A w-band broadband packaging metasurface antenna array based on glass via

Abstract

The application discloses a W-band broadband packaging metasurface antenna array based on a glass via, which comprises a one-to-four power divider of a coplanar waveguide structure, a glass via bridge, a vertical electrical transmission glass via, a cross-dipole feeder and a metasurface antenna; after energy is fed in by the coplanar waveguide, the energy is uniformly distributed to four channels through the one-to-four power divider of the glass via bridge, and meanwhile, the parasitic odd mode generated at the discontinuous position of the coplanar waveguide is effectively suppressed, so that the electrical transmission stability and consistency of the feeding network under high frequency are improved; then, the energy is transmitted to the cross-dipole feeder through the vertical electrical transmission glass via, and then the metasurface structure is excited in a coupling mode. In the target frequency band, the antenna realizes a peak gain of 10.8dBi at most, and has good broadband characteristics and radiation performance.

Description

Technical Field

[0001] This invention relates to the application of packaged antennas, and in particular to a W-band broadband packaged metasurface antenna array based on glass through-holes. Background Technology

[0002] With the continuous evolution of communication technology, the demand for higher data transmission rates and lower communication latency is constantly increasing. The W-band, with its advantages of short wavelength, low atmospheric absorption, and abundant available bandwidth, is widely used in long-range high-resolution radar and sensing, millimeter-wave imaging, and is considered an important development direction for future high-frequency communication systems. However, as the frequency increases, the electromagnetic transmission loss between the antenna and the chip increases significantly, leading to a decline in overall system performance. Traditional antenna designs struggle to meet the system's requirements for efficient and highly integrated transmission links. Therefore, integrated antenna technology has gradually become a research focus, mainly including on-chip antennas and packaged antennas. On-chip antennas integrate the antenna and active circuitry onto the same chip, relying on semiconductor materials and manufacturing processes. Therefore, the antenna's size and layout are limited by the chip area and interlayer structure. Furthermore, silicon-based materials generally have high dielectric loss, causing on-chip antennas to typically face performance bottlenecks due to low radiation efficiency. In contrast, packaged antenna technology integrates the antenna structure within a package layer, using independent manufacturing processes to separate the antenna from the chip circuitry, thereby improving the antenna's radiation efficiency and providing greater flexibility in size and layout design. Therefore, this technology is more suitable for communication systems that require both high efficiency and high integration at W-band frequencies.

[0003] Currently, the manufacturing processes commonly used for packaged antennas are mainly divided into two categories: traditional board-level packaging and wafer-level packaging. Wafer-level packaging technology, with its advantages of directly achieving through-hole interconnects during wafer manufacturing without the need for an additional packaging substrate, enables finer feature sizes and higher-density integration, and is gradually becoming the mainstream packaging solution in the high-frequency field. However, similar to on-chip antennas, packaged antennas using silicon through-hole (SiV) technology typically exhibit low radiation efficiency due to the high dielectric loss of silicon-based materials. Based on this, glass through-hole (GHB) technology has emerged as a novel solution, and its excellent electrical performance and low-loss characteristics are gradually becoming a research hotspot. However, existing packaged antenna solutions using this technology suitable for the W-band are few, and due to the limitations of single-layer planar feed networks, most designs are in the form of unit cells or linear arrays. Summary of the Invention

[0004] The purpose of this invention is to provide a W-band broadband packaged metasurface antenna array based on glass vias.

[0005] The technical solution to achieve the purpose of this invention is as follows: a W-band broadband packaged metasurface antenna array based on glass vias, comprising a glass substrate, a first metal structure electroplated on the bottom of the glass substrate, a second metal structure electroplated on the top of the glass substrate, a first glass via for electrical transmission distributed on the glass substrate, and a second glass via for suppressing parasitic modes at discontinuities in the coplanar waveguide; slots are etched on the first metal structure to form a coplanar waveguide structure, and the second metal structure is composed of a dipole feed line, a metasurface, and a glass via connecting bridge.

[0006] Compared with the prior art, the beneficial effects of the present invention are: (1) In view of the lack of planar array related structures in the current W-band packaged antenna design based on glass through-hole, the present invention realizes a 2*2 broadband planar array for the first time based on this process.

