Specification Development for Millimeter-Wave Absorption-Based Non-Invasive Glucose System

A non-invasive glucose measurement system is designed based on millimeter-wave (MMW) absorption spectroscopy. The non-invasive glucose system is formed by a transmitter chip, a receiver chip, and two probes that are fabricated on the printed circuit board (PCB). These MMW building blocks operate at 28–30 GHz. One of the two probes is connected to the output of the transmitter while the other to the input of the receiver. During the operation, the transmitter delivers the 28–30 GHz signal to the human ear via the PCB probe. Part of the signal is absorbed by the human tissue while the rest of the signal passes through the earlobe to be received by the receiver via the other PCB probe. The MMW absorption is influenced by the glucose concentration of the human tissue, so the received power level is used as the glucose concentration indicator. The procedure of specification development for the system is presented. Firstly, the human tissue-mimicking phantoms with different glucose concentrations are fabricated to characterize the path loss contributed by the biological media including the PCB probes and the phantoms. Secondly, the transmitter output power is estimated. Then, the input range of the receiver can be estimated. Finally, the specifications such as the noise figure, gain, and linearity of the receiver building blocks are determined.