A novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array

Abstract

The present application discloses a novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array, comprising a planar full-duplex antenna radiating plate, a first substrate, an orthogonal integrated converter, a composite metal support base, a second substrate, and a feeding network stacked in sequence; the outer diameter of the first substrate is smaller than the outer diameter of the second substrate, and the planar full-duplex antenna radiating plate is attached to the surface of the first substrate for arrangement; the composite metal support base is recessed inwardly on one side facing the first substrate to form a cavity; the bottom end of the orthogonal integrated converter is fixed to the bottom surface of the cavity, and the top surface of the orthogonal integrated converter supports the first substrate; both the first substrate and the second substrate are insulating substrates; the second substrate is attached to the bottom surface of the composite metal support base, and the feeding network is attached to the bottom surface of the second substrate for arrangement. The above antenna array realizes an integrated design and has the characteristics of compact structure; and the transmitting and receiving ports have high isolation and small axial ratio, and high working stability.

Description

Technical Field

[0001] The present application relates to the technical field of wireless communication equipment, and in particular to a novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array. Background Art

[0002] Increasing spectrum efficiency and expanding system capacity are eternal pursuits in the wireless communications field. However, traditional system capacity expansion technologies have reached their limits. Simultaneous Transmit and Receive (STAR), also known as In-Band Full-Duplex (IBFD), is attracting significant attention as a promising approach. Because full-duplex antenna technology enables wireless devices to transmit and receive signals simultaneously on the same frequency, it has the potential to further double spectrum efficiency and system capacity compared to current half-duplex communications.

[0003] A key challenge in designing full-duplex antenna systems is the need to eliminate self-interference (SI) signals in both the transmit and receive links. The required level of self-interference cancellation (SIC) varies by application, but typically exceeds 110 dB. To achieve high levels of SIC, various SIC techniques are employed in the antenna, analog, and digital domains. Achieving high levels of SIC in the antenna domain reduces the burden of suppressing self-interference in other domains and reduces the complexity of full-duplex antenna systems.

[0004] In the antenna field, in addition to high isolation between the transmit and receive antennas, they are often required to have the same polarization (collinear polarization (Co-LP) or co-circular polarization (Co-CP)) and similar radiation patterns, making antenna design even more challenging. To achieve this goal, a variety of self-interference cancellation techniques have been developed in the antenna field, including near-field cancellation, mode orthogonality, common-mode (CM) and differential-mode (DM) cancellation, loading decoupling structures or circuits, and dual-polarization sequential rotation arrays.

[0005] Quadrifilar helical antennas are commonly used to design broadband, co-circularly polarized, full-duplex antennas with normal radiation. Leveraging the geometric symmetry of quadrifilar helical antennas, two of the balun feed arms serve as transmitting antennas, while the other two orthogonal arms serve as receiving antennas. This theoretically enables infinitely good isolation between the transmitting and receiving antennas. However, conventional quadrifilar helical antennas radiate based on a traveling wave structure, which is frequency-independent. To achieve better circular polarization performance (low axial ratio (AR)), resistors or helical wires are typically connected to the ends to reduce the impact of parasitic arm end reflections, or absorbing materials are used as backing on the back. However, these methods result in a decrease in antenna gain and radiation efficiency. To improve normal gain and antenna efficiency, some researchers have proposed adding lens loading to the radiating side of the helical antenna and metal cavities to the back. However, these methods significantly increase the size of the antenna structure. Furthermore, the use of commercial off-the-shelf (COTS) components to construct the feed network and the use of multiple coaxial cables to connect the helical antennas results in a complex and uncompact system structure, high cost, unstable performance, and ultimately only limited isolation between the transmitting and receiving antennas.

[0006] Therefore, the simultaneous transmitting and receiving antenna in the prior art method has the problem of poor working performance stability. Summary of the Invention

[0007] The embodiment of the present application provides a novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array, which aims to solve the problems of poor working stability, low gain and efficiency of simultaneous transmitting and receiving antennas in the existing technical methods.

[0008] The embodiment of the present application provides a novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array, which includes a planar full-duplex antenna radiation plate, a first substrate, an orthogonal integrated converter, a composite metal support base, a second substrate and a feed network stacked in sequence;

[0009] The outer diameter of the first substrate is smaller than the outer diameter of the second substrate, and the planar full-duplex antenna radiation plate is attached to the surface of the first substrate for installation; the side of the composite metal support seat facing the first substrate is recessed inward to form a cavity; the bottom end of the orthogonal integrated converter is fixed to the bottom surface of the cavity, and the top surface of the orthogonal integrated converter supports the first substrate; the first substrate and the second substrate are both insulating substrates;

[0010] The second substrate is attached to the bottom surface of the composite metal support base, and the feeding network is attached to the bottom surface of the second substrate for installation;

[0011] The planar full-duplex antenna radiation plate includes a connecting piece and an outer ring, wherein the connecting piece is arranged at the center of the outer ring, and a plurality of four-arm spiral units are arranged between the connecting piece and the outer ring and arranged around the center of the outer ring; each of the four-arm spiral units is connected to the connecting piece and the outer ring; and the top surface of each of the orthogonal integrated converters is connected to a group of the four-arm spiral units respectively.

