Ku-band broadband wide-beam low-axial-ratio circularly polarized antenna

Abstract

The utility model relates to a Ku-waveband broadband wide-beam low-axial-ratio circularly polarized antenna, and belongs to the technical field of antennas. Comprising an antenna oscillator, an antenna base plate, a broadband phase shift feed network plate, a network cavity and a radio frequency connector, the antenna oscillator is fixed on the front surface of the antenna bottom plate and adopts a crisscross dipole form; the broadband phase shift feed network board is embedded in the back surface of the antenna bottom board; the network cavity is fixed on the back surface of the antenna bottom plate and tightly presses the broadband phase shift feed network plate; and the radio frequency connector is fixed on the back surface of the network cavity and is used for feeding the whole antenna. The antenna oscillator provided by the utility model not only can reduce the profile of the antenna, but also can obtain a stable directional diagram in a wide frequency band, and the bent structure of the oscillator arms enables the beam width of the antenna to be broadened; the broadband phase-shift feed network board broadens the bandwidth of the phase-shift feed network by adopting a mode of loading open and short circuit branches in parallel, and the low axial ratio characteristic in the broadband of the antenna is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of broadband circularly polarized antennas, and in particular relates to a Ku-band circularly polarized antenna with wide bandwidth beam and low axial ratio. Background Art

[0002] Circularly polarized antennas enable wireless communication between moving receiver and transmitter carriers. They not only enhance interference immunity but also significantly reduce polarization loss during signal transmission compared to linearly polarized antennas. Axial ratio is a key indicator of an antenna's circular polarization performance. With the continuous advancements in satellite navigation, autonomous driving, and modern information-based military fields, antennas, as crucial components for wireless communication on high-speed moving carriers, must not only exhibit excellent circular polarization performance but also typically possess wide beam coverage and a wide bandwidth to meet the carrier's wide-angle communication needs. Utility Model Content

[0003] The technical problems to be solved by this utility model are:

[0004] In order to avoid the shortcomings of the existing technology, the present invention provides a Ku-band circularly polarized antenna with wide bandwidth and low axial ratio, which is used to solve the problems of wide beam (120° beam range gain ≥ 0dBic) and low axial ratio (≤ 2dB axial ratio bandwidth greater than 40%) of the existing Ku-band broadband circularly polarized antenna.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A Ku-band wide-bandwidth beam low-axial-ratio circularly polarized antenna, characterized by comprising: an antenna element, an antenna base plate, a broadband phase-shifted feed network board, a network cavity, and a radio frequency connector;

[0007] The antenna element is fixed to the front side of the antenna base plate;

[0008] The broadband phase-shifted feed network board is embedded in the back of the antenna base plate;

[0009] The network cavity is fixed to the back of the antenna base plate, pressing the broadband phase-shifted feed network board tightly;

[0010] The radio frequency connector is fixed to the back of the network cavity, passes through the network cavity and is connected to the broadband phase-shift feeding network board, so as to feed the entire antenna.

[0011] A further technical solution of the present invention is as follows: the antenna element is in the form of a cross-printed dipole, including two cross-shaped antenna substrates, and a microstrip feeding balun and a microstrip printed element are printed on the front and back sides of each antenna substrate respectively, and the element arm of the microstrip printed element adopts a bent structure.

[0012] A further technical solution of the present invention is as follows: a metallized hole is designed on the antenna substrate where the microstrip printed vibrator in the two cross-intersecting antenna substrates is not cut off, which is used to reconnect the microstrip printed vibrator cut off by the cutting seam by soldering, so that the antenna vibrator is more symmetrical in structure, thereby reducing the antenna axial ratio.

[0013] A further technical solution of the present invention is as follows: a groove for fixing the antenna vibrator is reserved on the front side of the antenna base plate.

[0014] A further technical solution of the present invention is as follows: the antenna base plate also includes a welding window cover and a group of coaxial structures, the coaxial structure is used to connect the antenna vibrator and the broadband phase-shift feeding network board to realize antenna feeding, and the welding window cover protects the welding points on the broadband phase-shift feeding network board.

[0015] A further technical solution of the present invention is as follows: the broadband phase-shifted feed network board includes a network layer substrate, a microstrip feed network and a network layer ground. The microstrip feed network adopts a branch-loaded phase shifter, and two groups of open-short-circuited branches are connected in parallel, so that the broadband phase-shifted feed network board can achieve broadband phase stability and ensure small phase error under wide bandwidth.

