Dual-polarized dielectric patch antenna array suitable for being closely arranged at intervals

Abstract

The invention relates to a dual-polarized dielectric patch antenna array suitable for being closely arranged at intervals, which comprises a lower dielectric substrate, a metal reflection floor, an upper dielectric substrate and two dielectric patches arranged in an array, which are sequentially stacked from bottom to top, and is characterized in that a metal sheet is attached to the vertical surface of each dielectric patch in the Y-axis direction; capacitive coupling generated by the metal sheets is used for counteracting strong inductive coupling of two working modes of the adjacent dielectric patches, so that the isolation degree between the first port and the third port is improved, and H-surface decoupling is realized; and the attenuation constant of the TM011 mode of the antenna in an IV region is maximized by adjusting parameters, E-plane decoupling is realized, and the IV region is a region of the dielectric patch on one side of the forward direction of the Y axis. On the basis that a section and a complex decoupling structure do not need to be added, an ideal isolation effect and a distortionless radiation mode can be achieved, and coupling of the E face and the H face is restrained at the same time.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, and specifically relates to a dual-polarized dielectric patch antenna array suitable for closely spaced arrangements. Background Technology

[0002] With the rapid development of wireless communication technology, Multiple-Input Multiple-Output (MIMO) technology plays a crucial role in communication systems. Dual polarization, as an implementation method of MIMO communication systems, enables the parallel transmission of two independent signals. However, when multiple dual-polarized antenna arrays are arranged, severe coupling problems arise. Specifically, E-plane coupling and H-plane coupling lead to pattern distortion and reduced port isolation. Therefore, decoupling techniques are needed to improve the performance of closely spaced dual-polarized dielectric patch antenna arrays.

[0003] In recent years, numerous decoupling structures for dual-polarized antennas have emerged, mainly falling into two categories. One category involves loading a dielectric substrate above the antenna to achieve decoupling. Min Li's Parasitic Decoupling Technology (PDT) belongs to this category. It generates interference opposite to the original antenna coupling by deploying a parasitic decoupling structure (PDS) above the antenna array, containing parasitic scatterers, transmission lines, and reactive loads, thus suppressing mutual coupling. Xilian Chen et al. also proposed using a gradient relative permittivity (GRP) metasurface loaded above a dual-polarized slot antenna array, achieving decoupling by controlling the coupling phase between space waves and surface waves. Chu Qingxin proposed a double-layer metasurface structure, utilizing the synergistic effect of two dielectric substrates to optimize the suppression of coupling between different polarizations and propagation paths, addressing the limitations of single-layer metasurfaces while maintaining low profile characteristics. However, this type of scheme has significant structural drawbacks: loading the dielectric substrate directly increases the antenna's profile height, resulting in a taller overall structure compared to the original unloaded structure, which is detrimental to the miniaturization and low-profile design requirements of the device. Another approach involves adding decoupling structures between antennas to cancel coupling paths. Yi-Ming Zhang et al. constructed a ring network containing 12 transmission lines with different characteristic impedances and electrical lengths between the antenna elements of a 2×2 dual-polarized patch antenna array, canceling common-polarization coupling in the vertical, horizontal, and diagonal directions, respectively. Shuai Zhang et al. proposed a decoupling grounding (DG) technique, which adjusts the shape and height of the small ground plane below each antenna element to make the free-space coupling and the current coupling on the ground plane out of phase and cancel each other out. This approach does not require additional lateral space between antenna elements and is suitable for large-scale single-polarized and dual-polarized arrays. Chen Fuchang et al. proposed a hybrid decoupling scheme based on artificial magnetic conductors (AMC) and array antenna decoupling surfaces (ADS). The AMC is used to suppress E-plane coupling and reduce the profile, while the ADS is combined to simultaneously suppress E-plane and H-plane coupling. However, such solutions require large spacing between antennas, and the decoupling structure often includes complex transmission line networks, phase compensation elements, or periodic metal patch arrays, which significantly increases the overall structural complexity of the antenna, leading to unavoidable increased losses and affecting the antenna's radiation efficiency.

