A reconfigurable cone-shaped beam antenna

Abstract

This invention discloses a reconfigurable conical beam antenna. The antenna comprises, from top to bottom, an upper dielectric substrate, an air cavity, an intermediate dielectric substrate, and a lower dielectric substrate stacked sequentially. The purpose of this invention is to utilize three heterogeneous improved inverted-F antennas, whose feed quantity is controllable and can achieve a better conical beam. During antenna operation, circumferential omnidirectionality at a certain angle can be achieved initially. When the target is different, the beam angle can be changed by switching, thereby improving antenna tracking.

Description

Technical Field

[0001] This invention relates to the field of microelectronic antennas, and more particularly to a reconfigurable cone-shaped beam antenna. Background Technology

[0002] Conical beam antennas have wide applications in many civilian and military fields, such as vehicle-mounted satellite communications and missile-borne detection systems, and are one of the key technologies for radio frequency systems in communication, detection, and guidance applications. Currently, there are many challenges in realizing circularly polarized, broadband, large tilt angle, and reconfigurable conical beam antennas, as well as in their pattern synthesis. Array antennas are an important component of conical beam antennas. This paper mainly studies how to achieve broadband, high-gain, low-sidelobe, and beam controllable characteristics when the antenna radiates a conical beam.

[0003] As a crucial front-end component of radio frequency systems, antennas require different characteristics for various applications. Conical beam antennas, possessing omnidirectional characteristics only in the circumferential direction, concentrate their energy within a relatively small elevation angle range, meeting the gain and beam tracking requirements of satellite communications. Compared to phased array antennas, they offer higher cost-effectiveness and are widely used in satellite communications, indoor WLANs, fuses, and missile systems.

[0004] When the antenna is working, for a moving near-ground antenna or a vehicle moving in a certain area, a cone-beam antenna can concentrate its energy within a relatively small elevation angle range, which can meet the requirements of satellite communication for gain and beam tracking, and has a higher cost performance compared to phased arrays.

[0005] Current solutions employ an array of three looped inverted-F antennas to achieve high gain and low sidelobes. However, reconfigurability has not been achieved (K. Wu, S. Liao, W. Che and Q. Xue, "A Compact Planar Conical Beam Array Antenna," 2020 IEEE MTT-S International Wireless Symposium (IWS), Shanghai, China, 2020, pp. 1-3, doi:10.1109 / IWS49314.2020.9359951.). Summary of the Invention

[0006] The purpose of this invention is to utilize three heterogeneous improved inverted-F antennas, whose feed quantity is controllable and can achieve a better conical beam. During antenna operation, circumferential omnidirectionality can be achieved at a certain angle initially. When the target is different, the beam angle can be changed by switching, thereby improving antenna tracking.

[0007] The objective of this invention is achieved by at least one of the following technical solutions.

[0008] A reconfigurable conical beam antenna includes an upper dielectric substrate, an air cavity, an intermediate dielectric substrate, and a lower dielectric substrate stacked sequentially from top to bottom;

[0009] The top of the upper dielectric substrate has three concentric annular metal patches arranged from the inside out. Multiple short-circuit posts are arranged close to the inner ring of the three annular metal patches, which is equivalent to short-circuit walls. Each of the three annular metal patches has a feed metal post, which, together with the corresponding short-circuit post, forms multiple inverted F antennas. The multiple inverted F antennas in the three annular metal patches form three annular array elements from the inside out. The upper surface of the upper dielectric substrate has tuning metal posts corresponding to the inverted F antennas in the three annular array elements, which realizes the function of impedance matching and tuning.

[0010] The ring element can be viewed as a ring structure formed by transforming a traditional rectangular inverted-F planar antenna into an arc-shaped inverted-F planar antenna, and then rotating and replicating it along the central axis by a rotation angle. Since the ring-shaped inverted-F planar antenna evolved from the traditional inverted-F planar antenna, their working principles are similar. Due to the uniform distribution of feed points, the electric field of the antenna is uniformly distributed across the ring aperture. When there are enough feed points, the uniform field across the ring aperture can be approximated as a uniformly distributed magnetic flux ring, thereby exciting a symmetrical conical beam.

