Design and Fabrication of Long-range UHF RFID Reader Antenna with Protection Cover

Abstract

This research introduces a circularly polarized, long-range UHF RFID reader antenna featuring a protective cover. The antenna's truncated patch structure, designed using an air-substrate patch antenna, ensures circular polarization. Experimental results demonstrate that the antenna achieves 840–890 MHz of impedance bandwidth with a Voltage Standing Wave Ratio (VSWR) of less than two. Additionally, the Axial Ratio (AR) remains below 3dB within the 860-870 MHz bandwidth. The simulation results reveal that the antenna achieves an Axial Ratio (AR) bandwidth ranging from 860 to 870 MHz at 3 dB, along with an impedance bandwidth spanning from 830 to 900 MHz. Notably, the antenna consistently maintains an average gain of 9.2 dBi throughout the entire 3-dB AR bandwidth. Measuring 260×260×20 mm, the antenna is both compact and lightweight. CST Microwave Studio is employed to analyze the aluminum sheet metal antenna design, operating at 865-868 MHz. Inexpensive, lightweight, and simple to construct, the antenna's cover is fabricated via 3D printing, offering protection from environmental factors such as moisture and dust. The antenna's performance is evaluated using various materials for the cover, with PETG material being selected for optimal frequency tuning. The experimental and simulated results show a significant correlation, which makes the suggested antenna a perfect option for long-range UHF RFID applications.