A wide-bandwidth, wide-axis ratio circularly polarized antenna for Ka-band

Abstract

This invention belongs to the field of communication antenna technology, specifically relating to a wide-bandwidth, wide-beamwidth, wide-axis-ratio circularly polarized antenna applied to the Ka-band. The invention includes: a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, a fourth dielectric substrate, and a fifth dielectric substrate; a parasitic radiating patch disposed on the top surface of the first dielectric substrate; a main radiating patch disposed between the first and second dielectric substrates; a radiating ground plane disposed between the second and third dielectric substrates; a power divider network disposed between the third and fourth dielectric substrates; a power divider network ground plane disposed on the bottom surface of the fifth dielectric substrate; and a first metal pillar, the upper end of which is electrically connected to the power divider network, and the lower end which is on the same horizontal plane as the power divider network ground plane but not electrically connected; the main radiating patch and the power divider network are electrically connected through several power divider metal pillars. This invention addresses the technical problem of performance shortcomings of existing microstrip antennas in satellite communication.

Description

Technical Field

[0001] This utility model belongs to the field of communication antenna technology, specifically relating to a Ka-band wide-bandwidth beamwidth wide-axis ratio circularly polarized antenna. Background Technology

[0002] With the development of mobile communications, satellite communications are playing an increasingly important role in our lives. They offer significant advantages over other communication methods in terms of communication distance, coverage, cost, signal capacity, and security. To ensure that mobile communication terminals can quickly complete positioning and communication functions in various orientations, satellite communication equipment places higher demands on antenna specifications such as beamwidth, polarization, operating bandwidth, and profile height. Generally, antennas are required to have wide-bandwidth coverage, ensuring minimal gain attenuation when the phased array scans at large angles. Simultaneously, they should possess circular polarization and a wide axial ratio to guarantee effective reception in complex environments.

[0003] Traditional quad-arm helical antennas have a wide beamwidth, but their high profile, narrow bandwidth, complex feeding network, and difficulty in controlling manufacturing precision limit their application in mobile communication terminals. On the other hand, microstrip antennas, due to their low profile, small size, conformal design, ease of fabrication, low cost, and diverse feeding methods and polarization forms, are widely used in mobile satellite communication systems.

[0004] Traditional microstrip antennas have a narrow operating bandwidth of less than 5% and a limited beamwidth, typically around 80° at half power within the band. Some designs employ a slot-coupled feeding dual-layer structure to achieve a wider operating bandwidth, but the beamwidth remains limited. Others combine microstrip antennas with parallel dipole radiation modes to obtain a wider beamwidth, but the bandwidth is still narrow. Therefore, how to broaden the operating bandwidth and achieve wide beam coverage and good circular polarization performance within the broadband range remains a key research focus for the application of microstrip antennas in satellite communication terminals. Utility Model Content

[0005] This invention provides a wide-bandwidth, wide-beamwidth, wide-axis-ratio circularly polarized antenna for the Ka-band, which addresses the technical problem of performance shortcomings of existing microstrip antennas in satellite communications.

[0006] This utility model includes: a five-layer dielectric substrate, namely a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, a fourth dielectric substrate and a fifth dielectric substrate stacked from top to bottom;

[0007] A parasitic radiation patch is disposed on the top surface of the first dielectric substrate;

[0008] The main radiating patch is disposed between the first dielectric substrate and the second dielectric substrate;

[0009] A radiant floor is disposed between the second dielectric substrate and the third dielectric substrate;

[0010] A power distribution network is disposed between the third dielectric substrate and the fourth dielectric substrate;

[0011] The power distribution network ground plane is disposed on the bottom surface of the fifth dielectric substrate;

[0012] A first metal pillar passes through the fourth dielectric substrate and the fifth dielectric substrate. Its upper end is electrically connected to the power distribution network, and its lower end is on the same horizontal plane as the power distribution network floor and is not electrically connected.

[0013] The main radiating patch is electrically connected to the power distribution network via a plurality of power feeding metal pillars, and the power feeding metal pillars pass through the radiating floor.