[0011] A metal ground is provided on the upper surface of the lower dielectric substrate, a feed network is provided at the bottom of the lower dielectric substrate, and an SMA connector is provided at the center of the bottom of the lower dielectric substrate. The SMA connector is connected to the feed network. A diode switching circuit is provided in the feed network to control whether the outermost ring array element participates in the operation, thereby realizing the reconfigurable beam angle of the antenna.

[0012] The tuning metal pillar and the short-circuit pillar pass through the upper dielectric substrate and the middle dielectric substrate, and the other end is connected to the metal ground; the power supply metal pillar passes through the upper dielectric substrate, the middle dielectric substrate and the lower dielectric substrate, and the other end is connected to the power supply network. The three ring array elements are connected to the power supply network at the bottom of the lower dielectric substrate through the corresponding power supply metal pillars.

[0013] Furthermore, the three ring array elements from the inside out are the first ring array element, the second ring array element, and the third ring array element, respectively.

[0014] The number of feed metal pillars corresponding to the inverted F antennas in the first, second, and third ring array elements are n, n, and 2n, respectively; n is an even number greater than or equal to 4.

[0015] The value of n is determined by simulation and parameter scanning based on the required antenna resonant frequency.

[0016] Furthermore, the tuning metal pillar is located within the annular metal patch, which is used to make the resonant frequencies of the two modes TM0, 1 / 2 and TM2, 1 / 2 of the corresponding annular array element where the inverted F antenna is located as close as possible to the required resonant frequency, thereby generating two resonant points and widening the antenna bandwidth.

[0017] Furthermore, multiple short-circuit posts are set up close to the inner ring of the three annular metal patches to ensure that the inner ring of the three annular metal patches is completely surrounded by short-circuit posts, which is equivalent to a short-circuit wall.

[0018] Furthermore, the power supply network includes a 1-to-n equal power distribution network disposed at the center of the bottom of the lower dielectric substrate and... A sub-feed network that is rotationally symmetric along the central axis.

[0019] Furthermore, the 1-to-n equal power distribution network includes A 1-to-2 function-sharing network, The input ports of the 1-to-2 power splitter network are connected together;

[0020] Each sub-feeder network connects to the output ports of the 1-to-n equal power distribution network, i.e., they are respectively connected to... The output port of the 1-to-2 power splitter network.

[0021] Furthermore, the sub-feed network includes three 1-to-2 power dividers;

[0022] The input of the first power divider is connected to the output port of the 1-to-n equal power divider network. One output of the first power divider is connected to the feed metal post corresponding to the inverted F antenna in the first ring array element, and the other output is connected to the input of the second power divider. One output of the second power divider is connected to the feed metal post corresponding to the inverted F antenna in the second ring array element, and the other output is connected to the input of the third power divider. The two outputs of the third power divider are respectively connected to the feed metal post corresponding to the inverted F antenna in the third ring array element.

[0023] Furthermore, in the sub-feed network, the two output ports of the first power divider are connected in a loop at the first connection point via microstrip lines, and then two ends are branched off from the first connection point. One end is connected to the feed metal post corresponding to the inverted F antenna in the first ring element, and the other output end is connected to the input end of the second power divider. The two output ports of the second power divider are connected in a loop at the second connection point via microstrip lines, and then two ends are branched off from the second connection point. One end is connected to the feed metal post corresponding to the inverted F antenna in the second ring element, and the other output end is connected to the input end of the third power divider. The two output ends of the third power divider are respectively connected to the feed metal post corresponding to the inverted F antenna in a third ring element.

[0024] The structure of the sub-feed network is symmetrical about the line connecting the first connection point and the second connection point.

