Polarization reconfigurable radiation-scattering integrated antenna array based on liquid metal

Abstract

The invention discloses a liquid metal-based polarized reconfigurable radiation-scattering integrated antenna array, which is composed of four sub-arrays, each sub-array comprises a metasurface antenna layer, a metalized ground layer and a feed network layer, the metasurface antenna layer is formed by periodically arranging units and is placed on the upper surface of a first dielectric plate, and the metalized ground layer is arranged on the upper surface of the first dielectric plate. The antenna is mainly used for realizing circular polarization radiation and reducing a radar cross section. The feed network layer is mainly composed of Wilkinson power dividers and is placed on the lower surface of the second dielectric plate; and a metalized ground layer is arranged between the two dielectric plates. In the feed network layer, the signal transmission path of the feed network is changed by regulating the position of the liquid metal, so that the polarization reconfigurable function of the sub-array is realized; according to the invention, the reduced bandwidth of the radar cross section of the antenna array is expanded by arranging the sub-arrays at different heights. According to the invention, the liquid metal is adopted to control the feed network, the reconstruction of antenna polarization is realized, and the working bandwidth of radar scattering reduction is widened through the unequal-height placement of the sub-arrays.

Description

Technical Field

[0001] The invention relates to the technical field of artificial electromagnetic material antennas, and in particular to a polarization-reconfigurable radiation-scattering integrated antenna array based on liquid metal. Background Art

[0002] Antennas are an indispensable part of communication systems. They are both a radiation source of electromagnetic waves and a special scattering source. Research on antennas usually only focuses on the radiation characteristics of antennas or only focuses on their scattering characteristics. In the process of antenna design, the radiation characteristics and scattering characteristics of antennas usually restrict each other. Improving the radiation characteristics will lead to a decrease in the scattering characteristics, and improving the scattering characteristics will lead to a deterioration of the radiation characteristics. With the development of communication technology, the design of modern antenna systems tends to be multifunctional, integrated and intelligent. The design of antenna arrays is no longer satisfied with the improvement of a single radiation performance or the controllability of a single scattering characteristic. Researchers are paying more and more attention to and exploring the integrated design of the radiation and scattering characteristics of antennas. Antennas and arrays with integrated radiation and scattering characteristics have broad development prospects and great research value in civil and military wireless systems.

[0003] Since circularly polarized waves can counteract polarization distortion caused by multipath effects and Faraday rotation effects, circularly polarized antennas are widely used in navigation positioning, Internet of Things, satellite communications and other fields. Reconfigurable antennas can flexibly switch their radiation performance without changing the outer dimensions of the antenna. Combining circularly polarized antennas with reconfigurable technology can greatly improve the performance of circularly polarized antennas. Antenna polarization can be reconfigured by changing the radiator structure of the antenna, loading a reconfigurable polarization conversion surface, and reconfiguring the feeding network. To achieve these goals, researchers loaded PIN diodes in the polarization conversion metasurface to change the polarization of the incident wave, loaded PIN diodes in the antenna's radiation structure, and changed the current distribution on the antenna's radiation structure by controlling the switching state of the switch tube, thereby changing the antenna polarization state. In the feeding network, the phase of the antenna port is changed by switching the PIN diode to achieve the regulation of electromagnetic wave polarization. These methods are implemented using PIN diodes, and their main advantage is fast regulation speed, but there are problems such as reduced antenna efficiency, small power capacity, and DC control network affecting radiation performance due to the loss of PIN diodes. In view of the above problems, the present invention proposes a liquid metal-based polarization reconfigurable radiation and scattering integrated antenna array. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a polarization reconfigurable radiation and scattering integrated antenna array, in which the radiation performance and scattering performance of the antenna do not affect each other, and the polarization mode of the electromagnetic wave radiated by the antenna can be adjusted by controlling the liquid metal in the structure.

[0005] Technical solution: To achieve the above-mentioned purpose, the present invention discloses a liquid metal-based polarization reconfigurable radiation and scattering integrated antenna array, which includes antenna subarrays placed in four quadrants of a rectangular coordinate system, wherein the antenna subarrays include a feed network layer, on which an adjustable phase shifter is provided, and inside the adjustable phase shifter a movable liquid metal segment is provided. By adjusting the position of the liquid metal segment, the signal transmission path of the feed network is changed, so that the polarization mode of the radiated electromagnetic wave of the antenna array can be adjusted.

