阅读说明：本技术 一种基于色散媒质的频率扫描天线、控制方法及应用 (Frequency scanning antenna based on dispersion medium, control method and application ) 是由 张鹏飞 冯今又 雷帅帅 王荣娟 葛辉 许鑫 赵一豪 孙文博 于 2021-05-14 设计创作，主要内容包括：本发明属于天线技术领域,公开了一种基于色散媒质的频率扫描天线、控制方法及应用,包括色散斜劈媒质块和馈电阵列。色散斜劈媒质块覆盖于馈电阵列上且预留间隔。本发明利用色散斜劈媒质块产生的色散相移和斜坡产生的基础相移叠加后形成随频率变化的相位差。当相位差附加在常规均匀馈电阵列相邻单元上可以实现波束随频率扫描。当相位差附加在传统频扫天线时,可以实现对扫描角度的拓宽。进一步,色散媒质还可以将传统频扫天线中心频点一侧频带对应的扫描范围扩展至越过法线,且波束过零点驻波不会升高,解决了传统频扫天线在过零点处驻波突然升高的问题,提升了频扫范围内天线系统的整体口径利用效率。(The invention belongs to the technical field of antennas, and discloses a frequency scanning antenna based on a dispersion medium, a control method and application thereof. The dispersion wedge media blocks are covered on the feed array and are reserved with intervals. The invention forms the phase difference along with the frequency change after the dispersion phase shift generated by the dispersion wedge medium block and the basic phase shift generated by the slope are superposed. The beam sweep with frequency can be achieved when phase differences are added to adjacent elements of a conventional uniform feed array. When the phase difference is added to the conventional frequency-scanned antenna, the scan angle can be widened. Furthermore, the dispersion medium can expand the scanning range corresponding to the frequency band on one side of the central frequency point of the traditional frequency-swept antenna to cross the normal line, and the standing wave at the zero crossing point of the wave beam cannot rise, so that the problem that the standing wave of the traditional frequency-swept antenna suddenly rises at the zero crossing point is solved, and the utilization efficiency of the whole aperture of the antenna system in the frequency-swept range is improved.)

1. A dispersive medium based frequency scanning antenna, wherein the dispersive medium based frequency scanning antenna comprises:

a dispersion wedge media block and a feed array; the feed array can be a conventional uniform linear array or a frequency scanning array comprising a slow wave line structure; the dispersion wedge medium block covers the feed array, and a gap is reserved.

2. The dispersive media-based frequency scanning antenna of claim 1, wherein the dispersive wedge media block has a slope, the slope angle is denoted as α, the height of the bottom of the dispersive wedge media block above the feed array is denoted as hp _1, and the width is denoted as w.

3. The dispersive media-based frequency scanning antenna of claim 1, wherein the relative permittivity of the dispersive wedge media block is a function of frequency and is expressed as e_r(f) The additional phase difference generated by the dispersive wedge media block is as follows:

wherein the content of the first and second substances,andrespectively frequency f in the dispersive wedge media block₁、f₂Corresponding wave number, d is the distance between the feed array units, alpha is the slope angle of the dispersion wedge media block, epsilon_r(f₁)、ε_r(f₂) Respectively frequency f in the dispersive wedge media block₁、f₂Corresponding dielectric constant, k₀Is the wave number in free space;

and then according to the relation between the deflection angle of the wave beam in the free space and the phase difference among the units in the feed array:

wherein the content of the first and second substances,is a unit roomPhase difference theta is a beam deflection angle;

formula (II)And formulaEquivalently, the beam deflection angle generated by the phase difference caused by the dispersion wedge medium block can be obtained, as shown in the formula:

wherein, theta is a beam deflection angle generated by phase difference caused by the dispersion wedge medium block, and is related to frequency to form a beam frequency sweep effect.

4. The frequency-scanning antenna based on dispersive medium according to claim 1, wherein the feed array may be a conventional uniform linear array or a frequency-scanning array including a slow wave line structure, and the dispersive medium may make the conventional uniform array form a beam scanning effect, and may also widen the scanning range of the conventional frequency-scanning array to solve the problem of zero crossing of the beam.

5. The dispersion medium-based frequency-scanning antenna of claim 1, wherein the frequency-scanning effect based on the coverage of the medium block is applicable to both one-dimensional linear arrays and two-dimensional planar arrays.

6. A method for searching a target by an airborne early warning radar, which is characterized in that the airborne early warning radar uses the dispersion medium-based frequency scanning antenna of any one of claims 1-5.

7. A method for searching a target by using a ship-based early warning radar is characterized in that the method for searching the target by using the frequency scanning antenna based on the dispersive medium of any one of claims 1 to 5.

