A Ultra-wideband Three-port MIMO Antenna

Abstract

The present invention provides an ultra-wideband three-port MIMO antenna, which includes a dielectric substrate, a first radiation arm, a second radiation arm, a first feeder, a second feeder and a third feeder; the first radiation arm, the second feeder and the third feeder are printed on the upper surface of the dielectric substrate, and the second radiation arm and the first feeder are printed on the lower surface of the dielectric substrate; a first circular slot is etched on the first radiation arm, and a second circular slot is etched on the second radiation arm; one end of the third feeder is electrically connected to the first radiation arm, and the other end of the third feeder is arranged above the second radiation arm; the first feeder and the second feeder are arranged parallel to the Y-axis. The present invention realizes smaller size and wider frequency band coverage through a simple and ingenious structure, and can generate an omnidirectional radiation pattern within the operating frequency band. The present invention improves the antenna performance while reducing the production cost, has high gain and high radiation efficiency, is an ideal choice for ultra-wideband applications, and has broad market prospects.

Description

Technical Field

[0001] The present invention relates to the field of communication antennas, and particularly to an ultra-wideband three-port MIMO antenna. Background Art

[0002] With the development of wireless communication technology, large channel capacity and high spectral efficiency have become the basic requirements for future wireless communication. Therefore, the ultra-wideband (UWB) communication technology with these characteristics has become a research hotspot in the communication field. At the same time, ultra-wideband communication antennas are also considered an important solution to overcome the data rate bottleneck in wireless communication.

[0003] However, ultra-wideband communication antennas generally face problems of system reliability and multipath fading. In contrast, the massive multiple-input multiple-output (MIMO) technology can communicate with multiple users within the same time-frequency resource using multiple antennas, and is one of the key technologies to achieve high data rates, improve spectral efficiency, and mitigate multipath fading. Therefore, combining the ultra-wideband (UWB) technology with the massive multiple-input multiple-output (MIMO) technology can not only provide good data rates, but also make the system immune to multipath problems.

[0004] Currently, there are some antennas that combine the ultra-wideband (UWB) technology with the massive multiple-input multiple-output (MIMO) technology, but they all have various defects and need to be further improved and perfected.

[0005] For example, the Chinese invention patent with the publication number CN113571881A proposes a small-size ultra-wideband MIMO antenna, which makes full use of the space on both sides of the substrate and reduces the occupied size of the antenna unit without affecting the performance of each antenna unit; however, the impedance bandwidth of this MIMO antenna is relatively narrow. Another example is the Chinese invention patent with the announcement number CN112563730B, which proposes a high-isolation ultra-wideband MIMO antenna suitable for 5G full-band communication, and its bandwidth reaches 1.9 GHz - 5 GHz, which can cover the main working frequency bands of the 5G full band; however, its antenna size is relatively large. Still another example is the Chinese invention patent with the publication number CN110323562A, which proposes an adjustable ultra-wideband MIMO antenna based on complementary split-ring resonators, and it achieves the technical effects of ultra-wideband and high isolation; however, its circularity is poor and the radiation pattern in the high-frequency part is unstable. Summary of the Invention

[0006] The purpose of the present invention is to provide an ultra-wideband three-port MIMO antenna for the defects in the prior art, which can achieve a wider frequency band coverage with a smaller size and can generate an omnidirectional radiation pattern within the working frequency band.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A ultra-wideband three-port MIMO antenna, comprising a dielectric substrate, a first radiation arm, a second radiation arm, a first feeder, a second feeder and a third feeder;

[0009] The dielectric substrate is disposed in the XOY plane. The first radiation arm, the second feeder and the third feeder are printed on the upper surface of the dielectric substrate, and the second radiation arm and the first feeder are printed on the lower surface of the dielectric substrate;

[0010] The first radiation arm and the second radiation arm are integrally rectangular. The first radiation arm covers half of the upper surface of the dielectric substrate near the negative X-axis direction, and the second radiation arm covers half of the lower surface of the dielectric substrate near the positive X-axis direction. The coverage areas of the first radiation arm and the second radiation arm on the dielectric substrate do not overlap; a first circular slot is etched on the first radiation arm, and a second circular slot is etched on the second radiation arm;

[0011] The third feeder is disposed parallel to the X-axis. One end of the third feeder is electrically connected to the first radiation arm, and the other end of the third feeder is disposed above the second radiation arm; a through circular hole is formed at the position of the dielectric substrate corresponding to the other end of the third feeder to form a first input port; the first input port is fed by a coaxial cable, and the coaxial cable is introduced from below the dielectric substrate. The outer conductor of the coaxial cable is electrically connected to the second radiation arm, and the inner conductor of the coaxial cable passes through the circular hole and is electrically connected to the other end of the third feeder;

[0012] The first feeder and the second feeder are disposed parallel to the Y-axis; one end of the first feeder is disposed at the edge of the dielectric substrate near the negative Y-axis direction to form a second input port, and the other end of the first feeder is disposed below the middle part of the first radiation arm; one end of the second feeder is disposed at the edge of the dielectric substrate near the positive Y-axis direction to form a third input port, and the other end of the second feeder is disposed below the middle part of the second radiation arm.

