LOW RETURN LOSS RUGGED RFID ANTENNA

摘要

Methods, systems and apparatuses for RFID devices, such as reader antennas, are described. A reader antenna (304) includes a quadrature hybrid coupler (314), a termination element (324), and an antenna (304), such as a patch antenna. The quadrature hybrid coupler (314) has first (316), second (318), third (320), and fourth (322) ports. The first port (316) receives an input radio frequency RF signal (306). The second port (318) outputs a first RF output signal (308). The third port (320) outputs a second RF output signal (310). The second RF output signal (310) is shifted in phase 90 degrees relative to the first output signal (308). The fourth port (322) is coupled to the termination element (324). The patch antenna (304) has a first point (412) coupled to the first RF output signal (308) and a second point (414) coupled to the second RF output signal (310). The patch antenna (304) radiates a circularly polarized RF signal due to the received first and second RF output signals. The circularly polarized RF signal (312) may be used to interrogate tags ( 102). Furthermore, the reader antenna is integrated into a ruggedized structure that provides environmental protection for the antenna, including providing shock absorption for impacts to the antenna.