Metamaterial incorporated microstrip based sensor for dielectric material characterization

Abstract

Microwave sensors are widely utilized in many industries such as agriculture, the biomedical sector, and electronics because they offer a short reaction time, a wide sensing range, excellent precision, operated in a harsh environment, and have no temperature influence. However, conventional microwave sensor has limitation such as complex design, lack of sensitivity, larger dimension, high cost, and allowing one analyte at a time, etc. To overcome these shortcomings, a metamaterial incorporated microstrip based lightweight portable microwave sensor with enhanced sensitivity is introduced where split ring based metamaterial increases the compactness of design and the accumulation of the electromagnetic field on the surface. High frequency electromagnetic simulator CST microwave studio was utilized to observe the scattering properties. The developed sensor was fabricated and the test materials for characterization were placed on the proposed sensor, where the resonance frequency deviation for different MUT (Material under test) was observed with the vector network analyzer. In this research work, the current effort involves the design of a new metamaterial-based sensor that can be used to detect substances. In order to maximize the sensor resiliency and compactness of the sensor, two types of metamaterial incorporated microwave sensors were introduced. Firstly, a body centered metamaterial incorporated sensor was proposed which produced the resonance at 6.2 GHz with the dimension 20×22 mm2. Five types of metamaterial unit cells were analyzed for the sensing performance where nested meander line based metamaterial shows a greater concentration of electromagnetic field with the compactness of 4.14. Secondly, dual split rings enclosed microstrip based sensor with the dimension 20×20 mm2 produced dual resonance frequencies at 3.56 and 4.14 GHz with the compactness of 3.57. The proposed sensors can distinguish material properties on their distinct resonance frequency shift which shows a good linear correlation for low permittivity values with non-invasive label free detection which was near unity. Moreover, the compactness and simplicity of the design make it more compatible for ease of integration with other microwave devices.