阅读说明：本技术 一种柱面螺旋式共形液晶移相器 (Cylindrical surface spiral type conformal liquid crystal phase shifter ) 是由 蒋迪 白天明 朱凯 张唯燚 于 2021-07-07 设计创作，主要内容包括：本发明涉及天线技术领域,公开了一种柱面螺旋式共形液晶移相器,通过柱面螺旋式共形液晶移相器的内部结构从上至下依次设置有下层基板、接地金属层、液晶层、传输线和上层基板。本发明设计的柱面螺旋式共形液晶移相器可与柱面载体共形,进一步节省空间,并在12GHz-20GHz的宽频带内实现覆盖360°相位连续可调功能,有效解决传统移相方式对于相位控制的精度不足及无法与载体共形的问题,满足共形相控阵天线的发展需求。(The invention relates to the technical field of antennas and discloses a cylindrical surface spiral type conformal liquid crystal phase shifter. The cylindrical spiral conformal liquid crystal phase shifter designed by the invention can be conformal to a cylindrical carrier, further saves space, realizes the function of continuously adjusting the phase covering 360 degrees in a wide frequency band of 12GHz-20GHz, effectively solves the problems that the traditional phase shifting mode has insufficient precision for phase control and cannot be conformal to the carrier, and meets the development requirements of conformal phased array antennas.)

1. A cylindrical spiral conformal liquid crystal phase shifter is characterized in that,

the cylindrical surface spiral type conformal liquid crystal phase shifter is arranged in a cylindrical surface spiral structure, a lower substrate, a grounding metal layer, a liquid crystal layer, a transmission line and an upper substrate are sequentially arranged in the cylindrical surface spiral type conformal liquid crystal phase shifter from top to bottom, the upper substrate is in contact with a liquid crystal material on the liquid crystal layer, and a circuit of the transmission line is etched on the lower surface of the upper substrate.

2. The cylindrical spiral conformal liquid crystal phase shifter of claim 1,

the tunability of the liquid crystal layer is manifested in that the resonance frequency changes with the change of the dielectric constant of the liquid crystal material.

3. The cylindrical spiral conformal liquid crystal phase shifter of claim 1,

the tuning capability of the liquid crystal layer is related to the material properties and the variation of its dielectric constant.

4. The cylindrical spiral conformal liquid crystal phase shifter of claim 3,

and simulating the response of the liquid crystal layer to an applied electric field by using a parallel plate capacitor, and calculating the length of a corresponding phase shifter according to the required phase shift quantity.

5. The cylindrical spiral conformal liquid crystal phase shifter of claim 1,

the cylindrical spiral conformal liquid crystal phase shifter changes the capacitance value by adjusting the effective dielectric constant of a medium in the transmission process of electromagnetic waves, and further changes the phase shift constant of the electromagnetic waves in the transmission process.

6. The cylindrical spiral conformal liquid crystal phase shifter of claim 1,

the maximum phase shift amount of the cylindrical spiral conformal liquid crystal phase shifter is determined by the length of the phase shifter and the variation of the dielectric constant.

Technical Field

The invention relates to the technical field of antennas, in particular to a cylindrical spiral conformal liquid crystal phase shifter.

Background

The requirements for phased array antennas are becoming higher and higher in the development of modern electronic information technology, and as an improved phased array antenna, conformal phased array antennas suitable for aircraft, ships, wearable equipment and the like which need to be attached to the surface of a carrier are widely researched. The conformal phased array antenna changes a phased array of a plane structure into a curved surface structure, so that the conformal phased array antenna can be conformal with the surface of a carrier, is designed in a thin mode, and reduces the quality of the conformal phased array antenna. Compared with the traditional linear array and planar array, the conformal array has unique and superior performance, and the conformal antenna enlarges the beam scanning range; the degree of freedom of antenna installation is improved; the radar cross-sectional area is reduced, the radar cross-sectional area can be installed at any position of an aircraft and the like, the aerodynamic performance of a carrier aircraft is not changed, multiple targets can be processed simultaneously through comprehensive control of a plurality of antennas, and large-scale searching, blind area elimination and the like can be carried out instantly.

As a key device for realizing beam integration and beam scanning of the phased array antenna, the phase shifter can realize compensation of time difference of arrival of signals at radiating elements, and signals received by all the radiating elements are subjected to phase compensation through the corresponding phase shifters, so that all the signals can be added in phase, and beams are directed to a preset angle. By controlling and changing the phase compensation quantity of each phase shifter, the antenna beam scanning function can be realized, and the application value of the antenna is further expanded.

