Pattern-frequency reconfigurable smart robotic conformal antenna based on liquid crystal material

Abstract

The pattern-frequency reconfigurable intelligent robot conformal antenna based on liquid crystal material comprises six liquid crystal phase shift antenna tuning units and six hexagonal power division feeding network antenna tuning units which are electrically and mechanically connected with the six liquid crystal phase shift antenna tuning units simultaneously, and the planes where the liquid crystal phase shift antenna tuning units and the six power division feeding network antenna tuning units are located have an included angle at the mechanical connection. The reconfigurable antenna can reconfigure the pattern in a range of 360 degrees in the azimuth plane, realize the beam coverage in a certain elevation angle range, and through the biasing of the varactor diode by the direct current voltage, the frequency tuning can be realized, and the realization means is simple.

Description

Technical Field

[0001] This invention belongs to the field of electronic equipment technology, specifically relating to reconfigurable and tunable antenna technology, and more specifically to a pattern-frequency reconfigurable conformal antenna for intelligent robots based on liquid crystal materials. Background Technology

[0002] Reconfigurability is a novel type of antenna research. Compared to traditional antennas, reconfigurable functions can be achieved through various methods such as electronic control, magnetic control, optical control, and mechanical control. Among these, electronic control is relatively easy to implement for reconfigurable antennas due to advancements in chip technology. By utilizing reconfigurable technology, multiple different functions can be integrated onto a single antenna, ensuring compatibility with multiple wireless devices, enhancing the utilization of limited space, and reducing manufacturing costs and process complexity. Depending on the application scenario, reconfigurability can be tailored to different targets, generally categorized into polarization-pattern reconfigurability, frequency-polarization reconfigurability, frequency-pattern reconfigurability, and frequency-polarization-pattern reconfigurability, among others. Facing increasingly complex application requirements, reconfigurable antennas are developing towards multi-functionality and independent reconfigurability.

[0003] Deng Lianwen et al. (Deng Lianwen, Zhen Liying, Wang Haiyue et al. Wideband Reconfigurable Microstrip Antenna [P]. Hunan Province: CN112736456A, 2021-04-30.) described a wideband tunable microstrip antenna based on varactor diodes. A tuning structure is formed by two sets of patches of different sizes, parasitic patches, and varactor diodes, combined with a tunable feed network to achieve frequency reconfiguration within a wide bandwidth. The main patch and parasitic patch structure can effectively achieve tuning within a certain frequency range and exhibits good return loss, enhancing the applicability of modern communication equipment, reducing costs, and enabling multi-functional system integration.

[0004] Bai Tianming (Bai Tianming. Design of Cylindrical Conformal Phased Array Antenna Based on Liquid Crystal Material [D]. University of Electronic Science and Technology of China, 2022) designed a cylindrical conformal phased array antenna based on a liquid crystal phase shifter, achieving equal-gain radiation at a 60° angle on the cylindrical surface. Multiple antenna combinations were used to achieve full circumferential beam coverage on the cylindrical surface. However, the antenna's radiation and reception are omnidirectional, which leads to an increase in the overall noise figure of the system. Furthermore, multiple two-dimensional cylindrical conformal antennas are required for both radiation and reception, resulting in higher manufacturing costs and a more complex bias network. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention discloses a pattern-frequency reconfigurable conformal antenna for intelligent robots based on liquid crystal materials.

[0006] The conformal antenna for a pattern-frequency reconfigurable intelligent robot based on liquid crystal material, as described in this invention, includes six liquid crystal phase-shifting antenna tuning units and a hexagonal power divider network antenna tuning unit that is electrically and mechanically connected to the six liquid crystal phase-shifting antenna tuning units. The six liquid crystal phase-shifting antenna tuning units are each connected to one side of the power divider network antenna tuning unit, and adjacent two liquid crystal phase-shifting antenna tuning units are also connected by a boundary. The planes where the liquid crystal phase-shifting antenna tuning units and the hexagonal power divider network antenna tuning units are located have an angle at the mechanical connection, with the angle ranging from 9 to 13 degrees.

[0007] Preferably, the liquid crystal phase-shifting antenna tuning unit includes a first back dielectric substrate, a slotted dielectric substrate and a liquid crystal filling slot disposed on the back dielectric substrate, a liquid crystal microstrip line disposed between the first back dielectric substrate and the liquid crystal filling slot, a first quarter-wavelength matching microstrip line disposed between the back dielectric substrate and the slotted dielectric substrate and connected to the first end of the liquid crystal microstrip line, a first metal dielectric filling hole electrode layer disposed on the side of the slotted dielectric substrate and the liquid crystal filling slot 13 away from the first back dielectric substrate, a first front band hole dielectric substrate disposed on the side of the first metal dielectric filling hole electrode layer away from the first back dielectric substrate, and a first front band hole dielectric substrate disposed on the side of the first front band hole dielectric substrate away from the first back dielectric substrate. The system comprises a main metal patch and a first parasitic metal patch, multiple first varactor diodes connected in parallel on the first parasitic metal patch, and a first feed metal cylinder connected on the first main metal patch; a first dielectric filling hole is provided on the first metal dielectric filling hole electrode layer; the second end of a specific impedance microstrip line is connected to the first feed metal cylinder passing through the first dielectric filling hole; multiple first varactor diodes are equidistantly welded on a straight line to form a first varactor diode array; the first feed metal cylinder is located on the central axis of the first varactor diode array; and the first quarter-wavelength impedance matching microstrip line serves as the electrical connection terminal between the liquid crystal phase-shift antenna tuning unit and the power divider feed network antenna tuning unit.

