A high-gain dual-polarized magnetoelectric dipole antenna

Abstract

The application relates to the technical field of communication antennas, in particular to a high-gain dual-polarized magnetoelectric dipole antenna. The antenna comprises a first dielectric substrate, a second dielectric substrate and a metal floor, and a metal column and a coaxial feed line, wherein the first dielectric substrate, the second dielectric substrate and the metal floor are sequentially and parallelly distributed from a top layer to a bottom layer; a square metal patch, a loading patch and a first microstrip line are printed in the first dielectric substrate; a second microstrip line is printed on the top surface of the second dielectric substrate; and an L-shaped metal patch is printed on the bottom surface of the second dielectric substrate. The antenna adopts a patch loading mode, the length of a transmission line is controlled to make the current phase of the loading patch consistent with that of an electric dipole, thereby increasing the gain of the antenna, an extra feed network is not needed, the gain of a unit antenna can reach 13.7 dB, and the gain is stable within a bandwidth. Meanwhile, a folded magnetic dipole is adopted, so that the thickness of the antenna is reduced to about 0.13 wavelengths. Finally, a feed of an orthogonal structure is adopted to realize dual polarization.

Description

Technical Field

[0001] This invention relates to the field of communication antenna technology, and in particular to a high-gain dual-polarized magnetoelectric dipole antenna. Background Technology

[0002] There are currently two main methods to improve antenna gain:

[0003] First, utilize antenna arrays to improve antenna gain: Array antennas are composed of basic antennas with the same structure and size arranged according to a certain pattern, based on the principle of electromagnetic wave interference in space. Array antennas can easily achieve extremely narrow beams, and for a given beamwidth of individual antenna elements, there is a specific array spacing that maximizes the array gain. Antenna array theory shows that appropriately adjusting the structure, number, arrangement of array elements, as well as the current amplitude and phase distribution of the entire array, can effectively improve antenna gain.

[0004] Secondly, lens antennas can be used to improve antenna gain: Lens antennas are designed to collimate incident energy in nature that diverges in the desired direction. A point source acts as a feed to the surface of an optical lens, which forces the radiating spherical wavefront to become a collimated wavefront. This prevents unwanted energy diffusion, thus increasing the antenna gain. In general practice, collimating lenses are made of dielectric materials with a finite dielectric constant. However, these can also be constructed using materials that exhibit a refractive index less than unit at radio frequencies. Lens antennas follow the reciprocity theorem and can therefore be used at both the transmitting and receiving ends.

[0005] The existing methods for realizing magnetoelectric dipoles include the following:

[0006] Magnetoelectric dipole antennas are based on the complementary source principle. They combine electric dipole elements and magnetic dipole elements and simultaneously feed them to obtain similar electric and magnetic fields, giving them a wide impedance bandwidth and good radiation performance.

[0007] First, in the early stages of the development of magnetoelectric dipole antennas, conical dipoles were used as electric dipoles, which were then combined with slot-equivalent magnetic dipoles to form magnetoelectric dipoles. However, this inverted conical structure required connection to a coaxial line and had an extremely unstable structure.

[0008] Secondly, subsequent implementations used an inverted L-shaped bent wire as an electric dipole and a rectangular gap in the ground plane as a magnetic dipole, but the impedance bandwidth was still relatively narrow and the gain was unstable.

[0009] Third, Professor Lu then proposed a copper radiating patch bent at 90°. The vertical part is a vertically oriented short-circuit patch shorted to the ground plane to form a magnetic dipole. The horizontal part is a quarter-wavelength radiating plate as an electric dipole, and the middle is fed by a Γ-shaped feed line. This structure has a relative bandwidth of 43.8% and a stable gain.

[0010] The above methods have the following shortcomings:

[0011] The disadvantages of using antenna arrays to improve antenna gain are: the need for complex feeding networks, which increases design difficulty; high losses, which result in low antenna efficiency; and especially for dual-polarized antennas, which require the design of two feeding networks, further increasing design complexity.

[0012] The disadvantages of using lens antennas to improve antenna gain are that they are generally large in size, have low production efficiency, are not easy to manufacture, and often have high manufacturing costs.

