CN111244620A - Beam-scanning antenna array based on liquid crystal high-resistance surface - Google Patents

Abstract

The invention provides a beam scanning antenna array based on a liquid crystal high-resistance surface, comprising an antenna array (1), a high-resistance surface (2), a liquid crystal (3), a metal ground (4) and a dielectric plate (5); the The antenna array (1) can radiate electromagnetic waves to the outside; the high resistance surface (2) can control the coupling strength between the antenna elements of the antenna array (1); the liquid crystal (3) can realize the adjustment of the equivalent dielectric constant; The metal ground (4) can carry the antenna array (1), the high-resistance surface (2) and the liquid crystal (3) and provide a ground signal; the dielectric plate (5) can be used as a substrate to carry the antenna array (1), the high-resistance surface (2) and the liquid crystal (3); Surface (2), liquid crystal (3) and metal ground (4). The invention has the characteristics of continuously adjustable pattern, simple design, low cost and low DC power consumption, and is suitable for access point antennas.

Description

Beam-scanning antenna array based on liquid crystal high-resistance surface

technical field

The present invention relates to the field of antenna technology, in particular, to a beam scanning antenna array based on a liquid crystal high-resistance surface.

Background technique

Recent developments in next generation communication systems have increased the need for antenna systems capable of high data transfer rates. Therefore, reconfigurable smart antenna systems are more attractive. Reconfigurable antennas can be divided into frequency reconfigurable antennas, pattern reconfigurable antennas, polarization reconfigurable antennas and multifunctional reconfigurable antennas according to their functions. The beam scanning antenna array is a kind of pattern reconfigurable antenna, and its maximum radiation direction can point to any angle within a certain range. In order to achieve the tunability of the beam direction, phased array is a common way. Phased arrays require adjustable feed networks and phase shifters. However, the design of tunable feed networks and phase shifters is complex, costly and bulky.

In microstrip circuits, PIN diodes or varactors are often used to achieve reconfigurability. But as the frequency increases, the PIN diodes and varactors have parasitic effects. Therefore they are not suitable for high frequencies.

Nematic liquid crystals, as a continuously tunable anisotropic dielectric, play an important role in tunable materials. The dielectric constant of liquid crystal is changed by applying an electrostatic field or a magnetic field. Liquid crystals are widely used in reflectarrays and tunable leaky-wave antennas. However, the large dielectric loss angle of the liquid crystal will bring about a large dielectric loss and reduce the gain and radiation efficiency of the antenna.

A high resistance surface is a periodic structure. Reconfigurability is achieved by adding semiconductor devices and control circuits between cells. However, such a reconfigurable high-resistance surface often requires a large number of semiconductor devices, so the structure is complex, and there will be large DC power consumption.

The patent document with publication number CN106932933A discloses a liquid crystal antenna and a manufacturing method thereof. The liquid crystal antenna includes: an antenna array and at least one inertial navigation unit; wherein, the antenna array is used to change the phase of the electromagnetic wave signal fed into the liquid crystal antenna, forming a The beam corresponding to the target direction; the inertial navigation unit is used to determine the motion parameters of the antenna in the navigation coordinate system; there is a seed layer between the inertial navigation unit and the substrate. In this way, the present invention integrates the inertial navigation unit and the antenna array by adding a seed layer and adopts a semiconductor process, thereby improving the integration of the antenna system, which is conducive to realizing the miniaturization and multi-functional development of the antenna system; at the same time, the antenna array can Accurate control of the antenna beam is achieved, and accurate positioning of the antenna movement can be achieved through the inertial navigation unit. However, the large dielectric loss angle of the liquid crystal will bring about a large dielectric loss and reduce the gain and radiation efficiency of the antenna.

SUMMARY OF THE INVENTION

In view of the defects in the prior art, the purpose of the present invention is to provide a beam scanning antenna array based on a liquid crystal high resistance surface.

