Microstrip patch antenna and method of manufacture

Abstract

The application relates to the field of antennas and provides a microstrip patch antenna and a manufacturing method, wherein the microstrip patch antenna comprises a substrate, a metal ground plate, a radiation patch, an E-shaped branch, a coaxial probe and a coaxial connector; the metal ground plate is arranged on the lower surface of the substrate; the radiation patch is arranged on the upper surface of the substrate; a groove is formed in the radiation patch, the E-shaped branch is placed in the groove, and the E-shaped branch and the radiation patch are located on the same layer; the coaxial connector is arranged on the lower surface of the substrate, the outer conductor of the coaxial connector is connected with the metal ground plate, and the inner conductor of the coaxial connector is connected with the E-shaped branch through the coaxial probe. The microstrip patch antenna provided by the application has a small feeding structure area and can realize dual polarization on a single radiation patch.

Description

Technical Field

[0001] This invention relates to the field of antennas, and in particular to a microstrip patch antenna and its manufacturing method. Background Technology

[0002] Microstrip patch antennas are commonly used antennas. To improve their bandwidth, it's often necessary to increase the antenna's thickness (profile). However, for coaxial probe feeding, increasing the antenna profile introduces series inductance, leading to impedance matching issues. To address this, Professor Guiwen Lu of City University of Hong Kong proposed using stub coupling on the lower layer of the radiating patch, introducing an additional capacitor to counteract the inductance introduced by the high-profile coaxial probe. In the sub-6GHz band, the coupling gap size between the stub and the radiating patch can fluctuate within a few tenths of a millimeter, so manual adjustment is not a problem. However, in the Ku band and above, the processing accuracy requirement is within ±0.05mm, making manual adjustment of stub coupling impractical. PCB fabrication is now necessary. In this case, the coupling gap size between the stub and the radiating patch is affected by the substrate thickness and can only be an integer multiple of 0.127mm, failing to meet the required processing accuracy.

[0003] To address this issue, some co-layer feeding schemes have been proposed. However, the drawback of co-layer feeding schemes is that the bandwidth is narrow, only 8%, and the line length is relatively long. If used in a dual-polarization scheme, the two feeding branches will interfere with each other, so it cannot be applied to dual-polarization antennas. Summary of the Invention

[0004] This application provides a microstrip patch antenna and its fabrication method to solve the problem that when coaxial probe stubs and radiating patches are fed in the same layer, the impedance bandwidth is not wide and dual polarization cannot be achieved.

[0005] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0006] According to a first aspect of the present application, a microstrip patch antenna is provided, including a substrate, a metal ground plane, a radiating patch, an E-type stub, a coaxial probe, and a coaxial connector; the metal ground plane is disposed on the lower surface of the substrate; the radiating patch is disposed on the upper surface of the substrate; the radiating patch has a groove, the E-type stub is placed in the groove, and the E-type stub and the radiating patch are located on the same layer; the coaxial connector is disposed on the lower surface of the substrate, the outer conductor of the coaxial connector is connected to the metal ground plane, and the inner conductor of the coaxial connector is connected to the E-type stub through the coaxial probe.

[0007] In one embodiment of this application, the substrate height is 0.1λ~0.25λ.

[0008] In one embodiment of this application, the coaxial probe is welded to an E-type branch.

[0009] In one embodiment of this application, the planar dimension of the radiation patch is 0.5λ. 0.5λ.

[0010] In one embodiment of this application, the coaxial connector is located directly below the E-shaped branch.