[0004] Dielectric patch antennas (DPAs), as a type of quasi-planar directional radiating antenna (DRA), not only possess the advantages of DRAs such as multimode characteristics and design freedom, but also inherit the characteristics of traditional multipole patch antennas (MPA). Therefore, DPAs can be regarded as a compromise between traditional DRAs and MPAs, and have significant application potential in modern communication systems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and propose a dual-polarized dielectric patch antenna array suitable for closely spaced arrays. Without increasing the profile and complex decoupling structure, it can achieve ideal isolation effect and distortion-free radiation mode, while suppressing E-plane and H-plane coupling.

[0006] To achieve the objective of this invention, the present invention provides a dual-polarized dielectric patch antenna array suitable for closely spaced arrays, comprising a lower dielectric substrate, a metal reflector ground plane, an upper dielectric substrate, and two dielectric patches arranged in an array, stacked sequentially from bottom to top. The lower surface of the lower dielectric substrate is provided with a first dual-polarized feed network and a second dual-polarized feed network that couple and feed the two dielectric patches through a first coupling slot and a second coupling slot on the metal reflector ground plane, respectively. The first dual-polarized feed network connects a first port in the X-axis direction and a second port in the Y-axis direction, respectively. The second dual-polarized feed network connects a third port in the X-axis direction and a fourth port in the Y-axis direction, respectively. The invention is characterized in that a metal sheet is attached to the vertical surface of the dielectric patch in the Y-axis direction. The capacitive coupling generated by the metal sheet cancels the strong inductive coupling between the two operating modes of adjacent dielectric patches, thereby improving the isolation between the first port and the third port and achieving H-plane decoupling. The two operating modes are... mode and inversion Mode; by adjusting parameters to make the antenna's TM 011 Mode decay constant in region IV To maximize and achieve E-plane decoupling, the IV region is the area of ​​the dielectric patch on the positive Y-axis side, wherein the parameters include: the dielectric constant of the upper dielectric substrate. The dielectric constant of the dielectric patch The height of the dielectric patch Height of the upper dielectric substrate .

[0007] Furthermore, both the first and second dual-polarization feed networks include two orthogonal 50-ohm transmission lines and Y-shaped feed lines connected to the corresponding 50-ohm transmission lines. One of the Y-shaped feed lines is broken at the intersection and connected by a metal bridge disposed on the upper surface of the lower dielectric substrate and insulated from the metal reflective ground plane.

[0008] Furthermore, by setting a larger and and control the smaller and , making antenna TM 011 Mode decay constant in region IV To maximize.

[0009] Furthermore, the coupling coefficient between adjacent dielectric patch antenna elements S represents the center-to-center spacing of the dielectric patch antenna elements. The reference coupling coefficient is denoted as .

[0010] The present invention proposes a dual-polarized dielectric patch antenna array suitable for closely spaced arrays. By placing a metal strip on the Y-axis side of the dielectric patch, capacitive coupling is used to cancel inductive coupling, achieving H-plane decoupling. The antenna's TM is adjusted by modifying parameters. 011 Mode decay constant in region IV By maximizing the decoupling of the E-plane, this invention achieves ideal isolation and distortion-free radiation modes without adding cross-sections or complex decoupling structures, while simultaneously suppressing E-plane and H-plane coupling. Attached Figure Description

[0011] The invention will now be further described with reference to the accompanying drawings;

[0012] Figure 1 This is an exploded 3D structural diagram of the dual-polarized dielectric patch antenna array according to an embodiment of the present invention.

[0013] Figure 2 This is a schematic diagram of the metal reflector ground plane of the dual-polarized dielectric patch antenna array according to an embodiment of the present invention.

[0014] Figure 3 This is a schematic diagram of the feeding network of the dual-polarized dielectric patch antenna array in this embodiment.

[0015] Figure 4 This is an equivalent circuit model diagram of the dual-polarized dielectric patch antenna array in this embodiment; (a) without metal strip, (b) with metal strip.

[0016] Figure 5 This is the simulation result of the isolation between port S1 and port S3 of the dual-polarized dielectric patch antenna array in this embodiment.

[0017] Figure 6 It is a dielectric patch antenna operating in TM 011 Electric and magnetic field analysis diagrams under the model; (a) side view, (b) top view.