A beam scanning antenna array based on a liquid crystal high-resistance surface provided according to the present invention includes an antenna array, a high-resistance surface, a liquid crystal, a metal ground and a dielectric plate;

The antenna array can radiate electromagnetic waves to the outside;

The high-resistance surface can control the coupling strength between the antenna elements of the antenna array;

The liquid crystal can realize the adjustment of the equivalent dielectric constant;

The metal ground can carry the antenna array, the high-resistance surface and the liquid crystal and provide the grounding signal;

The dielectric plate can be used as a substrate to carry an antenna array, a high-resistance surface, a liquid crystal, and a metal ground.

Preferably, the antenna array includes a main radiating element and two parasitic elements, and the two parasitic elements are symmetrically distributed on both sides of the main radiating element.

Preferably, the antenna array adopts an electronically controlled parasitic antenna array, the radio frequency signal is only fed to the main radiating unit, and there is no radio frequency feeding circuit on the parasitic unit.

Preferably, the antenna elements of the antenna array are rectangular, square or circular microstrip antennas; the antenna elements are arranged along the H plane.

Preferably, the antenna units of the antenna array are patch antennas.

Preferably, a feeding device is also included, the feeding device adopts probe feeding, microstrip line feeding or slot coupling feeding, and the feeding device is connected to the main radiating unit.

Preferably, the high-resistance surface is a periodic structure formed by coplanar electromagnetic bandgap units, and the coplanar electromagnetic bandgap units are rectangular, mushroom-shaped or cross-shaped.

Preferably, the equivalent dielectric constant of the liquid crystal changes with the change of the applied electric field or magnetic field.

Preferably, the medium plate includes a first medium plate, a second medium plate, and a third medium plate, and the first medium plate, the second medium plate, and the third medium plate are arranged and connected in sequence from top to bottom, and the first medium plate An antenna array is set on the upper surface of the board, two liquid crystal cells are set on the second dielectric board, the liquid crystal material is set in the liquid crystal cell, the high resistance surface is set between the lower surface of the first dielectric board and the liquid crystal, and the metal ground is set on the second dielectric board. between the lower surface of the medium plate and the upper surface of the third medium plate.

Preferably, the two liquid crystal cells are respectively arranged directly below the two parasitic units of the antenna array.

Compared with the prior art, the present invention has the following beneficial effects:

1. Compared with the traditional phased array antenna, the present invention adopts an electronically controlled parasitic antenna array, which does not require complicated feeding networks and phase shifters, which greatly simplifies the design.

2. Compared with the reconfigurable antenna using PIN diodes and varactor diodes, the present invention realizes that the equivalent dielectric constant can be adjusted through the liquid crystal. As the frequency increases, no parasitic effect is generated, and it is suitable for high frequencies.

3. Compared with the traditional liquid crystal antenna, the present invention places the liquid crystal under the parasitic unit, and there is no liquid crystal under the main radiation unit, so the dielectric loss is reduced, and the antenna gain and radiation efficiency are improved.

4. Compared with the traditional reconfigurable high-resistance surface, the present invention does not need to load devices between cells, and has a simple structure and no DC power consumption.

5. The present invention has the characteristics of continuously adjustable pattern, simple design, low cost and low DC power consumption, and is suitable for access point antennas.

Description of drawings

Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic structural diagram of the present invention.

FIG. 2 is a physical schematic diagram of an electrically controlled parasitic antenna array of the present invention.

FIG. 3 is a physical schematic diagram of the high resistance surface of the present invention.

FIG. 4 is a physical schematic diagram of the liquid crystal cell of the present invention.

FIG. 5 is the reflection coefficient in the initial state of the present invention.

FIG. 6 shows the reflection coefficient of the liquid crystal under the left parasitic unit changed to the maximum deflection state according to the present invention.

FIG. 7 shows the reflection coefficient of the liquid crystal under the right parasitic cell being changed to the maximum deflection state according to the present invention.

FIG. 8 is an H-plane orientation diagram in the initial state of the present invention.

FIG. 9 is an H-plane orientation diagram of the present invention changing the liquid crystal below the left parasitic cell to the maximum deflection state.

FIG. 10 is an H-plane orientation diagram of the present invention changing the liquid crystal below the right parasitic unit to the maximum deflection state.

The figure shows:

Antenna array 1 Liquid crystal 3 Dielectric plate 5

High resistance surface 2 Metal ground 4 Feeder 6

Detailed ways

The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the inventive concept. These all belong to the protection scope of the present invention.

