Three-dimensional implantable mimo antenna for bio-telemetry applications

Abstract

The application discloses a three-dimensional implantable MIMO antenna for biological telemetry, which is suitable for capsule endoscopy and leadless pacemaker. The system is composed of four antenna units, each unit including a radiation patch, a ground plane, a feed port and a short circuit structure. The symmetric topology of the radiation patch and the strategic layout of the feed / short circuit needles realize self-decoupling, which can effectively reduce the mutual coupling without external decoupling elements. The antenna can work stably at 1.3975 GHz and 2.45 GHz frequency bands, and keep good reflection coefficient, gain and radiation pattern under different tissue environments and implantation depth changes. SAR evaluation shows that it meets the IEEE C95.1-2019 standard, ensuring safety. The three-dimensional structure provides multi-directional radiation diversity, realizing isotropic coverage and robust communication. High-speed telemetry experiments show that it can support up to 100 Mbps data transmission within 10-15 m, which is suitable for complex environments such as continuous motion, attitude change and deep implantation, realizing robust communication and efficient energy transmission.

Description

Technical Field

[0001] This invention belongs to the field of wireless biomedical devices and implantable antennas, specifically relating to a three-dimensional implantable MIMO antenna for biological telemetry applications. It is applied to implantable medical devices such as capsule endoscopes and leadless pacemakers, and can provide enhanced radiation diversity, stable multi-band resonance, reduced inter-unit mutual coupling, and reliable wireless communication in heterogeneous biological tissue environments. Background Technology

[0002] Wireless biomedical devices, including capsule endoscopes and leadless pacemakers, require reliable wireless communication within the body for data and energy transfer. Implantable antennas for such devices must be able to operate efficiently in the high-loss environment of biological tissue while maintaining a miniaturized size suitable for fully encapsulated devices.

[0003] Traditional implantable antennas typically suffer from limited bandwidth, reduced radiation efficiency, and detuning issues due to the heterogeneity of surrounding biological tissue. Single antenna elements often struggle to provide sufficient communication reliability, especially in dynamic environments or deep tissue implantation conditions. Furthermore, miniaturizing antennas to meet implantation requirements often introduces significant losses and presents challenges in achieving multi-band operation, which is crucial for supporting various wireless communication protocols.

[0004] Although multiple-input multiple-output (MIMO) antenna systems have been proposed to improve data rates and spatial diversity performance, existing planar MIMO designs typically exhibit directional radiation characteristics, thus limiting their ability to achieve effective omnidirectional coverage in in-body applications. Furthermore, the close arrangement of multiple antenna elements can easily lead to strong mutual coupling effects, reducing isolation, degrading signal quality, and limiting the overall performance of the wireless telemetry system.

[0005] Existing solutions for suppressing coupling, such as introducing stubs, neutral wires, defective grounding structures, and external inductors, typically increase antenna size, manufacturing complexity, and system integration difficulty, especially in three-dimensional structures suitable for implantable devices. These limitations highlight the urgent need for a compact MIMO antenna that requires no external components, possesses self-decoupling capabilities, and can achieve high isolation and stable multi-frequency operation.

[0006] Therefore, there is an urgent need for an implantable antenna that integrates miniaturization, multi-band operation, high isolation, radiation diversity, and safety compliance. This type of antenna can improve communication reliability, achieve high-speed data transmission, and enhance wireless power transmission capabilities while meeting the space and structural limitations of capsule-shaped and cardiac implantable devices, thus better serving biomedical implantable devices. Summary of the Invention

[0007] To address the aforementioned issues, this invention discloses a three-dimensional implantable multiple-input multiple-output (MIMO) antenna for biological telemetry applications. It combines miniaturization, dual-frequency operation, quasi-omnidirectional radiation characteristics, and radiation diversity. The combination of slotted and short-circuit pin structures, optimized ground plane, and three-dimensional layout achieves self-decoupling, high isolation, and reliable in-vivo wireless communication.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: A three-dimensional implantable MIMO antenna for bio-telemetry applications includes: a dielectric substrate; a radiating patch disposed on one side of the dielectric substrate; a ground plane disposed on the other side of the dielectric substrate; a feed port electrically connected to the radiating patch; and a shorting pin electrically connecting the radiating patch to the ground plane. The radiating patch is generally approximately square and includes a first rectangular slot extending along a first axis and a second rectangular slot extending along a second axis and intersecting the first rectangular slot, thereby forming orthogonal current paths.

