Modeling And Application Study Of Flexible Microstrip Antenna Sensor

Flexible microstrip antenna sensor has the advantages of simple structure,small size,light weight and simple manufacturing process.It is widely used in structural health detection,wearable communication system and human motion detection.In wearable applications,the flexible microstrip antenna sensor is directly worn on the surface of the human body.The design of the sensor not only needs to meet the matching conditions of resonant frequency and impedance,but also needs to have wearable comfort,that is,the sensor needs to be miniaturized.Therefore,the research on the miniaturization design of flexible microstrip antenna sensor is of great significance.In this paper,the modeling and simulation,parameter optimization,miniaturization design and application of flexible microstrip antenna sensor are studied.In order to make the flexible microstrip antenna sensor flexible and easy to bend,felt and copper foil are selected as the dielectric material and conductive material respectively.Combined with the transmission line model of microstrip antenna and HFSS software,the model of 2.45 GHz traditional flexible microstrip antenna sensor is established,and the final parameters of the traditional flexible microstrip antenna sensor are obtained through parameter optimization.In order to improve the wearability of flexible microstrip antenna sensor,the miniaturization design method of flexible microstrip antenna sensor is studied.In this paper,the design of miniaturization of flexible microstrip antenna sensor is studied by loading rectangular slot on the surface of radiation patch of traditional flexible microstrip antenna sensor.In order to increase the miniaturization effect of the flexible microstrip antenna sensor,the long side of the rectangular slot is placed perpendicular to the direction of the current flow on the surface of the radiation patch,which maximizes the effective path of the current flow on the surface of the radiation patch after loading the rectangular slot.Secondly,the rectangular slot parameters are simulated and analyzed,and a set of rectangular slot parameters are determined to make the flexible microstrip antenna sensor loaded with rectangular slot not only have smaller resonance frequency,but also meet the impedance matching as much as possible.Finally,by reducing the size of the radiation patch and adjusting the position of the feed point,the flexible microstrip antenna sensor has a resonant frequency of 2.45 GHz and meets the impedance matching,so as to realize the miniaturization of the flexible microstrip antenna sensor.The simulation results show that compared with the traditional flexible microstrip antenna sensor,the size of the radiation patch is reduced by about 44.1%,and the SAR of the miniaturized flexible microstrip antenna sensor is far less than the international standard value.Finally,the traditional flexible microstrip antenna sensor and the miniaturized flexible microstrip antenna sensor are developed,and the calibration experiments and bending measurement experiments of the two sensors are carried out respectively.The results show that the deviation between the measured and simulated resonant frequency of the traditional flexible microstrip antenna sensors is small,which meets the design requirements,and can identify different degrees of curvature according to the change of resonant frequency of the sensor.Therefore,this kind of flexible microstrip antenna sensor can be used in the wearable field to measure the bending of human joints.