[0011] According to a second aspect of the embodiments of this application, a microstrip patch antenna is provided, comprising a substrate, a metal ground plane, a radiating patch, a first E-type stub, a second E-type stub, a first coaxial probe, a second coaxial probe, a first coaxial connector, and a second coaxial connector; the metal ground plane is disposed on the lower surface of the substrate; the radiating patch is disposed on the upper surface of the substrate; the radiating patch has a first groove and a second groove, wherein the first groove is located on one side of the center of the radiating patch, and the second groove is obtained by rotating the first groove 90° around the center of the radiating patch; the first E-type stub and the second E-type stub are respectively placed in the first groove and the second groove, the first E-type stub and the second E-type stub and the radiating patch are on the same layer, and the opening direction of both points to the center of the radiating patch; the first coaxial connector and the second coaxial connector are disposed on the lower surface of the substrate, the outer conductors of the first coaxial connector and the second coaxial connector are connected to the metal ground plane, and the inner conductors of the first coaxial connector and the second coaxial connector are respectively connected to the first E-type stub and the second E-type stub through the first coaxial probe and the second coaxial probe.

[0012] In one embodiment of this application, the substrate height is 0.1λ~0.25λ.

[0013] In one embodiment of this application, the first coaxial probe is welded to the first E-type branch, and the second coaxial probe is welded to the second E-type branch.

[0014] According to a third aspect of the embodiments of this application, a method for fabricating a microstrip patch antenna is proposed, comprising: Provide a PCB substrate; A radiating patch is fabricated on the upper surface of the PCB substrate, and a metal ground plane is fabricated on the lower surface of the PCB substrate; A groove is formed on the radiating patch, and the groove is located on one side of the center of the radiating patch; An E-shaped branch is placed in the groove, and the E-shaped branch is located in the same layer as the radiating patch; A through hole is made on the PCB substrate, penetrating the upper and lower surfaces, and the through hole is located directly below the E-shaped branch; A coaxial connector is installed at the through hole on the lower surface of the PCB substrate. The outer conductor of the coaxial connector is connected to the metal ground plane, and the inner conductor of the coaxial connector is connected to the E-type stub through the cooperation of the coaxial probe and the through hole, thus completing the fabrication of the microstrip patch antenna.

[0015] According to a second aspect of the embodiments of this application, a method for fabricating a microstrip patch antenna is proposed, comprising: Provide a PCB substrate; A radiating patch is fabricated on the upper surface of the PCB substrate, and a metal ground plane is fabricated on the lower surface of the PCB substrate; A first groove and a second groove are formed on the radiating patch. The first groove is located on one side of the center of the radiating patch, and the second groove is obtained by rotating the first groove 90° around the center of the radiating patch. A first E-shaped branch is placed in the first groove, and a second E-shaped branch is placed in the second groove. The first E-shaped branch and the second E-shaped branch are located on the same layer as the radiating patch, and their opening directions both point to the center of the radiating patch. A first through hole and a second through hole are formed on the PCB substrate, penetrating the upper and lower surfaces. The first through hole is located directly below the first E-shaped branch, and the second through hole is located directly below the second E-shaped branch. A first coaxial connector is installed at the first through hole on the lower surface of the PCB substrate. The outer conductor of the first coaxial connector is connected to the metal ground plane, and the inner conductor of the first coaxial connector is connected to the first E-type branch through the cooperation of the first coaxial probe and the first through hole. A second coaxial connector is installed at the second through hole on the lower surface of the PCB substrate. The outer conductor of the second coaxial connector is connected to the metal ground plane, and the inner conductor of the second coaxial connector is connected to the second E-type stub through the cooperation of the second coaxial probe and the second through hole, thus completing the fabrication of the microstrip patch antenna.

[0016] Compared with the prior art, the beneficial effects of adopting the above technical solution are as follows: the microstrip patch antenna feeding structure proposed in this invention has a small area and can achieve dual polarization on a single radiating patch. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0018] Figure 1 This is a schematic diagram of the microstrip patch antenna structure proposed in Embodiment 1 of this application.

[0019] Figure 2 This is a top view of the microstrip patch antenna proposed in Embodiment 1 of this application.

[0020] Figure 3 This is a schematic diagram of the microstrip patch antenna structure proposed in Embodiment 2 of this application.

[0021] Figure 4 This is a top view of the microstrip patch antenna proposed in Embodiment 2 of this application.

[0022] Figure 5 This is an equivalent circuit diagram of the antenna in the embodiments of this application.

