Cylindrical Cavity Sensor for Distinction of Various Driveability Index Gasoline with Temperature Robustness

Abstract

In this paper, a cylindrical cavity sensor based on microwave resonant theory is proposed to distinguish between various driveability index gasolines under temperature variations. The working principle of the proposed sensor is based on the fact that the change in permittivity of gasoline samples inside cavity sensor will also cause a change in resonant frequency. The proposed sensor has good sensitivity in terms of resonant frequency separation, which enables it to capture the minute permittivity changes and distinguish different gasolines. By using a normal gasoline permittivity of 2.15 and changing sensor dimension parameters, the sensor was designed by high-frequency structure simulator (HFSS). The designed sensor has a resonant frequency of 7.119 GHz for the TM012 mode with a 19.2 mm radius, a 35 mm height, and one-port coupling probe of 8 mm height. The proposed cylindrical cavity sensor shows advantages of excellent resonant characteristics of small cavity size and small sample amount. To optimize and verify the parameters of the sensor, many experiments have been carried out using HFSS and a vector network analyzer (VNA). Consequently, the proposed sensor is proven to be robust to temperature changes in terms of resonant frequency separation. The minimum frequency separation to distinguish gasoline samples is found to be larger than 29 MHz with reflection coefficients under −11 dB for temperature changes from −35 °C to 0 °C. The consistency of experimental and theoretical results also are presented, which guarantees accuracy of the sensor for the distinction of gasoline.

Uniformity enhancement of a microwave surface-wave plasma by a field agitation

“…The numbers for the mode (m = 1, and n = 3) are determined from the operation frequency of a microwave generator source (2.458 GHz) and the diameter of the cylindrical cavity (395 mm). 10,12,15,16) Secondly, the method for re-distribution of the electric field inside the chamber is different to some degree; the phase difference between the two microwave inputs (f) was either fixed (fast rotation) or changed gradually (slow pulsation) in the previous studies, but in this work the f is controlled by toggling its value between 0°and 180°. By setting the f to be 180°, the field would have a distribution rotated by 90°anticlockwise compared to the f = 0°case.…”

Rectangular Cavity Sensor for Distinguishing Between Normal and High-Drivability-Index Gasolines

“…Similarly, Karuppuswami et al [19] proposed a rectangular cavity sensor fabricated by a 3D printer for liquid detection. Following the cavity design, a cylindrical cavity sensor for gasoline DI distinction was proposed by Chong et al [20].…”