A four-element dual-polarized double-layer branched microstrip antenna array

Abstract

The present invention discloses a four-element dual-polarization double-layer branched microstrip antenna array, which belongs to the field of navigation technology. The antenna array comprises a four-element capacitive reactance matching embedded patch, a four-element dual-polarization patch, a microstrip branch excitation plate, a dual-polarization coaxial feeding excitation column, a bottom metal ground plate, a microstrip line feeding excitation plate and a polarization port; the bottom metal ground plate is arranged at the bottom of a second substrate, the polarization ports are provided in four groups, two in each group, and the four groups of polarization ports are respectively close to the four corners of the second substrate; the bottom metal ground plate is provided with through holes corresponding to the positions of the polarization ports, the bottoms of the polarization ports are arranged in the through holes, and the tops are provided with dual-polarization coaxial feeding excitation columns extending to the top of the first substrate; the tops of the dual-polarization coaxial feeding excitation columns are provided with a microstrip line feeding excitation plate, two adjacent microstrip line feeding excitation plates are commonly connected to a four-element dual-polarization patch, and a microstrip branch excitation plate is further provided at the connection between the microstrip line feeding excitation plate and the four-element dual-polarization patch.

Description

Technical Field

[0001] The invention discloses a four-element dual-polarization double-layer branched microstrip antenna array, belonging to the field of navigation technology. Background Art

[0002] "Low-coupling, miniaturized sensor antenna arrays" have long been a hot topic and a challenge in antenna research. Antennas are crucial components in mobile devices (WLAN, mobile phones, Bluetooth devices, laptops, etc.), performing energy conversion and directional electromagnetic radiation. With the rise of the Internet of Things, the increasing number of GPS navigation wireless base station electronic products using the 1.575 GHz frequency band has placed higher demands on antennas with miniaturization and interference resistance.

[0003] Microstrip antennas, due to their small size, light weight, simple manufacturing process, and conformal conformality with PCB boards, easily transmit or receive transmitted data and information, improving the reliability of wireless transmission. Without mechanical structures or other connecting devices, microstrip antennas can be equivalent to a resonant cavity, offering high value within the resonant frequency band. Existing wireless mobile terminal devices typically utilize multiple RF antennas. However, key specifications (such as antenna size, bandwidth, and gain) are constrained by physical principles such as gain and bandwidth limits at fixed dimensions. This makes miniaturization of RF antennas increasingly difficult. Furthermore, the complexity of RF electromagnetic field distribution, approaching physical limits, presents significant technical challenges. Furthermore, when the spacing between the two miniaturized elements is less than half a wavelength, coupling interference is highly likely to occur, distorting the antenna pattern and degrading antenna performance. Therefore, designing an antenna with low coupling and high isolation without changing the antenna size has become a pressing issue.

[0004] CN202010845032.7 discloses a concentric semicircular microstrip antenna. The structure of the monopole unit is relatively simple and meets the requirements of 1.575GHz GPS sensors. CN202797265U discloses a single circular small microstrip antenna. The present invention adopts a circular branch patch antenna design, which will greatly increase the antenna array gain through a multi-element antenna design.

[0005] The existing technology faces a problem: most mobile wireless communication devices use multiple RF antennas in an array. However, some key performance indicators of these arrays (such as antenna size, bandwidth, and gain) are limited by fundamental physical principles (such as gain and bandwidth limits for a fixed size). Furthermore, a traditional N-element RF antenna array only provides N times the degrees of freedom for controlling the array beam, severely limited by the number of elements in the array. This necessitates increasing the number of elements in the design of traditional antenna arrays. Summary of the Invention

[0006] The invention discloses a four-element dual-polarized double-layer branched microstrip antenna array to solve the problems of increased resonance loss and high cost of smart antenna arrays in the prior art.

[0007] A four-element dual-polarized double-layer branched microstrip antenna array comprises a first substrate and a second substrate, wherein the first substrate is arranged on top of the second substrate, and further comprises a four-element capacitive reactance matching embedded patch, a four-element dual-polarization patch, a microstrip branch excitation patch, a dual-polarization coaxial feed excitation column, a bottom metal ground plate, a microstrip line feed excitation patch, and a polarization port;

[0008] The bottom metal ground plate is provided at the bottom of the second substrate. The polarization ports are provided in four groups, with two in each group. The four groups of polarization ports are respectively located near the four corners of the second substrate. The bottom metal ground plate is provided with through holes corresponding to the positions of the polarization ports. The bottoms of the polarization ports are provided in the through holes, and the tops are provided with dual-polarization coaxial feeding excitation columns extending to the top of the first substrate.

