Self-decoupling patch antenna based on slot

Abstract

The invention discloses a self-decoupling patch antenna based on a groove. The self-decoupling patch antenna comprises a top layer metal structure, an upper layer dielectric substrate, a lower layer dielectric substrate, a metal ground layer and a coaxial line. According to the self-decoupling patch antenna, the rectangular grooves are symmetrically embedded in the vertical symmetry axis of the rectangular metal patch, the oblique current of the coupling unit is constructed by using the change of the rectangular groove of the excitation unit on the current distribution, and the self-decoupling of the patch antenna is realized by combining the expansion effect of the rectangular groove of the coupling unit on the weak electric field area; the problem of limitation of a self-decoupling antenna structure on decoupling spacing is solved, conventional spacing array arrangement and decoupling are realized, and relatively wide matching and decoupling bandwidths are considered.

Description

TECHNICAL FIELD

[0001] The present application relates to a wireless communication device, in particular to a self-decoupling patch antenna. BACKGROUND

[0002] Patch antennas usually need to be arranged in an array to improve the antenna gain and thus enhance the coverage distance. However, the small spacing between the units will cause coupling, leading to deterioration of the active impedance matching of the patch antenna array, distortion of the radiation pattern, and poor linear polarization effect, which seriously restricts the application potential of the patch antenna array in the system, and thus the patch antenna array needs to be decoupled. The self-decoupling technology is one of the antenna decoupling technologies, and compared with other decoupling technologies, the self-decoupling technology relies on the structural characteristics to achieve decoupling without additional decoupling structure, and has the characteristics of simple structure, easy to arrange, low design complexity, and low cost. Therefore, it is necessary to explore and propose patch antenna self-decoupling related technologies and methods.

[0003] There are mainly two kinds of existing patch antenna self-decoupling technologies. The first kind is to use closely arranged patch antennas, use the electric and magnetic coupling characteristics of the sub-regional coupling, adjust the weights of the electric and magnetic coupling, and realize the coupling cancellation on the adjacent units, but it can only be applied to the closely arranged scenario and cannot be applied to the patch antenna array with normal arrangement spacing. The second kind is to increase the aspect ratio of the patch and embed double slots on both sides to realize the low cross-polarization and low mutual coupling patch antenna array with regular spacing arrangement in the E plane, wherein the increase of the aspect ratio of the patch can reduce the mutual coupling, and the embedding of the double slots can reduce the cross-polarization, but the H plane array arrangement is limited by the aspect ratio of the patch, which reduces the freedom of array arrangement, and the matching and decoupling bandwidth is narrow. SUMMARY

[0004] The present application aims to provide a slot-based self-decoupling patch antenna, which can realize regular spacing array arrangement and decoupling, and can also consider a relatively wide matching and decoupling bandwidth.

[0005] The technical scheme is as follows: a slot-based self-decoupling patch antenna, comprising a top metal structure, an upper dielectric substrate, a lower dielectric substrate, a metal ground layer, and a coaxial line; the top metal structure is located on the upper surface of the upper dielectric substrate and comprises two rectangular metal patches arranged side by side with a spacing, and a rectangular slot is arranged on the vertical symmetry axis of the rectangular metal patch; an air layer is arranged between the lower dielectric substrate and the upper dielectric substrate; the metal ground layer is located on the lower surface of the lower dielectric substrate; the coaxial line is used as a feeding structure, the inner conductors of the two coaxial lines pass through the circular holes on the metal ground layer and the lower dielectric substrate and the upper dielectric substrate, and are connected to the two rectangular metal patches, respectively, and the feeding points are located on the vertical symmetry axes of the rectangular metal patches.

[0006] Further, the length of the rectangular slot is between 0.14λ0~0.15λ0, and the width is between 0.05λ0~0.06λ0, λ0 is the free space wavelength corresponding to the center frequency.

[0007] Further, the length of the rectangular metal patch is between 0.39λ0~0.40λ0, and the width is between 0.37λ0~0.38λ0.

