A narrow cross-section wideband pattern reconfigurable antenna

Abstract

This invention provides a narrow-section broadband pattern reconfigurable antenna, relating to the field of electromagnetic wave detection UAV communication, comprising: a broadband planar printed omnidirectional antenna, an active metasurface radome, and a dual-band impedance matching network; a gap exists between the broadband planar printed omnidirectional antenna and the active metasurface radome; the active metasurface radome includes multiple metasurface elements loaded with diodes; the state of the active metasurface radome is controlled by controlling the on / off state of the diodes to change the communication mode of the narrow-section broadband pattern; when all diodes are off, the active metasurface radome is in a fully transparent state, and the narrow-section broadband pattern reconfigurable antenna operates in broadband omnidirectional communication mode; when diodes in some areas are on, the active metasurface radome in some areas is in a fully shielded state, and the narrow-section broadband pattern reconfigurable antenna operates in dual-band directional communication mode. This invention can improve anti-interference performance and anti-capture capability.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic wave detection unmanned aerial vehicle (UAV) communication, and in particular to a narrow-section broadband pattern reconfigurable antenna based on an active metasurface radome. Background Technology

[0002] With the development of technology, drones are increasingly being widely used in fields such as radar and communication. They offer advantages such as low cost, strong adaptability, and high mission execution capabilities. However, drone countermeasures are also becoming increasingly sophisticated, significantly increasing the likelihood of drones being jammed and captured. Currently, drone data link communication typically uses narrow-section omnidirectional antennas, which offer advantages such as lightweight, small size, good aerodynamic performance, and excellent omnidirectional radiation performance, but also suffer from weak anti-jamming capabilities. Directional antenna technology, by controlling the antenna's radiation direction, can concentrate energy in its target direction and reduce energy in other directions, thereby achieving anti-jamming and anti-capture purposes and improving the drone's survivability. Narrow-section pattern reconfigurable antennas, while maintaining the advantages of omnidirectional communication, can also achieve omnidirectional / dual-frequency directional communication mode switching. Therefore, directional antenna technology can be used to improve the drone's anti-jamming and anti-capture capabilities, thus attracting widespread attention.

[0003] Pattern reconfigurable antennas have advantages such as low cost, small size, multi-mode adjustability, and strong anti-interference capability. Currently, pattern reconfigurable antennas mainly change the current distribution on the antenna surface and change the radiation mode by means of phased array or by switching devices and power supply network design. However, the above methods have disadvantages such as large size, high cost, and narrow bandwidth, poor anti-interference performance, and weak anti-capture capability, and are not suitable for communication of small and medium-sized military UAVs. Summary of the Invention

[0004] The purpose of this invention is to provide a narrow-section broadband pattern reconfigurable antenna to solve the problems of poor anti-interference performance and weak anti-capture capability in existing UAV communications.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A narrow-section broadband pattern reconfigurable antenna includes: a broadband planar printed omnidirectional antenna, an active metasurface radome surrounding the broadband planar printed omnidirectional antenna, and a dual-frequency impedance matching network loaded at the feed end of the broadband planar printed omnidirectional antenna; a gap exists between the broadband planar printed omnidirectional antenna and the active metasurface radome; the dual-frequency impedance matching network is used to improve the influence of the active metasurface radome on the antenna impedance and extend the bandwidth;

[0007] The active metasurface radome includes multiple metasurface units loaded with diodes;

[0008] The state of the active metasurface radome is controlled by controlling the on / off state of the diodes on the metasurface unit, thereby changing the communication mode of the narrow cross-section broadband radiation pattern; the state of the active metasurface radome includes a fully transparent state and a fully shielded state; the communication mode includes a broadband omnidirectional communication mode and a dual-frequency directional communication mode;

[0009] When all the diodes are off, the active metasurface radome is in a fully transparent state, and the narrow cross-section broadband pattern reconfigurable antenna operates in a broadband omnidirectional communication mode; when some diodes are on, the active metasurface radome in some areas is in a fully shielded state, and the narrow cross-section broadband pattern reconfigurable antenna operates in a dual-frequency directional communication mode.

