Vertical polarization all-metal high-gain end-on-fire antenna based on annular unit and design method

Abstract

The invention discloses a vertical polarization all-metal high-gain end-on-fire antenna based on an annular unit and a design method. The vertical polarization all-metal high-gain end-on-fire antenna comprises parallel double lines which are separated in parallel up and down and are based on an air medium, transverse branch knots which are arranged at two sides of the parallel double lines in the length direction and are separated from each other, and a vertical conductor for connecting the upper and lower transverse branch knots; the transverse branches, the vertical conductors on the two sides and the corresponding parallel double-line parts form a plurality of annular units which are arranged at equal intervals, and each annular unit comprises a pair of vertical conductors, two pairs of transverse branches which correspond to each other up and down and the corresponding parallel double-line parts; the current directions of the upper and lower transverse branches of the annular unit are opposite, a radiation zero point is generated in the end-fire direction, end-fire radiation cannot be effectively generated, and the annular unit serves as a transmission part; the vertical conductors on the two sides have currents in the same direction, and effective radiation is generated in the end-fire direction and serves as a radiation part. The antenna provided by the invention can simultaneously realize high gain, high gain length ratio, stable end-fire radiation, low cost and easy assembly.

Description

Technical Field

[0001] The present invention relates to the technical field of periodic leaky-wave end-fire antennas, and in particular to an all-metal annular unit vertically polarized high-gain end-fire antenna using an air medium and a design method thereof. Background Art

[0002] Endfire antennas are widely used in long-distance wireless communications. To meet the demands of long-distance signal coverage and large-scale deployment within length constraints, stringent requirements are placed on antennas for high gain, high gain-to-length ratio, stable endfire radiation performance, and low cost and ease of assembly.

[0003] Periodic leaky-wave end-fire antennas have attracted considerable attention due to their high gain characteristics. They are primarily categorized into two types: dielectric substrate antennas and air-based antennas. While dielectric-based leaky-wave antennas are easy to fabricate, they suffer from unstable patterns and low gain-to-length ratios. Air-based leaky-wave antennas better meet the Hansen-Woodyard (HW) conditions, achieving high gain, a high gain-to-length ratio, and stable end-fire performance through dual-path coupling, all at a lower cost. However, they are difficult to assemble, and their gain improvement is limited when length is limited.

[0004] Therefore, how to optimize the structural process of air dielectric antennas, reduce assembly difficulty and break through the gain bottleneck under size limitations while maintaining high performance advantages remains a challenge. Summary of the Invention

[0005] The purpose of the present invention is to further improve the gain and solve the problem of large assembly errors in application scenarios with limited length, and to provide a vertically polarized high-gain end-fire antenna based on an all-metal ring unit using air medium and a design method. The antenna is a vertically polarized all-metal end-fire antenna based on a ring unit that can simultaneously achieve high gain, high gain-to-length ratio, stable end-fire radiation, low cost and easy assembly.

[0006] One object of the present invention is to provide a vertically polarized all-metal high-gain end-fire antenna based on an annular unit, comprising parallel double wires based on an air medium arranged in parallel and spaced apart from each other in the upper and lower directions, with mutually spaced lateral branches and vertical conductors connecting the upper and lower lateral branches arranged on both sides of the length direction of the parallel double wires; the lateral branches, the vertical conductors on both sides and the corresponding parallel double wire parts constitute a plurality of equally spaced annular units, each annular unit comprising a pair of vertical conductors, two pairs of corresponding upper and lower lateral branches and corresponding flat double wire parts; the current directions of the upper and lower lateral branches in the annular unit are opposite and cannot generate radiation in the end-fire direction, serving as the transmission part of the antenna; the current directions of the vertical conductors on both sides are the same, generating effective end-fire radiation, serving as the radiation part of the antenna.

[0007] Preferably, the antenna adopts a dual-port structure, with the two ports connected to the excitation and matching loads respectively, forming a dual-port periodic leaky-wave end-fire antenna, and a dual-port feeding structure is formed at both ends of the parallel double lines.

[0008] Preferably, a coaxial cable is used for dual-port feeding, and the coaxial cable is preferably a semi-steel cable.

[0009] Preferably, the transverse branches and the vertical conductors are of the same size and shape and are evenly spaced and arranged.

[0010] Preferably, the spacing distance P of the annular units is less than 0.5λ0.

[0011] Preferably, the antenna is fed by a single port and excited by the single port to form a single-port end-fire antenna. A single-port feeding structure is formed at one end of the parallel double wires, and the other end is open and not processed.