[0012] Two adjacent microstrip lines in two adjacent groups of four-arm spiral units are coupled via a coupling cross-finger structure.

[0013] The novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array, wherein the four-arm spiral unit includes four spiral microstrip lines spiraling around the same center; wherein the third spiral microstrip line is connected to the outer ring, the end of the first spiral microstrip line is coupled to the microstrip line in an adjacent group of four-arm spiral units, and the second spiral microstrip line is connected to the connecting piece and the end thereof is coupled to the microstrip line in another adjacent group of four-arm spiral units;

[0014] The fourth spiral microstrip line and the first spiral microstrip line are combined into a receiving unit, and the second spiral microstrip line and the third spiral microstrip line are combined into a transmitting unit.

[0015] The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array, wherein four groups of the four-arm spiral units are provided between the connecting piece and the outer ring.

[0016] In the novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array, the spiral microstrip lines in each of the four-arm spiral units spiral outward in a counterclockwise direction.

[0017] The novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array, wherein the coupled cross-finger structure includes a microstrip line in a four-arm spiral unit for coupling, and a plurality of racks are provided at the end of the microstrip line, and the racks at the end of the microstrip line are embedded in the gap between the racks of another microstrip line.

[0018] The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array is provided with an outwardly protruding flange at the outer edge of the outer ring, and the flange is arranged at the central axis of the two adjacent groups of four-arm spiral units.

[0019] The novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array is provided with a plurality of wing ribs between the bottom surface and the inner side surface of the cavity; the end surfaces of the wing ribs are perpendicular to the bottom surface of the cavity, and the wing ribs are evenly arranged around the center of the bottom surface of the cavity.

[0020] The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array, wherein the height of the orthogonal integrated converter is greater than the depth of the cavity.

[0021] The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array, wherein the orthogonal integrated converter comprises a first plate and a second plate in an orthogonal combination; the first plate and the second plate are both insulating plates;

[0022] A first slit is provided below the central axis of the first plate, and a second slit is provided above the central axis of the second plate;

[0023] The front surface of the first plate and the front surface of the second plate are both provided with a Γ-shaped microstrip line, and the lateral feeding ends of the Γ-shaped microstrip line are both bent downward; the back surface of the first plate and the back surface of the second plate are both covered with two ground metal plates with a gap; the gap between the ground metal plates is set at the central axis of the plate; the bottom ends of the ground metal plates are connected to the bottom surface of the cavity;

[0024] The four microstrip lines in the four-arm spiral unit are respectively connected to a ground metal plate.

[0025] The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array, wherein the feeding network includes two broadband 1-to-4 power splitter feeding sub-networks, each of which is composed of three two-stage Wilkinson power splitters.

[0026] The embodiment of the present application provides a novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array, comprising a planar full-duplex antenna radiating plate, a first substrate, an orthogonal integrated converter, a composite metal support base, a second substrate and a feeding network stacked in sequence; the outer diameter of the first substrate is smaller than the outer diameter of the second substrate, and the planar full-duplex antenna radiating plate is attached to the surface of the first substrate for arrangement; the composite metal support base is recessed inwardly on one side facing the first substrate to form a cavity; the bottom end of the orthogonal integrated converter is fixed to the bottom surface of the cavity, and the top surface of the orthogonal integrated converter supports the first substrate; both the first substrate and the second substrate are insulating substrates; the second substrate is attached to the bottom surface of the composite metal support base, and the feeding network is attached to the bottom surface of the second substrate for arrangement. The above antenna array realizes an integrated design and has the characteristics of compact structure; and there is high isolation and a small axial ratio between the transmitting and receiving ports, and high working stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0028] Figure 1 An exploded diagram of the novel broadband single-station co-circularly polarized, co-frequency, simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0029] Figure 2 This is a top structural diagram of the novel broadband single-station co-circularly polarized, co-frequency, simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0030] Figure 3 Provided in the embodiments of this application Figure 2 Local structure diagram of area A in the middle;

[0031] Figure 4 Provided in the embodiments of this application Figure 2 Local structural diagram of the middle B area;

[0032] Figure 5 A partial structural diagram of a novel broadband single-station co-circularly polarized, co-frequency, simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0033] Figure 6 Another partial structural diagram of the novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0034] Figure 7 Another partial structural diagram of the novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0035] Figure 8 Schematic diagram of the processing process of the planar full-duplex antenna radiator in the novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0036] Figure 9 A three-dimensional structural comparison diagram of the novel broadband single-station co-circularly polarized, co-frequency, simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0037] Figure 10 Schematic diagram of the effect of the new broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0038] Figure 11 Schematic diagram of the effect of the new broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0039] Figure 12 Schematic diagram of the effect of the new broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0040] Figure 13 Schematic diagram of the effect of the new broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0041] Figure 14 Schematic diagram of the effect of the new broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0042] Figure 15 Schematic diagram of the effect of the new broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0043] Figure 16 Schematic diagram of the effect of the new broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0044] Figure 17 Schematic diagram of the effect of the new broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0045] Figure 18 Schematic diagram of the effect of the new broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0046] Figure 19 Schematic diagram of the effect of the new broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application.