[0009] The radiating patch also includes additional rectangular slots symmetrically arranged along its edge, thereby dividing the radiating patch into four identical regions, wherein the power supply port is located in the fourth region and the shorting pin is located in the opposite second region, thereby forming a balanced current distribution on the radiating patch.

[0010] The grounding plane also includes a slotted structure disposed at the corresponding power supply port and short-circuit pin position. The slotted structure is used to adjust the current distribution on the grounding plane, thereby achieving impedance matching optimization and dual-frequency resonance.

[0011] To achieve more precise antenna tuning at the target operating frequency, a rectangular slot is created in the ground plane, located on the opposite side of the feed port and the shorting pin. This rectangular slot alters the surface current distribution path on the ground plane and the antenna's resonant characteristics, thereby enabling finer adjustment of the antenna's impedance matching. With this simple modification to the antenna structure, the antenna can resonate at both 1.3975 GHz and 2.45 GHz, achieving dual-band operation.

[0012] As a further supplement to the present invention, the rectangular slots on the radiating patch are introduced in a progressive manner, wherein the first rectangular slot is used to establish the main resonant path and the second rectangular slot is used to introduce orthogonal current paths to achieve independent tuning of multiple resonant frequencies.

[0013] As a further supplement to the present invention, the symmetrical arrangement of the slots and the relative positions of the power supply port and the shorting pin enable electrical balance inside the radiating patch, thereby improving impedance matching and enhancing radiation stability.

[0014] As a further supplement to the present invention, the slots on the ground plane and the slots on the radiating patch cooperate with each other to further enhance the dual-frequency operation capability and broaden the effective operating frequency band of the antenna unit.

[0015] To further achieve the above objectives, the present invention also provides a three-dimensional implantable multiple-input multiple-output antenna assembly, which includes four antenna elements as described above, wherein each antenna element is disposed on a different surface of a three-dimensional structure.

[0016] As a further supplement to the antenna assembly, four identical antenna elements are arranged on the outer surface of an approximately three-dimensional structure. Each antenna element is oriented differently relative to its adjacent elements, so that its radiation direction is distributed in different spatial directions, thereby achieving radiation diversity.

[0017] As a further supplement to the antenna assembly, the arrangement of the feed ports, shorting pins and slotted structures between each antenna element allows the current polarity between adjacent antenna elements to be naturally reversed, thereby achieving self-decoupling and effectively reducing mutual coupling without the need for additional decoupling structures or increased element spacing.

[0018] As a further supplement to the antenna assembly, the antenna assembly also includes a cover layer disposed above each radiating patch, the cover layer having a dielectric constant substantially the same as that of the dielectric substrate, thereby reducing unwanted electromagnetic coupling with the internal circuitry of the device and improving operational stability in biological environments.

[0019] As a further complement to the antenna assembly, both the dielectric substrate and the capping layer are made of high dielectric constant materials to achieve miniaturization of the antenna while maintaining radiation efficiency.

[0020] The present invention also provides an implantable biomedical device comprising the above-mentioned three-dimensional multiple-input multiple-output antenna assembly, wherein the antenna assembly is integrated into a compact device structure including electronic circuits, sensors and power supply, for realizing reliable wireless communication and power transmission.

[0021] The beneficial effects of this invention are: The antenna proposed in this invention achieves dual-frequency operation while maintaining a compact size through a combination of radiating patch slots and ground plane slots. The symmetrical configuration of the radiating structure and the rational arrangement of the feed port and shorting pin achieve a balanced current distribution and stable radiation characteristics. The three-dimensional arrangement of multiple antenna elements provides near omnidirectional radiation coverage and improves spatial diversity performance. In addition, the inherent self-decoupling mechanism eliminates the need for additional isolation structures, thereby maintaining high isolation performance while reducing design complexity and size. At the same time, this antenna exhibits stable performance in high-loss biological tissues and meets safety standards, making it suitable for high-speed bio-telemetry and wireless power transmission in implantable medical devices. Attached Figure Description

[0022] Figure 1 The structure of a single antenna element includes: (a) a top dielectric layer diagram, (b) a radiating patch diagram, (c) a substrate diagram, (d) a ground plane diagram, and (e) a side view of the antenna.