[0013] The disadvantages of using a conical oscillator and a gap as a magnetoelectric dipole are: excessive size and difficulty in assembly and stability.

[0014] The disadvantages of using an inverted L-shaped bend and a radiating gap as a magnetoelectric dipole are: narrow impedance bandwidth and unstable gain.

[0015] The disadvantage of using a 90° bent copper sheet, ground plane, and Γ-shaped feed line as a magnetoelectric dipole is that the length of the magnetic dipole patch is one-quarter of a wavelength, which increases the antenna's cross-section. Summary of the Invention

[0016] This invention provides a high-gain dual-polarized magnetoelectric dipole antenna, aiming to solve the shortcomings of antenna gain methods and existing magnetoelectric dipole antennas.

[0017] This invention provides a high-gain dual-polarized magnetoelectric dipole antenna, comprising a first dielectric substrate, a second dielectric substrate, a metal ground plane, a metal pillar, and a coaxial feed line, wherein the first dielectric substrate, the second dielectric substrate, and the metal ground plane are arranged in parallel from the top layer to the bottom layer.

[0018] The first dielectric substrate is printed with square metal patches, loading patches, and first microstrip lines. Four square metal patches are arranged in an array on the first dielectric substrate. The first microstrip lines are orthogonal to each other and located in the gaps between the square metal patches. The ends of the first microstrip lines extend outward and connect to the loading patches. The square metal patches are connected above the metal pillars.

[0019] The top surface of the second dielectric substrate is printed with a second microstrip line, and the bottom surface of the second dielectric substrate is printed with an L-shaped metal patch. The bottom of the metal pillar and the top of the outer conductor of the coaxial feed line are soldered to the L-shaped metal patch and grounded. The two second microstrip lines are orthogonal to each other. One end of the two second microstrip lines is connected to the inner conductor of the coaxial feed line, and the other end of the two second microstrip lines extends to the top of the diagonally opposite coaxial feed line. The bottom of the outer conductor of the coaxial feed line is connected to a metal ground plane.

[0020] The square metal patches located at opposite corners are coupled to generate electric dipole radiation, and the gaps between the square metal patches generate magnetic dipole radiation.

[0021] As a further improvement of the present invention, the second dielectric substrate is printed with four L-shaped metal patches, which are arranged in an array. Each L-shaped metal patch corresponds to a metal post and a coaxial feed line. Two of the coaxial feed lines diagonally serve as coaxial feed ports for achieving dual polarization, while the other two diagonally positioned coaxial feed lines are used for grounding.

[0022] As a further improvement of the present invention, in the second dielectric substrate, one set of diagonally opposite coaxial feed lines is used as a first feed port, and the other set of diagonally opposite coaxial feed lines is used as a second feed port:

[0023] When the first power supply port is excited, the square metal patches located on the diagonal are excited, and the current direction is from one square metal patch to another square metal patch. The current direction is at a 45° angle relative to the first dielectric substrate and the second dielectric substrate. The gap between the four square metal patches is coupled to form a magnetic current perpendicular to the current direction.

[0024] When the second feed port is excited, another pair of square metal patches on the opposite diagonal direction radiate as electric dipoles, and the direction of the current formed is perpendicular to the direction of the current when the first feed port is excited, forming electromagnetic radiation with a polarization direction of -45°.

[0025] As a further improvement of the present invention, the metal column is a column folded into an L-shape. The upper part of the L-shaped metal column is connected to the top corner of the square metal patch near the center of the array. The lower part of the L-shaped metal column is connected to the L-shaped opening of the L-shaped metal patch. The L-shaped opening is located on the outer side of the L-shaped metal patch away from the center of the array. The top of the outer conductor of the coaxial feed line is connected to the top corner of the L-shaped metal patch near the center of the array.

[0026] As a further improvement of the present invention, the phase of the loading patch is controlled by adjusting the length of the first microstrip line, the length of each first microstrip line being one dielectric wavelength.

[0027] As a further improvement of the present invention, the impedance of the antenna is controlled by adjusting the length of the second microstrip line.

[0028] As a further improvement of the present invention, the first dielectric substrate and the second dielectric substrate are Rogers 5880 substrates.

[0029] As a further improvement of the present invention, the loading patch is a rectangular patch.