[0013] Further, the second input port is connected and fed to an external coaxial cable through a first SMA interface. The first SMA interface is welded to the side surface of the dielectric substrate corresponding to the position of the second input port. The inner pin of the first SMA interface is electrically connected to the first feeder, and the external metal of the first SMA interface is electrically connected to the first radiation arm;

[0014] The third input port is connected and fed to an external coaxial cable through a second SMA interface. The second SMA interface is welded to the side surface of the dielectric substrate corresponding to the position of the third input port. The inner pin of the second SMA interface is electrically connected to the second feeder, and the external metal of the second SMA interface is electrically connected to the second radiation arm.

[0015] Further, the first circular slot includes a first circular groove, a first rectangular groove, and a first circular notch groove. The first circular groove is etched near the middle of the first radiation arm, the first circular notch groove is etched at the side of the first radiation arm near the negative X-axis direction, and the first rectangular groove extends along the X-axis direction and connects the first circular groove and the first circular notch groove;

[0016] The other end of the first feeder is connected with a first circular metal patch for optimizing impedance matching; the first circular metal patch partially overlaps with the first circular groove for coupled feeding.

[0017] Further, the second circular slot includes a second circular groove, a second rectangular groove, and a second circular notch groove. The second circular groove is etched near the middle of the second radiation arm, the second circular notch groove is etched at the side of the second radiation arm near the positive X-axis direction, and the second rectangular groove extends along the X-axis direction and connects the second circular groove and the second circular notch groove;

[0018] The other end of the second feeder is connected with a second circular metal patch for optimizing impedance matching; the second circular metal patch partially overlaps with the second circular groove for coupled feeding.

[0019] Further, chamfers are loaded at the four corners of the first radiation arm and the second radiation arm for expanding the bandwidth of the antenna.

[0020] Further, the third feeder is in a triangular cone shape for optimizing impedance matching; the end of the third feeder facing the first radiation arm is larger than the end facing the second radiation arm.

[0021] Further, the first circular slot and the second circular slot are centrosymmetric about the center of the dielectric plate, and the first feeder and the second feeder are centrosymmetric about the center of the dielectric plate.

[0022] Further, the size of the first circular slot is exactly the same as that of the second circular slot, and the size of the first feeder is exactly the same as that of the second feeder.

[0023] Further, the first circular slot is arranged at a position slightly biased towards the negative Y-axis direction in the middle of the first radiation arm, and the second circular slot is arranged at a position slightly biased towards the positive Y-axis direction in the middle of the second radiation arm to obtain better impedance matching and circularity.

[0024] A super-wideband three-port MIMO antenna provided by the present invention is integrally composed of a dipole antenna and two slot antennas with opposite and shared structures. By respectively multiplexing the two radiation arms of the dipole antenna as the ground planes of the two slot antennas, the antenna profile is reduced and the size of the antenna is decreased. At the same time, the present invention also improves the impedance bandwidth by loading chamfers on the radiation arms and optimizing the shapes of the feeders and slots.

[0025] Compared with the prior art, the present invention achieves a smaller size and a wider frequency band coverage through a simple and ingenious structure, and can generate an omnidirectional radiation pattern within the operating frequency band. While reducing the production cost, the present invention improves the antenna performance, has high gain and high radiation efficiency, is an ideal choice for ultra-wideband applications, better realizes the combination of ultra-wideband technology and massive multiple-input multiple-output technology, and has broad market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is an exploded view of an ultra-wideband three-port MIMO antenna provided by an embodiment of the present invention.

[0027] Figure 2 is a schematic diagram of the upper surface structure of an ultra-wideband three-port MIMO antenna provided by an embodiment of the present invention.

[0028] Figure 3 is a schematic diagram of the lower surface structure of an ultra-wideband three-port MIMO antenna provided by an embodiment of the present invention.

[0029] Figure 4 is a comparison diagram of the upper and lower surface structures of an ultra-wideband three-port MIMO antenna provided by an embodiment of the present invention.