[0008] Preferably, the first parasitic metal patch is a rounded rectangular metal patch.

[0009] Preferably, the liquid crystal microstrip line is a planar spiral shape, with the first end located at the outer edge of the planar spiral and the second end located at the center of the spiral. The second end is connected to the first feeding metal cylinder 10 through a microstrip line with a specific impedance.

[0010] Preferably, the power divider network antenna tuning unit includes a second back dielectric substrate, a metal circuit layer disposed on the second back dielectric substrate, a dielectric substrate layer disposed on the metal circuit layer away from the second back dielectric substrate, a second metal dielectric filling hole electrode layer disposed on the dielectric substrate layer away from the back dielectric layer, a second front band hole dielectric substrate disposed on the second metal dielectric filling hole electrode layer away from the second back dielectric substrate, a second main metal patch and a second parasitic metal patch disposed on the second front band hole dielectric substrate away from the back dielectric substrate, a plurality of packaged second varactor diodes connected in parallel between the two metal patches, and a second feed metal cylinder welded at a certain position on the second main metal patch; a second dielectric filling hole is provided on the second metal dielectric filling hole electrode layer, a reference connection microstrip line is connected to the second feed metal cylinder passing through the second dielectric filling hole, a plurality of second varactor diodes are equidistantly welded on a straight line to form a second varactor diode array, and the second feed metal cylinder is located on the central axis of the second varactor diode array; A microstrip feed network connected to six liquid crystal phase-shift antenna tuning units is provided on the metal circuit layer.

[0011] Preferably, the microstrip feed network includes six Wilkinson power dividers, twelve reference connection microstrip lines, and six second quarter-wavelength matched microstrip lines located on the six sides of the antenna tuning unit of the power divider feed network. Each Wilkinson power divider includes one input terminal and two output terminals. The first Wilkinson power divider's input terminal is the radio frequency signal input terminal, directly connected to the input terminals of the second and third Wilkinson power dividers via two reference connection microstrip lines. One output terminal of the second Wilkinson power divider is connected to the reference connection microstrip lines. The stripline passes through the second front-hole dielectric substrate, the hole dielectric layer, and the dielectric substrate layer, and connects to the second feed metal cylinder. Another output terminal is connected to the input terminal of the fourth Wilkinson power divider. The two output terminals of the third Wilkinson power divider are respectively connected to the input terminals of the fifth and sixth Wilkinson power dividers. The six output terminals of the fourth, fifth, and sixth Wilkinson power dividers are respectively connected to the second quarter-wavelength matching microstrip lines on the six sides of the power divider feed network antenna tuning unit through reference microstrip lines.

[0012] Preferably, the second parasitic metal patch is a rounded rectangular metal patch.

[0013] The beneficial effects of this invention are: 1. The reconfigurable antenna of the present invention can reconfigure the radiation pattern within a 360° range on the azimuth plane to achieve beam coverage within a certain elevation angle range; and frequency tuning can be achieved by biasing the varactor diode with DC voltage, which is a simple implementation method.

[0014] 2. This invention can achieve single-beam scanning within a frequency band. When the covered operating frequency band is 3.5-3.75GHz, the return loss is greater than 12dB and the impedance bandwidth exceeds 17.8%. It can be applied to various working scenarios, such as Internet of Things and indoor high-speed communication.

[0015] 3. The reconfigurable conformal antenna of this invention consists of six liquid crystal phase-shifting antenna tuning units and one power divider feed network antenna tuning unit, all of which can be implemented by stacking PCB boards. The antennas are symmetrical in shape, making them easy to install on the head of intelligent robots to enable communication for intelligent robots. The antennas are low in cost and simple to manufacture. The overall miniaturization advantage is obvious. Moreover, the size of the reconfigurable unit is about half a wavelength, which can be used in phased array applications. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of a specific embodiment of the reconfigurable conformal antenna described in this invention.