In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", The orientation or positional relationship indicated by "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying the indicated device. Or elements must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as a limitation of the present application.

The present invention provides a beam scanning antenna array based on a liquid crystal high-resistance surface, including an antenna array 1 , a high-resistance surface 2 , a liquid crystal 3 , a metal ground 4 , a dielectric plate 5 and a feeding device 6 . The antenna array 1 is located on the upper surface of the first dielectric plate. The antenna array 1 is composed of a main radiating element and two parasitic elements. The antenna elements are arranged along the H plane, and the parasitic elements are symmetrically distributed on both sides of the main radiating element of the antenna. The RF signal is only fed to the main radiating unit, and there is no RF feeding circuit on the parasitic unit. The feeding method is the probe feeding, and the antenna unit is the patch antenna. The high resistance surface 2 is located on the lower surface of the first dielectric plate. The high resistance surface 2 is a periodic structure composed of coplanar electromagnetic bandgap elements. Two high resistance surfaces 2 are distributed under the two parasitic elements. The second dielectric plate has two liquid crystal cells, and the liquid crystal cells are located just below the high resistance surface 2 . The metal ground is located on the upper surface of the third dielectric plate. The high resistance surface 2, the liquid crystal 3 and the metal ground 4 constitute a new type of liquid crystal reconfigurable high resistance surface. In the present invention, the DC bias voltage is loaded between the high-resistance surface 2 and the metal ground 4 to change the equivalent dielectric constant of the liquid crystal 3, thereby controlling the coupling strength between the antenna array units and realizing the continuous adjustment of the antenna beam. The invention has the advantages of adjustable pattern, low cost, no power consumption and the like, and can be used for access point antennas.

A beam scanning antenna array based on a liquid crystal high-resistance surface provided according to the present invention, as shown in FIG. 1-10, includes an antenna array 1, a high-resistance surface 2, a liquid crystal 3, a metal ground 4 and a dielectric plate 5; the antenna The array 1 can radiate electromagnetic waves to the outside world; the high resistance surface 2 can control the coupling strength between the antenna elements of the antenna array 1; the liquid crystal 3 can realize the adjustment of the equivalent dielectric constant; the metal ground 4 can carry the antenna array 1. The high-resistance surface 2 and the liquid crystal 3 provide a ground signal; the dielectric plate 5 can be used as a substrate to carry the antenna array 1 , the high-resistance surface 2 , the liquid crystal 3 and the metal ground 4 .

As shown in FIG. 2 , the antenna array 1 includes a main radiating element and two parasitic elements, and the two parasitic elements are symmetrically distributed on both sides of the main radiating element. The antenna array 1 adopts an electronically controlled parasitic antenna array, and the radio frequency signal is only fed to the main radiating unit, and there is no radio frequency feeding circuit on the parasitic unit. The antenna elements of the antenna array 1 are rectangular, square or circular microstrip antennas; the antenna elements are arranged along the H plane. The antenna unit of the antenna array 1 is a patch antenna, and the antenna unit includes a main radiation unit and a parasitic unit. It also includes a feeding device 6, the feeding device 6 adopts probe feeding, microstrip line feeding or slot coupling feeding, and the feeding device 6 is connected to the main radiating unit. The feeding device 6 is only connected to the main radiating element, and feeds the main radiating element, but does not feed the parasitic element.

As shown in FIG. 3 , the high-resistance surface 2 is a periodic structure formed by coplanar electromagnetic bandgap units, and the coplanar electromagnetic bandgap units are rectangular, mushroom-shaped or cross-shaped. The equivalent permittivity of the liquid crystal 3 changes with the change of the applied electric field or magnetic field, that is, the liquid crystal 3 is a tunable material that can be deflected with the applied electric field or magnetic field, and its equivalent permittivity can vary with the strength of the applied field. change to change.