[0023] Figure 6 This is a simulation diagram of the microstrip patch antenna S11 in Embodiment 1 of this application.

[0024] Figure 7 This is a simulation result of the Smith chart of the microstrip patch antenna in Embodiment 1 of this application.

[0025] Figure 8 This is a gain curve of the microstrip patch antenna of Embodiment 1 of this application.

[0026] Figure 9 This is a simulation diagram of the S-parameters of the microstrip patch antenna in Embodiment 2 of this application.

[0027] Figure 10 This is a simulation result of the Smith chart of the microstrip patch antenna in Embodiment 2 of this application.

[0028] Figure 11 This is a gain curve diagram of the two polarizations of the microstrip patch antenna of Embodiment 2 of this application.

[0029] Reference numerals: 1-Substrate, 2-Radiation patch, 3-Type E stub, 4-Coaxial probe, 5-Coaxial connector, 6-Metal ground plane, 701-First Type E stub, 702-First coaxial probe, 703-First coaxial connector, 801-Second Type E stub, 802-Second coaxial probe, 803-Second coaxial connector. Detailed Implementation

[0030] The embodiments of this application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar modules or modules having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Rather, the embodiments of this application include all variations, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0031] To address the issues of limited impedance bandwidth and inability to achieve dual polarization in existing co-layer feeding schemes, this application proposes a microstrip patch antenna that can achieve both single and dual polarization based on co-layer feeding.

[0032] Example 1 like Figures 1-2 As shown, this embodiment proposes a microstrip patch antenna, mainly achieving single polarization. The antenna includes a substrate 1, a metal ground plane 6, a radiating patch 2, an E-type stub 3, a coaxial probe 4, and a coaxial connector 5. Specifically, the metal ground plane 6 is disposed on the lower surface of the substrate 1; the radiating patch 2 is disposed on the upper surface of the substrate 1; the radiating patch 2 has a groove, and the E-type stub 3 is placed in the groove, with the E-type stub 3 and the radiating patch 2 located on the same layer; the coaxial connector 5 is disposed on the lower surface of the substrate 1, the outer conductor of the coaxial connector 5 is connected to the metal ground plane 6, and the inner conductor of the coaxial connector 5 is connected to the E-type stub 3 through the coaxial probe 4. The metal ground plane 6 serves as the ground layer of the microstrip patch antenna.

[0033] In one embodiment, the coaxial probe 4 is connected to the E-type stub 3 by welding. Meanwhile, the coaxial connector 5 is located directly below the E-type stub 3.

[0034] The microstrip patch antenna proposed in this embodiment can also effectively improve the antenna profile height. Specifically, in this embodiment, the planar dimension of the radiating patch 2 is 0.5λ. The substrate 1 has a height of 0.1λ to 0.25λ. It should be noted that the antenna thickness usually needs to be greater than 0.1λ to excite higher-order resonant modes. If it is too thin, it cannot excite higher-order resonant modes, and if it is too thick, it will cause severe radiation from the coaxial probe, affecting the radiation pattern.

[0035] The key to this invention lies in embedding the E-type stub 3 into the same layer as the radiating patch 2 for capacitive coupling, and increasing the cross-section. A higher cross-section means a larger series inductance L on the coaxial line (e.g., Figure 5 As shown), the E-type stub 3 used in this invention connects three branch capacitors in parallel (total capacitance C = C1 + C2 + C3), thus canceling the higher profile inductance to achieve a large bandwidth. Furthermore, the higher profile forms a higher-order resonant mode (from... Figure 7 As can be seen from the Smith chart, the S11 curve forms a small circle, which reflects the generation of two resonant modes, thus resulting in a wide impedance bandwidth.

[0036] All parameters in this invention are designed according to PCB manufacturing constraints, and can be manufactured using simple single-layer PCB processing, achieving low cost in the Ku band.