[0017] Figure 2 This is a schematic diagram of a specific embodiment of the liquid crystal phase-shifting antenna tuning unit described in this invention; Figure 3 This is a schematic diagram of a specific embodiment of the antenna tuning unit of the power divider feed network described in this invention; Figure 4 This is a schematic diagram of the equivalent circuit of a specific embodiment of the liquid crystal phase-shifting antenna tuning unit of the present invention; Figure 5 This is a schematic diagram of the equivalent circuit of a specific embodiment of the power divider feed network antenna tuning unit of the present invention; Figure 6 This is a schematic diagram of the structural parameters of a specific embodiment of the liquid crystal phase-shifting antenna tuning unit of the present invention; Figure 7 This is a schematic diagram of the structural parameters of a specific embodiment of the antenna tuning unit of the power divider feed network described in this invention; Figure 8 This is a schematic diagram of an equivalent circuit of a specific embodiment of the metal circuit layer described in this invention; Figure 9 This is a simulation result of antenna return loss in a specific embodiment of the present invention; Figure 10 The simulation results of the antenna in this invention at different operating frequencies correspond to various radiation states. Figure 11 The simulation results of the peak actual gain of the antenna in the present invention at different operating frequencies for each radiation state are shown in the figure. Figure 12 The figure shows the simulation results of the radiation efficiency of the antenna in this invention at different operating frequencies for each radiation state.

[0018] The figures are labeled as follows: 1. Liquid crystal phase-shifting antenna tuning unit; 2. Power divider feed network antenna tuning unit; 3. Liquid crystal microstrip line; 4. Slot dielectric substrate; 5. First metal dielectric-filled via electrode layer; 6. First front-band via dielectric substrate; 7. First main metal patch; 8. First parasitic metal patch; 9. First varactor diode; 10. First feed metal cylinder; 11. Specific impedance microstrip line; 12. First dielectric-filled via; 13. Liquid crystal-filled slot; 14. First quarter-wavelength matching microstrip line; 15. Dielectric substrate layer; 16. Wilkinson power divider; 17. Second quarter-wavelength matching microstrip line; 18. Second metal dielectric-filled via electrode layer; 19. Second dielectric-filled via; 20. Second front-band via dielectric substrate; 21. Second main metal patch; 22. Second parasitic metal patch; 23. Second varactor diode; 24. Second feed metal cylinder; 25. Reference connection microstrip line. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in further detail below.

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] A schematic diagram of the overall structure of a specific embodiment of the conformal antenna for a pattern-frequency reconfigurable intelligent robot based on liquid crystal material described in this invention is shown below. Figure 1 As shown, the antenna comprises six hexagonal liquid crystal phase-shifting antenna tuning units 1 and one hexagonal power divider network antenna tuning unit 2. The six liquid crystal phase-shifting antenna tuning units 1 are each connected to one side of the power divider network antenna tuning unit 2, and adjacent liquid crystal phase-shifting antenna tuning units are also connected by a boundary. The planes on which the hexagonal liquid crystal phase-shifting antenna tuning units 1 and 2 are located have an angle that shifts the maximum radiation direction of the hexagonal liquid crystal phase-shifting antenna tuning unit by a certain angle, thus making the antenna gain relatively flat within the beam scanning range. The angle ranges from 9 to 13 degrees, forming a combination resembling a partial soccer ball surface. The angle can be calculated using the following formula:

[0022] The side length of the hexagon is D = 23.43 mm, and the radius of the conformal sphere is R = 210.00 mm.

[0023] The structural schematic diagram of the liquid crystal phase-shifting antenna tuning unit 1 is shown below. Figure 2 As shown, it includes a first back dielectric substrate, a slot dielectric substrate 4 and a liquid crystal filling slot 13 disposed on the back dielectric substrate, a liquid crystal microstrip line 3 disposed between the first back dielectric substrate and the liquid crystal filling slot 13, a first quarter-wavelength matching microstrip line 14 disposed between the back dielectric substrate and the slot dielectric substrate 4 and connected to the first end of the liquid crystal microstrip line 3, a first specific impedance microstrip line 11 disposed between the back dielectric substrate and the slot dielectric substrate 4 and connected to the second end of the liquid crystal microstrip line 3, a first metal dielectric filling hole electrode layer 5 disposed on the side of the slot dielectric substrate 4 and the liquid crystal filling slot 13 away from the first back dielectric substrate, a first front hole dielectric substrate 6 disposed on the side of the first metal dielectric filling hole electrode layer 5 away from the first back dielectric substrate, and a first front hole dielectric substrate 6 disposed on the first front hole dielectric substrate 6. The first main metal patch 7 and the first parasitic metal patch 8 are located on the side away from the first back dielectric substrate, and three first varactor diodes 9 are soldered to the first parasitic metal patch 8 and a first feed metal cylinder 10 is soldered to the first main metal patch 7. A first dielectric filling hole 12 is provided on the first metal dielectric filling hole electrode layer 5 for connecting the second end of the specific impedance microstrip line 11 to the first feed metal cylinder 10 passing through the first dielectric filling hole 12. The three first varactor diodes 9 are equidistantly connected in parallel on a straight line to form a first varactor diode array. The first feed metal cylinder 10 is located on the central axis of the first varactor diode array. The first parasitic metal patch 8 and the first main metal patch 7 are a certain distance apart, usually located near the solder joint of the three varactor diodes. After liquid crystal is filled into the liquid crystal filling slot 13, the liquid crystal microstrip line 11 is connected to the second end of the liquid crystal microstrip line 3 of the encapsulated liquid crystal bar, and is connected to one of the second quarter-wavelength impedance matching microstrip lines 17 of the power divider feed network antenna tuning unit 2 through the first quarter-wavelength impedance matching microstrip line 14.