[0010] Optionally, the broadband planar printed omnidirectional antenna specifically includes: a first dielectric substrate, two pairs of rectangular metal patches disposed on the first dielectric substrate, a coplanar waveguide-type center feed line and a planar balun, and two first metal strips on the back side of the first dielectric substrate.

[0011] Each pair of rectangular metal patches is symmetrically distributed on both sides of the central feed line; the central feed line is coaxially fed and couples energy to the rectangular metal patches on both sides of the central feed line;

[0012] The planar balun connects the central feeder to the coaxial feed port;

[0013] The two first metal strips are respectively connected to the rectangular metal patch on the left and the rectangular metal patch on the right.

[0014] Optionally, the main body of the broadband planar printed omnidirectional antenna is rectangular; the active metasurface antenna radome is a flat elliptical cylinder.

[0015] Optionally, the planar balun is a quarter-wavelength planar balun, and the planar balun is an unbalanced to balanced structure.

[0016] Optionally, the rectangular metal patch is a radial patch, and two pairs of radial patches form a binary linear array.

[0017] Optionally, the relative permittivity of the first dielectric substrate is 4.4, and the loss tangent is 0.025.

[0018] Optionally, the metasurface unit specifically includes: a second dielectric substrate, a square metal patch applied to the second dielectric substrate, four second metal strips, and four diodes;

[0019] The second metal strip is distributed around the square metal patch, and the second metal strip is connected to the square metal patch through the diode; when the diode is off, the metasurface unit is in a transparent state, and when the diode is on, the metasurface unit is in a shielded state.

[0020] Optionally, the relative permittivity of the second dielectric substrate is 3.5 and the loss tangent is 0.04.

[0021] Optionally, when the diode on the metasurface unit is turned off, the insertion loss of the metasurface unit is less than -0.7dB, and the metasurface unit is in a transparent state; when the diode is turned on, the shielding effectiveness of the metasurface unit is less than -10dB, and the metasurface unit is in a shielded state.

[0022] Optionally, the dual-frequency impedance matching network specifically includes: a third dielectric substrate, an L-shaped low-frequency matching network disposed on the third dielectric substrate, and an L-shaped high-frequency matching network; the L-shaped low-frequency matching network and the L-shaped high-frequency matching network are cascaded; the dual-frequency impedance matching network is for the upper and lower frequency bands of the dual-frequency directional communication mode.

[0023] The third dielectric substrate is divided into six regions by setting trenches; wherein the first to fourth regions are distributed on the same vertical plane; the first to fourth regions are located between the fifth and sixth regions; the first region and the second region are connected by a resistor;

[0024] The L-shaped low-frequency matching network includes a first inductor, a second inductor, and a first capacitor; the first inductor and the second inductor are connected in parallel, the first inductor is located between the second region and the fifth region, the second inductor is located between the second region and the sixth region; the first capacitor is located between the second region and the third region.

[0025] The L-shaped high-frequency matching network includes a second capacitor, a third capacitor, and a third inductor; the second capacitor and the third capacitor are connected in parallel; the second capacitor is located between the fourth region and the fifth region; the third capacitor is located between the fourth region and the sixth region; and the third inductor is located between the third region and the fourth region.

[0026] According to specific embodiments provided by the present invention, the following technical effects are disclosed: The present invention provides a narrow-section broadband pattern reconfigurable antenna. By controlling the conduction and cutoff of diodes on an active metasurface radome, the narrow-section broadband pattern reconfigurable antenna can switch between a broadband omnidirectional communication mode and a dual-frequency directional communication mode. Furthermore, a dual-frequency impedance matching network is introduced to match the impedances of low and high frequencies respectively, improving the impedance degradation problem caused by the introduction of the active metasurface radome. The present invention has advantages such as good aerodynamic performance, narrow cross-section, and low cost, which can improve the anti-reconnaissance, anti-interference, and anti-capture capabilities of UAVs, and enhance the security and reliability of communication data links. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the overall architecture of the narrow cross-section broadband pattern reconfigurable antenna provided by the present invention.

