Effect of Layout Shape on the Performance of OCSRR Microwave Sensor

Microwave sensors based on open complementary spilt ring resonator (OCSRR) structures have been widely studied and applied because of their small electrical size, they are also very sensitive to dielectric loading. The purpose of this paper is to study OCSRR microwave sensors based on different shapes (square, round and trapezoid), using resonant frequency f
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as well as return loss Sll to characterize the dielectric properties of ethanol solutions when the other variables (overall area, channel length and channel gap, etc.) are the same as well as the resonant frequency. From the results, the sensitivity of the square structure of the OCSRR microwave sensor is the highest, 0.16 MHz/% and 0.084 dB/%, respectively, whether the sensitivity is calculated based on the resonant frequency or the change in return loss amplitude. This is because, on the one hand, the square structure of the OCSRR microwave sensor accumulates more electric field energy than the round and trapezoid; on the other hand, the quality factor of the square structure of the OCSRR microwave sensor is higher than those of the round and trapezoid.