A RF Sensor to Detect Lipohypertrophy of Insulin Injection

This paper proposes a design of RF sensor to detect lipohypertrophy of insulin injection. The design uses spiral inductors, which enable the sensor to have multiple resonance frequency and sensitivity to near-field effects, thereby detecting lipohypertrophy. This article validates the sensor through pork and phantom testing, providing a new non-invasive method for detecting lipohypertrophy. In pork testing, lipohypertrophy resulted in a decrease of approximately 5.5 dB in the magnitude of the S11 resonant frequency at 3.95 GHz and 5.45 GHz, and a increase of approximately 4 dB in the magnitude of the peak magnitude of the S21 at 3.25 GHz and 3.95 GHz. In phantom testing, lipohypertrophy resulted in a decrease of 2.2-2.7 dB in the magnitude of the S11 resonant frequency at 5.45 GHz and 6 GHz with 20 MHz shift, and a increase of approximately 1 dB in the magnitude of the peak magnitude of the S21 at 3.17 GHz and 3.9 GHz with 100 MHz shift. Experimental studies show that the presence of lipohypertrophy in tissues can be measured by analyzing changes of S parameters.