Novel broadband single-station concircularly polarized co-frequency simultaneous full duplex antenna array

Abstract

The invention discloses a novel broadband single-station concircularly-polarized co-frequency simultaneous full-duplex antenna array. The antenna array comprises a planar full-duplex antenna radiation plate, a first substrate, an orthogonal integrated converter, a composite metal supporting seat, a second substrate and a feed network which are stacked in sequence, the outer diameter of the first substrate is smaller than that of the second substrate, and the planar full-duplex antenna radiant panel is attached to the surface of the first substrate; the side face, facing the first substrate, of the composite metal supporting base is recessed inwards to form a cavity. The bottom end of the orthogonal integrated converter is fixed on 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 insulating substrates; the second substrate is attached to the bottom surface of the composite metal supporting seat, and the feed network is attached to the bottom surface of the second substrate. The antenna array realizes integrated design and has the characteristic of compact structure; moreover, the receiving and transmitting ports have high isolation and small axial ratio, and the working stability is high.

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 frequency band efficiency and expanding system capacity are the eternal pursuits in the field of wireless communications. However, traditional system capacity expansion technologies have reached their limits. Today, simultaneous transmit and receive (STAR), also known as in-band full-duplex (IBFD), has attracted much attention as a promising approach. Because full-duplex antenna technology allows wireless devices to transmit and receive signals simultaneously on the same frequency, it has great potential to further double the spectrum efficiency and system capacity compared to current half-duplex communications.

[0003] The key challenge in designing a full-duplex antenna system is that self-interference (SI) signals must be eliminated in both the transmit and receive links. The degree of self-interference cancellation (SIC) required varies by application and is typically more than 110 dB. To achieve a high level of self-interference cancellation, different self-interference cancellation techniques are used in the antenna, analog, and digital domains. Achieving a high level of self-interference cancellation in the antenna domain can reduce the burden of suppressing self-interference in other domains and reduce the complexity of the full-duplex antenna system.

[0004] In the field of antennas, in addition to high isolation between the transmitting and receiving antennas, the transmitting and receiving antennas are often required to have the same polarization (co-linear polarization (Co-LP) or co-circular polarization (Co-CP)) and similar radiation patterns, which makes antenna design more challenging. To achieve this goal, a variety of self-interference elimination technologies have been developed in the field of antennas, including near-field cancellation, mode orthogonality, common mode (CM) and differential mode (DM) elimination, loading decoupling structure or circuit, dual-polarization sequential rotation array, and so on.

[0005] The quadrifilar helical antenna is usually used to design a broadband co-circularly polarized full-duplex antenna with normal radiation. By taking advantage of the geometric symmetry of the quadrifilar helical antenna, two of the balun feed arms are used as transmitting antennas, while the other two arms orthogonal to them are used as receiving antennas, which can theoretically achieve infinite isolation between the transmitting and receiving antennas. However, the conventional quadrifilar helical antenna is an antenna that is based on the radiation of the traveling wave structure and is independent of the frequency. In order to achieve better circular polarization performance (low axial ratio (AR)), it is usually necessary to connect their ends with resistors or spiral wires to reduce the influence of the reflection at the end of the parasitic arm, or use absorbing materials as an absorbing backing on the back. However, these methods will lead to a decrease in antenna gain and radiation efficiency. In order to improve the normal gain and antenna efficiency, some scholars have proposed a method of loading a lens load on the radiating side of the helical antenna and loading a metal cavity on the back. However, this results in a significant increase in the antenna structure. In addition, the use of commercial off-the-shelf (COTS) components to build the feeding network and the use of multiple coaxial cables to connect the helical antennas results in a complex and non-compact 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 low efficiency of simultaneous transmitting and receiving antennas in the prior art 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 seat, a second substrate and a feeding network which are 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 arrangement; the composite metal support seat 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; 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 seat, and the feeding network is attached to the bottom surface of the second substrate for arrangement;

[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 groups of four-arm spiral units arranged around the outer periphery of the center of the outer ring are arranged between the connecting piece and 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 respectively connected to a group of the four-arm spiral units;

[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-circular polarization co-frequency simultaneous full-duplex antenna array, wherein the four-arm spiral unit comprises four spiral microstrip lines spiraling around the same center of a circle; 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 piece and the end thereof is coupled with 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] The novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array, wherein 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 end for coupling in a four-arm spiral unit having a plurality of racks, 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, wherein the outer edge of the outer ring is also provided with a flange protruding outward, and the flange is arranged at the central axis of two adjacent groups of the four-arm spiral units.