[0047] Figure numbers: 1. Planar full-duplex antenna radiation plate; 2. First substrate; 3. Orthogonal integrated converter; 4. Composite metal support base; 5. Second substrate; 6. Feed network; 41. Cavity; 11. Connecting plate; 12. Outer ring; 13. Four-arm spiral unit; 14. Coupled cross-finger structure; 131. First spiral microstrip line; 132. Second spiral microstrip line; 133. Third spiral microstrip line; 134. Fourth spiral microstrip line; 141. Rack; 121. Flange; 42. Wing rib; 31. First plate; 32. Second plate; 311. First gap; 312. Second gap; 33. Γ-shaped microstrip line; 34. Ground metal plate; 61. Transmitting port; 62. Receiving port; 63. Two-stage Wilkinson power divider. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0049] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0050] It should also be understood that the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0051] It should be further understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0052] See also Figure 1 As shown in the figure, the embodiment of the present application discloses a novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array, comprising a planar full-duplex antenna radiation plate 1, a first substrate 2, an orthogonal integrated converter 3, a composite metal support base 4, a second substrate 5 and a feeding network 6 stacked in sequence; the outer diameter of the first substrate 2 is smaller than the outer diameter of the second substrate 5, and the planar full-duplex antenna radiation plate 1 is attached to the surface of the first substrate 2 for arrangement; the composite metal support base 4 is recessed inward on one side facing the first substrate 2 to form a cavity 41; the bottom end of the orthogonal integrated converter 3 is fixed to the bottom surface of the cavity 41, and the top surface of the orthogonal integrated converter 3 supports the first substrate 2; the first substrate 2 and the second substrate 5 are both insulating substrates; the second substrate 5 is attached to the bottom surface of the composite metal support base 4, and the feeding network 6 is attached to the bottom surface of the second substrate 5 for arrangement.

[0053] The specific structure of the novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array disclosed in this application is as follows: Figure 1 As shown, the antenna array consists of a planar full-duplex antenna radiation plate 1, an orthogonal integrated converter 3 (orthogonal integrated balun), a composite metal support base 4 and a feeding network 6.

[0054] Furthermore, the first substrate 2, the second substrate 5, and the composite metal support base 4 may all be circular. In a specific embodiment, the specific design values ​​of each dimension are shown in Table 1:

[0055] Table 1 (dimensions in mm)

[0056] <![CDATA[R g ]]> H <![CDATA[R1]]> <![CDATA[R2]]> <![CDATA[R3]]> <![CDATA[l1]]> <![CDATA[l2]]> <![CDATA[g1]]> 125 29 86 17 79.5 6.9 39 0.81 <![CDATA[g2]]> <![CDATA[g3]]> <![CDATA[w1]]> <![CDATA[w2]]> <![CDATA[w3]]> <![CDATA[w4]]> <![CDATA[h r1 ]]> <![CDATA[h r2 ]]> 0.81 2.13 0.45 3 2.5 6.5 13 5 <![CDATA[t r1 ]]> <![CDATA[t r2 ]]> <![CDATA[l r1 ]]> 2 3 18

[0057] Specifically, such as Figure 2 and Figure 4 As shown, the planar full-duplex antenna radiation plate 1 includes a connecting piece 11 and an outer ring 12, the connecting piece 11 is arranged at the center of the outer ring 12, and a plurality of groups of four-arm spiral units 13 are arranged between the connecting piece 11 and the outer ring 12 and arranged around the periphery of the center of the outer ring 12; each of the four-arm spiral units 13 is connected to the connecting piece 11 and the outer ring 12; the top surface of each of the orthogonal integrated converters 3 is respectively connected to a group of the four-arm spiral units 13; the two adjacent microstrip lines in the two adjacent groups of the four-arm spiral units 13 are coupled through a coupling cross-finger structure 14.

[0058] The planar full-duplex antenna radiation plate 1 includes a connecting piece 11, an outer ring 12, and multiple groups of four-arm spiral units 13. In the specific embodiment of the present application, four four-arm spiral units 13 are arranged to form a 2×2 four-arm spiral array, and each four-arm spiral unit 13 is an array unit formed by combining four spiral microstrip lines. In order to improve the circularly polarized radiation performance of the array, the design introduces four compact coupling structures at the ends of the microstrip lines in adjacent four-arm spiral units 13, and adds a circular connecting piece 11 and an outer ring 12 at the center and periphery of the array respectively.

[0059] In a more specific embodiment, the four-arm spiral unit 13 includes four spiral microstrip lines spiraling around the same center of a circle; wherein the third spiral microstrip line 133 is connected to the outer ring 12, the end of the first spiral microstrip line 131 is coupled with the microstrip line in an adjacent group of four-arm spiral units 13, the second spiral microstrip line 132 is connected to the connecting piece 11 and the end thereof is coupled with the microstrip line in another adjacent group of four-arm spiral units 13; the fourth spiral microstrip line 134 is combined with the first spiral microstrip line 131 to form a receiving unit, and the second spiral microstrip line 132 is combined with the third spiral microstrip line 133 to form a transmitting unit. Four groups of the four-arm spiral units 13 are provided between the connecting piece 11 and the outer ring 12. Specifically, the spiral microstrip lines in each of the four-arm spiral units 13 spiral outward in a counterclockwise direction.

