Single-conductor bent line end-on-fire antenna based on air medium and design method

Abstract

The invention discloses a single-conductor bent line end-on-fire antenna based on an air medium and a design method, the single-conductor bent line end-on-fire antenna is composed of a bent line structure formed by bending a metal strip by 90 degrees according to a preset period, the bent line structure is arranged on one side of a floor, the X direction of the bent line structure is perpendicular to the floor, and the X direction of the bent line structure is perpendicular to the floor. The bent line structure serves as a feeder line and also serves as a radiation unit, the X-direction metal strip forms a transmission unit, and the Y-direction metal strip forms a radiation unit; and the floor is used for reflecting the backward radiation wave beam generated by the bending line structure through the floor to form a wave beam in an end-fire direction. The antenna is a bent line end-on-fire antenna which is miniaturized, low in profile, high in gain, high in gain length ratio, low in cost and easy to assemble, the structure is simple, machining is easy, the phase constant can be adjusted through two key structure parameters, the phase constant can meet a certain relation through two-dimensional regulation and control, and miniaturization and high gain can be achieved at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of end-fire antennas, and in particular to an air-medium-based single-conductor meander-line end-fire antenna and a design method thereof. Background Art

[0002] End-fire antennas, due to their unique performance, have found widespread application in fields such as satellite communications and radar detection. Existing end-fire antennas include Yagi antennas, log-periodic antennas, surface plasmon antennas, and periodic leaky-wave antennas. With the advancement of communication technology, the demand for end-fire antennas is increasing.

[0003] To achieve large-scale deployment while taking into account limited installation space, antennas must be miniaturized and easily fabricated. To meet the demands of long-distance wireless communications and achieve wider coverage, high gain is also a required performance characteristic. However, achieving these characteristics simultaneously, along with miniaturization, ease of fabrication, and high gain, remains a challenge for existing end-fire antennas. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings and defects of the prior art by providing a single-conductor, air-based meanderline end-fire antenna and design method. This approach aims to address the current difficulty in achieving miniaturization, easy-to-process structure, and high-gain performance in end-fire antennas. The antenna of the present invention is a miniaturized, low-profile, high-gain, high-gain-to-length ratio, low-cost, and easy-to-assemble meanderline end-fire antenna. It features a simple and easily processed structure, and its phase constant can be adjusted by two key structural parameters. This two-dimensional control allows the phase constant to satisfy a specific relationship, enabling both miniaturization and high gain.

[0005] One object of the present invention is to provide a single-conductor meander-line end-fire antenna based on an air dielectric. The antenna comprises a meander-line structure formed by bending a metal strip 90 degrees according to a preset period. The meander-line structure is arranged on one side of a floor with its X-direction perpendicular to the floor. The meander-line structure serves as both a feeder and a radiation element. The X-direction metal strip constitutes a transmission element, and the Y-direction metal strip constitutes a radiation element. The floor is configured to reflect the back-radiated beam generated by the meander-line structure through the floor to form an end-fire beam.

[0006] The phase constant of the single conductor meander line end-fire antenna is determined by the radiation unit length S x and transmission unit length S y To regulate.

[0007] Wherein, the radiation unit length S x and transmission unit length S y Control and meet the following conditions:

[0008] β×Sy =k0×(S x +S y )-π;

[0009] Where β is the propagation constant of the antenna, k0 is the wave number in free space, and there is a phase loading of π between adjacent radiating elements due to physical bending.

[0010] When the single-conductor meander line end-fire antenna realizes back radiation, its phase constant satisfies the following conditions:

[0011] β=-k0.

