Miniaturized sea surface positioning information receiving device

Abstract

The invention belongs to the related field of communication devices, and discloses a miniaturized sea surface positioning information receiving device, the main body structure of the miniaturized sea surface positioning information receiving device is in a shape formed by combining a cylindrical cavity and a circular truncated cone, and the miniaturized sea surface positioning information receiving device comprises functional elements such as a radiation unit, an impedance matching element and a feed element; wherein the radiation unit is provided with three groups of parallel X-shaped gaps which are sequentially arranged on the cavity wall of the cylindrical cavity along the axial direction; and the impedance matching element is formed by jointly connecting three sections of cylinders with different diameters, and is coaxially arranged in the cylindrical cavity. Further, a power feeding element is mounted inside the truncated cone body, and it has a truncated cone shape that remains coaxial with the impedance matching element. According to the invention, the antenna has a plurality of resonance points in a fixed frequency range, multi-band coverage is realized, good impedance matching between the antenna array and the external environment is ensured, reflection power is reduced to the greatest extent, and good radiation characteristics can still be maintained under the condition that a waterproof cover is added.

Description

Technical Field

[0001] The present invention belongs to the field of communication devices, and more specifically, relates to a miniaturized sea surface positioning information receiving device. Background Art

[0002] In recent years, with the rapid development of satellite communication global positioning system (GPS) and Beidou navigation system (BDstart), the application fields are becoming more and more extensive. Antenna, as a component for receiving and transmitting electromagnetic waves in satellite communication, plays a vital role in the entire satellite system.

[0003] The L-band is widely used in DAB (digital audio broadcasting) and satellite navigation systems in satellite communications. These systems rely on the stability and reliability of the L-band to achieve efficient data transmission and navigation and positioning functions. Circularly polarized antennas are currently the mainstream L-band satellite antennas. They are widely used in satellites and other fields due to their good orthogonality, excellent anti-multipath interference capabilities, and wide signal coverage. Since the 1960s and 1970s, a large number of researchers have adopted new materials and new architectures to achieve better circular polarization, and a variety of circularly polarized satellite antennas have been derived.

[0004] Omnidirectional circularly polarized antennas can transmit and receive signals evenly in all directions, thus providing a wide signal coverage range, which gives it a significant advantage in scenarios that require all-round communication (such as satellite communications, remote sensing and telemetry, etc.). At the same time, when it is used as a receiving antenna, it can receive electromagnetic waves in any polarization form, thus avoiding energy loss caused by polarization mismatch. This feature makes the omnidirectional circularly polarized antenna more efficient and reliable when receiving signals from different directions and different polarization states. In addition, it also has the advantages of suppressing multipath interference and resisting Faraday rotation effect.

[0005] However, further research shows that when omnidirectional circularly polarized antennas are applied to specific occasions such as marine communications, they still have the following defects or shortcomings:

[0006] First, the omnidirectional circularly polarized antenna in the prior art can usually only work in a specific frequency band, which limits its communication flexibility; and because the single-band antenna only supports one frequency band, when the communication frequency band changes, the antenna may need to be replaced (such as frequency band adjustment, spectrum reallocation, etc.), which increases maintenance costs and operational complexity;

[0007] Secondly, omnidirectional antennas radiate signals evenly in all directions, which results in relatively low gain in a specific direction. In contrast, directional antennas can focus energy in a specific direction, thus providing higher gain. Accordingly, in specific scenarios that require long-distance communication or high-speed data transmission, omnidirectional antennas in the prior art cannot achieve the desired working performance.

[0008] Finally, considering that when used in a marine environment, the omnidirectional antenna may be immersed in seawater and is usually equipped with a waterproof cover, which causes its radiation characteristics to be weakened in the water-air cross-medium space. The omnidirectional antenna in the existing technology lacks an effective solution to this problem. Summary of the invention

[0009] In response to one or more of the above defects or needs of the prior art, the present invention provides a miniaturized sea surface positioning information receiving device, which fully combines the working characteristics and specific needs of the communication antenna in the marine environment, and re-studies and improves its overall structural composition, key design parameters and working mechanism. It not only enables the antenna to have multiple resonance points within a fixed frequency range to achieve multi-band coverage, but also ensures that the antenna array has good impedance matching with the external environment, minimizes the reflected power, and can still maintain good radiation characteristics when a waterproof cover is added. Therefore, it is particularly suitable for applications such as sea surface positioning information reception.