[0024] The first parasitic metal patch 8 can be a rounded rectangular metal patch with an arc shape at the boundary vertices, while the first main metal patch 7 adopts a traditional right-angled rectangular shape. Compared with the square parasitic patch, the first parasitic metal patch 8 has higher return loss, thereby enhancing the notch filtering capability in the tuning band. The varactor diode's capacitance value can be controlled by an external bias voltage. The first feed metal cylinder 10 can be welded to the central axis of the boundary where the three first varactor diodes are mounted on the first main metal patch 7, at a distance of d1 = 3.35 mm from this boundary. A slot dielectric substrate covers the liquid crystal filling slot. By filling the liquid crystal filling slot with liquid crystal and applying a voltage between the first metal dielectric filling hole electrode layer 5 and the liquid crystal microstrip line 3 during use, the dielectric constant of the liquid crystal is adjusted, changing the phase constant of the liquid crystal microstrip line, thereby achieving phase modulation and signal phase shifting. A quarter-wavelength matched microstrip line specifically refers to a section whose characteristic impedance is the square root of the product of the characteristic impedances of the microstrip lines connected at both ends, and whose length is one-quarter of the waveguide wavelength of this microstrip line.

[0025] The equivalent circuit diagram of the liquid crystal phase-shift antenna tuning unit 1 is as follows: Figure 4 As shown, in one specific embodiment, since the first varactor diode does not have a packaged capacitor, the first varactor diode can be simplified to... Figure 4 The series equivalent circuit shown in the dashed box, with inductance Ls1=0.7nH, resistance Rs1=2.5Ω, and capacitance Cx1=0.41pF~0.81pF, exhibits capacitive impedance within the operating frequency band. The first main metal patch 7 on the liquid crystal phase-shifting antenna tuning unit is connected to the first parasitic metal patch 8 through three first varactor diodes 9. The main metal patch and the parasitic metal patch can be regarded as parallel circuits with radiative conductivities Gr1 and Gr2 and parasitic capacitances jB1 and jB2, respectively. The two ends of the first varactor diode are connected by equivalent microstrip lines of length d1+d2 and L2, respectively, to form the entire tuning circuit structure. The sum of d1 and d2 is the length L1 of the first main metal patch 7. L1 and L2 are the lengths of the first main metal patch and the first parasitic metal patch, respectively. The length of the metal patch refers to the side length perpendicular to the direction of the varactor diode array.

[0026] By applying a negative voltage between the first main metal patch 7 and the first parasitic metal patch 8 to reverse bias the varactor diode, the overall capacitive impedance of the varactor diode is changed, thereby adjusting the equivalent microstrip line length of the patch relative to the feed terminal in the tuning structure. This changes the effective radiating patch length of the patch antenna, thereby achieving frequency tuning within the range of 3.5 GHz to 3.75 GHz.

[0027] The power divider feed network antenna tuning unit 2 includes a second back dielectric substrate, a metal circuit layer disposed on the second back dielectric substrate, a dielectric substrate layer 15 disposed on the metal circuit layer away from the back dielectric substrate, a second metal dielectric filling hole electrode layer 18 disposed on the dielectric substrate layer away from the back dielectric layer, a second front band hole dielectric substrate 20 disposed on the second metal dielectric filling hole electrode layer 18 away from the second back dielectric substrate, a second main metal patch 21 and a second parasitic metal patch 22 disposed on the second front band hole dielectric substrate 20 away from the back dielectric substrate, three packaged second varactor diodes 23 connected in parallel between the two metal patches, and a second feed metal cylinder 24 welded at a certain position on the second main metal patch; a second dielectric filling hole 19 is provided on the second metal dielectric filling hole electrode layer 18 for the reference connection microstrip line 25 to connect to the second feed metal cylinder 24 passing through the second dielectric filling hole 19. Three second varactor diodes 23 are equidistantly welded on a straight line to form a second varactor diode array, and the second feed metal cylinder 24 is located on the central axis of the second varactor diode array.