[0030] The beneficial effects of this invention are as follows: This antenna uses a patch loading method, and by controlling the length of the transmission line, the current phase between the loaded patch and the electric dipole is made consistent, thereby increasing the antenna gain. No additional feeding network is required, and the gain of a single antenna element can reach 13.7 dB, with stable gain throughout the bandwidth. Simultaneously, a folded magnetic dipole is used, reducing its thickness from one-quarter of a wavelength to approximately 0.13 wavelengths. Finally, dual polarization is achieved using an orthogonal feeding structure. Attached Figure Description

[0031] Figure 1 This is a three-dimensional view of the high-gain dual-polarized magnetoelectric dipole antenna of the present invention;

[0032] Figure 2 This is a top view of the high-gain dual-polarized magnetoelectric dipole antenna of the present invention;

[0033] Figure 3 This is a front view of the high-gain dual-polarized magnetoelectric dipole antenna of the present invention;

[0034] Figure 4 This is a diagram of the feeding structure of the high-gain dual-polarized magnetoelectric dipole antenna of the present invention;

[0035] Figure 5 This is a schematic diagram of the magnetoelectric dipole in the high-gain dual-polarization magnetoelectric dipole antenna of the present invention;

[0036] Figure 6 This is a current distribution diagram of the patch on the first dielectric substrate of the present invention;

[0037] Figure 7 This is the S-parameter diagram of the high-gain dual-polarized magnetoelectric dipole antenna of the present invention;

[0038] Figure 8 This is a gain curve diagram of the high-gain dual-polarized magnetoelectric dipole antenna of the present invention;

[0039] Figure 9 This is the radiation pattern of the high-gain dual-polarized magnetoelectric dipole antenna of the present invention at a center frequency of 2.1 GHz. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0041] like Figures 1 to 5 As shown, a high-gain dual-polarized magnetoelectric dipole antenna of the present invention includes a first dielectric substrate 1, a second dielectric substrate 2, a metal ground plane 3, a metal pillar 4, and a coaxial feed line 5. The first dielectric substrate 1, the second dielectric substrate 2, and the metal ground plane 3 are arranged in parallel from the top layer to the bottom layer.

[0042] Square metal patches 11, loading patches 12, and first microstrip lines 13 are printed inside the first dielectric substrate 1. Four square metal patches 11 are arranged in an array on the first dielectric substrate 1. The first microstrip lines 13 are orthogonal to each other and located in the gaps between the square metal patches 11. The ends of the first microstrip lines 13 extend outward and connect to the loading patches 12. The square metal patches 11 are connected above the metal pillars 4.

[0043] The top surface of the second dielectric substrate 2 is printed with a second microstrip line 22, and the bottom surface of the second dielectric substrate 2 is printed with an L-shaped metal patch 21. The bottom of the metal pillar 4 and the top of the outer conductor 52 of the coaxial feed line 5 are soldered to the L-shaped metal patch 21 and grounded. The two second microstrip lines 22 are orthogonal to each other. One end of the two second microstrip lines 22 is connected to the inner conductor 51 of the coaxial feed line 5, and the other end of the two second microstrip lines 22 extends to the top of the diagonally opposite coaxial feed line 5. The bottom of the outer conductor 52 of the coaxial feed line 5 is connected to the metal ground plane 3.

[0044] The square metal patches 11 located at opposite corners are coupled to generate electric dipole radiation, and the gaps between the square metal patches 11 are used as magnetic dipole radiation.

[0045] The antenna's overall structure consists of two dielectric substrates, a metal ground plane 3, four L-shaped metal posts 4, and a coaxial feed line 5. The metal posts 4 connect to and short-circuit to ground the square metal patch 11 in the top first dielectric substrate 1, allowing the gaps in the square metal patch 11 to form a magnetic dipole. The coaxial feed line 5 is used to excite the electric and magnetic dipoles. Figure 1 and Figure 2The top layer, the first dielectric substrate 1, uses a Rogers 5880 substrate with a dielectric constant of 2.2. Four square metal patches 11, orthogonal first microstrip lines 13, and loaded rectangular patches are printed on the first dielectric substrate 1. The four square metal patches 11 serve as two pairs of electric dipoles for two polarization conditions. The orthogonal first microstrip lines 13 are used to adjust the phase difference of the surface currents of the square metal patches 11 and the loaded rectangular patches. The loaded rectangular patches are used to increase the antenna gain. The second dielectric substrate 2 also uses a Rogers 5880 substrate. Its top surface is printed with orthogonally placed second microstrip lines 22, and its bottom surface has L-shaped metal patch patterns 21 printed at corresponding positions, such as... Figure 4 The L-shaped metal patch 21 pattern will be soldered to the metal post 4 and the coaxial outer conductor 52 and grounded. The bottom layer is a larger metal floor 3, used to reflect electromagnetic waves to obtain better directionality.