[0029] Figure 2 This is a top view of the narrow cross-section broadband pattern reconfigurable antenna provided by the present invention;

[0030] Figure 3 A planar diagram of the broadband planar printed omnidirectional antenna and dual-band impedance matching network provided by the present invention.

[0031] Figure 4 This is a planar view of the metasurface unit of the loaded diode provided by the present invention;

[0032] Figure 5 The transmission coefficient curve of the metasurface unit of the loaded diode provided by the present invention;

[0033] Figure 6 This is a top view of the dual-frequency impedance matching network provided by the present invention;

[0034] Figure 7 The reflection coefficient curve of the L-band of the narrow cross-section broadband pattern reconfigurable antenna provided by the present invention;

[0035] Figure 8 The horizontal plane radiation pattern at 1.4 GHz frequency is shown in the broadband omnidirectional communication mode and the dual-frequency directional communication mode provided by the present invention.

[0036] Figure 9The present invention provides the horizontal plane radiation pattern at 1.8 GHz for the narrow cross-section broadband pattern reconfigurable antenna in broadband omnidirectional communication mode and dual-frequency directional communication mode. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] The purpose of this invention is to provide a narrow-section broadband pattern reconfigurable antenna that can improve anti-interference performance and anti-capture capability.

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] like Figures 1-2 As shown, the present invention provides a narrow cross-section broadband pattern reconfigurable antenna comprising: a broadband planar printed omnidirectional antenna 1, an active metasurface antenna radome 2 surrounding the broadband planar printed omnidirectional antenna 1, and a dual-frequency impedance matching network 3 loaded at the bottom of the broadband planar printed omnidirectional antenna 1, wherein the active metasurface antenna radome 2 is a narrow cross-section active metasurface antenna radome.

[0041] The broadband planar printed omnidirectional antenna 1 has advantages such as low cost and small size, and can provide a good omnidirectional radiation mode in the horizontal plane; the active metasurface radome 2 can change its own electromagnetic characteristics by controlling the on / off state of the diodes 4-4 on it, control the wave transmission area, and thus switch the antenna's radiation mode; the dual-frequency impedance matching network 3 is composed of two cascaded L-shaped networks, which can improve the influence of the active metasurface radome 2 on the antenna impedance, thereby expanding the bandwidth.

[0042] In practical applications, the main body of the broadband planar printed omnidirectional antenna 1 is rectangular; the active metasurface antenna radome 2 with loaded diodes 4-4 is a flat elliptical cylinder, arranged around the broadband planar printed omnidirectional antenna 1, and maintaining a suitable distance from the broadband planar printed omnidirectional antenna 1; the dual-frequency impedance matching network 3 is loaded at the feed end of the broadband planar printed omnidirectional antenna 1.

[0043] As a preferred implementation method, such as Figure 3As shown, the broadband planar printed omnidirectional antenna 1 includes a first dielectric substrate 1-1, two pairs of rectangular metal patches 1-2 disposed on the first dielectric substrate, a coplanar waveguide-type center feed line 1-3 and a planar balun 1-4, and two first metal strips on the back side of the first dielectric substrate 1-1; the rectangular metal patches 1-2 are radiating patches.

[0044] A quarter-wavelength planar balun 1-4 and two pairs of radiating patches distributed on both sides of the center feed line 1-3. The planar balun 1-4, the center feed line 1-3 and the radiating patches are all printed on the same side of the dielectric substrate, and the radiating patches are connected by a first metal strip printed on the other side of the dielectric substrate.