[0023] Figure 2 A three-dimensional MIMO system diagram; Figure 3 Simulated scattering parameters of a 3D MIMO antenna: Figure 4 Here is a graph showing the measured performance of a 3D MIMO antenna: Figure 5 The normalized radiation patterns of the three-dimensional MIMO structure at two resonant frequencies are shown: (a) 1.3975 GHz (b) 2.45 GHz. Figure 6 This is a three-dimensional radiation pattern of the far field of a three-dimensional MIMO antenna. Figure 7 This is the equivalent circuit diagram of a three-dimensional MIMO antenna.

[0024] Explanation of reference numerals in the attached figures: First horizontal patch slot 1a, first vertical patch slot 1b, second vertical slot 2a on the left side of the patch, second horizontal slot 3a on the top of the patch, third vertical slot 2b on the right side of the patch, third horizontal slot 3b on the bottom of the patch, shorting pin cylinder 4a on the patch surface, port cylinder 4b on the patch surface, rectangular slot 5a on the ground plane, port 5b, cover layer 6a, radiating patch 7a, dielectric substrate 6b, ground plane 7b, shorting pin cylinder 8a, port position 9a and port cylinder 8b, shorting pin cylinder structure 9b located on the ground plane surface. Detailed Implementation

[0025] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0026] As shown in the figure, this invention discloses a compact dual-band three-dimensional multiple-input multiple-output (3D MIMO) antenna for wireless implantable biomedical devices, including capsule endoscopy systems and leadless pacemakers. The antenna is designed to operate at two target frequencies, 1.3975 GHz and 2.45 GHz, while achieving miniaturization, high isolation, radiation diversity, and biocompatibility to ensure safe implantation into human tissue.

[0027] The antenna is integrated into a capsule-type biomedical device, such as an inflatable capsule endoscope and a leadless pacemaker. These capsules are cylindrical and sized for implantation in the human body.

[0028] The capsule structure is made of biocompatible materials, and its internal electronic components, including a battery, sensors, electrodes, and a camera, are arranged on a dielectric substrate. The three-dimensional multiple-input multiple-output antenna is integrated within it, forming a compact and fully integrated implantation system.

[0029] The capsule shell is made of alumina (Al2O3) ceramic with a dielectric constant of [missing information]. The strength is 9.8, the loss tangent tanδ is 0.006, and the thickness is 0.25 mm to ensure biocompatibility.

[0030] The dielectric substrate was modeled using Rogers RT / duroid 6010 material, with dielectric constant... The loss tangent tanδ is 0.0023, and it is sandwiched between two layers of ideal electrical conductors (PEC). This configuration facilitates realistic simulation of the antenna's electromagnetic performance in an implanted environment.

[0031] Antenna performance was evaluated in both homogeneous and heterogeneous tissue models. The homogeneous model used a small intestine simulator with dimensions of 100×100×100 mm³, enclosed by a radiating boundary of 200×200×200 mm³, with an antenna implantation depth of 50 mm. The model considered the frequency-dependent dielectric properties of the tissue, enabling accurate simulation of antenna behavior in a human tissue environment using a high-frequency structural simulator (HFSS).

[0032] In the simulation of heterogeneous tissues, Sim4Life software was used to model the specific dielectric properties of each tissue at the operating frequency. The simulated reflection coefficients of both homogeneous and heterogeneous models were in high agreement with the experimental measurements, verifying the dual-frequency resonance accuracy of the antenna in a real implantation environment and the minimum mutual coupling performance between adjacent units.

[0033] Reference Figure 1 The antenna assembly provided in this embodiment of the invention includes: a first horizontal patch slot 1a, a first vertical patch slot 1b, a second vertical slot 2a on the left side of the patch, a second horizontal slot 3a on the top of the patch, a third vertical slot 2b on the right side of the patch, a third horizontal slot 3b on the bottom of the patch, a short-circuit pin cylinder 4a on the patch surface, a port cylinder 4b on the patch surface, a rectangular slot 5a on the ground plane, a port 5b, a cover layer 6a, a radiating patch 7a, a substrate 6b, a ground plane 7b, a short-circuit pin cylinder 8a, a port position 9a and a port cylinder 8b, a short-circuit pin cylinder structure 9b located on the ground plane surface, a cross-section line 10a, a short-circuit pin cylinder 11a disposed on the substrate surface, and a feed port cylinder 11b disposed on the substrate surface.