[0010] To achieve the above object, according to the present invention, a miniaturized sea surface positioning information receiving device is provided, characterized in that the device has a main structure composed of a cylindrical cavity and a truncated cone, and constitutes a circularly polarized omnidirectional antenna including a radiation unit, an impedance matching element and a feeding element, wherein:

[0011] The radiation unit has three groups of parallel X-shaped slots, which are sequentially opened on the cavity wall of the cylindrical cavity along the axial direction, and the interior of the cylindrical cavity is correspondingly provided with a filling section made of dielectric material; wherein the center distance between the first group of X-shaped slots located at the tail end of the antenna and the second group of X-shaped slots adjacent thereto is set to be smaller than the center distance between the second group of X-shaped slots and the third group of X-shaped slots located at the head end of the antenna;

[0012] The impedance matching element is formed by connecting three sections of cylinders with different diameters, which are coaxially installed inside the cylindrical cavity of the main structure, and are used to match the feeding element with the filling section composed of the dielectric material; wherein the diameters of the three sections of coaxially installed cylinders are gradually increased between the filling section and the feeding element;

[0013] The feeding element is installed inside the frustum of the main structure and is in a frustum cone shape coaxial with the impedance matching element.

[0014] As a further preferred embodiment of the present invention, for the radiation unit, two slots in each group of the X-shaped slots are perpendicular to each other and have a phase difference of 90°.

[0015] As a further preferred embodiment of the present invention, for the radiation unit, each group of the X-shaped slots is preferably arranged at an angle interval of β / 4 along the cylindrical center of the main structure, wherein β represents a medium wavelength.

[0016] As a further preferred embodiment of the present invention, for the radiation unit, the length H of each slot in each group of the X-shaped slots is preferably designed to be Where β represents the medium wavelength.

[0017] As a further preferred embodiment of the present invention, for the impedance matching element, the diameter ratio of the three coaxially mounted cylinders is preferably designed to be 7:9:11.

[0018] As a further preferred embodiment of the present invention, for the impedance matching element, the length ratio of the three sections of coaxially mounted cylinders is preferably designed to be 1:1:1.

[0019] As a further preferred embodiment of the present invention, for the feeding element, the diameter ratio of the upper and lower bottom surfaces thereof is preferably designed to be equal to the ratio of the minimum diameter to the maximum diameter of the main body structure.

[0020] As a further preference of the present invention, the above-mentioned miniaturized sea surface positioning information receiving device is preferably used as an L-band satellite antenna of the Beidou navigation system.

[0021] In general, the above technical solution conceived by the present invention has the following technical advantages compared with the prior art:

[0022] (1) The present invention has re-studied and improved the overall structure and key design parameters of the dual-frequency circularly polarized antenna. The circular waveguide resonant cavity is used to radiate electromagnetic waves and an X-shaped slot is used to achieve coupling, so that the antenna has multiple resonance points within a fixed frequency range. The spacing between the slot pairs and the size of the tapered coaxial matching section can be adjusted to ensure that the antenna can work normally in both the uplink and downlink of the L-band satellite, thereby achieving multi-channel coverage.

[0023] (2) The present invention can better play the role of matching the load by designing the spacing between the first group of X-shaped slots and the second group of X-shaped slots to be smaller than the spacing between the second group of X-shaped slots and the third group of X-shaped slots. On the basis of radiating electromagnetic wave band, the reflected wave at the shortened end of the coaxial cylinder is eliminated, the gain of the antenna is improved, and the traveling wave structure of the antenna is maintained. Therefore, the present invention has a lower axial ratio within a fixed frequency band and can maintain a stable high gain;

[0024] (3) The present invention designs three sections of coaxial impedance matching with different diameters and increasing section by section, so that the antenna array can have good impedance matching with the external environment, minimize the reflected power, and improve the energy utilization rate. Correspondingly, even in harsh working conditions such as marine communications, it can effectively reduce the loss in the signal transmission process and improve the system performance;

[0025] (4) The feeding element of the present invention adopts cylindrical center feeding at the end, and the diameter of the cylinder is small, which is convenient for forming an antenna array and further improving the gain and beam width of the antenna; in addition, since the radiation cavity of the present invention is cylindrical, its omnidirectional radiation capability is greatly enhanced. Under the premise of having good waterproof performance, the antenna is equivalent to a directional satellite communication antenna on the sea surface, and a better beam width can be achieved by adjusting the immersion depth of its buoy;

