Circularly polarized magnetoelectric dipole antenna with dual-port coaxial feed

Abstract

The invention discloses a dual-port coaxial feed circular polarization magnetoelectric dipole antenna, and belongs to the technical field of millimeter wave satellite communication antennas. The antenna comprises a first metal patch layer, a dielectric substrate a, a second metal patch layer, a dielectric substrate b and a metal ground which are sequentially stacked from top to bottom, the second metal patch layer comprises four radiation patches which are arranged in a rectangular array, and each radiation patch is composed of a square patch and a circular ring patch at an inner corner; a metal through hole is formed in the dielectric substrate and is connected with the radiation patch and the metal ground, so that a magnetoelectric dipole radiation path is formed; the first metal patch layer is provided with a probe patch a, the center of the second metal patch layer is provided with a probe patch b, and the probe patch a and the probe patch b form two space orthogonal inverted L-shaped feed probes through a short column and a long column respectively; and the inner conductors of the two feed ports are respectively connected with the long columns of the two probes. The antenna has the advantages of wide impedance bandwidth, wide beam coverage, low profile and easy integration, and is suitable for a low-orbit satellite communication terminal.

Description

Technical Field

[0001] This invention belongs to the field of millimeter-wave satellite communication antenna technology, specifically relating to a dual-port coaxially fed circularly polarized magnetoelectric dipole antenna. Background Technology

[0002] With the rapid development of wireless communication technology, low-orbit satellite communication has become a key technology for filling the coverage gaps of terrestrial communication and meeting the needs of high-speed and high-capacity communication due to its low latency, high flexibility, strong anti-interference ability and scalability. Its application value in remote area communication, emergency rescue, aerospace and other fields is becoming increasingly prominent.

[0003] As the core hub for signal transmission between the ground and satellite in low-Earth orbit (LEO) satellite communication systems, the performance of the antenna directly determines the stability, coverage, and signal quality of the communication link. This is especially true in the millimeter-wave band, where the short wavelength and high propagation loss of electromagnetic waves impose even more stringent requirements on the antenna's circular polarization capability, beam coverage, and integration. Using traditional linearly polarized antennas leads to severe polarization loss during signal transmission, significantly reducing communication quality. Furthermore, signal interference and attenuation caused by multipath propagation further affect the reliability of the communication system. Therefore, circularly polarized antennas with anti-polarization mismatch and multipath interference suppression capabilities are the preferred solution for LEO satellite communication terminals.

[0004] Magnetoelectric dipole antennas have attracted widespread attention in the field of millimeter-wave communication due to their advantages such as wide bandwidth, low cross-polarization, and high front-to-back ratio. For example, existing research has proposed a magnetoelectric dipole antenna suitable for 60GHz millimeter-wave applications, which achieves an impedance bandwidth of 51% and a stable gain of about 8dBi through a multi-metal patch and metal through-hole structure. However, this type of antenna can only achieve linear polarization radiation, which cannot meet the requirements of satellite communication for circular polarization characteristics. In addition, its half-power beamwidth is relatively narrow, making it difficult to cover the wide beam range required for low-Earth orbit satellite communication, thus limiting its application in satellite communication scenarios.

[0005] To address the limitations of linearly polarized antennas, some studies have attempted to improve magnetoelectric dipole antennas to achieve circularly polarized radiation. However, existing improvement schemes still have significant shortcomings: on the one hand, while some designs can achieve circular polarization, they are not optimized for beamwidth, resulting in insufficient gain at low elevation angles and failing to meet the requirements for wide beam coverage; on the other hand, a few wide-beam circularly polarized antenna designs suffer from problems such as complex structures, excessively high profiles, or high manufacturing costs, making it difficult to adapt to the requirements of millimeter-wave communication terminals for miniaturization, low cost, and high integration.

[0006] In summary, the current low-Earth orbit satellite communication field urgently needs a millimeter-wave antenna that combines wide beam coverage, stable circular polarization radiation, low profile, and easy integration to solve the technical bottlenecks of traditional antennas in polarization adaptation, beam range, and structural integration, and meet the urgent need of low-Earth orbit satellite communication systems for high-performance terminal antennas.