[0006] The antenna subarray in the first quadrant is used as the initial array, and the latter antenna subarray is rotated 90° relative to the former antenna subarray with the coordinate origin as the center, and the latter antenna subarray is higher than the former antenna subarray by Δh in the Z-axis direction.

[0007] Among them, each antenna subarray includes a supersurface antenna layer, a first dielectric plate, a metallized stratum, and a second dielectric plate; the supersurface antenna layer is located on the upper surface of the first dielectric plate, the metallized stratum is located between the first dielectric plate and the second dielectric plate, the feed network layer is located on the lower surface of the second dielectric plate, and the supersurface antenna layer and the feed network layer are connected through metallized vias.

[0008] Among them, the metasurface antenna layer includes a 4×4 basic unit array, which is divided into four groups of basic unit sub-arrays arranged in a 2×2 periodic manner. One of the basic unit sub-arrays is used as the initial array, and the latter basic unit sub-array is rotated 90° relative to the previous basic unit sub-array with the center of the metasurface antenna layer as the origin.

[0009] Among them, the basic unit includes a square metal patch, which is divided into a small square, three triangles and a trapezoid by four grooves, wherein the four grooves are the first oblique groove, the second oblique groove, the horizontal groove and the vertical groove, respectively. There is a metallized via near a corner of the small square, and the square metal patch is connected to the feed network layer through the metallized via.

[0010] The feeding network layer includes a signal input terminal and four signal output terminals, each of the four signal output terminals is connected to a one-to-four power divider, and the four power distribution networks feed the 4×4 basic unit arrays respectively.

[0011] The feeding network layer includes four groups of one-to-four power dividers, three one-to-two power dividers, one non-adjustable phase shifter, and two adjustable phase shifters. The signal is input from port 1 of the first power divider, port 2 of the first power divider is connected to the input segment port 1 of the second power divider through the non-adjustable phase shifter, and port 3 of the first power divider is connected to the input port 1 of the third power divider through a microstrip line; the output port 2 of the second power divider is connected to the first group of one-to-four power dividers through the first adjustable phase shifter, and the output port 3 of the second power divider is connected to the second group of one-to-four power dividers through a microstrip line; the output port 2 of the third power divider is connected to the third group of one-to-four power dividers through the second adjustable phase shifter, and the output port 3 of the third power divider is connected to the fourth group of one-to-four power dividers through a microstrip line.

[0012] The adjustable phase shifter comprises an input microstrip line, an output microstrip line, a U-shaped microstrip line, and two microfluidic channels, wherein there is liquid metal in the microfluidic channels; wherein there is a gap 1 between the input microstrip line and the output microstrip line, a gap 2 between the input microstrip line and the U-shaped microstrip line, and a gap 3 between the output microstrip line and the U-shaped microstrip line; microfluidic channel 1 is located on gap 1 and gap 2, and microfluidic channel 2 is located on gap 1 and gap 3. When the liquid metals in the two microfluidic channels are moved to the position of gap 1, the input microstrip line and the output microstrip line are turned on; when the liquid metals in the two microfluidic channels are moved to the positions of gap 2 and gap 3 respectively, the input microstrip line is connected to the output microstrip line through the U-shaped microstrip line.

[0013] Among them, when the slot 1 of the two adjustable phase shifters in the feeding network is connected by liquid metal, slot 2 and slot 3 are disconnected, the antenna array radiates right-hand circularly polarized waves; when the slot 1 of the two adjustable phase shifters in the feeding network is disconnected, slot 2 and slot 3 are connected by liquid metal, the antenna array radiates left-hand circularly polarized waves.

[0014] Beneficial effects: The present invention has the following advantages: 1. The present invention proposes a polarization-reconfigurable radiation-scattering integrated antenna array based on liquid metal, which realizes the reconfiguration of left-hand circularly polarized waves and right-hand circularly polarized waves by controlling the position of liquid metal in the feeding network. Compared with PIN diodes, liquid metal can reduce the insertion loss of the feeding network, thereby improving the antenna power capacity and the overall radiation efficiency of the antenna array; 2. Through the sequential rotation of the units in the subarray and the sequential rotation and unequal height setting of the subarray itself, the bandwidth of the radar scattering cross section reduction of the antenna array is widened, the scattering performance of the antenna is improved, and the scattering and radiation performances do not affect each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0016] Figure 2 It is a schematic diagram of the subarray structure of the present invention;

[0017] Figure 3 This is a schematic diagram of the structure of a metasurface antenna in an embodiment of the present invention;

[0018] Figure 4 Schematic diagram of the structure of the feed network layer in an embodiment of the present invention;

[0019] Figure 5 Schematic diagram of the structure of an adjustable phase shifter in an embodiment of the present invention;

[0020] Figure 6 : is an S parameter diagram of the antenna subarray input port in an embodiment of the present invention;

[0021] Figure 7 The antenna gain diagram in the embodiment of the present invention;

[0022] Figure 8 : is an antenna axial ratio diagram in an embodiment of the present invention;

[0023] Fig. 9 This is a diagram showing the radar cross section reduction effect in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is described in detail below in conjunction with the embodiments and drawings.