[0008] Further, the thickness of the air layer is between 0.07λ0~0.08λ0.

[0009] Further, the two rectangular metal patches are respectively combined with the upper layer dielectric substrate, the lower layer dielectric substrate and the metal ground layer to form two patch antenna units; the change of the current distribution of the rectangular slot of the excitation patch antenna unit is used to construct the oblique current of the coupled patch antenna unit, and the expansion effect of the rectangular slot of the coupled patch antenna unit on the weak electric field region is combined to realize the self-decoupling of the patch antenna.

[0010] Further, the width of the rectangular slot is adjusted to change the frequencies of the matching and mutual coupling zero points, and the matching is obtained by adjusting the position of the feed point along the vertical symmetry axis, and the expanded weak electric field region of the coupled patch antenna unit can cover the position of the feed point.

[0011] Beneficial effect: the existing patch antenna self-decoupling technology has the problem that the array spacing or element margin is limited by the decoupling structure or antenna structure, and some technologies also have the problem of narrow matching and decoupling bandwidth. The self-decoupling patch antenna of the application symmetrically embeds a rectangular slot on the vertical symmetry axis of the rectangular metal patch, uses the change of the current distribution of the excitation unit rectangular slot to construct the oblique current of the coupled unit, combines the expansion effect of the rectangular slot of the coupled unit on the weak electric field region to realize the self-decoupling of the patch antenna, solves the problem of the limitation of the decoupling spacing of the self-decoupling antenna structure, realizes the conventional spacing array arrangement and decoupling, and also considers the relatively wide matching and decoupling bandwidth.

[0012] Wherein, the rectangular slot is symmetrically placed along the vertical symmetry axis of the rectangular metal patch, and the rectangular slot is used to reconstruct the current of the excitation unit and expand the weak electric field region of the coupled unit to realize decoupling. Wherein, the width of the rectangular slot changes the frequencies of the matching and mutual coupling zero points, and the moving speed of the mutual coupling zero point is faster than the matching frequency; the length of the rectangular slot has slight control ability on the depth of the mutual coupling zero point.

[0013] The rectangular metal patch is located on the upper surface of the upper layer dielectric substrate, and there is an air layer between the upper and lower layer dielectric substrates, which is used to reduce the quality factor of the self-decoupling antenna, which is beneficial to expand the matching and decoupling bandwidth. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a cross-sectional structure schematic diagram of the embodiment antenna. Figure 2 This is a top view of the antenna structure in the embodiment. Figure 3 The following is a comparison diagram of the average amplitude electric field before and after the antenna slotting in the embodiment, where (a) corresponds to before slotting and (b) corresponds to after slotting. Figure 4 Examples of antennas under different combinations of structural parameters S The parameter simulation response, where (a) corresponds to | S 11 |,(b) corresponds to| S 21 |; Figure 5 Simulation of the antenna before and after decoupling for the example. S The parameter comparison diagram shows that (a) corresponds to before decoupling and (b) corresponds to after decoupling. Figure 6 The simulated radiation pattern of the antenna in the example is shown, where (a) corresponds to E (b) corresponds to (b) H noodle. Detailed Implementation

[0015] The invention will now be further explained with reference to the accompanying drawings.

[0016] like Figure 1 , Figure 2 As shown, a slot-based self-decoupling patch antenna consists of a top metal structure 1, an upper dielectric substrate 2, a lower dielectric substrate 3, a metal ground layer 4, and two coaxial lines 5.

[0017] The top metal structure 1 is located on the upper surface of the upper dielectric substrate 2, and is composed of two rectangular metal patches 101 with rectangular grooves 102 embedded in them. The two rectangular metal patches 101 are arranged side by side with intervals. The rectangular grooves 102 are located on the vertical axis of symmetry of the rectangular metal patches 101.

