Dual-Polarized Endfire Phased Array Antenna with Forward Beam Coverage for IoT Devices

In this paper, a dual-polarized endfire phased array antenna (PAA) based on tilted-beam elements is presented to provide forward beam steering for IoT Devices. Each antenna element comprises two mirror-symmetric modules to generate ±45° polarizations, with their normal directions oriented to the endfire direction. Each module contains two dipoles with unequal lengths, excited by a 1-to-2 feeding network to achieve forward beam tilting. This achievement is helpful to avoid large grating lobes, even with large element spacing of 0.76λ in array design. To further suppress the cross-polarization level at the zenith, a gradient polarization metasurface (GPM) is placed tightly above the elements. It can provide additional polarization for the broadside beam, without influencing the endfire beam. A 1×6 dual-polarized PAA prototype operating in the 4.8 GHz band is fabricated. The measured beam steering range is from 0° to +70° with a 3.8-dB gain fluctuation, exhibiting forward and low-elevation coverage. Within this range, the measured side lobe level is below -7.9 dB, the cross-polarization level is below -9.7 dB, and dual polarizations are consistently maintained.