[0025] Furthermore, the second and third power dividers are connected by a diode switching circuit. By controlling whether voltage is applied, the operation of the third heterogeneous ring is ensured, thereby enabling the reconfigurable beam angle of the antenna.

[0026] Furthermore, in the 1-to-n equal power distribution network of the power supply network... The input ports of each 1-to-2 power splitter network are connected to an SMA connector located at the center of the bottom of the lower media board.

[0027] Compared with the prior art, the advantages of the present invention are as follows:

[0028] 1. By adding short-circuit pins and changing the distance between heterogeneous ring array elements, impedance matching can be better achieved, resulting in a better operating bandwidth.

[0029] 2. By using a pattern synthesis design method and switches, the amplitude and phase of the feed for each heterogeneous array element are adjusted to achieve reconfigurable cone beam angle.

[0030] 3. Its radiation structure and feed point structure are axisymmetric figures along the central axis. When adjusting each output port, simulation can be performed through a part of it, which greatly improves simulation efficiency. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a reconfigurable conical beam antenna according to an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the basic inverted-F loop antenna in an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the radiating portion of a reconfigurable conical beam according to an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the SMA power supply section in an embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of the power supply network in an embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of the sub-feed network in an embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of the RLC series circuit switch in an embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of the structure of the interdigital capacitor in an embodiment of the present invention;

[0039] Figure 9 This is a schematic diagram of the bias circuit in an embodiment of the present invention;

[0040] Figure 10 This is a diagram showing the input reflection coefficients when the switch is closed and open in an embodiment of the present invention.

[0041] Figure 11 This is the actual gain diagram within the frequency band when the switch is off in this embodiment of the invention;

[0042] Figure 12 This is the actual gain diagram within the frequency band when the switch is closed in the embodiment of the present invention;

[0043] Figure 13 This is the normalized radiation pattern of the 5GHz antenna switch being closed and open in an embodiment of the present invention;

[0044] Figure 14 This is a normalized radiation pattern of the antenna switch being closed and open at 5.25 GHz in an embodiment of the present invention.

[0045] Figure 15 This is a normalized radiation pattern of the antenna switch being closed and opened at 5.5 GHz in an embodiment of the present invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the present invention clearer, the specific implementation of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0047] Example:

[0048] A reconfigurable cone-shaped beam antenna, such as Figure 1 As shown, it includes an upper dielectric plate 1, an air cavity 2, an intermediate dielectric plate 3, and a lower dielectric plate 5 stacked sequentially from top to bottom;

[0049] like Figure 2 and Figure 3 As shown, the top of the upper dielectric substrate 1 has three concentric annular metal patches arranged from the inside out. Multiple shorting posts 7 are arranged close to the inner ring of the three annular metal patches, which is equivalent to a short-circuit wall. Each of the three annular metal patches has a feeding metal post 8, which, together with the corresponding shorting post 7, constitutes multiple inverted F antennas. The multiple inverted F antennas in the three annular metal patches constitute three annular array elements from the inside out. The upper surface of the upper dielectric substrate 1 is provided with tuning metal posts 9 corresponding to the inverted F antennas in the three annular array elements to achieve impedance matching and tuning.

[0050] The ring element can be viewed as a ring structure formed by transforming a traditional rectangular inverted-F planar antenna into an arc-shaped inverted-F planar antenna, and then rotating and replicating it along the central axis by a rotation angle. Since the ring-shaped inverted-F planar antenna evolved from the traditional inverted-F planar antenna, their working principles are similar. Due to the uniform distribution of feed points, the electric field of the antenna is uniformly distributed across the ring aperture. When there are enough feed points, the uniform field across the ring aperture can be approximated as a uniformly distributed magnetic flux ring, thereby exciting a symmetrical conical beam.