[0018] The lower dielectric substrate 3 is positioned directly below the upper dielectric substrate 2, with an air layer between them. A metal ground layer 4 is located on the lower surface of the lower dielectric substrate 3. The metal ground layer 4 is a metal ground plane 402 etched with two circular holes 401. The inner conductors of the two coaxial lines 5, serving as the power supply structure, pass through the circular holes 401, the lower dielectric substrate 3, and the upper dielectric substrate 2 from the bottom surface of the metal ground plane 402, and are connected to two rectangular metal patches 101. The power supply points are located on the vertical axis of symmetry of the rectangular metal patches 101 and below the rectangular groove 102.

[0019] The length (along the Y-axis in the figure) of the rectangular metal patch 101 is between 0.39λ0 and 0.40λ0, and the width (along the X-axis in the figure) is between 0.37λ0 and 0.38λ0. The length of the rectangular groove 102 is between 0.14λ0 and 0.15λ0, and the width is between 0.05λ0 and 0.06λ0, where λ0 is the free-space wavelength corresponding to the center frequency. The air layer thickness is between 0.07λ0 and 0.08λ0.

[0020] In the above structure, the rectangular metal patch 101 with the rectangular slot 102 embedded, the upper dielectric substrate 2, the lower dielectric substrate 3, and the metal ground layer 4 constitute the patch antenna unit.

[0021] For the above-mentioned slot-based self-decoupling patch antenna, the signal is fed into the corresponding patch antenna element from the coaxial line 5. Under the action of the overall patch array embedded with the rectangular slot 102, the radiation and decoupling of the self-decoupling patch antenna array are realized.

[0022] During this process, the rectangular slot 102, while maintaining the polarization and radiation symmetry of the excitation antenna, cuts the current in the middle region of the patch. The current flows around the edge of the slot, changing the current distribution area and density on the surface of the excitation patch. In a Cartesian coordinate system with the geometric center of the excitation patch as the center and the width direction of the rectangular slot 102 as the x-axis and the length direction as the y-axis, the coupling unit exhibits an induced current distribution in the -45° direction. Furthermore, the rectangular slot on the coupling unit expands the weak electric field region along the 45° direction, such as... Figure 3 As shown, the expanded weak electric field region can cover the feed probe of the coupling unit, which significantly weakens the output signal at the feed port of the coupling unit, thus producing a significant port decoupling effect.

[0023] In this invention, the width of the rectangular slot 102 simultaneously alters the frequencies of both the matching and mutual coupling nulls. As the width of the rectangular slot 102 increases, the frequencies shift towards lower frequencies, but the mutual coupling nulls move faster than the matching frequency. Simultaneously, the change in the width of the rectangular slot 102 alters the matching degree, requiring adjustment of the feed point position along the vertical axis of symmetry to re-achieve matching. When the feed point position moves towards the center of the rectangular metal patch 101, the depth of the mutual coupling nulls increases. The length of the rectangular slot 102 has a slight control over the depth of the mutual coupling nulls; as the rectangular slot 102 lengthens, the depth of the mutual coupling nulls first increases and then decreases. Therefore, this invention can achieve self-decoupling of the patch antenna under conditions where the aspect ratio is not large. This is beneficial for overcoming the limitations of self-decoupling antenna structures on decoupling spacing, enabling conventional spacing array arrangement and decoupling, while also balancing relatively wide matching and decoupling bandwidths.

[0024] This embodiment is a 1×2 patch antenna unit structure. The dielectric substrate used is RO4003C with a dielectric constant of 3.55. The electrical dimensions of the antenna are 1.17λ0 × 0.58λ0 × 0.08λ0.Figure 4 For the antenna in this embodiment S The response curves of the parameters under different combinations of structural parameters are shown in the table below. In the table, the distance from the lower edge of the rectangular groove to the center point of the metal patch in Combination 1 is -0.03λ0, indicating that the lower edge of the rectangular groove is below the center point of the metal patch in the figure.

[0025] from Figure 4 From (a), we can know | S 11 |The variation with different combinations of structural parameters is small, while Figure 4 (b) Proof of mutual coupling | S 21 The zero point varies considerably with different combinations of structural parameters, indicating that this technology can control the frequency of the mutually coupled zero point.