[0012] When the length of the meander line structure along the backscatter direction is L, the phase constant satisfies the following conditions, satisfying the reverse Hansen-Woodyard condition to achieve higher gain backscatter radiation:

[0013]

[0014] When the meander line structure is composed of N units along the back-firing direction, the meander line structure achieves back-firing when the structural parameters of the meander line meet the following conditions. The overall antenna achieves end-fire radiation through reflection from the floor:

[0015]

[0016] Another object of the present invention is to provide a method for designing a single-conductor meander-line end-fire antenna, the method comprising the following steps:

[0017] Select the center frequency and determine the operating frequency band;

[0018] Design a meander line structure. Based on the phase constant characteristics of the antenna, bring in the back radiation condition and the reverse Hansen-Woodyard condition to calculate the radiation unit length S of the meander structure. x and transmission unit length S y The value range of

[0019] According to the reverse Hansen-Woodyard condition, S x and S y The relationship between them is analyzed, and the radiation characteristics of the meander line structure are analyzed. The directivity coefficients of the radiation unit array and the transmission unit array in the end-fire direction and their differences are calculated.

[0020] According to the maximum difference, the radiation unit length S x and transmission unit length S y Determine the radiation unit length S within the value range of x and transmission unit length S yThe value of

[0021] According to the matching requirements, the width S of the metal strip constituting the bending line structure is determined w and the length F of the transmission line portion near the floor y ;

[0022] According to the radiation unit length S x and transmission unit length S y The value of the metal strip width S w and the length F of the transmission line portion near the floor y Processing the antenna.

[0023] Among them, the radiation unit length S of the bent structure is obtained x and transmission unit length S y Within the range of , there are multiple solutions that can enable the radiator of the meander line structure to achieve back radiation and then form end-fire radiation after being reflected by the floor.

[0024] The larger the difference is, the smaller the impact of the non-ideal radiation caused by the transmission unit on the back radiation is, and the corresponding value is S x and S y The optimal solution of .

[0025] The antenna of the present invention has the following innovative features:

[0026] 1. Miniaturization: The antenna has a two-dimensional controllable phase constant characteristic, which enables a smaller antenna size.

[0027] 2. Low profile: The overall profile height of the antenna is the diameter of the metal strip, and it has a low profile design feature.

[0028] 3. High gain: Adjust the antenna phase constant to meet the reverse Hansen-Woodyard condition to form high-gain radiation.

[0029] 4. High gain-length ratio: The phase constant satisfies the reverse Hansen-Woodyard condition and has a uniform aperture distribution.

[0030] 5. Low cost and easy processing: The antenna is an all-metal single conductor structure and can be made by processing metal strips. The raw material price is low and the processing steps are simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the meander line end-fire antenna of the present invention.

[0032] Figure 2 yes Figure 1 Enlarged plan view of the portion marked by the dotted line.

[0033] Figure 3 It is a schematic diagram of the working principle of the meander line end-fire antenna of the present invention.

[0034] Figure 4 Schematic diagram of the directivity coefficients of the radiating element array and the transmitting element array in the end-fire direction and their differences when the number of elements N is 8 for the meander line end-fire antenna of the present invention;

[0035] Figure 5 Schematic diagram of S parameters and gain of the simulated and tested meander line end-fire antenna of the present invention.

[0036] Figure 6 The E-plane (XOY-plane) radiation pattern of the meander line end-fire antenna of the present invention simulated and tested at 2.45 GHz.

[0037] Figure 7 The H-plane (YOZ-plane) radiation pattern of the meander line end-fire antenna of the present invention simulated and tested at 2.45 GHz. DETAILED DESCRIPTION

[0038] 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.

[0039] In the exemplary embodiments of the present application, Figure 1 、 Figure 2 As shown, the meander line end-fire antenna can be composed of a meander line structure formed by bending a metal strip 90 degrees at a certain period; the meander line structure is arranged on one side of the floor, with its X direction perpendicular to the floor. The floor has an excitation end connected to the feed transmission line near the floor end of the meander line structure. In an exemplary embodiment of the present application, the meander line structure acts as both a feed line and a radiating element, such as Figure 3 As shown, it can be divided into a radiation unit along the X axis and a transmission unit along the Y axis. The phase constant of the antenna is determined by the length of the radiation unit S. x and transmission unit length S y Control and meet the following conditions:

[0040] β×S y =k0×(S x +S y )-π;

[0041] Where β is the propagation constant of the antenna, k0 is the wave number in free space, and there is a phase loading of π between adjacent radiating elements due to physical bending.