[0028] The equivalent circuit diagram of the power divider network antenna tuning unit 2 is as follows: Figure 5 As shown, similar to the equivalent circuit of the liquid crystal phase-shifting antenna tuning unit 1, the three parallel second varactor diodes can be simplified to... Figure 5 The series equivalent circuit shown in the dashed box, with inductance Ls2=0.7nH, resistance Rs2=2.5Ω, and capacitance Cx2=0.41pF~0.81pF, exhibits capacitive impedance within the operating frequency band. The second main metal patch 21 on the power divider network antenna tuning unit is connected to the second parasitic metal patch 22 through three second varactor diodes 23. The main metal patch and the parasitic patch can be regarded as parallel circuits with radiation conductance Gr3, Gr4 and parasitic capacitance jB3, jB4, respectively. The two ends of the second varactor diodes are connected through equivalent microstrip lines of length d3+d4 and L4 to form the entire tuning circuit structure. The sum of d3+d4 is the length L3 of the second main metal patch 21, and L3 and L4 are the lengths of the second main metal patch and the second parasitic metal patch, respectively.

[0029] The microstrip feed network on the metal circuit layer distributes the input RF signal to the six liquid crystal phase-shift antenna tuning units and the antenna tuning units on the power divider feed network. Theoretically, this distribution is 12.5% ​​of the signal in the six liquid crystal phase-shift antenna tuning units and 25.0% in the power divider feed antenna tuning units. In one specific embodiment, it includes six Wilkinson power dividers 16, twelve reference connection microstrip lines 25, and six second quarter-wavelength matching microstrip lines 17 located on the six sides of the antenna tuning units of the power divider feed network. Each Wilkinson power divider includes one input terminal and two output terminals. The first Wilkinson power divider 161 has an RF signal input terminal, and its two output terminals are directly connected to the input terminals of the second Wilkinson power divider 162 and the third Wilkinson power divider 163 via two reference connection microstrip lines. One output terminal of the second Wilkinson power divider passes through a reference connection microstrip line... The second front-hole dielectric substrate 20, the hole dielectric layer, and the dielectric substrate layer 15 are connected to the second feed metal cylinder 24, and another output terminal is connected to the input terminal of the fourth Wilkinson power divider; the two output terminals of the third Wilkinson power divider 163 are respectively connected to the input terminals of the fifth Wilkinson power divider and the sixth Wilkinson power divider; the six output terminals of the fourth Wilkinson power divider 164, the fifth Wilkinson power divider 165, and the sixth Wilkinson power divider 166 are respectively connected to the second quarter-wavelength matching microstrip line 17 on the six sides of the power divider feed network antenna tuning unit through the reference microstrip line 25, and its equivalent circuit is as follows. Figure 8 As shown, Figure 8 In this context, Z0 and Z1 represent the equivalent resistance of the microstrip line with characteristic impedances of 50 and 31 ohms, respectively, and R is the isolation resistance of the Wilkinson power divider, which can be taken as 100 ohms. Figure 8 In the diagram, the equivalent resistances of the microstrip lines that do not belong to the Wilkinson power divider within the dashed box and are labeled Z0 and Z1 represent the twelve reference microstrip lines 25 and the six second quarter-wavelength matching microstrip lines 17, respectively.

[0030] The first end of the second quarter-wavelength matching microstrip line 17 is connected to the reference microstrip line 25 and the second end is connected to the first quarter-wavelength matching microstrip line 14 of the liquid crystal phase-shift antenna tuning unit 1 to form a complete circuit.

[0031] The equivalent resistance formed by the combination of the liquid crystal microstrip line 3, the first quarter-wavelength matching microstrip line 14, and the second quarter-wavelength matching microstrip line 17 is matched with the reference microstrip line 25. The impedance matching with the reference microstrip line 25 can be achieved by appropriately adjusting the length of the first quarter-wavelength matching microstrip line 17.

[0032] Similar to the liquid crystal phase-shift antenna tuning unit 1, the second main metal patch 21 on the power divider feed network antenna tuning unit 2 is connected to the second parasitic metal patch 22 through three second varactor diodes 23 to form a tuning structure. By controlling the bias voltage of the first varactor diode 9 and the second varactor diode 23 on the liquid crystal phase-shift antenna tuning unit 1 and the power divider feed network antenna tuning unit 2 and making each bias voltage value equal, the capacitance value of each varactor diode is changed, thereby changing the overall capacitive impedance of the packaged diode. This achieves the purpose of adjusting the equivalent microstrip length of the parasitic metal patch and the varactor diode relative to the feed metal cylinder, so that the effective radiating patch length of the tuned structure changes, thereby realizing the frequency tuning function.

[0033] Common planar or cylindrical phased array antennas suffer from low scanning angles. Leveraging the half-space or even full-space beam scanning capabilities of spherical array antennas, this invention employs a spherical conformal scheme for its reconfigurable antenna. Combined with an antenna constructed using phase shifters based on liquid crystal materials, a reconfigurable spherical conformal antenna with six phase-shifting antenna elements and one power-dividing network antenna element is designed. This achieves a beam scanning range of ±45° and full circumferential beam coverage, a maximum achievable gain exceeding 7dBi, and a maximum radiation efficiency exceeding 40%. Compared to previously reported 5×5 liquid crystal phased array antennas with a circumferential ±30° beam scanning range and an achievable gain of 18dBi, this invention offers a larger beam scanning range, uses fewer elements, has a simpler structure, and provides considerable gain. Furthermore, the use of parasitic metal patches with rounded corners results in a return loss exceeding 12dB and a maximum radiation efficiency exceeding 40% within the operating frequency band.