[0018] Figure 7 This is the simulation result of the isolation between port S2 and port S4 of the dual-polarized dielectric patch antenna array in this embodiment.

[0019] Figure 8 These are the performance radiation patterns of the dual-polarized dielectric patch antenna array in this embodiment; (a) radiation pattern under port S2 excitation, (b) radiation pattern under port S1 excitation. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] The embodiments of the present invention are applicable to closely spaced dual-polarized dielectric patch antenna arrays, the three-dimensional structure of which is as follows: Figure 1 As shown, in order to illustrate in detail Figure 2 , Figure 3 The diagram shows the metal reflective floor and the power supply network.

[0022] The detailed parameters of the antenna in this embodiment are as follows:

[0023] , , , , , , , , ,

[0024] , , , ,

[0025] , , , , , , , , ,

[0026] , , , , ,

[0027] , , .

[0028] This embodiment applies to a closely spaced dual-polarized dielectric patch antenna array, comprising a lower dielectric substrate 1, a metal reflector ground plane 2, an upper dielectric substrate 3, and two dielectric patches 4 arranged in the array, stacked sequentially from bottom to top. The lower surface of the lower dielectric substrate 1 has a first dual-polarized feed network 7 and a second dual-polarized feed network 8 that couple and feed the two dielectric patches 4 through a first coupling slot 5 and a second coupling slot 6 on the metal reflector ground plane 2, respectively. The first dual-polarized feed network 7 is connected to a first port S1 in the X-axis direction and a second port S2 in the Y-axis direction, respectively. The second dual-polarized feed network 7 is connected to a third port S3 in the X-axis direction and a fourth port S4 in the Y-axis direction, respectively. The antenna has two operating modes, namely... mode and inversion mold.

[0029] like Figure 2 , Figure 3 As shown, both the first coupling slot 5 and the second coupling slot 6 are cross-shaped coupling slots. The first dual-polarization feed network 7 and the second dual-polarization feed network 8 each include two orthogonal 50-ohm transmission lines 12 and Y-shaped feed lines 13 connected to the corresponding 50-ohm transmission lines. One branch of the Y-shaped feed line 13 is broken at the intersection and connected via a metal bridge 9 disposed on the upper surface of the lower dielectric substrate 1 and insulated from the metal reflector 2. Specifically, the metal reflector 2 has an insulating groove 11, and the metal bridge 9 is disposed inside the insulating groove 11 and insulated from it. Both ends of the metal bridge 9 are connected to the broken section of the Y-shaped feed line 13 through metallized through-holes 10 penetrating the lower dielectric substrate 1. To adjust impedance matching, the end of the Y-shaped feed line 13 in the antenna feed network of this embodiment has a bent stub. In the orthogonal feed network of a dual-polarized dielectric patch antenna array, a bridging structure is used to enable the crossing of microstrip feed lines, preventing physical contact and electrical short circuits between feed lines with different polarization directions on the same metal layer, ensuring independent transmission of signals at the four ports without interference. This structure only serves to isolate the traces and maintain impedance continuity; it does not change the antenna's radiation mode or decoupling mechanism. It can maintain stable port impedance matching and reduce transmission loss in a compact layout without increasing the antenna profile height or structural complexity.

[0030] Figure 1 , Figure 2 , Figure 3 This demonstrates the structure of a closely spaced dual-polarized dielectric patch antenna array, consisting of two square dielectric patches DP (side length...). ,high , , The volume of ) is The upper dielectric substrate 3 is a Rogers RO3003 laminate ( , The lower dielectric substrate 1 is a Rogers RO4003 laminate ( , Their heights are respectively and Substrate 1 and the square DP form a DP resonator. The feed network is arranged on the bottom layer of the lower dielectric substrate 1. Detailed parameter values ​​are listed below. Figure 1 , Figure 2 and Figure 3 As shown in the figure caption, a metal sheet 9 is attached to the vertical surface of the dielectric patch 4 in the Y-axis direction. The capacitive coupling generated by the metal sheet 9 is used to cancel the strong inductive coupling between the two working modes of the adjacent dielectric patches 4, thereby improving the isolation between the first port S1 and the third port S3 and realizing H-plane decoupling.

