Improve planar multiple split-ring sensor for microwave detection applications

Abstract In this paper, a sub-wavelength resonance sensor is proposed to microwave detection applications. A meta-material element—multiple split ring resonators (MSRR) is used to improve the sensitivity of the sensor. Therefore, the sensor is based on micro-strip technology and consists of a micro-strip and a MSRR. It is observed that the strongest electric field of the sensor can achieve to 105 V/m. So the sensor is very sensitive to capture changes of dielectric signals. Some experiments were carried out using the fabricated sensor, and a network analyzer (AV3609D) with liquids under test (LUT) inserted the sensor. Furthermore, primary finite element analysis and test results are used to compare the MSRR-based and a general complementary split ring resonator (CSRR)-based sensing sensor, demonstrating sensitivity improvement of up to 1.3 times. The proposed MSRR-based sensor has stronger coupling between the micro-strips of the open-loops of the MSRRs, which can reduce the reflection and dimension of the sensor. Therefore, this sensor is well suited for low-cost, real-time, and CMOS compatible sensing technologies.