[0060] like Figure 2As shown, to achieve infinitely good isolation between the transmit and receive ports, two spiral microstrip lines (spiral arms) in a quadrilateral helical element 13 serve as transmitting elements, while two other spiral microstrip lines (spiral arms) placed orthogonally thereto serve as receiving elements. These four quadrilateral helical elements 13 are fed with equal amplitude and phase, forming a 2×2 array. The antenna's radiation aperture is printed on a first substrate 2, which has a relative dielectric constant (εr) of 3.66 and a dielectric loss tangent (tanδ) of 0.0037. The first substrate 2 is a circular substrate (made of Rogers 4350B) with a radius of R1 and a thickness of h1. Similarly, the second substrate 5 can be set to a circular substrate made of Rogers 4350B with a thickness of h2.

[0061] In order to study the co-circular polarization radiation mechanism of the full-duplex antenna, the processing process of the planar full-duplex antenna radiation plate 1 is as follows: Figure 8 Specifically comprising: Step 1, four four-arm spiral units 13 form a 2×2 array, corresponding to Figure 8 Figure (a); Step 2, introduce a compact coupling structure, corresponding to Figure 8 Figure (b) Step 3. Add outer ring 12, corresponding to Figure 8 Figure (c); Step 4, introduce a circular connecting piece 11 in the center of the array, corresponding to Figure 8 Middle (d) figure.

[0062] The antennas of all stages are located at a radius of π×R g 2 mm, and a circular ground plane with a height of H mm, such as Figure 1 As shown, H is the height of the planar full-duplex antenna radiation plate from the bottom of the cavity, R g That is, the bottom radius of the cavity, and the ground plane is the bottom surface of the cavity 41. Since the antenna structure has rotational symmetry, the transmitting port 61 and the receiving port 62 have the same circularly polarized radiation performance (in the embodiment of the present application, the transmitting port 61 and the receiving port 62 antennas are both right-handed circularly polarized, that is, the spiral microstrip lines are all spiraled outward counterclockwise). Therefore, in this application, only the simulation results when the transmitting port 61 is excited are analyzed and discussed. Due to the ideal differential feeding between the two pairs of orthogonal arms, infinitely good isolation of the transmitting and receiving ports can be achieved in theory. Therefore, this application will not show the isolation results of the transmitting and receiving ports. Step 1: Figure 8 Figure (a) shows a 2×2 array consisting of four four-arm helical units 13, each of which has 1.5 turns. The reflection coefficient of the array is shown in Figure 10As shown in Figure (a), the reflection coefficient is lower than -5dB in the frequency band of 2-4GHz, which indicates that the impedance matching of the quadrilateral helix is ​​not ideal in this frequency band. In addition, as expected, step 1 cannot achieve satisfactory normal circular polarization radiation. Figure 10 As shown in Figure (b), the antenna structure in step 1 was tested in the frequency range of 2.6-3.8 GHz, and the normal axial ratio exceeded 15 dB. This deterioration of the axial ratio is mainly caused by the reflection of the residual current at the end of the spiral arm. Therefore, in order to improve the axial ratio of the antenna, the reflected current at the end of the spiral arm must be reduced to a minimum. In order to be clearer in the subsequent description, the spiral arms are divided into four groups in the specific embodiment of the present application, namely the first spiral microstrip line 131 (also known as arm-1), the second spiral microstrip line 132 (also known as arm-2), the third spiral microstrip line 133 (also known as arm-3), and the fourth spiral microstrip line 134 (also known as arm-4), as shown in FIG. Figure 8 As shown in Figure (a).

[0063] Specifically, such as Figure 3 As shown, the coupled interdigital structure 14 includes a plurality of racks 141 provided at the ends of the microstrip lines for coupling in the four-arm spiral unit 13 , and the racks 141 at the ends of the microstrip lines are embedded in the gaps between the racks 141 of another microstrip line.

[0064] Step 2: To reduce the reflection at the ends of Arm-1 and Arm-2, Step 2 introduces four compact coupling structures (TCIS) at the ends of the arms, such as Figure 8 As shown in (b) in the figure, the residual current is connected to each other through arm-1 and arm-2. This connection makes the originally discontinuous current become continuous, thus forming a traveling wave. The specific test results are shown in Figure 11 As shown, Figure 11 is the current distribution of two adjacent four-arm spiral units 13 at different phase angles at 3.2 GHz, Figure 11 The phase angle corresponding to Figure (a) is 0°; Figure 11 The phase angle corresponding to Figure (b) is 90°.

