A Defected Ground Comb Shape Microwave Sensor for Non Invasive Measurement of Blood Glucose

This paper presents a miniaturized defected ground comb shape microwave sensor to detect blood glucose concentration in diabatic patients non-invasively. Proposed sensor works in the frequency range of 4.75-5.5 GHz at operating frequency of 5.25 GHz. The impedance bandwidth of 750 MHz (14.29
^%
) is found with reflection coefficient
$\vert \mathrm{S}11 \vert$
of-45 dB. The proposed sensor shows compact volume of
$\mathbf{20}\times \mathbf{20}\times \mathbf{0.8}\ \mathbf{mm}$
3 fabricated on FR4 substrate. The glucose detection is measured in terms of frequency shift and varying
$\mathrm{S}_{11}$
with respect to relative permittivity of human blood cells. The experimental validation is performed by interacting proposed sensor with human thumb. Observed frequency shift and corresponding sensitivity of sensor are 1.75 GHz and
$6\ \text{MHz}/\varepsilon\mathrm{r}$
respectively. The observed results of proposed sensor satisfied that it is useful for sensing of non-invasive blood glucose level in diabetic patients.