[0034] In this embodiment, the radiating patch 7a achieves dual-frequency operation and reduces mutual coupling through a multi-rectangular slot arrangement. Specifically, it includes: a first horizontal slot 1a at the center of the patch, a first vertical slot 1b at the center of the patch, a second vertical slot 2a on the left side of the patch, a second horizontal slot 3a at the top of the patch, a third vertical slot 2b on the right side of the patch, and a third horizontal slot 3b at the bottom of the patch. A shorting pin cylinder 8a electrically connects the radiating patch 7a to the ground plane 7b, and its position can be located at the center or upper right corner of the second region. Port 5b is coupled to the radiating patch 7a through port cylinder 8b, located at the center or bottom of the fourth region. The rectangular slot 5a on the left side of the ground plane 7b is used to improve impedance matching and enhance dual-frequency resonance. Port cylinder 8b electrically connects port 5b to the radiating patch 7a, completing the excitation path. The radiating patch 7a is mounted on the substrate 6b and covered by a capping layer 6a to provide biocompatibility and reduce interference to components inside the capsule. All of the above components together form a compact dual-frequency antenna structure suitable for integration into implantable biomedical devices.

[0035] Design Principle: Six slots are symmetrically cut on the radiating patch 7a to create a symmetrical current distribution structure, allowing for greater design freedom in the positions of the feed port and shorting pin. The mutually perpendicular horizontal and vertical slots at the center, along with the four rectangular slots located along the four edge regions of the antenna plane, together form a symmetrical structure, thereby effectively controlling the current distribution on the antenna surface.

[0036] When multiple antenna elements form a three-dimensional cube structure, the positions of the feed ports and shorting pins of each element can be adjusted to make the main current directions in adjacent elements opposite. Since adjacent antenna elements share a common connection edge, when the current flows in opposite directions, a current cancellation effect will occur, thereby suppressing the propagation of coupled current between elements, reducing mutual coupling between antenna elements, and improving isolation.

[0037] Therefore, the six slots not only facilitate flexible control of antenna current distribution, but also provide a basis for the reverse current design of adjacent units in a three-dimensional cubic MIMO antenna, thereby effectively reducing electromagnetic coupling between units.

[0038] The design of the single antenna element has been optimized in multiple stages to achieve dual-frequency operation, precise resonant frequency tuning, high reflection coefficient and low inter-element mutual coupling, making it suitable for deployment in three-dimensional multi-input multi-output configurations.

[0039] In the initial design phase, the antenna was a square radiating patch with a single horizontal rectangular slot, a complete ground plane, and a shorting pin placed on the opposite side of the feed port. This configuration produced resonance at 2.85 GHz with |S11| below −25 dB.

[0040] In the second design phase, a vertical rectangular slot of the same size as the horizontal slot was added to the patch, and the resonant frequency was adjusted to approximately 2.43 GHz, while keeping |S11| below −12 dB.

[0041] In the third design phase, the radiating patch was further modified to achieve multi-frequency operation, generating resonances at 1.31 GHz, 2.50 GHz, and 3.27 GHz, corresponding to |S11| of −15 dB, −17 dB, and −13 dB, respectively. Although the third resonant frequency exceeds the target frequency band, this structural modification forms a four-directionally symmetrical radiating patch, which is crucial for reducing mutual coupling in a three-dimensional MIMO configuration and allows for strategic placement of coaxial feed ports and shorting pins in the four quadrants, while also allowing the ground plane to be rotated to maintain electrical balance among the antenna elements.

[0042] In the final design phase, additional rectangular slots were introduced on the ground plane adjacent to the feed port and the shorting pin to achieve precise dual-band tuning of the antenna at 1.3975 GHz and 2.45 GHz, corresponding to |S11| of −26.76 dB and −38.23 dB, respectively.

[0043] Throughout the design process, the antenna maintained its linear polarization characteristics. The reflection coefficients obtained from simulations in homogeneous and heterogeneous tissue models were in high agreement with experimental measurements, verifying the frequency tuning accuracy and reliable performance in actual implantation environments.