[0014] The four corners of both the main radiating patch and the parasitic radiating patch are cross-shaped, and their positions correspond to each other.

[0015] This invention extends the operating bandwidth through a dual-layer microstrip coupling of parasitic radiating patches and main radiating patches, and improves circular polarization performance through a power distribution network.

[0016] Furthermore, a square metal ring is also provided on the top surface of the first dielectric substrate;

[0017] The square metal ring is fitted over the parasitic radiation patch;

[0018] Several metal strips are also evenly distributed between the square metal ring and the parasitic radiation patch;

[0019] The metal strip is electrically connected to the radiant floor via a second metal post. The beneficial effect of this step is to further widen the beamwidth.

[0020] Further: the plurality of said metal strips include:

[0021] Four right-angled rectangular metal strips are evenly distributed at the four corners of the parasitic radiation patch, with the apex of each right-angled rectangular metal strip facing the corner.

[0022] Eight rectangular metal strips are evenly distributed around the parasitic radiation patch, with every two rectangular metal strips sandwiched between the right-angled rectangular metal strips;

[0023] The sum of the length of the second metal pillar and the length of the metal strip is equal to one-quarter of the dielectric wavelength corresponding to the center frequency. The beneficial effects of this step are: to achieve resonance within the working frequency band, to excite its conical radiation pattern on the XOY plane, and to supplement the low elevation gain of the microstrip antenna.

[0024] Furthermore: the power distribution network includes:

[0025] A T-junction, one end of which is electrically connected to the first metal post;

[0026] Two Wilkinson power dividers are connected to the other two ends of the T-junction, respectively. The four feed metal pillars on the two Wilkinson power dividers are distributed with a 90° phase difference. The beneficial effect of this step is that it ensures the antenna's excellent circular polarization performance and achieves a wider axial ratio bandwidth.

[0027] Furthermore: the first dielectric substrate, the third dielectric substrate, and the fifth dielectric substrate are dielectric core boards, and the second dielectric substrate and the fourth dielectric substrate are prepregs. The beneficial effects of this step are: small overall size and low profile.

[0028] The beneficial effects of this utility model are:

[0029] 1. In the Ka band of satellite communication, the antenna size is 5×5×1.25mm, which has the advantages of small size, low profile and easy integration;

[0030] 2. With a relative bandwidth of over 18% and a VSWR of less than 1.8, it can achieve a wide beamwidth (half-power beamwidth exceeding 140°) over a wide frequency band. Simultaneously, the gain at theta=60° is between 0-1.5dBi, the in-band normal axial ratio is less than 0.1, and the beamwidth is greater than 100° for axial ratios less than 3. All of these are superior to conventional microstrip patch antennas. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 A three-dimensional view of a Ka-band wide-bandwidth beamwidth wide-axis ratio circularly polarized antenna provided by this utility model;

[0033] Figure 2 A top view of a Ka-band wide-bandwidth beamwidth wide-axis ratio circularly polarized antenna provided by this utility model;

[0034] Figure 3 A schematic diagram of the power divider network for use in a Ka-band wide-bandwidth beamwidth wide-axis ratio circularly polarized antenna provided by this utility model;

[0035] Figure 4 An exploded view of a Ka-band wide-bandwidth beamwidth wide-axis ratio circularly polarized antenna provided by this utility model;

[0036] Figure 5 A side view of a Ka-band wide-bandwidth beamwidth wide-axis ratio circularly polarized antenna provided by this utility model;

[0037] Figure 6 The present invention provides a standing wave frequency response curve for a Ka-band wide bandwidth beamwidth wide axial ratio circularly polarized antenna.

[0038] Figure 7 The present invention provides a frequency response curve of normal gain and 60° scanning gain for a Ka-band wide-bandwidth beamwidth wide-axis ratio circularly polarized antenna.

[0039] Figure 8 This invention provides an in-band frequency radiation pattern for a Ka-band wide-bandwidth beamwidth wide-axis ratio circularly polarized antenna.

