A dielectric-free packaged phased array antenna with wide-angle scanning

Abstract

The present invention provides a dielectric-free packaged phased array antenna with wide-angle scanning, which belongs to the technical field of packaged antennas. The packaged phased array antenna is composed of antenna modules of different sizes, which meet the requirements of expanding the working bandwidth of the phased array antenna in the millimeter wave band, increasing the scanning range and improving the process reliability. The antenna module is composed of multiple antenna units, and the antenna unit adopts a double-slit to expand the bandwidth; the "air + dielectric" back cavity reduces the unit size to increase the scanning range, and the discretized isolation metal columns improve the reliability and stability of the process. The dielectric-free wide-angle scanning packaged phased array antenna proposed by the present invention achieves high radiation efficiency in the millimeter wave band, and at the same time has the advantages of broadband, large angle and high reliability.

Description

Technical Field

[0001] The present invention belongs to the technical field of packaged antennas, and in particular relates to a dielectric-free packaged phased array antenna with wide-angle scanning. Background Art

[0002] Antenna in Package (AiP) describes a specific antenna type in which the antenna radiator is directly integrated into the chip package. Compared to antennas on board (AoB) and on chip (AoC), it can improve the transmission and radiation efficiency of phased array antennas while maintaining the system integration level of phased array antennas. Therefore, phased arrays using the AiP architecture can effectively improve the overall performance of wireless devices such as millimeter-wave radars and 5G communication base stations.

[0003] Due to the limitations of the process system, traditional packaged antennas cannot overcome the dielectric loss of the material. "Dielectric-free" packaging technology provides an effective path to improve the efficiency of packaged antennas. Its precision and ability to form complex and fine structures also ensure its implementation in the millimeter-wave frequency band. This process system requires breaking through traditional design concepts and methods to achieve expanded operating bandwidth, increased scanning range, and improved process reliability. Summary of the Invention

[0004] To address the problems presented by the prior art, the present invention aims to provide a dielectric-free packaged phased array antenna with wide-angle scanning. The antenna unit of this phased array antenna comprises a dielectric-free three-dimensional metal layer and a ceramic substrate. By innovatively designing the antenna unit structure and its corresponding feed unit, and by removing the dielectric, this invention overcomes the dielectric loss associated with conventional packaged antennas. This achieves an expansion of the operating bandwidth, an increase in scanning range, and improved process reliability for the packaged phased array antenna.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A dielectric-free packaged phased array antenna with wide-angle scanning, comprising 2 n An antenna module; the antenna module is composed of m×m antenna units arranged in a field shape;

[0007] The antenna unit includes a dielectric-free three-dimensional metal layer, a ceramic substrate and a feeding structure;

[0008] The dielectric-free three-dimensional metal layer consists of a metal plate and a number of isolated metal columns; the metal plate is rectangular, with a "C"-shaped radiation slot provided on each of its opposite sides, and the two radiation slots are symmetric with respect to the two symmetry axes of the metal plate; a number of rectangular glue-flowing slots are provided at the center of the metal plate, and the long sides of the glue-flowing slots should be in the same direction as the current direction on the metal plate to avoid affecting the working mode of the antenna; the isolated metal columns are uniformly and fixedly provided at the four peripheral edges of the bottom of the metal plate;

[0009] The ceramic substrate includes a dielectric substrate, a first metal layer provided on the upper surface of the dielectric substrate, and a second metal layer provided on the lower surface of the dielectric substrate; the first metal layer is an annular-shaped metal layer, the second metal layer is a rectangular metal layer with circular holes provided thereon; isolation metal vias are provided at the four peripheral edges of the dielectric substrate;

[0010] The size of the ceramic substrate is the same as that of the dielectric-free three-dimensional metal layer;

[0011] The feeding structure includes a feeding metal column with a coaxial central axis, an upper surface metal PAD (pad), a feeding metal via, and a lower surface metal PAD; among them, the upper surface metal PAD is provided on the upper surface of the dielectric substrate, the feeding metal column connects the upper surface metal PAD and the metal plate, the feeding metal via is penetratingly provided in the dielectric substrate, the feeding metal via connects the upper surface metal PAD and the lower surface metal PAD, and the lower surface metal PAD is provided in the circular hole of the second metal layer.