[0046] The second dielectric substrate 2 has four L-shaped metal patches 21 printed on it. The four L-shaped metal patches 21 are arranged in an array. Each L-shaped metal patch 21 corresponds to a metal post 4 and a coaxial feed line 5. Two diagonally opposite coaxial feed lines 5 serve as coaxial feed ports for dual polarization, and the other two diagonally opposite coaxial feed lines 5 are used for grounding. Each metal post 4 has a corresponding coaxial feed line 5 below it. Only two of these serve as the first coaxial feed port 53 and the second coaxial feed port 54 for dual polarization, and the remaining two are used for grounding.

[0047] Implementation of a dual-polarized magnetoelectric dipole antenna:

[0048] In the second dielectric substrate 2, one set of diagonally opposite coaxial feed lines 5 serves as the first feed port 53, and the other set of diagonally opposite coaxial feed lines 5 serves as the second feed port 54.

[0049] like Figure 4 As shown, the specific structure of the two feed ports is as follows: orthogonal second microstrip lines 22 are printed on the second dielectric substrate 2 for feeding the two ports. One end of each of the two second microstrip lines 22 is connected to the inner conductor 51 of the coaxial feed line 5, and the outer conductor 52 of the coaxial feed line 5 is connected to and grounded to the L-shaped metal patch 21 below the second dielectric substrate 2. The other end of the second microstrip line 22 extends to the top of the diagonally opposite coaxial feed line 5, equivalent to a capacitor, which excites the square metal patch 11 located at the diagonal position as an electric dipole radiation through coupling. The gap between the square metal patches 11 serves as a magnetic dipole radiation, forming a magnetoelectric dipole antenna. The length of the second microstrip line 22 has a significant impact on the impedance matching of the antenna; the impedance of the antenna is controlled by adjusting the length of the second microstrip line 22.

[0050] like Figure 5As shown, when the first feed port 53 is excited, the square metal patches 11 located on the diagonal are excited, and the resulting current direction is from one patch to another. As indicated by the arrow, the current direction is at a 45° angle relative to the first dielectric substrate 1 and the second dielectric substrate 2. The gaps between the four square metal patches 11 are coupled to form a magnetic current perpendicular to the current direction. The combination of current and magnetic current forms a magnetoelectric dipole antenna, which has nearly identical electric and magnetic field surfaces and stable radiation.

[0051] When the second feed port 54 is excited, the other pair of diagonally opposite square metal patches 11 radiate as electric dipoles, and the resulting current direction is perpendicular to the current direction when the first feed port 53 is excited, forming electromagnetic radiation with a polarization direction of -45°. This dual-polarized antenna has a simple feeding configuration and similar impedance bandwidth and radiation pattern in both polarization cases.

[0052] The metal pillar 4 is a pillar folded into an L-shape. The top of the L-shaped metal pillar 4 is connected to the top corner of the square metal patch 11 near the center of the array, and the bottom of the L-shaped metal pillar 4 is connected to the L-shaped opening of the L-shaped metal patch 21. The L-shaped opening is located on the outer side of the L-shaped metal patch 21 away from the center of the array. The top of the outer conductor 52 of the coaxial feed line 5 is connected to the top corner of the L-shaped metal patch 21 near the center of the array. The L-shaped metal pillar 4 serves as the connecting conductive pillar between the first dielectric substrate 1 and the second dielectric substrate 2. The current formed by the electric dipole flows sequentially through the square metal patch 11, the L-shaped metal pillar 4, the L-shaped metal patch 21, the outer conductor 52 of the coaxial feed line 5, and the metal ground plane 3, causing the current path to bend vertically and form a stepped path shape.