[0026] (5) The dual-frequency circularly polarized antenna of the present invention has the advantages of compact structure and easy operation, and is easy to couple and feed without components such as inductors and capacitors. The subsequent debugging of the antenna is also simpler and has lower costs. It is suitable for large-scale production. Therefore, it is particularly suitable as a sea surface positioning information receiving device and for L-band satellite communication occasions of the Beidou navigation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall appearance of the miniaturized sea surface positioning information receiving device provided by the present application;

[0028] Figure 2 yes Figure 1 A schematic diagram of the arrangement and dimensions of the multiple functional components shown in ;

[0029] Figure 3 It is a schematic diagram of the size design of the X-shaped gap according to the preferred embodiment of the present application;

[0030] Figure 4 It is a schematic diagram of the size design of the feeding element according to the preferred embodiment of the present application;

[0031] Figure 5 is the S of the antenna according to the specific embodiment 1 of the present application 11 Reflection coefficient diagram;

[0032] Figure 6a , 6b They are respectively the E-plane and H-plane gain curves of the antenna at 1.62 GHz and 2.49 GHz according to the specific embodiment 1 of the present application;

[0033] Figure 7 It is the left-hand circular polarization and right-hand circular polarization gain diagram of the antenna at 1.62 GHz and 2.49 GHz according to the specific embodiment 1 of the present application;

[0034] Figure 8 is a schematic diagram showing the change of gain and axial ratio of the antenna over time according to specific embodiment 1 of the present application;

[0035] Fig. 9 It is a schematic diagram of the variation of skin depth of the antenna in the 1.5-2.5 GHz frequency band with frequency according to the specific embodiment 1 of the present application;

[0036] Fig.10 is the reflection coefficient S of the antenna at three depths according to the specific embodiment of the present application 11 Schematic diagram. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0038] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations or constituent elements, and do not limit one or more additional functions, operations and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components or combinations thereof.

[0039] It should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0041] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] Figure 1 is a schematic diagram of the overall appearance of a miniaturized sea surface positioning information receiving device provided by the present application. Figure 2 yes Figure 1 The arrangement and size diagram of multiple functional components shown in FIG. Figure 1 and Figure 2 To explain the present invention in more detail.

[0043] Reference Figure 1 and Figure 2 The miniaturized sea surface positioning information receiving device has a main structure composed of a cylindrical cavity and a truncated cone, and constitutes a circularly polarized omnidirectional antenna used as an L-band satellite antenna, mainly including functional elements such as a radiation unit, an impedance matching element and a feeding element.

[0044] The radiation unit has three groups of parallel X-shaped slots, which are sequentially opened on the cavity wall of the cylindrical cavity along the axial direction, and a filling section composed of dielectric material is correspondingly arranged inside the cylindrical cavity; wherein the spacing between the first group of X-shaped slots located at the tail end of the antenna and the second group of X-shaped slots adjacent thereto is set to be smaller than the spacing between the second group of X-shaped slots and the third group of X-shaped slots located at the head end of the antenna; the impedance matching element is formed by connecting three sections of cylinders with different diameters, which are coaxially installed inside the cylindrical cavity of the main structure, and are used to match and install the feeding element with the filling section composed of dielectric material; wherein the three sections of coaxially installed cylinders are in a variation form of gradually increasing diameter between the filling section and the feeding element; the feeding element is installed inside the truncated cone body of the main structure, and it is in a truncated cone shape coaxial with the impedance matching element.

[0045] More specifically, if Figure 1 and Figure 2As shown in , the diameter of the cylindrical cavity of the main structure is W1; the wall thickness of the antenna is, for example, 1.5 mm, wherein the radiation units are composed of four groups of two pairs of parallel "X"-shaped slots distributed along the axial direction, and the two slots of the "X"-shaped slots are equal. In addition, the interior of the cylindrical cavity may be provided with an internal filler such as polyethylene, whose dielectric constant ε=2.1. Polyethylene, as a reinforcing fiber with good dielectric properties, can enhance the dielectric properties of the antenna, reduce signal loss, improve the efficiency of the antenna, and enhance the structure of the antenna. In this way, by filling with dielectric materials such as polyethylene, the length of the slot can be further reduced (the actual slot length of the antenna is 0.8 of the theoretical length), which correspondingly reduces the cost of the antenna while making the structure compact.