[0009] A microstrip line feeding excitation plate is provided on the top of the dual-polarization coaxial feeding excitation column. Two adjacent microstrip line feeding excitation plates are connected to a four-element dual-polarization patch. A microstrip branch excitation plate is also provided at the connection between the microstrip line feeding excitation plate and the four-element dual-polarization patch.

[0010] Preferably, the four-element dual-polarization patch includes a four-element circular patch and two orthogonal rectangular patches, one end of the orthogonal rectangular patch is connected to the four-element circular patch, and the other end is connected to the microstrip line feeding excitation patch, and the microstrip branch excitation patch is vertically connected to the orthogonal rectangular patch.

[0011] Preferably, two orthogonal rectangular patches connecting the same four-element circular patch are perpendicular to each other.

[0012] Preferably, the corners of the microstrip branch excitation piece and the four-element dual-polarization patch and the adjacent second substrate are arranged on the opposite sides of the two dual-polarization coaxial feeding excitation columns.

[0013] Preferably, the radius of the monopole surface radiator of the quaternary circular patch is less than λ b / 4, the array element spacing is less than λ b / 2, where λ b is the wavelength in free space at the GPS resonant frequency of 1.575 GHz.

[0014] Preferably, the four-element capacitive reactance matching embedded patch is provided in the second substrate at a distance h / 3 from the first substrate, where h is the sum of the thicknesses of the first substrate and the second substrate.

[0015] Preferably, for a 1.575 GHz GPS band antenna, the element spacing of the four-element dual-polarization branch patch is 0.5λ. b , Among them, λ bis the free space wavelength of the LTE resonant frequency, εr is the dielectric constant of the Rogers RO3010 dielectric layer, c is the speed of light, and f is the LTE resonant frequency.

[0016] Preferably, the polarization port is circular.

[0017] The present invention has the following advantages: compared with the existing technology, the present invention has a double degree of freedom beam control function, and has the advantages of low cost, easy commonality and miniaturization, and is suitable for use in intelligent LTE wireless sensor modules; low coupling and high isolation, achieving miniaturization; the resonance point is concentrated in the 1.575GHz GPS frequency band, expanding the LTE bandwidth by 100M, the omnidirectional radiation gain reaches 8dB, and the structure based on the upper metal sheet can flexibly adjust the size of the antenna dipole unit, while ensuring that the antenna array resonator maintains clearance to achieve high relevant gain and ultra-bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural diagram of the present invention;

[0019] Figure 2 is the return loss graph;

[0020] Figure 3 is the EH surface radiation pattern;

[0021] Figure 4 is the three-dimensional directional gain map;

[0022] The reference numerals include: 1-first substrate; 2-second substrate; 3-quadruple capacitive matching embedded patch; 4-quadruple dual-polarization patch; 5-microstrip branch excitation plate; 6-vertical feeding excitation column; 7-horizontal feeding excitation column; 8-metal ground plate; 9-microstrip line feeding excitation plate; 10-polarization port. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0024] A four-element dual-polarized double-layer branched microstrip antenna array, comprising a first substrate 1 and a second substrate 2, wherein the first substrate 1 is arranged on top of the second substrate 2, and further comprising a four-element capacitive reactance matching embedded patch 3, a four-element dual-polarization patch 4, a microstrip branch excitation plate 5, a dual-polarization coaxial feed excitation column, a bottom metal ground plate 8, a microstrip line feed excitation plate 9, and a polarization port 10;

[0025] The bottom metal ground plate 8 is provided at the bottom of the second substrate 2. The polarization ports 10 are provided in four groups, each with two polarization ports. The four groups of polarization ports 10 are respectively located near the four corners of the second substrate 2. The bottom metal ground plate 8 is provided with through holes corresponding to the positions of the polarization ports 10. The bottom of the polarization ports 10 is provided in the through holes, and the top is provided with a dual-polarization coaxial feeding excitation column extending to the top of the first substrate 1.

[0026] A microstrip line feeding excitation plate 9 is provided on the top of the dual-polarization coaxial feeding excitation column. Two adjacent microstrip line feeding excitation plates 9 are connected to a four-element dual-polarization patch 4. A microstrip branch excitation plate 5 is also provided at the connection between the microstrip line feeding excitation plate 9 and the four-element dual-polarization patch 4.