[0025] like Figure 1 As shown, the polarization reconfigurable radiation scattering integrated antenna array based on liquid metal described in the present invention includes four identical subarrays, which are respectively placed in four quadrants of a rectangular coordinate system, and the subarray 2 located in the second quadrant is obtained by rotating the subarray 1 in the first quadrant 90° with the coordinate origin as the center, the subarray 3 located in the third quadrant is obtained by rotating the subarray 2 in the second quadrant 90° with the coordinate origin as the center, and the subarray 4 located in the fourth quadrant is obtained by rotating the subarray 3 in the third quadrant 90° with the coordinate origin as the center; taking the z-direction position of the subarray 1 as the reference point, the subarray 2, subarray 3 and subarray 4 are respectively higher than the subarray 1 by Δh, 2Δh and 3Δh; wherein Δh is determined by software optimization according to the requirements of scattering performance and its bandwidth, and after optimization in this embodiment, Δh=4.6mm; the scattering performance of the antenna array is improved by sequential rotation of the subarrays and configuration of different heights.

[0026] In order to realize the antenna radiating circularly polarized electromagnetic waves, Figure 1 A more detailed structure of the neutron array is shown in Figure 2As shown. Each subarray includes a metasurface antenna layer 101, a first dielectric plate 102, a metallized ground layer 103, a second dielectric plate 104, and a feed network layer 105. The antenna array is composed of basic units arranged periodically and placed on the upper surface of the 3mm thick first dielectric plate 102. The metallized ground layer 103 is between the first dielectric plate 102 and the second dielectric plate 104. The lower surface of the 0.5mm thick second dielectric plate 104 is the feed network layer 105. The metasurface antenna layer 101 and the feed network layer 105 are connected by metallized vias 106.

[0027] The antenna array and antenna units in the metasurface antenna layer 101 are as follows: Figure 3 As shown. Each subarray includes 16 basic units of the same structure arranged in four rows and four columns; the 16 units are divided into four groups, each group includes four units in two rows and two columns, the second group of four units is obtained by rotating the first group of four units by 90° with the subarray as the center, the third group of four units is obtained by rotating the second group of four units by 90° with the subarray as the center, and the fourth group of four units is obtained by rotating the third group of four units by 90° with the subarray as the center; each unit is etched on the upper surface of the first dielectric plate 102. The square patch is divided into a small positive patch by four grooves. A square, three triangles and a trapezoid, wherein the four grooves are the first oblique groove, the second oblique groove, the horizontal groove and the vertical groove respectively; a metallized via 106 is provided near a corner of the small square, and the metallized via 106 passes through the first dielectric layer 102, the metallized ground layer 103 and the second dielectric layer 104, and is finally connected to the feed network layer 105 located at the bottom layer of the unit, wherein l1=12mm, l2=8.5mm, l3=2.75mm, l4=4.13mm, w1=0.6mm, w2=0.8mm, w3=1.5mm.

[0028] The polarization reconfigurability of the antenna is achieved through the adjustable phase shifter of the feed network layer. The structural diagram of the feed network layer is shown in Figure 4The invention comprises four groups of one-to-four power dividers (207, 208, 209, 210), three one-to-two power dividers (201, 203, 204), one non-adjustable phase shifter (202), and two adjustable phase shifters (205, 206), wherein a 100 ohm resistor is connected between the two output ports of each one-to-two power divider; a signal is input from port 1 of the first power divider 201, and port 2 of the first power divider 201 is connected to the input port 1 of the second power divider 203 through the non-adjustable phase shifter 202; the first power divider 201 Port 3 is connected to the input port 1 of the third power divider 204 through a microstrip line; the output port 2 of the second power divider 203 is connected to the first group of one-to-four power dividers 207 through the first adjustable phase shifter 205, and the output port 3 of the second power divider 203 is connected to the second group of one-to-four power divider 208 through a microstrip line; the output port 2 of the third power divider 204 is connected to the third group of one-to-four power divider 209 through the second adjustable phase shifter 206, and the output port 3 of the third power divider 204 is connected to the fourth group of one-to-four power divider 210 through a microstrip line.