[0012] Preferably, a coaxial cable is used for single-port feeding, and the coaxial cable is preferably a semi-steel cable.

[0013] Another object of the present invention is to provide a design method for a vertically polarized all-metal high-gain end-fire antenna based on a ring unit, comprising the steps of:

[0014] Select the center frequency and determine the operating frequency band;

[0015] Design matching parallel double line parameters;

[0016] A ring unit structure that can be equivalent to a two-dimensional array is selected for high gain design;

[0017] Adjust the ring unit parameters and unit spacing to optimize the phase constant, aperture distribution, and suppress high-order harmonics;

[0018] Connect both sides of the antenna to coaxial cables, feed one side and connect the other side to the load to obtain a dual-port antenna;

[0019] Connect one side of the antenna to a coaxial cable for feeding, and keep the other side open to obtain a single-port antenna.

[0020] Theoretical analysis and simulation optimization are carried out to obtain the simulation optimization results of the dual-port / single-port antenna as the antenna processing parameters.

[0021] The vertically polarized all-metal high-gain end-fire antenna based on the ring unit of the present invention has the following characteristics:

[0022] 1. High Gain-to-Length Ratio: The antenna utilizes ring elements, equivalent to a two-dimensional array. This expands the scope for further improving gain and achieving a high gain-to-length ratio in length-constrained scenarios. Furthermore, the antenna can couple energy from two paths, providing a uniform aperture distribution and ensuring a high gain-to-length ratio.

[0023] 2. High gain: The antenna has a suitable phase constant, which can achieve high-gain end-fire radiation close to the theoretical limit.

[0024] 3. Stable end-fire radiation: The antenna uses an air dielectric transmission line operating in TEM mode, thus achieving stable end-fire radiation.

[0025] 4. Low cost and easy assembly: The antenna adopts an all-metal structure and has a more flexible processing and assembly method, so the cost is low and the assembly precision is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural diagram of the dual-port vertically polarized end-fire antenna based on the all-metal ring unit of the present invention.

[0027] Figure 2 It is a schematic diagram of the current distribution of the all-metal loop antenna unit of the present invention.

[0028] Figure 3 It is a structural diagram of a single-port vertically polarized end-fire antenna based on an all-metal ring unit of the present invention.

[0029] Figure 4 This is a comparison diagram of the simulated S parameters and gain of the dual-port vertically polarized end-fire antenna of the present invention.

[0030] Figure 5 This is a comparison diagram of the simulated S parameters and gain of the single-port vertically polarized end-fire antenna of the present invention.

[0031] Figure 6 It is the simulated E-plane (yoz plane) normalized radiation pattern of the dual-port vertically polarized end-fire antenna of the present invention at 5 GHz.

[0032] Figure 7 It is the simulated H-plane (xoy-plane) normalized radiation pattern of the dual-port vertically polarized end-fire antenna of the present invention at 5 GHz.

[0033] Figure 8 It is the simulated E-plane (yoz plane) normalized radiation pattern of the single-port vertically polarized end-fire antenna of the present invention at 5 GHz.

[0034] Figure 9 It is the simulated H-plane (xoy-plane) normalized radiation pattern of the single-port vertically polarized end-fire antenna of the present invention at 5 GHz. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] In an exemplary embodiment of the present application, it is a high-gain end-fire antenna with vertical polarization based on a ring unit and adopting air dielectric TEM mode transmission. It is made of an all-metal structure and consists of a radiating structure consisting of a two-wire part, an extended metal lateral branch part and a vertically placed conductor part, and is fed by a coaxial cable (such as a semi-steel cable).

[0037] In an exemplary embodiment of the present application, the dual-port vertically polarized end-fire antenna based on the all-metal ring unit may be a dual-port periodic leaky-wave end-fire antenna, such as Figure 1 As shown, it consists of an upper and lower double wire (separated by a distance of H), and vertical conductors on both sides of the upper and lower horizontal sides, and is fed by a coaxial cable (such as a semi-steel cable), wherein the vertical conductors on both sides are the radiation structure of the antenna, the parallel double wires of the air medium and the horizontal branches on both sides serve as the transmission structure, and the upper and lower horizontal branches are connected by vertically arranged conductors to realize the assembly of the upper and lower double wires. The horizontal branches, the vertical conductors on both sides and the corresponding double wire parts constitute the annular unit of the embodiment of the present application, and the length of the horizontal branch is W2 and the width is L2.