[0053] like Figure 5 The dashed line in the diagram is a simplified schematic of a magnetoelectric dipole antenna. The horizontal direction represents the electric dipole, and the structure in the vertical direction is folded. Although the grounding path remains unchanged at one-quarter wavelength, the folding reduces the short-circuit post, which originally required one-quarter wavelength, to 0.13 wavelength, thus lowering the overall profile of the antenna.

[0054] Implementation of gain enhancement:

[0055] The gain is primarily increased through radiation from the four rectangular loading patches 12 on the first dielectric substrate 1, and secondly by using a larger metal ground plane 3 to reflect the back-radiated electromagnetic waves, thereby reducing the antenna's back lobe and increasing its gain. The specific implementation principle can be derived from... Figure 6 The explanation is that the HFSS electromagnetic simulation software was used to calculate the current distribution on the patch at various times. Figure 6The diagram shows the current vector on the metal patch at the same moment. It can be seen that the current direction of both the square metal patch 11 (acting as an electric dipole) and the loaded patch 12 points to the left. Therefore, the electromagnetic waves radiated by the patch are superimposed in phase in the air, increasing the antenna gain.

[0056] The phase of the loading patch 12 is primarily controlled by adjusting the length of the cross-shaped first microstrip line 13. The length of each first microstrip line 13 should be maintained at one dielectric wavelength, ensuring that the loading patches 12 at both ends of the first microstrip line 13 have the same current phase. The energy of the loading patch 12 and the first microstrip line 13 is coupled through the gap between the electric dipoles. The first microstrip line 13 does not act as a radiating element but is only used for phase control. It can be seen that in the central region, the current direction on the first microstrip line 13 is opposite to that of the electric dipole. After transmission through a microstrip line of half a dielectric wavelength, the current direction on the loading patch 12 will align with that of the electric dipole, thereby improving the antenna gain.

[0057] This antenna employs a patch loading method. By adjusting the length of the cross-shaped first microstrip line 13, the current phase of the loaded patch 12 is made to match the phase of the electric dipole, thereby increasing the antenna gain. This results in a unit gain of 13.7 dB for both polarizations, while maintaining stable gain. The entire structure requires no feed network, and the feeding process is simple.

[0058] Simulation results explanation:

[0059] The antenna model was designed and simulated using HFSS electromagnetic simulation software, and the results are as follows: Figure 7 The indicator chart. Figure 7 This is the S-parameter diagram of the antenna, S 11 and S 22 The curves show the impedance matching of the first feed port 53 and the feed from the first feed port 53, respectively. When it is less than -10dB, it indicates good impedance matching, and energy can enter the antenna well. 21 This represents the isolation between the two feed ports; the smaller the value, the less influence there is between the ports. As can be seen from the figure, S... 11 and S 22 It can maintain a voltage level below -10dB in the 1.7~2.6GHz frequency range, has an impedance bandwidth of 41.8%, and provides good isolation.

[0060] Figure 8 The gain curve of this antenna shows that it achieves a maximum gain of 13.7 dB at 2.45 GHz, and the gain remains very stable at high frequencies. Without an antenna array, the gain is comparable to that of most 2×2 magnetoelectric dipole antenna arrays.

[0061] Figure 9The image shows the radiation pattern of the antenna at the center frequency of 2.1 GHz. The two curves represent the electric field and magnetic field, respectively. It can be seen that the antenna has good directional radiation characteristics, low back lobe, and a wide 3 dB beamwidth.

[0062] Compared to existing dual-polarized magnetoelectric dipole antenna arrays that achieve high gain but require separate feeding networks for each polarization, increasing complexity, the high-gain dual-polarized magnetoelectric dipole antenna proposed in this invention can achieve a gain of 13.7 dB without the need for antenna arrays or lenses. Typically, other magnetoelectric dipole antenna elements have a gain of no more than 8 dB, requiring four antenna elements to achieve the gain of this design, necessitating additional feeding networks, increasing design difficulty and losses. This design is simple to feed and fabricate, facilitating mass production.

[0063] This invention reduces the thickness of the magnetic dipole by using a folded magnetic dipole, and simultaneously achieves dual polarization in a simple form by feeding it with a coaxial line through orthogonal microstrip lines.