[0007] (2) Compared with the previous scheme of using expensive and non-planar air bridges to suppress parasitic modes at the discontinuity of coplanar waveguides, the present invention proposes to use glass through-hole bridges for suppression, thereby realizing a feasible scheme to build a broadband planar antenna array on a single-layer glass substrate, and greatly reducing the cost.

[0008] (3) This invention proposes a basic implementation scheme for the fabrication and packaging of antennas based on glass through-hole technology, and provides a test architecture and measurement method for the return loss and radiation pattern of W-band packaged antennas.

[0009] (4) The present invention operates in the frequency range of 68.5 GHz to 92.0 GHz, and the return loss S11 is always less than -10dB, with a corresponding relative bandwidth of 29.3%. In the target frequency band, the antenna achieves a peak gain of up to 10.8 dBi, with good broadband characteristics and radiation performance, and is suitable for integrated antenna design schemes in high-frequency and high-speed packaged communication systems. Attached Figure Description

[0010] Figure 1 This is a three-dimensional view of a W-band broadband packaged metasurface antenna array based on glass through-holes according to the present invention.

[0011] Figure 2 This is a perspective view of a W-band broadband packaged metasurface antenna element based on glass through-holes according to the present invention.

[0012] Figure 3 This invention represents two developmental stages of an antenna element for a W-band broadband packaged metasurface antenna array based on glass vias.

[0013] Figure 4 The return loss and gain curves of the antenna element of the W-band broadband packaged metasurface antenna array based on glass through-hole are shown in two development stages of this invention.

[0014] Figure 5 The input impedance curves of the antenna element of a W-band broadband packaged metasurface antenna array based on glass vias are shown in two development stages of this invention.

[0015] Figure 6 The return loss and gain curves of the antenna element of the W-band broadband packaged metasurface antenna array based on glass through-hole are shown in two development stages of this invention.

[0016] Figure 7 This invention relates to the extraction and setup of metasurface units in a W-band broadband packaged metasurface antenna array based on glass vias.

[0017] Figure 8 The dispersion curve of the metasurface unit of a W-band broadband packaged metasurface antenna array based on glass through-holes is shown in the present invention.

[0018] Figure 9 This is a three-dimensional view of the feeding network of a W-band broadband packaged metasurface antenna array based on glass through-holes according to the present invention.

[0019] Figure 10 This invention provides an equivalent circuit model of a glass via bridge for a W-band broadband packaged metasurface antenna array based on glass vias.

[0020] Figure 11 This is a simplified circuit model of the T-junction of the feed network for a W-band broadband packaged metasurface antenna array based on glass vias, according to the present invention.

[0021] Figure 12 This paper presents a comparison of the reflection and transmission coefficients between the circuit model simulation and the full-wave simulation of the T-junction of the feed network of a W-band broadband packaged metasurface antenna array based on glass vias, according to the present invention.

[0022] Figure 13 This is a schematic diagram of an overall W-band broadband packaged metasurface antenna array based on glass through-holes according to the present invention.

[0023] Figure 14 This is a schematic diagram illustrating the fabrication process of a W-band broadband packaged metasurface antenna array based on glass through-holes according to the present invention.

[0024] Figure 15 The images show physical photos of the glass wafer obtained from the fabrication of a W-band broadband packaged metasurface antenna array based on glass through-holes, and microscopic images of the packaged antenna array.

[0025] Figure 16 This invention provides a test scheme for the return loss and radiation pattern of a W-band broadband packaged metasurface antenna array based on glass through-holes.

[0026] Figure 17 This paper presents a comparison of return loss in simulation and testing of a W-band broadband packaged metasurface antenna array based on glass vias, as described in this invention.

[0027] Figure 18 This paper presents a comparison of the gain curves from simulation and testing of a W-band broadband packaged metasurface antenna array based on glass vias, as described in this invention.

[0028] Figure 19 This is a comparison diagram showing the difference between the measured standard gain antenna and the measured packaged antenna using different connection structures in a W-band broadband packaged metasurface antenna array based on glass through-holes.