[0027] The four-element dual-polarization patch 4 includes a four-element circular patch and two orthogonal rectangular patches. One end of the orthogonal rectangular patch is connected to the four-element circular patch, and the other end is connected to the microstrip line feeding excitation patch 9. The microstrip branch excitation patch 5 is vertically connected to the orthogonal rectangular patch.

[0028] The two orthogonal rectangular patches connecting the same quaternary circular patch are perpendicular to each other.

[0029] The microstrip branch excitation piece 5 and the quad dual-polarization patch 4 and the corners of the second substrate 2 adjacent thereto are arranged on the opposite sides of the two dual-polarization coaxial feeding excitation columns.

[0030] The radius of the monopole surface radiator of the quaternary circular patch is less than λ b / 4, the array element spacing is less than λ b / 2, where λ b is the wavelength in free space at the GPS resonant frequency of 1.575 GHz.

[0031] The quaternary capacitive reactance matching embedded patch 3 is provided in the second substrate 2 at a distance of 1h / 3 from the first substrate, where h is the sum of the thicknesses of the first substrate 1 and the second substrate 2 .

[0032] For the 1.575GHz GPS band antenna, the element spacing of the four-element dual-polarization branch patch is 0.5λ b , Among them, λ b is the free space wavelength of the LTE resonant frequency, εr is the dielectric constant of the Rogers RO3010 dielectric layer, c is the speed of light, and f is the LTE resonant frequency.

[0033] The polarization port 10 is circular.

[0034] The structure of the present invention is as follows Figure 1, which can realize the information transmission of GPS navigation base station intelligent wireless sensor antenna array in the 1.575GHz frequency band. Its composition is divided into two dielectric layers, a ground plane with depolarization port 10 and a double-layer antenna resonator. Metal radiation plates are coated on both sides of the dielectric substrate with a thickness less than half a wavelength, and a thin metal layer is coated on the bottom side as a ground plane. It is designed in combination with the PCB substrate on the relevant GPS module board. The antenna monopole is designed on a double-layer dielectric board made of Rogers RO3010(tm), and the upper and lower areas of the monopole resonator are set as clear airspace.

[0035] The microstrip line feeding excitation plate 9 is an input impedance matching transmission line, one end of which is connected to the four-element dual-polarization patch 4 and the other end is connected to one end of the dual-polarization coaxial feeding excitation column, and the other end of the dual-polarization coaxial feeding excitation column is connected to the bottom metal ground plate 8; the microstrip branch excitation plate 5 is an orthogonal rectangular patch excitation branch patch, which is used to control the antenna surface wave excitation current and achieve decoupling; the monopole profile of the four-element circular patch is low (the antenna is thin), which is conducive to conformal design to ensure excellent aerodynamic characteristics; the dual-polarization coaxial feeding excitation column includes a vertical feeding excitation column 6 and a horizontal feeding excitation column 7, which is coaxial feedback excitation between the radiating patch and the bottom metal ground plate 8, one end of which is connected to the microstrip line feeding excitation plate 9 and the other end is connected to the polarization port 10 to realize electromagnetic wave TE wave transmission between the radiating patch and the metal ground layer; the bottom metal ground plate 8 realizes electromagnetic wave loop radiation, and the eight polarization ports 10 can realize the connection between the bottom metal ground and the dual-polarization coaxial feeding excitation column based on the integral transmission line.

[0036] The four-element dual-polarization patch 4 and the four-element capacitive impedance matching embedded patch 3 generate an excitation source through a microstrip branch excitation patch 5. The impedance matching input electromagnetic wave TE wave is connected to the dual-polarization coaxial feed excitation column and transmitted to the antenna resonator. The microstrip branch excitation patch 5 is orthogonal to the microstrip transmission line, which plays a role in controlling the branch resonance. The antenna array of the present invention operates in the 1.575GHz GPS L1 frequency band. The simulated bandwidth of the antenna is 263MHz, and the relative bandwidth is 16.78%. It can be used in wireless communication devices using cellular protocol technology, NBIOt protocol technology, and LTE protocol technology.

[0037] The four-element dual-polarization patch 4 circular microstrip antenna element is the antenna radiator. It generates an excitation source through the polarization port 10 corresponding to the microstrip line feeding excitation plate 9 and the vertical feeding excitation column 6 and the other lump port (lumped port) of the horizontal feeding excitation column 7. The excitation source is transmitted to the antenna resonator through the impedance matching input feeding excitation transmission line connected to it. The current is distributed according to the standing wave, which can achieve the strongest antenna receiving capability in the horizontal direction of the feeding point. At the same time, the 1.575G frequency band of the GPS frequency band is the resonance point of the antenna array of the present invention (S11 is the minimum, and the transmission loss is the minimum point).

