Antenna Design For UHF RFID Applications

Radio frequency identification(RFID)technology is a non-contact automatic identifycation technology that utilizes radio frequency signals to realize information transfer through spatial coupling(alternating magnetic field or electric field).Because RFID technology shows many advantages compared with other identification technologies,RFID technology has been greatly developed in the past few decades and formed a research boom at this stage.Various types of reader antenna design cases are given in the article(such as miniaturized antennas,multi-band antennas,wide-band antennas,wide-beam antennas,space diversity antennas,and near-field antenna),and their performance and characteristics are described in detail.This paper describes the working principle of the radio frequency identification system and the key parameters affecting the process of identification based on the theory of electromagnetics.It also focuses on introducing the evaluation parameters of the reader antenna on the RFID system.In addition,the design basis and method of the RFID reader antenna are introduced.In this paper,the main emphasis of research is to design the RFID reader antenna for different application scenarios,and then three types of RFID reader antennas are designed for three different application scenarios.In the process of antenna design,this article has always considered and explored the problems existing in current RFID systems and sought solutions.In this paper,firstly,a wide band RFID reader antenna withs working frequency band of 860-960 MHz has been designed,which is suitable for RFID reader antenna applications in RFID systems in the global frequency band.In addition,a circulator is added for the application scenario of multiple reader antennas in a channel door reading system,which effectively reduces the problem of “misreading” in the reading system.Secondly,a wide beam reader antenna with working frequency range of 918-928 MHz has been designed.The 3 dB radiation beam width of the antenna is 1060,which is wider than the conventional antenna,so that the read range of the RFID system can be effectively expanded.Finally,a multi-band reader antenna designed for multiple systems is designed.The antenna can work in RFID,GPS and WIFI bands at the same time,for a single antenna operating in multiple systems,a clever use of the duplexer(also known as the antenna diplexer)to solve the problem of coupling between the system is too strong,and completed the design.In this paper,professional electromagnetic simulation software is used to optimize the size of the designed antenna model,and the physical object of the antenna is processed using CAD drawings.Then,the fabricated antenna is tested and adjusted to obtain an RFID reader antenna that meets the design specifications.Finally,the designed reader antenna was applied to the RFID system and tested to obtain satisfactory results.