An ultra-wideband circularly polarized implantable package antenna

Abstract

This invention discloses an ultra-wideband circularly polarized implantable packaged antenna, comprising a radiating conductor, a grounding conductor layer, a ceramic substrate, a hermetically sealed bonding ring, a feed TCV center hole, a shielded TCV array, a grounding conductor layer, and RF chip pin pads. This antenna features a compact structure, meeting the small size and low profile requirements of implantable devices; its planar helical design expands the operating bandwidth, enabling ultra-wideband communication; the integrated packaging avoids impedance mismatch associated with traditional soldering, improving signal transmission efficiency and stability, and adapting to complex biological environments; it is easy to manufacture and cost-effective, balancing safety and reliability, solving the problem of balancing size, bandwidth, and performance in existing technologies, and ensuring reliable broadband data transmission.

Description

Technical Field

[0001] This invention relates to an ultra-wideband circularly polarized implantable packaged antenna, belonging to the field of packaged antenna technology. Background Technology

[0002] Implantable antennas are core components of implantable data acquisition and biocontrol terminal data transmission systems, with miniaturization and low profile being their most prominent features. All antennas implanted in biological tissues and organs operate within a biological environment, which is characterized by complex and variable electrical properties; therefore, ultra-wideband operating characteristics are required to cope with harsh working conditions. Encapsulated antennas, based on encapsulation materials and processes, integrate the antenna and chip within a package to achieve system-level wireless functionality, offering the technological advantage of stable and reliable device performance.

[0003] The complex internal environment of living organisms places high demands on the size, corrosion resistance, and safety of implantable antennas. Considering the electromagnetic safety of implantation in the human body, the operating frequency of the antenna should generally not be too high. The operating environment of implantable antennas is within human tissues and organs, whose electrical characteristics differ significantly from free space. Therefore, the antenna must possess broadband characteristics to counteract the influence of the human body. Most existing implantable antennas are linearly polarized antennas, which have inherent limitations such as poor interference rejection capabilities and significant susceptibility to ground reflections, making them unsuitable for flexible application in the complex electromagnetic environment of living organisms. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose an ultra-wideband circularly polarized implantable packaged antenna, which has the advantages of compact structure, high flexibility, low processing difficulty, good anti-interference ability, and wide applicability. It can provide an ultra-wide operating bandwidth to meet high-throughput communication tasks.

[0005] The technical solution of the present invention is: an ultra-wideband circularly polarized implantable packaged antenna, comprising a radiating conductor, a ground conductor layer, a ceramic substrate, a hermetically sealed bonding ring, a feed TCV center hole, a shielded TCV array, a ground conductor layer, and RF chip pin pads; The ceramic substrate comprises two layers: an upper surface, a ceramic insulating layer, a first metal layer beneath the upper surface (the metal wiring layer containing the radiating conductor), a lower surface (a metal layer, i.e., the bottom wiring layer), and a second metal layer on the lower surface (a grounding conductor layer). The feed TCV center hole is located inside the ceramic substrate, connecting the RF chip pin pads to the center feed point on the radiating conductor. The RF chip pin pads are located on the lower surface of the ceramic substrate, i.e., the bottom wiring layer. A hermetically sealed bonding ring is also located on the lower surface of the ceramic substrate, i.e., the bottom wiring layer, encompassing all components with pre-reserved mounting space at the edges to ensure the hermetically sealed encapsulation of the entire module. The grounding conductor... The body layer is a second metal layer located on the lower surface of the ceramic substrate. The vertical distance between the second metal layer on the lower surface and the bottom wiring layer should meet the impedance matching requirements of the microstrip transmission line. The radiating conductor is located in the first metal layer below the upper surface of the ceramic substrate. It is protected by the dielectric insulation layer on the upper surface of the ceramic substrate and is isolated from the outside air or implant. The grounding conductor layer is located in the second metal layer below the upper surface, that is, the layer below the metal layer where the radiating conductor is located. The laying area should at least cover the outer contour area of ​​the radiating conductor. The shielded TCV array is located inside the ceramic substrate, arranged around the central hole of the feed TCV, and connected to the grounding conductor layer and the grounding conductor layer.

[0006] The radiating conductor adopts a planar helical structure.

[0007] The outer diameter of the planar helix D According to the formula Sure, The wavelength corresponding to the lowest operating frequency; inner diameter of the planar helix. , This is the wavelength corresponding to the highest operating frequency.

[0008] The growth rate of the planar spiral ,in w The width of the planar helix. This is the operating wavelength.

[0009] The RF chip pin pads are placed in the middle area of ​​the lower surface of the ceramic substrate, and are positioned horizontally close to the antenna feed point to ensure that the RF signal is transmitted along the shortest path.

