Wide-angle scanning transmit-receive duplex common-aperture phased-array antenna

Abstract

The invention discloses a wide-angle scanning transmit-receive duplex common-aperture phased-array antenna, and belongs to the technical field of spaceborne antennas. The phased-array antenna is formed by periodically arranging and expanding a plurality of basic common-aperture units to form a dual-band dual-circular polarization structure. Each basic common-caliber unit comprises a receiving antenna unit, a transmitting antenna unit and a short-circuit grounding pi-type decoupling network. The transmitting-receiving common-caliber phased array antenna has the advantages of high unit isolation and large array scanning angle, and can meet the requirements of satellite communication, remote sensing and telemetering, mobile phone direct connection satellite communication and the like on a wide-angle scanning transmitting-receiving duplex common-caliber phased array.

Description

Technical Field

[0001] The invention relates to a wide-angle scanning transceiver duplex common-aperture phased array antenna, belonging to the technical field of satellite-borne antennas. Background Art

[0002] Both the transceiver duplex common aperture array design and wide angle scanning array design are current research hotspots in the field of satellite-borne phased arrays. The common aperture antenna array can integrate antenna arrays for different purposes in the same aperture area, significantly improving the space utilization of the array surface and making full use of satellite platform resources. Therefore, the transceiver duplex common aperture phased array antenna is very important in the field of satellite-borne antenna technology. In addition, the wide angle scanning capability of the phased array is particularly necessary in low-orbit satellites, which can meet the satellite's requirements for ground beam coverage.

[0003] Combining the two, that is, the design of a wide-angle scanning transceiver duplex co-aperture phased array antenna, has broad application prospects and research value in the fields of telemetry, remote sensing, mobile phone direct satellite communication, etc., but it is very difficult to implement. First, after the transmitting antenna and the receiving antenna are designed with a co-aperture, the density of the antenna units will increase. Secondly, due to the restriction of the large scanning angle, the spacing between the same-frequency units must be relatively small, near the half-wavelength of the corresponding operating frequency. Smaller unit spacing and co-aperture of the transceiver units will lead to reduced isolation between units and enhanced coupling, which will lead to reduced array performance, directly affecting the transmit EIRP and receive G / T value. In addition, strong inter-unit coupling will significantly reduce the beam scanning range of the phased array antenna, making wide-angle scanning difficult to achieve. In the design of wide-angle scanning transceiver duplex co-aperture phased array antenna, decoupling between units, including decoupling between receiving units, between transmitting units, and between transceiver units, has become a technical difficulty that needs to be solved urgently. At present, most of the related research at home and abroad is still only at the stage of achieving common aperture design, and the research on how to further solve the poor isolation between the same frequency and different frequencies under the condition of large-angle scanning after common aperture is still very limited. For example, in the papers "A Shared Aperture Dual-Frequency Circularly-Polarized Microstrip Array Antenna" and "Dual-band dual-circularly polarized antenna array with printed ridge gap waveguide" published in IEEE Transactions on Antennas and Propagation, dual-frequency resonant units were designed respectively, and the units were used to form an array to achieve common aperture for transmission and reception. However, no special decoupling design and large-angle beam scanning analysis were carried out. The fixed unit spacing will cause the relative spacing in the high-frequency band to become larger, which will cause the array to have obvious side lobes in the high-frequency band. The document “Dual-Band Multipolarized Aperture-Shared Antenna Array for Ku- / Ka-Band Satellite Communication” achieves multi-band co-aperture radiation by compactly placing multiple high-frequency antennas around a low-frequency antenna. However, it does not discuss the mutual coupling problem between units after the cross arrangement, nor does it perform beam scanning analysis.