[0016] A further technical solution of the present invention is as follows: the length of the short-circuit branch is between 0.1λ0 and λ0, wherein λ0 is the wavelength of the center frequency medium.

[0017] A further technical solution of the present invention is as follows: the network cavity includes a network outer cavity, a network inner cavity and a network cavity bottom plate. The network inner cavity isolates the microstrip feeding network and the network layer from each other, thereby eliminating the resonance point of the broadband phase-shifted feeding network board in the cavity.

[0018] A further technical solution of the present invention is that it also includes an antenna protection cover located at the outer ring of the antenna vibrator, and the antenna protection cover is fixed to the antenna base plate to provide dust-proof protection for the antenna vibrator.

[0019] A further technical solution of the present invention is that the antenna protection cover is made of a material with a low dielectric constant.

[0020] The beneficial effects of the present invention are:

[0021] This utility model provides a Ku-band circularly polarized antenna with a wide bandwidth, low axial ratio, and excellent circular polarization characteristics within the 12GHz-18GHz frequency band. It achieves an axial ratio of ≤2dB across the entire frequency band and an antenna gain of ≥0dB within a 120° beamwidth in the azimuth plane. The antenna is compact and lightweight, weighing no more than 40g. Compared with existing technologies, it has the following advantages:

[0022] 1. The antenna dipole arm of the utility model adopts a bent structure, which introduces a current perpendicular to the antenna base plate to achieve the widening of the directional pattern beam width.

[0023] 2. The antenna substrate of this utility model is equipped with metallized holes. Through the metallized holes, the microstrip printed vibrator that was cut off during the engineering process is reconnected by soldering, making the antenna vibrator more symmetrical in structure, thereby reducing the antenna axial ratio. This solves the problem of disconnection of microstrip printed vibrators that cannot be avoided in actual processing.

[0024] 3. The phase-shifting feed network of the present invention adopts a branch-loaded phase shifter, with two sets of open-short-circuited branches connected in parallel (the length is between 0.1λ0 and λ0, where λ0 is the wavelength of the center frequency medium). This enables the phase-shifting feed network to achieve broadband phase stability and can excite a current with a 90° phase difference within the 12-18 GHz frequency band. At the same time, it ensures a small phase error (error ±6°) over a wide bandwidth, thus ensuring the circular polarization characteristics of the antenna within the wide bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are only used for the purpose of illustrating specific embodiments and are not to be considered as limiting the present invention. Throughout the accompanying drawings, the same reference symbols denote the same components.

[0026] Figure 1 This is the overall structural appearance diagram of the utility model;

[0027] Figure 2 This is a back view of the overall structure of the utility model;

[0028] Figure 3 This is an exploded view of the structure of the present utility model;

[0029] Figure 4 This is a structural diagram of the antenna element of the present utility model;

[0030] Figure 5 This is an exploded view of the antenna element of the present invention;

[0031] Figure 6 This is a structural diagram of the antenna protection cover of the present utility model;

[0032] Figure 7 This is a structural diagram of the antenna base plate of the present utility model;

[0033] Figure 8 This is a back view of the antenna base plate of the present invention;

[0034] Figure 9 This is a structural diagram of the broadband phase-shifted feed network board of the utility model;

[0035] Figure 10 This is a back view of the broadband phase-shifted feeding network board of the present utility model;

[0036] Figure 11 This is a diagram of the network cavity structure of the utility model;

[0037] Figure 12 This is a back view of the network cavity of the present invention;

[0038] Figure 13 This is a structural diagram of the radio frequency connector of the present utility model;

[0039] Figure 14 This is a screenshot of the simulation of the axis ratio within the frequency band of the present invention;

[0040] Figure 15 This is a screenshot of the beam width simulation of the utility model.

[0041] In the picture:

[0042] 1-antenna element; 2-antenna protection cover; 3-antenna base plate; 4-broadband phase-shifted feed network board; 5-network cavity; 6-RF connector; 101-antenna substrate; 102-microstrip feed balun; 103-microstrip printed element; 104-metallized hole; 105-ground pad; 106-cutting seam; 301-welding window cover; 302-coaxial structure; 303-first groove; 304-second groove; 305-sinking structure; 401-network layer substrate; 402-microstrip feed network; 403-network layer ground; 501-network external cavity; 502-network inner cavity; 503-network cavity bottom plate; 504-feeding hole; 601-inner conductor; 602-dielectric; 603-housing. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0044] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0045] like Figures 1 to 3 As shown, an embodiment of the present invention proposes a Ku-band wide-bandwidth beam low-axial ratio circularly polarized antenna, including an antenna element 1, an antenna protective cover 2, an antenna cavity 3, a broadband phase-shifted feed network board 4, a network cavity 5, and a radio frequency connector 6.

