiator, an antenna can radiate multiple forms of "modes". The modes that an antenna can form are determined by its structural dimensions.

[0019] For an ideal electric conductor of arbitrary shape with surface S, if there exists an incident electric field Ei, then the boundary conditions of the ideal conductor should satisfy: In the above formula, Represents the current on surface S The electric field of radiation This represents the tangential component of the electric field. The boundary conditions for the ideal conductor described above include: the tangential component of the electric field is zero at the conductor surface; the normal component of the magnetic field is zero at the conductor surface.

[0020] For the current in the conductor Its radiated power satisfies ,in It is the conjugate complex number of J, and satisfies the following condition when there is no internal resonance. ,but It is positive.

[0021] For Rayleigh: exist J Make Minimum, in order to obtain Find the value of and solve the following generalized eigenvalue equation: Considering , They are all real symmetric operators, and it is not difficult to prove mathematically that the eigenvalues... and characteristic current All have real values. Further investigation revealed that the characteristic currents of different modes have different values ​​with respect to the operator. , and Satisfies the following orthogonality relation: in, It is the Kronecker function (when m=n, ),otherwise Note that the characteristic current is normalized here using the R operator, i.e., ,express The radiated power is 1.

[0022] because Complex power P nn = Therefore, the net energy stored in the mode is represented by λn, and λn=0 means that the mode is in a resonant state.

[0023] In order to make the antenna resonate, =0. Therefore, for different modes, the total field of the above ideal electric conductor satisfies the following formula: That is, the far field of the feature pattern is orthogonal.

[0024] (2) Mode excitation principle of conductor characteristic modes The generation of modes stems from different antenna sizes. For antenna modes to exhibit different resonant modes at close frequencies, modes from different sources are required.

[0025] The concept can be simply understood as follows: antenna modes can be broadly classified into two categories: source mode coupling and inter-mode coupling. Source mode coupling describes how the excitation source (such as the feed port) interacts with the various characteristic modes of the antenna itself, and the mode is determined by the feed position of the antenna. Inter-mode coupling describes the energy exchange between different characteristic modes in the antenna, and the mode is determined by the structural dimensions.

[0026] For common antennas, bandwidth can be broadened by appropriately combining antenna modes, but constraints exist. In this theory, characteristic modes only describe all existing modes, and mode excitation is determined by mode importance. A decision is defined as follows: As shown in the above equation, the resonant frequency of an antenna is determined by its own size, the feeding location, and the surrounding environment. Imagine a wire of a specific length without a diameter, fed at an appropriate location; this will generate a resonant mode that can be excited. Similarly, if this same length of wire is bent, the original resonant mode frequency will change, and a new resonant mode will be formed.

[0027] For ordinary antennas, the simplest way to construct a beam-converging antenna is to use a traditional microstrip antenna design. This involves constructing a rectangular or circular microstrip antenna patch above a flat surface and creating a radiation pattern perpendicular to the patch surface. However, bending or wrapping the surface will change the basic resonant modes and create new ones. The superposition of these modes will significantly alter the radiation pattern, preventing it from converging.

[0028] (3) Integrated antenna design that coordinates the above source-mode coupling and inter-mode coupling According to the basic principles of antennas, the field of an antenna is formed by integrating the intensity and position of the point current. In other words, if an antenna is to form a more focused beam, the current in one of the directions is equivalent to being in the same direction.

[0029] Design an integrated antenna, such as Figure 2 As shown, it includes a plastic shell and a conformal antenna attached to the plastic shell; the plastic shell consists of a parabolic head and a plateau-shaped bottom, and the conformal antenna is attached to the parabolic head. The bottom ends of the conformal antenna each have identical parabolic curved surfaces cut out. Specifically, corresponding to... Figure 2 In the image, the yellow section is the conformal antenna, located at the pen cap position. Its maximum diameter at the bottom is approximately 8mm, contributing to the overall compact size of the product. The blue section is the plastic housing used for conformal antenna design. The example antenna operates at approximately 4GHz.

[0030] In this state, the antenna exhibits several different resonant modes, each with a different resonant frequency. Taking the resonant mode with the lowest resonant frequency, there are as follows: Figure 3 The four modes shown.