[0065] Step 3: In order to further improve the axial ratio of the antenna, step 3 introduces an outer ring 12, such as Figure 8 As shown in Figure (c). This outer ring 12 connects the end of arm-3 of each spiral unit. In this way, the residual current at the end of the arm flows into the outer ring 12 and generates a traveling wave on it, thereby reducing the current reflection at the end of arm-3. The specific test results are shown in Figure 1. Figure 12 As shown, Figure 12 is the current distribution of different phase angles on the outer ring 12 at 3.2GHz, Figure 12 The phase angle corresponding to Figure (a) is 0°; Figure 12 The phase angle corresponding to Figure (b) is 90°.

[0066] Step 4: In order to broaden the axial ratio bandwidth of the antenna, a circular connecting piece 11 is introduced in the center of the array in step 4, as shown in FIG. Figure 8 As shown in Figure (d) in the figure, the circular connecting piece 11 connects the end of the arm-2 of each spiral unit. Figure 13 The current distribution on a single spiral is shown with and without the circular connecting piece 11. Figure 13 Figure (a) shows the test results without the circular connecting piece 11; Figure 13 Figure (b) shows the test results with circular connector 11. It can be seen that by introducing circular connector 11, part of the current on arm-2 is diverted to circular connector 11, effectively reducing the current along arm-2. Furthermore, the coupling current from arm-2 to arm-4 is greatly reduced, thereby weakening the reflected current at the end of arm-4. Figure 13 As shown. Since the currents at the ends of arm-1, arm-2, and arm-3 form traveling waves, the current at the end of arm-4 is also attenuated, which effectively reduces the end reflection current on each arm of the four four-arm spiral units 13, resulting in a significant improvement in the antenna axial ratio in step 4. This improvement widens the 3dB axial ratio bandwidth of the antenna to 2.75-3.6GHz. In addition, in the frequency band of 2.3-4GHz, the reflection coefficient of step 4 remains below -10dB, as shown in FIG. Figure 10 As shown in Figure (a).

[0067] In a more specific embodiment, Figure 1 and Figure 9 As shown, the outer edge of the outer ring 12 is further provided with a flange 121 protruding outward, and the flange 121 is arranged at the central axis of two adjacent groups of the four-arm spiral units 13.

[0068] In order to further improve the transmitting and receiving effects of the antenna, a flange 121 can be provided at the outer edge of the outer ring 12, and the flange 121 is provided at the central axis of two adjacent groups of four-arm helical units 13. The specific structure is as follows: Figure 2 and Figure 8 shown.

[0069] like Figure 1 As shown, the height of the orthogonal integrated converter 3 is greater than the depth of the cavity 41. Specifically, as Figure 5 As shown, a plurality of wing ribs 42 are provided between the bottom surface and the inner side surface of the cavity 41; the end surfaces of the wing ribs 42 are perpendicular to the bottom surface of the cavity 41, and the wing ribs 42 are evenly arranged around the center of the bottom surface of the cavity 41.

[0070] In order to improve the structural strength of the cavity 41 , a plurality of ribs 42 may be provided between the bottom surface and the inner side surface of the cavity 41 .

[0071] In a more specific embodiment, Figure 6 As shown, the orthogonal integrated converter 3 includes a first plate 31 and a second plate 32 for orthogonal combination; both the first plate 31 and the second plate 32 are insulating plates; a first slot 311 is provided below the central axis of the first plate 31, and a second slot 312 is provided above the central axis of the second plate 32; a Γ-shaped microstrip line 33 is provided on the front of the first plate 31 and the front of the second plate 32, with the lateral feed ends of the Γ-shaped microstrip line 33 bent downward; the back of the first plate 31 and the back of the second plate 32 are covered with two ground metal plates 34 with gaps; the gap between the ground metal plates 34 is provided at the central axis of the plates; the bottom ends of the ground metal plates 34 are connected to the bottom surface of the cavity 41; and the four microstrip lines in the four-arm spiral unit 13 are each connected to a ground metal plate 34. TX stands for transmit and RX stands for receive.

[0072] The orthogonal integrated converter 3 is also an orthogonal integrated balun (balanced-unbalanced converter, Integrated Balun). In order to achieve orthogonal differential feeding of the four-arm spiral unit 13 and ensure good matching with the 50Ω port impedance, the present application designs two broadband integrated baluns to form an orthogonal integrated balun, which are respectively represented as Balun A (corresponding to the first plate 31) and Balun B (corresponding to the second plate 32). Figure 6 As shown in Figure 1, each balun consists of a Γ-shaped microstrip line 33 on the front and a balun ground with a gap on the back. Both baluns are built on a Rogers 4350B substrate in a vertical direction and are placed orthogonally to each other. The Γ-shaped microstrip line 33 is divided into a microstrip line and an open-circuit branch, both of which are printed on the front of the flat plate (dielectric substrate), as shown in Figure 1. Figure 6 As shown in Figure (a) in the figure. To avoid overlap, the Γ-shaped microstrip line 33 of one of the two baluns is bent at the feeding point. The slot line divides the balun floor into two parts, as shown in Figure (a). Figure 6 As shown in Figure (a), these two parts are used to connect the four-arm spiral to the ground plane, providing equal-amplitude and opposite-direction currents to the spiral units, thereby achieving effective differential feeding. It is worth noting that the widths of the first slot 311 and the second slot 312 can be different. The thickness of the balun substrate is h3 = 0.762 mm, and the slot width reaches G1 = 2 mm. This improvement ensures that there is no direct contact between the microstrip feed point of one balun and the substrate of the other balun, thereby reducing the feed phase deviation.