[0038] Based on the conventional LTE module size, the first substrate 1 with a length of 220mm and a width of 110mm and the second substrate 2 are set to have thicknesses of 5mm and 10mm respectively. The material selected is Rogers RO3010(tm), the material of the PCB board, with a dielectric constant of 10.2, which meets the design requirements of the double-layer PCB board.

[0039] The microstrip branch excitation plate 5 and the microstrip line feeding excitation plate 9 are directly connected at the edges, and are connected to the dual-polarization coaxial feeding excitation column from a section of the microstrip line feeding excitation plate 9. The length of the microstrip branch excitation plate 5 is 10 mm and the width is 5 mm. The length of the microstrip line feeding excitation plate 9 is 10 mm and the width is 3 mm. The length of the dual-polarization coaxial feeding excitation column is 15 mm and the radius is 2.5 mm.

[0040] The metal ground plate 8 is 220 mm long and 110 mm wide. To ensure clearance above and below the antenna array, the antenna array design places the metal ground plate 8 in the lower area of ​​the substrate and removes the circular port with a radius of 5 mm. This achieves clearance near the antenna and effectively reduces the impact of the grounded metal sheet on the antenna's radiation performance, allowing its polarization port 10 to generate an excitation source, indirectly enhancing the antenna's radiation efficiency and gain.

[0041] The purpose of designing the impedance-matching input transmission line microstrip line feeding excitation plate 9 is to match the impedance of the microstrip transmission line with the impedance of the dual-polarized antenna array. Its design length is required to meet the requirements of about 1 / 4 wavelength, and a polarization port 10 matching 50Ω is set at the optimized break to achieve the effect of impedance matching and reduce loss.

[0042] The capacitive reactance matching rectangular embedded patch serves as the resonant body of the antenna. Its length L has the most direct impact on the resonant frequency and input impedance of the antenna. When the length L increases, the resonant frequency of the antenna decreases, the input impedance decreases, and the antenna becomes inductive. Conversely, when the length L decreases, the resonant frequency of the antenna increases, the input impedance increases, and the antenna becomes capacitive.

[0043] The antenna device can achieve different effects by changing relevant parameters. For example, by changing the size and shape of the grounding metal plate: since the metal grounding plate has little effect on the antenna clearance requirement when meeting the antenna clearance requirement, changing the metal ground to a circular or triangular shape can meet this requirement.

[0044] Shape change of the four-element dual-polarization patch 4: This antenna is designed as a circular design; the shape can be replaced with a rectangle, diamond, etc.; the position can be replaced with a horizontal, vertical or three-dimensional structure. By determining the working frequency band to be used and adjusting the circumference of the ring radiator structure, a similar use effect can be achieved.

[0045] The performance indicators of the four-element dual-polarization double-layer branched coaxial microstrip antenna array designed by the present invention are simulated and analyzed using HFSS high-frequency simulation software. Figure 2 The return loss curve obtained is shown in Figure 2. The operating frequency bands below -10dB are 0.552GHz to 0.621GHz, 1.436GHz to 1.699GHz, and 2.802GHz to 3.505GHz, and the antenna bandwidths are 69MHz, 263MHz, and 703MHz, with relative bandwidths of 11.76%, 16.78%, and 22.29%. Figure 3 The figure shows the EH radiation pattern of the four-element dual-polarized double-layer branched coaxial microstrip antenna array at 1.575GHz. Figure 3 It can be seen that at a frequency of 1.575 GHz, the normalized radiation exhibits an "apple-shaped" omnidirectional radiation. Figure 2 In the equation, the horizontal axis is the frequency and the vertical axis is the regression loss. Figure 3 In the figure, RadiationPattern is the radiation pattern, and the vertical axis is the normalized gain (unit: dB). Figure 4 The z axis is the gain, Airbox is the air box, theta is θ, phi is dB(GainTotal) is the total gain.

[0046] Anasys Optimetrics was used in the actual simulation design to optimize and adjust antenna parameters to achieve optimal performance. Compared to similar microstrip patch antennas, the antenna's peak gain reached 6dB and its effective bandwidth reached 263MHz.

[0047] Figure 3 The radiation pattern shown is the EH plane diagram of the four-element dual-polarization double-layer branched coaxial microstrip antenna array, where the solid line is the antenna radiation curve on the E plane, and the normalized maximum gain on the E plane is 0 0 ~10 0 The dotted line is the antenna radiation curve on the H plane. The normalized maximum gain on the H plane is -15 0 ~45 0 .