[0007] Against this backdrop, this invention proposes a dual-port coaxially fed circularly polarized magnetoelectric dipole antenna design. This design utilizes a cross-arranged Γ-shaped feed probe assembly structure, combined with a magnetoelectric dipole radiating element composed of a metal via-radiating patch, to achieve stable circularly polarized radiation by forming a 90° phase difference through dual-port orthogonal feeding. This aims to address the technical challenges of traditional magnetoelectric dipole antennas, such as lack of circular polarization, narrow beamwidth, and complex structure. Summary of the Invention

[0008] To overcome the shortcomings of the aforementioned background technology, this invention provides a dual-port coaxially fed circularly polarized magnetoelectric dipole antenna. This antenna optimizes impedance matching characteristics and radiation efficiency, and combined with a compact, low-profile design, it offers advantages such as wide beam coverage, high front-to-back ratio, and easy integration, effectively meeting the needs of millimeter-wave low-Earth orbit satellite communication scenarios.

[0009] The objective of this invention is achieved as follows: A dual-port coaxially fed circularly polarized magnetoelectric dipole antenna includes, from top to bottom, a first metal patch layer, a dielectric substrate a, a second metal patch layer, a dielectric substrate b, and a metal ground. The main body of the first metal patch layer is a probe patch a located at the center of the dielectric substrate a; short pillars a are pre-embedded in the dielectric substrate a; The second metal patch layer includes four radiating patches, which form a rectangular array of two rows and two columns; each radiating patch is a square patch, and the inner corners of the square patch are connected to circular patch; a probe patch b is provided at the center of the four radiating patches; The dielectric substrate has pre-embedded short pillars b and four metal through holes; the metal through holes correspond one-to-one with the radiating patches, the bottom end of the metal through holes is connected to the upper surface of the metal ground, and the top end passes through the annular patch and is located on the upper surface of the dielectric substrate a, so as to construct the radiating path. The probe patch a has a short post a connected to one end of its lower surface and a long post a connected to the other end of its lower surface. The bottom end of the long post a is exposed to the metal ground and does not contact the metal ground. The probe patch b has a short post b connected to one end of its lower surface and a long post b connected to the other end of its lower surface. The bottom end of the long post b is exposed to the metal ground and does not contact the metal ground.

[0010] Furthermore, the probe patch a is located directly above the probe patch b, and the two are perpendicular to each other; wherein the probe patch a, the short post a, and the long post a constitute a U-shaped feed probe a; the probe patch b, the short post b, and the long post b constitute a U-shaped feed probe b.

[0011] Furthermore, it also includes two power supply ports, the outer conductors of which are connected to the metal ground, and the inner conductors of which are connected to long post a and long post b, respectively.

[0012] Furthermore, the center of the circular patch coincides with the inner vertex of the square patch.

[0013] Furthermore, the four radiating patches are centrally symmetrically distributed on the upper surface of the dielectric substrate b.

[0014] Furthermore, the probe patches of the two Г-shaped feed probes are arranged crosswise in the central area enclosed by the four radiating patches; both dielectric substrate a and dielectric substrate b are made of Taconic TSM-DS3 high-frequency dielectric board with a dielectric constant of 3 and a loss tangent of 0.0011.

[0015] Compared with the prior art, the present invention has the following advantages: 1. To address the problem that traditional magnetoelectric dipole antennas are mostly linearly polarized and easily affected during transmission, this invention uses two cross-arranged Г-shaped feed probes to form orthogonal current distributions and a 90° phase difference through dual-port coaxial feeding, stably synthesizing circularly polarized waves, effectively resisting polarization mismatch and multipath interference, and adapting to the needs of low-orbit satellite communication scenarios.

[0016] 2. By optimizing impedance matching through a combination structure of a double-layer Taconic TSM-DS3 high-frequency dielectric substrate and a metal via-radiating patch, S-band impedance matching is achieved in the 26.0GHz-37.2GHz frequency band. 11 <-10dB, with a relative impedance bandwidth of up to 35%, covering the Ka millimeter-wave band commonly used in low-Earth orbit satellite communication; at the same time, the gain is stable at around 6.5dB within the operating frequency band, which better meets the gain flatness requirements of high-speed signal transmission compared to similar narrowband antennas.