[0046] like Figures 4 and 5 As shown, the antenna element 1 is in the form of a cross-printed dipole, which includes an antenna substrate 101, a microstrip feeding balun 102 and a microstrip printed element 103. The element arm of the microstrip printed element 103 adopts a bent structure, and a current perpendicular to the antenna base plate 3 is introduced to achieve the widening of the beam width of the directional pattern. By adjusting the width and length of the microstrip feeding balun 102, the conversion from unbalanced impedance to balanced impedance is achieved.

[0047] In actual engineering, to cross-fix the two antenna elements into a cross structure, a cut slit 106 is created. This cut slit 106 disconnects one of the microstrip printed elements 103. Antenna element 1 is provided with a set of pre-reserved metallized holes 104, which are used to reconnect the microstrip printed elements 103 that were severed by the cut slit 106 via soldering. This makes the antenna element more symmetrical and reduces the antenna axial ratio. Furthermore, a set of ground pads 105 are provided at the bottom of antenna element 1. Antenna element 1 is soldered to the second groove 304 of antenna base plate 3 via these ground pads 105.

[0048] like Figure 6 As shown, the antenna protection cover 2 is designed as a circular structure, located outside the antenna element 1, and fixed in the first groove 303 of the antenna base plate 3 by gluing. The antenna protection cover 2 is made of low dielectric constant material and protects the antenna element 1 from dust.

[0049] like Figures 7 and 8As shown, the antenna base plate 3 supports and secures the antenna element 1 and the antenna protective cover 2. It includes a welding window cover 301 and two sets of coaxial structures 302. The coaxial structures 302 are 50Ω coaxial structures and are used to connect the antenna element 1 to the broadband phase-shift feed network board 4. The welding window cover 301 is fixed to the antenna base plate 3 by gluing to protect the solder joints on the broadband phase-shift feed network board 4. The back of the antenna base plate 3 reserves a recessed structure 305 for embedding and securing the broadband phase-shift feed network board 4.

[0050] In the embodiment of the present utility model, the antenna base plate 3 is located below the antenna element 1 , and a first groove 303 and a second groove 304 are reserved thereon for fixing the antenna protective cover 2 and the antenna element 1 respectively.

[0051] like Figures 9 and 10 As shown, the broadband phase-shift feed network board 4 consists of a network layer substrate 401, a microstrip feed network 402, and a network layer ground 403. The microstrip feed network 402 is printed on the front surface of the network layer substrate 401, and the network layer ground 403 is provided with metallized vias. The broadband phase-shift feed network board 4 is embedded in the sunken structure 305 and connected to the antenna element 1 via the coaxial structure 302.

[0052] In this embodiment of the utility model, the broadband phase-shifting feed network board 4 is embedded in a sunken structure beneath the antenna base plate 3. The microstrip feed network 402 employs a branch-loaded phase shifter, with two sets of shorted branches connected in parallel. This generates currents with a 90° phase difference between the two cross-element oscillators across a wide bandwidth, enabling the antenna to achieve circularly polarized radiation output. The shorted branches are between 0.1λ0 and λ0 (λ0 being the wavelength of the center frequency medium), enabling the phase-shifting feed network to achieve broadband phase stability while maintaining a small phase error (±6°) across a wide bandwidth.

[0053] like Figures 11 and 12 As shown, the network cavity 5 is tightly pressed against the broadband phase-shifted feed network board 4 and consists of a network external cavity 501, a network internal cavity 502, and a network cavity bottom plate 503. A groove structure is formed between the network external cavity 501 and the network internal cavity 502, whose shape is the same as the outer shape of the microstrip feed network 402. The network internal cavity 502 is used to isolate the microstrip feed network 402 from the network layer ground 403, thereby eliminating the resonance points generated by a single-layer network in a deep cavity. The network external cavity 501, the network internal cavity 502, and the network cavity bottom plate 503 are all connected by screws.

[0054] In the embodiment of the present invention, circular feeding holes 504 are reserved on the network external cavity 501 and the network cavity bottom plate 503 so that the RF connector can pass through the circular feeding holes 504 to connect to the broadband phase-shift feeding network 4 .