[0031] To elaborate on the decoupling process of the dual-polarized dielectric patch antenna array, the isolation improvement of the four ports is decomposed into two sets of orthogonal polarization port isolation optimization processes: the first port S1 and the third port S3, and the second port S2 and the fourth port S4. These processes are based on the self-decoupling principle of mode attenuation constant and the neutralization principle of inductive-capacitive coupling, respectively, ultimately achieving simultaneous suppression of coupling between the E-plane and the H-plane.

[0032] The improved isolation of S13 is achieved by attaching metal strips (14mm long and 3.3mm high) along the y-axis on both sides of the two DPs. The capacitive coupling of these two pairs of metal strips can cancel the inductive effect generated by the metal strips and the strong inductive coupling of the two TM modes, thereby achieving broadband isolation and H-plane decoupling.

[0033] The first port S1 and the third port S3 correspond to another orthogonal polarization direction, and their coupling is mainly H-plane inductive coupling, and the dual-polarization DPA operates in this mode. Mode and Inversion Strong inductive coupling exists at the non-radiative edges of the model. To achieve broadband decoupling, an isolation enhancement process is required:

[0034] To counteract this coupling, this design attaches two opposite metal strips along the y-axis to both sides of the two dielectric patches DP. These metal strips introduce capacitive coupling, neutralizing the inductive-capacitive coupling. Here, a capacitance Cs is generated by loading the metal strips, achieving a balance between inductive and capacitive coupling, thus allowing for simultaneous decoupling of both modes.

[0035] Equivalent circuit such as Figure 4 As shown, based on the equivalent circuit model analysis, without the metal strip, the two DPA units... Mode and Inversion The modules are respectively composed of , , and , , Equivalent modeling, power supply structure adopts The capacitor circuit simulates slot-coupled feeding, and the inductive coupling coefficient M represents the coupling between two units. In this case, strong inductive coupling leads to poor isolation. ).

[0036] After the metal strip is loaded, the metal strip is equivalent to a capacitor. Its value can be approximated by the parallel plate capacitance model:

[0037]

[0038] in, The vacuum permittivity, The length of the metal strip. The height of the metal strip. The spacing between the metal strips. The condition for neutralization of inductive-capacitive coupling is:

[0039]

[0040] Right now:

[0041]

[0042] Optimization was achieved by adjusting the length (14mm) and height (3.3mm) of metal strip 9. Numerical value, making This condition is met, thus offsetting inductive coupling, while the additional inductive effect introduced by the metal strip is also neutralized by capacitive coupling, achieving broadband decoupling.

[0043] like Figure 5 Simulation results show that after loading the metal strip, the isolation between port 1 and port 3 ( The impedance matching performance is improved to over -20dB in the 4.37-4.55GHz band, and remains stable in the 4.45-4.55GHz band. This achieves effective decoupling over a wide bandwidth.

[0044] In this embodiment, the isolation S24 between the second port S2 and the fourth port S4 is improved by reasonably selecting physical parameters and controlling the mode attenuation constant to achieve E-plane decoupling.

[0045] The study found that the second port 2 and the fourth port 4 correspond to the same polarization direction, and their coupling mainly originates from E-plane electromagnetic coupling. This coupling is caused by external electromagnetic coupling of the DPR (dielectric patch resonator). Mode attenuation field dominates. According to open waveguide theory, DPR is dominated by DP (high dielectric constant). ) and substrate 1 with low dielectric constant It is formed by fusion. The mode forms an attenuation field outside the DPR, and the attenuation characteristic along the y-axis direction is determined by the attenuation constant Determine.

[0046] From Figure 6 It can be seen that the surrounding of the dielectric patch antenna (DPR) is divided into seven regions. Here, a detailed analysis is mainly carried out on the DPR and its top and side regions I-IV, and regions VI and VII are ignored.

[0047] In region I, that is, in the DP (|z|≤h1 / 2), the field inside it is a standing wave field, and the function along the z-axis direction can be described in the form of a trigonometric function.