Technical Field

The invention belongs to the technical field of antennas, and particularly relates to a frequency scanning antenna based on a dispersion medium, a control method and application.

Background

At present: in the field of military communication, and when airborne and shipborne early warning radars search targets, the beam direction needs to be changed continuously. Early radar antennas were unable to meet the requirement for fast scanning by means of beam scanning that was achieved by continuous mechanical rotation, so mechanical scanning radars gradually exited from application. Electronically scanned antenna technology began to be applied to airborne radar. Typical electric scanning antennas include phase scanning and frequency scanning, among which frequency scanning antennas have the advantages of lower cost, simple structure, etc., and simple feeding, and the scanning of beams can be realized only by changing the feeding frequency.

The conventional leaky-wave frequency scanning antenna has the disadvantages that the scanning range is too small in a narrow frequency band range, and the inherent defects that standing waves are suddenly increased due to the same-phase superposition of reflection generated by all radiation gaps on a frequency point which leads a wave beam to point to the normal direction of a plane where the antenna is located exist. Although the scanning range is widened by people in the follow-up mode in a slow wave line mode, the inherent defects still cannot be solved, and normally-directed beams have to be abandoned when the scanning device is used, so that much inconvenience is brought to practical application.

Through the above analysis, the problems and defects of the prior art are as follows: the traditional leaky-wave frequency scanning antenna has an undersize scanning range in a narrower frequency band range, and has the inherent defect that standing waves are suddenly increased due to the same-phase superposition of reflection generated by all radiation gaps on a frequency point which leads a wave beam to point to the normal direction of a plane where the antenna is located.

The difficulty in solving the above problems and defects is: the size of the antenna is increased when the serpentine slow wave line passes through; and corresponding to the state that the wave beam points to the normal direction, the in-phase excitation of the radiation gap is needed in the feeder line, and at the moment, each radiation unit generates in-phase superposed reflection in the feeder line, so that the standing-wave ratio of the frequency point and the overall characteristics of the antenna are deteriorated.

The significance of solving the problems and the defects is as follows: a new beam scanning mechanism is established, the problem of in-phase superposition of reflected signals of the traditional frequency scanning antenna can be avoided, beam pointing of a zero crossing point is realized by introducing external additional phase difference, and the reflection problem is fundamentally solved. The wave beam scanning range of the traditional frequency scanning antenna on the designated bandwidth can be expanded, continuous angle scanning including the over-normal direction can be obtained, the matching is good, and convenience is provided for the use of the frequency scanning antenna. The wave beam passes zero, and the utilization efficiency of the whole aperture of the antenna system in the frequency scanning range is synchronously improved.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a frequency scanning antenna based on a dispersion medium, a control method and application.

The invention is thus realized, a frequency-scanning antenna based on a dispersive medium comprising:

the dispersion wedge medium block with gradient and the feed array;

the dispersion wedge medium block is covered on the feed array, and a gap is reserved between the dispersion wedge medium block and the feed array.

Further, the dispersion wedge medium block has a certain slope, the included angle of the slope is represented as alpha, the height from the bottom of the dispersion wedge medium block to the feed array is represented as hp _1, and the width of the dispersion wedge medium block is represented as w.

Further, the relative dielectric constant of the dispersion wedge medium block is a function epsilon changing with frequency_r(f)。

Furthermore, the electromagnetic waves radiated by different units of the feed array enter the dispersion wedge medium block through the free space to continue to propagate, and the original phase changes, and the additional phase difference generated by the dispersion wedge medium block among the units is as follows:

wherein the content of the first and second substances,andrespectively frequency f in the dispersive wedge media block₁、f₂Corresponding wave number, d is the distance between the feed array units, alpha is the slope angle of the dispersion wedge media block, epsilon_r(f₁)、ε_r(f₂) Respectively frequency f in the dispersive wedge media block₁、f₂Corresponding dielectric constant, k₀Is the wave number in free space;

and then according to the relation between the deflection angle of the beam in the free space and the phase difference between the units in the linear array:

wherein the content of the first and second substances,is the phase difference between units, theta is the beam deflection angle;

formula (II)And formulaEquivalently, the beam deflection angle generated by the phase difference caused by the dispersion wedge medium block can be obtained, as shown in the formula:

where θ is the beam deflection angle resulting from the phase difference caused by the dispersive wedge. The frequency sweep effect is constructed as a function of frequency.

Further, when the feed array adopts a traditional frequency-scanning antenna, the beam scanning depends on the phase difference between the units, and the phase difference is formed by overlapping two parts of the phase difference generated by the frequency-scanning feed array on different frequencies and the additional phase difference caused by the loaded dispersion wedge medium block. Thereby extending the scan range of the frequency scan feed array.