[0030] Figure 5 is a reflection coefficient diagram simulated by an embodiment of the present invention.

[0031] Figure 6 is a radiation pattern diagram simulated by an embodiment of the present invention at a frequency of 2 GHz. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The technical solutions of the present invention will be described in detail below in conjunction with the drawings and specific embodiments.

[0033] As Figures 1 to 4 shown, an ultra-wideband three-port MIMO antenna provided by an embodiment of the present invention includes a dielectric board 1, a first radiation arm 21, a second radiation arm 22, a first feeder 31, a second feeder 32, and a third feeder 33.

[0034] The dielectric board 1 is disposed in the XOY plane. The first radiation arm 21, the second feeder 32, and the third feeder 33 are printed on the upper surface of the dielectric board 1, and the second radiation arm 22 and the first feeder 31 are printed on the lower surface of the dielectric board 1;

[0035] The first radiation arm 21 and the second radiation arm 22 are integrally rectangular. The first radiation arm 21 covers half of the upper surface of the dielectric plate 1 near the negative X-axis direction, and the second radiation arm 22 covers half of the lower surface of the dielectric plate 1 near the positive X-axis direction. The coverage areas of the first radiation arm 21 and the second radiation arm 22 on the dielectric plate 1 do not overlap with each other. A first circular slot 41 is etched on the first radiation arm 21, and a second circular slot 42 is etched on the second radiation arm 22.

[0036] The third feeder 33 is arranged parallel to the X-axis. One end of the third feeder 33 is electrically connected to the first radiation arm 21, and the other end of the third feeder 33 is arranged above the second radiation arm 22. A through circular hole is formed at the position of the dielectric plate 1 corresponding to the other end of the third feeder 31 to form a first input port. The first input port is fed by a coaxial cable 5. The coaxial cable 5 is introduced from below the dielectric plate 1. The outer conductor of the coaxial cable 5 is electrically connected to the second radiation arm 22, and the inner conductor of the coaxial cable 5 passes through the circular hole and is electrically connected to the other end of the third feeder 31.

[0037] The first feeder 31 and the second feeder 32 are arranged parallel to the Y-axis. One end of the first feeder 31 is arranged at the edge of the dielectric plate 1 near the negative Y-axis direction to form a second input port, and the other end of the first feeder 31 is arranged below the middle part of the first radiation arm 21. One end of the second feeder 32 is arranged at the edge of the dielectric plate 1 near the positive Y-axis direction to form a third input port, and the other end of the second feeder 32 is arranged below the middle part of the second radiation arm 22.

[0038] The second input port is connected and fed by an external coaxial cable through a first SMA interface (not shown). The first SMA interface is welded to the side surface of the dielectric plate 1 corresponding to the position of the second input port. The inner pin of the first SMA interface is electrically connected to the first feeder 31, and the external metal of the first SMA interface is electrically connected to the first radiation arm 21.

[0039] The third input port is connected and fed by an external coaxial cable through a second SMA interface (not shown). The second SMA interface is welded to the side surface of the dielectric plate 1 corresponding to the position of the third input port. The inner pin of the second SMA interface is electrically connected to the second feeder 32, and the external metal of the second SMA interface is electrically connected to the second radiation arm 22.

[0040] Further, the first circular slot 41 includes a first circular groove 412, a first rectangular groove 411, and a first circular notch groove 413. The first circular groove 412 is etched near the middle part of the first radiation arm 21, the first circular notch groove 413 is etched at the side of the first radiation arm 21 near the negative X-axis direction, and the first rectangular groove 411 extends along the X-axis direction and connects the first circular groove 412 and the first circular notch groove 413.

[0041] The other end of the first feeder 31 is connected with a first circular metal patch 310 for optimizing impedance matching; the first circular metal patch 310 partially overlaps with the first circular groove 412 for coupled feeding.

[0042] Further, the second circular slit 42 includes a second circular groove 422, a second rectangular groove 421 and a second circular notch groove 423. The second circular groove 422 is etched near the middle of the second radiation arm 22, the second circular notch groove 423 is etched at the side of the second radiation arm 22 near the positive X-axis direction, and the second rectangular groove 421 extends along the X-axis direction and connects the second circular groove 422 and the second circular notch groove 423.

[0043] The other end of the second feeder 32 is connected with a second circular metal patch 320 for optimizing impedance matching; the second circular metal patch 320 partially overlaps with the second circular groove 412 for coupled feeding.