As shown in FIGS. 1-4 , the medium plate 5 includes a first medium plate, a second medium plate, and a third medium plate, and the first medium plate, the second medium plate, and the third medium plate are in order from top to bottom Arrangement and connection, the antenna array 1 is arranged on the upper surface of the first medium plate, two liquid crystal tanks are arranged on the second medium plate, the liquid crystal 3 material is arranged in the liquid crystal tank, and the high resistance surface 2 is arranged under the first medium plate. 3, a metal ground 4 is arranged between the lower surface of the second dielectric board and the upper surface of the third dielectric board. The two liquid crystal cells are respectively arranged directly below the two parasitic units of the antenna array 1 .

Preferably, a beam scanning antenna array based on a liquid crystal high resistance surface, as shown in FIG. 1 , includes: an antenna array 1 , a high resistance surface 2 , a liquid crystal 3 , a metal ground 4 and a dielectric plate 5 . The antenna array 1 shown is an electrically controlled parasitic antenna array, which is composed of three microstrip patch antenna units, arranged along the H plane, the main radiating unit is in the middle, and the two parasitic units are located on both sides. The coaxial feeding method is used to feed the RF signal to the main radiating element, and there is no RF signal on the parasitic element. The high-resistance surface 2 is a periodic structure consisting of 3 × 3 coplanar electromagnetic bandgap elements. The coplanar electromagnetic bandgap unit adopts a Jerusalem cross slot structure. Liquid crystal 3 is a continuously tunable material, the liquid crystal molecules can be deflected with the applied electric field or magnetic field, and its equivalent dielectric constant can be changed with the change of the intensity of the applied field. The two liquid crystals 3 are respectively disposed directly below the two parasitic units. The high resistance surface 2, the liquid crystal 3 and the metal ground 4 form a new type of liquid crystal adjustable high resistance surface.

In the initial state, the liquid crystals 3 on both sides are not deflected, the coupling between the main radiation unit and the parasitic units on both sides is weak, and the main beam points to zero degrees. When a bias voltage is applied to the high-resistance surface under the parasitic unit on the left, the liquid crystal molecules are deflected, the equivalent dielectric constant becomes larger, the coupling between the parasitic unit on the left and the main unit is enhanced, and the main beam is deflected to the left, realizing negative angle scanning . Similarly, when a bias voltage is applied to the high-resistance surface under the parasitic unit on the right, the coupling between the parasitic unit on the right and the main unit is enhanced to achieve positive angle scanning.

Preferred embodiment:

A beam scanning antenna array based on a liquid crystal high-resistance surface, the center frequency of this antenna array is 28GHz, and can be used for access point antennas.

As shown in FIG. 1 , the beam scanning antenna array on the liquid crystal high-resistance surface is composed of an antenna array 1, a high-resistance surface 2, a liquid crystal 3, a metal ground 4 and a dielectric plate 5. The antenna array 1 adopts an electrically controlled parasitic antenna array.

As shown in Figure 2, the main radiating element of the electronically controlled parasitic antenna array is a 3mm×3mm square microstrip patch antenna, and the two parasitic elements are both 2.6mm×2.6mm square microstrip patch antennas. The three antenna elements are arranged along the H plane, and the distance between the parasitic element and the main radiating element is 4.2mm. The dielectric plate 5 is a Rogers5880 rectangular dielectric with a dielectric constant of 2.2 and a loss tangent of 0.0009, and the size is 24mm×15mm×254um.

As shown in Fig. 3, the high-resistance surface 2 is a periodic structure composed of 3 × 3 coplanar electromagnetic bandgap elements. The coplanar electromagnetic bandgap unit adopts a Jerusalem cross slot structure, each unit has a length of 2.4mm and a width of 1.6mm, wherein the width of the Jerusalem cross slot is 0.15mm, and the length of the branch is 1.4mm. The gap is 0.15mm from the edge of each cell. The distance between the edges of the two high resistance surfaces 2 is 4mm.

As shown in FIG. 4 , the dimensions of the two liquid crystal cells are both 8mm×6mm×254um. The distance between the edges of the two liquid crystal cells is 3.7 mm.

