Four-port antenna system based on mutual coupling removal structure multiplexing

Abstract

The invention discloses a four-port antenna system based on multiplexing of a mutual coupling removing structure, which is characterized in that on the premise of realizing excellent circular polarization mutual coupling removing performance of a dielectric resonator antenna, a part of mutual coupling removing structure of a 1 * 2 circular polarization antenna array is multiplexed as an additional monopole antenna, and a feed network is introduced for effective excitation, so that the coupling removing performance of the dielectric resonator antenna is improved; therefore, two additional monopole antennas are obtained, the monopole antennas and an original circularly polarized antenna can work independently, and the antennas have good isolation characteristics. Based on this, a novel four-port antenna system is realized on the premise of keeping the aperture of the original 1 * 2 circularly polarized antenna array unchanged, the four-port antenna system comprises two circularly polarized antennas and two monopole antennas, and the design has better system capacity or more communication functions compared with the existing circularly polarized cross-coupling removal antenna design.

Description

Technical Field

[0001] This invention relates to a microwave communication device, and more particularly to a circularly polarized dielectric resonator antenna. Background Technology

[0002] Circularly polarized antennas offer advantages over linearly polarized antennas, including suppressing multipath reflection interference, reducing polarization mismatch, and overcoming the Faraday rotation effect, leading to their widespread application in satellite communications and global positioning systems. MIMO antenna technology can effectively improve the channel capacity and transmission rate of communication systems. However, as antenna systems evolve towards miniaturization and integration, MIMO multi-antenna systems need to be implemented in a more compact form. The dense arrangement of circularly polarized antennas inevitably leads to severe mutual coupling problems. Therefore, decoupling techniques for circularly polarized antennas have recently become a hot research topic in the antenna field.

[0003] Existing circularly polarized antenna decoupling techniques can be broadly categorized into three types: The first type, such as EBG and DGS techniques, achieves decoupling by directly blocking electromagnetic wave propagation; the second type achieves decoupling between elements by constructing a current path opposite to the coupling field, thus canceling out the original coupling field current, for example, by introducing parasitic elements or adding neutralization lines; the third type is an antenna that achieves decoupling functionality through its own structural design, such as a decoupling network or a self-decoupling structure.

[0004] In existing multiport antenna technologies, to suppress the mutual coupling effects between ports, most common research methods rely on introducing independent decoupling structures. These methods include adding physical isolation walls between antenna elements, loading passive parasitic elements or metal decoupling pillars, and etching decoupling slots of specific shapes onto the ground plane. This design approach has a common limitation: these independent decoupling structures only perform the decoupling function and do not participate in the radiation process. The antenna aperture utilization rate is not improved, and the number of radiating ports cannot be increased within the same aperture area, thus limiting the expansion of system capacity and the realization of multi-functional communication capabilities.

[0005] Therefore, how to achieve the integration of decoupling structure and radiation function within a limited space, and improve the structural reuse rate and aperture efficiency, has become a key technical challenge that urgently needs to be overcome in the field of multi-port antenna design. Summary of the Invention

[0006] Purpose of the invention: To address the aforementioned prior art, a four-port antenna system based on decoupling structure multiplexing is proposed.

[0007] Technical solution: A four-port antenna system based on decoupling structure multiplexing includes two rectangular dielectric blocks arranged in a 1×2 configuration on a metal ground plane, and a dielectric substrate and a feed port structure are stacked sequentially under the metal ground plane. The rectangular dielectric block has metal strips on its side perpendicular to the metal ground plane, which serve as a decoupling structure for the circularly polarized dielectric resonator antenna. One set of diagonal metal strips is multiplexed as a monopole antenna radiator. The metal ground plane is provided with coupling slots that are respectively facing each rectangular medium block; The feed port structure includes the feed port of a 1×2 circularly polarized dielectric resonator and the feed port of the monopole antenna.

[0008] Furthermore, metal strips are provided on the four sides of the rectangular dielectric block, and a set of diagonal metal strips are separated by gaps into an unreused upper metal strip and a lower metal strip that is reused as a monopole antenna radiator.

[0009] Furthermore, the coupling gap is a cross-shaped gap, and the cross axis is directly opposite the diagonal of the rectangular dielectric block, which is used to realize the circular polarization excitation of the dielectric resonator antenna.

