Methods, systems, and apparatuses for RFID devices, such as reader antennas, are described. A reader antenna includes a quadrature
hybrid coupler, a termination element, and an antenna, such as a
patch antenna. The quadrature
hybrid coupler has first, second, third, and fourth ports. The first port receives an input
radio frequency RF
signal. The second port outputs a first RF output
signal. The third port outputs a second RF output
signal. The second RF output signal is shifted in phase by 90 degrees relative to the first RF output signal. The fourth port is coupled to the termination element. The
patch antenna has a first point coupled to the first RF output signal and a second point coupled to the second RF output signal. The
patch antenna radiates a circularly polarized RF signal due to the received first and second RF output signals. The circularly polarized RF signal may be used to interrogate tags. 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.