[0037] Figure 6The simulation results of S11 (S11 refers to the reflection coefficients of port 1 and port 2) of the microstrip patch antenna of this embodiment are shown. It can be seen that the single-polarized antenna of this invention has an impedance bandwidth of up to 30.3% in the -10dB range and a relatively deep depth. Figure 7 The Smith chart simulation results of the microstrip patch antenna of this embodiment are shown. It can be seen that the S11 curve forms a small circle near the 50-ohm matching point, indicating that two resonant modes are generated. Figure 8 The gain curve of the microstrip patch antenna in this embodiment is shown.

[0038] Example 2 Furthermore, the co-layer feeding scheme of this invention can achieve dual polarization and has a wider bandwidth compared to single-layer radiating patch dual-polarized antennas (traditional schemes involve coaxial probes directly contacting the radiating patch, resulting in large inductance at high profiles, poor impedance matching, and narrow bandwidth at low profiles), boasting a relative bandwidth of 26.3%. This is because the three branches of the E-type stub disperse the coupling capacitance, namely C1, C2, and C3 (total capacitance C = C1 + C2 + C3), thereby achieving the cancellation of the large inductance L of the high-profile coaxial probe with a shorter pattern (but a wider one). This allows for the arrangement of E-type probe stubs in a 90° rotation direction of the radiating patch. The specific scheme is as follows: like Figures 3-4 This embodiment proposes another microstrip patch antenna, mainly achieving dual polarization. The antenna includes a substrate 1, a metal ground plane 6, a radiating patch 2, a first E-type stub 701, a second E-type stub 801, a first coaxial probe 702, a second coaxial probe 802, a first coaxial connector 703, and a second coaxial connector 803. The metal ground plane 6 is disposed on the lower surface of the substrate 1; the radiating patch 2 is disposed on the upper surface of the substrate 1; the radiating patch 2 has a first groove and a second groove, wherein the first groove is located on one side of the center of the radiating patch 2, and the second groove is obtained by rotating the first groove 90° around the center of the radiating patch; the first E-type stub 701... The second E-shaped branch 701 is placed in the first groove and the second groove respectively. The first E-shaped branch 701, the second E-shaped branch 801 and the radiating patch 2 are on the same layer, and the opening direction of all of them points to the center of the radiating patch. The first coaxial connector 703 and the second coaxial connector 803 are disposed on the lower surface of the substrate 1. The outer conductors of the first coaxial connector 703 and the second coaxial connector 803 are connected to the metal ground plate 6. The inner conductors of the first coaxial connector 703 and the second coaxial connector 803 are connected to the first E-shaped branch 701 and the second E-shaped branch 801 respectively through the first coaxial probe 702 and the second coaxial probe 802.

[0039] Similar to a single-polarized antenna, in this embodiment, the planar dimension of the radiating patch 2 is 0.5λ. 0.5λ, the height of substrate 1 is 0.1λ~0.25λ.

[0040] In one embodiment, the first coaxial probe 702 is welded to the first E-type branch 701, and the second coaxial probe 802 is welded to the second E-type branch 801.

[0041] In practical applications, the second groove, the second E-type stub 801, the second coaxial probe 802, and the second coaxial connector 803 in the dual-polarized antenna can be obtained by copying the first groove, the first E-type stub 701, the first coaxial probe 702, and the first coaxial connector 703 and rotating them 90° along the center of the radiating patch, thus realizing the dual-polarization scheme, and the feed stub does not need to be adjusted.

[0042] In this embodiment, the first E-type stub 701, the first coaxial probe 702, and the first coaxial connector 703 are respectively a Y-polarized E-type stub, a Y-polarized coaxial probe, and a Y-polarized coaxial connector. The second E-type stub 801, the second coaxial probe 802, and the second coaxial connector 803 are respectively an X-polarized E-type stub, an X-polarized coaxial probe, and an X-polarized coaxial connector.