Furthermore, by adopting proper design, the dispersion medium can expand the scanning range corresponding to the frequency band on one side of the central frequency point of the traditional frequency scanning antenna to cross the normal line, the zero-crossing point position of the wave beam does not correspond to the reflection in-phase superposition electricity of the feed system, and the standing wave cannot rise. Therefore, the problem that standing waves of the traditional frequency scanning antenna suddenly rise at the zero-crossing point is solved. The utilization efficiency of the whole aperture of the antenna system in the frequency scanning range is further improved.

Furthermore, the method provided by the invention can be used for a one-dimensional linear array and a two-dimensional planar array.

Another object of the present invention is to provide a method for searching a target by an onboard early warning radar, which uses the dispersion medium-based frequency scanning antenna.

Another objective of the present invention is to provide a method for searching a target by using a shipboard pre-warning radar, which uses the dispersion medium-based frequency scanning antenna.

By combining all the technical schemes, the invention has the advantages and positive effects that: the dispersion and phase difference of adjacent radiation units caused by slope of the inclined plane make contribution to the generation of additional phase difference, and the scanning of the wave beam of the antenna system along with frequency can be realized to a greater extent. The antenna can be covered on a traditional frequency scanning antenna, and the beam scanning angle range in a specified frequency band can be widened. Furthermore, when the slope of the inclined plane reaches a certain value, the scanning range corresponding to the frequency band on one side of the central frequency point can be expanded to the other side including the zero crossing point, and the standing wave can not rise, so that the inherent defect that the standing wave suddenly rises at the zero crossing point of the traditional frequency scanning antenna is overcome. The utilization efficiency of the whole aperture of the antenna system in the frequency scanning range is improved.

Drawings

In order to more clearly illustrate the technical solution of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly described below, and it is apparent that the drawings described below are only some embodiments of the present application, and the feed array in this embodiment adopts a conventional frequency-scanning antenna based on waveguide slow-wave lines. For a person skilled in the art, it is possible to derive other figures from these figures without inventive effort.

Fig. 1 is a schematic structural diagram of a frequency-scanning antenna based on a dispersive medium according to an embodiment of the present invention.

Fig. 2 is a front view of a frequency-swept dispersive medium-based antenna according to an embodiment of the present invention.

Fig. 3 is a top view of a frequency-swept dispersive medium-based antenna provided by an embodiment of the present invention.

Fig. 4 is a partially enlarged view of the non-feeding terminal provided in the embodiment of the present invention.

Fig. 5 is a partially enlarged view of a feeding terminal provided in an embodiment of the present invention.

Fig. 6 is a graph of simulation results of frequency-standing waves provided by an embodiment of the present invention.

Fig. 7 is a graph of simulation results of frequency-standing waves of a non-dispersive wedge mass according to an embodiment of the present invention.

Fig. 8 is a diagram of a simulation result of a scan angle-gain pattern according to an embodiment of the present invention.

Fig. 9 is a graph of the simulation result of the scan angle-gain pattern of a non-dispersive wedge medium provided in the embodiment of the present invention.

In the figure: 1. a feed array in the form of a waveguide slow wave line; 2. a dispersive wedge media block; 1.1, a linear waveguide segment; 1.2, an elbow.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Aiming at the problems in the prior art, the invention provides a frequency scanning antenna based on a dispersion medium, a control method and application. The working principle of the traditional frequency scanning antenna is as follows: the linear array is a leaky-wave linear array, one end of the linear array is excited, the other end of the linear array is absorbed, the excited electromagnetic wave is transmitted and radiated through a gap, and finally the rest energy is absorbed by a load, so that a traveling wave structure is formed. Taking a linear array without tapering as an example, the amplitude of each radiating element current in the linear array is equal, the phase needs to be changed in sequence, and the radiating elements are formed in adjacent array elementsThe phase difference of (1). When excited at a certain frequency, the phase differenceThat is, when all array elements are excited in phase, the equiphase plane is a plane parallel to the line where the array is located, and at this time, the main beam of the array directional diagram points to the normal direction of the line where the array is located. When the frequency deviates and the phase differenceWhen the current phase is not 0, the current phase of each radiation unit is sequentially increased, so that the equiphase plane is inclined and is not parallel to the straight line of the array, and an included angle is formed between the maximum radiation direction of the far field and the normal direction of the straight line of the array. As the feed frequency increases, the wavelength decreases and the geometrical length between adjacent elements in the linear array does not change, which causes phase differences between adjacent elementsGradually increasing to further enable the inclination angle of the equiphase surface radiated by each array element to be larger and larger, and finally enabling the included angle formed by the beam pointing direction in the maximum radiation direction of the array and the normal direction of the straight line where the array is located to be gradually increased; conversely, the angle is gradually decreased as the frequency is decreased. Thus, by changing the frequency of the feed source, the beam scanning effect can be realized.