[0010] Furthermore, the feed port of the 1×2 circularly polarized dielectric resonator includes two cross-shaped microstrip feed lines.

[0011] Furthermore, the feed port of the monopole antenna includes a 1 / 2 Wilkinson power divider with equal phase; the dielectric substrate and the metal ground plane are provided with through holes facing the monopole antenna radiators, and the two ports of the Wilkinson power divider are respectively connected to the two monopole antenna radiators at opposite corners of the rectangular dielectric block through circular metal pillars passing through the through holes.

[0012] Furthermore, one end of the cross-shaped microstrip feed line is located on the upper side of the dielectric substrate, and the other end extends beyond the center point of the cross-shaped slot.

[0013] Furthermore, the single port of the Wilkinson power divider is located on the lower side of the dielectric substrate.

[0014] Furthermore, the two circularly polarized antennas and two monopole antennas of the four-port antenna system all operate in the S-band.

[0015] Furthermore, the metal strip achieves decoupling by changing the polarization of the coupling electric field between the dielectric resonator units.

[0016] Beneficial Effects: This invention, while achieving excellent circular polarization decoupling performance of the dielectric resonator antenna, cleverly reuses part of the decoupling structure of a 1×2 circularly polarized antenna array as an additional monopole antenna. By introducing a feeding network for effective excitation, two additional monopole antennas are obtained. These monopole antennas can operate independently of the original circularly polarized antennas, and each antenna exhibits good isolation characteristics. Based on this, this invention realizes a novel four-port antenna system, comprising two circularly polarized antennas and two monopole antennas, while maintaining the original 1×2 circularly polarized antenna array aperture. This design offers superior system capacity or more communication functions compared to existing circularly polarized decoupling antenna designs.

[0017] The four-port antenna system of this invention comprises two circularly polarized antennas and two monopole antennas, all operating in the S-band (2GHz~4GHz), and can be widely used in 5G communication, satellite communication, and radar systems. Without increasing the antenna aperture, it successfully achieves coordinated operation and high isolation characteristics of the dielectric resonator antenna and the monopole antenna at the same center frequency (2.8GHz). Attached Figure Description

[0018] Figure 1 This is an exploded structural diagram of the antenna system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the port distribution of the antenna system according to an embodiment of the present invention; Figure 3 The results are the S-parameter simulations when only the dielectric resonator antenna is excited. Figure 4 Simulation results for the axial ratio and gain of the dielectric resonator antenna; Figure 5 The simulated antenna radiation pattern of the dielectric resonator antenna at 2.8 GHz is shown. Figure 6 The simulation results are for the reflection coefficient and gain of a monopole antenna that is only excited. Figure 7 The image shows the simulated radiation pattern of a monopole antenna at 2.8 GHz. Detailed Implementation

[0019] The invention will now be further explained with reference to the accompanying drawings.

[0020] This invention is based on a dielectric resonator antenna (DRA). While ensuring excellent circular polarization radiation and decoupling performance of the 1×2 circularly polarized antenna array, it employs a clever structural reuse design: circularly polarized waves are excited by etching oblique cross-shaped slots on the antenna ground plane, and the radiation effect is enhanced by using cross-shaped microstrip feed lines. At the same time, four metal strips are introduced on the side of each DRA perpendicular to the substrate, so that the coupling electric field of the dielectric resonator antenna is transformed into circular polarization opposite to the excitation electric field, effectively improving the array's decoupling effect. On this basis, some of the decoupling metal strips are reused as radiators of monopole antennas, and an independent feed channel is formed by integrating Wilkinson power dividers, enabling them to work simultaneously with the original circularly polarized antennas without interference, further realizing the expansion of two additional monopole antennas in the original array structure.

[0021] like Figure 1 , Figure 2 As shown, the layer structure of a four-port antenna system based on decoupling structure multiplexing in this embodiment specifically includes, from top to bottom: The first layer consists of 1×2 rectangular dielectric blocks 1. Metal strips 2 are provided on the four vertical sides of the rectangular dielectric blocks 1. One set of diagonal metal strips 2 is separated by gaps into an unreused upper metal strip 3 and a lower metal strip 4 reused as a monopole antenna radiator.

