Differential mutual coupling removal antenna based on staggered arrangement double strips

Abstract

In a top metal layer, two rectangular metal patches are distributed side by side, and the two metal strips are horizontally arranged above and below the rectangular metal patches respectively and are arranged in parallel in a staggered mode to form a decoupling structure. The inner cores of the four coaxial feed probes are vertically inserted upwards from the lower part of the bottom metal ground and are correspondingly connected with one rectangular metal patch in pairs; and the two feed probes connected with the same rectangular metal patch respectively form a pair of differential ports. According to the invention, the strips parallel to the two patch units are arranged on the two patch units in the up-down staggered manner, and the arrangement direction of the strips is consistent with that of the differential ports, so that a weak field is generated on the mutual coupling patch, and mutual coupling removal of the differential antenna is realized. Such a staggered arrangement obtains relatively high isolation in a relatively compact case. Meanwhile, the size of the antenna is small, and the ECC level is also reduced.

Description

Technical Field

[0001] The invention relates to an antenna for wireless communication, in particular to a differential decoupling antenna. Background Art

[0002] Differential antennas have better performance stability, reduce performance fluctuations caused by structural asymmetry, and have strong anti-interference ability, which enhances the transmission efficiency of differential mode signals, thereby improving the anti-interference ability of signals. Nowadays, with the rapid development of wireless communications, equipment miniaturization has become an inevitable trend, and the necessity of closely arranged multi-unit patch antenna arrays has become increasingly prominent. However, when differential antennas are closely arranged to save space, mutual interference between antennas will bring many adverse effects, such as poor matching, directional pattern distortion, and reduced radiation performance. Therefore, the existing decoupling technology is mostly applied to single-fed antennas, which can reduce the coupling between single-fed antennas to a certain extent, but cannot be directly used for differentially fed antennas. Because differentially fed antennas have many feeding ports and complex coupling paths. Therefore, it is necessary to explore methods to reduce the mutual coupling between units of multi-unit differential antenna arrays.

[0003] The prior art proposes to achieve high decoupling characteristics through the decoupling network method, but its structural complexity, radiator size and center spacing are still insufficient in large-scale MIMO systems, and it is difficult to meet the needs of compact antenna arrays. In order to reduce the complexity of the antenna structure, the prior art achieves low mutual coupling and consistent radiation pattern characteristics through the characteristic mode and H-shaped structure method, but its structural complexity still needs to be optimized, and the center spacing and radiator size of the radiator are still large, which still cannot meet the needs of compact antenna arrays.

[0004] In summary, these existing methods are difficult to reduce the size of the radiator, the center distance between the radiators, and reduce the structural complexity while achieving low mutual coupling. Summary of the invention

[0005] Purpose of the invention: In view of the above-mentioned prior art, a differential decoupling antenna based on staggered double strips is proposed to simplify the structure, reduce the center distance between radiators and the size of the radiators, and achieve decoupling of the radiation pattern.

[0006] Technical solution: A differential decoupling antenna based on staggered double strips, including a top metal layer, an intermediate dielectric substrate, a bottom metal ground and a feeding structure; The top metal layer includes two rectangular metal patches and two metal strips; the two rectangular metal patches are arranged side by side; the two metal strips are arranged horizontally above and below the rectangular metal patches, respectively, and the two metal strips are parallel to each other and staggered by a certain length to form a decoupling structure; The feeding structure includes four coaxial feeding probes; the inner cores of the coaxial feeding probes are respectively inserted vertically upward from below the bottom metal ground and are pairwise connected to a rectangular metal patch, and the feeding points are all located on the horizontal symmetry axis of the patch; the two feeding probes connected to the same rectangular metal patch respectively form a pair of differential ports.

[0007] Further, the left end of the upper metal strip is relatively located between the left edge of the left metal patch and the outer feeding point of the patch, and the right end of the upper metal strip is relatively located between the two feeding points of the right metal patch; the left end of the lower metal strip is relatively located between the two feeding points of the left metal patch, and the right end of the lower metal strip is relatively located between the right edge of the right metal patch and the outer feeding point of the patch.

[0008] Further, the two rectangular metal patches have the same size, with the length between 0.22λ 0 ~0.28λ 0 and the width between 0.22λ 0 ~0.28λ 0 ; the distance between the two rectangular metal patches is between 0.022λ 0 ~0.028λ 0 ; where λ 0 is the free space wavelength corresponding to the center frequency.

