Bio-Matched Antenna Structure for Tissue Permittivity Matching
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Solution Overview
Problem
Current wearable antennas face challenges such as mismatch at the biological tissue and antenna interface, environmental and inter-subject variability, frequency-dependent tissue properties, and inherent material loss of biological tissues, which affect their performance in radiometry and telemetry applications.
Innovation Solution
The development of a bio-matched antenna (BMA) that utilizes an engineered periodic dielectric structure composed of plastic and water to match the frequency-dependent permittivity of biological tissues, providing high gain and wide bandwidth, and is designed to operate over a range of frequencies with reduced transmission loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional wearable antennas are used, then device simplicity is maintained, but transmission loss is high due to mismatch at the biological tissue and antenna interface
Solution Approach 1:
The patent applies composite materials by combining dielectric material with periodic metallic structures to create an effective medium that mimics biological tissue permittivity. This composite structure enables impedance matching between the antenna and biological tissue, significantly reducing transmission loss while maintaining a manageable device complexity through systematic design approaches.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the periodicity, geometry, and material properties of the metallic structures within the dielectric to achieve frequency-dependent permittivity matching. By varying these parameters, the antenna can be optimized for different frequency ranges while maintaining low transmission loss across the operating band.
2Reliability
If conventional antennas are used, then manufacturing simplicity is maintained, but performance varies due to environmental and inter-subject variability
Solution Approach 1:
The patent employs parameter changes to create a tunable antenna system where the periodic metallic structures can be adjusted to match different tissue types and environmental conditions. This allows the antenna to maintain consistent performance across varying subjects and environments while using standardized manufacturing processes for the modular periodic structures.
Solution Approach 2:
The patent achieves universality by designing a periodic structure that can be configured for different frequency ranges and tissue types. The same basic antenna architecture with periodic metallic elements can be adapted to various applications (radiometry, telemetry, imaging) and different biological tissues, improving reliability without requiring completely different designs for each case.
3Adaptability or versatility
If simple antenna designs are used, then device complexity is low, but bandwidth is limited and gain is reduced
Solution Approach 1:
The patent uses composite materials with frequency-dependent effective permittivity to achieve wide bandwidth operation. The periodic metallic structures within the dielectric create resonant effects that broaden the operating frequency range, enabling the antenna to maintain high gain and adaptability across multiple frequency bands while using a systematic composite structure.
Solution Approach 2:
The patent applies dynamics by creating an antenna structure where the effective electromagnetic properties change with frequency. The periodic metallic structures exhibit frequency-dependent behavior that enables the antenna to adapt its impedance and radiation characteristics across a wide bandwidth, maintaining performance without requiring multiple separate antenna elements.
4Measurement precision
If antennas operate at higher frequencies for better resolution, then measurement precision improves, but transmission loss increases due to frequency-dependent tissue properties
Solution Approach 1:
The patent uses parameter changes to match the frequency-dependent permittivity of biological tissues at higher operating frequencies. By adjusting the periodicity and geometry of the metallic structures, the antenna achieves impedance matching that compensates for increased tissue losses at higher frequencies, enabling improved measurement precision without prohibitive transmission loss.
Solution Approach 2:
The patent employs composite materials with tailored frequency-dependent properties that specifically address higher frequency operation. The periodic metallic structures create effective medium properties that reduce the impact of frequency-dependent tissue attenuation, allowing the antenna to operate at higher frequencies for better imaging resolution while maintaining acceptable transmission efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The BMA achieves significant reductions in transmission loss, offering improved communication efficiency for both subcutaneous and deep-tissue implants, with performance enhancements of up to 14.5 dB lower loss compared to state-of-the-art antennas, while maintaining robustness against rotational and positional misalignments.
Implementation Method 1
an engineered periodic dielectric structure composed of plastic and water to match the frequency-dependent permittivity of biological tissues
Implementation Method 2
The first antenna element is configured to receive an oscillating electric current and to radiate an oscillating electromagnetic field over a predetermined range of frequencies
Data Source
AI summary
An on-body antenna is provided that overcomes mismatch loss problems associated with current on-body antennas and is capable of operating over a wide range of frequencies with low transmission loss. At least a first antenna element of the on-body antenna is configured to receive an oscillating electric current and to radiate an oscillating electromagnetic field over a predetermined range of frequencies. The first antenna element is made of non-electrically-conductive material having a first relative permittivity. At least a second material having a second relative permittivity can be disposed on or in the first antenna element. Disposing the second material provides the first antenna element with an effective permittivity that can be closely matched to a frequency-dependent permittivity of biological tissue of a subject. The first non-electrically-conductive material and the second material can be preselected to have relative permittivities that allow anisotropy to be achieved.