In the initial state, the bias voltage applied on both sides is 0V, the liquid crystals on both sides are not deflected, the coupling between the main unit and the parasitic units on both sides is weak, and the main beam points to zero degrees. The reflection coefficient at this time is shown in Figure 5. , the direction diagram of the H surface is shown in Fig. 8. When a bias voltage is applied to the high-resistance surface under the parasitic unit on the left, the liquid crystal molecules are deflected, the equivalent dielectric constant becomes larger, the coupling between the parasitic unit on the left and the main unit is enhanced, and the main beam is deflected to the left, realizing negative angle scanning , the reflection coefficient at this time is shown in Figure 6, and the direction diagram of the H plane is shown in Figure 9. In the same way, when a bias voltage is applied to the high-resistance surface below the parasitic unit on the right, the coupling between the parasitic unit on the right and the main unit is enhanced to achieve positive angle scanning. The reflection coefficient at this time is shown in Figure 7. The orientation diagram is shown in Figure 10.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essential content of the present invention. The embodiments of the present application and features in the embodiments may be combined with each other arbitrarily, provided that there is no conflict.

Claims (10)

1. A wave beam scanning antenna array based on a liquid crystal high-resistance surface is characterized by comprising an antenna array (1), a high-resistance surface (2), a liquid crystal (3), a metal ground (4) and a dielectric plate (5);

the antenna array (1) can radiate electromagnetic waves to the outside;

the high-resistance surface (2) can control the coupling strength among the antenna units of the antenna array (1);

the liquid crystal (3) can realize the adjustability of equivalent dielectric constant;

the metal ground (4) can bear the antenna array (1), the high-resistance surface (2) and the liquid crystal (3) and provides a grounding signal;

the dielectric plate (5) is used as a substrate and can bear the antenna array (1), the high-resistance surface (2), the liquid crystal (3) and the metal ground (4).

2. The beam scanning antenna array based on liquid crystal high impedance surface as claimed in claim 1, characterized in that the antenna array (1) comprises a main radiating element and two parasitic elements, and the two parasitic elements are symmetrically distributed at two sides of the main radiating element.

3. The liquid crystal high impedance surface based beam scanning antenna array as claimed in claim 2, wherein the antenna array (1) employs an electrically controlled parasitic antenna array, the rf signal is fed only to the main radiating element, and the parasitic element has no rf feed circuit.

4. The liquid crystal high resistance surface based beam scanning antenna array according to claim 1, characterized in that the antenna elements of the antenna array (1) are rectangular, square or circular microstrip antennas; the antenna elements are arranged along the H-plane.

5. The liquid crystal high impedance surface based beam scanning antenna array according to claim 1, characterized in that the antenna elements of the antenna array (1) are patch antennas.

6. The beam scanning antenna array based on the liquid crystal high-impedance surface as claimed in claim 2, further comprising a feeding device (6), wherein the feeding device (6) adopts probe feeding, microstrip line feeding or slot coupling feeding, and the feeding device (6) is connected with the main radiation unit.

7. The liquid crystal high impedance surface based beam scanning antenna array according to claim 1, characterized in that the high impedance surface (2) is a periodic structure formed by coplanar electromagnetic bandgap cells that are rectangular, mushroom-shaped or cross-shaped.

8. The liquid crystal high impedance surface based beam scanning antenna array according to claim 1, wherein the equivalent dielectric constant of the liquid crystal (3) is changed with the change of the applied electric field or magnetic field.

9. The beam scanning antenna array based on the liquid crystal high-resistance surface as claimed in claim 1, wherein the dielectric plate (5) comprises a first dielectric plate, a second dielectric plate and a third dielectric plate, the first dielectric plate, the second dielectric plate and the third dielectric plate are sequentially arranged from top to bottom, the antenna array (1) is arranged on the upper surface of the first dielectric plate, the second dielectric plate is provided with two liquid crystal grooves, the liquid crystal (3) material is arranged in the liquid crystal grooves, the high-resistance surface (2) is arranged between the lower variable surface of the first dielectric plate and the liquid crystal (3), and the metal ground (4) is arranged between the lower surface of the second dielectric plate and the upper surface of the third dielectric plate.

10. The liquid crystal high impedance surface based beam scanning antenna array according to claim 9, wherein the two liquid crystal cells are respectively arranged right below two parasitic elements of the antenna array (1).

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