Abstract:
Backscatter radio has been widely used in remote and wearable sensing for body motion and vital signs. When a moving or shape-changing dielectric is placed in the near-fi...Show MoreMetadata
Abstract:
Backscatter radio has been widely used in remote and wearable sensing for body motion and vital signs. When a moving or shape-changing dielectric is placed in the near-field region of a pair of transmitter (Tx) and receiver (Rx) antennas, the Tx signal propagating to the dielectric will be backscattered and modulated by the motion as a time-varying complex phasor signal at the Rx. In this article, we proposed a semianalytical model based on the electromagnetic field perturbation of the electric dipole (ED) mode of a dielectric sphere. Our proposed model analyzed how the changes in object shape, antenna pair position, and carrier frequency affect the backscattered field. To validate our proposed field model, we designed a torso phantom and performed experiments with an antenna pair at eight different front positions as well as four different sub-1-GHz carrier frequencies. Our model-generated signals had an average of 0.98 cross-correlations with the experimental recording from the six central positions and four frequencies. Furthermore, we added scaling factors to represent the antenna performance for magnitude and phase matching. After performing a least-squares fitting, our scaling model achieved similar fitting errors as the ground-truth measurement variations with average adjusted R -squared scores of 0.86 and 0.89 for different sensing positions and carrier frequencies.
Published in: IEEE Transactions on Microwave Theory and Techniques ( Volume: 72, Issue: 2, February 2024)
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- IEEE Keywords
- Index Terms
- Scaling Factor ,
- Shape Changes ,
- Wearable ,
- Carrier Frequency ,
- Electric Dipole ,
- Phase Matching ,
- Receiver Antenna ,
- Transmitter Antenna ,
- Antenna Pair ,
- Rx Antenna ,
- Semi-analytical Model ,
- Root Mean Square Error ,
- Field Strength ,
- Electromagnetic Wave ,
- Field Changes ,
- Differential Signal ,
- Incident Wave ,
- Radio Frequency Identification ,
- Complex Domain ,
- Magnitude Of Signal ,
- Tx Antenna ,
- Dielectric Changes ,
- Center Of The Sphere ,
- Normalized Cross-correlation ,
- Constant Field ,
- Antenna Characteristics ,
- Frequency Of Electromagnetic Wave ,
- Multipath Interference ,
- Relative Dielectric Constant ,
- Fitting Accuracy
- Author Keywords
Keywords assist with retrieval of results and provide a means to discovering other relevant content. Learn more.
- IEEE Keywords
- Index Terms
- Scaling Factor ,
- Shape Changes ,
- Wearable ,
- Carrier Frequency ,
- Electric Dipole ,
- Phase Matching ,
- Receiver Antenna ,
- Transmitter Antenna ,
- Antenna Pair ,
- Rx Antenna ,
- Semi-analytical Model ,
- Root Mean Square Error ,
- Field Strength ,
- Electromagnetic Wave ,
- Field Changes ,
- Differential Signal ,
- Incident Wave ,
- Radio Frequency Identification ,
- Complex Domain ,
- Magnitude Of Signal ,
- Tx Antenna ,
- Dielectric Changes ,
- Center Of The Sphere ,
- Normalized Cross-correlation ,
- Constant Field ,
- Antenna Characteristics ,
- Frequency Of Electromagnetic Wave ,
- Multipath Interference ,
- Relative Dielectric Constant ,
- Fitting Accuracy
- Author Keywords