[0012] Further, n is a natural number, and m is a positive integer not less than 2.

[0013] Further, the distance between adjacent two isolated metal columns is 0.4 mm to 1 mm, while ensuring the stability and reliability of the process and that electromagnetic wave leakage does not occur transversely in the antenna unit, causing coupling between antenna units; the shape of the metal column is arbitrary, preferably cylindrical or square-columnar.

[0014] Further, the material of the dielectric substrate is Al2O3, AlN, SiC, etc.

[0015] Further, the second metal layer is provided with an interconnection interface, and through the welding process, the integration and electrical interconnection with the package body of the chip are realized.

[0016] Further, the length of the radiation slot should be slightly greater than half of the free space wavelength at the center frequency point within the working frequency band, and the width is less than 0.1 of the free space wavelength.

[0017] Further, the size of the antenna unit should be less than 0.48 of the free space wavelength at the highest frequency of the working frequency band, so that the antenna meets the requirements of no grating lobes and no blind area scanning in the upper half space.

[0018] Furthermore, the feeding structure should be arranged between the center line of the antenna unit and the radiation slot to ensure impedance matching of the antenna unit.

[0019] Furthermore, when assembling the entire device, necessary assembly gaps should be reserved between antenna modules to prevent integration failure due to processing and assembly errors.

[0020] Furthermore, the antenna unit uses UV-LIGA (Ultra-Violet-Lithographie, Galvanformungand Abformug) process to form a dielectric-free three-dimensional metal layer on the ceramic substrate.

[0021] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0022] The dielectric-free packaged phased array antenna, consisting of 16 antenna elements in a 4 × 4 array within the operating frequency band, has a VSWR (voltage standing wave ratio) of less than 2.2 at its feed port and an aperture efficiency greater than 84%. The array size of the phased array antenna is 15.5 mm × 15.5 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the basic layout of a dielectric-free packaged phased array antenna having several antenna modules of the present invention.

[0024] Figure 2 Schematic diagram of an antenna module consisting of 2×2 antenna units in Example 1 of the present invention.

[0025] Figure 3 Schematic diagram of the structure of the antenna unit of the present invention.

[0026] Figure 4 Schematic diagram of the layering of dielectric-free three-dimensional metal layers in the antenna unit of the present invention.

[0027] Figure 5 Schematic diagram of the layers of the ceramic substrate in the antenna unit of the present invention.

[0028] Figure 6 Schematic diagram of the feeding structure of the antenna unit of the present invention.

[0029] Figure 7 This is the lowest operating frequency pattern of the packaged phased array antenna obtained in Example 1 of the present invention.

[0030] Figure 8 This is the central operating frequency pattern of the packaged phased array antenna obtained in Example 1 of the present invention.

[0031] Figure 9 This is the highest operating frequency radiation pattern of the packaged phased array antenna obtained in Example 1 of the present invention.

[0032] Figure 10 This is a voltage standing wave ratio curve of the four antenna unit ports of the packaged phased array antenna obtained in Example 1 of the present invention.

[0033] Figure 11 This is a radiation efficiency curve of the packaged phased array antenna obtained in Example 1 of the present invention.

[0034] Figure 12 This is a gain curve diagram of the packaged phased array antenna obtained in Example 1 of the present invention.

[0035] Figure 13 Schematic diagram of an antenna module consisting of 2×2 antenna units in Example 2 of the present invention.

[0036] Figure 14 This is the lowest operating frequency radiation pattern of the packaged phased array antenna obtained in Example 2 of the present invention.

[0037] Figure 15 This is the central operating frequency pattern of the packaged phased array antenna obtained in Example 2 of the present invention.

[0038] Figure 16 This is the highest operating frequency radiation pattern of the packaged phased array antenna obtained in Example 2 of the present invention.

