GPS-Integrated RFID Antenna With AMC Backing for IoT-Based Sensing and Tracking Applications

In this communication, a triple-band circularly polarized antenna backed with an artificial magnetic conductor (AMC) is presented for radio frequency identification (RFID) readers/Internet of Things (IoT) applications. The antenna is comprised of a spiral-shaped dipole pair that is printed on both sides of the dielectric substrate in a cross-dipole configuration. Delay lines are used in the designed antenna to connect the dipole elements and to achieve circular polarization (CP). The antenna is supported by a
$4\times4$
AMC surface placed beneath it at a distance of
$\lambda _{0}$
/10, where
$\lambda _{0}$
is the wavelength calculated at the lowest resonant frequency. The AMC backing results in gain enhancements of 3.06, 3.43, and 0.56 dB in the global positioning system (GPS) L1 (1.575), 2.45, and 5.8 GHz bands, respectively. Consequently, the reading range of the reader increases, as the gain increases. In the GPS L1 (1.575), 2.45, and 5.8 GHz bands, the proposed AMC-backed antenna has impedance bandwidths of (1.56–1.585 GHz), (2.39–2.53 GHz), and (4.7–5.9 GHz), respectively. The proposed antenna could be a suitable candidate for real-time implementation in RFID readers/IoT applications.