[0042] Due to the presence of the floor, the end-fire beam can be formed by the back-radiated beam reflected by the floor, so the beam generated by the bend line needs to point in the back-fire direction.

[0043] For ordinary arrays, in order to achieve back radiation, the phase constant should satisfy:

[0044] β=-k0

[0045] Substituting this condition into the above expression, we can get:

[0046]

[0047] To achieve higher-gain back radiation, the phase constant should satisfy the reverse Hansen-Woodyard condition. This means adding a uniformly graduated leading phase to the uniformly graduated phase of a conventional array to improve the array's directivity. In this case, the phase constant satisfies the following conditions:

[0048]

[0049] Where L is the length of the bending line along the backscatter direction, which can be expressed as (N-1) times S in an N-element array. y .

[0050] Substituting this condition into the expressions of phase constant and structural parameters, we can obtain:

[0051]

[0052] In summary, when the number of units is determined, the structural parameters of the bending line have a certain range of values, namely:

[0053]

[0054] And the phase constant is also related to the parameter S x and S y When the structure meets the above value range, the meander line can achieve back radiation, and through the reflection effect of the floor, the overall antenna can achieve end-fire radiation.

[0055] Compared with ordinary arrays, arrays that meet the reverse Hansen-Woodyard condition not only have higher gain but also smaller size. Therefore, in order to achieve the optimal solution, the reverse Hansen-Woodyard condition must be met. At the same time, the radiation characteristics of the antenna are calculated to obtain the difference in directivity coefficients between the radiating element array and the transmission element array in the back-reflection direction. The larger the difference, the smaller the impact of the non-ideal radiation caused by the transmission element on the back-reflection direction. The corresponding value is S x and S y The other antenna parameters are selected through parameter analysis to analyze their impact on matching, gain, and radiation pattern. Optimization design is performed in HFSS to select the optimal antenna parameters.

[0056] In addition, in order to explore the optimal solution for structural parameters that maximizes gain, an exemplary embodiment of the present application also proposes a design method for a meander line end-fire antenna, comprising the following steps:

[0057] (1) Select the center frequency and determine the operating frequency band.

[0058] In this design example, the center frequency is selected as 2.45 GHz.

[0059] (2) Taking 8 units as an example, the meander line structure is designed. According to the phase constant characteristics of the antenna, the back radiation condition and the reverse Hansen-Woodyard condition are introduced to calculate the radiation unit length S x and transmission unit length S y The value range of

[0060] At this time, there are multiple sets of solutions for the structural parameters, all of which can enable the meander line radiator to achieve back radiation and then reflect through the floor to form end-fire radiation.

[0061] (3) To achieve the optimal solution, S is obtained according to the reverse Hansen-Woodyard condition. x and S y The relationship between them is analyzed, and the radiation characteristics of the bending line are analyzed. The directivity coefficients of the radiation unit array and the transmission unit array in the end-fire direction and their differences are calculated, such as Figure 4 As shown, when S x The difference is the largest when 25mm is selected, so S is selected in this design example. x =25mm, S y =14mm.

[0062] (4) To achieve better matching;

[0063] In this design example, select S w 3mm, F y It is 12.5mm.

[0064] (5) Based on the values ​​of the structural parameters obtained from the above simulation and theoretical analysis, the designed antenna is processed and then verified.

