## 4 Discussion and Conclusions  
In the article, a study of the near-field probe in the form of a folded dipole was carried out by means of numerical and field experiments. Two versions of the probe design were considered: bidirectional and unidirectional. The results of modeling a unidirectional probe showed that limiting radiation in one direction significantly increases the signal response when the glucose concentration changes. The sensitivity of the probe during simulation was 1.5-2.7 dB/(mmol/L). Real experimental studies based on the created probe showed a slightly lower sensitivity of 1 dB (mmol/L). However, even this value significantly exceeds the analogs. The resulting regression line allows to predict the concentration value when it changes. Also, in addition to the amplitude sensitivity, this probe allows to measure the concentration by the frequency shift of the resonance. The sensitivity was 4.34-5 MHz/(mmol/L). The use of frequency and amplitude sensitivity allows to accurately determine the glucose concentration values. In addition to the unidirectional probe, a bidirectional probe experiment was also performed. The obtained data are significantly less in amplitude. The sensitivity of the bidirectional probe was 0.136-0.5 dB/(mmol/L). This sensitivity is significantly lower than that of a unidirectional probe, but in comparison with some analogs, it is still higher in sensitivity. Thus, these studies have shown the fundamental possibility of measuring glucose concentration with this design of the near-field probe. The results obtained show that the use of a unidirectional probe of this design makes it possible to determine the level of glucose concentration with high accuracy. Discussion of the challenges in moving to in vivo use conditions. For in vivo use, it is necessary to minimize the size of the probe for ease of use on humans with subsequent research. Presumably, the probe will be located on a person's arm in the crook of the elbow area, where the venous vessel is located. It will be necessary to ensure a uniform tight fit of the sensor to the human body. This may require a transition to a flexible dielectric substrate. Regarding the presence of blood flow in the capillaries or vasculature and whether dynamic flow will introduce errors in measurements we can say that in the modeling and experiments carried out at this stage, the influence of the saline solution flow speed in the vessel on the reflection coefficient was not considered, since the probe measurements are carried out in 3.6 \(\upmu\)s per point and when considering 8008 points, the measurement time is 0.028 s. At a flow speed of 150 mm/s, it has no effect on the reflected signal. In capillary vessels, the flow speed is 1 mm/s, which, accordingly, will also not affect the values of the reflected signal. Thus, at this stage of the study, we can say that the dynamic flow will not introduce errors in measurements. In general, non-invasive measurements are very sensitive to various types of interference, and many factors can affect the recorded signal. In the article, the authors use except for glucose solutions, averaged literature data. Meanwhile, people are individual and have a wide variation in blood hemoglobin, hematocrit, degree of skin hydration, cholesterol, thickness of skin layers, vascular architectonics, etc., especially sick people. There are no reliable literature data on the scatter of these data (except for glucose levels) in patients with diabetes mellitus. Moreover, glucose is found not only in the blood, but also in the intercellular space, and in a different concentration. All these factors are individual for each person and changeable in time (in different time scales). For example, the amount of blood, fluid, and, consequently, glucose in the diagnostic volume (in probing) can vary greatly from vasoconstriction/dilation with changes in pressure, temperature, when the patient usesdiuretics, etc. All these factors must be considered when assessing measurement result.