[0010] When the number of ceramic substrate layers is less than 4, the horizontal position of the RF chip pin pad on the lower surface of the ceramic substrate overlaps with the horizontal position of the antenna feed point in the radiating conductor. The feed TCV center hole passes vertically through the RF chip pin pad to the antenna feed point to ensure that the RF signal is transmitted along the shortest path.

[0011] When the number of ceramic substrate layers is greater than or equal to 4, the horizontal position of the RF chip pin pad on the lower surface of the ceramic substrate is close to, but does not overlap with, the horizontal position of the antenna feed point in the radiating conductor. The center hole of the feed TCV is offset along the line connecting the RF chip pin pad and the antenna feed point, and arranged in a zigzag staggered manner to ensure that the RF signal is transmitted along the shortest path.

[0012] The central hole of the power-feeding TCV and the surrounding shielded TCV array form a TCV array with a near-coaxial structure.

[0013] The radius of the central hole of the power-fed TCV a The distance between the center point of the feed TCV center hole and the center point of any TCV hole in the shielded TCV array b Satisfying the relation ,in Characteristic impedance; is the relative permittivity of the selected substrate material.

[0014] The advantages of this invention compared to the prior art are: (1) The integrated packaged antenna of the present invention effectively expands the working bandwidth and realizes the ultra-wideband communication of the module by arranging the radiating conductor along the planar spiral structure.

[0015] (2) The structure of the present invention reduces the processing complexity and manufacturing cost. At the same time, by using the integrated preparation of multilayer ceramic substrates, the impedance mismatch problem introduced by traditional welding process is avoided, thereby improving signal transmission efficiency and stability.

[0016] (3) The integrated packaged antenna of the present invention can meet the small size requirements and ensure the reliable transmission of high frequency data, realize the compactness of the antenna structure, and solve the problem that size, bandwidth and security and reliability are difficult to balance in the prior art. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the stacked structure of the ultra-wideband circularly polarized packaged antenna of the present invention; Figure 2 This is a top perspective view of the ultra-wideband circularly polarized packaged antenna of the present invention; Figure 3 This is a bottom perspective view of the ultra-wideband circularly polarized packaged antenna of the present invention; Figure 4 The simulation results of the ultra-wideband circularly polarized packaged antenna of the present invention are shown in the figure. Figure 5 The simulation results of the axial ratio of the ultra-wideband circularly polarized packaged antenna of the present invention are shown (φ=0°). Figure 6The figure shows the axial ratio simulation results (φ=90°) of the ultra-wideband circularly polarized packaged antenna of the present invention. Detailed Implementation

[0018] The present invention provides an ultrawideband circularly polarized implantable packaged antenna, comprising a radiating conductor 1, a grounding conductor layer 2, a ceramic substrate 3, a hermetically sealed solder ring 4, a feed TCV center hole 5, a shielded TCV array 6, a grounding conductor layer 7, and RF chip pin pads 8. The ceramic substrate 3 includes upper and lower surface layers. The upper surface is a ceramic insulating layer; the first metal layer below the upper surface is the metal wiring layer where the radiating conductor 1 is located; the lower surface is a metal layer, i.e., the bottom wiring layer; the second metal layer on the lower surface is the grounding conductor layer 7; the feed TCV center hole 5 is located inside the ceramic substrate 3, connecting the RF chip pin pad 8 and the center feed point on the radiating conductor 1; the RF chip pin pad 8 is located on the lower surface of the ceramic substrate 3, i.e., on the bottom wiring layer; the hermetic sealing ring 4 is also located on the lower surface of the ceramic substrate 3, i.e., on the bottom wiring layer, encompassing all components, with reserved mounting space at the edges to ensure the hermetic encapsulation of the entire module; the grounding conductor... Layer 7 is a second metal layer located on the lower surface of the ceramic substrate 3. The vertical distance between the second metal layer on the lower surface and the bottom wiring layer should meet the impedance matching requirements of the microstrip transmission line. The radiating conductor 1 is located on the first metal layer below the upper surface of the ceramic substrate 3. It is protected by the dielectric insulation layer on the upper surface of the ceramic substrate 3 and is isolated from the outside air or implant. The grounding conductor layer 2 is located on the second metal layer below the upper surface, that is, the layer below the metal layer where the radiating conductor 1 is located. The laying area should at least cover the outer contour area of ​​the radiating conductor 1. The shielded TCV array 6 is located inside the ceramic substrate 3, arranged around the central hole 5 of the feed TCV, and connected to the grounding conductor layer 2 and the grounding conductor layer 7.