Based on the research of the traditional planar phased array, certain achievements are obtained in the aspects of the radiation unit design, the wave beam control algorithm and the like of the conformal phased array antenna, but the phase shift mode of the traditional planar structure is still adopted in consideration of the design of the phase shift structure. However, the conventional planar phase shifting method is contrary to the conformal design concept, and it is difficult to further exert the value of the conformal phased array antenna, so that a novel phase shifter which can be conformal to the surface of the carrier needs to be designed by using a novel material, and the optimal design of the conventional conformal phased array antenna is realized.

Disclosure of Invention

The invention aims to provide a cylindrical spiral conformal liquid crystal phase shifter, and aims to solve the technical problems that the traditional phase shifting mode is insufficient in phase control precision, cannot conform to a carrier, and cannot meet the development requirements of conformal phased-array antennas.

In order to achieve the above purpose, the cylindrical surface spiral type conformal liquid crystal phase shifter is arranged in a cylindrical surface spiral structure, an internal structure of the cylindrical surface spiral type conformal liquid crystal phase shifter is sequentially provided with a lower substrate, a grounding metal layer, a liquid crystal layer, a transmission line and an upper substrate from top to bottom, the upper substrate is in contact with a liquid crystal material on the liquid crystal layer, and a circuit of the transmission line is etched on the lower surface of the upper substrate.

Wherein the tunability of the liquid crystal layer is manifested in that the resonant frequency changes with the change of the dielectric constant of the liquid crystal material.

Wherein, the tuning capability of the liquid crystal layer is related to the material characteristics and the variation range of the dielectric constant thereof.

And simulating the response of the liquid crystal layer to an applied electric field by using a parallel plate capacitor, and calculating the length of a corresponding phase shifter according to the required phase shift quantity.

The cylindrical spiral conformal liquid crystal phase shifter changes the capacitance value by adjusting the effective dielectric constant of a medium in the transmission process of electromagnetic waves, and further changes the phase shift constant of the electromagnetic waves in the transmission process.

The maximum phase shift amount of the cylindrical spiral conformal liquid crystal phase shifter is determined by the length of the phase shifter and the variation of the dielectric constant.

According to the cylindrical surface spiral type conformal liquid crystal phase shifter, the lower substrate, the grounding metal layer, the liquid crystal layer, the transmission line and the upper substrate are sequentially arranged from top to bottom through the internal structure of the cylindrical surface spiral type conformal liquid crystal phase shifter, wherein the transmission line circuit is etched on the lower surface of the upper substrate which is in contact with a liquid crystal material, energy is fed in from the lower end, and energy is fed out from the upper end. The liquid crystal layer is arranged between the upper substrate and the lower substrate, and the control of the dielectric constant of the liquid crystal is realized through the voltage applied by the grounding metal layer, so that the phase shift function is realized. The cylindrical spiral conformal liquid crystal phase shifter designed by the invention can be conformal to a cylindrical carrier, further saves space, realizes a continuous adjustable function of covering 360-degree phase within a wide frequency band of 12GHz-20GHz, effectively solves the problems that the traditional phase shifting mode has insufficient precision for phase control and cannot be conformal to the carrier, and meets the development requirements of conformal phased array antennas.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a side view of a cylindrical spiral conformal liquid crystal phase shifter of the present invention.

FIG. 2 is a top view of a cylindrical spiral conformal liquid crystal phase shifter of the present invention.

FIG. 3 is a liquid crystal molecule arrangement in a different aspect of the present invention.

FIG. 4 is a diagram of S-parameters of a phase shifter simulated by the present invention.

FIG. 5 is a schematic diagram of the phase shifting range of the phase shifter of the present invention.

FIG. 6 is a schematic diagram of a 1X4 cylindrical helical liquid crystal phase shifter according to the present invention.

FIG. 7 is a schematic diagram of the optimized 1 × 4 phaser array S parameters of the present invention.

Fig. 8 is a schematic diagram of the phase shifter array of the present invention with phase shifters (a), (b), (c), and (d).

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, and are used merely for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention. Further, in the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

Referring to fig. 1 to 8, the present invention provides a cylindrical spiral conformal liquid crystal phase shifter, wherein the cylindrical spiral conformal liquid crystal phase shifter is arranged in a cylindrical spiral structure, an internal structure of the cylindrical spiral conformal liquid crystal phase shifter is sequentially provided with a lower substrate, a ground metal layer, a liquid crystal layer, a transmission line and an upper substrate from top to bottom, the upper substrate is in contact with a liquid crystal material on the liquid crystal layer, and a circuit of the transmission line is etched on a lower surface of the upper substrate.