[0029] The power distributors 208, 209 and 210 are obtained by rotating the power distributor 207 by 90°, 180° and 270° respectively with the center of the feed network layer as the origin.

[0030] The structure of the adjustable phase shifters 205 and 206 in the feed network layer is as follows: Figure 5As shown, it includes an input microstrip line 301, an output microstrip line 302, a U-shaped microstrip line 303, two microfluidic channels 307 and 308, and two sections of liquid metal 309 and 310; there is a gap 304 between the input microstrip line 301 and the output microstrip line 302, a gap 305 between the input microstrip line 301 and the U-shaped microstrip line 303, and a gap 306 between the output microstrip line 302 and the U-shaped microstrip line 303; the microfluidic channel 307 is located above the gap 304 and the gap 306, and the liquid metal 309 is in the channel; the microfluidic channel 308 is located above the gap 304 and the gap 305, and the liquid metal 310 is in the channel; when the microfluidic The liquid metal 309 in the channel 307 and the liquid metal 310 in the microfluidic channel 308 are both located on the gap 304, and the adjustable phase shifter works in state 1, that is, the input microstrip line 301 and the output microstrip line are connected 302, and the U-shaped microstrip line 303 is disconnected. At this time, the antenna array radiates right-handed circularly polarized waves; when the liquid metal 309 in the microfluidic channel 307 is pushed onto the gap 306 by an external drive, and the liquid metal 310 in the microfluidic channel 308 is pushed onto the gap 305 by an external drive, the adjustable phase shifter works in state 2, that is, the input microstrip line 301 is connected to the output microstrip line 302 through the U-shaped microstrip and 303, and at this time, the antenna array radiates left-handed circularly polarized waves.

[0031] Antenna array |S 11 |As Figure 6 When the antenna array radiates right-hand circularly polarized waves, |S 11 | Less than -10dB in the 8.61-12GHz frequency band, when the antenna array radiates left-hand circularly polarized waves, |S 11 |Less than -10dB in the 9.96-11.99GHz frequency band.

[0032] The gain curve of the antenna array is as follows: Figure 7 When the antenna array radiates right-hand circular polarization, the peak gain is 15dBic, and the 3dB gain frequency range is 9.83-12.56GHz; when the antenna array radiates left-hand circular polarization, the peak gain of the antenna array is 15dBic, and the 3dB gain frequency range is 9.51-12.31GHz.

[0033] The axial ratio curve of the antenna array is as follows: Figure 8 As shown, when the antenna array radiates right-hand circular polarization, the frequency range in which the axial ratio is less than 3dB is 8-12.23GHz; when the antenna array radiates left-hand circular polarization, the frequency range in which the axial ratio is less than 3dB is 8.76-13.16GHz.

[0034] The simulation results of the monostatic RCSR of the antenna array with frequency are shown in Figure 2. Fig. 9As shown in the figure, the results show that the frequency range of radar cross section reduction greater than 10dB covers 6.33-27.09GHz, and the relative bandwidth is 124.23%. It should be noted that when a uniform plane wave of x-polarization or y-polarization is vertically incident on the antenna surface, the radar cross section reduction curve of the antenna array is the same regardless of whether the antenna radiates right-hand circularly polarized or left-hand circularly polarized waves; that is, the radiation performance and scattering performance of the antenna array do not affect each other.

[0035] The present invention proposes a polarization reconfigurable radiation and scattering integrated antenna array based on liquid metal, which realizes the reconfiguration of left-hand circularly polarized waves and right-hand circularly polarized waves by controlling the position of liquid metal in the feed network. Compared with PIN diodes, liquid metal can reduce the insertion loss of the feed network, thereby improving the antenna power capacity and the overall radiation efficiency of the antenna array. Through the sequential rotation of the units in the subarray and the sequential rotation and unequal height setting of the subarray itself, the bandwidth of the radar scattering cross section reduction of the antenna array is widened, the scattering performance of the antenna is improved, and the scattering and radiation performances do not affect each other.

Claims

1. A liquid metal-based polarization reconfigurable radiation and scattering integrated antenna array, comprising antenna subarrays placed in four quadrants of a rectangular coordinate system, It is characterized in that The antenna subarray includes a feed network layer, on which an adjustable phase shifter is provided, and inside the adjustable phase shifter is a movable liquid metal segment. The signal transmission path of the feed network is changed by adjusting the position of the liquid metal segment, so that the antenna array can achieve adjustable polarization of radiated electromagnetic waves.

