Deisign Of Key-Band Antenna And Research On RFID Detection For Handheld Terminal

With the rapid development of science and technology, the wireless communication technology changes greatly, and the handheld wireless devices are used more and more widely, such as mobile phone, RFID. Due to its high transmission speed and long-distance transmission ability, the long-term evolution (LTE) has become a popular mobile network technology. For today’s communication environment, it is desirable for the latest mobile phone internal antenna to be compatible with both LTE and existing 2G/3G networks. However, the wide range of the involving bandwidths in the LTE, especially the bandwidth requirement at the low band, makes the internal antenna design a big challenge for the compact volume of cellular phone. UHF RFID is a better solution than the barcode in many ways like more storage space, information rewritability, process tracking, and becomes more and more popular in warehouse and logistics applications. In many cases the tags on the targeted good are arbitrary as horizontal, vertical or in the middle. There is a strong need from RFID reader user to know the reader signal strength and polarization. In the past this can only be measured from chamber, of course, very inconvenient and expensive.For the application requirements of handheld terminal wireless equipment antenna and UHF RFID system, this paper has carried on following research:First, we review the development process and design challenges of mobile phone and RFID reader, and introduce a variety of basic antenna theory and common antenna. We also provide the rectifier circuit analysis.In the second part, we design two antennas for key-band of handheld terminal, one is WLAN antenna covering 2.4 GHz and 5.8 GHz, and the other is LTE antenna which covers eight bands, including 700/850/900/1800/1900/ 2100/2300/2500.Finally, we design a receiving antenna and rectifier circuit for the UHF RFID, and then form a rectifier system after joining a transmitting antenna. It’s rectification efficiency meets the requirements, and the system can be used to detect the RFID reader’s signal strength and polarization.