The frequency scanning antenna based on the dispersion medium utilizes the dispersion characteristic and the geometric structure of the loaded medium to correspondingly form an additional phase difference on each radiation unit corresponding to the external space of the antennaAnd this additional phase difference varies with frequency. At the moment, the inter-unit phase difference for realizing beam scanning is formed by overlapping two parts of phase difference existing among the units in the feed array and additional phase difference caused by the loaded dispersion wedge medium block, and the effect of expanding the antenna beam scanning range without changing the feed source frequency range can be achieved.

The present invention will be described in detail below with reference to the accompanying drawings.

As shown in fig. 1, fig. 2, fig. 3, fig. 4 and fig. 5, the frequency scanning antenna based on dispersive medium according to the embodiment of the present invention includes a feed array 1 in the form of a waveguide slow wave line, and a dispersive wedge medium block 2. The feed array 1 in the form of a waveguide slow wave line consists of n slotted linear waveguide sections 1.1 and n-1 elbows 1.2 connected with the linear waveguide sections, wherein the elbows 1.2 are 180-degree elbows with cut angles, and the slotted gaps on the linear waveguide sections 1.1 have different lengths and different inclination angles; the dispersion wedge medium block 2 covers the gap opened by the feed array 1 in the form of a waveguide slow wave line and has a certain height from the gap.

The feed array 1 in the form of a waveguide slow wave line consists of n slotted linear waveguide sections and n-1 elbows connected with the linear waveguide sections, wherein the elbows are 180-degree elbows with cutting angles;

the dispersion wedge medium block 2 covers the gap opened by the feed array 1 in the form of a waveguide slow wave line, and a gap is reserved between the dispersion wedge medium block and the gap.

The length and the inclination angle of the gaps formed by the n slotted linear waveguide sections are different, the n slotted linear waveguide sections are used for controlling the amplitude distribution of the radiation current of each unit to realize the beam tapering effect, the specific size is designed according to Taylor distribution followed by the radiation current of the gaps, and the distance between the gaps is represented as d.

The dispersion wedge medium block has a certain gradient, the included angle of the gradient is represented as alpha, the height from the bottom of the dispersion wedge medium block to the feed array is represented as hp _1, and the width of the dispersion wedge medium block is represented as w.

The relative dielectric constant of the dispersion wedge mass is a function epsilon varying with frequency_r(f)。

Electromagnetic waves radiated by each unit in the feed array enter the dispersion wedge medium block through a free space to be continuously propagated, the original phase is changed, and the additional phase difference generated by the dispersion wedge medium block among the slot units is as follows:

wherein the content of the first and second substances,andrespectively frequency f in the dispersive wedge media block₁、f₂Corresponding wave number, d is the feed array element pitchAlpha is the gradient angle of the dispersion wedge medium block, epsilon_r(f₁)、ε_r(f₂) Respectively frequency f in the dispersive wedge media block₁、f₂Corresponding dielectric constant, k₀Is the wave number in free space;

and then according to the relation between the deflection angle of the beam in the free space and the phase difference between the units in the linear array:

wherein the content of the first and second substances,is the phase difference between units, theta is the beam deflection angle;

formula (II)And formulaEquivalently, the beam deflection angle generated by the phase difference caused by the dispersion wedge medium block can be obtained, as shown in the formula:

where θ is the beam deflection angle resulting from the phase difference caused by the dispersive wedge.

The phase difference between units for realizing beam scanning is formed by superposing two parts, namely the phase difference generated on a radiation gap when a feed array in the form of a waveguide slow wave line per se propagates different frequencies at the same distance and the additional phase difference caused by a loaded dispersion wedge medium block.

When scanning in a large angle range is achieved by using less frequency spectrum resources, a waveguide crack structure in a slow wave line form is often adopted, however, a large number of necessary 180-degree elbows exist in the structure, and the reflection is inevitably generated in the transmission process of electromagnetic waves, so that the antenna is in a corner cut form, and the total reflection is counteracted by introducing multiple reflections in a local part by adjusting the size of the corner cut, so that the standing wave of the antenna is reduced.

