阅读说明：本技术 一种基于相位分解的液晶阵列天线波束成型与自适应控制方法 (Liquid crystal array antenna beam forming and self-adaptive control method based on phase decomposition ) 是由 雷东 于 2020-05-18 设计创作，主要内容包括：本发明涉及通信及算法领域,具体为一种基于相位分解的液晶阵列天线波束成型与自适应控制方法,包括如下步骤,S1、给定所期望的阵列天线的辐射方向图函数；S2、通过对给定方向图函数进行逼近,确定每一阵元的馈电权重矢量；S3、对每一个在阵列平面上进行相位分解,确定某一波束指向所对应的相位分解阵元分布；S4、通过天线的驱动系统实现相位分解阵元中液晶偏转状态的阵列分布进而实现所期望的阵列天线辐射方向图。本发明形成针对液晶阵列天线和其它超材料阵列天线波束合成与指向控制的一种普遍方法。(The invention relates to the field of communication and algorithm, in particular to a liquid crystal array antenna beam forming and self-adaptive control method based on phase decomposition, which comprises the following steps of S1, giving a radiation pattern function of an expected array antenna; s2, determining the feeding weight vector of each array element by approximating the given directional diagram function (ii) a S3, for each Performing phase decomposition on the array plane, and determining the distribution of phase decomposition array elements corresponding to a certain beam direction; and S4, realizing the array distribution of the liquid crystal deflection state in the phase decomposition array element through the driving system of the antenna so as to realize the expected array antenna radiation pattern. The invention forms beam forming and pointing control for liquid crystal array antennas and other metamaterial array antennasA general method of (1).)

1. A liquid crystal array antenna beam forming and self-adaptive control method based on phase decomposition is characterized by comprising the following steps,

s1, giving a radiation pattern function of a desired array antenna;

s2, determining the feeding weight vector of each array element by approximating the given directional diagram function；

S3, for eachPerforming phase decomposition on the array plane, and determining the distribution of phase decomposition array elements corresponding to a certain beam direction;

and S4, realizing the array distribution of the liquid crystal deflection state in the phase decomposition array element through the driving system of the antenna so as to realize the expected array antenna radiation pattern.

2. The method of claim 1, wherein the method comprises: in step S3The component sizes of the array element radiation fields Eij in the two corresponding phase decomposition units on the x axis and the y axis are realized by adjusting the deflection degree of the liquid crystal in the phase decomposition array elements.

3. The method of claim 2, wherein the method comprises: the adjustment of the degree of liquid crystal deflection includes applying an electric field and controlling the change in the magnitude thereof, so that liquid crystal molecules in the polarized liquid crystal material are deflected to different degrees.

4. The method of claim 1, wherein the method comprises: step S4 includes determining each of the phase-resolved array elements by applying a voltage drive signal to each of the phase-resolved array elements to effect an array distribution of liquid crystal deflection states in the phase-resolved array elementsThe corresponding magnitude values on the two decomposition units; and the radiation pattern of the array antenna is expected to be realized by the superposition of the radiation field on the phase decomposition array element in the far field region.

5. The method of claim 1, wherein the method comprises: in step S4, when the beam direction of the array antenna changes, the control voltage on the corresponding radiating element in the array antenna is refreshed by the antenna control system, so as to implement the switching of the beam direction and achieve the reproduction of the array antenna pattern.

Technical Field

The invention relates to the field of communication and algorithm, in particular to a liquid crystal array antenna beam forming and self-adaptive control method based on phase decomposition.

Background

The traditional phased-array antenna adopts a mode of adding an attenuator and a phase shifter to control the amplitude and the phase of a radiation field of each antenna unit. Firstly, each radiation unit forms a two-dimensional or three-dimensional array structure, then a feed weight complex vector corresponding to each antenna unit is determined according to the beam pointing requirement, and the feed weight of each array element is realized by connecting an attenuator and a phase shifter to each radiation unit, thereby realizing the digital beam forming and pointing scanning of the array antenna.