[0045] Furthermore, the first dielectric substrate 1-1 is an FR4 dielectric substrate, and the overall size of the broadband planar printed omnidirectional antenna 1 is 141mm×56.9mm×1.6mm. The broadband planar printed omnidirectional antenna 1 is printed on the FR4 dielectric substrate, and the relative permittivity of the first dielectric substrate 1-1 is 4.4, and the loss tangent is 0.025.

[0046] The broadband planar printed omnidirectional antenna 1 is formed by planar printing of a traditional coaxial collinear antenna, with two pairs of radiating patches forming a binary linear array to improve antenna gain.

[0047] The planar balun 1-4 serves as an unbalanced to balanced structure, improving the problem of uneven current distribution caused by coaxial feeding.

[0048] The dual-frequency impedance matching network 3 is loaded between the broadband planar printed omnidirectional antenna 1 and the center feed line 1-3 to improve the antenna impedance degradation problem.

[0049] As a preferred implementation method, such as Figure 4 As shown, the metasurface unit 4 for loading diodes includes a second dielectric substrate 4-1, a square metal patch 4-2 located at the center of the second dielectric substrate 4-1, four second metal strips 4-3 around the perimeter, and four diodes 4-4 connecting the square metal patch 4-2 and the metal strips. All are printed on the same side of the second dielectric substrate 4-1. The second dielectric substrate 4-1 is made of polyimide (PI), with a relative permittivity of 3.5, a loss tangent of 0.04, and a thickness of 0.2 mm. The second metal strips 4-3 are rectangular metal strips.

[0050] like Figure 5As shown, when diode 4-4 is off, the insertion loss of the metasurface unit is less than -0.7dB, and the metasurface unit is in a transparent state; when diode 4-4 is on, the shielding effectiveness of the metasurface unit is less than -10dB, and the metasurface unit is in a shielded state. By switching the on / off state of diode 4-4, the transmission and reflection of electromagnetic waves can be achieved.

[0051] In a preferred embodiment, the active metasurface radome 2 is composed of 20 × 10 metasurface elements with loaded diodes 4-4 arranged around the broadband planar printed omnidirectional antenna 1. The active metasurface radome 2 has a width of 154.6 mm, a thickness of 30 mm, and a height of 160 mm. When all diodes 4-4 on the radome are off, the active metasurface radome 2 is transparent to electromagnetic waves, and the narrow-section broadband pattern reconfigurable antenna operates in broadband omnidirectional communication mode (i.e., omnidirectional mode in the figure). When three rows of diodes 4-4 on the long side of the radome are off, and the remaining diodes 4-4 are on, electromagnetic waves can only pass through these three rows of elements, and the narrow-section broadband pattern reconfigurable antenna operates in dual-frequency dual-band directional communication mode (i.e., directional mode in the figure). Due to the presence of the active metasurface radome 2, the impedance characteristics of the broadband planar printed omnidirectional antenna 1 are significantly degraded. Therefore, it is necessary to introduce the dual-frequency impedance matching network 3 to simultaneously match the impedance of the broadband omnidirectional communication mode and the dual-frequency directional communication mode.

[0052] As a preferred implementation method, such as Figure 6 As shown, the dual-frequency impedance matching network 3 specifically includes: a third dielectric substrate 3-1, an L-shaped low-frequency matching network and an L-shaped high-frequency matching network disposed on the third dielectric substrate; the L-shaped low-frequency matching network and the L-shaped high-frequency matching network are cascaded; the dual-frequency impedance matching network 3 is for the upper and lower frequency bands of the dual-frequency directional communication mode.

[0053] The third dielectric substrate is divided into 6 regions by setting trenches; wherein the first region to the fourth region are distributed on the same vertical plane; the first region to the fourth region are located between the fifth region and the sixth region; the first region and the second region are connected by a resistor R1 (22Ω).

