A Research On The Synthetic Design Of Near-field Antenna

Today,the economy and technology are developing rapidly.Emerging technology has brought about great changes in all walks of life,and led the emergence and development of emerging industries.With the growing maturity of 5g technology and Internet of things technology,as one of its core technologies,Radio Frequency Identification technology is more widely used in various fields of economic and social development,especially in recent years,those products related RFID technology play an indispensable role in the industries of self-service supermarket,intelligent home,intelligent wearable devices,etc.In the practical application of various industries,the working environment of RFID system is becoming more and more complex,and the layout of reader antenna tends to be intensive.Especially in the application of rapid positioning of goods,the control requirements for the working area of the system are more stringent,which puts forward higher requirements for the design of reader antenna.The new type of near-field antenna plays an effective and active role in the fast reading of multi-target short-range and the fast positioning of single target.In this paper,the antenna of near-field reader is designed reasonably by using the electromagnetic field leaked from the unclosed transmission line to achieve good group reading performance of the electronic tags in the working area and avoid misreading other tags outside the working area.At the same time,this paper summarizes the research process of near-field antenna and the quantitative data in the actual test process of tag reading.The data can improve the reference basis of antenna simulation parameters,such as gain,near-field distribution,polarization,etc.,which guide the design of near-field antenna.In this paper,several near-field antennas are designed before 885 MHz ~ 943 MHz,which can be used in different scenes of RFID system without additional structure for electromagnetic shielding.The far-field gain of the antenna is less than-10 dB and the electromagnetic field in the near-field area of the antenna is evenly distributed.The field value is less than 10 dB difference in the response area.In the meantime,the short-distance sharp attenuation of more than 30 dB can be achieved in the direction away from the antenna.The boundary between the response and non-response areas is accurate and regular,which can not only ensure that there is no missing tag in the working area,but also effectively prevent non-working area tags from being misread.The processed nearfield antenna is applied to the actual RFID system,which has a good effect in book borrowing and management,small-scale goods inventory,unmanned supermarket checkout and so on.This paper also introduces the application of this type of near-field reader antenna in small range positioning.We cleverly use the transmission line structure to realize the effective positioning of archives and book tags,and the simple antenna structure also greatly reduces the production cost.Finally,in the process of summarizing the design method of near-field antenna,inspired by the idea of machine learning,we use k-nearestneighbor algorithm to classify the characteristics of various antenna types,and successfully test the possibility of selection and recommendation of classification algorithm in antenna design,which plays an active role in resource integration and utilization.