[0073] In a specific embodiment, the dimensions of the orthogonal integrated converter 3 are shown in Table 2:

[0074] Table 2 (dimensions in mm)

[0075] <![CDATA[L2]]> <![CDATA[L3]]> <![CDATA[L4]]> <![CDATA[L5]]> <![CDATA[L6]]> <![CDATA[L7]]> <![CDATA[L8]]> <![CDATA[L9 <!-- 7 -->]]> 4 11 5.4 12 2.262 2 1.5 12 <![CDATA[L 10 ]]> <![CDATA[W2]]> <![CDATA[W3]]> <![CDATA[W4]]> <![CDATA[W5]]> <![CDATA[W6]]> <![CDATA[G1]]> <![CDATA[G2]]> 18.4 0.6 1.1 1.68 0.5 3 2 0.762 H 29

[0076] In a more specific embodiment, Figure 7 As shown, the feed network 6 includes two broadband 1-to-4 power splitter feed sub-networks, each of which is composed of three two-stage Wilkinson power splitters 63.

[0077] In order to excite the 2×2 full-duplex antenna array, this application designs two broadband 1-to-4 power splitter feed subnetworks for the receive port and the transmit port, respectively, such as Figure 7 As shown. Each feed network consists of three two-stage Wilkinson power dividers. The circuit structure between T1, T2, T3, T4 and the transmitting port is combined into a broadband 1-to-4 power divider feed network; the circuit structure between R1, R2, R3, R4 and the receiving port is combined into another broadband 1-to-4 power divider feed network. Each two-stage Wilkinson power divider includes a first resistor RV1 and a second resistor RV2, wherein the resistance of the first resistor RV1 is 93.1 ohms; the resistance of the second resistor RV2 is 196 ohms. The two feed networks convert the transmit and receive port signals into four signals with the same amplitude and phase. The output ports of the feed network are T1 (R1), T2 (R2), T3 (R3) and T4 (R4), and are connected to the corresponding input ports of the balun. The feed network is printed on a second substrate with a thickness of 0.762 mm. The material of the second substrate is Rogers4350B (ε r =3.66 and tanδ=0.0037).

[0078] The simulation results of the feed network proposed in this application are as follows Figure 14 As shown, where S T1-TX is the transmission coefficient (or reflection coefficient) between T1 and the transmitting port, and so on. In the 2.7-3.7GHz frequency band, the average transmission coefficient of the transmitting port feeding network is about 0.28dB lower than the average transmission feeding coefficient of the receiving port feeding network. Figure 14 As shown in Figures (a) and (b), the main reason is that the microstrip line of the transmitting port feeding network is longer than the microstrip line of the receiving port. In the 2.7-3.7GHz frequency band, the reflection coefficient of the transmitting port is lower than -13.5dB, and the reflection coefficient of the receiving port is lower than -15.1dB, respectively. Figure 14 As shown in Figures (c) and (d).

[0079] The spiral full-duplex antenna array in step 4 is assembled with a feeding network consisting of four pairs of integrated baluns and two power dividers for system integration simulation. The resulting structure is as follows Figure 9 As shown in Figure (a). At a radius of π×Rg 2 The simulation results of the traditional full-duplex antenna system on the circular floor are as follows Figure 15As shown in the figure, the overlapping -10dB impedance bandwidths of the transmit and receive ports are 2.72-3.76GHz, while the 3dB axial ratio bandwidth is 2.74-3.6GHz. However, the 40dB isolation bandwidth between the transmit and receive ports is relatively narrow, only 2.81-3.6GHz, which will limit the operating bandwidth of the antenna system.

[0080] In order to broaden the 40dB isolation bandwidth, the specific structural design of this application introduces a composite metal support base (such as Figure 9 (As shown in Figure (b)); the composite metal support base contains 9 ribs evenly embedded on its inner wall. The composite metal support base has little effect on the impedance matching of the antenna. Figure 15 However, it significantly improves the isolation between the transmit and receive ports, especially around 2.75GHz. The results show that in the wideband range of 2.62-3.6GHz, the transmit and receive port isolation of more than 43.13dB is achieved, as shown in Figure (a). Figure 15 This improvement is mainly due to the fact that the cavity in the composite metal support effectively suppresses the surface waves of the metal ground plane and blocks the diffraction waves at the edge. Figure 16 The near-field electric field distribution diagram of the full-duplex antenna system at 2.75GHz is shown with and without the composite metal support. It can be seen that without the composite metal support, when the transmitting port is excited, part of the diffracted electric field energy will bypass the edge of the antenna metal floor and cause obvious interference to the receiving port, such as Figure 16 As shown in Figure (a), Figure 16 Figure (a) shows the near-field distribution of the full-duplex antenna array at 2.75 GHz when no cavity is set; Figure 16 Figure (b) shows the distribution of the near electric field of the full-duplex antenna array at 2.75GHz when the cavity is set. On the contrary, after the composite metal support is introduced, part of the diffracted electric field energy is blocked by the composite metal support, thereby reducing the interference of its propagation to the back of the antenna, as shown in Figure 2. Figure 16 In addition, the introduction of the composite cavity slightly improves the axial ratio within the working bandwidth (from <3dB to <2.8dB), and also broadens the 3dB axial ratio bandwidth of the antenna, as shown in Figure (b). Figure 15 As shown in Figure (c).