[0039] Figure 17 This is a graph showing the voltage standing wave ratio of 16 antenna unit ports of the packaged phased array antenna obtained in Example 2 of the present invention.

[0040] Figure 18 This is a gain curve diagram of the packaged phased array antenna obtained in Example 2 of the present invention.

[0041] Figure 19 This is a radiation efficiency curve of the packaged phased array antenna obtained in Example 2 of the present invention.

[0042] Figure numerals: 101-antenna module, 201-antenna unit, 301-non-dielectric three-dimensional metal layer, 302-ceramic substrate, 401-metal plate, 402-radiation gap, 403-glue flow gap, 404-feed metal column, 405-isolation metal column, 501-first metal layer, 502-upper surface metal PAD, 503-Al2O3 dielectric substrate, 504-isolation metal via, 505-feed metal via, 506-second metal layer, 507-lower surface metal PAD. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the implementation methods and drawings.

[0044] Limited by the process system, traditional packaged antennas are unable to overcome the dielectric loss of the material. "Dielectric-free" packaging technology provides an effective path to improve the efficiency of packaged antennas. Its precision and ability to form complex and fine structures also ensure its implementation in the millimeter-wave frequency band. Under this process system, it is necessary to break through traditional design concepts and methods to achieve the expansion of the operating bandwidth, increase the scanning range, and improve process reliability of packaged phased array antennas.

[0045] The present application provides a dielectric-free packaged phased array antenna with wide-angle scanning, the basic layout diagram of which is shown in FIG. Figure 1 As shown, including 2 n The present invention eliminates the dielectric loss problem associated with conventional packaged antennas by removing the antenna dielectric. The antenna operates in the millimeter wave frequency band and offers advantages such as high radiation efficiency, high integration, and a wide beam scanning range.

[0046] Example 1

[0047] A dielectric-free packaged phased array antenna with wide-angle scanning, the antenna comprising an antenna module; the antenna module is arranged by four antenna units 201 in a 2×2 square topology, and its structural diagram is shown in FIG. Figure 2 As shown in the figure, a feeding structure is set on each antenna unit to feed the antenna unit. The unit spacing is less than 0.48 free space wavelengths of the highest frequency in the operating frequency band, meeting the requirements of large-range scanning of the phased array; the size of the entire antenna module is W1× L1= 7.6 mm × 7.6 mm.

[0048] The structural diagram of the antenna unit is as follows Figure 3 As shown, it includes a dielectric-free three-dimensional metal layer 301 and a ceramic substrate 302;

[0049] The layered schematic diagram of the dielectric-free three-dimensional metal layer is as follows Figure 4 As shown, the metal plate 401 ( Figure 4 Left) and several isolation metal pillars 405 ( Figure 4It consists of (right); the metal plate is rectangular, with a "C"-shaped radiation slot 402 provided on each of its opposite sides. The two radiation slots are symmetric about the two symmetry axes of the metal plate and have opposite openings; three rectangular glue-flowing slots 403 are arranged side by side at the center of the metal plate. The long sides of the glue-flowing slots should be in the same direction as the current direction of the metal plate; the isolation metal columns are uniformly and fixedly arranged on the four peripheral edges of the bottom of the metal plate; the two "C"-shaped radiation slots form a dual-resonant radiator, thereby expanding the working bandwidth of the antenna; the three glue-flowing slots ensure that all the photoresist inside the air cavity can be washed out. At the same time, these slots must be strictly along the radiation current direction to avoid having too much impact on the radiation performance of the antenna unit.

[0050] The schematic diagram of the lamination of the ceramic substrate is as Figure 5 shown, including an Al2O3 dielectric substrate 503 ( Figure 5 middle), and a first metal layer 501 ( Figure 5 left) provided on the upper surface of the dielectric substrate, and a second metal layer 506 ( Figure 5 right) provided on the lower surface of the dielectric substrate; the first metal layer 501 is a rectangular-ring-shaped metal, and the second metal layer 506 is a rectangular metal with circular holes provided thereon; isolation metal vias 504 are provided at the four peripheral edges of the dielectric substrate; the ceramic substrate needs to be made of a single-layer thick-film Al2O3 dielectric substrate; the metal vias inside the dielectric substrate must maintain sufficient spacing, and the metal grounds on the upper and lower surfaces of the ceramic substrate form a complete metal ground through the isolation metal vias.

