Spider Web shaped Near-field UHF RFID Reader Antenna for Healthcare and IoT Applications

This paper presents a spider web-shaped antenna for near-field UHF RFID applications. The proposed design consists of concentric decagons, and open-ended microstrip lines etched on the circular substrate. The proposed design features a uniform and fairly strong electric field distribution in the nearfield region. In addition, this antenna exhibits impedance matching ranging from 902 MHz - 925 MHz and further poses low gain characteristics, that is required for most of the nearfield application in order to avoid misreading of other tags. Moreover, this design provides symmetric current distribution throughout the structure, thereby solves orientation sensitivity problems of low-cost linearly polarised tag antennas. The measurement results demonstrate tag can successfully read expensive jewellery items, tagged pills and tag placed in different orientations. Therefore, the proposed reader antenna is a good candidate for near field RFID, health care and IoT Applications.