[0081] The broadband co-circularly polarized full-duplex antenna system proposed in this application was simulated, manufactured, and assembled. The entire antenna system, including the integrated balun and feed system, was simulated using CST Microwave Studio software. The simulated and tested reflection coefficients of the transmit and receive ports of the full-duplex antenna system are shown in Figure 2. Figure 17As shown in Figure (a), it shows good consistency, where Sim is the simulation result and Meas is the actual antenna test result. The -10dB impedance bandwidth of the transceiver port overlap in the simulation and test is 2.72-3.76GHz and 2.7-3.82GHz respectively. The isolation of the transceiver port in the simulation and test of the full-duplex antenna system involved in this application is shown in Figure 1. Figure 17 As shown in Figure (b). Simulation results show that the transmit and receive port isolation exceeds 40dB in the 2.6-3.6GHz frequency band and reaches a significant peak of 94.2dB at 2.93GHz. The transmit and receive port isolation tests were conducted in two different environments: one in a microwave anechoic chamber and the other in an open laboratory with multipath interference. In the anechoic chamber, the measured 40dB transmit and receive port isolation bandwidth is 2.74-3.64GHz, and reaches a peak of 71.6dB at 3.04GHz. In the open laboratory environment, despite the fluctuations caused by multipath interference, the tested isolation still exceeds 38dB in the 2.66-3.68GHz range and reaches a peak of 66.6dB at 3.13GHz.

[0082] The radiation performance of the fabricated full-duplex antenna was tested in a microwave anechoic chamber. When testing the transmit port, the receive port was connected to a 50Ω load, and vice versa. Figure 18 The simulated and tested 2D radiation patterns of the transmitting and receiving antennas in the xz and yz planes at 2.9 GHz, 3.2 GHz, and 3.6 GHz are shown. The transmitting and receiving antennas exhibit identical unidirectional circularly polarized radiation characteristics and similar radiation patterns. In the mainlobe direction, both transmitting and receiving antennas use right-hand circular polarization (RHCP) for co-polarization and left-hand circular polarization (LHCP) for cross-polarization. Sim represents the simulation results, while Meas represents the actual antenna test results.

[0083] The normal axis ratio, gain and total efficiency of the simulated and tested full-duplex antenna are shown as follows: Figure 19 As shown in Figures (a), (b), and (c). Figure 19 As shown in Figure (a), the measured 3dB axial ratio bandwidth of the transmitting and receiving antennas is 2.74-3.72GHz. Based on this, and taking into account the measured -10dB impedance bandwidth of 2.7-3.82GHz and 38dB isolation bandwidth of 2.66-3.68GHz, the test results show that the designed antenna achieves an operating bandwidth of 2.74-3.68GHz. In this operating frequency band, the transmitting antenna achieves a measured normal gain of approximately 6.44-9.73dBic, while the receiving antenna achieves 6.57-9.78dBic, as shown in the figure. Figure 19 As shown in Figure (b). Figure 19Figure (c) shows the total efficiency of the full-duplex antenna system. Within the 2.74-3.68 GHz operating frequency band, the transmit antenna's test results range from 60.3% to 66.2%, while the receive antenna's test results range from 68.65% to 75.8%. It's worth noting that the measured gain and efficiency of the full-duplex antenna system include the insertion loss caused by the balun and power splitter feed network.

[0084] This application provides a broadband, single-station, integrated, co-circularly polarized, full-duplex antenna array system. Compared to existing designs, it offers the following advantages: It combines a four-arm helical antenna array with a compact coupled structure (TCIS), comprising a central circular patch, an outer ring, and a composite cavity. By generating traveling waves at the ends of the helical arms to reduce reflected currents, it effectively addresses the low radiation efficiency and gain issues of conventional helical full-duplex antennas.

[0085] Furthermore, the antenna proposed in this application integrates a simple microstrip feeder system (four pairs of broadband integrated baluns and two broadband four-way power splitter feed networks) without using any coaxial line connections. This integration helps achieve a more compact system structure, facilitating manufacturing and reducing costs.

[0086] At the same time, the integration of the entire full-duplex antenna system ensures the stability of system performance. The design has excellent characteristics such as single-station operation, wide operating bandwidth (2.74-3.68GHz, 29.2%), high transmit / receive isolation (>38dB), good circular polarization performance (AR <3dB), high antenna efficiency (transmit antenna: 60.32%-66.2%, receive antenna: 68.65%-75.8%), and high normal gain (transmit antenna: 6.44-9.73dBic, receive antenna: 6.57-9.78dBic), while maintaining highly similar radiation patterns for the transmit and receive antennas.

