Novel Design of SSPP based Metamaterial Inspired THz Biosensor

Abstract

A novel design methodology to realize the planar terahertz (THz) biosensor is presented in this work. The proposed biosensor comprises of the planar spoof surface plasmon polariton (SSPP) based transmission line integrated with the complementary split ring resonator (CSRR) etched on the back side of the line. The SSPP transmission line is realized using a newly proposed dumbbell-shaped metallic strip which actually provides better confinement of the field than the conventional microstrip line, and hence it results into improved sensitivity of the designed sensor. The CSRR structure is incorporated at an appropriate position beneath the SSPP transmission line in order to facilitate its proper electric coupling with the highly confined dumbbell cell of the SSPP transmission line. The proposed biosensor is designed and optimized using the 3D electromagnetic field simulator (CST-MWS) in terahertz frequency region to obtain the desired sensitivity. The dimensions of the proposed designed sensor at THz frequency are scaled up, and the fabricated prototype is experimental tested with biological test specimen in the microwave frequency region. For the microwave testing of biological liquids, the CSRR sensing region possessing higher electric field intensity is integrated with a PDMS channel in order to avoid the contamination of the test specimens using the proposed non-invasive biosensor. As the hypertension and diabetes are the two most common causes for various health problems, therefore in this work, the detection of various volume proportions of saline and glucose concentration inside the solution is carried out to identify the symptom of these two targeted diseases.