Microwave Antenna Array for Osteoporosis Detection
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Solution Overview
Problem
Current microwave imaging techniques for bone health diagnostics are complex and lack clinical applicability due to poor spatial resolution, making them ineffective for osteoporosis detection, which requires tracking RF signal changes through bone tissue rather than reconstructing permittivity maps.
Innovation Solution
A simplified transmitter-receiver setup using a 2×1 patch antenna array with a 180-degree power splitter and RFID technology to measure RF signal propagation through the wrist, eliminating the need for custom beamforming networks and reducing complexity and cost, while focusing on tracking signal changes indicative of osteoporosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If standard microwave imaging setup is used to restore complete permittivity map, then comprehensive bone tissue information is obtained, but spatial resolution is poor and device complexity is high making it clinically inapplicable
Solution Approach 1:
The patent extracts only the essential information needed for osteoporosis detection (signal strength and reflection coefficient changes along the RF path through bone) rather than attempting to restore the complete permittivity map. This selective extraction of relevant information maintains diagnostic capability while eliminating the complexity and resolution limitations of full microwave imaging reconstruction
Solution Approach 2:
Instead of using complex microwave imaging to reconstruct permittivity maps and then extract bone density information, the patent inverts the approach by directly measuring RF signal transmission and reflection properties to obtain bone density estimates. This reversal simplifies the measurement system while maintaining the ability to detect osteoporosis
2Loss of information
If standard microwave imaging setup with beamforming network is used, then complete permittivity map can be restored, but device complexity and cost increase significantly
Solution Approach 1:
The patent removes the complex beamforming network and permittivity map reconstruction algorithms from the system, extracting only the essential RF transmission and reflection measurements needed for bone density assessment. This eliminates unnecessary complexity while preserving the core diagnostic function
Solution Approach 2:
The patent inverts the conventional microwave imaging approach by not attempting to restore the complete permittivity map through complex beamforming, but instead directly using RF signal transmission and reflection measurements to estimate bone density. This inversion dramatically simplifies the device architecture
3Device complexity
If single antenna is used for RF signal transmission, then device simplicity is maintained, but penetration depth and return signal are insufficient for effective osteoporosis detection
Solution Approach 1:
The patent segments the single antenna function into multiple antenna elements arranged in arrays (e.g., 4×4 element arrays). This segmentation allows for better signal penetration depth and stronger return signals through constructive interference and increased transmitted power, while maintaining relative system simplicity through the use of standard RFID components
Solution Approach 2:
The patent combines multiple antenna elements into coordinated arrays that work together to achieve improved penetration and signal return. By merging multiple simple antenna elements into a functional array system, the patent achieves enhanced performance without requiring a single complex antenna design
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
This approach allows for effective detection of osteoporosis by measuring RF signal strength and reflection coefficients, providing a clinically applicable method for bone density estimation with improved penetration and cost-effectiveness.
Implementation Method 1
measure a radio-frequency signal propagating through the wrist
Implementation Method 2
the decrease in the dielectric constant generates significantly different scattering and/or reflection of an RF signal passing through the bone
Implementation Method 3
at least two radiators driven out of phase via a 180 degree power splitter
Implementation Method 4
a modern RFID reader with an on-skin reader antenna and a number of on-skin passive RFID tags
Data Source
AI summary
The present invention relates to a microwave sensing device that uses antennas in the form of a 2×1 array with two radiators driven out of phase via a 180 degree power splitter for measuring a radio-frequency signal propagating through a mammalian specimen to obtain an integral estimate of bone density.