[0040] Figure 9 The present invention provides a normal axial ratio frequency response curve for a Ka-band wide-bandwidth beamwidth wide-axis ratio circularly polarized antenna.

[0041] Figure 10 This invention provides a center frequency section axial ratio beamwidth curve for a Ka-band wide bandwidth beamwidth wide axial ratio circularly polarized antenna.

[0042] Figure label:

[0043] 100 - First dielectric substrate; 101 - Second dielectric substrate; 102 - Third dielectric substrate; 103 - Fourth dielectric substrate; 104 - Fifth dielectric substrate; 200 - Square metal ring; 201 - Right-angled rectangular metal strip; 202 - Rectangular metal strip; 203 - Second metal pillar; 300 - Parasitic radiating patch; 301 - Main radiating patch; 302 - Feeding metal pillar; 400 - Feeding power divider network; 401 - First metal pillar; 402 - Wilkinson power divider; 404 - T-junction; 500 - Spacing; 501 - Chamfered corner. Detailed Implementation

[0044] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0045] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application shall have the ordinary meaning as understood by one of ordinary skill in the art to which this utility model pertains.

[0046] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0047] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly defined.

[0048] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0049] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0050] This application implements, for example Figures 1-5As shown, this application provides a wide-bandwidth, wide-axis-ratio circularly polarized antenna for the Ka-band.

[0051] This application includes: a five-layer dielectric substrate, namely a first dielectric substrate 100, a second dielectric substrate 101, a third dielectric substrate 102, a fourth dielectric substrate 103 and a fifth dielectric substrate 104 stacked from top to bottom;

[0052] Parasitic radiation patch 300 is disposed on the top surface of the first dielectric substrate 100;

[0053] The main radiating patch 301 is disposed between the first dielectric substrate 100 and the second dielectric substrate 101;

[0054] A radiant floor is disposed between the second dielectric substrate 101 and the third dielectric substrate 102;

[0055] A power distribution network 400 is disposed between the third dielectric substrate 102 and the fourth dielectric substrate 103;

[0056] The power distribution network ground plane is disposed on the bottom surface of the fifth dielectric substrate 104;

[0057] The first metal pillar 401 passes through the fourth dielectric substrate 103 and the fifth dielectric substrate 104. Its upper end is electrically connected to the power distribution network 400, and its lower end is on the same horizontal plane as the power distribution network floor and is not electrically connected.

[0058] The main radiating patch 301 is electrically connected to the power distribution network 400 through a plurality of power feeding metal pillars 302, and the power feeding metal pillars 302 pass through the radiating floor.

[0059] The four apex corners of the main radiating patch 301 and the parasitic radiating patch 300 are all cross-shaped, and their positions correspond to each other.

[0060] There is no conductive material such as copper between the fourth dielectric substrate 103 and the fifth dielectric substrate 104; the thickness of the first dielectric substrate 100 is 0.4 mm, the thickness of the second dielectric substrate 101 is 0.3 mm, the thickness of the third dielectric substrate 102 is 0.15 mm, the thickness of the fourth dielectric substrate 103 is 0.1 mm, and the thickness of the fifth dielectric substrate 104 is 0.3 mm.

[0061] This application extends the operating bandwidth through a dual-layer microstrip coupling of parasitic radiating patch 300 and main radiating patch 301, and achieves wide beam coverage and good circular polarization performance in the broadband through a power distribution network 400, in order to meet the new antenna requirements of Ka-band satellite mobile communication terminals.

[0062] The power divider network 400 and the power divider network ground plane cannot be on the same layer, otherwise the power divider network cannot provide power. In the actual manufacturing process, a quasi-coaxial structure is made around the first metal pillar 401 of the power divider (with an annular gap between the power divider network ground plane and the first metal pillar 401), which is welded to the external RF connector. The first metal pillar 401 is connected to the inner core of the RF connector, and the power divider network ground plane is connected to the outer sheath of the RF connector. Only in this way can the RF connector be properly connected to the cable.