[0004] In order to enable the phased array antenna system to further realize the ability of simultaneous wide-angle scanning of the transmit and receive beams on the basis of the co-aperture of duplex transmission and reception, the following technical problems need to be solved: decoupling between co-aperture antenna array units under small spacing conditions. This includes decoupling between transmitting antenna units, decoupling between receiving antenna units, and decoupling between transceiver units. After the co-aperture design, in order to meet the requirements of large-angle scanning, the unit arrangement becomes very close, resulting in enhanced coupling between units. This will lead to a series of problems such as deterioration of the antenna active standing wave, decreased gain, and decreased scanning range. Poor isolation between transceiver units will also cause the transmitted signal to interfere with the received signal, affecting the normal operation of the receiving system. Summary of the invention

[0005] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and propose a wide-angle scanning transceiver duplex co-aperture phased array antenna, so that the wide-angle scanning transceiver duplex co-aperture phased array antenna units have high isolation and realize the simultaneous wide-angle scanning capability of the transceiver beam.

[0006] The technical solution of the present invention is:

[0007] A wide-angle scanning transceiver duplex co-aperture phased array antenna, which is composed of a plurality of basic co-aperture units that are periodically arranged and extended; the basic co-aperture unit includes a receiving antenna unit, a transmitting antenna unit and a short-circuit grounded π-type decoupling network; wherein:

[0008] The receiving antenna unit adopts circular polarization radiation;

[0009] The plurality of transmitting units are sequentially rotated around the periphery of the receiving antenna unit to form a dual-band dual circular polarization structure;

[0010] The short-circuit grounded π-type decoupling network is arranged between every two adjacent transmitting antenna units.

[0011] Further, the transmitting antenna unit includes a transmitting antenna and a feeding structure for exciting the transmitting antenna;

[0012] The transmitting antenna is a circular patch antenna;

[0013] The feeding structure includes an F-type stripline and two mutually perpendicular U-shaped slots; the lengths of the two U-shaped slots correspond to the semi-dielectric wavelength of the operating frequency band of the transmitting antenna, and two mutually orthogonal electric field components with a phase difference of 90° are obtained after being excited by the F-type stripline, thereby exciting the circularly polarized radiation mode of the transmitting antenna.

[0014] Further, the receiving antenna unit includes a receiving antenna and a feeding structure for exciting the receiving antenna;

[0015] The receiving antenna is a special-shaped slotted patch antenna with cut corners on all sides;

[0016] The feeding structure is directly excited by coaxial feeding.

[0017] Furthermore, the basic common aperture unit is provided with four transmitting units, and the four transmitting units are sequentially rotated around the periphery of one receiving antenna unit, and the feeding phases are sequentially different by +90° in the counterclockwise direction.

[0018] Furthermore, the receiving units in the four basic common-aperture units are rotated and arranged in sequence and then combined to form a 2×2 combination matrix; the combination matrix is ​​periodically arranged and expanded to form a large-scale wide-angle scanning transceiver duplex common-aperture phased array.

[0019] Furthermore, the short-circuit grounded π-type decoupling network is short-circuited and connected to the ground through the metallized vias, thereby improving the isolation between adjacent transmitting antenna units.

[0020] Furthermore, the basic common-aperture unit also includes a metallized via isolation cavity, which is located at the outermost side of the basic common-aperture unit and surrounds the transmitting antenna unit and the short-circuit grounded π-type decoupling network.

[0021] Further, the interval between adjacent transmitting antenna units corresponds to the wavelength of the transmitting frequency band.

[0022] The advantages of the present invention compared with the prior art are:

[0023] (1) This invention is designed for the mobile phone direct satellite communication project carried out in my country. It proposes a wide-angle scanning transceiver duplex common aperture phased array antenna design method, which fills the technical gap in the relevant field and solves the technical problems of strong coupling between transceiver duplex common aperture antenna units and difficulty in realizing simultaneous large-angle scanning of transceiver beams. It meets all technical indicators and is innovative in antenna technology;

[0024] (2) The present invention significantly improves the isolation between adjacent transmitting units by loading a short-circuit grounded π-type decoupling network between adjacent transmitting units. This solution is innovative and can be applied to decoupling between other small-pitch, same-frequency array units;

