Microwave/Millimeter Wave Biosensors Based On The Spoof Surface Plasmon Polaritons

The microwave and millimeter-wave biosensor technology applied to detect the cancer in superficial tissues including breast cancer,skin cancer,and lymphoma has been widely studied by researchers.With the development of big data and mobile medical care,microwave and millimeter wave technology combined with bio-sensing technology has important value of application in cancer detection,disease monitoring and disease nursing.In particular,the development of lab-on-a-chip and implantable chips has a wider range of applications in disease detection,higher sensitivity,more practicality,and more cutting-edge.In this paper,around the purpose of malignant melanoma skin water content detection,the following work has been carried out in detail:(1)The dielectric properties of skin tissue with different moisture content in microwave and millimeter wave band were studied theoretically.By combining Bruggeman mixing equation and Eyring relaxation time model into Debye equation,the factor of water content and temperature has been fully considered into the relaxation time,static permittivity,and optical permittivity of the Debye equation.Comparing with the traditional method for calculating the dielectric properties of the human body,the revised Debye model are fully considered the influence of changed water content,body temperature,and the frequency of electromagnetic waves.(2)A new type of microwave biosensor that can be used to detect the melanoma and skin water content has been developed.The SPPs staggered grating microwave biosensor was designed and simulated based on the pseudo-surface plasmon polaritons.According to the S-parameters of the skin model with different water content volume fractions,the sensitivity standard of the designed SPPs staggered grid biosensor was defined.The simulation results show that the designed sensor is sensitive to water content of skin tissues which can be used to distinguish skin water content and effectively distinguish between normal and cancerous cells.Finally,the sensor was processed and tested,experimental results of the biosensor with/without normal human finger skin tissues and pure water have a good agreement with our simulation.The SPPs biosensor can benefit from distinguishing tumors from normal biological tissues and has potential applications for the areas of in-vivo measurement of the human stratum corneum water content with topical cosmetics,early diagnostics of superficial tumors such as malignant melanoma and lymphatic cancer,and also in the guiding tumors resection.(3)A new type of SPPs biosensor based on folded waveguide is designed and optimized.The simulation results show that the designed sensor has a better performance and can be more effective in detecting skin cancer tissue.