Ku-band microstrip phased-array antenna unit

Abstract

The invention discloses a Ku frequency band microstrip phased-array antenna unit, the antenna unit comprises a radiation patch, a dielectric substrate and a metal grounding plate which are sequentially arranged from top to bottom, and a short circuit metal column passes through the dielectric substrate to connect the radiation patch with the metal grounding plate; the radiation patch comprises a protruding rectangular patch, an inner conductor part of the coaxial feed structure is connected with the protruding rectangular patch, and an outer conductor part of the coaxial feed structure is connected with the metal grounding plate; and the protruding rectangular patch comprises a first slit and a second slit which are symmetrically arranged. According to the invention, the impedance matching of the antenna is improved, the working bandwidth is improved, and cross polarization is greatly inhibited.

Description

Technical Field

[0001] The invention belongs to the technical field of wireless communications, and in particular relates to a Ku-band microstrip phased array antenna unit. Background Art

[0002] Microstrip phased array antennas stand out in the field of wireless communications, especially in Ku-band (12-18GHz) applications, with their outstanding characteristics, demonstrating extraordinary advantages. Their compact structure, light weight and easy manufacturing not only simplify the design and deployment process, but also greatly broaden the application scenarios. In the Ku-band, a high-frequency, strong penetrating and anti-interference field, microstrip phased array antennas completely abandon the need for traditional mechanical movement through innovative electronic scanning beam technology, achieving a revolutionary improvement in data transmission speed and a leap in system reliability.

[0003] Moreover, this type of antenna can be seamlessly integrated on complex carriers such as satellites, which not only optimizes space utilization, but also significantly enhances the overall efficiency and flexibility of the system. This highly integrated and optimized capability makes microstrip phased array antennas show unparalleled value in cutting-edge fields such as satellite communications and high-precision radar detection.

[0004] In the current microstrip antenna technology, although it has the advantages of small size, light weight, and easy integration, it still has the phenomenon of narrow bandwidth, usually between 0.7% and 7%. The narrow bandwidth characteristics limit its application in the Ku-band phased array field. At the same time, in the field of satellite communications, there are more stringent requirements on the size and weight of the antenna. Traditional microstrip antennas as phased array units may be difficult to meet the requirements of maintaining a wide bandwidth while further reducing the size of the antenna. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a Ku-band microstrip phased array antenna unit, which improves the working bandwidth and gain of the antenna and realizes the miniaturization of the antenna.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A Ku-band microstrip phased array antenna unit, the antenna unit comprising a radiation patch, a dielectric substrate and a metal ground plate arranged in sequence from top to bottom, wherein:

[0008] The short-circuit metal column passes through the dielectric substrate to connect the radiation patch to the metal ground plate;

[0009] The radiation patch includes a protruding rectangular patch, the inner conductor part of the coaxial feeding structure is connected to the protruding rectangular patch, and the outer conductor part is connected to the metal ground plate;

[0010] The protruding rectangular patch includes a first slit and a second slit that are symmetrically arranged.

[0011] Furthermore, the first slit and the second slit are symmetrically placed with respect to the feeding port of the coaxial feeding structure.

[0012] Furthermore, the short-circuit metal column is located at one end away from the protruding rectangular patch.

[0013] Furthermore, the lengths of the first slit and the second slit are the same as the length of the protruding rectangular patch along the radiation patch.

[0014] Furthermore, the radiation patch is a rectangle, and the four corners of the rectangle are obtained by removing the cut corners of the triangle.

[0015] Furthermore, the short-circuit metal column, the coaxial feeding structure, and the protruding rectangular patch are located on the symmetry axis of the radiation patch.

[0016] The beneficial effects of the present invention are:

[0017] The present invention adopts a Ku-band microstrip antenna with a single-layer structure, and realizes a low-profile design (0.08 working wavelength) through a coaxial feeding method, which greatly simplifies the structure, reduces the production cost, and provides convenience for large-scale production and application; slits are set on both sides of the radiation patch feeding, and the antenna input impedance can be adjusted by controlling the size and position of the slits, thereby significantly broadening the working bandwidth of the antenna. The antenna can work stably in a wider frequency range to meet the needs of different application scenarios; the radiation patch is short-connected to the ground plate through a metal column, which increases the equivalent inductance, not only improves the antenna bandwidth, but also suppresses cross-polarization. At the same time, the short-circuit column makes the resonant frequency shift downward, realizes the miniaturization of the antenna, and can achieve a bandwidth of 12% without additional size or parasitic units; due to its excellent performance and compact structure, the antenna of the present invention is very suitable for use as a unit of a phased array antenna array, which helps to improve the performance and reliability of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of a Ku-band microstrip phased array antenna unit of the present invention;

[0019] Figure 2 This is a schematic structural diagram of the radiation part of a Ku-band microstrip phased array antenna unit of the present invention;

[0020] Figure 3 This is a diagram showing the simulation results of the self-reflection coefficient of a Ku-band microstrip phased array antenna unit of the present invention;