[0017] 3. The overall height of the antenna is only 1.651mm (approximately 0.165λ, where λ is the wavelength corresponding to the center frequency). It adopts a Г-type feed probe to reduce the size of the feed structure, eliminating the need for complex assembly processes and making it easier to integrate into miniaturized devices such as low-orbit satellite communication terminals.

[0018] 4. By optimizing the size of the radiating patch and the layout of the Г-shaped probe, the half-power beamwidth of both the XOZ and YOZ planes of the antenna reaches over 90°, the front-to-back ratio exceeds 20dB, and the signal reception capability at low elevation angles is strong. Attached Figure Description

[0019] Figure 1 This is an exploded view of the overall structure of an embodiment of the present invention.

[0020] Figure 2 This is a diagram showing the positional relationship of the Г-type power supply probe in an embodiment of the present invention.

[0021] Figure 3 This is an overall perspective view of an embodiment of the present invention.

[0022] Figure 4 This is a side view of a dual-port coaxially fed circularly polarized magnetoelectric dipole antenna.

[0023] Figure 5 It is the impedance matching of the antenna S 11 Line graph.

[0024] Figure 6 This is the gain diagram of the antenna.

[0025] Figure 7 This is the axial ratio diagram of the antenna.

[0026] Figure 8 These are the radiation patterns of the antenna's E-plane and H-plane.

[0027] In the figure: 1. Dielectric substrate a, 2. Dielectric substrate b, 3. Radiation patch, 4. Metal via, 5. G-type feed probe a, 6. Metal ground, 7. Feed port, 8. First metal patch layer, 5-1. Probe patch a, 5-2. Long post a, 5-3. Short post a, 10-1. Probe patch b, 10-2. Long post b, 10-3. Short post b, 3-1. Square patch, 3-2. Circular patch, 9. Second metal patch layer. Detailed Implementation

[0028] The present invention will now be described in further detail.

[0029] A dual-port coaxially fed circularly polarized magnetoelectric dipole antenna, the specific structure of which is as follows: Figures 1 to 4 As shown, the antenna employs a multi-layer stacked design, consisting of a first metal patch layer 8, a dielectric substrate a1, a second metal patch layer 9, a dielectric substrate b2, and a metal ground layer 6, from top to bottom. All layers are tightly bonded together using printing or lamination processes to form a low-profile, highly integrated antenna module.

[0030] The main body of the first metal patch layer 8 is a probe patch a5-1 located at the center of the upper surface of the dielectric substrate a1. This patch is rectangular and serves as the horizontal radiating segment of the upper Γ-shaped feed probe a5. The dielectric substrate a1 uses Taconic TSM-DS3 high-frequency dielectric material, which has a dielectric constant of 3, a loss tangent of 0.0011, and a thickness of 0.127 mm, exhibiting good millimeter-wave transmission performance and mechanical stability. A short post a5-3 is pre-embedded inside the dielectric substrate a1, and the upper end of the short post is connected to the lower surface of the probe patch a5-1.

[0031] The second metal patch layer 9 is located between dielectric substrate a1 and dielectric substrate b2, and contains four identical radiating patches 3. These four radiating patches 3 are centrally symmetrically distributed with the antenna center as the symmetry point, arranged in a rectangular array of two rows and two columns. Each radiating patch 3 consists of two parts: a main body is a square patch 3-1, and a circular patch 3-2 is connected to one of its inner corners, the center of which coincides with the vertex of the inner corner of the square patch 3-1. This combination of square and circular design is beneficial for optimizing current distribution and expanding the impedance bandwidth and radiation beamwidth of the antenna. In the central region enclosed by the four radiating patches 3, a probe patch b10-1 is provided, which is located on the second metal patch layer 9 and serves as the horizontal part of the lower Γ-shaped feed probe b.