[0044] Further, the first circular slit 41 is arranged at a position slightly biased towards the negative Y-axis direction in the middle of the first radiation arm 21, and the second circular slit 42 is arranged at a position slightly biased towards the positive Y-axis direction in the middle of the second radiation arm 22 to obtain better impedance matching and circularity.

[0045] Further, chamfers are loaded at the four corners of the first radiation arm 21 and the second radiation arm 22 for expanding the bandwidth of the antenna.

[0046] Further, the third feeder 33 is triangular pyramid-shaped for optimizing impedance matching; the end of the third feeder 33 facing the first radiation arm 21 is larger than the end facing the second radiation arm 22.

[0047] Further, the first circular slit 41 and the second circular slit 42 are centrosymmetric about the center of the dielectric plate, and the first feeder 21 and the second feeder 22 are centrosymmetric about the center of the dielectric plate 1. The centrosymmetric distribution structure can optimize the circularity of the antenna.

[0048] Further, the size of the first circular slit 41 is exactly the same as the size of the second circular slit 42, and the size of the first feeder 21 is exactly the same as the size of the second feeder 22. The same size can make the radiation pattern more stable.

[0049] In the embodiment of the present invention, the first radiation arm, the second radiation arm, and the third feeder form a dipole antenna, and are fed through the first input port; the first feeder and the first circular slot form a slot antenna, and are fed through the second input port; the second feeder and the second circular slot form another slot antenna, and are fed through the third input port.

[0050] Specifically, when the embodiment of the present invention works, power is fed to the first input port through the coaxial cable 5. The outer conductor of the coaxial cable 5 is electrically connected to the second radiation arm 22, and the inner conductor of the coaxial cable 5 is connected to the first radiation arm 21 through the third feeder 33, so that the first radiation arm 21 and the second radiation arm 22 together form a dipole antenna. At the same time, power is fed to the second input port through the coaxial cable via the first SMA interface, and then coupled and fed to the first circular slot 41 through the first feeder 31, so that the first feeder 31 and the first circular slot 41 together form a slot antenna. In addition, power is fed to the third input port through the coaxial cable via the second SMA interface, and then coupled and fed to the second circular slot 42 through the second feeder 32, so that the second feeder 32 and the second circular slot 42 together form another slot antenna.

[0051] The present invention expands the antenna bandwidth by etching circular slots on two radiation arms and setting circular metal patches at the ends of the first feeder and the second feeder. Moreover, four chamfers are loaded at the four corners of the dipole antenna, further optimizing the 3dB bandwidth of the entire frequency band.

[0052] In the case of no decoupling network, the reflection coefficient of the ultra-wideband three-port MIMO antenna of the embodiment of the present invention is less than -12dB over the entire operating bandwidth, the port isolation is better than 12dB, the average peak gain of the three ports is 5.6dBi, and the radiation efficiency reaches 90%.

[0053] Figure 5 This is the reflection coefficient graph obtained by simulating the antenna of the embodiment of the present invention. It can be seen from the graph that in this embodiment, the frequency band where the antenna reflection coefficient is less than -12dB can cover 1.7 - 6GHz, which can fully cover the main operating frequency band of the 5G full frequency band.

[0054] Figure 6 This is the radiation pattern obtained by simulating the antenna of the embodiment of the present invention at a frequency of 2GHz. It can be seen from the graph that the antenna of this embodiment can maintain a relatively good omnidirectional radiation pattern within the frequency band it covers.

[0055] An ultra-wideband three-port MIMO antenna provided by the present invention is integrally composed of a dipole antenna and two slot antennas with opposite and shared structures. By respectively multiplexing the two radiation arms of the dipole antenna as the ground planes of the two slot antennas, the antenna profile is reduced and the size of the antenna is decreased. At the same time, the present invention also improves the impedance bandwidth by loading chamfers on the radiation arms and optimizing the shapes of the feeders and slots.

[0056] Compared with the prior art, the present invention achieves a smaller size and a wider frequency band coverage through a simple and ingenious structure, and can generate an omnidirectional radiation pattern within the operating frequency band. While reducing the production cost, the present invention improves the antenna performance, has high gain and high radiation efficiency, is an ideal choice for ultra-wideband applications, better realizes the combination of ultra-wideband technology and massive multiple-input multiple-output technology, and has broad market prospects.