[0009] Further, the center distance between the feeding points of the two coaxial feeding probes on the same rectangular metal patch is between 0.052λ 0 ~0.057λ 0 .

[0010] Further, the two metal strips have the same size, with the length between 0.35λ 0 ~0.40λ 0 and the width between 0.010λ 0 ~0.020λ 0 .

[0011] Further, the distances from the two metal strips to the upper and lower sides of the rectangular metal patch are the same, both between 0.01λ 0 ~0.02λ 0 .

[0012] Beneficial effects: The existing differential decoupling antenna radiator has a large size and a complex structure, resulting in a large center spacing between radiator units and a large radiator size. In the present invention, strips parallel to each other are arranged in a vertically staggered manner on two patch units, and the strips are arranged in the same direction as the differential ports, forming an asymmetric structure, thereby generating a weak field on the coupled patch and realizing the decoupling of the differential antenna. Such a staggered arrangement achieves a relatively high isolation in a relatively compact situation. At the same time, the size of the antenna is relatively small, and the level of ECC (Envelope Correlation Coefficient) is also reduced. Description of the Drawings

[0013] Figure 1 It is a schematic cross-sectional structure diagram of the differential decoupling patch antenna of the present invention; Figure 2 It is a schematic top view structure diagram of the differential decoupling patch antenna of the present invention; Figure 3 It is a schematic bottom view structure diagram of the differential decoupling patch antenna of the present invention; Figure 4 It is the simulation result of the differential decoupling patch antenna in the embodiment, where (a) is the S parameter and (b) is the gain curve; Figure 5 It is the simulation radiation pattern of the differential decoupling patch antenna in the embodiment at 3.47 GHz. Detailed Embodiment

[0014] The present invention will be further explained below with reference to the drawings.

[0015] As Figure 1 shown, a differential decoupling antenna based on a staggered arrangement of double strips is composed of a top metal layer 1, an intermediate dielectric substrate 2, a bottom metal ground 3, and a feeding structure 4.

[0016] As Figure 2 shown, the top metal layer 1 is located on the upper surface of the intermediate dielectric substrate 2 and is composed of rectangular metal patches 11 and 12, and metal strips 13 and 14. The rectangular metal patches 11 and 12 are arranged side by side, and the mutually staggered parallel metal strips 13 and 14 are respectively arranged above and below the rectangular metal patches 11 and 12, making the top metal layer form a left-right asymmetric structure.

[0017] As Figure 1 、 Figure 3As shown, the feeding structure 4 is composed of coaxial feeding probes 41 to 44. The inner cores of the coaxial feeding probes 41 and 42 are vertically inserted upward from below the bottom metal ground 3 and connected to the rectangular metal patch 11, and the feeding points are located on the horizontal symmetry axis of the patch. The inner cores of the coaxial feeding probes 43 and 44 are vertically inserted upward from below the bottom metal ground 3 and connected to the rectangular metal patch 12, and the feeding points are also located on the horizontal symmetry axis of the patch. The coaxial feeding probes 41 and 42 form a pair of differential ports, and the coaxial feeding probes 43 and 44 also form a pair of differential ports. The feeding points of the coaxial feeding probes 41 and 44 are located on the relatively outer sides.

[0018] The left end of the metal strip 13 is relatively located between the left edge of the metal patch 11 and the feeding point of the coaxial feeding probe 41, and the right end of the metal strip 13 is relatively located between the feeding points of the coaxial feeding probes 43 and 44; the left end of the metal strip 14 is relatively located between the feeding points of the coaxial feeding probes 41 and 42, and the right end of the metal strip 14 is relatively located between the right edge of the metal patch 12 and the feeding point of the coaxial feeding probe 44.

[0019] In the above structure, the rectangular metal patches 11 and 12 form a radiation structure; the metal strips 13 and 14 form a decoupling structure.

[0020] The rectangular metal patches 11 and 12 have the same size. Their length (in the y-axis direction) is between 0.22λ 0 ~0.28λ 0 and their width (in the x-axis direction) is between 0.22λ 0 ~0.28λ 0 ; the distance between the rectangular metal patches 11 and 12 is between 0.022λ 0 ~0.028λ 0 ; the center distance between the feeding points of the two coaxial feeding probes on the same rectangular metal patch is between 0.052λ 0 ~0.057λ 0 ; the metal strips 13 and 14 have the same size. The length is between 0.35λ 0 ~0.40λ 0 and the width is between 0.010λ 0 ~0.020λ 0 ; the distances from the metal strips 13 and 14 to the upper and lower sides of the rectangular metal patches 11 and 12 are the same, both between 0.01λ 0 ~0.02λ 0 ; where λ 0 is the free space wavelength corresponding to the center frequency.