[0025] (3) The present invention adopts different feeding methods for the transmitting antenna and the receiving antenna during design, namely the slot coupling feeding method and the coaxial excitation feeding method. The frequency selectivity presented by the half-wavelength resonance characteristics of the two U-shaped slots used to excite the transmitting antenna significantly improves the isolation between the transmitting antenna and the receiving antenna. This solution can be used as a reference for the design of other co-aperture arrays in different frequency bands;

[0026] (4) The antenna structure adopted by the present invention realizes dual-band dual circular polarization radiation in the basic common aperture unit. By adopting the sequential rotation feeding of the four transmitting units inside the common aperture unit and the sequential rotation feeding of the 2×2 receiving units, the axial ratio characteristics of the antenna array in the transmitting frequency band and the receiving frequency band and the radiation performance during large-angle scanning are improved respectively. It can be used as a reference for other large-angle scanning circular polarization arrays;

[0027] (5) The antenna design method can not only be used for the design of satellite-borne phased arrays for mobile phone direct satellite communication projects, but can also be used in other fields such as satellite communication, telemetry and remote sensing, which require the realization of common aperture large-angle scanning for transmission and reception. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0029] Figure 1 This is a schematic diagram of a basic unit of a common aperture array antenna according to an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the feeding structure of a transmitting antenna according to an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the structure of a 4×4 sub-array of a common aperture array according to an embodiment of the present invention;

[0032] Figure 4 This is a diagram showing the correspondence between the S-band and C-band unit excitation ports in a subarray according to an embodiment of the present invention;

[0033] Figure 5 The coupling curve between S-band units in the subarray of the embodiment of the present invention;

[0034] Figure 6 The coupling curve between C-band units in the subarray of the embodiment of the present invention;

[0035] Figure 7 The coupling curve between the S-band unit and the adjacent C-band unit in the subarray according to the embodiment of the present invention;

[0036] Figure 8 The scanning pattern and axial ratio curve of the sub-array in the S-band of the embodiment of the present invention, (a) is the gain pattern, (b) is the curve of the axial ratio changing with the scanning angle;

[0037] Fig. 9 The scanning pattern and axial ratio curve of the sub-array in the C-band of the embodiment of the present invention, (a) is the gain pattern, and (b) is the curve of the axial ratio changing with the scanning angle. DETAILED DESCRIPTION

[0038] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0039] The present invention proposes a wide-angle scanning transceiver duplex co-aperture phased array antenna, taking the wide-angle scanning co-aperture array design of receiving left-hand circularly polarized waves in the S band and radiating right-hand circularly polarized waves in the C band as an example. Figure 1 to Figure 3 As shown in the figure, a basic unit includes 1 S-band unit and 4 C-band units, 4 short-circuit grounded π-type decoupling networks, and 1 metallized via isolation cavity. The side length of the basic common aperture unit is 80mm, so that after the array is formed, the spacing between the S units corresponds to 0.525 wavelengths of the receiving frequency band 1.97GHz, and the spacing between the C units corresponds to 0.473 wavelengths of the transmitting frequency band 3.55GHz, to ensure that both the transmitting and receiving beams can achieve a scanning range of no less than ±51°.

[0040] The C-band unit serves as a transmitting antenna unit, including a circular microstrip patch antenna 1-3 with slot-coupled feeding excitation and its feeding structure 1-4, that is, the circular patch with slot-coupled excitation realizes left-hand circular polarization. The S-band unit serves as a receiving antenna unit, including a special-shaped microstrip patch antenna 1-1 with surface slots and its feeding structure 1-2, which is a special-shaped circular patch with coaxial feeding, and realizes right-hand circular polarization by using surface slots. The transmitting antenna unit surrounds the receiving antenna unit to form a basic co-aperture unit with dual-band dual circular polarization. The S-band unit and the C-band unit share the same radiation aperture by cross-arrangement.