[0029] Figure 20 This is a comparison curve of the insertion loss between the measured standard gain antenna and the measured packaged antenna using different connection structures in the W-band broadband packaged metasurface antenna array based on glass through-holes, according to the present invention.

[0030] Figure 21 Normalized radiation patterns of the E-plane at 75 GHz, 80 GHz, 85 GHz, 90 GHz, 91 GHz, and 92 GHz for simulation and testing of a W-band broadband packaged metasurface antenna array based on glass vias.

[0031] Figure 22 Normalized radiation patterns of the H-plane at 75 GHz, 80 GHz, 85 GHz, 90 GHz, 91 GHz, and 92 GHz for simulation and testing of a W-band broadband packaged metasurface antenna array based on glass vias. Detailed Implementation

[0032] To meet the urgent demands of high-frequency, high-speed communication systems for miniaturization, high integration, and low transmission loss, packaged antennas, as a next-generation RF front-end integration solution, are receiving widespread attention. However, among the wafer-level packaging forms widely used in high-frequency applications, through-silicon via (TSV) technology, due to the use of high-dielectric-loss silicon-based materials, typically results in low antenna gain and poor radiation efficiency, making it difficult to meet the stringent requirements of low-loss radiation, high directivity, and system stability in the W-band. In contrast, glass via (VV) technology, as an emerging solution, demonstrates greater potential and adaptability in packaged antenna applications in the W-band and higher frequency bands due to its precise feature size control, excellent electrical performance, adjustable coefficient of thermal expansion, and process advantages suitable for large-area, low-cost manufacturing.

[0033] This invention provides an implementation scheme for a W-band packaged antenna based on glass through-holes, the packaged antenna structure as follows: Figure 1As shown, this invention mainly consists of a coplanar waveguide 1-to-4 power divider, a glass via bridge, a vertical transmission glass via, a dipole feed line, and a metasurface antenna. After the energy is fed into the bottom coplanar waveguide, the energy is distributed through the 1-to-4 power divider. Simultaneously, the power divider is equipped with a glass via bridge to suppress parasitic modes at discontinuities. Subsequently, the energy from each branch is transmitted to the top-layer dipole feed line through the vertical transmission via, thereby exciting the metasurface structure through coupling.

[0034] This invention employs glass via technology to manufacture a broadband 2*2 metasurface packaged array antenna suitable for the W-band, providing a new solution to the problem of the W-band glass via technology being limited by the single-layer planar feed network.

[0035] First, a coplanar waveguide 1-to-4 power divider is constructed as the feed network, which consists of a glass substrate 1 and a first metal structure 2 electroplated on the bottom of a dielectric substrate, formed by etching grooves 6. Furthermore, this feed network incorporates a glass via 5 for suppressing parasitic modes at discontinuities in the coplanar waveguide structure, and a glass via connecting bridge 9, forming a glass via bridge to suppress parasitic modes generated at the T-junction. Subsequently, at the end of the feed network, energy from the 1-to-4 feed network is vertically transmitted through a first glass via 4 for electrical transmission to four dipole feed lines 7 located on the top metal layer 3, thereby exciting four sets of metasurfaces 8 through coupling, thus forming a 2*2 metasurface packaged array antenna.

[0036] Furthermore, the glass substrate 1 is made of BF33 material, and its overall dimensions are 5.5mm*5.5mm*0.23mm.

[0037] Furthermore, the top and bottom metal structures 3 and 2 of the glass substrate 1 are both made of a four-layer structure of titanium-copper-nickel-gold, with a total thickness of 5µm.

[0038] Furthermore, the first glass through hole 4 and the second glass through hole 5 have an upper diameter of 50µm, a lower diameter of 30µm, and a height of 230µm.

[0039] Furthermore, the slot 6 forms a coplanar waveguide one-to-four power divider structure, wherein the signal line size is 100µm, the slot size is 30µm, and the signal line size after power distribution is 30µm.

[0040] Furthermore, the dipole feed line 7 is composed of two intersecting rectangular microstrips with dimensions of 2.43mm*0.1mm and 1.1mm*0.1mm, respectively.