[0054] The L-shaped low-frequency matching network includes a first inductor L1 (11.6nH), a second inductor L2 (11.6nH), and a first capacitor C1 (8pF); the first inductor and the second inductor are connected in parallel, the first inductor is located between the second region and the fifth region, the second inductor is located between the second region and the sixth region; the first capacitor is located between the second region and the third region.

[0055] The L-shaped high-frequency matching network includes a second capacitor C2 (1pF), a third capacitor C3 (1pF), and a third inductor L3 (0.22nH); the second capacitor and the third capacitor are connected in parallel; the second capacitor is located between the fourth region and the fifth region; the third capacitor is located between the fourth region and the sixth region; and the third inductor is located between the third region and the fourth region.

[0056] After introducing the dual-frequency impedance matching network 3, the impedance characteristics of the narrow cross-section broadband planar printed omnidirectional antenna 1 are improved in both modes.

[0057] Figure 7 The reflection coefficient curve of the L-band of the narrow-section broadband pattern reconfigurable antenna provided for this invention shows that the relative bandwidth of the broadband planar printed omnidirectional antenna 1 is 37.8%. After loading the active metasurface radome 2, the impedance bandwidth does not deteriorate significantly in broadband omnidirectional communication mode, but the impedance bandwidth is significantly reduced in dual-frequency directional communication mode. After matching, the impedance characteristics are improved in both modes. In broadband omnidirectional communication mode, the antenna's relative bandwidth reaches 44.6%; in dual-frequency directional communication mode, the antenna's relative bandwidth at low and high frequencies reaches 9.1% and 15.3%, respectively.

[0058] Figure 8 The images show the horizontal plane radiation patterns at 1.4 GHz in the broadband omnidirectional communication mode and the dual-frequency directional communication mode provided by this invention. Figure 9 The horizontal plane radiation patterns at 1.8 GHz are shown for the narrow cross-section broadband pattern reconfigurable antenna in broadband omnidirectional communication mode and dual-band directional communication mode provided by this invention. It can be seen that in broadband omnidirectional communication mode, the narrow cross-section broadband pattern reconfigurable antenna has a relative bandwidth of 44.6% and a non-circularity of less than 2.5 dBi; in dual-band directional communication mode, the upper and lower frequency bands of the narrow cross-section broadband pattern reconfigurable antenna are 1.4 GHz and 1.8 GHz, respectively, with relative bandwidths of 9.1% and 15.3%, and a maximum gain of 5.2 dBi.

