A Ku-band microstrip phased array antenna element

Abstract

The present invention discloses a Ku-band microstrip phased array antenna element. The antenna element includes a radiation patch, a dielectric substrate, and a metal ground plane that are sequentially arranged up and down. Among them, shorting metal posts pass through the dielectric substrate to connect the radiation patch to the metal ground plane; 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 plane; the protruding rectangular patch includes a first slit and a second slit that are symmetrically arranged. The present invention improves the antenna impedance matching, enhances the working bandwidth, and significantly suppresses the cross polarization.

Description

Technical Field

[0001] The present invention belongs to the field of wireless communication technology, and particularly relates to a Ku-band microstrip phased array antenna element. Background Art

[0002] Microstrip phased array antennas stand out in the field of wireless communication, especially in applications in the Ku band (12 - 18 GHz), demonstrating remarkable advantages. They have a compact structure, light weight, and are easy to manufacture. These advantages not only simplify the design and deployment process but also greatly expand the application scenarios. In the Ku band, which features high frequency, strong penetration, and excellent anti-interference performance, microstrip phased array antennas, through innovative electronically scanned beam technology, completely eliminate the need for traditional mechanical movement, achieving a revolutionary increase in data transmission speed and a leap in system reliability.

[0003] Moreover, such antennas can be seamlessly integrated onto complex carriers such as satellites, not only optimizing space utilization but also significantly enhancing 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 communication and high-precision radar detection.

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

[0005] To solve the above technical problems, the present invention provides a Ku-band microstrip phased array antenna element, which improves the operating bandwidth and gain of the antenna and realizes the miniaturization of the antenna.

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

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

[0008] Short-circuit metal posts pass through the dielectric substrate to connect the radiation patch to the metal ground plane;

[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 plane;

[0010] The protruding rectangular patch includes a first slit and a second slit which 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 post is located at one end far 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 protruding direction of the radiation patch.

[0014] Furthermore, the radiation patch is rectangular, and the four corners of the rectangle are chamfered by removing triangles.

[0015] Furthermore, the short - circuit metal post, 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 as follows:

[0017] The present invention adopts a Ku - band microstrip antenna with a single - layer structure. Through the coaxial feeding method, a low - profile design (0.08 operating wavelengths) is achieved, which greatly simplifies the structure and reduces the manufacturing cost, providing convenience for large - scale production and application. Slits are arranged on both sides of the feeding point of the radiation patch. By controlling the size and position of the slits, the input impedance of the antenna can be adjusted, thus significantly broadening the working bandwidth of the antenna. This enables the antenna to work stably in a wider frequency range and meet the requirements of different application scenarios. The radiation patch is short - circuited to the ground plane through a metal post, increasing the equivalent inductance. This not only improves the antenna bandwidth but also suppresses cross - polarization. At the same time, the short - circuit post makes the resonant frequency shift downwards, realizing the miniaturization of the antenna. A bandwidth of 12% can be achieved without additional size or parasitic elements. 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, which helps to improve the performance and reliability of the entire system. 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 It is a schematic diagram of the radiation part structure of a Ku - band microstrip phased - array antenna unit of the present invention;

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

[0021] Figure 4 It is a cross - polarization comparison diagram with and without a metal post;

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

[0023] Figure 6 This is the far - field radiation pattern of the main plane with phi = 90° for a Ku - band microstrip phased - array antenna element of the present invention;

[0024] Figure 7 This is a comparison chart of the influence of whether to add metal posts and narrow slots on the antenna reflection coefficient;

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

[0026] Figure 9 This is the simulation scan of the active S - parameter curve of ±45 degrees for a Ku - band microstrip phased - array antenna element of the present invention;

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

[0028] Figure 11 This is the gain curve of a 3×3 antenna array of a Ku - band microstrip phased - array of the present invention.

[0029] Reference numerals:

[0030] 1. Radiation patch; 2. Dielectric substrate; 3. Short - circuit metal post; 4. Metal ground plane; 5. Coaxial feeding structure; 101. First slit; 102. Second slit. Detailed implementation manners

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

[0032] Such as Figure 1 and Figure 2As shown in the figure, the present invention provides a Ku-band microstrip phased array antenna unit, which is characterized in that the antenna unit adopts a single-layer structure and includes a radiation patch 1, a dielectric substrate 2 and a metal ground plane 4 arranged in sequence from top to bottom. Among them, a short-circuit metal post 3 passes through the dielectric substrate 2 to connect the radiation patch 1 to the metal ground plane 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 plane 4. 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 with respect to the feeding port of the coaxial feeding structure 5. The function of the short-circuit metal post 3 is to introduce an equivalent inductance, change the surface current path, broaden the working frequency band while reducing the antenna size and suppressing cross polarization, thereby improving 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. Among them, the first slit 101 and the second slit 102 can be used as equivalent capacitance coupling slits, which play the role of broadening the working bandwidth and adjusting impedance matching. The antenna structure is compact, with a relative bandwidth of 14% and a relatively high gain, and is suitable for forming a phased array.

[0033] In one embodiment, the length of the dielectric substrate 2 is 10 mm, the width is 10 mm, and the thickness is 1.524 mm. 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 length of the radiation patch 1 is 6 mm and the width is 4.3 mm. Chamfers are cut at the four corners of the radiation patch 1 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 made of rectangular copper cladding, with the length and width being the same as those of the dielectric substrate 2.