[0087] The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array provided in the embodiment of the present application includes a planar full-duplex antenna radiating plate, a first substrate, an orthogonal integrated converter, a composite metal support base, a second substrate and a feeding network stacked in sequence; the outer diameter of the first substrate is smaller than the outer diameter of the second substrate, and the planar full-duplex antenna radiating plate is attached to the surface of the first substrate for arrangement; the composite metal support base is recessed inwardly on one side facing the first substrate to form a cavity; the bottom end of the orthogonal integrated converter is fixed to the bottom surface of the cavity, and the top surface of the orthogonal integrated converter supports the first substrate; both the first substrate and the second substrate are insulating substrates; the second substrate is attached to the bottom surface of the composite metal support base, and the feeding network is attached to the bottom surface of the second substrate for arrangement. The above antenna array realizes an integrated design and has the characteristics of compact structure; and there is high isolation and a small axial ratio between the transmitting and receiving ports, and high working stability.

[0088] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present application, and such modifications or substitutions should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array, characterized by: It includes a planar full-duplex antenna radiation plate, a first substrate, an orthogonal integrated converter, a composite metal support base, a second substrate and a feeding network which are stacked in sequence; The outer diameter of the first substrate is smaller than the outer diameter of the second substrate, and the planar full-duplex antenna radiation plate is attached to the surface of the first substrate for installation; the side of the composite metal support seat facing the first substrate is recessed inward to form a cavity; the bottom end of the orthogonal integrated converter is fixed to the bottom surface of the cavity, and the top surface of the orthogonal integrated converter supports the first substrate; the first substrate and the second substrate are both insulating substrates; The second substrate is attached to the bottom surface of the composite metal support base, and the feeding network is attached to the bottom surface of the second substrate for installation; The planar full-duplex antenna radiation plate includes a connecting piece and an outer ring, wherein the connecting piece is arranged at the center of the outer ring, and a plurality of four-arm spiral units are arranged between the connecting piece and the outer ring and arranged around the center of the outer ring; each of the four-arm spiral units is connected to the connecting piece and the outer ring; and the top surface of each of the orthogonal integrated converters is connected to a group of the four-arm spiral units respectively. Two adjacent microstrip lines in two adjacent groups of four-arm spiral units are coupled via a coupling cross-finger structure.

2. The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array according to claim 1 is characterized in that: The four-arm spiral unit includes four spiral microstrip lines spiraling around the same center; wherein the third spiral microstrip line is connected to the outer ring, the end of the first spiral microstrip line is coupled with the microstrip line in an adjacent group of four-arm spiral units, and the second spiral microstrip line is connected to the connecting plate and the end thereof is coupled with the microstrip line in another adjacent group of four-arm spiral units; The fourth spiral microstrip line and the first spiral microstrip line are combined into a receiving unit, and the second spiral microstrip line and the third spiral microstrip line are combined into a transmitting unit.

3. The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array according to claim 1 or 2, characterized in that: Four groups of four-arm spiral units are provided between the connecting piece and the outer ring.

4. The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array according to claim 3 is characterized in that: The spiral microstrip lines in each of the four-arm spiral units spiral outward in a counterclockwise direction.

5. The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array according to claim 4 is characterized in that: The coupled interdigital structure includes a four-arm spiral unit in which a plurality of racks are provided at the end of a microstrip line for coupling, and the racks at the end of the microstrip line are embedded in the gaps between the racks of another microstrip line.

6. The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array according to claim 1 or 2, characterized in that: An outwardly protruding flange is further provided at the outer edge of the outer ring, and the flange is arranged at the central axis of two adjacent groups of the four-arm spiral units.

7. The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array according to claim 3, characterized in that: A plurality of wing ribs are provided between the bottom surface and the inner side surface of the cavity; the end surfaces of the wing ribs are perpendicular to the bottom surface of the cavity, and the wing ribs are evenly arranged around the center of the bottom surface of the cavity.

8. The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array according to claim 3, characterized in that: The height of the orthogonal integrated converter is greater than the depth of the cavity.

9. The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array according to claim 8, characterized in that: The orthogonal integrated converter comprises a first plate and a second plate in an orthogonal combination; the first plate and the second plate are both insulating plates; A first slit is provided below the central axis of the first plate, and a second slit is provided above the central axis of the second plate; The front surface of the first plate and the front surface of the second plate are both provided with a Γ-shaped microstrip line, and the lateral feeding ends of the Γ-shaped microstrip line are both bent downward; the back surface of the first plate and the back surface of the second plate are both covered with two ground metal plates with a gap; the gap between the ground metal plates is set at the central axis of the plate; the bottom ends of the ground metal plates are connected to the bottom surface of the cavity; The four microstrip lines in the four-arm spiral unit are respectively connected to a ground metal plate.

10. The novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array according to claim 3, characterized in that: The feeding network includes two broadband 1-to-4 power splitter feeding sub-networks, each of which is composed of three two-stage Wilkinson power splitters.

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