[0021] Figure 4 The cross-polarization comparison diagram with and without metal pillars;

[0022] Figure 5 The far-field radiation pattern of the main plane of a Ku-band microstrip phased array antenna unit of the present invention with a phi=0° angle;

[0023] Figure 6 The far-field radiation pattern of the main plane of a Ku-band microstrip phased array antenna unit of the present invention at phi=90°;

[0024] Figure 7 A comparison chart showing the effect of adding metal pillars and narrow slits on the antenna reflection coefficient;

[0025] Figure 8 This is a schematic diagram of the overall structure of a Ku-band microstrip phased array 3×3 antenna array of the present invention;

[0026] Fig. 9 The present invention provides a Ku-band microstrip phased array antenna unit simulation scanning ±45 degrees active S parameter curve;

[0027] Fig.10 This is an S parameter curve of a Ku-band microstrip phased array 3×3 antenna array of the present invention;

[0028] Fig.11 The present invention provides a Ku-band microstrip phased array 3×3 antenna array gain curve.

[0029] Reference numerals:

[0030] 1. Radiating patch; 2. Dielectric substrate; 3. Short-circuit metal column; 4. Metal ground plate; 5. Coaxial feeding structure; 101. First slit; 102. Second slit. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0032] like Figure 1 and Figure 2As shown, the present invention provides a Ku-band microstrip phased array antenna unit, characterized in that the antenna unit adopts a single-layer structure, including a radiation patch 1, a dielectric substrate 2 and a metal ground plate 4 arranged in sequence. Among them, the short-circuit metal column 3 passes through the dielectric substrate 2 to connect the radiation patch 1 with the metal ground plate 3. The radiation patch 1 includes a protruding rectangular patch, the inner conductor part of the coaxial feeding structure 5 is connected to the protruding rectangular patch, and the outer conductor part is connected to the metal ground plate 4, and the protruding rectangular patch includes a first slit 101 and a second slit 102, and the first slit 101 and the second slit 102 are symmetrically placed about the feeding port of the coaxial feeding structure 5. The function of the short-circuit metal column 3 is to introduce equivalent inductance, change the surface current path, broaden the working frequency band, reduce the antenna size, suppress cross polarization, and thus improve the antenna gain; the first slit 101 and the second slit 102 are located on both sides of the feeding port, extending part of the surface current path, wherein the first slit 101 and the second slit 102 can be used as equivalent capacitive coupling slits, which play a role in broadening the working bandwidth and adjusting impedance matching. The antenna has a compact structure, 14% relative bandwidth, and high gain, and is suitable for forming a phased array.

[0033] In one embodiment, the dielectric substrate 2 is 10 mm long, 10 mm wide, and 1.524 mm thick. Since a single-layer structure is adopted, the thickness of the dielectric substrate 2 is the total cross-section of the antenna, which is approximately 0.08 wavelengths at the center frequency. The radiation patch 1 is located on the upper surface of the dielectric substrate 2. The radiation patch 1 is 6 mm long and 4.3 mm wide. The four corners of the radiation patch 1 are cut to facilitate fine-tuning of the resonance point and solve the frequency deviation problem. The metal ground plane 4 is located on the lower surface of the dielectric substrate 2 and is rectangular copper-clad. The length and width are consistent with the dielectric substrate 2.

[0034] In one embodiment, the radiation patch 1 is rectangular, and the rectangular patch protrudes perpendicularly along the long side of the radiation patch 1, with a width of 1.2 mm and a length of 2.5 mm. The first slit 101 and the second slit 102 are symmetrically distributed along the central axis of the protruding rectangular patch, and the distance between the two slits is 1 mm. The coaxial feeding structure 5 is located between the two slits on the protruding rectangular patch, preferably, located on the central axis of the protruding rectangular patch. The two slits are used to adjust the antenna impedance matching so that as much energy as possible is transmitted from the coaxial to the radiation patch. The length of the two slits is consistent with that of the protruding rectangular patch, and the width is 0.1 mm. The short-circuit metal column 3 is located on the radiation patch 1, preferably, at the end away from the coaxial feeding structure 5, the radiation patch 1 is connected to the metal ground plate 4 through the dielectric substrate 2, and the equivalent inductance provided by it can not only reduce the antenna resonant frequency and reduce the antenna size, but also extend the surface current path on the radiation patch, thereby widening the working bandwidth of the antenna. By combining a narrow slit at the feed point and introducing a short-circuit metal column 3, the bandwidth of the antenna is increased and the size of the antenna is reduced without deteriorating its impedance matching. The dielectric substrate 2 is made of Rogers 4350 material with a relative dielectric constant of 3.66, and the thickness of the dielectric substrate is 1.526 mm.

