DESIGN OF RF-BASED MULTI-RESONANCE SENSOR USING MULTIPOLE EXPANSION AND OPTIMIZATION IN IN-VIVO ENVIRONMENT

Department of Electrical EngineeringIn this paper, a multi-Resonance sensor using multipole expansion is proposed for microwave frequency region. To increase Q factor required for more sensitive and accurate detection, sensor design destructed electric dipole to minimize radiation resistance, and magnetic dipole was utilized as the main moment. A folded loop shape was proposed to fabricate this, it was deformed into a shape that could operate based on FR4 substrate, and optimization was performed to operate in a body environment having a high dielectric constant. Glucose concentrations were continuously measured through resonant frequency of reflection coefficient in water/rat environments similar to those in vivo, comparing the blood glucose concentration with the tendency of resonant frequency transition in rat. It was verified that the resonance frequency changed similarly from 2.34 GHz to 2.26 GHz while blood sugar changed from 500 mg/dL to 250 mg/dL.ope

A Microwave Ring-Resonator Sensor for Non-Invasive Assessment of Meat Aging

The assessment of moisture loss from meat during the aging period is a critical issue for the meat industry. In this article, a non-invasive microwave ring-resonator sensor is presented to evaluate the moisture content, or more precisely water holding capacity (WHC) of broiler meat over a four-week period. The developed sensor has shown significant changes in its resonance frequency and return loss due to reduction in WHC in the studied duration. The obtained results are also confirmed by physical measurements. Further, these results are evaluated using the Fricke model, which provides a good fit for electric circuit components in biological tissue. Significant changes were observed in membrane integrity, where the corresponding capacitance decreases 30% in the early aging (0D-7D) period. Similarly, the losses associated with intracellular and extracellular fluids exhibit changed up to 42% and 53%, respectively. Ultimately, empirical polynomial models are developed to predict the electrical component values for a better understanding of aging effects. The measured and calculated values are found to be in good agreement