Diabetes mellitus is an uprising mortal disease, one case of metabolic disorder that is induced due to inadequate secretion of insulin, consequently elevating blood sugar levels in an uncontrolled manner. The failure of controlling glucose levels will lead to disastrous complications such as kidney disease, blindness, lower limbs amputation, stroke heart attack. Altogether, more than 415 million adults lived with the condition in 2015 and this figure is anticipated to rise to above 640 million or one in ten adults by 2040 1. In Singapore, diabetes is a grave health concern, with over 400,000 Singaporeans living with the disease. One in three Singaporeans has a lifetime risk of getting diabetes and the number of those with diabetes is projected to achieve one million by 2050 if current trends remain 2.
The prerequisite for proper diabetic management is to monitor blood glucose level at regular intervals to avoid serious life-changing complications due to diabetes mellitus. Most of the available devices used for blood glucose testing are painful as they are invasive in nature and hence are not suitable for monitoring of blood glucose continuously. Several methods have been introduced for non-invasive measurements, such as optical methods, magnetic induction, and microwave sensors. Extensive research is being carried out in this area; however, none of the developed non-invasive blood glucose monitors is commercially available to replace conventional invasive monitors due to several restrictions associated with each device.
The applied science of non-invasive blood glucose monitoring is desirable, as it does not take a blood sample to be elicited from the human physical structure. The approach adopted is based on the concept of variation of dielectric properties of blood (permittivity and conductivity) due to change in aqueous glucose concentration which will affect the near-field coupling and electromagnetic transmission. This will result in the change of input impedance of sensor and which in turn will affect its resonant frequency. This frequency and phase shift can be used to observe the change in blood’s permittivity and conductivity, which will be functional to estimate the concentration of glucose in the blood.
The research is to measure the blood glucose concentration by analyzing the perceived microwaves. Since the skin of ear lobule is very thin, we considered the earlobes as the region of interest. A pair of antennas is placed on earlobe portion in order to transmit the microwaves. The earlobe is modeled as a locally planar structure in many related studies3. The earlobe portion is simulated in CST software. The geometrical configuration shown in fig1 is the perceiving structure modeled in this study. The tissues and other biological matter are assumed as layered arrangements. This kind of alignment is used to check the practicality of the anticipated method.
The blood is modeled as a layer of 2 mm thickness which is covered on both sides by a fat layer of thickness 2 mm. The fat layer is covered by skin layer of thickness 2 mm on both sides. The overall dimensions of the model occupied a volume of 10 x 10 x 10 mm3.