[0055] like Figure 13 As shown, the RF connector 6 is located at the bottom of the network cavity 5 and consists of an inner conductor 601, a dielectric 602 and a shell 603. The inner conductor 601 and the dielectric 602 pass through the feeding hole 504 on the network cavity 5 to form a coaxial structure, and the inner conductor 601 is welded to the microstrip feeding network 402. The shell 603 is fixed to the bottom of the reflective floor by screws to achieve good grounding.

[0056] like Figures 14 and 15 As shown, the antenna of the present invention can achieve an axial ratio of ≤2 in the full frequency band of 12GHz-18GHz, and an antenna gain ≥0dB within a 120° beam width in the azimuth plane.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiment, those skilled in the art will be able to modify the technical solutions of the aforementioned embodiment or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A Ku-band wide-bandwidth beam low-axis ratio circularly polarized antenna, characterized in that: include: Antenna element (1), antenna base plate (3), broadband phase-shifted feed network board (4), network cavity (5), radio frequency connector (6); The antenna element (1) is fixed to the front surface of the antenna base plate (3); The broadband phase-shifted feed network board (4) is embedded in the back surface of the antenna base plate (3); The network cavity (5) is fixed to the back of the antenna base plate (3) and tightly presses the broadband phase-shifted feeding network board (4); The radio frequency connector (6) is fixed to the back of the network cavity (5), passes through the network cavity (5) and is connected to the broadband phase-shift feeding network board (4), and is used to feed the entire antenna.

2. The Ku-band wide-bandwidth beam low-axis ratio circularly polarized antenna according to claim 1, characterized in that: The antenna element (1) is in the form of a cross-printed dipole, comprising two cross-shaped antenna substrates (101), with a microstrip feeding balun (102) and a microstrip printed element (103) printed on the front and back sides of each antenna substrate (101), respectively, and the element arms of the microstrip printed element (103) adopt a bent structure.

3. The Ku-band wide-bandwidth beam low-axis ratio circularly polarized antenna according to claim 2, characterized in that: The antenna substrates (101) where the microstrip printed oscillators (103) are not cut off in the two cross-shaped antenna substrates (101) are designed with metallized holes (104) for reconnecting the microstrip printed oscillators (103) cut off by the cutting seam by soldering, so that the antenna oscillator (1) is more symmetrical in structure, thereby reducing the antenna axial ratio.

4. The Ku-band wide-bandwidth beam low-axis ratio circularly polarized antenna according to claim 1, characterized in that: A groove for fixing the antenna vibrator (1) is reserved on the front side of the antenna base plate (3).

5. The Ku-band wide-bandwidth beam low-axis ratio circularly polarized antenna according to claim 1, characterized in that: The antenna base plate (3) further comprises a welding window cover plate (301) and a group of coaxial structures (302). The coaxial structures (302) are used to connect the antenna element (1) and the broadband phase-shift feed network board (4) to achieve antenna feeding. The welding window cover plate (301) protects the welding points on the broadband phase-shift feed network board (4).

6. The Ku-band wide-bandwidth beam low-axis ratio circularly polarized antenna according to claim 1, characterized in that: The broadband phase-shift feeding network board (4) comprises a network layer substrate (401), a microstrip feeding network (402) and a network layer ground (403); the microstrip feeding network (402) adopts a branch-loaded phase shifter, and two groups of open-short-circuited branches are connected in parallel, so that the broadband phase-shift feeding network board (4) achieves broadband phase stabilization and ensures a small phase error under a wide frequency band.

7. The Ku-band wide-bandwidth beam low-axis ratio circularly polarized antenna according to claim 6, characterized in that: The length of the open-short-circuit branch is between 0.1λ0 and λ0, wherein λ0 is the wavelength of the center frequency medium.

8. The Ku-band wide bandwidth beam low axial ratio circularly polarized antenna according to claim 1, characterized in that: The network cavity (5) comprises a network external cavity (501), a network internal cavity (502) and a network cavity bottom plate (503); the network internal cavity (502) isolates the microstrip feeding network (402) and the network layer ground (403) from each other, and is used to eliminate the resonance point of the broadband phase-shift feeding network board (4) in the cavity.

9. The Ku-band wide-bandwidth beam low-axis ratio circularly polarized antenna according to claim 1, characterized in that: It also includes an antenna protection cover (2) located on the outer ring of the antenna vibrator (1); the antenna protection cover (2) is fixed on the antenna base plate (3) and is used to provide dustproof protection for the antenna vibrator (1).

10. The Ku-band wide-bandwidth beam low-axis ratio circularly polarized antenna according to claim 9, characterized in that: The antenna protection cover (2) is made of a low dielectric constant material.

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