[0051] The size of the ceramic substrate is the same as that of the dielectric-free three-dimensional metal layer.

[0052] The schematic diagram of the feeding structure is as Figure 6 shown, including a feeding metal column 404, an upper-surface metal PAD 502, a feeding metal via 505, and a lower-surface metal PAD 507 with coaxial central axes; the purpose of ensuring the central coincidence of the various components of the feeding structure is to shorten the feeding path; among them, the upper-surface metal PAD 502 is provided on the upper surface of the dielectric substrate 503, the feeding metal column 404 connects the upper-surface metal PAD 502 and the metal plate 401, the feeding metal via 505 is penetrated and arranged inside the ceramic substrate, the feeding metal via 505 connects the upper-surface metal PAD 502 and the lower-surface metal PAD 507, and the lower-surface metal PAD 507 is provided in the circular hole of the second metal layer 506.

[0053] The isolated metal pillars 405, the first metal layer 501, the isolated metal vias 504, and the surface metal ground 506 form a quasi-SIW (Substrate Integrated Waveguide) "air + dielectric" hybrid cavity, lowering the cavity's resonant frequency and reducing element size, thereby ensuring the antenna's scanning range. The dielectric-free three-dimensional metal layer connected to the top metal surface of the ceramic substrate is composed of multiple separate metal pillars rather than a complete metal wall. This is due to the significant difference in thermal expansion coefficients between copper and ceramic, which can lead to thermal stress mismatch. Discretizing the continuous metal wall into multiple isolated metal pillars reduces thermal stress accumulation, minimizing issues such as cracking of the Al2O3 dielectric substrate and delamination of the dielectric-free three-dimensional metal layer from the ceramic substrate, thereby improving process stability and reliability throughout the entire manufacturing process. According to the aforementioned thermal stress theory, the larger the spacing between the isolated metal pillars, the better, requiring a minimum of 0.4 mm. However, to prevent lateral electromagnetic wave leakage from the antenna elements, which could cause coupling between antenna elements, the spacing between the isolated metal pillars must be no greater than 1 mm.

[0054] Figures 7 to 9 The directional patterns of the packaged phased array antenna obtained in Example 1 of the present invention at the lowest operating frequency, center operating frequency, and highest operating frequency, respectively, are shown. As can be seen from the figure, the directional pattern remains stable at all three frequencies, with essentially identical beamwidths in the E-plane and H-plane, and good axial symmetry maintained within both planes.

[0055] Figure 10 This is a VSWR curve diagram of the four antenna unit ports of the packaged phased array antenna obtained in Example 1 of the present invention. As can be seen from the figure, the in-band VSWR of the four antenna ports is all below 2.5.

[0056] Figure 11 and Figure 12 The radiation efficiency and gain curves of the packaged phased array antenna obtained in Example 1 are shown. When the four antenna ports are excited with equal amplitude and in phase, the antenna gain curve has a gain between 15.0 dBi and 16.4 dBi, and the corresponding radiation efficiency band is between 85% and 97%.

[0057] Example 2

[0058] The dielectric-free packaged antenna of this embodiment includes an antenna module, which is composed of 16 antenna units arranged in a 4×4 square topology. Figure 13 As shown in the figure, the size of the entire antenna module is W2× L2= 15.5 mm × 15.5 mm.

[0059] Figures 14 to 16The directional patterns of the packaged phased array antenna obtained in Example 1 of the present invention at the lowest operating frequency, center operating frequency, and highest operating frequency, respectively, are shown. As can be seen from the figure, the directional pattern remains stable at all three frequencies, with essentially identical beamwidths in the E-plane and H-plane, and good axial symmetry maintained within both planes.

