Differential Microstrip Sensor for Complex Permittivity Characterization of Organic Fluid Mixtures

Abstract

A microstrip highly sensitive differential sensor for complex permittivity characterization of urine samples was designed, fabricated and tested. The sensing area contains two pairs of open-stub resonators, and the working frequency of the unloaded sensor is 1.25 GHz. The sensor is easily implemented on an affordable substrate FR-4 Epoxy with a thickness of 1.6 mm. A Teflon beaker is mounted on the sensor without affecting the measurements. Numerically, liquid mixtures of water and urine at different percentages were introduced to the proposed sensor to evaluate the frequency variation. The percentage of water content in the mixture varied from 0% (100% urine) to 100% (0% urine) with a step of 3.226%, thus giving 32 data groups of the simulated results. Experimentally, the mixtures of: 0% urine (100% water), 20% urine (80% water), 33% urine (66% water), 50% urine (50% water), 66% urine (33% water), and 100% urine (0% water) were considered for validation. The complex permittivity of the considered samples was evaluated using a nonlinear least square curve fitting in MATLAB in order to realize a sensing sensitivity of about 3%.

Non‐invasive microwave blood glucose monitoring based on the diffusion limited aggregation earlobe model

“…In this study, there is a region in the 8.0–10.0 GHz frequency range. In this region, the variation in S 11 parameters shows a good regularity with variation in blood glucose concentration, and the regularity is consistent with the conclusions in Reference 13. Comparing Figure 6A and B it can be found that the unwrapped phase of S 11 is more sensitive to changes in blood glucose concentration.…”

“…The work in Reference 12 supports the feasibility of the method based on biological impedance difference in assessing blood glucose level through in vivo and in vitro experiments. The method of using microwave sensors to detect the mixture concentration is proposed in References 13‐18, which can also be used to detect blood glucose level 19 . Non‐invasive blood glucose monitoring technology using ultra‐wideband microwave has been proposed in Reference 20.…”

Double-negative metamaterial square enclosed Q.S.S.R For microwave sensing application in S-band with high sensitivity and Q-factor

“…2 c. The prototype's inductance and capacitance are modelled using lumped components. The Q factor is of paramount importance when it comes to broadband hybrid microcircuits; the most efficient solution is to use lumped components 46 . The proposed design addresses these issues through use of a comprehensive mathematical model.…”

Low-cost microstrip sensor based on coupled step line (CSL) resonator for blood plasma glucose determination

“…Microstrip sensor structures have also found applications in the medical and pharmaceutical fields . UWB microstrip antennas for cancer detection [17][18][19], complementary split ring resonator (CSRR) for urine testing [20,21], a narrowband sensor for the measurement of BGL and hemoglobin [22][23][24][25][26][27][28][29][30][31][32][33][34][35], and * Author to whom any correspondence should be addressed. microwave resonators for recognizing characterization of biological tissues [36,37] are among the important applications of microstrip sensors in medical and biomedical sectors.…”