[0041] A set of short-circuit grounded π-type decoupling networks 1-5 is loaded between every two adjacent transmitting antennas 1-3 to improve the co-frequency isolation between transmitting units. The short-circuit grounded π-type decoupling networks 1-5 are composed of metal wires and metallized vias printed in the dielectric board. Each basic unit contains 4 sets of such decoupling networks. The π-type decoupling network is short-circuited and connected to the ground through the metallized vias, which can improve the isolation between adjacent transmitting antennas.

[0042] The transmitting antenna feeding structure 1-4 includes an F-type stripline and two orthogonal U-shaped slots. There are two mutually perpendicular U-shaped slots on the floor, and the F-type stripline is used to excite two sets of electric fields with equal amplitudes, orthogonal to each other, and 90° difference, respectively, so as to realize left-hand circular polarization radiation. The lengths of these two U-shaped slots 2×L1+L2 and 2×L3+L4 both correspond to about half the medium wavelength of the operating frequency band of the transmitting antenna. The frequency selection characteristics of the half-wavelength U-shaped slot improve the isolation between the transmitting antenna and the receiving antenna, and reduce the influence of the transmitting antenna on the receiving antenna after the co-aperture design.

[0043] The metallized via isolation cavity 1-6 is located outside the basic common aperture unit and surrounds the common aperture basic unit, which can limit the electric field propagation inside the dielectric plate and the surface wave propagation along the dielectric surface, thereby improving the isolation between the receiving antennas after the array is formed.

[0044] The high isolation characteristics between the transmitting units, between the receiving units, and between the transceiver units enable the designed co-aperture array to achieve a large scanning gain without significant loss of gain for both the transmitting and receiving beams. The sequential rotation feeding method combined with the dual-band dual circular polarization basic co-aperture unit can improve the axial ratio of the transmitting antenna and the receiving antenna during large-angle scanning.

[0045] The 4 C-band units are arranged in a sequential rotation manner and the feeding phases are different by +90° in the counterclockwise direction. The 2×2 receiving antennas and their feeding networks are arranged in a sequential rotation manner and the feeding phases are different by -90° in the counterclockwise direction. With this 2×2 co-aperture basic unit periodic arrangement, the following can be obtained: Figure 3 The structure of the duplex co-aperture subarray shown is composed of 8×8 S-band units and 16×16 C-band units. This subarray can be further spliced ​​into a large-scale array. Figure 4 The corresponding diagram of the ports of the S-band unit and the C-band unit in the subarray is given.

[0046] like Figure 4 and Figure 5 As shown, S1 is the S-band unit at the center of the subarray, and the isolation between it and other surrounding S units is greater than 18.2 dB in the entire range of 1.92 to 2.025 GHz.

[0047] like Figure 4 and Figure 6 As shown, C2 is a C-band unit located at the center of the subarray. After using a short-circuited π-type decoupling network, the isolation between it and other surrounding C units is greater than 16.7 dB in the entire 3.44-3.66 GHz range.

[0048] like Figure 4 and Figure 7As shown, the isolation between the S1 unit and the surrounding C-band units is greater than 37dB in the range of 1.92 to 2.025GHz.

[0049] like Figure 8 (a) and (b) show the scanning pattern and axial ratio curve of the subarray in the S-band. It can be seen that when scanning from 0° to 51°, the gain decreases by less than 4dB and the axial ratio is less than 1.54dB.

[0050] like Fig. 9 (a) and (b) show the scanning radiation pattern and axial ratio curve of the sub-array in the C-band. It can be seen that when scanning from 0° to 51°, the gain decreases by less than 3dB and the axial ratio is less than 4dB.

