Metamaterial-Based, Vertically Polarized, Miniaturized Beam-Steering Antenna for Reconfigurable Sub-6 GHz Applications

A miniaturized, vertically polarized (VP), pattern switchable/beam-steering antenna based on a metamaterial radiator is presented for sub-6 GHz applications. Different from the traditional split-ring resonator (SRR), the proposed T-shaped SRR can work as a miniaturized VP omnidirectional radiator. To steer the radiation beam, a novel switchable mushroom reflector with a low profile and low loss is explored and utilized. Multiple switchable mushroom reflectors are loaded around the T-shaped SRR radiator to obtain various steerable beams. To verify the proposed design principle, a VP beam-steering SRR-based antenna with a compact size of 0.36 λ
₀
 × 0.36 λ
₀
 × 0.07 λ
₀
is designed by loading four mushrooms. By controlling the
off
/
on
states of four switches, the proposed reconfigurable antenna can realize beam-steering in the horizontal plane (eight states with 45°-step). The measured overlapped −10 dB impedance bandwidth is wider than 3.40–3.80 GHz (11.1%), and the realized peak gain is larger than 5.3 dBi. Therefore, the proposed antenna is a good solution for the widely deployed fifth generation (5G)-NR and smart antenna applications due to its compact size, flexible beam-steering capacity, broad bandwidth, and good scanning coverage.