Design of Microwave Electromagnetic Sensor for Liquid Characterization

The design, fabrication, and testing of a highly sensitive GHz sensor for real-time measurement of engine oil quality are presented in this paper. The proposed microwave sensor is constructed on symmetric square slots structures, to improve the performance of the sensor. By using the resonant perturbation theory, the change in the max E field of test samples, produce the frequency shift. The footprint of the designed sensor is (0.5523λeff × 0.0920λeff) where λeff is the effective wavelength value calculated at the operating frequency of 5.52GHz. The oil sample adulteration analysis is done by immersion of a dielectric probe up to a reference level of 20 mm. Thus, the dielectric behavior of the sensor is estimated with an average sensitivity of 1.7. The performance of the microwave sensor is evaluated by submerging it in different engine oil samples, thereby resulting in frequency shifts from 5.53 to lower values. The result obtained from it indicated that the sensor has a quality factor of 54.55 and a FoM of 19.17. Thus, the proposed GHz sensor due to its good sensitivity, FoM, and quality factor is the eminent solution for the automobile industry.