[0034] The power divider network antenna tuning unit 2 is located at the center of the partial soccer ball surface assembly. The input terminal of the first Wilkinson power divider serves as the input terminal of the power divider network antenna tuning unit. By controlling the bias voltage of each unit, the radiation output achieves four radiation states and three different frequencies: at 3.5 GHz, states S1-S4: S1 (+45°Front End-Fire), S2 (-45°Back End-Fire), S3 (+45°Right End-Fire), S4 (-45°Left End-Fire); at 3.625 GHz, states S5-S8: S5 (+45°Front End-Fire), S6 (-45°Back End-Fire), S7 (+45°Right End-Fire), S8 (-45°Left End-Fire); at 3.75 GHz, states S9-S12: S9 (+45°Front End-Fire), S6 (-45°Back End-Fire), S7 (+45°Right End-Fire), S8 (-45°Left End-Fire); at 3.75 GHz, states S9 (+45°Front End-Fire), S6 (-45°Back End-Fire), S7 (+45°Right End-Fire), S8 (-45°Left End-Fire). S10 (-45° Back End-Fire), S11 (+45° Right End-Fire), and S12 (-45° Left End-Fire). Front End-Fire, Back End-Fire, Right End-Fire, and Left End-Fire represent the front-end firing array, rear-end firing array, right-end firing array, and left-end firing array, respectively.

[0035] Example 1 The overall dimensions of the conformal antenna for the pattern-frequency reconfigurable intelligent robot based on liquid crystal material are 120.9mm × 116.3mm × 9.3mm. Assuming the antenna center operating frequency f = 3.625GHz, and the corresponding vacuum wavelength λ0, then 120.9mm × 116.3mm × 9.3mm corresponds to 1.461λ0 * 1.405λ0 * 0.112λ0. The first back dielectric substrate, the first metal dielectric-filled via electrode layer, the slot dielectric substrate, and the first front via dielectric substrate in the liquid crystal phase-shift antenna tuning unit are all Rogers TMM4, using a regular hexagonal shape with a side length of 23.4mm, a dielectric constant of 4.5, and a loss tangent of 0.002. The thickness of the first back dielectric substrate is 0.2mm, the thickness of the slot dielectric substrate is 0.19mm, and the thickness of the first front via dielectric substrate is 1.6mm. The width of the quarter-wavelength matching microstrip line is... W11 = 0.4mm, length 4.51mm, characteristic impedance 70.7 ohms; the liquid crystal microstrip line 3 adopts a U-shaped shape, which allows the signal to be input from the outer end and output from the center, suitable for the wiring of the spherical conformal antenna power divider circuit and the arrangement of the antenna tuning unit feed at the center of the geometry, with a width of w2= 0.78mm, characteristic impedance is 20 ohms, chamfer size is w3 = 0.78mm, spacing is g1 = 0.32mm and minimum unit size is a = 4.64mm, the first end of the U-shaped liquid crystal microstrip line 3 is connected to a quarter-wavelength matching microstrip line, and the second end is connected to a specific impedance microstrip line with a width of... w4 = 0.7mm, with a characteristic impedance of 20 ohms, used to match the characteristic impedance of the liquid crystal microstrip line 3; the radius of the first feeding metal cylinder is r1 = 0.7mm, the radius of the first medium filling hole r2 = 1.5mm and uses Rogers TMM4 material; the width of the first primary metal patch and the first parasitic metal patch are both W1 = 26.1mm, lengths are respectively L1 = 16.7mm and L2 =1.4mm, spacing is along the length direction g2 = 1.2mm, the feed center is located on the central axis of the varactor diode array, the feed center is located at the midpoint of the wide side of the main metal patch, and the lengths from the pair of parallel boundaries of the main metal patch are respectively d1 =3.35mm and d2 =13.35mm; the first parasitic metal patch has radii of at both ends being C1 = 1.4mm rounded chamfer; the first varactor diode used in the LCD phase-shift antenna tuning unit is model SMV2020-079LF, and the varactor diode uses an SC-79 package. The specifications for each parameter are as follows: Figure 6 As shown, the specific impedance microstrip line and its characteristic impedance setting can make the equivalent resistance formed by the combination of the liquid crystal microstrip line 3, the first quarter-wavelength matching microstrip line 14, and the second quarter-wavelength matching microstrip line 17 better match the reference microstrip line 25.