[0034] In one embodiment, the radiation patch 1 is rectangular, a rectangular patch protruding in the direction perpendicular to 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, it is 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 lengths of the two slits are the same as those of the protruding rectangular patch, and the width is 0.1 mm. The short - circuit metal post 3 is located on the radiation patch 1. Preferably, at one end far from the coaxial feeding structure 5, it passes through the dielectric substrate 2 to connect the radiation patch 1 to the metal ground plane 4. The equivalent inductance provided by it can not only reduce the antenna resonance frequency, reduce the antenna size, but also extend the surface current path on the radiation patch, thereby broadening the working bandwidth of the antenna. By combining opening a narrow slit at the feeding point and introducing the short - circuit metal post 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] Please refer to Figure 3 as shown in Figure 3 which shows the simulation result diagram 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. As Figure 3 shown, when the standard is that the return loss is greater than 10 dB, the covered working frequency band is specifically 15.65 GHz to 17.65 GHz, and the relative working bandwidth is 12%. Please refer to Figure 5 and Figure 6 , as Figure 5 and Figure 6 shown, they are respectively the far - field radiation pattern diagrams corresponding to Phi = 0 degrees in the horizontal plane and Phi = 90 degrees in the vertical plane of the Ku - band microstrip antenna, and the maximum gain is 7.23 dB. In order to highlight the effect of the short - circuit metal post 3 in suppressing cross - polarization, Figure 4 the cross - polarization before adding the short - circuit metal post 3 and after adding the short - circuit metal post 3 is given. It can be seen that after adding the short - circuit metal post 3, the cross - polarization ratio is suppressed from - 3 dB to - 16 dB, so that more radiation can be concentrated in the main beam direction, improving the antenna gain. Figure 7The influence of adding short - circuit metal posts 3 and slits on the reflection coefficient of the antenna is given. It can be seen from the figure that without adding any structure, the antenna resonates at high frequencies, and the impedance matching at the resonance point of the antenna is poor, and the bandwidth is narrow. By introducing the short - circuit metal posts 3, the resonance point can be shifted to lower frequencies and the working frequency band can be broadened. By introducing two slits, the impedance matching can be adjusted and the frequency band can be broadened. Combining the two structures realizes shifting the resonance point to lower frequencies without changing the antenna size, greatly improving the impedance matching. The depth of the resonance point is optimized from - 15 dB to - 40 dB, and the working bandwidth is greatly increased.

[0036] Figure 8 This is a 3×3 antenna array composed of Ku - band microstrip phased - array antenna elements provided by the present invention. The spacing between antenna elements is 10 mm; Figure 9 This is the scanning angle of the Ku - band microstrip phased - array antenna element provided by the present invention at 16.7 GHz. From Figure 9 It can be seen that the antenna can achieve Theta scanning angle from - 45 degrees to 45 degrees when the reflection coefficient < - 10 dB; Figure 10 This is the simulation result of the reflection coefficients of the 9 ports of the 3×3 antenna array composed of Ku - band microstrip phased - array antenna elements provided by the present invention. From Figure 10 It can be seen that a wide frequency band is achieved below - 10 dB for each port; Figure 11 This is the radiation pattern of the 3×3 antenna array composed of Ku - band microstrip phased - array antenna elements provided by the present invention. It can be seen from the figure that when the 9 elements are fed with equal amplitude and in - phase, the antenna beam points in the normal direction, and the maximum gain value is 15.6 dB.

[0037] In summary, the present invention adopts a single - layer dielectric - board 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 corners on the radiation patch 1, the resonance point can be finely adjusted to solve the frequency - offset problem. By opening slits on both sides of the coaxial feeding structure 5, the impedance matching of the antenna is improved and the working bandwidth is increased. By introducing short - circuit metal posts 3, the surface - current path is changed, the bandwidth is increased while the antenna size is reduced, and the cross - polarization is greatly suppressed, from - 3 dB to - 16 dB. The coaxial feeding method is adopted, which has a large power capacity, the feeding impedance is easy to adjust and control, the processing is simple, and it is easy to form a wide working frequency band. The antenna operates at 16.7 GHz, in the Ku - band, and the - 10 dB impedance bandwidth is 12%.

[0038] In the above - described specific embodiments, the purpose, technical solution, and beneficial effects of the present invention are further described in detail. It should be understood that the above - described are only specific embodiments of the present invention and are not used to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A Ku-band microstrip phased array antenna element, characterized in that, The antenna unit includes a radiation patch, a dielectric substrate, and a metal ground plane arranged in sequence from top to bottom. Among them, a short - circuit metal post passes through the dielectric substrate to connect the radiation patch and the metal ground plane, and the short - circuit metal post is located at one end far from the feeding port; 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 plane; the protruding rectangular patch includes a first slit and a second slit symmetrically arranged; the first slit and the second slit are symmetrically placed with respect to the feeding port of the coaxial feeding structure, and the lengths of the first slit and the second slit are the same as the length of the protruding rectangular patch along the protrusion of the radiation patch, both being 2.5 mm. Among them, the width of the protruding rectangular patch is 1.2 mm, the distance between the first slit and the second slit is 1 mm, and the widths of the first slit and the second slit are both 0.1 mm.

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

3. A Ku-band microstrip phased array antenna element according to claim 1, characterized in that, the radiation patch is rectangular, and the four corners of the rectangle are chamfered by removing triangles.

4. A Ku-band microstrip phased array antenna element according to claim 1, characterized in that, the short - circuit metal post, the coaxial feeding structure, and the protruding rectangular patch are located on the symmetry axis of the radiation patch.

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