[0065] According to the antenna design method of the embodiment of the present invention, the simulation and test results of the designed antenna S parameters and end-fire gain are as follows: Figure 5 As shown in the figure, the operating frequency bands of the simulation and test are 2.40-2.50GHz and 2.37-2.50GHz respectively, and the maximum end-fire gains are 11.9dBi and 12.0dBi respectively. At the same time, the antenna obtains a stable end-fire pattern near the center frequency, as shown in the figure. Figure 6 、 Figure 7 There is good agreement between the simulation results and the test results.

[0066] 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.

[0067] 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.

[0068] 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 single conductor meander line end-fire antenna based on air dielectric, characterized in that: The device comprises a meander line structure formed by bending a metal strip 90 degrees according to a preset period. The meander line structure is arranged on one side of the floor, with its X direction perpendicular to the floor. The meander line structure serves as both a feeder and a radiation unit. The metal strip in the X direction constitutes a transmission unit, and the metal strip in the Y direction constitutes a radiation unit. The floor is used to reflect the back-radiated beam generated by the meander line structure through the floor to form an end-fire beam.

2. The single-conductor meander line end-fire antenna based on air dielectric according to claim 1, characterized in that: The phase constant of the single conductor meander line end-fire antenna is determined by the radiation element length S x and transmission unit length S y To regulate.

3. The single-conductor meander line end-fire antenna based on air dielectric according to claim 2, characterized in that: The radiation unit length S x and transmission unit length S y Control and meet the following conditions: β×S y =k0×(S x +S y )-π; Where β is the propagation constant of the antenna, k0 is the wave number in free space, and there is a phase loading of π between adjacent radiating elements due to physical bending.

4. The single-conductor meander line end-fire antenna based on air dielectric according to claim 3, characterized in that: When the single-conductor meander line end-fire antenna realizes back radiation, its phase constant satisfies the following conditions: β＝-k0。 5. The single-conductor meander line end-fire antenna based on air dielectric according to claim 4, characterized in that: When the length of the meander line structure along the backscatter direction is L, the phase constant satisfies the following conditions, satisfying the reverse Hansen-Woodyard condition to achieve highly directional backscattering:

6. The single-conductor meander line end-fire antenna based on air dielectric according to claim 5, characterized in that: When the meander line structure is composed of N units along the back-firing direction, the meander line structure realizes back-firing when the structural parameters of the meander line meet the following conditions. The overall antenna realizes end-fire radiation due to the reflection effect of the floor:

7. A method for designing a single-conductor meander line end-fire antenna, for designing the single-conductor meander line end-fire antenna according to any one of claims 1 to 6, characterized in that: The following steps are involved: Select the center frequency and determine the operating frequency band; Design a meander line structure. Based on the phase constant characteristics of the antenna, bring in the back radiation condition and the reverse Hansen-Woodyard condition to calculate the radiation unit length S of the meander structure. x and transmission unit length S y The value range of According to the reverse Hansen-Woodyard condition, S x and S y The relationship between them is analyzed, and the radiation characteristics of the meander line structure are analyzed. The directivity coefficients of the radiation unit array and the transmission unit array in the end-fire direction and their differences are calculated. According to the maximum difference, the radiation unit length S x and transmission unit length S y Determine the radiation unit length S within the value range of x and transmission unit length S y The value of According to the matching requirements, the width S of the metal strip constituting the bending line structure is determined w and the length F of the transmission line portion near the floor y ; According to the radiation unit length S x and transmission unit length S y The value of the metal strip width S w and the length F of the transmission line portion near the floor y Processing the antenna.

8. The design method of a single-conductor meander line end-fire antenna according to claim 7, characterized in that: The radiation unit length S of the bent structure is obtained x and transmission unit length S y Within the range of , there are multiple solutions that can enable the radiator of the meander line structure to achieve back radiation and then form end-fire radiation after being reflected by the floor.

9. The design method of a single-conductor meander line end-fire antenna according to claim 7, characterized in that: The larger the difference is, the smaller the impact of the non-ideal radiation caused by the transmission unit on the back radiation is, and the corresponding value is S x and S y The optimal solution of .

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