[0046] In order to better realize the omnidirectional radiation of the antenna, the two slots in each group of the X-shaped slots are perpendicular to each other and have a phase difference of 90°. In addition, for the radiating unit, the X-shaped slots in each group are preferably arranged at an angle interval of β / 4 along the cylindrical center of the main structure, where β represents the medium wavelength; the length H of each slot in each group of the X-shaped slots is preferably designed to be Where β represents the medium wavelength.

[0047] Also see Figure 3 , H represents the length of each slot, W represents the width of each slot, H1 represents the distance between the first group of X-shaped slots at the tail end of the antenna and the edge of the cylindrical cavity, H2 represents the center distance between the first group of X-shaped slots and the adjacent second group of X-shaped slots, H3 represents the center distance between the second group of X-shaped slots and the adjacent third group of X-shaped slots, H4 represents the half length of the third group of X-shaped slots, H5 represents the distance between the third group of X-shaped slots and the coaxial edge of the impedance matching element, H6, H7 and H8 represent the lengths of the three coaxial cylinders of the impedance matching element, and H9 represents the length of the feeding element. In addition, L1 represents the diameter of the cylindrical cavity, and L2, L3 and L4 represent the diameters of the three coaxial cylinders of the impedance matching element.

[0048] In the present application, H2 is set to be smaller than H3 (for example, the fixed difference between the two is 10 mm). The purpose of this design is to play the role of matching the load, eliminate the reflected wave at the shortened end of the coaxial cylinder on the basis of the radiation electromagnetic band, improve the gain of the antenna, and maintain the traveling wave structure of the antenna. Therefore, the antenna has a lower axial ratio and maintains a stable high gain within a fixed frequency band.

[0049] As another key improvement of the present application, the present application adopts a gradient coaxial to design the impedance matching element, so that on the basis of conformity with the cavity, the reflection and loss of the signal during transmission can be reduced to achieve a better matching effect. During the transmission of the coaxial line, if the impedance of the coaxial line is inconsistent with the impedance of the signal source or the load, reflection will occur, resulting in signal attenuation and distortion. Gradient impedance matching gradually changes the parameters of the coaxial line to gradually transition the impedance, thereby avoiding the occurrence of reflection.

[0050] According to a preferred embodiment of the present application, for the impedance matching element, the diameter ratio of the three sections of coaxially mounted cylinders is preferably designed to be 7:9:11, and the length ratio thereof is preferably designed to be 1:1:1.

[0051] According to another preferred embodiment of the present application, for the feeding element, the diameter ratio of the upper and lower bottom surfaces thereof is preferably designed to be equal to the ratio of the minimum diameter to the maximum diameter of the main structure.

[0052] Also see Figure 4 The diameter ratio of the upper and lower bottom surfaces of the feeding element is preferably designed to be equal to the ratio of the minimum diameter to the maximum diameter of the main structure (i.e. ), in this way, a small-sized feeding port can be connected to a larger matching section while ensuring that the impedance remains unchanged, thereby reducing the loss caused by the sudden change in size.

[0053] The design principle of this application will be explained in more detail below.

[0054] It is easy for technicians in this field to know that in the low frequency band, a concentrated parameter inductor (L) and capacitor (C) can be used to form a resonant circuit. When the frequency increases, when the line length of the resonant circuit is comparable to the wavelength of the electromagnetic wave, energy radiation will be generated. The shorter the wavelength, the more serious the radiation, and the loss of the conductor also increases sharply, reducing the Q value of the resonant circuit.

[0055] In view of the above technical problems, the electromagnetic waves can be gathered in a medium with a high dielectric constant to solve this problem well, and its impedance matching network is more stable and reliable. In this application, a microwave resonant cavity is formed by enclosing the electromagnetic waves in a cylindrical metal cavity. Compared with the rectangular waveguide, the circular waveguide has the characteristics of low transmission loss and high mode purity, and is more suitable for use as a radiation cavity of an omnidirectional antenna; at the same time, this application also makes corresponding targeted optimizations to the design parameters of the X-shaped slot and its three impedance matching sections, so that it has multiple resonant frequencies at 1.5-2.5GHz, and then fine-tunes its resonance point to the ideal frequency band.