[0022] The second layer is a metal ground plane 5, on which two pairs of first circular through holes 6 and two cross-shaped slots 7 are etched. The two cross-shaped slots 7 are located directly below the two rectangular dielectric blocks 1, and the cross axes are directly opposite the diagonal lines of the rectangular dielectric blocks 1. The four first circular through holes 6 are directly opposite the lower metal strip 4 that is used as the radiator of the monopole antenna. The cross-shaped slots 7 and the first circular through holes 6 are used to realize the circular polarization excitation of the dielectric resonator antenna and the feeding of the monopole antenna to the radiator.

[0023] The third layer is a dielectric substrate 8, on which two pairs of second circular through holes 10 are formed. The second circular through holes 10 are respectively opposite to each of the first circular through holes 6, and a circular metal post 9 is provided in the second circular through hole 10. The circular metal post 9 passes upward through the first circular through hole 6 and connects to each of the lower metal strips 4 to realize the port connection.

[0024] The fourth layer is the feed port structure, including two dielectric resonator antenna feed ports Port1 and Port2, which are respectively composed of cross-shaped microstrip feed lines 13, and two monopole antenna feed ports Port3 and Port4, which are respectively composed of isolation resistor 11 and Wilkinson power divider 12. One end of the cross-shaped microstrip feed line 13 is located on the upper side of the dielectric substrate 8, and the other end extends beyond the center point of the cross-shaped slot 7. The single port of the Wilkinson power divider 12 is located on the lower side of the dielectric substrate 8, and the dual ports of the Wilkinson power divider 12 are located directly below a pair of second circular through holes 10, and are connected to the circular metal pillars 9 inside the second circular through holes 10.

[0025] The four-port antenna system described above feeds a rectangular dielectric block 1 above it via a cross-shaped microstrip feed line 13 through a cross-shaped slot 7 on a metal ground plane 5, thereby exciting a continuously rotating circularly polarized electromagnetic field inside the dielectric resonator. At the same time, metal strips 2 are introduced as decoupling structures on the four sides of each rectangular dielectric block 1 perpendicular to the dielectric substrate 8. By changing the polarization of the coupling electric field between the dielectric resonator units, the port isolation of the dielectric resonator antenna in the 2.8 GHz operating frequency band is effectively improved, and good circular polarization performance (axial ratio <3dB) is maintained in this frequency band. Furthermore, by using a structural reuse method, the dielectric resonator antenna is used as part of the decoupling structure, with the metal strip 4 serving as the radiator of the monopole antenna. It is connected to the equi-phase 1 / 2 Wilkinson power divider 12 through a circular metal pillar 9 that penetrates the metal ground plane 5 and the dielectric substrate 8, thereby feeding the monopole antenna radiator. This ensures that the monopole antenna operates normally in the 2.8 GHz band while maintaining good high isolation from the dielectric resonator antenna, without affecting the decoupling effect and circular polarization radiation performance of the dielectric resonator antenna.

[0026] This invention is a four-port antenna system based on decoupling structure multiplexing, and its specific port distribution is as follows: Figure 2 As shown. The dielectric substrate 8 used has a dielectric constant of 3.38, a loss tangent of 0.0035, and a thickness of 1.57 mm; the base dimension of the rectangular dielectric block 1 is 27 mm × 27 mm (~0.25 × 0.25λ0). 2 @2.8GHz), with a height of 31mm (~0.29λ0@2.8GHz); the metal strip 2 on the rectangular dielectric block 1 has a width of 1.1mm, and a set of diagonally opposite metal strips 2 are separated by a gap of 1.14mm into an unreused upper metal strip 3 and a lower metal strip 4 reused as a monopole antenna radiator, respectively. The length of the lower metal strip 4 is 11mm. When only the dielectric resonator antenna is excited, its transmission response, axial ratio, and gain characteristics are as follows: Figure 3 and Figure 4As shown, under the condition that the reflection coefficient S11 ≤ -10 dB, the impedance bandwidth is 2.75 GHz to 2.85 GHz. At the center frequency of 2.8 GHz, S21, S31 and S41 are -28.26 dB, -36.23 dB and -31.03 dB, respectively. The axial ratio bandwidth is 2.77 GHz to 2.84 GHz, and the average gain within the operating frequency band is higher than 4.5 dBi. Figure 5 Simulated radiation pattern of dielectric resonator antenna at 2.8 GHz is presented, with cross-polarization suppression better than 15 dB.