The metamaterial array antenna including the liquid crystal array antenna can realize digital beam forming and directional control of the array antenna without an attenuator and a phase shifter. This can reduce the manufacturing cost of the antenna to a great extent. Meanwhile, the metamaterial array antenna comprising the liquid crystal array antenna has a lower section, smaller volume and lighter weight due to no attenuator and phase shifter. Therefore, the method has great application prospect in the fields of satellite communication, Internet of things, Internet of vehicles and 5G millimeter wave communication.

Disclosure of Invention

In the liquid crystal array antenna, for a feeding weight repeated vector of an array element corresponding to a certain beam direction, each feeding weight repeated vector can be decomposed on two or more liquid crystal units with a certain phase difference through phase decomposition, the deflection state of liquid crystal in each radiation unit is subjected to amplitude through an external electric field, and phase control is realized through optical path difference between the phase decomposition units, so that the coding of the feeding weight repeated vector on the liquid crystal array is realized. And repeating the coding of the feeding weight repeated vector once in the liquid crystal array for each directed wave beam, thereby realizing the directional control of the liquid crystal array antenna.

Based on the above background, the present invention regulates and controls the deflection state of the liquid crystal in each radiation unit in the liquid crystal array antenna by the sum moment generated between the external electric field and the dipole moment of the polarized liquid crystal, thereby realizing the regulation and control of the electromagnetic field amplitude in each radiation unit, realizing the phase control of each liquid crystal unit by the optical path difference between the phase decomposition units, and providing the algorithm of digital beam forming and finger adaptive direction control of the liquid crystal array antenna on the basis of the regulation and control method.

The invention aims to provide a liquid crystal array antenna beam forming and self-adaptive control method based on phase decomposition, which comprises the following steps:

s1, giving a radiation pattern function of a desired array antenna;

s2, by aiming at the given partyApproximating the graph function to determine the feed weight vector of each array element；

S3, for eachPerforming phase decomposition on the array plane, and determining the distribution of phase decomposition array elements corresponding to a certain beam direction;

and S4, realizing the array distribution of the liquid crystal deflection state in the phase decomposition array element through the driving system of the antenna so as to realize the expected array antenna radiation pattern.

Optionally, in step S3The component sizes of the array element radiation fields Eij in the two corresponding phase decomposition units on the x axis and the y axis are realized by adjusting the deflection degree of the liquid crystal in the phase decomposition array elements.

Optionally, the adjusting of the degree of deflection of the liquid crystal includes applying an electric field and controlling the magnitude change thereof, so that liquid crystal molecules in the polarized liquid crystal material are deflected to different degrees.

Optionally, step S4 includes determining each of the phase-resolved array elements by applying a voltage drive signal to each of the phase-resolved array elements to effect an array distribution of liquid crystal deflection states in the phase-resolved array elementsThe corresponding magnitude values on the two decomposition units; and the radiation pattern of the array antenna is expected to be realized by the superposition of the radiation field on the phase decomposition array element in the far field region.

Optionally, in step S4, when the beam direction of the array antenna changes, the control system of the antenna refreshes the control voltage on the corresponding radiation element in the array antenna, so as to implement the switching of the beam direction, and achieve the reproduction of the array antenna pattern.

Compared with the prior art, the invention provides a liquid crystal array antenna beam forming and self-adaptive control method based on phase decomposition, which has the following beneficial effects:

the invention regulates and controls the deflection state of the liquid crystal in each radiation unit in the liquid crystal array antenna, thereby realizing the regulation and control of the electromagnetic field amplitude in each radiation unit, realizing the phase control of each liquid crystal unit through the optical path difference between the phase decomposition units, and forming a common method for beam synthesis and pointing control of the liquid crystal array antenna and other metamaterial array antennas.