[0043] Because the feeding structure of the present invention has a small area, dual polarization can be achieved on a single radiating patch (traditional same-layer feeding schemes require long feed lines and cannot achieve dual polarization). Figure 9 The simulation results of the S-parameters of the microstrip patch antenna in this embodiment are shown. In the figure, S11 and S22 refer to the reflection coefficients of port 1 and port 2, and S21 refers to the transmission coefficient from port 1 to port 2. Figure 10 The Smith chart simulation results of the microstrip patch antenna of this embodiment are shown; Figure 11 The gain curves for the two polarizations of the microstrip patch antenna in this embodiment are shown. Simulation results show a -10dB bandwidth of 26.3% and a passband isolation greater than 16.5dB. The isolation is less than 20dB due to single-polarization single-end feeding; differential feeding can solve this isolation problem.

[0044] Example 3 Based on Example 1, this example proposes a method for fabricating a microstrip patch antenna as described in Example 1, including the following steps: S101, Provide a PCB substrate; S102. A radiating patch is fabricated on the upper surface of the PCB substrate, and a metal ground plane is fabricated on the lower surface of the PCB substrate; S103. A groove is formed on the radiating patch, and the groove is located on one side of the center of the radiating patch; S104. Place an E-shaped branch in the groove, wherein the E-shaped branch and the radiating patch are located in the same layer; S105. A through hole is made on the PCB substrate, penetrating the upper and lower surfaces, and the through hole is located directly below the E-shaped branch; S106. Install a coaxial connector at the through hole on the lower surface of the PCB substrate. The outer conductor of the coaxial connector is connected to the metal ground plane, and the inner conductor of the coaxial connector is connected to the E-type stub through the cooperation of the coaxial probe and the through hole, thus completing the fabrication of the microstrip patch antenna.

[0045] Example 4 Based on Example 2, this example proposes a method for fabricating a microstrip patch antenna according to Example 2, including the following steps: S201, Provide a PCB substrate; S202. A radiating patch is fabricated on the upper surface of the PCB substrate, and a metal ground plane is fabricated on the lower surface of the PCB substrate; S203. A first groove and a second groove are formed on the radiating patch. The first groove is located on one side of the center of the radiating patch, and the second groove is obtained by rotating the first groove 90° around the center of the radiating patch. S204. A first E-shaped branch is placed in the first groove, and a second E-shaped branch is placed in the second groove. The first E-shaped branch and the second E-shaped branch are located on the same layer as the radiating patch, and their opening directions both point to the center of the radiating patch. S205. A first through hole and a second through hole are formed on the PCB substrate, the first through hole being located directly below the first E-shaped branch, and the second through hole being located directly below the second E-shaped branch. S206. A first coaxial connector is installed at the first through hole on the lower surface of the PCB substrate. The outer conductor of the first coaxial connector is connected to the metal ground plane, and the inner conductor of the first coaxial connector is connected to the first E-type branch through the cooperation of the first coaxial probe and the first through hole. S207. Install a second coaxial connector at the second through hole on the lower surface of the PCB substrate. The outer conductor of the second coaxial connector is connected to the metal ground plane. The inner conductor of the second coaxial connector is connected to the second E-type stub through the cooperation of the second coaxial probe and the second through hole, thus completing the fabrication of the microstrip patch antenna.

[0046] The present invention can be well implemented through Examples 1 to 4.

[0047] It should be noted that, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances. The accompanying drawings in the embodiments are used to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0048] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A microstrip patch antenna, characterized in that, The device includes a substrate, a metal ground plane, a radiating patch, an E-shaped stub, a coaxial probe, and a coaxial connector. The metal ground plane is disposed on the lower surface of the substrate. The radiating patch is disposed on the upper surface of the substrate. The radiating patch has a groove, and the E-shaped stub is placed in the groove, with the E-shaped stub and the radiating patch located on the same layer. The coaxial connector is disposed on the lower surface of the substrate, with its outer conductor connected to the metal ground plane and its inner conductor connected to the E-shaped stub via the coaxial probe.

2. The microstrip patch antenna according to claim 1, characterized in that, The substrate height is 0.1λ~0.25λ.

3. The microstrip patch antenna according to claim 1 or 2, characterized in that, The coaxial probe is welded to the E-type branch.