[0035] See also Figure 3 As shown, Figure 3 The figure shows the simulation result of the self-reflection coefficient of the Ku-band microstrip phased array antenna unit provided by the present invention. The simulation result is obtained by simulating and calculating the self-reflection coefficient of the feeding port using the commercial simulation software ANSYS HFSS_18.0. Figure 3 As shown in the figure, when the return loss is greater than 10dB, the operating frequency band covered is specifically 15.65GHz~17.65GHz, and the relative operating bandwidth is 12%. Figure 5 and Figure 6 ,like Figure 5 and Figure 6 As shown, they are the far-field radiation patterns corresponding to the horizontal plane Phi = 0 degrees and the vertical plane Phi = 90 degrees of the Ku-band microstrip antenna, and the maximum gain is 7.23dB. In order to highlight the cross-polarization suppression effect of the short-circuit metal column 3, Figure 4 The cross-polarization before and after adding the short-circuit metal column 3 is given. It can be seen that after adding the short-circuit metal column 3, the cross-polarization ratio is suppressed from -3dB to -16dB, so that more radiation can be concentrated in the main beam direction, thereby improving the antenna gain. Figure 7The effect of adding the short-circuit metal column 3 slits on the antenna reflection coefficient is given. It can be seen from the figure that without adding any structure, the antenna resonates at a high frequency, and the impedance matching of the antenna resonance point is poor and the bandwidth is narrow. By introducing the short-circuit metal column 3, the resonance point can be moved to a low frequency and the operating frequency band can be widened. By introducing two slits, the impedance matching can be adjusted and the frequency band can be widened. Combining the two structures can achieve the movement of the resonance point to a low frequency without changing the size of the antenna, and greatly improve the impedance matching. The depth of the resonance point is optimized from -15dB to -40dB, and the operating bandwidth is greatly improved.

[0036] Figure 8 The 3×3 antenna array is composed of Ku-band microstrip phased array antenna units provided by the present invention, and the spacing between the antenna units is 10 mm; Fig. 9 The Ku-band microstrip phased array antenna unit provided by the present invention has a scanning angle at 16.7 GHz, which is Fig. 9 It can be seen that the antenna can achieve Theta scanning angle from -45 degrees to 45 degrees when the reflection coefficient is <-10dB; Fig.10 The simulation results of the reflection coefficients of the 9 ports of the 3×3 antenna array composed of the Ku-band microstrip phased array antenna units provided by the present invention are as follows: Fig.10 It can be seen that each port achieves wide bandwidth below -10dB; Fig.11 The directional diagram of the 3×3 antenna array composed of the Ku-band microstrip phased array antenna units provided by the present invention shows that when the 9 units are fed with equal amplitude and in phase, the antenna beam points in the normal direction and the maximum gain value is 15.6dB.

[0037] In summary, the present invention adopts a single-layer dielectric plate structure, the antenna is compact, the feeding is simple, and it is convenient to form a phased array antenna for satellite communication in the Ku band. By cutting the corners on the radiation patch 1, it is convenient to fine-tune the resonance point and solve the frequency deviation problem. By opening slits on both sides of the coaxial feeding structure 5, the antenna impedance matching is improved and the working bandwidth is increased. By introducing the short-circuit metal column 3 to change the surface current path, the antenna size is reduced while the bandwidth is increased, and the cross polarization is greatly suppressed from -3dB to -16dB. A coaxial feeding method is adopted, the power capacity is large, the feeding impedance is easy to adjust and control, the processing is simple, and it is easy to form a wide working band. The antenna operates at 16.7GHz, which is located in the Ku band, and the -10dB impedance bandwidth is 12%.

[0038] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A Ku-band microstrip phased array antenna unit, characterized in that: The antenna unit includes a radiation patch, a dielectric substrate and a metal ground plate arranged in sequence from top to bottom, wherein: The short-circuit metal column passes through the dielectric substrate to connect the radiation patch to the metal ground plate; The radiation patch includes a protruding rectangular patch, the inner conductor part of the coaxial feeding structure is connected to the protruding rectangular patch, and the outer conductor part is connected to the metal ground plate; The protruding rectangular patch includes a first slit and a second slit that are symmetrically arranged.

2. The Ku-band microstrip phased array antenna unit according to claim 1, characterized in that: The first slit and the second slit are symmetrically placed with respect to the feeding port of the coaxial feeding structure.

3. The Ku-band microstrip phased array antenna unit according to claim 1, characterized in that: The short-circuit metal column is located at one end away from the protruding rectangular patch.

4. The Ku-band microstrip phased array antenna unit according to claim 2, characterized in that: The lengths of the first slit and the second slit are the same as the length of the protruding rectangular patch along the radiation patch.

5. The Ku-band microstrip phased array antenna unit according to claim 1, characterized in that: The radiation patch is rectangular, and the four corners of the rectangle are the cut corners of the triangle.

6. The Ku-band microstrip phased array antenna unit according to claim 1, characterized in that: The short-circuit metal column, the coaxial feeding structure, and the protruding rectangular patch are located on the symmetry axis of the radiation patch.

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