[0038] In an exemplary embodiment of this application, the vertical conductor structures on both sides utilize screws and copper pillars to form a ring-shaped unit structure with the upper and lower lateral branches. In specific embodiments, the vertical conductors on both sides are not particularly limited and can be integrally manufactured using metal processing techniques such as CNC to achieve the effect of connecting the upper and lower lateral branches.

[0039] In the exemplary embodiment of the present application, the structure of the all-metal ring antenna unit is as follows: Figure 2 As shown, it consists of a double-wire matrix (width W1), metal lateral branches extending on both sides of the length of the double-wire matrix, and vertically placed conductors. From the current distribution, it can be seen that the currents of the upper and lower metal lateral branches are opposite to each other, resulting in a radiation null in the end-fire direction and unable to effectively generate end-fire radiation. The conductors on both sides have currents in the same direction, which can generate effective radiation in the end-fire direction. Therefore, in the exemplary embodiments of the present application, the proposed antenna can be equivalent to a two-dimensional array participating in radiation.

[0040] In order to meet the phase constant of the end-fire radiation condition, in the exemplary embodiment of the present application, a TEM mode air-medium parallel two-wire transmission line is used as the feeding structure. Its phase constant is equal to the propagation constant k0 in the air and has non-dispersion characteristics, thereby ensuring the stability of the end-fire radiation pattern.

[0041] In the exemplary embodiments of this application, when radiating elements are loaded along a parallel dual-line period, the periodic structure introduces spatial harmonics. To avoid interference from higher-order harmonics, the spacing P between the ring elements in the present invention should be less than 0.5λ0. In this case, the zero-order spatial harmonic dominates, pointing in the end-fire direction, and does not generate grating lobes. By suppressing higher-order spatial harmonics, the antenna's radiation performance is guaranteed.

[0042] In the exemplary embodiments of this application, the radiating elements have a dual-path energy coupling mechanism. The first path is energy transmission via two parallel lines, where the energy gradually decreases over the transmission distance; the second path is derived from radiative coupling between elements in free space, where radiating elements farther from the feed port can obtain more spatially coupled energy.

[0043] In the exemplary embodiments of this application, the synergistic effect of the two coupling paths described above ensures uniform field distribution at the radiating aperture. By adjusting the parameters of the annular elements, both paths can be optimized, allowing each radiating element in the array to effectively participate in radiation, thereby achieving the antenna's high gain-to-length ratio.

[0044] In summary, when the antenna unit and array meet the above requirements and the two ports of the parallel double lines are connected to the excitation and matching loads respectively, the proposed dual-port all-metal vertically polarized ring unit antenna will be realized.

[0045] In the exemplary embodiment of the present application, the dual-port vertically polarized end-fire antenna based on the all-metal ring unit is similar to the single-port end-fire antenna structure. The structure of the single-port high-gain end-fire antenna is as follows: Figure 3 As shown, it is mainly composed of two layers of double wires, upper and lower, and conductors on both sides. It is fed by a coaxial cable (such as a semi-steel cable). The upper and lower parallel double wires are excited by a single port, and the other end is open and not processed. The single-port periodic leaky wave end-fire antenna is evolved from the dual-port periodic leaky wave end-fire antenna. Since the energy on the parallel double wires is gradually coupled by the conductors on both sides, the energy at the end of the transmission structure in the dual-port antenna is relatively weak. Therefore, the present invention replaces the terminal connection matching load method with the terminal open circuit method, simplifies the dual-port antenna into a single-port antenna, and further reduces the assembly complexity.

[0046] Figure 4 、 Figure 5 The comparison of the simulated S parameters and gains of the dual-port antenna and the single-port antenna is given. Figure 6 、 Figure 7 The normalized radiation patterns of the dual-port antenna on the E-plane and H-plane at 5GHz are given. Figure 8 、 Figure 9 The normalized radiation patterns of the single-port antenna on the E-plane and H-plane at 5 GHz are given. These results show that both the dual-port and single-port antennas achieve good radiation performance with high gain and good matching within the frequency band.

[0047] In an exemplary embodiment of the present application, a dual-port / single-port vertically polarized high-gain end-fire antenna based on a ring unit can be designed or manufactured using the following method.

[0048] (1) Select the center frequency and determine the operating frequency band, such as the center frequency is 5 GHz.