[0048]

[0049] In region II, that is, in the air (z>h1 / 2), its electric field is an attenuation field, which dissipates at infinity along the z-axis direction and gradually approaches zero. Therefore, the function along the z-axis direction can be expressed in the form of an exponential function.

[0050]

[0051] In region III, that is, in the upper dielectric substrate (-h1 / 2-h2<z<-h1 / 2), its electric field is also an attenuation field. However, it should be noted that different from region II, there is a metal ground (equivalent to an electric wall) at the bottom of region III. Therefore, the function of this region along the z-axis direction can be expressed with the help of hyperbolic functions.

[0052]

[0053] In region IV, that is, in the air (|y|>a / 2), its attenuated electric field can be expressed as

[0054]

[0055] In region V, in the air (|x|>a / 2), it is also an attenuation field, and its electric field is

[0056]

[0057] Among them, k x 、k y 、k z respectively represent the wave numbers along the x, y, and z axes. α1, α2, α3, and α4 respectively represent the attenuation constants of the TM 011 mode in regions II, III, IV, and V; represents the permittivity in vacuum, represents the amplitude coefficient.

[0058] The DPR can be equivalent to a layered dielectric waveguide. The field distribution of the mode satisfies the Helmholtz equation, and the coupling coefficient K between adjacent DPA elements can be expressed as: Where S is the center-to-center distance of the elements. The reference coupling coefficient is not a universal constant; it is a reference coupling coefficient uniquely determined by the specific physical structure, operating frequency, and boundary conditions. Its physical meaning is: when the center-to-center spacing S of the coupled elements approaches 0 (or a certain reference spacing S0 is taken), the limiting value of the coupling coefficient between the two elements is divided by the reference value. In this embodiment, the center-to-center spacing of the elements... .

[0059] Therefore, a feasible approach is to adjust the parameters to make the attenuation constant... The larger the value, the smaller the coupling coefficient K, and the more significant the coupling suppression effect. To increase... This design achieves its effect by optimizing the ratio of structural parameters: selecting a larger ratio... (69 / 3=23) and (69 / 0.93≈74.19), while controlling the smaller (3 / 0.93≈3.23) and (3 / 1.524≈1.97). Analysis shows that this type of parameter combination can make... Significantly increased, thereby strengthening The dissipation rate of the mode decay field.

[0060] In this embodiment, the antenna's TM is adjusted by modifying parameters. 011 Mode decay constant in region IV To maximize the E-plane decoupling, the parameters to be adjusted include the dielectric constant of the upper dielectric substrate 3. The dielectric constant of dielectric patch 4 The height of dielectric patch 4 The height of the upper dielectric substrate 3 By setting a larger and and control the smaller and , making antenna TM 011 Mode decay constant in region IV To maximize.

[0061] Parameter adjustment target: Greater than 18 Greater than 40 Less than 3.9 Less than 2.3. And the attenuation constant... An ideal value greater than 800 can achieve ideal isolation and distortion-free radiation modes, while suppressing coupling between the E and H planes. It should be noted that... and The larger the value, the better the isolation, but the narrower the bandwidth. Correspondingly, and A lower isolation level results in better isolation, but this also leads to narrower bandwidth. Therefore, when adjusting parameters, it is necessary to balance isolation with operating bandwidth. It is recommended to maximize isolation while meeting bandwidth requirements.

[0062] like Figure 7 Simulation results show that, through the above parameter optimization, the isolation between the second port S2 and the fourth port S4 is improved. Even after optimization, it remains around -20dB, maintaining a stable low coupling level in the 4.39-4.68 GHz frequency band. This verifies the effectiveness of the self-decoupling principle of mode decay constant.

[0063] The performance radiation pattern of the dual-polarized dielectric patch antenna array in this embodiment is shown in the figure. Figure 8 .from Figure 8 As shown in (a), when port S2 is excited, the antenna array exhibits no distortion in its radiation pattern within the operating frequency band, with the main radiation direction pointing towards the zenith. The sidelobe level is controlled below -10dB, and the E-plane coupling is effectively suppressed after self-decoupling via the mode attenuation constant, resulting in stable radiation characteristics. Figure 8 As can be seen in (b), when port S1 is excited, the antenna array achieves orthogonal polarization radiation with good pattern symmetry. The inductive coupling of the H-plane is significantly reduced after being neutralized by the metal strip capacitively, the port isolation is improved, and the radiation performance meets the standard.