[0041] Furthermore, the metasurface 8 has dimensions of 0.62mm*0.62mm, and the distance between the metasurface and the dipole feed line 7 is 0.11mm.

[0042] Furthermore, the glass via connecting bridge surface 9 is composed of two circular patches and a rectangular microstrip. The diameter of the circular patches is 70µm, and the size of the rectangular microstrip is 200µm*30µm. The glass via connecting bridge surface 9 and the second glass via 5 used for suppressing parasitic modes at the discontinuity of the coplanar waveguide form a set of glass via bridges to suppress parasitic modes at the discontinuity of the coplanar waveguide power divider.

[0043] The principles of the present invention will now be explained in detail with reference to the accompanying drawings.

[0044] To explore the working principle of this invention, an antenna element was first designed, such as... Figure 2 As shown, the antenna element consists of a coplanar waveguide feed, a vertical transmission glass via 4, a dipole feed 7, and a metasurface element 8. The coplanar waveguide feed has a signal linewidth of 100µm and a slot linewidth of 30µm. The vertical transmission glass via has an upper diameter of 50µm and a lower diameter of 30µm. The dipole feed is composed of two intersecting rectangular microstrips with dimensions of 2.43mm*0.1mm and 1.1mm*0.1mm, respectively. The metasurface element has a size of 0.62mm*0.62mm, and the distance between the metasurface and the dipole feed is 0.11mm. This antenna structure can be constructed from... Figure 3 The two stages shown are explained below. The first stage consists of a dipole antenna, and the second stage adds metasurface units to the first stage. Figure 4 The comparison of return loss and gain between the two stages is shown.

[0045] To further explain the impedance bandwidth expansion mechanism after adding metasurfaces Figure 5 The real and imaginary parts of the input impedance in two stages are shown. Generally, the eigenresonance point appears at the frequency where the real part of the input impedance reaches its extreme value and the imaginary part is zero. As shown in Figure 4, the three eigenresonance points (R1-R3) of the dipole antenna appear at 70 GHz, 79 GHz, and 93 GHz, respectively. Obviously, these three modes are generated by a crossed dipole, and they are defined as dipole mode 1, dipole mode 2, and dipole mode 3.

[0046] After adding metasurface units in stage 2, the cross dipoles and metasurface units form a structure like... Figure 6 The parallel structure is shown. Where, L d and C d L represents the inductance and capacitance of a cross dipole. m C represents the inductance of a metasurface unit. m The coupling capacitance between adjacent units, L g and C gThese correspond to the load capacitance between the unit and the ground, and the dielectric inductance of the grounding structure, respectively. Furthermore, due to the surface wave resonance mode of the metasurface, the resistance remains relatively stable within this frequency range. To further investigate the surface wave resonance mode, according to... Figure 7 The setup shown extracts the dispersion of the metasurface unit. Figure 8 The observation procedure is Γ → X → M → ϒ → Γ. The resonant modes of the surface wave are related to its propagation constant. β sw (x, y) can be calculated using the following formula:

[0047] Where P(x,y) represents the unit period, and N(x,y) represents the number of units. By... Figure 8 By inserting vertical lines corresponding to different values ​​of m, the surface wave resonant frequency can be easily determined at the intersection of the dispersion curve and the vertical line. In this design, N(x) = N(y) = 2. Therefore, we can obtain:

[0048] This yields three sets of surface wave resonant frequencies: 71.4 GHz, 92.1 GHz, and 98.4 GHz, defined as surface wave mode 1, surface wave mode 2, and surface wave mode 3, respectively. After loading the metasurface unit in stage 2, the dipole mode and the surface wave resonant mode will synergize to form four new coupled resonant modes, thereby significantly improving the antenna's impedance bandwidth.