In this embodiment, a lower substrate, a ground metal layer, a liquid crystal layer, a transmission line, and an upper substrate are sequentially disposed from top to bottom through an internal structure of the cylindrical spiral conformal liquid crystal phase shifter, wherein the transmission line is etched on a lower surface of the upper substrate in contact with a liquid crystal material, energy is fed in from a lower end, and energy is fed out from an upper end. The liquid crystal layer is arranged between the upper substrate and the lower substrate, and the control of the dielectric constant of the liquid crystal is realized through the voltage applied by the grounding metal layer, so that the phase shift function is realized. The cylindrical spiral conformal liquid crystal phase shifter designed by the invention can be conformal to a cylindrical carrier, further saves space, realizes a continuous adjustable function of covering 360-degree phase within a wide frequency band of 12GHz-20GHz, effectively solves the problems that the traditional phase shifting mode has insufficient precision for phase control and cannot be conformal to the carrier, and meets the development requirements of conformal phased array antennas.

Further, the tunability of the liquid crystal layer is manifested in that the resonance frequency changes with the change of the dielectric constant of the liquid crystal material.

The tuning capability of the liquid crystal layer is related to the material properties and the variation of its dielectric constant.

And simulating the response of the liquid crystal layer to an applied electric field by using a parallel plate capacitor, and calculating the length of a corresponding phase shifter according to the required phase shift quantity.

The cylindrical spiral conformal liquid crystal phase shifter changes the capacitance value by adjusting the effective dielectric constant of a medium in the transmission process of electromagnetic waves, and further changes the phase shift constant of the electromagnetic waves in the transmission process.

The maximum phase shift amount of the cylindrical spiral conformal liquid crystal phase shifter is determined by the length of the phase shifter and the variation of the dielectric constant.

The liquid crystal layer tuning capability is determined by a tuning force τ_LCAnd material efficiency η_LCExpressed as follows:

the applied electric or magnetic field deflects the liquid crystal molecules in the axial direction, thereby changing the dielectric constant of the liquid crystal material. In general, when the applied electric field coincides with the long axis of the liquid crystal molecules, the measured dielectric constant of the liquid crystal is defined as ε_//(ii) a When the applied electric field is perpendicular to the long axis of the liquid crystal molecules, the measured dielectric constant is defined as ∈_⊥And the difference Δ ∈ between the two is defined as dielectric anisotropy. tan δ is the loss tangent of the material, and max (tan δ) is the maximum loss tangent of the material.

A uniform electric field exists on the right part of the two plates of the parallel plate capacitor, so that the liquid crystal pointing directions in the parallel plates are kept consistent under an offset state;

in a facing parallel plate capacitor, the capacitance can be calculated by the following equation:

wherein C is a capacitance value, epsilon is a dielectric constant of a medium between the plates, S is a facing area of the two plates, d is a distance between the two plates, and k is an electrostatic force constant.

The core of the work of the liquid crystal phase shifter is that the effective dielectric constant of a medium in the transmission process of electromagnetic waves is adjusted to change a capacitance value, so that the phase shift constant of the electromagnetic waves in the transmission process is changed:

wherein beta is a phase shift constant, omega is an angular frequency, L is a transmission line unit inductance, C is two transmission line unit capacitance values, mu is a transmission line material magnetic conductivity, and epsilon is a transmission line material dielectric constant

β_||And beta_⊥The phase shift constants of the liquid crystal in the two states of bias and alignment, respectively, the differential phase shift produced when the effective dielectric constant of the liquid crystal is changed is:

β_||and beta_⊥Phase shift constants of the liquid crystal in a bias state and an alignment state are respectively obtained; when the applied electric field is consistent with the long axis of the liquid crystal molecules, the measured dielectric constant of the liquid crystal is defined as epsilon_//(ii) a When the applied electric field is perpendicular to the long axis of the liquid crystal molecules, the measured dielectric constant is defined as ∈_⊥(ii) a Wherein l corresponds to the physical length of the phase shifter, c₀Is the speed at which light propagates in a vacuum.

In this embodiment, the working principle of the cylindrical spiral conformal liquid crystal phase shifter is as follows:

the liquid crystal material of the liquid crystal layer has dielectric anisotropy, and the axial direction of liquid crystal molecules in the liquid crystal material can be changed by applying an electric field or a magnetic field to the outside, so that the dielectric constant of the material is changed, and the liquid crystal layer has tunability. In particular, the tunability of the liquid crystal material is shown in that when the liquid crystal material is used as a dielectric substrate, the resonant frequency changes along with the change of the dielectric constant of the liquid crystal material, which is also the basis of the liquid crystal material as the tunable material.

Tuning for liquid crystal materialsThe description of the capability can generally be by tuning the force τ_LCAnd material efficiency η_LCExpressed as follows:

the response of a liquid crystal layer in the liquid crystal phase shifter to an applied electric field can be simulated by using an ideal parallel plate capacitor, and the corresponding phase shifter length can be calculated according to the required phase shift quantity.