[0031] refer to Figure 3 The four modes mentioned above will be referred to as ①, ②, ③, and ④, respectively. Of these four modes, ① is the one we need to use, ② is the one we need to resist as much as possible, and ③ and ④ often interact with each other.

[0032] Continue to refer to Figure 3Modes ③ and ④ are generated by their structural dimensions, and their resonant wavelengths are approximately four times the total length of ③ or ④, respectively. Therefore, to deviate from the operating frequency band, ③ and ④ need to be of unequal length. At the same time, ① must remain unchanged, and the total length must be equal. Therefore, the antenna is not completely symmetrical on the left and right axes, but rather has an effect of one end being longer than the other.

[0033] like Figure 4 As shown, in addition to the four basic modes mentioned above, when power is introduced, two more modes generated by the power supply will appear: mode ⑤ and mode ⑥, which will be referred to as ⑤ and ⑥ respectively below.

[0034] refer to Figure 4 ⑤ and ⑥ are determined by the feed position. To offset ⑤ and ⑥ due to the antenna asymmetry, the antenna feed needs to be offset to one side in the middle of its total length. At this time, the frequencies of ⑤ and ⑥ will diverge. As shown in the figure, the frequency band of ⑤ is slightly higher than ①, while that of ⑥ is slightly lower than ①. Furthermore, because the frequencies of ③ and ④ are similar to those of ⑤ and ⑥, the patterns can be partially canceled out and not displayed.

[0035] For ②, the frequency manifestation is determined by the ratio of the antenna surface current. For antennas with asymmetry at both ends, the typical mode is a half-wavelength mode with the short end dimension twice that of the antenna. Its mode is as follows: Figure 5 As shown.

[0036] refer to Figure 5 At this point, only ① of the antenna can operate in the required frequency band. To further improve antenna performance, the ratio of the two stubs can be optimized so that for mode ①, the optimal feed position is basically located at the top of the yellow part (where the current is relatively strong). The advantage of doing this is that ③ and ④ can be better suppressed.

[0037] Thus, an integrated antenna with an asymmetric design was obtained.

[0038] In one application scenario of the aforementioned asymmetric design integrated antenna, such as Figure 6 As shown, an asymmetrical design was implemented. After debugging, one end was 14.3mm and the other end was 16.6mm. Simulation confirmed the existence of mode ①. This integrated antenna has three possible feed positions, all of which can successfully trigger mode ①, such as... Figure 7 As shown, the final choice was position a, where the feed eccentricity was 1mm on one side of 16.6mm, to suppress the emergence of other modes.

[0039] The antenna pattern of the aforementioned integrated antenna is as follows: Figure 8 As shown, Figure 8 The +y direction is the positive transmission direction, and the +z direction is the orientation of the antenna conformal pattern. Figure 8 It can be seen that the antenna pattern converges, and high-gain directional radiation can be achieved on relatively uneven surfaces, especially on small conical surfaces.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An integrated antenna, characterized in that, include: A plastic housing and a conformal antenna attached to the plastic housing; The plastic shell consists of a parabolic head and a plateau-shaped bottom. The conformal antenna is attached to the parabolic head. The bottom of both ends of the conformal antenna has the same parabolic curved surface cut out. The difference in length between the two ends of the conformal antenna along the direction of the parabolic head is in the range of 1 / 20λ to 1 / 8λ. The diameter of the end position of the parabolic head corresponding to the longer end of the conformal antenna along the direction of the parabolic head is in the range of 1 / 20λ to 1 / 2λ, where λ represents the wavelength of the signal transmitted by the conformal antenna.

2. The integrated antenna as described in claim 1, characterized in that, The aspect ratio of the parabolic head ranges from 1 to 10.

3. The integrated antenna as described in claim 1, characterized in that, The feed position of the conformal antenna is set on the longer of the two ends of the conformal antenna.

4. An integrated antenna as described in claim 1, characterized in that, The length of the conformal antenna along the vertical direction on the parabolic head ranges from 1 / 2λ to 3 / 5λ.

5. An integrated antenna as described in claim 1, characterized in that, The conformal antenna operates in the frequency band of 3 to 5 GHz.

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