[0048] The three-dimensional spatial lobe of the antenna of the present invention is as follows Figure 4 As shown, the three-dimensional directivity antenna gain is 2.98dB. Through simulation, it can be seen that the radiation intensity of the antenna along the positive direction of the Z axis is the largest, so the wireless sensor module has the best transmission and reception effects along this direction.

[0049] like Figure 4As shown, the plane angle of the antenna's top layer is the Phi-Theta plane. In the top view of the top layer, the angle phi is represented by a counterclockwise rotation around the Z-axis, which is perpendicular to the Phi-Theta plane. The Feed Point is the feed point of the printed antenna array, and the Short Point is connected to the ground terminal of the PCB circuit board, forming the short-circuit end of the antenna array. The antenna operates in the GPS 1.575GHz frequency band, and the simulated bandwidth of the antenna array is 263MHz. The simulation results meet the operating bandwidth requirements of the GPS navigation base station sensor module.

[0050] In the present invention, a four-element coupling patch embedded at h / 3 of the substrate can be equivalent to a band-stop filter, thereby reducing mutual coupling and improving isolation between antenna elements. Compared with "MIMO Antenna Mutual Coupling Reduction for WLAN Using Spiro Meander Line" published by Niraj Kumar et al., the process structure is simple, the coupling reduction effect is obvious, the antenna size is smaller, and it is easy to miniaturize and integrate with the printed circuit board. It has a significant coupling suppression effect and is suitable for wireless transceiver equipment of GPS base stations in hotspot areas, which can significantly improve the quality of information transmission.

[0051] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A four-element dual-polarization double-layer branched microstrip antenna array, comprising a first substrate and a second substrate, wherein the first substrate is arranged on top of the second substrate, characterized in that: It also includes four-element capacitive reactance matching embedded patch, four-element dual-polarization patch, microstrip branch excitation patch, dual-polarization coaxial feed excitation column, bottom metal ground plate, microstrip line feed excitation patch and polarization port; The bottom metal ground plate is provided at the bottom of the second substrate. The polarization ports are provided in four groups, with two in each group. The four groups of polarization ports are respectively located near the four corners of the second substrate. The bottom metal ground plate is provided with through holes corresponding to the positions of the polarization ports. The bottoms of the polarization ports are provided in the through holes, and the tops are provided with dual-polarization coaxial feeding excitation columns extending to the top of the first substrate. A microstrip line feeding excitation plate is provided on the top of the dual-polarization coaxial feeding excitation column. Two adjacent microstrip line feeding excitation plates are connected to a four-element dual-polarization patch. A microstrip branch excitation plate is also provided at the connection between the microstrip line feeding excitation plate and the four-element dual-polarization patch. The four-element dual-polarization patch includes a four-element circular patch and two orthogonal rectangular patches, one end of the orthogonal rectangular patch is connected to the four-element circular patch, and the other end is connected to the microstrip line feeding excitation patch, and the microstrip branch excitation patch is vertically connected to the orthogonal rectangular patch; The four-element capacitive impedance matching embedded patch is arranged in the second substrate, at a distance from the first substrate Where , is the sum of the thicknesses of the first substrate and the second substrate.

2. The four-element dual-polarization double-layer branched microstrip antenna array according to claim 1, characterized in that: The two orthogonal rectangular patches connecting the same quaternary circular patch are perpendicular to each other.

3. The four-element dual-polarization double-layer branched microstrip antenna array according to claim 2, characterized in that: The microstrip branch excitation piece, the four-element dual-polarization patch and the corners of the second substrate close to them are arranged on the opposite sides of the two dual-polarization coaxial feeding excitation columns.

4. The four-element dual-polarized double-layer branched microstrip antenna array according to claim 3, characterized in that: The radius of the monopole surface radiator of the quaternary circular patch is less than , the array element spacing is less than ,in, is the wavelength in free space at the GPS resonant frequency of 1.575 GHz, , is the dielectric constant of the Rogers RO3010 dielectric layer, is the speed of light, is the LTE resonant frequency.

5. The four-element dual-polarized double-layer branched microstrip antenna array according to claim 4, characterized in that: For the 1.575GHz GPS band antenna, the element spacing of the four-element dual-polarization patch is 0.5 .

6. The four-element dual-polarized double-layer branched microstrip antenna array according to claim 5, characterized in that: The polarization port is circular.

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