[0051] like Figure 4 As shown, a metal ground 4 is provided on the upper surface of the lower dielectric substrate 5, a feed network 10 is provided at the bottom of the lower dielectric substrate 5, and an SMA connector 6 is provided at the center of the bottom of the lower dielectric substrate 5. The SMA connector 6 is connected to the feed network 10. A diode switching circuit is provided in the feed network 10 to control whether the outermost ring array element participates in the operation, thereby realizing the reconfigurable beam angle of the antenna.

[0052] Tuning metal pillar 3 and short-circuit pillar 1 pass through the upper dielectric plate 1 and the middle dielectric plate 3, and the other end is connected to the metal ground 4; power supply metal pillar 2 passes through the upper dielectric plate 1, the middle dielectric plate 3 and the lower dielectric plate 5, and the other end is connected to the power supply network 10. The three ring array elements are connected to the power supply network 10 at the bottom of the lower dielectric plate 5 through the corresponding power supply metal pillar 2.

[0053] Furthermore, the three ring array elements from the inside out are the first ring array element, the second ring array element, and the third ring array element, respectively.

[0054] The number of feed metal pillars 2 corresponding to the inverted F antennas in the first ring array element, the second ring array element, and the third ring array element are n, n, and 2n, respectively; n is an even number greater than or equal to 4.

[0055] The value of n is determined by simulation and parameter scanning based on the required antenna resonant frequency.

[0056] In one embodiment, n is set to 4 to enable the antenna to operate at a frequency of 4.6 GHz;

[0057] In one embodiment, n is set to 12 so that the antenna operates at a frequency of 5.25 GHz;

[0058] In one embodiment, n = 8 in order for the antenna to operate at a frequency of 5 GHz.

[0059] Furthermore, the tuning metal pillar 3 is located within the annular metal patch, which is used to make the resonant frequencies of the two modes TM0, 1 / 2 and TM2, 1 / 2 of the corresponding annular array element where the inverted F antenna is located as close as possible to the required resonant frequency, thereby generating two resonant points and widening the antenna bandwidth.

[0060] Furthermore, multiple short-circuit posts 1 are set up close to the inner ring of the three annular metal patches to ensure that the inner ring of the three annular metal patches is all wrapped by the short-circuit posts 1, which is equivalent to a short-circuit wall.

[0061] In one embodiment, n takes the value 8, such as Figure 5 As shown, the power supply network 10 includes a 1-to-8 equal power distribution network located at the bottom center of the lower dielectric plate 5 and four sub-power supply networks that are rotationally symmetrical along the central axis.

[0062] like Figure 5 As shown, the 1-to-8 equal power distribution network includes four 1-to-2 power distribution networks, and the input ports of the four 1-to-2 power distribution networks are connected together.

[0063] The four sub-feed networks are connected to the output ports of the 1-to-8 equal power distribution network, that is, they are connected to the output ports of the four 1-to-2 power distribution networks respectively.

[0064] The sub-feed network includes three 1-to-2 power dividers;

[0065] The input of the first power divider is connected to the output port of the 1-to-8 equal power divider network. One output of the first power divider is connected to the feed metal post corresponding to the inverted F antenna in the first ring array element, and the other output is connected to the input of the second power divider. One output of the second power divider is connected to the feed metal post corresponding to the inverted F antenna in the second ring array element, and the other output is connected to the input of the third power divider. The two outputs of the third power divider are respectively connected to the feed metal post corresponding to the inverted F antenna in the third ring array element.

[0066] like Figure 6 As shown, in one embodiment, in the sub-feed network, the two output ports of the first power divider are connected in a loop at the first connection point via microstrip lines, and then two ends are split from the first connection point. One end is connected to the feed metal post corresponding to the inverted F antenna in the first ring element, and the other output end is connected to the input end of the second power divider. The two output ports of the second power divider are connected in a loop at the second connection point via microstrip lines, and then two ends are split from the second connection point. One end is connected to the feed metal post corresponding to the inverted F antenna in the second ring element, and the other output end is connected to the input end of the third power divider. The two output ends of the third power divider are respectively connected to the feed metal post corresponding to the inverted F antenna in a third ring element.

