关键词: 微波传感器, 酵母菌检测, 超材料, 生物传感器

Abstract: In the field of food processing, monitoring the yeast content is extremely important for the yield and safety of the products, and the commonly used traditional methods such as plate counting method have the problems of complicated operation, long detection time, and large equipment size. Therefore, it is necessary to develop a new type of yeast sensor to meet the complex needs in the food processing field. A microwave metamaterial biosensor that is simple to operate, non-contact, low-cost and miniaturized is proposed for the detection of yeast solutions in the concentration range of 5×10¹-5×10⁴ CFU/mL. The microwave sensor combines a metamaterial structure with a fork-finger capacitance structure to achieve miniaturization of the device, which further enhances the strength of the electric field on the sensor surface and improves the sensitivity of yeast detection. Two microwave parameters, resonant frequency and harmonic amplitude value, are used to characterize different concentrations of yeast solutions, and the amounts of change in resonant frequency and harmonic amplitude value during the detection process are 2.6 MHz and 0.03 dB, respectively, achieving the sensing of yeast solutions. This study provides a new solution for monitoring yeast concentration in the food processing field and broadens the application of microwave biosensing.

Key words: microwave sensor, yeast detection, metamaterial, biosensor