[0064] In addition to the embodiments described above, the present invention may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A dual-polarized dielectric patch antenna array suitable for closely spaced arrangement, comprising a lower dielectric substrate (1), a metal reflector ground plane (2), an upper dielectric substrate (3), and two dielectric patches (4) arranged in an array, stacked sequentially from bottom to top. The lower surface of the lower dielectric substrate (1) is provided with a first dual-polarized feed network (7) and a second dual-polarized feed network (8) that couple and feed the two dielectric patches (4) through a first coupling slot (5) and a second coupling slot (6) on the metal reflector ground plane (2), respectively. The first dual-polarized feed network (7) is connected to a first port (S1) in the X-axis direction and a second port (S2) in the Y-axis direction, respectively. The second dual-polarized feed network (7) is connected to a third port (S3) in the X-axis direction and a fourth port (S4) in the Y-axis direction, respectively. A metal sheet (9) is attached to the vertical surface of the dielectric patch (4) in the Y-axis direction. The capacitive coupling generated by the metal sheet (9) is used to cancel the strong inductive coupling between the two working modes of the adjacent dielectric patches (4), thereby improving the isolation between the first port (S1) and the third port (S3) and realizing H-plane decoupling. The two working modes are: mode and inversion Mode; by adjusting parameters to make the antenna's TM 011 Mode decay constant in region IV To maximize the decoupling of the E-plane, the IV region is the area of ​​the dielectric patch (4) on the positive Y-axis side, wherein the parameters include: the dielectric constant of the upper dielectric substrate (3). The dielectric constant of the dielectric patch (4) The height of the dielectric patch (4) The height of the upper dielectric substrate (3) .

2. The dual-polarized dielectric patch antenna array suitable for closely spaced arrangements according to claim 1, characterized in that: Both the first coupling gap (5) and the second coupling gap (6) are cross-shaped coupling grooves.

3. The dual-polarized dielectric patch antenna array suitable for closely spaced arrangements according to claim 1, characterized in that: The first dual-polarization feed network (7) and the second dual-polarization feed network (8) both include two orthogonal 50-ohm transmission lines (12) and Y-type feed lines (13) connected to the corresponding 50-ohm transmission lines. One of the Y-type feed lines (13) is broken at the intersection and connected by a metal bridge (9) disposed on the upper surface of the lower dielectric substrate (1) and insulated from the metal reflective floor (2).

4. The dual-polarized dielectric patch antenna array suitable for closely spaced arrangements according to claim 3, characterized in that: The two ends of the metal bridge (9) are connected to the break point of the Y-type feed line (13) through the metallized through-hole (10) penetrating the lower dielectric substrate (1).

5. The dual-polarized dielectric patch antenna array suitable for closely spaced arrangements according to claim 3, characterized in that: The metal reflective floor (2) has an insulating groove (11), and the metal bridge (9) is disposed inside the insulating groove (11) and is insulated from the insulating groove (11).

6. The dual-polarized dielectric patch antenna array suitable for closely spaced arrangements according to claim 1, characterized in that: The Y-type feeder (13) has a bent branch at its end for adjusting impedance matching.

7. The dual-polarized dielectric patch antenna array suitable for closely spaced arrangements according to claim 1, characterized in that: By setting a larger and and control the smaller and , making antenna TM 011 Mode decay constant in region IV To maximize.

8. The dual-polarized dielectric patch antenna array suitable for closely spaced arrangements according to claim 1, characterized in that: Coupling coefficient between adjacent dielectric patch antenna elements S represents the center-to-center spacing of the dielectric patch antenna elements. The reference coupling coefficient is denoted as .

9. The dual-polarized dielectric patch antenna array suitable for closely spaced arrangements according to claim 1, characterized in that: Parameter adjustment target: Greater than 18 Greater than 40 Less than 3.9 Less than 2.

3.

10. The dual-polarized dielectric patch antenna array suitable for closely spaced arrangements according to claim 1, characterized in that: Attenuation constant The ideal value is greater than 800.

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