[0056] In addition, in the present application, the physical size of the gap is shortened by filling a dielectric material such as polyethylene, which can further reduce the overall size of the antenna and reduce the cost of the antenna to a certain extent. The present application also calculates the skin depth at 1.5GHz-2.5GHz by the skin formula, and simulates it by electromagnetic software HFSS when immersed in seawater at 1 / 4H, 1 / 2H and 3 / 4H (H represents the diameter of the circular waveguide. The experiment shows that the antenna still has good radiation characteristics in the cross-medium space of water and air when a waterproof cover is added.

[0057] Example 1

[0058] The following is a specific embodiment of the antenna optimization design parameters obtained after multiple comparison tests. The antenna can achieve the best performance by continuously optimizing the spacing between the slot pairs and the length and width of the slots, wherein the units of the data in Table 1 are all mm.

[0059] H 73mm W 11mm H1 40mm W1 42.4mm H2 65mm W2 12.4mm H3 75mm L1 11mm H4 26.5mm L2 7mm H5 15.5mm L3 9mm H6 6mm L4 11mm H7 6mm L5 16mm H8 6mm L6 4.68mm

[0060] Table 1

[0061] After various tests were performed on the antenna of the above specific embodiment 1, the results are as follows.

[0062] See also Figure 5 From the figure, we can find that the antenna S11 is less than -10dB at 1.56-1.68GHz, 1.83-2.00GHz and 2.36-2.495GHz, which basically covers the uplink frequency of 1.610-1.626GHz and the downlink frequency of 2.483GHz-2.500GHz of the L-band Beidou-1 system respectively. The antenna transmission efficiency reaches more than 90%, which can meet the basic functions of satellite reception and transmission.

[0063] See also Figure 6a and 6b In order to more intuitively observe the radiation performance of the antenna in two frequency bands, the center frequencies of 1.62 GHz and 2.49 GHz are taken in HFSS respectively. Figure 6a and 6b The E-plane and H-plane gain curves of the omnidirectional CP antenna at 1.62 GHz and 2.49 GHz are shown in the figure. It can be seen from the figure that the out-of-roundness of the antenna is less than 1.5 dB, which can meet the design requirements.

[0064] See also Figure 7 From the figure, it can be seen that the gain of the antenna at around 1.62GHz and 2.49GHz is greater than 3.89dBic, and the maximum gain is 5.06dBic; the axial ratio of the antenna at 1.62GHz is less than 2dB, and the axial ratio at 2.49GHz is equal to 3dB, which meets the design requirements of circular polarization.

[0065] See also Figure 8 From the figure, we can see that the antenna gain is greater than 3.89dBic at around 1.62GHz and 2.49GHz, and the maximum gain is 7.24dBic. Thanks to the parameter optimization of the three coaxial matching sections and three sets of "X"-shaped slots, its maximum gain value is much greater than other omnidirectional antennas on the market (generally the gain is 0-5dBic); the axial ratio of the antenna at 1.62GHz is less than 2dB, and the axial ratio at 2.49GHz is equal to 3dB, which meets the basic requirements of circular polarization.

[0066] The seawater-air cross-media simulation test results are also given below.

[0067] In actual simulation, seawater is discussed as a uniform and non-uniform medium. This simulation is calculated based on the conductivity of uniform seawater, that is, the conductivity is 4S / m. Since seawater is a conductive medium, it will produce a large energy loss in water-air transmission. Since seawater is a good conductor, electromagnetic waves decay quickly underwater. The skin depth represents the transmission distance of electromagnetic waves when the amplitude of the electromagnetic wave decays to 1 / e of the surface amplitude.

[0068] Fig. 9 The variation of skin depth of electromagnetic waves in the 1.5-2.5GHz frequency band in seawater with frequency is given. As can be seen from the figure, the maximum skin depth in the 1.5-2.5GHz frequency band is less than 12mm. In the HFSS simulation, a rectangle with a height of 12mm+0.25W1, 12mm+0.5W1 and 12mm+0.75W1 (W1 is the total height of the antenna cavity) is set around the antenna, and the material is set to seawater. The relevant results are as follows Fig.10 shown.

