Bio-Matched Antenna Permittivity Structure for Tissue Interface Loss
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Solution Overview
Problem
Existing 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 medical 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 permittivity of biological tissues over a wide bandwidth, achieving high gain and minimizing transmission loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional wearable antennas are used, then the device can be worn on the body, but transmission loss is high due to mismatch at the biological tissue and antenna interface
Solution Approach 1:
The patent introduces an engineered periodic dielectric structure as an intermediary layer between the antenna and biological tissue. This intermediate structure has permittivity properties that bridge the gap between conventional antenna materials and biological tissue, reducing the impedance mismatch and minimizing reflection losses at the interface.
Solution Approach 2:
The patent modifies the permittivity parameter of the antenna system by incorporating an engineered periodic dielectric structure with specific permittivity values. This parameter change allows the antenna to better match the electromagnetic properties of biological tissue across a wide frequency bandwidth, thereby reducing transmission loss.
2Loss of energy
If conventional wearable antennas are used, then the antenna structure is simple, but transmission loss increases due to frequency-dependent tissue properties
Solution Approach 1:
The patent employs an engineered periodic dielectric structure composed of multiple materials with different permittivity properties arranged in a periodic pattern. This composite structure enables the antenna to maintain consistent performance across frequency-dependent biological tissues by providing a tailored effective permittivity that compensates for tissue property variations.
Solution Approach 2:
The engineered dielectric structure is divided into periodic unit cells with specific geometric patterns. This segmentation allows the structure to achieve an effective permittivity that is intermediate between the constituent materials, providing better impedance matching to biological tissue while maintaining a manageable structural complexity.
3Adaptability or versatility
If wide bandwidth is achieved through conventional means, then frequency coverage is improved, but transmission loss increases due to inherent material loss of biological tissues
Solution Approach 1:
The patent achieves wide bandwidth with reduced loss by carefully selecting and tuning the permittivity parameters of the engineered periodic dielectric structure. The structure's effective permittivity is designed to track the frequency-dependent permittivity of biological tissue across a wide frequency range, maintaining impedance matching and minimizing losses throughout the bandwidth.
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 a remarkable 14.5 dB lower transmission loss for subcutaneous implants and 10.8 dB lower for deep-tissue implants compared to state-of-the-art antennas, while maintaining a wide bandwidth and high gain, thus enhancing biomedical telemetry and radiometry capabilities.
Implementation Method 1
an engineered periodic dielectric structure composed of plastic and water to match the permittivity of biological tissues over a wide bandwidth
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.