[0063] If the power distribution network 400 and the power distribution network ground plane are on the same layer, this quasi-coaxial structure cannot be formed. At the same time, the power distribution network 400 will be exposed from the inside of the structure to the surface, making it susceptible to the influence of the external electromagnetic environment and deterioration.

[0064] Based on the above technical solution, a square metal ring 200 is also provided on the top surface of the first dielectric substrate 100.

[0065] The square metal ring 200 is fitted over the parasitic radiation patch 300;

[0066] Several metal strips are also evenly distributed between the square metal ring 200 and the parasitic radiation patch 300;

[0067] The metal strip is electrically connected to the radiating ground via the second metal post 203. The metal strip can serve as a folded dipole structure, which can excite a conical radiation pattern when the antenna is working. This pattern complements the radiation patterns of the microstrip patch (main radiating patch 301 and parasitic radiating patch 300), further expanding the beamwidth of the antenna. Combined with the square metal ring 200, the beamwidth is further widened.

[0068] Based on the above technical solution, several of the metal strips include:

[0069] Four right-angled rectangular metal strips 201 are evenly distributed at the four chamfered corners 501 of the parasitic radiation patch 300, and the apex of the right-angled rectangular metal strips 201 faces the chamfered corner 501.

[0070] Eight rectangular metal strips 202 are evenly distributed around the parasitic radiation patch 300, and every two rectangular metal strips 202 are sandwiched between the right-angled rectangular metal strips 201.

[0071] The sum of the length of the second metal pillar 203 and the length of the metal strip is equal to one-quarter of the dielectric wavelength corresponding to the center frequency, achieving resonance within the operating frequency band and exciting its conical radiation pattern on the XOY plane to supplement the low elevation gain of the microstrip antenna. Furthermore, the distance 500 between the metal strip and the parasitic radiating patch 300 is 0.3 mm, and this distance directly affects the beamwidth. The rectangular chamfers 501 around the main radiating patch 301 and the parasitic radiating patch 300, with each chamfer 501 having a side length approximately 20% of its own side length, prevent interference between the patch and the folded dipole structure, resulting in a more compact overall structure.

[0072] Based on the above technical solution, the power distribution network 400 includes:

[0073] A T-junction 404, one end of which is electrically connected to the first metal post 401;

[0074] Two Wilkinson power dividers 402 are connected to the other two ends of the T-junction 404, respectively. The four feed metal posts 302 on the two Wilkinson power dividers 402 are distributed with a 90° phase difference, outputting four equal-amplitude signals with a sequential 90° phase difference. These signals directly feed the main radiating patch 301 through the feed metal posts 302. The four-feed configuration ensures excellent circular polarization performance of the antenna and achieves a wide axial ratio bandwidth. The entire network structure is compact and integrated inside the antenna. The feed power divider network 400 ends through the first metal post 401 as the feed input port, leading out the feed power divider network ground plane.

[0075] Based on the above technical solution, the first dielectric substrate 100, the third dielectric substrate 102 and the fifth dielectric substrate 104 are dielectric core boards, and the second dielectric substrate 101 and the fourth dielectric substrate 103 are prepregs. The dielectric core board uses the R5775(N) model from the Panasonic Electric Works Megtron 6 series, and the prepreg uses the R5670(N) model from the Panasonic Electric Works Megtron 6 series. It has good dielectric properties, and the antenna size is 5×5×1.25mm, with a small overall size and low profile.

[0076] As described above, the antenna consists of a five-layer dielectric substrate. From top to bottom, it comprises a parasitic radiating patch 300, folded monopole structures (metal strips) around the parasitic radiating patch 300 to extend the beamwidth, a square metal ring 200, a main radiating patch 301, feeding metal pillars 302, and a four-output stripline feeding power divider network 400 with equal amplitude and equal 90° phase difference. During operation, the antenna is fed from the bottom feed port to the feeding power divider network 400. This power divider network (1 to 4) and the four feeding metal pillars 302 excite the main radiating patch 301 to form circular polarization, while simultaneously coupling power to the parasitic radiating patch 300. The folded monopole structures (metal strips) around the perimeter generate induced current through the radiating ground plane, forming a cone-shaped radiation pattern that complements the wide-side radiation pattern formed by the main radiating patch 301 and the parasitic radiating patch 300, thus creating a wide beamwidth. This antenna operates in the Ka band, meeting the gain requirements for low elevation angles, and also features wideband circular polarization, making it suitable for low-Earth orbit satellite communication systems.