[0069] from Fig.10 It can be seen that with the increase of seawater depth, the reflection coefficient of the 1.6GHz resonance point is still less than -10dB, and the frequency bands of the three depths S11<-10dB all include 1.57-1.64GHz, including the BeiDou-1 uplink 1.610-1.626GHz, which can be used as a receiving device on the sea surface. Due to the poor ability of microwave band electromagnetic waves to penetrate seawater, this omnidirectional antenna is equivalent to a directional antenna when working on the sea surface, and the size of its buoyancy on the sea surface can be adjusted to further adjust the range of the elevation angle of the antenna to receive satellite signals.

[0070] According to a preferred embodiment of the present application, the diameter of the cylindrical side of the omnidirectional circularly polarized antenna is preferably 42.4 mm, and it can be conformal to the submarine cable, while its gain and beam width are improved by forming a linear antenna array.

[0071] In summary, according to the dual-frequency circularly polarized antenna of the present invention, by re-studying and improving its overall structural composition and key design parameters, a compact, low-cost and high-gain dual-frequency circularly polarized antenna can be obtained, which does not require a complex feeding network and matching network. The designed antenna realizes dual-frequency circular polarization based on slot coupling. Compared with the influence of direct feeding and coupled feeding radiation performance, coupled feeding can improve the overall performance of the omnidirectional radiating antenna. In addition, the present application realizes the omnidirectional radiation of the antenna by using a cylindrical cavity as the radiating body of the antenna and opening mutually perpendicular "X"-shaped slots on the cavity wall, and by adjusting the spacing between the array slots and the size of the coaxial line at the impedance matching end, it can finally achieve a better rotation direction and axial ratio within the predetermined frequency range, and can still maintain a good reflection coefficient when a waterproof cover is added, so it is particularly suitable for applications such as receiving sea surface positioning information, and has broad engineering application prospects.

[0072] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A miniaturized sea surface positioning information receiving device, characterized in that: The device has a main structure composed of a cylindrical cavity and a truncated cone, and constitutes a circularly polarized omnidirectional antenna including a radiation unit, an impedance matching element and a feeding element, wherein: The radiation unit has three groups of parallel X-shaped slots, which are sequentially opened on the cavity wall of the cylindrical cavity along the axial direction, and the interior of the cylindrical cavity is correspondingly provided with a filling section made of dielectric material; wherein the center distance between the first group of X-shaped slots located at the tail end of the antenna and the second group of X-shaped slots adjacent thereto is set to be smaller than the center distance between the second group of X-shaped slots and the third group of X-shaped slots located at the head end of the antenna; The impedance matching element is formed by connecting three sections of cylinders with different diameters, which are coaxially installed inside the cylindrical cavity of the main structure, and are used to match the feeding element with the filling section composed of the dielectric material; wherein the diameters of the three sections of coaxially installed cylinders are gradually increased between the filling section and the feeding element; The feeding element is installed inside the frustum of the main structure and is in a frustum cone shape coaxial with the impedance matching element.

2. The miniaturized sea surface positioning information receiving device according to claim 1, characterized in that: For the radiation unit, two slots in each group of X-shaped slots are perpendicular to each other and have a phase difference of 90°.

3. The miniaturized sea surface positioning information receiving device according to claim 2, characterized in that: For the radiation unit, each group of X-shaped slots is preferably arranged at an angular interval of β / 4 along the cylindrical center of the main structure, wherein β represents a medium wavelength.

4. The miniaturized sea surface positioning information receiving device according to claim 3, characterized in that: For the radiation unit, the length H of each slot in each group of X-shaped slots is preferably designed to be Where β represents the medium wavelength.

5. The miniaturized sea surface positioning information receiving device according to any one of claims 1 to 4, characterized in that: For the impedance matching element, the diameter ratio of the three coaxially mounted cylinders is preferably designed to be 7:9:

11.

6. The miniaturized sea surface positioning information receiving device according to claim 5, characterized in that: For the impedance matching element, the length ratio of the three coaxially mounted cylinders is preferably designed to be 1:1:

1.

7. The miniaturized sea surface positioning information receiving device according to any one of claims 1 to 6, characterized in that: For the feeding element, the diameter ratio of the upper and lower bottom surfaces thereof is preferably designed to be equal to the ratio of the minimum diameter to the maximum diameter of the main body structure.

8. The miniaturized sea surface positioning information receiving device according to any one of claims 1 to 7, characterized in that: The above-mentioned miniaturized sea surface positioning information receiving device is preferably used as an L-band satellite antenna of the Beidou navigation system.

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