[0057] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. A ultra-wideband three-port MIMO antenna, characterized in that, It includes a dielectric plate, a first radiation arm, a second radiation arm, a first feeder, a second feeder and a third feeder; The dielectric plate is disposed in the XOY plane. The first radiation arm, the second feeder and the third feeder are printed on the upper surface of the dielectric plate, and the second radiation arm and the first feeder are printed on the lower surface of the dielectric plate; The first radiation arm and the second radiation arm are integrally rectangular. The first radiation arm covers half of the upper surface of the dielectric plate near the negative X-axis direction, and the second radiation arm covers half of the lower surface of the dielectric plate near the positive X-axis direction. The covering areas of the first radiation arm and the second radiation arm on the dielectric plate do not overlap; a first circular slot is etched on the first radiation arm, and a second circular slot is etched on the second radiation arm; The third feeder is arranged parallel to the X-axis. One end of the third feeder is electrically connected to the first radiation arm, and the other end of the third feeder is disposed above the second radiation arm; a through circular hole is formed at the position of the dielectric plate corresponding to the other end of the third feeder to form a first input port; The first input port is fed by a coaxial cable. The coaxial cable is introduced from below the dielectric plate. The outer conductor of the coaxial cable is electrically connected to the second radiation arm, and the inner conductor of the coaxial cable passes through the circular hole and is electrically connected to the other end of the third feeder; The first feeder and the second feeder are arranged parallel to the Y-axis; one end of the first feeder is disposed at the edge of the dielectric plate near the negative Y-axis direction to form a second input port, and the other end of the first feeder is disposed below the middle part of the first radiation arm; one end of the second feeder is disposed at the edge of the dielectric plate near the positive Y-axis direction to form a third input port, and the other end of the second feeder is disposed below the middle part of the second radiation arm.

2. The ultra-wideband three-port MIMO antenna according to claim 1, wherein The second input port is connected and fed to an external coaxial cable through a first SMA interface. The first SMA interface is welded to the side surface of the dielectric plate corresponding to the position of the second input port. The inner pin of the first SMA interface is electrically connected to the first feeder, and the external metal of the first SMA interface is electrically connected to the first radiation arm; The third input port is connected and fed to an external coaxial cable through a second SMA interface. The second SMA interface is welded to the side surface of the dielectric plate corresponding to the position of the third input port. The inner pin of the second SMA interface is electrically connected to the second feeder, and the external metal of the second SMA interface is electrically connected to the second radiation arm.

3. The ultra-wideband three-port MIMO antenna according to claim 2, wherein, The first circular slot includes a first circular groove, a first rectangular groove and a first circular notch groove. The first circular groove is etched near the middle part of the first radiation arm. The first circular notch groove is etched on the side of the first radiation arm near the negative X-axis direction. The first rectangular groove extends along the X-axis direction and connects the first circular groove and the first circular notch groove; A first circular metal patch is connected to the other end of the first feeder for optimizing impedance matching; the first circular metal patch partially overlaps with the first circular groove for coupled feeding.

4. The ultra-wideband three-port MIMO antenna according to claim 3, characterized in that, The second circular slot includes a second circular groove, a second rectangular groove, and a second circular notch groove. The second circular groove is etched near the middle of the second radiating arm, the second circular notch groove is etched at the side of the second radiating arm near the positive X-axis direction, and the second rectangular groove extends along the X-axis direction and connects the second circular groove and the second circular notch groove; The other end of the second feeder is connected with a second circular metal patch for optimizing impedance matching; the second circular metal patch partially overlaps with the second circular groove for coupled feeding.

5. The ultra-wideband three-port MIMO antenna according to claim 2, characterized in that, Chamfers are loaded at the four corners of the first radiating arm and the second radiating arm for expanding the bandwidth of the antenna.

6. The ultra-wideband three-port MIMO antenna according to claim 2, characterized in that, The third feeder is triangular pyramid-shaped for optimizing impedance matching; the end of the third feeder facing the first radiating arm is larger than the end facing the second radiating arm.

7. The ultra-wideband three-port MIMO antenna according to claim 2, characterized in that, The first circular slot and the second circular slot are symmetric about the center of the dielectric substrate, and the first feeder and the second feeder are symmetric about the center of the dielectric substrate.

8. The ultra-wideband three-port MIMO antenna according to claim 2, characterized in that The size of the first circular slot is exactly the same as that of the second circular slot, and the size of the first feeder is exactly the same as that of the second feeder.

9. The ultra-wideband three-port MIMO antenna according to claim 2, characterized in that, The first circular slot is arranged at a position slightly deviated from the middle of the first radiating arm towards the negative Y-axis direction, and the second circular slot is arranged at a position slightly deviated from the middle of the second radiating arm towards the positive Y-axis direction to obtain better impedance matching and circularity.

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