[0064] This antenna achieves an impedance bandwidth of 47% in both polarizations, with a maximum gain of 13.7dB. The gain remains stable within the bandwidth, and it exhibits good radiation. It is suitable for Sub-6GHz band antenna applications (long-distance communication, base stations, etc.).

[0065] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A high-gain dual-polarized magnetoelectric dipole antenna, characterized in that, It includes a first dielectric substrate, a second dielectric substrate, a metal ground plane, a metal pillar, and a coaxial feed line, wherein the first dielectric substrate, the second dielectric substrate, and the metal ground plane are distributed in parallel from the top layer to the bottom layer; The first dielectric substrate is printed with square metal patches, loading patches, and first microstrip lines. Four square metal patches are arranged in an array on the first dielectric substrate. The first microstrip lines are orthogonal to each other and located in the gaps between the square metal patches. The ends of the first microstrip lines extend outward and connect to the loading patches. The square metal patches are connected above the metal pillars. The top surface of the second dielectric substrate is printed with a second microstrip line, and the bottom surface of the second dielectric substrate is printed with an L-shaped metal patch. The bottom of the metal pillar and the top of the outer conductor of the coaxial feed line are soldered to the L-shaped metal patch and grounded. The two second microstrip lines are orthogonal to each other. One end of the two second microstrip lines is connected to the inner conductor of the coaxial feed line, and the other end of the two second microstrip lines extends to the top of the diagonally opposite coaxial feed line. The bottom of the outer conductor of the coaxial feed line is connected to a metal ground plane. The square metal patches located at opposite corners are coupled to generate electric dipole radiation, and the gaps between the square metal patches generate magnetic dipole radiation.

2. The high-gain dual-polarized magnetoelectric dipole antenna according to claim 1, characterized in that, The second dielectric substrate has four L-shaped metal patches printed on it. The four L-shaped metal patches are arranged in an array. Each L-shaped metal patch corresponds to a metal post and a coaxial feed line. Two of the coaxial feed lines diagonally serve as coaxial feed ports for dual polarization, and the other two diagonally serve as grounding.

3. The high-gain dual-polarized magnetoelectric dipole antenna according to claim 2, characterized in that, In the second dielectric substrate, one set of diagonally opposite coaxial feed lines serves as the first feed port, and the other set of diagonally opposite coaxial feed lines serves as the second feed port: When the first power supply port is excited, the square metal patches located on the diagonal are excited, and the current direction is from one square metal patch to another square metal patch. The current direction is at a 45° angle relative to the first dielectric substrate and the second dielectric substrate. The gap between the four square metal patches is coupled to form a magnetic current perpendicular to the current direction. When the second feed port is excited, another pair of square metal patches on the opposite diagonal direction radiate as electric dipoles, and the direction of the current formed is perpendicular to the direction of the current when the first feed port is excited, forming electromagnetic radiation with a polarization direction of -45°.

4. The high-gain dual-polarized magnetoelectric dipole antenna according to claim 1, characterized in that, The metal pillar is a folded L-shaped pillar. The top of the L-shaped metal pillar is connected to the top corner of the square metal patch near the center of the array. The bottom of the L-shaped metal pillar is connected to the L-shaped opening of the L-shaped metal patch. The L-shaped opening is located on the outer side of the L-shaped metal patch away from the center of the array. The top of the outer conductor of the coaxial feed line is connected to the top corner of the L-shaped metal patch near the center of the array.

5. The high-gain dual-polarized magnetoelectric dipole antenna according to claim 1, characterized in that, The phase of the loading patch is controlled by adjusting the length of the first microstrip line, and the length of each first microstrip line is one dielectric wavelength.

6. The high-gain dual-polarized magnetoelectric dipole antenna according to claim 1, characterized in that, The impedance of the antenna is controlled by adjusting the length of the second microstrip line.

7. The high-gain dual-polarized magnetoelectric dipole antenna according to claim 1, characterized in that, The first dielectric substrate and the second dielectric substrate are Rogers 5880 substrates.

8. The high-gain dual-polarized magnetoelectric dipole antenna according to claim 1, characterized in that, The loading patch is a rectangular patch.

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