[0036] In the power divider network antenna tuning unit, the second back dielectric substrate, dielectric layer 15, second dielectric filling hole 19, and second front-hole dielectric substrate 20 are all Rogers TMM4, employing a hexagonal shape with a side length of 23.4 mm, a dielectric constant of 4.5, and a loss tangent of 0.002. The thickness of the second back dielectric substrate is 0.2 mm, the dielectric layer is 0.19 mm, and the second front-hole dielectric substrate is 1.6 mm. The linewidth of the quarter-wavelength matching microstrip line 17 is... w5 =0.4mm, characteristic impedance is =31 ohms, length 5.46mm, characteristic impedance is =50 ohms reference connection microstrip line width isw6 = 0.2mm, the microstrip linewidth inside the Wilkinson power divider is w7 = 0.1mm, length 9.97mm, characteristic impedance 70.7 ohms; radius of the second feed metal cylinder is r3 = 0.262mm, the radius of the second medium filling hole is r4 =1.5mm and uses Rogers TMM4 material; the width of the second main metal patch and the second parasitic metal patch are both W2 = 26.1mm, lengths are respectively L3 = 16.4mm and L4 = 1.4mm, spacing along the length direction g3 = 1.2mm, the feed center, i.e., the second feed metal cylinder, is located on the central axis of the varactor diode array. The feed center is located at the midpoint of the wide side of the main metal patch, and the lengths from the pair of parallel boundaries of the main metal patch are d3=3.2mm and d4=13.2mm, respectively; the second parasitic metal patch has radii at both ends of... C2 = 1.4mm rounded chamfer; feed center distance from hexagon center is 2mm. The varactor diode used in the power divider feed network antenna tuning unit is model SMV2020-079LF, and the varactor diode uses SC-79 package. The specifications of each parameter are as follows. Figure 7 As shown.

[0037] The dimensions mentioned above are specific dimensions that have been calculated and optimized. If the dimensions change, the performance of the embodiments of the invention will deteriorate.

[0038] Simulation tests were performed on the reconfigurable antenna of this embodiment. A bias voltage of 6V-15V was applied to the varactor diode, and an RF signal within the frequency band was input from the input terminal of the first Wilkinson power divider. Figure 9 This is a simulation result of the antenna return loss in an embodiment of the present invention. From... Figure 10 As can be seen, the antenna has four radiation states within the 3.5GHz-3.75GHz range, with a return loss greater than 12dB, making it suitable for various scenarios such as the Internet of Things and indoor communication.

[0039] Figure 9 This is a 3D radiation pattern simulation result of the antenna under different radiation states at three frequency points in an embodiment of the present invention. As can be seen from the figure, at the three frequency points... f At 3.5GHz, 3.625GHz, and 3.75GHz, the beam radiation direction can be switched at a 45° elevation angle and on a horizontal plane under twelve states (S1-S12) with four radiation modes.

[0040] Figure 11The figure shows the actual simulation results of the peak gain under different radiation states within the antenna operating frequency band in this embodiment of the invention. As can be seen from the figure, at the three frequency points... f At 3.5GHz, 3.625GHz, and 3.75GHz, the maximum actual gain of the antenna exceeds 7dBi across twelve states (S1-S12) for four radiation modes. Figure 12 The figure shows the simulation results of the radiation efficiency under different radiation states within the antenna's operating frequency band in this embodiment of the invention. As can be seen from the figure, at the three frequency points... f At 3.5GHz, 3.625GHz, and 3.75GHz, the antenna's maximum radiation efficiency exceeds 40% under twelve states (S1-S12) of four radiation modes.

[0041] Therefore, it can be seen that the antenna of the present invention can achieve multiple radiation states by controlling the bias voltage on the liquid crystal phase shifting unit and the varactor diode; at the same time, it can achieve reconfigurable radiation pattern and frequency, and full coverage of the horizontal beam at elevation angles of +45° and -45°.