[0019] like Figure 1 The diagram shown is a schematic representation of the structure of this invention. The ceramic insulating layer disposed on the upper surface of the ceramic substrate 3 ensures insulation between the encapsulated antenna and biological tissues such as muscle, and also protects the implantable antenna from the corrosive effects of bodily fluids and other biological environments. The radiating conductor 1 (i.e., the antenna) disposed on the lower first metal layer of the upper surface of the ceramic substrate 3 increases the effective radiation radius of the antenna through a planar helical structure, thereby improving the antenna bandwidth. The outer diameter of the planar helical structure... D The perimeter corresponding to the outer diameter can be determined according to the formula. Preliminary determination The wavelength corresponding to the lowest operating frequency; inner diameter of the planar helix. d According to the formula Preliminary determination The wavelength corresponding to the highest operating frequency; the growth rate of the planar spiral. According to the formula Preliminary determination w The width of the planar helix. The operating wavelength is determined and optimized based on the manufacturing plant's process baseline. A higher dielectric constant for the ceramic substrate material is more conducive to antenna miniaturization. The radiating conductor (i.e., the antenna's base layer) located on the first metal layer below the upper surface of the ceramic substrate 3, and the RF chip pin pad 8 located on the lower metal layer of the ceramic substrate 3, form an electrical connection via TCVs to transmit RF signals. This TCV for transmitting RF signals is the antenna feed line, and is electromagnetically shielded and isolated by a surrounding array of shielded TCVs connected to the ground conductor layer, forming a near-coaxial structure with the feed line TCVs. Adaptable to the multilayer structure of ceramic substrates, this design method is highly feasible, has low design difficulty, is easy to optimize and process, and allows for fine-tuning of dimensions to accommodate different operating frequencies. The hermetically sealed weld ring located on the upper surface of the ceramic substrate 3, at the inner edge of the entire module, is connected to the ground conductor layer via multiple sets of TCVs, ensuring the module's hermetically tightness and guaranteeing the functional stability of all internal components after implantation. For this invention, the port impedance of the RF chip is typically 50Ω, and the port impedance of the designed TCV-type coaxial array should be matched with that of the chip. Since the antenna with a planar helical structure has a high input impedance, adding RF chip pin pads changes the impedance at the feed point of the planar helical antenna, causing it to no longer match. The antenna input impedance can be reduced by increasing the width of the planar helix or decreasing the gap width, thereby reducing return loss and improving radiation efficiency.

[0020] To meet the high requirements of implantable electronic packaging systems for antenna size, corrosion resistance, and safety, the dielectric material of the packaged antenna of this invention is a ceramic substrate with excellent electrical properties. To reduce processing difficulty and cost, the packaged antenna of this invention uses a single feed port and a planar spiral as the radiating conductor. To reduce the impact of the radiating antenna on the working circuit, a half-space radiation form is recommended. The antenna radiating structure of this invention has a radiating backplate added to the upper metal layer to improve directivity.

[0021] like Figure 2 As shown in the top perspective view, the specific structure of the packaged antenna is illustrated, including the radiating conductor 1, the feed TCV center hole 5, and the shielded TCV array 6. The feed TCV center hole 5 is located at the starting position of the center of the planar spiral and is connected to the radiating conductor 1 by the RF chip pin pads. The shielded TCV array 6 is connected to the ground conductor layer 2, the layer below the radiating conductor plane, by the ground pin pads of the RF chip, and is arranged in a near-coaxial configuration with the feed TCV center hole 5.

[0022] like Figure 3As shown in the bottom perspective view, the specific structure of the circuitry that provides RF signals to the packaged antenna is illustrated, including the RF chip pin pads 8, the hermetically sealed ring 4, the feed TCV center hole 5, and the shielded TCV array 6. The RF circuitry comprises seven chips / devices; the RF signal is transmitted to the packaged antenna via the feed TCV center hole 5 through the pad hole. The feed TCV center hole 5 and the shielded TCV array 6 together form a quasi-coaxial transmission structure; the hermetically sealed ring 4 is located at the inner edge of the entire module and is connected to the ground conductor layer 7, with all seven chips / devices located inside the hermetically sealed ring.

[0023] like Figure 4 As shown, the specific embodiment of the present invention demonstrates the packaged antenna impedance bandwidth (return loss better than 10dB) and the operating frequency covers an ultra-wideband range of 0.1GHz to 20GHz. The impedance bandwidth of patch antennas using the same substrate material is generally 5%, and the impedance bandwidth of the ultra-wideband circularly polarized antenna in this embodiment is 40 times that of traditional patch antennas.