[0044] The antenna is implemented on a Rogers RT / duroid 6010 high-dielectric substrate with a dielectric constant of [missing information]. The loss tangent tanδ is 0.0023, the thickness is 0.13 mm, and a cover layer of the same material is placed on top of the patch to provide biocompatibility and reduce interference with the electronic components inside the capsule.

[0045] The patch is excited by a coaxial feed with a diameter of 0.6 mm and an impedance of 50 Ω. Surface current distribution analysis shows that the highest current occurs near the feed port and the shorting pin, providing guidance for optimizing antenna layout in a three-dimensional MIMO configuration.

[0046] The antenna element parameters are as follows: patch length and width 4.6mm, horizontal and vertical slot length 1.8mm, slot width 0.25mm, gap between edge slot and patch 0.27mm; substrate and cover layer thickness 0.13mm each; shorting pin and feed cylinder diameter 0.3mm, coaxial port diameter 0.6mm. Detailed geometric parameters are shown in Table 1.

[0047] Table 1 Geometric parameters of a single antenna element The unit antenna design extends into a three-dimensional multiple-input multiple-output (MIMO) system by mounting four identical antenna elements on the four orthogonal surfaces of a hollow cube. The cube measures 4.6 × 4.6 × 4.6 mm³, the total MIMO antenna assembly measures 5.12 × 5.12 × 4.6 mm³, and the total volume is 120.58 mm³, compact enough for integration into a capsule-shaped device. Two opposing surfaces of the cube remain open to accommodate internal circuitry and other capsule components.

[0048] The antenna is mounted on an orthogonal surface, resulting in quasi-omnidirectional radiation and spatial diversity in all directions. This layout ensures that the high-current region of a single antenna element coincides with the low-current region of an adjacent antenna, creating current reversal and thus inherently reducing mutual coupling. This decoupling requires no additional external components. The symmetrical structure of the radiating patch and the strategic arrangement of the feed port and shorting pins enable the antenna to maintain low interference even in dual-band operation.

[0049] The three-dimensional MIMO antenna system exhibits excellent isolation, with mutual coupling below -25 dB at 1.3975 GHz and below -20 dB at 2.45 GHz. Surface current distribution analysis confirms that the high-current regions of each element are aligned with the low-current regions of neighboring elements, achieving effective intrinsic decoupling. The four-element configuration provides quasi-omnidirectional coverage, low envelope correlation coefficient, high diversity gain, and minimal channel capacity loss, ensuring reliable in-body wireless communication.

[0050] The impact of antenna implantation depth on performance was systematically analyzed. When the implantation depth increased to 100 mm, the antenna gain decreased relatively as the depth decreased due to increased attenuation caused by high-water-content tissues (such as the small intestine). However, even in deep tissue environments, the antenna could still function normally, enabling deep communication.

[0051] An equivalent circuit model was established, with each antenna element represented by an impedance-matched RLC network. The model considers the mutual coupling effect between elements in the three-dimensional MIMO system through series inductors and capacitors.

[0052] The circuit parameters are as follows: C1=0.91pF, C2=C3=0.5pF, L1=14.4nH, L2=8.42nH, L3=2.2nH, R1=3.5 Ω, L4=0.37nH, C4=0.63pF, L5=2nH. This equivalent circuit verifies the dual-frequency resonance and inter-unit mutual coupling characteristics, which are consistent with the full-wave simulation results, providing a reliable basis for the design optimization of three-dimensional MIMO antenna systems.

[0053] Specific Absorption Rate (SAR) safety assessments were conducted using heterogeneous human body sculptors, including the heart, stomach, small intestine, and large intestine. Under an input power of 1 W, the SAR values ​​remained below the limits of the IEEE C95.1-2019 standard (1.6 W / kg for 1-g tissue, 2 W / kg for 10-g tissue), validating the safety of the antenna in implantable biomedical applications.

[0054] Wireless telemetry performance was evaluated through theoretical link budget calculations and experimental measurements using a saltwater simulator in conjunction with a Universal Software Radio Peripheral (USRP).

[0055] The three-dimensional MIMO antenna supports reliable high-speed data transmission, achieving a data rate of 100 Mbps within a 10m range at 1.3975 GHz and within a 15m range at 2.45 GHz. Experimental verification shows that the received power exceeds −100 dBm within a 3m range, indicating that the antenna is suitable for practical in-cell communication. Figure 6 As shown, Figure 6 (a) is a three-dimensional radiation pattern at a frequency of 1.3975 GHz. Figure 6 (b) is a three-dimensional radiation pattern at a frequency of 2.45 GHz.