2. According to claim 1, a liquid metal-based polarization reconfigurable radiation scattering integrated antenna array, It is characterized in that The antenna subarray in the first quadrant is used as the initial array. The next antenna subarray is rotated 90° relative to the previous antenna subarray with the coordinate origin as the center, and the next antenna subarray is higher than the previous antenna subarray by Δh in the Z-axis direction.

3. According to claim 1, a liquid metal-based polarization reconfigurable radiation scattering integrated antenna array, It is characterized in that Each antenna subarray includes a supersurface antenna layer, a first dielectric plate, a metallized stratum, and a second dielectric plate; the supersurface antenna layer is located on the upper surface of the first dielectric plate, the metallized stratum is located between the first dielectric plate and the second dielectric plate, the feed network layer is located on the lower surface of the second dielectric plate, and the supersurface antenna layer and the feed network layer are connected through metallized vias.

4. According to claim 3, the liquid metal-based polarization reconfigurable radiation scattering integrated antenna array, It is characterized in that The metasurface antenna layer includes a 4×4 basic unit array, which is divided into four groups of 2×2 periodically arranged basic unit subarrays. One of the basic unit subarrays is used as the initial array, and the latter basic unit subarray is rotated 90° relative to the previous basic unit subarray with the center of the metasurface antenna layer as the origin.

5. According to claim 4, the liquid metal-based polarization reconfigurable radiation scattering integrated antenna array, It is characterized in that The basic unit includes a square metal patch, which is divided into a small square, three triangles and a trapezoid by four grooves, wherein the four grooves are a first oblique groove, a second oblique groove, a horizontal groove and a vertical groove, respectively. There is a metallized via near a corner of the small square, and the square metal patch is connected to the feed network layer through the metallized via.

6. According to claim 4, the liquid metal-based polarization reconfigurable radiation scattering integrated antenna array, It is characterized in that The feeding network layer includes a signal input terminal and four signal output terminals. The four signal output terminals are all connected to a one-to-four power distributor. The four power distribution networks feed the 4×4 basic unit arrays respectively.

7. According to claim 4, the liquid metal-based polarization reconfigurable radiation scattering integrated antenna array, It is characterized in that The feeding network layer includes four groups of one-to-four power dividers, three one-to-two power dividers, one non-adjustable phase shifter, and two adjustable phase shifters. The signal is input from port 1 of the first power divider, port 2 of the first power divider is connected to input section port 1 of the second power divider through the non-adjustable phase shifter, and port 3 of the first power divider is connected to input port 1 of the third power divider through a microstrip line; output port 2 of the second power divider is connected to the first group of one-to-four power dividers through the first adjustable phase shifter, and output port 3 of the second power divider is connected to the second group of one-to-four power dividers through a microstrip line; output port 2 of the third power divider is connected to the third group of one-to-four power dividers through the second adjustable phase shifter, and output port 3 of the third power divider is connected to the fourth group of one-to-four power dividers through a microstrip line.

8. The liquid metal-based polarization reconfigurable radiation scattering integrated antenna array according to claim 1 or 7, It is characterized in that The adjustable phase shifter comprises an input microstrip line, an output microstrip line, a U-shaped microstrip line, and two microfluidic channels, wherein liquid metal is contained in the microfluidic channels; wherein a gap 1 is provided between the input microstrip line and the output microstrip line, a gap 2 is provided between the input microstrip line and the U-shaped microstrip line, and a gap 3 is provided between the output microstrip line and the U-shaped microstrip line; microfluidic channel 1 is located on gap 1 and gap 2, and microfluidic channel 2 is located on gap 1 and gap 3; when the liquid metals in the two microfluidic channels are moved to the position of gap 1, the input microstrip line and the output microstrip line are turned on; when the liquid metals in the two microfluidic channels are moved to the positions of gap 2 and gap 3 respectively, the input microstrip line is connected to the output microstrip line via the U-shaped microstrip line.

9. The liquid metal-based polarization reconfigurable radiation and scattering integrated antenna array according to claim 8, It is characterized in that When the slot 1 of the two adjustable phase shifters in the feeding network is connected by liquid metal, and the slot 2 and the slot 3 are disconnected, the antenna array radiates right-hand circularly polarized waves; when the slot 1 of the two adjustable phase shifters in the feeding network is disconnected, and the slot 2 and the slot 3 are connected by liquid metal, the antenna array radiates left-hand circularly polarized waves.

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