[0049] Subsequent design Figure 9 The feed network shown consists of a glass substrate (1), a coplanar waveguide power divider (3) electroplated on the bottom layer, and a glass via bridge. The glass via bridge is composed of glass vias (5) and glass via connecting bridge surfaces (9). The glass via bridge structure consists of... Figure 10 The equivalent circuit model shown is used for description, where C a R represents the parasitic capacitance between the glass through-hole bridge and the ground plane. a and L a This represents the parasitic resistance and inductance introduced by the glass via connection. To simplify the analysis, based on the above equivalent circuit model and neglecting parasitic effects such as edge capacitance and step discontinuities of the coplanar waveguide, a simplified circuit model of the power divider with a glass via bridge at the T-junction is finally given, as follows: Figure 11 As shown. The impedance of port 1 is set to 50Ω, and the impedances of ports 2 and 3 are set to 100Ω. R a L a and C aThe values ​​are 0.2Ω, 1.02nH, and 0.71 pF, respectively. Circuit simulation of the above equivalent circuit model was performed and compared with the results of full-wave simulation. Figure 12 The diagram shows a comparison between the reflection coefficient and the transmission coefficient. Furthermore, the antenna elements are integrated using a 1-to-4 power divider as the feed network to obtain... Figure 13 The 2x2 metasurface packaged array antenna shown.

[0050] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Example

[0051] Reference Figure 13 This is a schematic diagram of the W-band packaged antenna array structure based on glass vias implemented in this invention. The structure is fed by GSG probes. The energy is fed into the coplanar waveguide transmission line by the GSG probes, and then evenly distributed to the four branches by a 1-to-4 power divider. Subsequently, the energy is transmitted to the dipole feed line on the top layer through four vertical transmission glass vias to excite the metasurface structure and achieve directionally stable radiation characteristics in a wide frequency band.

[0052] Reference Figure 14 This is a flowchart illustrating the fabrication process of a packaged antenna using glass via technology, which mainly includes six steps: 1. Selectively inducing modification of the glass wafer using an ultrashort pulse laser to form continuous modified regions at designated locations; 2. Etching the modified regions with hydrofluoric acid solution to obtain glass vias; 3. Depositing seed layers and adhesion layers on both sides of the glass wafer using magnetron sputtering physical vapor deposition; 4. Defining the circuit pattern by coating the seed layer with photoresist and then using step-by-step lithography; 5. Forming redistribution layers on both sides of the wafer and filling the vias using chemical electroplating, followed by removing the photoresist and unwanted seed layer areas by wet etching; 6. Depositing a nickel-gold layer on the circuit surface as a protective layer to protect the circuit.

[0053] Reference Figure 15 The images show the actual glass wafer obtained from the fabrication process and a microscope image of the packaged antenna array. The glass wafer has a diameter of 152.4 mm and a thickness of 230 µm, while the packaged antenna array measures 5.5 mm * 5.5 mm * 0.23 mm.

[0054] Reference Figure 16This document describes a test scheme for the return loss and radiation pattern of a packaged antenna operating in the W-band. The return loss test setup includes a vector network analysis (VNA), a microscope, a frequency multiplier, a vacuum adsorption device, and a GSG probe. For back-fed packaged antennas, a batch of custom-made foam boards with a dielectric constant of approximately 1 and a small hole at the center are required as an isolation device. During testing, the antenna position is fixed using a vacuum adsorption fixture under a microscope, and then the knob is rotated to precisely position the GSG probe to the antenna feed point. Compared to the return loss test setup, the radiation pattern test setup uses a vacuum adsorption fixture made of foam with a dielectric constant of approximately 1, and adds a robotic arm that can rotate freely in all directions. A horn antenna is mounted on the robotic arm to receive electromagnetic waves radiated from the antenna under test in the far field. During testing, the GSG probe is precisely brought into contact with the feed point under a microscope, and then the robotic arm rotates the horn antenna to receive the electromagnetic waves radiated by the antenna under test. Finally, the antenna gain is calculated by comparing the voltage level of the tested antenna with that of a standard horn antenna.

[0055] Reference Figure 17 This is a comparison chart of simulated and measured return loss for the packaged antenna. The simulated return loss is less than -10dB in the frequency range of 68.5 GHz to 102 GHz, and the measured results are basically consistent in this frequency range.