Drawings

FIG. 1 is a schematic diagram of array unit distribution and orientation in the xy plane;

FIG. 2 is a schematic diagram of a beam forming process of an array antenna;

FIG. 3 is an exploded view of an array element radiation vector;

FIG. 4 is a schematic diagram of the synthesis of array element beams after phase decomposition;

FIG. 5 is a schematic diagram of the deflection of a polarized liquid crystal under an external field;

FIG. 6 is a schematic diagram of a rectangular grid rectangular boundary two-dimensional array distribution;

FIG. 7 is a schematic diagram of a rectangular grid circular boundary two-dimensional array distribution;

FIG. 8 is a schematic diagram of a rectangular grid hexagonal boundary two-dimensional array distribution;

FIG. 9 is a schematic diagram of a two-dimensional array distribution of triangular grid rectangular boundaries;

FIG. 10 is a schematic diagram of a triangular grid circular boundary two-dimensional array distribution;

FIG. 11 is a schematic diagram of a two-dimensional array distribution of triangular lattice hexagonal boundaries;

FIG. 12 is a schematic view of a circular array distribution;

FIG. 13 is a schematic diagram of a concentric ring array arrangement;

FIG. 14 is a schematic diagram of a two-dimensional conformal array layout on a curved surface;

FIG. 15 is a schematic diagram of a single-axis crystal with refractive index ellipsoids and their modulation of transmitted electromagnetic waves;

FIG. 16 is a schematic diagram of a liquid crystal array antenna beam forming and pointing control process;

fig. 17 is an equal-sidelobe array antenna pattern with 60 ° directivity realized by the phase decomposition method.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example (b): as shown in FIG. 1, assuming that the antenna is an array in the xy plane, the position vector of a certain array element is _ijThe director of the beam isThe angle between the beam director and the z-axis isThe projection of the director on the xy plane forms an angle with the x axisThus, the spatial phase factor of the array element radiation pattern can be expressed as

As shown in fig. 2, for an array antenna, the input signal of each array element is represented asFor the feed weight vector of each array elementIt is shown that, in far-field approximation, the radiation pattern function S of an array antenna can be expressed as:

wherein the content of the first and second substances,

thus, a feed weight vector for each array element is determinedAfter the complex values of (a), the beam forming and pointing of the array antenna can be theoretically determined. Because of the fact thatIs complex, so how to implement the feeding weight by the antenna element is the key of the problem. For each element in the liquid crystal array antenna, its radiation field E_ijThe decomposition is performed in the manner shown in fig. 3, where each axis x and y corresponds to an element in the liquid crystal array antenna, E_ijAngle to the 0 phase reference axisIs composed ofThe argument of (2) has a component Ex on the x-axis and a component Ey on the y-axis. Thus, one is providedThe values of (a) are resolved on two spaced elements of the liquid crystal array antenna, and the spacing of the two phase resolved elements depends on the direction of the synthesized beam and the angle between the x-axis and the y-axis.

In principle there may be anything between the x-axis and the y-axisBy angle, when the angle between the x-axis and the y-axis isThe x-axis may correspond to any one half-axis of the rectangular coordinate system, and the y-axis may correspond to a phase greater than the x-axisThe other half shaft of (a). Corresponding to the array elements of the liquid crystal array antenna, namely the x axis and the y axis respectively correspond to two quarter wavelengths with the distance of () The phase of (2) decomposes the array elements.

If the array antenna beam is required to be directed as shown in fig. 4The array element spacing is d, then with oneThe distance between two corresponding phase-resolved array elements isThe electromagnetic fields radiated by the two phase-resolved array elements are combined into oneThe radiated electromagnetic field of the corresponding array element. And the position of the array element is selected according toIf the included angle between the x-axis and the y-axis is taken asWhen is coming into contact withWhen the argument of (2) is in a first quadrant, the bits of the first phase-resolved array elementSet to 0 phase reference point, the position of another phase decomposition unit corresponding to the phase reference point is the closestTo (3). When in useWhen the argument of (b) is in the second quadrant, the x-axis in fig. 3 corresponds to the positive half-axis of the y-axis in the rectangular coordinate system, and the y-axis in fig. 3 corresponds to the negative half-axis of the x-axis in the rectangular coordinate system. The position of the first phase resolved array element is shifted by a distance dx relative to the 0 phase reference point which satisfies the following relationship:

the other phase decomposition unit corresponding to the first phase decomposition element is positioned closest to the first phase decomposition elementTo (3).When the argument of (a) is in the third and fourth image, the selection of the x-axis and y-axis and the selection of the position of the first phase-resolved array element are the same asThe same method is adopted for selecting the distance between the two corresponding phase decomposition array elements. After the position of the first pair of phase-resolved array elements is determined, the positions of the other pairs of phase-resolved array elements are determined by the array element spacing d.

