Textile UWB 5G Antenna for Human Blood Clot Measurement

At a Glance

Metadata	Details
Publication Date	2022-09-29
Journal	Intelligent Automation & Soft Computing
Authors	K. Sugapriya, S. Omkumar
Institutions	Sri Chandrasekharendra Saraswathi Viswa Mahavidyalaya
Citations	5
Analysis	Full AI Review Included

Technical Documentation & Analysis: Diamond Substrates for High-Frequency UWB 5G Sensing

Executive Summary

This research details the design and performance of a textile-based Ultra Wide Band (UWB) 5G antenna sensor for continuous Prothrombin Time (PT) measurement in blood plasma. The findings highlight the critical role of low-loss dielectric substrates in achieving high-performance wearable medical sensors.

Core Application: Continuous, non-invasive Prothrombin Time (PT) measurement using a passive UWB 5G antenna sensor integrated into a wearable device.
Frequency Performance: The antenna operates in the UWB range (3.1 to 10.6 GHz) and exhibits wideband resonance up to 29 GHz, demonstrating suitability for high-speed 5G communication systems.
Material Limitation: The design relies on a low-cost, low-permittivity textile (jean’s substrate, ε_r = 1.7, loss tangent = 0.025), which inherently limits efficiency and Q-factor compared to advanced dielectric materials.
Key Achievement: Achieved excellent impedance matching (VSWR as low as 1.04) and high bandwidth (2-14 GHz) by optimizing the copper patch thickness (0.6 mm).
Safety Compliance: The proposed wearable design maintains a Specific Absorption Rate (SAR) below 2 W, meeting safety standards for human body proximity.
6CCVD Value Proposition: Diamond substrates offer orders of magnitude improvement in loss tangent (tan(δ) < 0.0001) and superior thermal management, enabling higher efficiency, greater power handling, and enhanced sensor reliability compared to the textile substrate used.

Technical Specifications

The following hard data points were extracted from the simulation and fabrication results of the proposed UWB 5G antenna sensor:

Parameter	Value	Unit	Context
UWB Operating Range	3.1 to 10.6	GHz	Standard UWB band
Fabricated Resonance Frequency Range (0.6 mm patch)	10 to 29	GHz	S₁₁ < -10 dB
Maximum Measured Bandwidth (0.6 mm patch)	2 to 14	GHz	Achieved with optimized patch thickness
Minimum Measured S₁₁ (Reflection Coefficient)	-48.46	dB	Achieved at 20.5 GHz
Minimum Measured VSWR	1.04	N/A	Voltage Standing Wave Ratio (0.6 mm patch)
Substrate Material Used	Jean’s Fabric	N/A	Textile substrate for wearable application
Substrate Dielectric Constant (ε_r)	1.7	N/A	Low permittivity
Substrate Loss Tangent (tan(δ))	0.025	N/A	Used for design
Total Antenna Dimensions	60 x 60 x 1.6	mm	Length x Width x Thickness
Maximum Specific Absorption Rate (SAR)	< 2	W	Measured on human phantom model
Blood Clotting Measurement Range (Voltage)	0.66 to 0.87	mV	Electromagnetic emitted voltage

Key Methodologies

The UWB 5G antenna sensor was developed and tested using the following steps, focusing on material selection, design optimization, and validation:

Antenna Design: A passive UWB microstrip patch antenna was designed, featuring a circular patch with a diamond-shaped slot, optimized for operation in the 3.1 to 10.6 GHz range.
Substrate Selection: Jean’s textile material was selected as the substrate (ε_r = 1.7, thickness 1 mm) to achieve wearable characteristics and low dielectric loss (tan(δ) = 0.025).
Simulation and Optimization: The design was simulated using High-Frequency Structural Simulator (HFSS) software, varying the copper patch conductivity thickness (0.6 mm and 1.06 mm) to optimize bandwidth and sensing characteristics.
Impedance Matching: A microstrip feed line and a partial ground plane were implemented to ensure good impedance matching and improved input excitation.
PT Measurement Protocol: Prothrombin Time (PT) was measured by mounting the UWB antenna onto a BD Vacutainer test tube containing blood plasma separated using Ethylene Di-amine Tetra Acetic Acid (EDTA) solution.
Wearable Analysis: Performance in a Wireless Body Area Network (WBAN) context was simulated using a four-layer human phantom model (Air, Skin, Fat, Muscle) to verify the Specific Absorption Rate (SAR) was below the acceptable limit.
Fabrication and Validation: A prototype was fabricated and measured using a Vector Network Analyzer (VNA) in an anechoic chamber to confirm simulated reflection coefficient (S₁₁) and radiation patterns.