[0019] The novel broadband single-station co-circularly polarized same-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-circularly polarized same-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 that are orthogonally combined; 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 of the first plate and the front of the second plate are both provided with a Γ-shaped microstrip line, and the transverse feeding ends of the Γ-shaped microstrip line are both bent downward; the back of the first plate and the back of the second plate are both covered with two ground metal plates with gaps; 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-circularly polarized co-frequency simultaneous full-duplex antenna array, wherein the feeding network includes two broadband 1-to-4 power divider feeding sub-networks, each of which is composed of three two-stage Wilkinson power dividers.

[0026] The embodiment of the present application provides a novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array, including a planar full-duplex antenna radiating plate, a first substrate, an orthogonal integrated converter, a composite metal support seat, 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 seat 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; 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 seat, 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 a high isolation and a small axial ratio between the transmitting and receiving ports, and the working stability is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. 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 paying any creative work.

[0028] Figure 1 An exploded 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;

[0029] Figure 2 A top 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;

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

[0031] Figure 4 Provided in the embodiments of this application Figure 2 The local structure 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-circular polarization 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 A schematic diagram of the processing process of a planar full-duplex antenna radiator in a novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0036] Fig. 9 A three-dimensional structure comparison 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;

[0037] Fig.10 A schematic diagram of the effect of a novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0038] Fig.11 A schematic diagram of the effect of a novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0039] Fig.12 A schematic diagram of the effect of a novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0040] Fig.13 A schematic diagram of the effect of a novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0041] Fig.14 A schematic diagram of the effect of a novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0042] Fig.15 A schematic diagram of the effect of a novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0043] Fig.16 A schematic diagram of the effect of a novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0044] Fig.17 A schematic diagram of the effect of a novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0045] Fig.18 A schematic diagram of the effect of a novel broadband single-station co-circularly polarized co-frequency simultaneous full-duplex antenna array provided in an embodiment of the present application;

[0046] Fig.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. feeding 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 the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0049] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

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

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

[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, including a planar full-duplex antenna radiation plate 1, a first substrate 2, an orthogonal integrated converter 3, a composite metal support seat 4, a second substrate 5 and a feeding network 6 which are 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 seat 4 is recessed inwardly 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 seat 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 seat 4 may all be circular. In a specific embodiment, 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, 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 arranged around the center of the outer ring 12 are arranged between the connecting piece 11 and 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; and the two adjacent microstrip lines in two adjacent groups of the four-arm spiral units 13 are coupled through a coupling cross-finger structure 14.

[0058] Among them, 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 circular polarization 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 in 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 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. Among them, 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, in order to achieve infinite isolation between the transmitting and receiving ports, in the four-arm spiral unit 13, two spiral microstrip lines (spiral arms) are used as transmitting units, and the other two spiral microstrip lines (spiral arms) placed orthogonally thereto are used as receiving units. The four four-arm spiral units 13 are fed with equal amplitude and phase to form a 2×2 array. The radiation aperture of the antenna is printed on the first substrate 2, and the relative dielectric constant (εr) of the first substrate 2 is 3.66 and the dielectric loss tangent (tanδ) is 0.0037; the first substrate 2 is also a circular substrate with a radius of R1 (made of Rogers 4350B) and a thickness of h1; similarly, the second substrate 5 can be set as 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 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, it 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-hand circularly polarized, that is, the spiral microstrip lines are both 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 spiral units 13, each of which has 1.5 turns. The reflection coefficient of the array is shown in Fig.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. Fig.10 As shown in Figure (b), based on the antenna structure in step 1, the normal axial ratio is tested in the frequency band range of 2.6-3.8 GHz, and the normal axial ratio exceeds 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 minimized. 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, Figure 3 As shown, the coupled interdigital structure 14 includes a plurality of racks 141 at the end of a microstrip line for coupling in a four-arm spiral unit 13, and the racks 141 at the end of the microstrip line 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 Fig.11 As shown, Fig.11 is the current distribution of two adjacent four-arm spiral units 13 at different phase angles at 3.2 GHz, Fig.11 The phase angle corresponding to the middle (a) figure is 0°; Fig.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 Fig.12 As shown, Fig.12 is the current distribution of different phase angles on the outer ring 12 at 3.2GHz, Fig.12 The phase angle corresponding to the middle (a) figure is 0°; Fig.12 The phase angle corresponding to Figure (b) is 90°.