[0067] The structure of the sub-feed network is symmetrical about the line connecting the first connection point and the second connection point.

[0068] Furthermore, the second and third power dividers are connected by a diode switching circuit. By controlling whether voltage is applied, the operation of the third heterogeneous ring is ensured, thereby enabling the reconfigurable beam angle of the antenna.

[0069] Each output port of the sub-feed network can characterize the corresponding output port of the entire feeder network. Therefore, adjusting the output power ratio and phase difference can be performed on the sub-feed network, saving simulation time. The phase difference between each output port of the feeder network is determined by the transmission line length. In one embodiment, a series resonant RLC circuit is used, such as... Figure 7 To use it as a diode switch, add an interdigital capacitor such as Figure 8 To ensure AC passes while DC is blocked, a bias circuit is added to the simulation, such as... Figure 9 To make it more closely resemble the real object.

[0070] Furthermore, the input ports of the four 1-to-2 power distribution networks in the 1-to-8 equal power distribution network of the power supply network 10 are all connected to the SMA connector 6 located at the bottom center of the lower dielectric plate 5.

[0071] In one embodiment, the upper dielectric substrate 1, the middle dielectric substrate 3, and the lower dielectric substrate 5 have the same radius and material, with a radius of 94 mm, a thickness of 0.762 mm, and are made of Rogers 4350B with a dielectric constant of 3.66. Simulation data testing is performed, such as... Figure 10 As shown, its reflection coefficient S11 has a common bandwidth of 4.95-5.60 and a relative bandwidth of 12.3%, as... Figure 11 As shown, the in-band gain is 10.5 dBi - 11.2 dBi when the switch is off. Figure 12 As shown, the in-band gain is 9.1 dBi–10 dBi after the switch is closed. Beam angle variation is achieved within the operating bandwidth, at 5 GHz, as... Figure 13 As shown, the beam angle in the off state is approximately ±16°; the beam angle in the on state is approximately ±26° at 5.25 GHz. Figure 14 As shown, the beam angle in the off state is approximately ±16°, and the beam angle in the on state is approximately ±28°. At 5.5GHz, as... Figure 15 As shown, the beam angle in the off state is approximately ±14°, and the beam angle in the on state is approximately ±26°.

Claims

1. A reconfigurable conical beam antenna, characterized in that, It includes an upper dielectric plate (1), an air cavity (2), an intermediate dielectric plate (3), and a lower dielectric plate (5) stacked sequentially from top to bottom; The top of the upper dielectric substrate (1) is provided with three concentric annular metal patches from the inside to the outside. Each annular metal patch has multiple short-circuit pillars (7) on its inner side. The multiple short-circuit pillars (7) in each annular metal patch are equivalent to short-circuit walls. Each of the three annular metal patches is provided with multiple feed metal pillars (8). The feed metal pillars (8) in each annular metal patch and the corresponding short-circuit pillars (7) respectively constitute multiple inverted F antennas. The multiple inverted F antennas in the three annular metal patches constitute three annular arrays from the inside to the outside. The upper surface of the upper dielectric substrate (1) is provided with tuning metal pillars (9) corresponding to the inverted F antennas in the three annular arrays to achieve impedance matching and tuning. A metal ground (4) is provided on the upper surface of the lower dielectric substrate (5), a feed network (10) is provided at the bottom of the lower dielectric substrate (5), and an SMA connector (6) is provided at the center of the bottom of the lower dielectric substrate (5). The SMA connector (6) is connected to the feed network (10). A diode switching circuit is provided in the feed network (10) to control whether the outermost ring array participates in the operation, thereby realizing the reconfigurable beam angle of the antenna. The tuning metal post (9) and the short-circuit post (7) pass through the upper dielectric plate (1) and the middle dielectric plate (3), and the other end is connected to the metal ground (4); the power supply metal post (8) passes through the upper dielectric plate (1), the middle dielectric plate (3) and the lower dielectric plate (5), and the other end is connected to the power supply network (10). The three ring arrays are connected to the power supply network (10) at the bottom of the lower dielectric plate (5) through the corresponding power supply metal post (8).