[0049] (2) Optimize the height H and width W1 of the parallel double lines to achieve a better match between the double lines;

[0050] (3) Design a dual-port antenna. Aiming at the high gain design goal, use an antenna ring unit and optimize the width L2 and length W2 of the lateral branches in the ring unit to achieve a suitable phase constant and aperture distribution.

[0051] (4) Select an appropriate unit spacing distance P, which is usually less than half a wavelength. If the impedance matching of the antenna is further considered, it can be selected as 0.25λ0. For example, the unit spacing P in this design is 0.25λ0.

[0052] (5) Connect both sides of the antenna to coaxial cables, feed one side with power, and connect the other side to the load to obtain a dual-port antenna;

[0053] (6) Connect one side of the antenna to a coaxial cable and open the other side without any other processing to obtain a single-port antenna, which simplifies the assembly and structure of the antenna.

[0054] (7) According to theoretical analysis and simulation optimization, the processing parameters are determined, and the simulation results of the dual-port and single-port antennas are obtained, such as Figure 4 、 Figure 5 As shown, they are:

[0055] Simulation S of dual-port end-fire antenna 11 The bandwidth is 16.6%, the maximum gain is 15.41dBi, and the 3dB gain bandwidth is 14.0%. 11 The bandwidth is 12.8%, the maximum gain is 15.74dBi, and the 3dB gain bandwidth is 14.6%.

[0056] The basic principles, main features and advantages of the present invention are shown and described above. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0057] The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and all changes that come within the meaning and range of equivalents of the claims are therefore intended to be embraced therein.

[0058] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A vertically polarized all-metal high-gain end-fire antenna based on a ring unit, characterized by: The antenna comprises an air-based parallel double wire arranged in parallel and spaced apart from each other in the upper and lower directions, with mutually spaced transverse branches and vertical conductors connecting the upper and lower transverse branches arranged on both sides of the length direction of the parallel double wire; the transverse branches, the vertical conductors on both sides and the corresponding parallel double wire parts constitute a plurality of equally spaced annular units; each annular unit comprises a pair of vertical conductors, two pairs of corresponding transverse branches in the upper and lower directions and a corresponding flat double wire part; the current directions of the upper and lower transverse branches in the annular unit are opposite and cannot generate radiation in the end-fire direction, thus serving as the transmission part of the antenna; the current directions of the vertical conductors on both sides are the same, generating effective end-fire radiation, serving as the radiation part of the antenna.

2. The vertically polarized all-metal high-gain end-fire antenna based on a ring unit according to claim 1, characterized in that: The antenna adopts a dual-port structure, with two ports connected to the excitation and matching load respectively, forming a dual-port periodic leaky-wave end-fire antenna, and a dual-port structure is formed at both ends of the parallel double lines.

3. The vertically polarized all-metal high-gain end-fire antenna based on a ring unit according to claim 2, characterized in that: A coaxial cable is used for dual-port feeding, and the coaxial cable is preferably a semi-steel cable.

4. The vertically polarized all-metal high-gain end-fire antenna based on a ring unit according to claim 1, characterized in that: The transverse branches and the vertical conductors are consistent in size and shape and are evenly spaced and arranged.

5. The vertically polarized all-metal high-gain end-fire antenna based on a ring unit according to claim 1, characterized in that: The spacing distance P of the annular units is less than 0.5λ0.

6. The vertically polarized all-metal high-gain end-fire antenna based on a ring unit according to claim 1, characterized in that: The antenna is fed by a single port and excited by the single port, forming a single-port leaky-wave end-fire antenna. A single-port feeding structure is formed at one end of the parallel double wires, and the other end is open and not processed.

7. The vertically polarized all-metal high-gain end-fire antenna based on a ring unit according to claim 6, characterized in that: The antenna uses a coaxial cable for single-port feeding, and the coaxial cable is preferably a semi-steel cable.

8. A design method for a vertically polarized all-metal high-gain end-fire antenna, characterized in that: Including steps: Select the center frequency and determine the operating frequency band; Design matching parallel double line parameters; A ring unit structure that can be equivalent to a two-dimensional array is selected for high gain design; Adjust the ring unit parameters and unit spacing to optimize the phase constant, aperture distribution, and suppress high-order harmonics; Connect both sides of the antenna to coaxial cables, feed one side and connect the other side to the load to obtain a dual-port antenna; Connect one side of the antenna to a coaxial cable for feeding, and keep the other side open to obtain a single-port antenna. Theoretical analysis and simulation optimization are carried out to obtain the simulation optimization results of the dual-port / single-port antenna as the antenna processing parameters.

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