[0056] MIMO channel analysis confirmed excellent performance parameters, including an envelope correlation coefficient below 0.2 at 1.3975 GHz, below 0.1 at 2.45 GHz, diversity gain exceeding 9 dB, channel capacity loss below 0.12 b / sec / Hz, total active reflection coefficient below −10 dB, and VSWR below 2. These results demonstrate that the antenna possesses high isolation, efficient dual-band operation, and robust performance under implantation conditions.

[0057] In summary, the three-dimensional MIMO antenna system provided by this invention features a compact design, dual-band operation, quasi-omnidirectional radiation characteristics, and radiation diversity. It is also biocompatible and suitable for implantation in human tissue. The combination of slotted and short-circuit pin structures, optimized ground plane, and three-dimensional layout achieves self-decoupling, high isolation, and reliable in vivo wireless communication. This antenna system is particularly suitable for advanced biomedical devices, including capsule endoscopy systems and leadless pacemakers, supporting high-speed telemetry and maintaining stable operation at different implantation depths, locations, and tissue types.

[0058] It should be noted that the above content merely illustrates the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, various improvements and modifications can be made without departing from the principle of the present invention, and all such improvements and modifications fall within the scope of protection of the claims of the present invention.

Claims

1. A three-dimensional implantable MIMO antenna for biological telemetry applications, characterized in that: Includes four antenna elements; And a three-dimensional support structure, the antenna operates in the 1.3975 GHz and 2.45 GHz frequency bands, wherein a single antenna element includes: a dielectric substrate, a radiating patch disposed on one side of the dielectric substrate, a ground plane disposed on the other side of the dielectric substrate, a feed port electrically connected to the radiating patch, and a short-circuit pin electrically connecting the radiating patch to the ground plane; The radiating patch is approximately square in shape and includes a first rectangular slot extending along a first axis and a second rectangular slot extending along a second axis and intersecting with the first rectangular slot, thereby forming an orthogonal current path. The radiating patch also includes additional rectangular slots symmetrically arranged along its edge, thereby dividing the radiating patch into four identical regions, wherein the power supply port is located in the fourth region and the short-circuit pin is located in the second region opposite to it, thereby forming a balanced current distribution on the radiating patch. The grounding plane has a rectangular slot on the left and a slotted structure on the right side, which is located at the corresponding power supply port and short-circuit pin position. The slotted structure is used to adjust the current distribution on the grounding plane, thereby achieving impedance matching optimization and dual-frequency resonance.

2. The three-dimensional implantable MIMO antenna for biological telemetry applications according to claim 1, characterized in that: The rectangular slots on the radiating patch are introduced in a progressive manner, wherein the first rectangular slot is used to establish the main resonant path, and the second rectangular slot is used to introduce orthogonal current paths to achieve independent tuning of multiple resonant frequencies.

3. A three-dimensional implantable MIMO antenna for biological telemetry applications according to claim 1, characterized in that: The four antenna elements are respectively disposed on different surfaces of the three-dimensional support structure and arranged in different directions to provide radiation diversity.

4. A three-dimensional implantable MIMO antenna for biological telemetry applications according to claim 1, characterized in that: Each antenna element is arranged to rotate relative to each other on the three-dimensional support structure. The arrangement of the feed ports, short-circuit pins and slotted structures between each antenna element allows the current polarity between adjacent antenna elements to be naturally reversed, thereby achieving self-decoupling and effectively reducing mutual coupling without the need for additional decoupling structures or increased element spacing.

5. A three-dimensional implantable MIMO antenna for bio-telemetry applications according to claim 1, characterized in that: Each antenna element also includes a cover layer disposed above each radiating patch, the dielectric constant of which is the same as that of the dielectric substrate.

6. A three-dimensional implantable MIMO antenna for bio-telemetry applications according to claim 1, characterized in that: Both the dielectric substrate and the capping layer are made of high dielectric constant materials to achieve antenna miniaturization while maintaining radiation efficiency.

7. An implantable biomedical device, characterized in that: It includes a three-dimensional multiple-input multiple-output antenna assembly, which is integrated into a device structure including electronic circuits, sensors and power supply, for the purpose of achieving reliable wireless communication and power transfer.

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