Research Of Resonant Structure Based Millimeter Wave Biosensor Technology

With the continuous development of biomedical technology,low-cost,portable and minimally invasive biosensors have become a current research hotspot,and millimeter-wave biosensors have attracted much attention due to their label-free,non-invasive and miniaturized advantages.Millimeter-wave biosensors based on resonant structure have high sensitivity and simple structure,and have potential in biofluid detection.Therefore,this thesis focuses on the design and application of millimeter-wave biosensors based on resonant structures,and the main work and contributions are as follows:1.A biosensor based on coupling line with via-hole first-tail coupling structure is proposed,and two biosensors with detection frequencies of 21～26 GHz and 32～38 GHz are fabricated based on gold-clad ceramic substrate process and microfluidic PDMS process,and after practical tests,the maximum frequency shifts are 200 MHz and 330 MHz respectively after passing into Hep G2 cell suspensions,the small volume detection of Hep G2 cell suspensions was achieved.2.With the design goal of distinguishing different liquids,a biosensor based on the structure of split coupling ring is proposed based on the parallel coupling line theory.The frequency offset of the transmission zero point in the simulation results shows that the biosensor can effectively detect purified water,blood and ethylene glycol;based on this,a millimeter wave biosensor based on the via-hole loaded split coupling ring structure is designed,and the detection sensitivity is enhanced by introducing via-hole in the split coupling ring structure.After simulation analysis,the biosensor features an increased number of detection markers and a larger amount of frequency bias,which improves detection sensitivity and enables detection of small volumes of purified water,blood and ethylene glycol.3.With the design goal of distinguishing different cells,a fifth-order inductive diaphragm waveguide structure and a modified inductive diaphragm waveguide structure are designed,and an experimental scheme based on hose and glass needle loaded with inductive diaphragm waveguide structure is proposed.In the frequency range of 45～50 GHz,the biosensor can effectively detect purified water,culture fluid,milk,cola,ethanol and acetone;effectively distinguish THP-1 human monocytic leukemia cells and Caco-2 human colon;it can also distinguish human non-small cell lung cancer cell A549 and human liver cancer cell Hep G2,and these measured results verified the feasibility of the experimental scheme based on the tube and glass needle loaded inductive diaphragm waveguide structure.