[0059] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0060] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A narrow cross-section wideband pattern reconfigurable antenna, characterized in that, include: A broadband planar printed omnidirectional antenna, an active metasurface radome surrounding the broadband planar printed omnidirectional antenna, and a dual-frequency impedance matching network loaded at the feed end of the broadband planar printed omnidirectional antenna; There is a gap between the broadband planar printed omnidirectional antenna and the active metasurface radome; the dual-band impedance matching network is used to improve the influence of the active metasurface radome on the antenna impedance and expand the bandwidth; the main body of the broadband planar printed omnidirectional antenna is rectangular; the active metasurface radome is a flat elliptical cylinder; the active metasurface radome is composed of 20×10 metasurface units of the loaded diodes arranged around the broadband planar printed omnidirectional antenna; the active metasurface radome has a width of 154.6 mm, a thickness of 30 mm, and a height of 160 mm; the dual-band impedance matching network specifically includes: a third dielectric substrate, an L-shaped low-frequency matching network disposed on the third dielectric substrate, and an L-shaped high-frequency matching network; the L-shaped low-frequency matching network and the L-shaped high-frequency matching network are cascaded; the dual-band impedance matching network is for the upper and lower frequency bands of the dual-band directional communication mode; The third dielectric substrate is divided into six regions by setting trenches; wherein the first to fourth regions are distributed on the same vertical plane; the first to fourth regions are located between the fifth and sixth regions; the first region and the second region are connected by a resistor; The L-shaped low-frequency matching network includes a first inductor, a second inductor, and a first capacitor; the first inductor and the second inductor are connected in parallel, the first inductor is located between the second region and the fifth region, the second inductor is located between the second region and the sixth region; the first capacitor is located between the second region and the third region. The L-shaped high-frequency matching network includes a second capacitor, a third capacitor, and a third inductor; the second capacitor and the third capacitor are connected in parallel; the second capacitor is located between the fourth region and the fifth region; the third capacitor is located between the fourth region and the sixth region; the third inductor is located between the third region and the fourth region. The active metasurface radome includes multiple metasurface units loaded with diodes; each metasurface unit specifically includes: a second dielectric substrate, a square metal patch applied to the second dielectric substrate, four second metal strips, and four diodes; The second metal strip is distributed around the square metal patch, and the second metal strip is connected to the square metal patch through the diode; when the diode is off, the metasurface unit is in a wave-transparent state, and when the diode is on, the metasurface unit is in a shielded state. The second dielectric substrate is made of polyimide, with a relative permittivity of 3.5, a loss tangent of 0.04, and a thickness of 0.2 mm. When the diode on the metasurface unit is turned off, the insertion loss of the metasurface unit is less than -0.7dB, and the metasurface unit is in a transparent state; when the diode is turned on, the shielding effectiveness of the metasurface unit is less than -10dB, and the metasurface unit is in a shielded state. The state of the active metasurface radome is controlled by controlling the on / off state of the diodes on the metasurface unit, thereby changing the communication mode of the narrow cross-section broadband radiation pattern; the state of the active metasurface radome includes a fully transparent state and a fully shielded state; the communication mode includes a broadband omnidirectional communication mode and a dual-frequency directional communication mode; When all the diodes are off, the active metasurface radome is in a fully transparent state, and the narrow cross-section broadband pattern reconfigurable antenna operates in a broadband omnidirectional communication mode; when some diodes are on, the active metasurface radome in some areas is in a fully shielded state, and the narrow cross-section broadband pattern reconfigurable antenna operates in a dual-frequency directional communication mode. In broadband omnidirectional communication mode, the narrow cross-section broadband pattern reconfigurable antenna has a relative bandwidth of 44.6% and a non-circularity of less than 2.5 dBi. In dual-band directional communication mode, the upper and lower frequency bands of the narrow cross-section broadband pattern reconfigurable antenna are 1.4 GHz and 1.8 GHz, respectively, with relative bandwidths of 9.1% and 15.3%, respectively, and a maximum gain of 5.2 dBi.

2. The narrow-section broadband pattern reconfigurable antenna according to claim 1, characterized in that, The broadband planar printed omnidirectional antenna specifically includes: a first dielectric substrate, two pairs of rectangular metal patches disposed on the first dielectric substrate, a coplanar waveguide-type center feed line and a planar balun, and two first metal strips on the back side of the first dielectric substrate. Each pair of rectangular metal patches is symmetrically distributed on both sides of the central feed line; the central feed line is coaxially fed and couples energy to the rectangular metal patches on both sides of the central feed line; The planar balun connects the central feeder to the coaxial feed port; The two first metal strips are respectively connected to the rectangular metal patch on the left and the rectangular metal patch on the right.

3. The narrow-section broadband pattern reconfigurable antenna according to claim 2, characterized in that, The planar balun is a quarter-wavelength planar balun, and the planar balun is an unbalanced to balanced structure.

4. The narrow-section broadband pattern reconfigurable antenna according to claim 2, characterized in that, The rectangular metal patch is a radial patch, and two pairs of the radial patches form a binary linear array.

5. The narrow-section broadband pattern reconfigurable antenna according to claim 2, characterized in that, The first dielectric substrate has a relative permittivity of 4.4 and a loss tangent of 0.

025.

6. The narrow-section broadband pattern reconfigurable antenna according to claim 1, characterized in that, The second dielectric substrate has a relative permittivity of 3.5 and a loss tangent of 0.04.

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