[0032] The dielectric substrate b2 is located below the second metal patch layer 9. It is also made of Taconic TSM-DS3 material with a thickness of 1.524 mm and has the same planar dimensions as the dielectric substrate a1. Short pillars b10-3 are pre-embedded within the dielectric substrate b2, and four metal through-holes 4 are vertically positioned at the center of the annular patch 3-2 corresponding to the four radiating patches 3. The bottom end of each metal through-hole 4 connects to the upper surface of the lowest metal ground layer 6, and the top end vertically penetrates the dielectric substrate b2, the annular patch 3-2, and the dielectric substrate a1, terminating near the upper surface of the dielectric substrate a1. This connects the radiating patches 3 to the metal ground layer 6, constructing a complete magnetoelectric dipole radiation path. The metal ground layer 6 is a rectangular metal layer covering the entire lower surface of the dielectric substrate b2, serving as the antenna's ground plane and reflector.

[0033] The antenna's feeding system consists of two identical, spatially orthogonal Γ-type feed probes. The upper one, called Γ-type feed probe a5, comprises a probe patch a5-1 located at the top layer, a short post a5-3 extending downwards from one end of the patch, and a long post a5-2 extending downwards from the other end of the patch. The bottom end of the long post a5-2 passes through an opening in the metal ground 6 and protrudes below the metal ground 6, remaining insulated from and not in contact with it. Similarly, the lower Γ-type feed probe b comprises a probe patch b10-1, a short post b10-3, and a long post b10-2. Crucially, probe patch a5-1 and probe patch b10-1 are spatially orthogonal. The vertical portions of the two probes are shown.

[0034] Two coaxial feed ports 7 are welded and fixed to the lower surface of the metal ground 6. The outer conductor of each port is connected to the metal ground 6, while the inner conductor is connected to the bottom ends of the exposed long post a 5-2 and long post b 10-2, respectively. Thus, the signal is input independently through the two ports and excites two orthogonal Γ-shaped feed probes respectively.

[0035] Figure 2 The orthogonal positional relationship of the horizontal sections of the two Г-shaped feed probes is clearly shown. Figure 3 The perspective view presents a three-dimensional view of the spatial layout between the four radiating patches 3, the probe patch in the central area, and the metal through-hole 4 penetrating the structure.

[0036] Reference Figure 3 and Figure 4 Its structural dimensions are (in millimeters): Structure a has a length of 5, structure b has a length of 0.9, structure c has a length of 0.36, structure d has a length of 1.44, structure e has a length of 0.55, structure f has a length of 1.05, structure g has a length of 0.36, structure h has a length of 0.27, structure i has a length of 0.675, structure j has a length of 1.524, structure k has a length of 1.651, and structure m has a length of 0.38.

[0037] The working principle of this invention is as follows: When two excitation signals with equal amplitude and a 90-degree phase difference are input to the antenna through two feed ports 7, the signals are transmitted to two orthogonal Γ-shaped feed probes through long pillars a5-2 and b10-2, respectively. The current on the probes is coupled to four radiating patches 3, exciting the current on the radiating patches 3. Since the two probes are spatially orthogonal and the excitation signals have a 90-degree phase difference, the electric field vectors they radiate in space are equal in magnitude, orthogonal in direction, and have a 90-degree phase difference, thus synthesizing a circularly polarized wave. The four symmetrically distributed radiating patches 3, together with the metal through-hole 4 connected to the metal ground 6, form a broadband magnetoelectric dipole radiator, which not only expands the impedance bandwidth but also effectively broadens the antenna's radiation beam.

[0038] from Figure 5 Display antenna impedance matching S 11 The graph shows that the antenna's center frequency is 30 GHz, and its reflection coefficient S is within the 26.0 GHz-37.2 GHz frequency band. 11 <-10dB, with a relative impedance bandwidth of up to 35%.

[0039] Figure 6 The gain curve shows that the antenna gain is stable at around 6.5 dB throughout the entire operating frequency band, with very little fluctuation, which meets the requirements of high-speed communication for gain flatness.

[0040] Figure 7 This indicates that the antenna's axial ratio is consistently less than 2dB within the operating frequency band, demonstrating its excellent circular polarization radiation performance.

