Microfluidic Sensor Based On Metamaterials

Metamaterials is a kind of new artificial material, which has special electromagnetic properties, such as negative equivalent permittivity and negative equivalent permeability which are not possessed by ordinary natural materials, have caused widely concerns. Now researching for a wide variety of devices which based on metamaterials is endless, such as filters, absorber, isolators, antenna, wireless charging system and modulators. The microfluidic sensor based on the metamaterials has received more and more attention in the field of biological engineering and medicine because of its inherent advantages: the simple structure, easy to integrate, timely detection, no mark detection, no change of the inherent chemical physical properties of the solution, etc.First of all, this thesis makes a research and basic theoretical deduction of the metamaterials, focusing on the equivalent negative permittivity and negative permeability. Then a number of special effects caused by this characteristic are demonstrated, and the equivalent constitutive parameters are extracted by using the S parameter method.Secondly, the metamaterials element- split ring resonator which meet the special requirements of microfluidic sensor is used to design a preliminary microfluidic sensor, and the material and size are optimized through simulation analysis. According to the equivalent circuit analysis and simulation analysis, the structure is continuously improved to optimize its performance, then put forward microfluidic sensor based on double split ring resonator, microfluidic sensor based on rectangular resonant ring and microfluidic sensor based on symmetric resonant ring. The relationship between the resonant frequency and the peak attenuation of the sensor and the relative dielectric constant of the sample solution was obtained by fitting the curve. The improved sensor has high sensitivity(up to 18.99MHz/RIU2). Its working frequency band(2GHz-5GHz) is easy to detect. And it can use the resonance frequency and the peak attenuation of the transmission curve as the sensing index at the same time.Finally, taking into account the practicality, three kinds of microfluidic sensors based on the complementary resonant ring which excited by microstrip line are designed, and the relationship between the resonance frequency and the peak attenuation of the sensor and the relative dielectric constant of the sample solution is obtained. The microfluidic sensor based on the complementary symmetric resonant ring which has the best comprehensive performance is chosen to make the material object. And using the Agilent network analyzer proper did 4 sets of independent test. Compared with the simulation results, the error causes are analyzed.In summary, the design of the microfluidic sensor based on metamaterials have good performance. And it has certain guidance and reference significance to the research of the microfluidic sensor based on metamaterials.