Performance improvement of intelligent u-Port system using metallic object applications

摘要

The term u-City implies a next generation information city with innovative general functions that improve the convenience and quality of city life, guarantee safety and welfare through systematic city management, and create new businesses by combining advanced information communication infrastructures and ubiquitous information services with urban spaces. A u-City constitutes a pleasant city life for urban residents as well as effective city management for city managers. u-Port businesses, which represent an ubiquitous port in which all facilities related to port operations share information without any limitations through networks, have recently been highlighted. In particular, u-Port businesses use a specific ubiquitous technology to manage containers that has been recognized as a new scale for managing port logistics. However, as conventional technology is based on sensors, which represents a disadvantage in terms of initial and maintenance costs, studies on RFID-based technologies have largely been conducted. As conductive substances such as an aluminum can, metal box, or cigarette foil packet can improve both antenna directivity as well as have great effects upon antenna performance parameters such as resonant frequencies and radiant efficiency, it is difficult to build on RFID system. Under these circumstances, implementation of a tag antenna without deterioration has become an important task. In this paper, we assess the performance of a metallic object application in an intelligent u-Port system. In the proposed design, the antenna structure consists of square-shaped power feeder connected to the body for coordination with an attached common-use tag chip, whereas the patch device is manufactured in the form of multiple meanders to efficiently scale back the size of the antenna body. The characteristics of bandwidth, efficiency, and recognition distance were compared and analyzed based on the size of the proposed antenna and the number of folds. It was found that the efficiency and gain characteristics change according to the size of the antenna, and the number of folds in the form of meanders have a significant influence over recognition distance of the antenna.