[0060] Figure 17 This is a VSWR curve of the 16 antenna unit ports of the packaged phased array antenna obtained in Example 2 of the present invention. As can be seen from the figure, the in-band VSWR of the four antenna ports are all below 2.3.

[0061] Figure 18 and Figure 19 The following are the gain curve and radiation efficiency curve of the packaged phased array antenna obtained in Example 1 of the present invention. When all 16 antenna ports are excited with equal amplitude and in phase, the antenna gain curve ranges from 9.0 dBi to 9.9 dBi, and the corresponding radiation efficiency band is between 84% and 98%.

[0062] The above description is only a specific embodiment of the present invention. Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or alternative features with similar purposes; all disclosed features, or all steps in the methods or processes, except for mutually exclusive features and / or steps, may be combined in any way.

Claims

1. A dielectric-free packaged phased array antenna with wide-angle scanning, characterized in that: Includes 2 n antenna modules; the antenna module is composed of m×m antenna units arranged in a field shape; n is a natural number, and m is a positive integer not less than 2; The antenna unit includes a dielectric-free three-dimensional metal layer, a ceramic substrate, and a feeding structure; The dielectric-free three-dimensional metal layer consists of a metal plate and a number of isolation metal columns; the metal plate is rectangular, with a "C"-shaped radiation slot provided on each of its opposite sides; the two radiation slots are symmetric about the two symmetry axes of the metal plate; a number of rectangular glue-flow slots are provided at the center of the metal plate, and the long sides of the glue-flow slots should be in the same direction as the current direction on the metal plate to avoid affecting the working mode of the antenna; the isolation metal columns are uniformly and fixedly arranged on the four peripheral edges of the bottom of the metal plate; The ceramic substrate includes a dielectric substrate, a first metal layer provided on the upper surface of the dielectric substrate, and a second metal layer provided on the lower surface of the dielectric substrate; the first metal layer is a rectangular ring-shaped metal layer, the second metal layer is a rectangular metal layer, and a circular hole is provided on the second metal layer; Isolation metal vias are provided at the four peripheral edges of the dielectric substrate; The size of the ceramic substrate is the same as that of the dielectric-free three-dimensional metal layer; The feeding structure includes a feeding metal column with a coaxial central axis, an upper surface metal PAD, a feeding metal via, and a lower surface metal PAD; among them, the upper surface metal PAD is provided on the upper surface of the dielectric substrate, the feeding metal column connects the upper surface metal PAD and the metal plate, the feeding metal via is penetrated and arranged in the dielectric substrate, the feeding metal via connects the upper surface metal PAD and the lower surface metal PAD, and the lower surface metal PAD is arranged in the circular hole of the second metal layer.

2. The dielectric-free packaged phased array antenna according to claim 1, wherein: The distance between adjacent two isolation metal columns is 0.4 mm to 1 mm; the shape of the metal columns is arbitrary.

3. The dielectric-free packaged phased array antenna according to claim 1, wherein: The material of the dielectric substrate is Al2O3, AlN or SiC.

4. The dielectric-free packaged phased array antenna according to claim 1, wherein: The second metal layer is provided with an interconnection interface, and through a welding process, the integration and electrical interconnection with the package body of the chip are achieved.

5. The dielectric-free packaged phased array antenna according to claim 1, wherein: The length of the radiation slot should be greater than half of the free space wavelength at the center frequency point within the working frequency band, and the width is less than 0.1 of the free space wavelength.

6. The dielectric-free packaged phased array antenna according to claim 1, wherein: The size of the antenna unit should be less than 0.48 of the free space wavelength of the highest frequency within the working frequency band.

7. The dielectric-free packaged phased array antenna according to claim 1, wherein: The feeding structure should be arranged between the center line of the antenna unit and the radiation slot to ensure the impedance matching of the antenna unit.

8. The dielectric-free packaged phased array antenna according to claim 1, wherein: During the assembly of the whole machine, an assembly gap should be reserved between the antenna modules.

9. The dielectric-free packaged phased array antenna according to claim 1, wherein: The antenna unit uses the UV-LIGA process to form a dielectric-free three-dimensional metal layer on the ceramic substrate.

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