[0077] The specific performance of this antenna is as follows: Figures 6-10 As shown, Figure 6 The antenna's standing wave ratio is less than 1.8. Figure 7 The scan gain at theta=60° is between 0-1.5 dBi. Figure 8 The display shows a half-power beamwidth of over 140°. Figure 9 The display shows that the normal axis ratio within the band is less than 0.1. Figure 10 The display shows that under the conditions of phi=0°, 45°, and 90°, the beamwidth of beams with an axial ratio of less than 3 is greater than 100°;

[0078] Numerous specific details are set forth in this specification. However, it will be understood that embodiments of this invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification. In the description of this specification, references to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A wide-bandwidth, wide-axis-ratio circularly polarized antenna for the Ka-band, characterized in that, include: The five dielectric substrates are, from top to bottom, the first dielectric substrate, the second dielectric substrate, the third dielectric substrate, the fourth dielectric substrate, and the fifth dielectric substrate; A parasitic radiation patch is disposed on the top surface of the first dielectric substrate; The main radiating patch is disposed between the first dielectric substrate and the second dielectric substrate; A radiant floor is disposed between the second dielectric substrate and the third dielectric substrate; A power distribution network is disposed between the third dielectric substrate and the fourth dielectric substrate; The power distribution network ground plane is disposed on the bottom surface of the fifth dielectric substrate; A first metal pillar passes through the fourth dielectric substrate and the fifth dielectric substrate. Its upper end is electrically connected to the power distribution network, and its lower end is on the same horizontal plane as the power distribution network floor and is not electrically connected. The main radiating patch is electrically connected to the power distribution network via a plurality of power feeding metal pillars, and the power feeding metal pillars pass through the radiating floor. The four corners of both the main radiating patch and the parasitic radiating patch are cross-shaped, and their positions correspond to each other.

2. The Ka-band wide-bandwidth beamwidth wide-axis ratio circularly polarized antenna according to claim 1, characterized in that, The top surface of the first dielectric substrate is also provided with a square metal ring; The square metal ring is fitted over the parasitic radiation patch; Several metal strips are also evenly distributed between the square metal ring and the parasitic radiation patch; The metal strip is electrically connected to the radiant floor via a second metal post.

3. The Ka-band wide-bandwidth beamwidth wide-axis ratio circularly polarized antenna according to claim 2, characterized in that, The plurality of said metal strips include: Four right-angled rectangular metal strips are evenly distributed at the four corners of the parasitic radiation patch, with the apex of each right-angled rectangular metal strip facing the corner. Eight rectangular metal strips are evenly distributed around the parasitic radiation patch, with every two rectangular metal strips sandwiched between the right-angled rectangular metal strips; The sum of the length of the second metal column and the length of the metal strip is equal to one-quarter of the dielectric wavelength corresponding to the center frequency.

4. The Ka-band wide-bandwidth beamwidth wide-axis ratio circularly polarized antenna according to claim 1, characterized in that, The power distribution network includes: A T-junction, one end of which is electrically connected to the first metal post; Two Wilkinson power dividers are connected to the other two ends of the T-junction, and the four feed metal pillars on the two Wilkinson power dividers are distributed with a 90° phase difference.

5. The Ka-band wide-bandwidth beamwidth wide-axis ratio circularly polarized antenna according to claim 1, characterized in that, The first dielectric substrate, the third dielectric substrate, and the fifth dielectric substrate are dielectric core boards, and the second dielectric substrate and the fourth dielectric substrate are prepregs.

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