[0041] Figure 8 The radiation patterns of the E-plane and H-plane shown indicate that the half-power beamwidth of both main planes exceeds 90 degrees, and the front-to-back ratio is higher than 20 dB, indicating that the antenna has wide beam coverage and good low-elevation angle reception performance, and can effectively resist multipath interference.

[0042] In summary, this dual-port coaxially fed circularly polarized magnetoelectric dipole antenna, through its innovative multi-layer orthogonal feeding structure and magnetoelectric dipole radiator design, successfully achieves characteristics such as wide bandwidth, wide beam, stable circularly polarized radiation, and low profile height in the millimeter-wave band. Its compact structure and ease of integration via printed circuit board processing make it highly suitable for use in low-Earth orbit satellite communication terminal equipment where antenna performance and miniaturization requirements are extremely high.

Claims

1. A dual-port coaxially fed circularly polarized magnetoelectric dipole antenna, characterized in that, It includes a first metal patch layer (8), a dielectric substrate a (1), a second metal patch layer (9), a dielectric substrate b (2), and a metal ground layer (6) stacked sequentially from top to bottom. The main body of the first metal patch layer (8) is a probe patch a (5-1) located at the center of the dielectric substrate a (1); short pillars a (5-3) are pre-embedded in the dielectric substrate a (1). The second metal patch layer (9) includes four radiating patches (3), which form a 2×2 rectangular array; each radiating patch (3) is a square patch (3-1) with a circular patch (3-2) connected to the inner corner of the square patch (3-1); a probe patch b (10-1) is provided at the center of the four radiating patches (3). The dielectric substrate has a pre-embedded short post b (10-3) and four metal through holes (4); the metal through holes (4) correspond one-to-one with the radiation patch (3), the bottom end of the metal through hole (4) is connected to the upper surface of the metal ground (6), and the top end passes through the circular patch (3-2) and is located on the upper surface of the dielectric substrate a (1). One end of the probe patch a (5-1) is connected to a short post a (5-3) on its lower surface, and the other end is connected to a long post a (5-2) on its lower surface. The bottom end of the long post a (5-2) is exposed on the metal ground (6) and does not contact the metal ground (6). One end of the probe patch b (10-1) is connected to a short post b (10-3) on its lower surface, and the other end is connected to a long post b (10-2) on its lower surface. The bottom end of the long post b (10-2) is exposed on the metal ground (6) and does not contact the metal ground (6).

2. The dual-port coaxially fed circularly polarized magnetoelectric dipole antenna according to claim 1, characterized in that, The probe patch a (5-1) is located directly above the probe patch b (10-1), and the two are perpendicular to each other; wherein the probe patch a (5-1), the short post a (5-3) and the long post a (5-2) constitute the Γ-type feed probe a (5); the probe patch b (10-1), the short post b (10-3) and the long post b (10-2) constitute the Γ-type feed probe b.

3. The dual-port coaxially fed circularly polarized magnetoelectric dipole antenna according to claim 1, characterized in that, It also includes two power supply ports (7), the outer conductors of the two power supply ports (7) are connected to the metal ground (6), and the inner conductors of the two power supply ports (7) are connected to the long column a (5-2) and the long column b (10-2) respectively.

4. A dual-port coaxially fed circularly polarized magnetoelectric dipole antenna according to claim 1, characterized in that, The center of the circular patch (3-2) coincides with the inner vertex of the square patch (3-1).

5. A dual-port coaxially fed circularly polarized magnetoelectric dipole antenna according to claim 2, characterized in that, Four radiating patches (3) are centrally symmetrically distributed on the upper surface of dielectric substrate b (2).

6. A dual-port coaxially fed circularly polarized magnetoelectric dipole antenna according to claim 2, characterized in that, The probe patches of the two Г-type feed probes are arranged crosswise in the central area enclosed by the four radiation patches (3); both dielectric substrate a (1) and dielectric substrate b (2) are made of Taconic TSM-DS3 high-frequency dielectric board with a dielectric constant of 3 and a loss tangent of 0.0011.

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