[0056] Reference Figure 18 To compare the simulated and measured gain of the packaged antenna, the test frequency band was limited to 75-92GHz due to the limitations of the test platform. It can be observed that the simulated and measured trends are basically consistent, and the numerical differences are mainly due to... Figure 19 The difference shown is due to the different insertion loss between the connection devices used when measuring the standard gain antenna and the packaged antenna in the actual measurement. The differences in each part are caused by the reference. Figure 20 In addition, there is an insertion loss of approximately 0.9 dB at the two connectors of the coaxial cable.

[0057] Reference Figure 21 and reference Figure 22 Normalized radiation patterns for the E-plane and H-plane at 75 GHz, 80 GHz, 85 GHz, 90 GHz, 91 GHz, and 92 GHz are presented, showing that the simulation and measurement results are largely consistent. However, due to limitations of the test platform, the robotic arm can only rotate within the range of θ = -180° to 45°, resulting in a test range for the E-plane radiation pattern of θ = 0° to 225°. Furthermore, when the antenna operates beyond 92 GHz, the E-plane will generate significant sidelobes. Therefore, the final operating frequency band of the packaged antenna is set at 68.5 GHz–92 GHz, with a relative gain bandwidth of 29.3%.

[0058] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A W-band broadband packaged metasurface antenna array based on glass through-holes, characterized in that, The structure includes a glass substrate (1), a first metal structure (2) electroplated on the bottom of the glass substrate (1), a second metal structure (3) electroplated on the top of the glass substrate (1), a first glass via (4) distributed on the glass substrate (1) for electrical transmission, and a second glass via (5) for suppressing parasitic modes at the discontinuity of the coplanar waveguide. A slot (6) is etched on the first metal structure (2) to form a coplanar waveguide structure. The second metal structure (3) is composed of a dipole feed line (7), a metasurface (8), and a glass via connecting bridge (9). The glass via connecting bridge (9) is composed of two circular patches and a rectangular microstrip. The glass via connecting bridge (9) and the second glass via (5) for suppressing parasitic modes at the discontinuity of the coplanar waveguide form a set of glass via bridges to suppress parasitic modes at the discontinuity of the coplanar waveguide power divider.

2. The W-band broadband packaged metasurface antenna array based on glass through-holes according to claim 1, characterized in that, The diameter of the circular patch is 70µm, and the size of the rectangular microstrip is 200µm*30µm.

3. The W-band broadband packaged metasurface antenna array based on glass through-holes according to claim 1, characterized in that, The slot (6) forms a coplanar waveguide one-to-four power divider structure, wherein the signal line size is 100µm, the slot size is 30µm, and the signal line size after power distribution is 30µm.

4. The W-band broadband packaged metasurface antenna array based on glass through-holes according to claim 1, characterized in that, The dipole feed line (7) consists of two intersecting rectangular microstrips with dimensions of 2.43mm*0.1mm and 1.1mm*0.1mm, respectively.

5. The W-band broadband packaged metasurface antenna array based on glass through-holes according to claim 1, characterized in that, The metasurface (8) has a size of 0.62mm*0.62mm, and the distance between the metasurface (8) and the dipole feed line (7) is 0.11mm.

6. The W-band broadband packaged metasurface antenna array based on glass through-holes according to claim 1, characterized in that, The first metal structure (2) and the second metal structure (3) are both made of a four-layer structure of titanium-copper-nickel-gold with a total thickness of 5µm.

7. The W-band broadband packaged metasurface antenna array based on glass through-holes according to claim 1, characterized in that, The first glass through-hole (4) for electrical transmission has an upper diameter of 50µm, a lower diameter of 30µm, and a height of 230µm.

8. The W-band broadband packaged metasurface antenna array based on glass through-holes according to claim 1, characterized in that, The second glass via (5) used for suppressing parasitic modes at discontinuities in coplanar waveguides has an upper diameter of 50µm, a lower diameter of 30µm, and a height of 230µm.

9. The W-band broadband packaged metasurface antenna array based on glass through-holes according to claim 1, characterized in that, The glass substrate (1) is made of BF33 and has a size of 5.5mm*5.5mm*0.23mm.

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