6CCVD Solutions & Capabilities

The research demonstrates the feasibility of high-frequency sensing in medical applications, but the reliance on high-loss textile substrates (tan(δ) = 0.025) limits ultimate performance and power efficiency. 6CCVD’s MPCVD diamond materials offer a direct, high-performance upgrade path for replicating and extending this research into commercial-grade, high-reliability medical devices.

Applicable Materials

Research Requirement	6CCVD Material Recommendation	Technical Advantage
Ultra-Low Loss Dielectric Substrate	Optical Grade Polycrystalline Diamond (PCD) or Single Crystal Diamond (SCD)	Diamond exhibits a loss tangent (tan(δ)) typically < 0.0001, which is 250 times lower than the jean’s substrate (0.025). This drastically reduces signal attenuation, maximizing efficiency and Q-factor at 5G/UWB frequencies (up to 29 GHz).
Miniaturization for WBAN	Single Crystal Diamond (SCD)	SCD has a higher relative permittivity (ε_r ≈ 5.7) than the textile (ε_r = 1.7). This higher permittivity enables significant miniaturization of the antenna patch while maintaining resonant frequency, crucial for compact, high-density wearable sensors.
High Thermal Conductivity	SCD or High-Purity PCD	Diamond offers the highest thermal conductivity of any material, ensuring efficient heat dissipation for active 5G components or high-power sensing applications, improving device longevity and reliability.
Boron Doping for Active Sensing	Boron-Doped Diamond (BDD)	For future integration of active sensing elements or micro-electrodes (e.g., electrochemical sensing alongside RF), 6CCVD offers BDD films, providing a stable, conductive, and biocompatible platform.

Customization Potential

6CCVD is uniquely positioned to supply the advanced material components necessary to transition this UWB sensor technology from a textile prototype to a robust, high-performance medical device:

Custom Dimensions and Thickness: While the paper used a 60 x 60 mm patch, 6CCVD can supply PCD wafers up to 125 mm in diameter and control the thickness of SCD/PCD layers precisely from 0.1 µm up to 500 µm, allowing engineers to fine-tune resonant frequencies and bandwidth.
Precision Metalization: The antenna relies on copper patch optimization. 6CCVD offers in-house, high-precision metalization services, including Ti/Pt/Au, W, or Cu layers, ensuring excellent adhesion and optimal conductivity for the microstrip feed lines and radiating elements.
Surface Finish: For integration with sensitive biological samples or high-frequency signal integrity, 6CCVD provides ultra-smooth polishing (Ra < 1 nm for SCD and Ra < 5 nm for inch-size PCD), minimizing surface scattering losses.

Engineering Support

6CCVD’s in-house PhD team specializes in applying diamond materials to extreme environments, including high-frequency electronics and biomedical sensing. We can assist researchers and engineers in selecting the optimal diamond grade (SCD vs. PCD) and doping level (BDD) required to maximize efficiency, minimize loss, and achieve superior performance in similar WBAN, 5G communication, and high-frequency medical sensing projects.

Call to Action: For custom specifications or material consultation regarding high-performance dielectric substrates for 5G/UWB applications, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

The antenna plays an essential role in the medical industry. The short-range 5th Generation (5G) communication can be used for seamless transmission, reception, patient monitoring, sensing and measuring various processes at high speeds. A passive Ultra Wide Band (UWB) antenna, used as a sensor in the measurement of Prothrombin Time (PT) i.e., blood clot is being proposed. The investigated micro-strip patch UWB antenna operating in the frequency range of 3.1 to 10.6 GHz consists of a circular patch with a diamond-shaped slot made of jeans substrate material with good sensing properties is accomplished by adjusting the copper thickness of the patch. Due to the turbidity in blood plasma, PT measurement is the repetitive approach to get accurate value. In order to solve this issue, an antenna is designed, fabricated and analysed to obtain the accurate PT measurements from blood plasma. The blood clotting is observed by electromagnetic emitted voltage converted into the frequency range of 5 to 10 GHz and voltage range of 0.66 to 0.87 mV. The circular UWB antenna is constructed employing jean’s substrate with a partial ground plane to improve the S-parameter, gain, bandwidth and performance characteristics. The proposed antenna with Specific Absorption Rate (SAR) value within the acceptable range can be used as a wearable device in the human body, leveraging 5G technology. This antenna is well suited for various other applications like wireless sensors, wearable devices and short-range communication applications.

Tech Support

Original Source

DOI: https://doi.org/10.32604/iasc.2023.032163

References

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2018 - Performance study of a fractal UWB MIMO antenna for on-body WBAN applications [Crossref]
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2020 - Providing connectivity to implanted electronics devices: experimental results on optical communications over biological tissues with comparisons against ultra-wideband antenna
2020 - A miniaturized printed UWB antenna with sextuple stop bands based on U-shaped slot resonators and split [Crossref]