2. The reconfigurable conical beam antenna according to claim 1, characterized in that, The three ring arrays from the inside out are the first ring array, the second ring array, and the third ring array, respectively. The number of feed metal pillars (8) corresponding to the inverted F antennas in the first ring array, the second ring array, and the third ring array are n, n, and 2n, respectively; n is an even number greater than or equal to 4; The value of n is determined by simulation and parameter scanning based on the required antenna resonant frequency.

3. A reconfigurable conical beam antenna according to claim 1, characterized in that, The tuning metal pillar (9) is located inside the ring metal patch and is used to make the resonant frequencies of the two modes TM0, 1 / 2 and TM2, 1 / 2 of the ring array where the corresponding inverted F antenna is located as close as possible to the required resonant frequency, thereby generating two resonant points and thus widening the antenna bandwidth.

4. A reconfigurable conical beam antenna according to claim 1, characterized in that, Multiple short-circuit posts (7) are set up close to the inner ring of the three annular metal patches to ensure that the inner ring of the three annular metal patches is wrapped by the short-circuit posts (7), which is equivalent to a short-circuit wall.

5. A reconfigurable conical beam antenna according to claim 1, characterized in that, The power supply network (10) includes a 1-to-n equal power distribution network located at the bottom center of the lower dielectric plate (5) and A sub-feed network that is rotationally symmetric along the central axis.

6. A reconfigurable conical beam antenna according to claim 5, characterized in that, The 1-to-n equal power distribution network includes A 1-to-2 function-sharing network, The input ports of the 1-to-2 power splitter network are connected together; Each sub-feeder network connects to the output ports of the 1-to-n equal power distribution network, i.e., they are respectively connected to... The output port of the 1-to-2 power splitter network.

7. A reconfigurable conical beam antenna according to claim 6, characterized in that, The sub-feed network includes three 1-to-2 power dividers; The input of the first power divider is connected to the output port of the 1-to-n equal power divider network. One output of the first power divider is connected to the feed metal column corresponding to the inverted F antenna in the first ring array, and the other output is connected to the input of the second power divider. One output of the second power divider is connected to the feed metal column corresponding to the inverted F antenna in the second ring array, and the other output is connected to the input of the third power divider. The two outputs of the third power divider are respectively connected to the feed metal column corresponding to the inverted F antenna in the third ring array.

8. A reconfigurable conical beam antenna according to claim 7, characterized in that, In the sub-feed network, the two output ports of the first power divider are connected to the first connection point via a microstrip line loop. Then, two ends are branched off from the first connection point. One end is connected to the feed metal post corresponding to the inverted F antenna in the first ring array, and the other output end is connected to the input end of the second power divider. The two output ports of the second power divider are connected to the second connection point via a microstrip line loop. Then, two ends are branched off from the second connection point. One end is connected to the feed metal post corresponding to the inverted F antenna in the second ring array, and the other output end is connected to the input end of the third power divider. The two output ends of the third power divider are respectively connected to the feed metal post corresponding to the inverted F antenna in the third ring array. The structure of the sub-feed network is symmetrical about the line connecting the first connection point and the second connection point.

9. A reconfigurable conical beam antenna according to claim 7, characterized in that, The second and third power dividers are connected by a diode switching circuit. By controlling whether voltage is applied, the operation of the third heterogeneous ring is ensured, thereby enabling the antenna beam angle to be reconfigurable.

10. A reconfigurable conical beam antenna according to claim 6, characterized in that, In the power distribution network (10), the 1-to-n equal power distribution network The input ports of each 1-to-2 power splitter network are connected to the SMA connector (6) located at the bottom center of the lower media board (5).

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