[0021] Differential excitation generates signals with equal amplitude and opposite directions, which are fed into the rectangular metal patch 11 through the differential ports formed by the coaxial feeding probes 41 and 42, thereby generating TM10 modes and radiate outward. In addition, due to the asymmetric arrangement structure of the metal strips 13 and 14, weak field regions are simultaneously generated at the positions of the feeding points on the rectangular metal patch 12 that is mutually coupled with the rectangular metal patch 11. At this time, the energy of the weak field regions cannot be transmitted downward to the differential ports formed by the coaxial feeding probes 43 and 44, so that the differential ports cannot be excited, thereby achieving a good isolation characteristic.

[0022] In this embodiment, the material of the dielectric substrate is Rogers RO4003C, its dielectric constant is 3.55, and the loss tangent is 0.0027. The lengths of the rectangular metal patches 11 and 12 are 0.25λ 0 and the widths are also 0.25λ 0 ; the distance between the rectangular metal patches 11 and 12 is 0.025λ 0 . The center distance between the feeding points of the two coaxial feeding probes on the same rectangular metal patch is 0.054λ 0 . The metal strips 13 and 14 have the same size, the length is 0.37λ 0 and the width is 0.015λ 0 . The distances from the metal strips 13 and 14 to the upper and lower sides of the rectangular metal patches 11 and 12 are both 0.014λ 0 . The simulation results of the antenna's matching, isolation, and gain response are as Figure 4 shown. The 10-dB impedance matching bandwidth of this embodiment is 2.4%, the maximum gain within the operating frequency band is 4.83 dB, and the isolation is greater than 29.06 dB at 3.47 GHz. Figure 5 is the simulated E-plane radiation pattern of the antenna in this embodiment at 3.47 GHz. The 3-dB beamwidth in the E-plane is 121.8°. At this frequency point, the cross-polarization level within the 3-dB beamwidth in the E-plane is -12 dB. Compared with the existing differential patch antenna decoupling technology, the present invention reduces the radiator size, the center distance of the radiators, and the structural complexity through the structure of misaligned double strips, and also reduces the ECC.

[0023] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A differential decoupling antenna based on staggered double strips, characterized in that: It includes a top metal layer, an intermediate dielectric substrate, a bottom metal ground and a feeding structure; The top metal layer includes two rectangular metal patches and two metal strips; the two rectangular metal patches are arranged side by side; the two metal strips are arranged horizontally above and below the rectangular metal patches, respectively, and the two metal strips are parallel to each other and staggered by a certain length to form a decoupling structure; The feeding structure includes four coaxial feeding probes; the inner cores of the coaxial feeding probes are inserted vertically upward from the bottom metal ground and connected to a rectangular metal patch in pairs, and the feeding points are all located on the horizontal symmetry axis of the patch; the two feeding probes connected to the same rectangular metal patch respectively form a pair of differential ports.

2. The differential decoupling antenna according to claim 1, characterized in that: The left end of the upper metal strip is relatively located between the left edge of the left metal patch and the outer feeding point of the patch, and the right end of the upper metal strip is relatively located between the two feeding points of the right metal patch; the left end of the lower metal strip is relatively located between the two feeding points of the left metal patch, and the right end of the lower metal strip is relatively located between the right edge of the right metal patch and the outer feeding point of the patch.

3. The differential decoupling antenna according to claim 1 or 2, characterized in that: The two rectangular metal patches have the same size, with a length between 0.22λ0 and 0.28λ0 and a width between 0.22λ0 and 0.28λ0; the spacing between the two rectangular metal patches is between 0.022λ0 and 0.028λ0; wherein λ0 is the free space wavelength corresponding to the center frequency.

4. The differential decoupling antenna according to claim 3, characterized in that: The center spacing between the feeding points of two coaxial feeding probes on the same rectangular metal patch is between 0.052λ0 and 0.057λ0.

5. The differential decoupling antenna according to claim 4, characterized in that: The two metal strips have the same size, with a length between 0.35λ0 and 0.40λ0 and a width between 0.010λ0 and 0.020λ0.

6. The differential decoupling antenna according to claim 5, characterized in that: The distances between the two metal strips and the upper and lower sides of the rectangular metal patch are consistent, both between 0.01λ0 and 0.02λ0.

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