An Ex Vivo Study of Wireless Linkage Distance between Implantable LC Resonance Sensor and External Readout Coil

Area of Science:

• Biomedical Engineering
• Implantable Sensors
• Wireless Communication

Background:

• Wireless monitoring of physiological parameters is crucial for healthcare.
• Implantable sensor performance is affected by distance and intervening media.
• Existing wireless sensor limitations necessitate improved range and reliability.

Purpose of the Study:

• To investigate the wireless linkage of an ex vivo implantable inductor-capacitor (LC) sensor.
• To evaluate the impact of biological tissues on sensor-reader distance.
• To explore methods for enhancing the remote readout range of implantable sensors.

Main Methods:

• Designed and fabricated a cost-effective LC resonance tank circuit implantable sensor.
• Utilized porcine and ovine tissues (skin, muscle, fat) to simulate biological environments.
• Measured the reflection coefficient (S11) to benchmark wireless linkage.
• Investigated the effect of a repeater coil on signal strength and readout distance.

Main Results:

• Achieved a readable wireless linkage up to 2.5 cm through layered biological tissues.
• The repeater coil increased the reflection coefficient signal magnitude by 3-3.5 times.
• Enhanced signal-to-noise ratio was observed with the repeater coil.

Conclusions:

• The developed LC sensor shows promise for ex vivo wireless monitoring.
• Biological media significantly influence wireless sensor performance.
• A repeater coil effectively extends the sensing range for implantable medical devices.