[0051] The present invention is designed to address the needs of wide-angle scanning transceiver duplex common-aperture phased array antennas, and solves the technical bottleneck of poor isolation between units in the array under the constraint that both the transceiver beams can scan at a wide angle. The present invention is not only suitable for satellite communications, remote sensing and telemetry, and mobile phone direct satellite communications, but can also be used in the field of ground communications, and therefore has strong practicality and broad market application value.

[0052] Parts of the present invention that are not described in detail belong to common knowledge among those skilled in the art.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. For those skilled in the art, without paying creative labor, several modifications and substitutions can be made to the present invention. For example, a simple proportional transformation can be used to obtain a L / S dual-frequency co-aperture, Ku / Ka dual-frequency co-aperture array array and other dual-band frequency ratios close to 1:2, such as a transceiver duplex co-aperture array antenna. The feeding structure can also be simply mirrored to change the polarization mode of the antenna, thereby obtaining the characteristics of receiving right-handed circularly polarized waves and radiating left-handed circularly polarized waves. All these modifications and substitutions should be covered within the scope of protection of the present invention.

Claims

1. A wide-angle scanning transceiver duplex common-aperture phased array antenna, characterized in that: It is composed of a plurality of basic co-aperture units that are periodically arranged and extended; the basic co-aperture unit includes a receiving antenna unit, a transmitting antenna unit and a short-circuited grounded π-type decoupling network; wherein: The receiving antenna unit adopts circular polarization radiation; The plurality of transmitting units are sequentially rotated around the periphery of the receiving antenna unit to form a dual-band dual circular polarization structure; The short-circuit grounded π-type decoupling network is arranged between every two adjacent transmitting antenna units.

2. The wide-angle scanning transceiver duplex common-aperture phased array antenna according to claim 1, characterized in that: The transmitting antenna unit comprises a transmitting antenna and a feeding structure for exciting the transmitting antenna; The transmitting antenna is a circular patch antenna; The feeding structure includes an F-type stripline and two mutually perpendicular U-shaped slots; the lengths of the two U-shaped slots correspond to the semi-dielectric wavelength of the operating frequency band of the transmitting antenna, and two mutually orthogonal electric field components with a phase difference of 90° are obtained after being excited by the F-type stripline, thereby exciting the circularly polarized radiation mode of the transmitting antenna.

3. The wide-angle scanning transceiver duplex common-aperture phased array antenna according to claim 1, characterized in that: The receiving antenna unit comprises a receiving antenna and a feeding structure for exciting the receiving antenna; The receiving antenna is a special-shaped slotted patch antenna with cut corners on all sides; The feeding structure is directly excited by coaxial feeding.

4. The wide-angle scanning transceiver duplex common-aperture phased array antenna according to claim 1, characterized in that: The basic common aperture unit is provided with four transmitting units, and the four transmitting units are sequentially rotated around the periphery of one receiving antenna unit, and the feeding phases are sequentially different by +90° in the counterclockwise direction.

5. The wide-angle scanning transceiver duplex common-aperture phased array antenna according to claim 4, characterized in that: The receiving units in the four basic common-aperture units are rotated and arranged in sequence and then combined to form a 2×2 combination matrix; the combination matrix is ​​periodically arranged and expanded to form a large-scale wide-angle scanning transceiver duplex common-aperture phased array.

6. The wide-angle scanning transceiver duplex common-aperture phased array antenna according to claim 1, characterized in that: The short-circuit grounded π-type decoupling network is short-circuited to the ground through metallized vias, thereby improving the isolation between adjacent transmitting antenna units.

7. The wide-angle scanning transceiver duplex common-aperture phased array antenna according to claim 1, characterized in that: The basic common-aperture unit also includes a metallized via isolation cavity, which is located at the outermost side of the basic common-aperture unit and surrounds the transmitting antenna unit and the short-circuit grounded π-type decoupling network.

8. The wide-angle scanning transceiver duplex common-aperture phased array antenna according to claim 1, characterized in that: The spacing between adjacent transmitting antenna elements corresponds to the wavelength of the transmitting frequency band.

Images