Thus, with oneIn the corresponding two phase decomposition units, the phase relation between each other has been determined. The component size of the array element radiation field Eij on the x axis and the y axis is realized by adjusting the deflection degree of the liquid crystal in the phase decomposition array element.

As shown in fig. 5, the liquid crystal material used in the liquid crystal array antenna of the present invention can be polarized under the action of an electric field. Polarization dipole momentpAn included angle exists between the polarization dipole moment and the external electric field along the long axis direction of the liquid crystal molecules, so that a rotation moment exists on the liquid crystal molecules, and the liquid crystal molecules can deflect to different degrees when the size of the external electric field changes.

The invention provides an antenna array structure formed by combining radiation units formed by the method for regulating microwave and millimeter waves based on the liquid crystal and the radiation structure, which includes, but is not limited to, a rectangular grid rectangular boundary two-dimensional array distribution schematic diagram shown in fig. 6, a rectangular grid circular boundary two-dimensional array distribution schematic diagram shown in fig. 7, a rectangular grid hexagonal boundary two-dimensional array distribution schematic diagram shown in fig. 8, a triangular grid rectangular boundary two-dimensional array distribution schematic diagram shown in fig. 9, a triangular grid circular boundary two-dimensional array distribution schematic diagram shown in fig. 10, a triangular grid hexagonal boundary two-dimensional array distribution schematic diagram shown in fig. 11, a circular ring array distribution schematic diagram shown in fig. 12, a concentric ring array distribution schematic diagram shown in fig. 13, and a two-dimensional conformal array distribution schematic diagram shown in fig. 14 and located on a curved surface.

FIG. 15 shows a refractive index ellipsoid of the liquid crystal material of the present invention. The liquid crystal material has only one main optical axis. The plane perpendicular to the main optical axis is a circular plane, indicating that the refractive indices of the materials are equal in the direction perpendicular to the main optical axis (n _x =n _y ). The electromagnetic wave is transmitted along the main optical axis without any change. If the direction of propagation of the electromagnetic wavekAt an angle to the main optical axis of the liquid crystal molecules, while the vibration direction of the electric field is not within the iso-refractive index circle, e.g. along the line in fig. 15n _e And (4) direction. Then, relative to the movement in the direction of the main optical axis,n _e the refractive index in the direction increases and the speed of movement of the electromagnetic wave in that direction slows. Therefore, when the liquid crystal is driven by an applied voltage and deflected to different degrees, the propagation direction of the electromagnetic wave will be the same as that of the liquid crystalThere are different degrees of included angle between the principal optical axes of the crystals. So that the vibrating electric field corresponds to different refractive indices or dielectric constants. The movement speeds of the electromagnetic waves in the liquid crystal molecules in different deflection states are different, and therefore required amplitude modulation in a certain direction is achieved.

The invention provides a wave velocity and synthesis and control method of a liquid crystal array antenna based on the method, and the specific flow is shown in fig. 16. First, it is necessary to give the desired radiation pattern function of the array antenna in a certain direction. Secondly, determining the feed weight vector of each array element by approximating a given directional diagram function. After determining the feeding weight vector corresponding to each radiation element, the phase decomposition method is used to determine the feeding weight vector corresponding to each radiation elementPerforming phase decomposition on the array plane, determining the distribution of the phase decomposition array elements corresponding to a certain beam direction, thereby determining eachThe corresponding phase distribution. Finally, each phase decomposition array element is loaded with a voltage driving signal to realize the array distribution of the liquid crystal deflection state in the phase decomposition array element, thereby determining each phase decomposition array elementThe corresponding magnitude is a value on both decomposition units. And finally, realizing the expected array antenna radiation pattern by superposing the radiation field on the phase decomposition array element in the far field region. When the beam direction of the array antenna is changed, the control voltage on the corresponding radiation unit in the array antenna is refreshed through the antenna control system, so that the beam direction switching is realized, and the reproduction of the array antenna directional pattern is achieved. FIG. 17 is a diagram of an example of an equal sidelobe array with 60 ° directivity by phase decompositionColumn antenna patterns.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.