[0066] Step 4: In order to broaden the axial ratio bandwidth of the antenna, step 4 introduces a circular connecting piece 11 at the center of the array, such as 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. Fig.13 The current distribution on a single spiral is shown with and without the circular connecting piece 11. Fig.13 Figure (a) shows the test result without the circular connecting piece 11; Fig.13 Figure (b) shows the test result of setting the circular connecting piece 11. It can be seen that by introducing the circular connecting piece 11, part of the current on arm-2 is diverted to the circular connecting piece 11, which can effectively reduce the current along arm-2. In addition, the coupling current from arm-2 to arm-4 is greatly reduced, thereby weakening the reflected current at the end of arm-4, as shown in FIG. Fig.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, so that the antenna axial ratio in step 4 is significantly improved. 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 is kept below -10dB, as shown in FIG. Fig.10 As shown in Figure (a).

[0067] In a more specific embodiment, Figure 1 and Fig. 9 As shown, a flange 121 protruding outward is further provided at the outer edge of the outer ring 12 , 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 may 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 comprises a first plate 31 and a second plate 32 for orthogonal combination; the first plate 31 and the second plate 32 are both insulating plates; a first slot 311 is provided at the lower part of the central axis of the first plate 31, and a second slot 312 is provided at the upper part of 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, and the transverse feeding end of the Γ-shaped microstrip line 33 is 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 set at the central axis of the plate; the bottom ends of the ground metal plates 34 are connected to the bottom surface of the cavity 41; the four microstrip lines in the four-arm spiral unit 13 are respectively connected to a ground metal plate 34. TX is for transmission and RX is for reception.

[0072] The orthogonal integrated converter 3 is also an orthogonal integrated balun (balanced-unbalanced converter, Integrated Balun). In order to realize the orthogonal differential feeding of the four-arm spiral unit 13 and ensure a good match 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, each balun consists of a Γ-shaped microstrip line 33 on the front side and a balun ground with a gap on the back side. Both baluns are built on a Rogers 4350B substrate in a vertical direction, and they 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 side of the flat plate (dielectric substrate), as shown in FIG. Figure 6 As shown in Figure (a) in Figure 1, 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 1. 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 currents to the spiral unit, thereby achieving effective differential feeding. It is worth mentioning 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. Such an improvement ensures that there is no direct contact between the microstrip feeding point of one balun and the substrate of another balun, thereby reducing the feeding phase deviation.

[0073] In a specific embodiment, the dimension values ​​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 feeding network 6 includes two broadband 1-to-4 power splitter feeding 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, the present application designs two broadband 1-to-4 power splitter feed subnetworks for the receiving port and the transmitting port, respectively, such as Figure 7 As shown. Each feed network consists of three two-stage Wilkinson power dividers, so 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), respectively, 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, and the material of the second substrate is Rogers4350B (ε r =3.66 and tanδ=0.0037).

[0078] The simulation results of the feeding network proposed in this application are as follows Fig.14 As shown, 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. Fig.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. Fig.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 Fig. 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 Fig.15As shown in the figure, it can be seen that the overlapping part of the -10dB impedance bandwidth of the transmitting port and the receiving port is 2.72-3.76GHz, while the 3dB axial ratio bandwidth is 2.74-3.6GHz. However, the 40dB isolation bandwidth of the transmitting and receiving ports is relatively narrow, only 2.81-3.6GHz, which will limit the working bandwidth of the antenna system.