[0024] like Figure 5 , 6 As shown, the simulation results of the axial ratio of the antenna implemented by the specific embodiments of the present invention in two mutually perpendicular planes (0.1GHz, 1GHz, 5GHz, 10GHz, 20GHz) are respectively displayed. The axial ratio is less than -3dB in a wide angle range of -90° to 90°, and the circular polarization performance is stable in the ultra-wideband range of 0.1GHz to 20GHz, with high transmission and reception efficiency.

[0025] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention based on the above-disclosed technical content without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. An ultra-wideband circularly polarized implantable packaged antenna, characterized in that, It includes a radiating conductor (1), a grounding conductor layer (2), a ceramic substrate (3), a gas-tight welding ring (4), a feed TCV center hole (5), a shielded TCV array (6), a grounding conductor layer (7), and RF chip pin pads (8). The ceramic substrate comprises two layers: an upper surface, a ceramic insulating layer, a first metal layer beneath the upper surface (the metal wiring layer containing the radiating conductor), a lower surface (a metal layer, i.e., the bottom wiring layer), and a second metal layer on the lower surface (a grounding conductor layer). The feed TCV center hole is located inside the ceramic substrate, connecting the RF chip pin pads to the center feed point on the radiating conductor. The RF chip pin pads are located on the lower surface of the ceramic substrate, i.e., the bottom wiring layer. A hermetically sealed bonding ring is also located on the lower surface of the ceramic substrate, i.e., the bottom wiring layer, encompassing all components with reserved mounting space at the edges to ensure the hermetically sealed encapsulation of the entire module. The grounding conductor layer is located on the second metal layer on the lower surface of the ceramic substrate. The vertical distance between the second metal layer on the lower surface and the bottom wiring layer should meet the impedance matching requirements of the microstrip transmission line. The radiating conductor is located in the first metal layer below the upper surface of the ceramic substrate. It is protected by the dielectric insulation layer on the upper surface of the ceramic substrate and is isolated from the outside air or implant. The grounding conductor layer is located in the second metal layer below the upper surface, that is, the layer below the metal layer where the radiating conductor is located. The laying area must at least cover the outer contour area of ​​the radiating conductor. The shielding TCV array is located inside the ceramic substrate, arranged around the central hole of the feed TCV, and connected to the grounding conductor layer and the grounding conductor layer.

2. The ultra-wideband circularly polarized implantable packaged antenna according to claim 1, characterized in that, The radiating conductor adopts a planar helical structure.

3. The ultra-wideband circularly polarized implantable packaged antenna according to claim 2, wherein the outer diameter of the planar helix... D According to the formula Sure, The wavelength corresponding to the lowest operating frequency; inner diameter of the planar helix. , This is the wavelength corresponding to the highest operating frequency.

4. The ultra-wideband circularly polarized implantable packaged antenna according to claim 2, wherein the growth rate of the planar spiral is... ,in w The width of the planar helix. This is the operating wavelength.

5. In the ultra-wideband circularly polarized implantable packaged antenna according to claim 1, the RF chip pin pads are placed in the middle region of the lower surface of the ceramic substrate and are horizontally close to the antenna feed point to ensure that the RF signal is transmitted along the shortest path.

6. In the ultra-wideband circularly polarized implantable packaged antenna according to claim 1, when the number of ceramic substrate layers is less than 4, the horizontal position of the RF chip pin pad on the lower surface of the ceramic substrate overlaps with the horizontal position of the antenna feed point in the radiating conductor, and the feed TCV center hole passes vertically through the RF chip pin pad through the antenna feed point to ensure that the RF signal is transmitted along the shortest path.

7. In the ultra-wideband circularly polarized implantable packaged antenna according to claim 1, when the number of ceramic substrate layers is greater than or equal to 4, the horizontal position of the RF chip pin pad on the lower surface of the ceramic substrate is close to, but does not overlap with, the horizontal position of the antenna feed point in the radiating conductor, and the feed TCV center hole is offset along the line connecting the RF chip pin pad and the antenna feed point, arranged in a zigzag staggered manner to ensure that the RF signal is transmitted along the shortest path.

8. The ultra-wideband circularly polarized implantable packaged antenna according to claim 1, wherein the feed TCV center hole and the surrounding shielded TCV array form a coaxial TCV array.

9. The ultra-wideband circularly polarized implantable packaged antenna according to claim 8, wherein the radius of the center hole of the feed TCV is... a The distance between the center point of the feed TCV center hole 5 and the center point of any TCV hole in the shielded TCV array b Satisfying the relation ,in Characteristic impedance; is the relative permittivity of the selected substrate material.

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