[0026] Figure 5 The simulation results of S-parameters before and after antenna decoupling in this embodiment are as follows: Figure 5 As shown in (a) and (b), before decoupling, the -10 dB matching bandwidth of the patch antenna covers 4.22 GHz to 4.42 GHz, with a relative bandwidth of 4.6%. The decoupling level within the matching band is -18.4 dB, the mutual coupling zero deviates from the center frequency of the matching bandwidth by 0.1 GHz, and the overlap bandwidth between the -20 dB decoupling and the -10 dB matching bandwidth is only 2.8%. After decoupling, the -10 dB matching bandwidth of the patch antenna is expanded to 4.23 GHz to 4.53 GHz, with a relative bandwidth of 6.9%. The decoupling level within the matching band is improved to -22.4 dB, the mutual coupling zero corresponds to the center frequency of the matching bandwidth, and the overlap bandwidth between the -20 dB decoupling and the -10 dB matching bandwidth reaches 6.9%. It can be seen that both the matching bandwidth and decoupling capability are significantly improved.

[0027] Figure 6 (a) and (b) show the antenna at 4.37 GHz, respectively. E Face to face H The simulated radiation pattern shows that the maximum radiation pattern of the antenna is positive, the cross-polarization level of the E-plane is -14.6 dB, and the cross-polarization level of the H-plane is -14.9 dB.

[0028] 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 slot-based self-decoupling patch antenna, characterized in that, It includes a top metal structure (1), an upper dielectric substrate (2), a lower dielectric substrate (3), a metal ground layer (4), and a coaxial cable (5); The top metal structure (1) is located on the upper surface of the upper dielectric substrate (2) and includes two rectangular metal patches (101) arranged side by side and spaced apart. A rectangular groove (102) is provided on the vertical axis of symmetry of the rectangular metal patch (101). An air layer is provided between the lower dielectric substrate (3) and the upper dielectric substrate (2); a metal ground layer (4) is located on the lower surface of the lower dielectric substrate (3); a coaxial line (5) serves as a power supply structure, and the inner conductors of the two coaxial lines (5) pass through the circular hole (401) on the metal ground layer (4) and the lower dielectric substrate (3) and the upper dielectric substrate (2), and are connected to two rectangular metal patches (101) respectively, with the power supply points located on the vertical axis of symmetry of the rectangular metal patches (101).

2. The slot-based self-decoupling patch antenna according to claim 1, characterized in that, The length of the rectangular groove (102) is between 0.14λ0 and 0.15λ0, and the width is between 0.05λ0 and 0.06λ0, where λ0 is the free space wavelength corresponding to the center frequency.

3. The slot-based self-decoupling patch antenna according to claim 2, characterized in that, The length of the rectangular metal patch (101) is between 0.39λ0 and 0.40λ0, and the width is between 0.37λ0 and 0.38λ0.

4. The slot-based self-decoupling patch antenna according to claim 3, characterized in that, The thickness of the air layer is between 0.07λ0 and 0.08λ0.

5. The slot-based self-decoupling patch antenna according to any one of claims 1-4, characterized in that, Two rectangular metal patches (101) are respectively connected to the upper dielectric substrate (2), the lower dielectric substrate (3) and the metal ground layer (4) to form two patch antenna units. The rectangular slot (102) of the excitation patch antenna unit is used to change the current distribution to construct the oblique current of the coupled patch antenna unit. Combined with the expansion effect of the rectangular slot (102) of the coupled patch antenna unit on the weak electric field region, the self-decoupling of the patch antenna is realized.

6. The slot-based self-decoupling patch antenna according to claim 5, characterized in that, By adjusting the width of the rectangular slot (102), the frequency of the matching and mutual coupling zeros is changed simultaneously, and the matching is obtained by adjusting the position of the feed point along the vertical axis of symmetry, so that the expanded weak electric field region on the coupled patch antenna unit can cover the position of the feed point.

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