[0080] In order to broaden the 40dB isolation bandwidth, the specific structural design of the present application introduces a composite metal support base (such as Fig. 9 The composite metal support seat has 9 ribs evenly embedded on its inner wall. The composite metal support seat has little effect on the impedance matching of the antenna. Fig.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). Fig.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. Fig.16 The near-field electric field distribution diagram of the full-duplex antenna system at 2.75GHz with and without the composite metal support is shown. It can be seen that without the introduction of 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 Fig.16 As shown in Figure (a), Fig.16 The middle figure (a) shows the distribution of the near electric field of the full-duplex antenna array at 2.75GHz when no cavity is set; Fig.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, thus reducing the interference of its propagation to the back of the antenna, such as Fig.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). Fig.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 1. Fig.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 Fig.17 As shown in Figure (b). The simulation results show that within the 2.6-3.6GHz frequency band, the isolation of the transceiver ports exceeds 40dB, and reaches a significant peak of 94.2dB at 2.93GHz. The isolation of the transceiver ports was tested in two different environments: one is a microwave darkroom, and the other is an open laboratory with multipath interference. In the darkroom environment, the measured 40dB transceiver 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 processed full-duplex antenna was tested in a microwave darkroom. When testing the transmit port, the receive port was connected to a 50Ω load, and vice versa. Fig.18 The simulated and tested two-dimensional 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. It can be seen that the transmitting and receiving antennas have the same unidirectional circular polarization radiation characteristics and similar radiation patterns. In the main lobe direction, the transmitting and receiving antennas are co-polarized with right-hand circular polarization (RHCP) and cross-polarized with left-hand circular polarization (LHCP), where Sim is the simulation result and Meas is the actual antenna test result.

[0083] The simulated and tested normal axis ratio, gain and total efficiency of the full-duplex antenna are shown in Fig.19 As shown in Figures (a), (b), and (c). Fig.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 considering 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 about 6.44-9.73dBic, and the receiving antenna achieves 6.57-9.78dBic, as shown in the figure. Fig.19 As shown in Figure (b). Fig.19Figure (c) shows the total efficiency of the entire full-duplex antenna system. In the operating frequency band of 2.74-3.68GHz, the test results of the transmitting antenna range from 60.3% to 66.2%, and the test results of the receiving antenna range from 68.65% to 75.8%. It is worth noting that the measured gain and efficiency of the full-duplex antenna system include the insertion loss caused by the balun and power divider feeding network.

[0084] The present application provides a broadband single-station integrated co-circularly polarized full-duplex antenna array system, which has the following advantages over existing designs: it combines a four-arm helical antenna array with a compact coupled structure (TCIS), and includes a centrally placed circular patch, an outer circular ring, and a composite cavity. By using a method of generating traveling waves at the ends of the helical arms to reduce reflected currents, the problem of low radiation efficiency and gain of previous helical full-duplex antennas is effectively solved.

[0085] In addition, the antenna proposed in this application integrates a simple microstrip feeder system (four pairs of broadband integrated baluns and two broadband four-way power divider feeder networks) without using any coaxial line connection. Such integration helps to achieve a more compact system structure, is more convenient for manufacturing, and reduces 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 of 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 radiation plate, a first substrate, an orthogonal integrated converter, a composite metal support seat, 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 arrangement; the composite metal support seat 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; 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 seat, 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 a high isolation and a small axial ratio between the transmitting and receiving ports, and the working stability is high.

[0088] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A novel broadband single-station co-circular polarization co-frequency simultaneous full-duplex antenna array, characterized in that: It includes a planar full-duplex antenna radiation plate, a first substrate, an orthogonal integrated converter, a composite metal support seat, 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 arrangement; the composite metal support seat 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; 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 seat, and the feeding network is attached to the bottom surface of the second substrate for arrangement; 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 groups of four-arm spiral units arranged around the outer periphery of the center of the outer ring are arranged between the connecting piece and 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 respectively connected to a group of the four-arm spiral units; 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 arranged 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 cross-finger structure includes a four-arm spiral unit in which a microstrip line end for coupling is provided with a plurality of racks, and the racks at the end of the microstrip line are embedded in the gap 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: A flange protruding outward is also 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 is characterized in that: A plurality of wing ribs are also 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 is 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 is characterized in that: The orthogonal integrated converter comprises a first plate and a second plate that are orthogonally combined; 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 of the first plate and the front of the second plate are both provided with a Γ-shaped microstrip line, and the transverse feeding ends of the Γ-shaped microstrip line are both bent downward; the back of the first plate and the back of the second plate are both covered with two ground metal plates with gaps; 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 is 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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