[0027] When only a monopole antenna is excited, its transmission response and gain characteristics are as follows: Figure 6 As shown, the operating bandwidth range is 2.74 GHz to 2.86 GHz. At the center frequency of 2.8 GHz, the antenna's S13, S23, and S43 are all below -27 dB, and its average in-band gain is above 4.5 dBi. Figure 7 The simulated radiation pattern of the monopole antenna at 2.8 GHz shows that its cross-polarization level is better than 15 dB, indicating that the proposed structure maintains good radiation performance while achieving high isolation.

[0028] Compared to existing circularly polarized dielectric resonator antennas and decoupling schemes, traditional methods improve isolation by adding independent structures such as isolation walls and parasitic elements, which not only occupy additional space and increase system complexity but also fail to improve antenna port density and system functionality. This invention employs partial structure reuse technology, reusing a portion of a set of diagonal metal strips on the side of the dielectric resonator used for decoupling as the radiator of a monopole antenna. Without changing the original 1×2 array aperture, it not only maintains the excellent circular polarization characteristics and high port isolation of the dielectric resonator antenna but also gains two additional independently operating linearly polarized communication channels, enabling multi-mode collaborative operation within a single aperture. This structure-reused four-port system significantly improves space utilization while maintaining high isolation between antenna ports. The operating center frequencies of both the dielectric resonator antenna and the monopole antenna in the system are 2.8 GHz. When any port is excited, the isolation of the remaining ports is better than 25 dB. Furthermore, when the dielectric resonator antenna is excited, the axial ratio remains stably below 3 dB within the operating frequency band, and each antenna exhibits excellent radiation performance.

[0029] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A four-port antenna system based on decoupling structure multiplexing, characterized in that, It includes two rectangular dielectric blocks (1) arranged in a 1×2 configuration on a metal ground plane (5), and a dielectric substrate (8) and a power supply port structure are stacked sequentially below the metal ground plane (5); The rectangular dielectric block (1) has metal strips (2) on the side perpendicular to the metal ground plane (5) as a decoupling structure for a circularly polarized dielectric resonator antenna, wherein a set of diagonally opposite metal strips (2) are multiplexed as monopole antenna radiators. The metal ground plate (5) is provided with coupling gaps facing each rectangular medium block (1); The feed port structure includes the feed port of a 1×2 circularly polarized dielectric resonator and the feed port of the monopole antenna.

2. The four-port antenna system according to claim 1, characterized in that, Metal strips (2) are provided on the four sides of the rectangular dielectric block (1). A set of diagonal metal strips (2) are separated by gaps into an unreused upper metal strip (3) and a lower metal strip (4) reused as a monopole antenna radiator.

3. The four-port antenna system according to claim 1, characterized in that, The coupling gap is a cross-shaped gap (7), and the cross axis is directly opposite the diagonal of the rectangular dielectric block (1), which is used to realize the circular polarization excitation of the dielectric resonator antenna.

4. The four-port antenna system according to claim 3, characterized in that, The feed port of the 1×2 circularly polarized dielectric resonator includes two cross-shaped microstrip feed lines (13).

5. The four-port antenna system according to claim 3, characterized in that, The feed port of the monopole antenna includes a 1 / 2 Wilkinson power divider (12) with equal phase; the dielectric substrate (8) and the metal ground plane (5) are provided with through holes facing the monopole antenna radiators, and the two ports of the Wilkinson power divider (12) are respectively connected to the two monopole antenna radiators on opposite corners of the rectangular dielectric block (1) through circular metal pillars (9) passing through the through holes.

6. The four-port antenna system according to claim 5, characterized in that, One end of the cross-shaped microstrip feed line (13) is located on the upper side of the dielectric substrate (8), and the other end extends beyond the center point of the cross-shaped slot (7).

7. The four-port antenna system according to claim 6, characterized in that, The single port of the Wilkinson power divider (12) is located on the lower side of the dielectric substrate (8).

8. The four-port antenna system according to any one of claims 1-7, characterized in that, The two circularly polarized antennas and two monopole antennas of the four-port antenna system all operate in the S-band.

9. The four-port antenna system according to any one of claims 1-7, characterized in that, The metal strip (2) achieves decoupling by changing the polarization of the coupling electric field between the dielectric resonator units.

Images