In order to further expand the scanning range of the antenna, the invention introduces an additional phase difference between units in space by adopting a mode of loading a dispersion oblique-splitting medium block with a slope, and the additional phase difference is generated by two factors of dispersion characteristics and slope of the medium, so that the beam scanning range can be expanded to a greater degree. The distance between the bottom of the medium block and the feed array is adjusted by optimization, so that the propagation of the electromagnetic wave is matched in space.

In the conventional frequency scanning antenna, no matter what form, a large standing wave suddenly appears at a frequency position corresponding to the normal direction of the surface where the wave beam points to the antenna due to the in-phase superposition of the slot reflection, so that the antenna cannot use a maximum gain frequency area pointing to the normal direction, and the aperture utilization efficiency of the antenna is limited. In order to avoid the problem, the invention utilizes the characteristic that the scanning range is expanded by the dispersion medium with the slope, and further leads the scanning range corresponding to the frequency band at one side of the central frequency point to cross to the other side including the normal direction of the plane where the antenna is positioned without rising the standing wave, thereby ensuring the continuity of positive and negative scanning angles in the azimuth direction. At the moment, the wave beam frequency scanning area crosses the normal direction, and the aperture utilization rate in the whole frequency band is improved.

The length dimension of the feed array 1 in the form of a waveguide slow wave line is the sum of the widths of n waveguides and the spacing "d" of n-1 waveguides. The chamfer cut depth of the bend 1.2 is expressed as β, preferably 20 deg.

The thickness of the dispersive wedge medium block 2 on the side close to the feeding end is represented by h1, preferably 1mm, the thickness on the side far away from the feeding end is represented by h1+ h2, and h2 is the height difference of the two ends.

The length of the dispersion wedge media block 2 is + d of the length of the feed array 1 in the form of a waveguide slow wave line, the distance between the left end and the right end of the dispersion wedge media block and the left end and the distance between the left end and the right end of the feed array 1 in the form of the waveguide slow wave line are d/2 respectively, at the moment, the slope included angle alpha of the slope obtained through the length and the height difference is 9deg, and the width of the media block is represented as w. The height of its bottom from the feed array 1 in the form of a waveguide slow wave line is denoted hp _ 1.

The dispersion characteristics of the dispersive, wedge media block 2 are expressed as a function of frequency with respect to its relative dielectric constant, preferably er (f) 10 f-139.

The technical effects of the present invention will be further described in detail in connection with simulation experiments

As shown in fig. 6, 7, 8 and 9, simulation calculation was performed in the range of 14.55GHz to 14.99GHz using electromagnetic simulation software.

Fig. 6 is a graph of the simulation result of frequency-standing wave of the present invention, as shown in the figure, the standing wave ratio is less than 1.5 in the full frequency band, which indicates that the antenna matching performance is good, and the scanning range is effectively usable including the zero crossing point.

Fig. 7 is a graph showing the simulation result of frequency-standing wave of a comparative sweep antenna using the same feed array without adding the dispersive wedge media block, as shown in the figure, the standing-wave ratio in the full frequency band is less than 1.5, which is similar to the simulation result of the present invention, and it is demonstrated that the loaded dispersive wedge media block in the present invention does not negatively affect the feed array itself.

Fig. 8 is a diagram of a simulation result of a scanning angle-gain directional diagram of the present invention, as shown in the figure, the abscissa is an azimuth angle in degrees, and the ordinate is a normalized achievable gain in dB, and 12 sets of data having an interval of 0.04GHz within a range of 14.55GHz to 14.99GHz are shown in the figure. The beam pointing is-18 at 14.55GHz, 17 at 14.99GHz, and the scan angle changes by 35 over the full frequency band.

Fig. 9 is a graph of the simulation results of the scan angle-gain pattern of a contrast frequency-scanned antenna using the same feed array without the addition of the dispersive wedge media block, in which 12 sets of data at 0.04GHz intervals in the range of 14.55GHz to 14.99GHz are shown. The beam pointing is-31.4 ° at 14.55GHz, -1.2 ° at 14.99GHz, and the scan angle varies by 30.2 ° over the full frequency band.

It can be seen that the antenna can realize continuous scanning of-18-17 degrees including zero crossing points in a frequency band of 14.55 GHz-14.99 GHz, and has good matching, the scanning angle changes 35 degrees in 2.979% of relative bandwidth, and the scanning range is larger than that of a contrast frequency scanning antenna without a dispersive wedge medium block.

In the description of the present invention, "a plurality" means two or more unless otherwise specified; the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "head", "tail", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The above description takes the conventional frequency-scanned antenna based on the waveguide slow wave line as an example of the feed array, and the frequency-scanned antenna based on other structures is within the protection range as the conventional uniform feed array.

The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the invention, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the invention as defined by the appended claims.