Based On The Pcb Designed Network Uhf Microstrip Antenna, Speaking, Reading And Writing

The Internet of Things has got an unprecedented opportunity for development under the impetus of the national12th Five-Year Plan, which will greatly change the production mode, as well as the lifestyle of the modern society. As a core technology of the Internet of Things, the RFID (Radio Frequency Identification) technology, especially the UHF (ultra high frequency) RFID technology will undoubtedly become a hot spot for the future development, depending on its advantages of long reading distance, fast reading and writing speed, etc. The great development of UHF RFID systems and the ever popular application of EPC tags will improve the efficiency of retail industry, logistics industry and product tracking, which will consequently bring an innovation in global logistics and international supply chain.There is an increasing demand on UHF interrogator in all walks of society nowadays, however only a few companies can design and produce this equipment. This leads to the high interrogator price on market. The UHF interrogator on the market today takes the same characteristics. For example, they all use the USB port or UART port to communicate with the host, which will limit the installation of the interrogator and as well make the interrogator no longer suitable for some remote read and write occasions. What’s more, the host computer normally takes limited hardware interfaces, so it is impossible to achieve real-time control of large numbers of interrogators. On other aspects, UHF interrogator is usually equipped with separated antennas. Besides the disadvantage of high price, separated antennas demands more attention on antenna installation and commissioning, making it more difficult to use the interrogator in practical application.For all the above reasons, this dissertation aims to design a low cost UHF interrogator, which integrates multiple user interfaces at the same time. The new interrogator can meet the diversity demand of the domestic market for UHF interrogator.UHF antenna takes the most important role in the communication between the interrogator and tag. The installation and commissioning of antenna affects greatly both the productivity and the read performance of the interrogator. An onboard antenna based on the theory of microstrip patch antenna is put forward for UHF interrogator in this article. This new antenna can be made together with the printed circuit board of UHF interrogator, which can simplify the procedure of antenna implementation. After the simulation with HFSS, The author designed the PCB of the new antenna and then regulated the manufactured PCB. The test result shows that this new antenna can meet the requirements of interrogator for antenna capability well.In order to reduce the production cost, discrete components are choosed to built the the RF circuit of the interrogator. To implement the function of remote and real-time interaction on the UHF interrogator, the hardware design of a networked reader using LPC2138as chief controller is put forward in this article, based on Ethernet controller ENC28J60. For the software implementation, the new interrogator supports the most popular ISO18000-6C standard. Besides this, the encoding process and decoding process of the commnication on the interrogator are all implemented by software which will keep down the production cost further more. The transplanting of real-time OS uC/OS-II and embedded TCP/IP protocol LwIP on LPC2138enables the interrogator to connect to Internet, making it possible to implement remote data interaction and configuration.