[0042] The foregoing descriptions are preferred embodiments of the present invention. Unless there is a clear contradiction between the preferred embodiments or a prerequisite for a particular preferred embodiment, the preferred embodiments can be arbitrarily combined and used. The embodiments and specific parameters described are only for clearly illustrating the inventor's invention verification process and are not intended to limit the scope of patent protection of the present invention. The scope of patent protection of the present invention shall still be determined by its claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. A pattern-frequency reconfigurable conformal antenna for intelligent robots based on liquid crystal materials, characterized in that... It includes six liquid crystal phase-shift antenna tuning units (1) and a hexagonal power distribution network antenna tuning unit (2) that is electrically and mechanically connected to the six liquid crystal phase-shift antenna tuning units. The six liquid crystal phase-shift antenna tuning units are respectively connected to one side of the power distribution network antenna tuning unit, and two adjacent liquid crystal phase-shift antenna tuning units are also connected by a boundary. The planes where the liquid crystal phase-shift antenna tuning units (1) and the hexagonal power distribution network antenna tuning units (2) are located have an angle at the mechanical connection, and the angle range is 9-13 degrees. The liquid crystal phase-shifting antenna tuning unit includes a first back dielectric substrate, a slotted dielectric substrate (4) and a liquid crystal filling slot (13) disposed on the back dielectric substrate, a first metal dielectric filling hole electrode layer (5) disposed on the side of the slotted dielectric substrate (4) and the liquid crystal filling slot away from the first back dielectric substrate, a first front band hole dielectric substrate (6) disposed on the side of the first metal dielectric filling hole electrode layer (5) away from the first back dielectric substrate, a first main metal patch (7) and a first parasitic metal patch (8) disposed on the side of the first front band hole dielectric substrate (6) away from the first back dielectric substrate, and a plurality of first varactor diodes and a first feed metal cylinder (10) welded in parallel on the first parasitic metal patch; a first dielectric filling hole (12) is provided on the first metal dielectric filling hole electrode layer (5); The power divider feed network antenna tuning unit includes a second back dielectric substrate and a metal circuit layer disposed on the second back dielectric substrate. A microstrip feed network connected to six liquid crystal phase-shifting antenna tuning units is disposed on the metal circuit layer. The microstrip feed network includes six Wilkinson power dividers (16), twelve reference connection microstrip lines (25), and six second quarter-wavelength matching microstrip lines (17) located on the six sides of the antenna tuning unit of the power divider feed network. Each Wilkinson power divider includes one input terminal and two output terminals. The input terminal of the first Wilkinson power divider (161) is the radio frequency signal input terminal, which is directly connected to the input terminals of the second Wilkinson power divider (162) and the third Wilkinson power divider (163) through two reference connection microstrip lines. One output terminal of the second Wilkinson power divider passes through the second front band aperture through the reference connection microstrip line. The dielectric substrate (20), the via dielectric layer and the dielectric substrate layer (15) are connected to the second feed metal cylinder (24), and another output terminal is connected to the input terminal of the fourth Wilkinson power divider; the two output terminals of the third Wilkinson power divider (163) are respectively connected to the input terminals of the fifth Wilkinson power divider and the sixth Wilkinson power divider; the six output terminals of the fourth Wilkinson power divider (164), the fifth Wilkinson power divider (165) and the sixth Wilkinson power divider (166) are respectively connected to the second quarter wavelength matching microstrip line (17) on the six sides of the power divider feed network antenna tuning unit through the reference connection microstrip line (25).

2. The pattern-frequency reconfigurable conformal antenna for intelligent robots as described in claim 1, characterized in that, The liquid crystal phase-shift antenna tuning unit also includes a first quarter-wavelength matching microstrip line (14) disposed between the back dielectric substrate and the slot dielectric substrate (4) and connected to the first end of the liquid crystal microstrip line (3); the second end of the specific impedance microstrip line is connected to the first feed metal cylinder (10) passing through the first dielectric filling hole (12); multiple first varactor diodes (9) are equidistantly welded on a straight line to form a first varactor diode array; the first feed metal cylinder (10) is located on the central axis of the first varactor diode array; and the first quarter-wavelength matching microstrip line (14) serves as the electrical connection end between the liquid crystal phase-shift antenna tuning unit and the power divider feed network antenna tuning unit.

3. The pattern-frequency reconfigurable conformal antenna for intelligent robots as described in claim 1, characterized in that, The first parasitic metal patch (8) is a rounded rectangular metal patch.

4. The pattern-frequency reconfigurable conformal antenna for intelligent robots as described in claim 1, characterized in that, The liquid crystal microstrip line (3) is a planar spiral shape. The first end is located at the outer edge of the planar spiral, and the second end is located at the center of the spiral. The second end is connected to the first feeding metal cylinder (10) through a microstrip line (11) with a specific impedance.

5. The pattern-frequency reconfigurable conformal antenna for intelligent robots as described in claim 1, characterized in that, The power divider network antenna tuning unit further includes a dielectric substrate layer (15) disposed on the metal circuit layer away from the second back dielectric substrate, a second metal dielectric filling hole electrode layer (18) disposed on the dielectric substrate layer away from the back dielectric layer, a second front-band hole dielectric substrate (20) disposed on the second metal dielectric filling hole electrode layer (18) away from the second back dielectric substrate, a second main metal patch (21) and a second parasitic metal patch (22) disposed on the second front-band hole dielectric substrate (20) away from the back dielectric substrate, and is connected in parallel to the two Multiple packaged second varactor diodes (23) are located between metal patches, and a second feed metal cylinder (24) is soldered onto the second main metal patch; a second dielectric filling hole (19) is provided on the second metal dielectric filling hole electrode layer (18), and a reference connection microstrip line (25) is connected to the second feed metal cylinder (24) passing through the second dielectric filling hole (19). Multiple second varactor diodes (23) are soldered at equal intervals on a straight line to form a second varactor diode array, and the second feed metal cylinder (24) is located on the central axis of the second varactor diode array.

6. The pattern-frequency reconfigurable conformal antenna for intelligent robots as described in claim 5, characterized in that, The second parasitic metal patch (22) is a rounded rectangular metal patch.

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