4. The microstrip patch antenna according to claim 1, characterized in that, The planar dimension of the radiation patch is 0.5λ. 0.5λ.

5. The microstrip patch antenna according to claim 1, characterized in that, The coaxial connector is located directly below the E-shaped branch.

6. A microstrip patch antenna, characterized in that, The device includes a substrate, a metal ground plane, a radiating patch, a first E-shaped stub, a second E-shaped stub, a first coaxial probe, a second coaxial probe, a first coaxial connector, and a second coaxial connector. The metal ground plane is disposed on the lower surface of the substrate. The radiating patch is disposed on the upper surface of the substrate. The radiating patch has a first groove and a second groove, wherein the first groove is located on one side of the center of the radiating patch, and the second groove is obtained by rotating the first groove 90° around the center of the radiating patch. The first E-shaped stub and the second E-shaped stub are respectively placed in the first groove and the second groove, respectively. The first E-shaped stub and the second E-shaped stub are on the same layer as the radiating patch, and their opening directions all point towards the center of the radiating patch. The first coaxial connector and the second coaxial connector are disposed on the lower surface of the substrate. The outer conductors of the first coaxial connector and the second coaxial connector are connected to the metal ground plane, and the inner conductors of the first coaxial connector and the second coaxial connector are connected to the first E-shaped stub and the second E-shaped stub, respectively, through the first coaxial probe and the second coaxial probe.

7. The microstrip patch antenna according to claim 6, characterized in that, The substrate height is 0.1λ~0.25λ.

8. The microstrip patch antenna according to claim 6 or 7, characterized in that, The first coaxial probe is welded to the first E-type branch, and the second coaxial probe is welded to the second E-type branch.

9. A method for fabricating a microstrip patch antenna, characterized in that, include: Provide a PCB substrate; A radiating patch is fabricated on the upper surface of the PCB substrate, and a metal ground plane is fabricated on the lower surface of the PCB substrate; A groove is formed on the radiating patch, and the groove is located on one side of the center of the radiating patch; An E-shaped branch is placed in the groove, and the E-shaped branch is located in the same layer as the radiating patch; A through hole is made on the PCB substrate, penetrating the upper and lower surfaces, and the through hole is located directly below the E-shaped branch; A coaxial connector is installed at the through hole on the lower surface of the PCB substrate. The outer conductor of the coaxial connector is connected to the metal ground plane, and the inner conductor of the coaxial connector is connected to the E-type stub through the cooperation of the coaxial probe and the through hole, thus completing the fabrication of the microstrip patch antenna.

10. A method for fabricating a microstrip patch antenna, characterized in that, include: Provide a PCB substrate; A radiating patch is fabricated on the upper surface of the PCB substrate, and a metal ground plane is fabricated on the lower surface of the PCB substrate; A first groove and a second groove are formed on the radiating patch. The first groove is located on one side of the center of the radiating patch, and the second groove is obtained by rotating the first groove 90° around the center of the radiating patch. A first E-shaped branch is placed in the first groove, and a second E-shaped branch is placed in the second groove. The first E-shaped branch and the second E-shaped branch are located on the same layer as the radiating patch, and their opening directions both point to the center of the radiating patch. A first through hole and a second through hole are formed on the PCB substrate, penetrating the upper and lower surfaces. The first through hole is located directly below the first E-shaped branch, and the second through hole is located directly below the second E-shaped branch. A first coaxial connector is installed at the first through hole on the lower surface of the PCB substrate. The outer conductor of the first coaxial connector is connected to the metal ground plane, and the inner conductor of the first coaxial connector is connected to the first E-type branch through the cooperation of the first coaxial probe and the first through hole. A second coaxial connector is installed at the second through hole on the lower surface of the PCB substrate. The outer conductor of the second coaxial connector is connected to the metal ground plane, and the inner conductor of the second coaxial connector is connected to the second E-type stub through the cooperation of the second coaxial probe and the second through hole, thus completing the fabrication of the microstrip patch antenna.

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