Under ideal conditions, a uniform electric field exists at the positive part of the two plates of the parallel plate capacitor, so that the liquid crystal pointing directions in the parallel plates can be kept consistent under a bias state. In a facing parallel plate capacitor, the capacitance can be calculated by the following equation:

the core of the work of the liquid crystal phase shifter is that the effective dielectric constant of a medium in the transmission process of electromagnetic waves is adjusted to change a capacitance value, and then the phase shift constant of the electromagnetic waves in the transmission process is changed:

β_||and beta_⊥The phase shift constants of the liquid crystal in the two states of bias and alignment, respectively, the differential phase shift produced when the effective dielectric constant of the liquid crystal is changed is:

wherein l corresponds to the physical length of the phase shifter, c₀Is that light propagates in vacuumThe speed of (2). The maximum phase shift amount of the phase shifter is determined by both the length of the phase shifter and the amount of change in the dielectric constant.

The cylindrical spiral structure parameter equation is as follows:

x＝r cos(θ) (6)

y＝r sin(θ) (7)

z＝bθ (8)

wherein x, y and z are graphic coordinates, theta is an angle variable and ranges from 0 pi to 2 pi.

Where r is the radius of the conformal cylinder and b is the rise per turn of the helix. The internal structure can be roughly divided into: the liquid crystal display device comprises a lower substrate, a grounding metal layer, a liquid crystal layer, a transmission line and an upper substrate. The transmission line circuit is etched on the lower surface of the upper substrate which is in contact with the liquid crystal material, energy is fed in from the lower end, and energy is fed out from the upper end. The liquid crystal layer is arranged between the upper substrate and the lower substrate plate, and the dielectric constant of the liquid crystal is controlled by applying voltage to the grounding metal layer, so that the phase shift function is realized.

The S parameter of the phase shifter obtained through simulation is shown in FIG. 4:

it can be seen that the phase shifter S is arranged in the range of 12GHz-18GHz₁₁Are all lower than-10 dB, S₂₁Are all higher than-5 dB, and the curve is more stable.

The phase shift amount changes as shown in FIG. 5 below:

it can be seen that in the range of the dielectric constant of the liquid crystal layer varying from 2.5 to 3.3, the amount of phase shift gradually increases with frequency, and the phase shift range exceeds 360 ° at 12 GHz. Under the designed working frequency of 15GHz, the phase shifting range can reach 794 degrees, and the phase shifting requirement is far beyond 360 degrees.

For the design of a phase shifter array, the phase shifter is,

based on the designed phase shifter structure, a 1 × 4 phase shifter array was designed to verify its possibility of application to a conformal phased array antenna. The simulation model diagram is shown in FIG. 6:

the results of the simulation with the phase shifter spacing of 14mm combined with other optimization parameters are shown in fig. 7.

At this time, the phase shift amount of each phase shifter is shown in fig. 8, and it can be seen that, at 15GHz, the phase shift amount is greater than 360 ° in the variation range of the liquid crystal dielectric constant from 2.5 to 3.3, and the phase shifter requirement is satisfied.

To sum up, a novel cylindrical spiral phase shifter based on a liquid crystal material is designed for a conformal phased array antenna, and the designed working frequency is 15 GHz. Simulation shows that the phase shifter can realize phase shift amount far higher than 360 deg. in the variation range of dielectric constant 2.5-3.3. And 1x4 phase shifter array simulation is carried out based on the phase shifter, S11< -10dB and S21 < -6dB in the range of 14GHz-16GHz can be realized after optimization, the phase shift quantity of each array element is larger than 360 degrees, and the phase shifter can be further applied to conformal phased array antennas.

The phase shifter has the defects that the phase shifting control precision is not high, and continuous adjustability is difficult to realize, so that the performance of a phased array antenna array is influenced. Secondly, due to the limitation of materials, the conformal design of the conformal phased array with a curved surface is difficult to realize, and the design and optimization of the conformal phased array are influenced.

Aiming at the requirements of phase shift control and conformal design of a conformal phased array, for a common cylindrical conformal scene, the cylindrical spiral conformal liquid crystal phase shifter provided by the invention can realize continuous and adjustable phase, and meanwhile, because the material has certain fluidity, the curved surface conformal design is easy to realize, and the scheme and thought of conformal phased array antenna design can be expanded.

In conclusion, the novel cylindrical spiral conformal liquid crystal phase shifter based on the liquid crystal material accords with the development trend of realizing excellent performance by new materials, new technologies and new processes, and the design and application range of the conformal phased-array antenna is enlarged.

Therefore, compared with the traditional phase shifter structure, the cylindrical spiral conformal liquid crystal phase shifter provided by the invention has the advantages of continuously adjustable phase, conformal with the cylindrical surface, space occupation saving and the like, and further expands the design scheme and application mode of the conformal phased array antenna.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.