A novel broadband reflectarray antenna with lattice stubs on square element for Ku‐band application

In this article, a single layer unit cell reflectarray antenna comprising a fixed square patch to which is attached a lattice of symmetric open ended stubs is proposed. The phase response of the proposed unit cell element is governed by the length of the lattice, providing more than 600° of reflection phase variation. The unit cell element of 0.54λ 0 × 0.54λ 0 , has a thin dielectric substrate thickness of 0.036λ 0 and is placed above an air layer making the overall unit cell thickness of 0.126λ 0 . A 15 × 15 elements Ku‐band reflectarray antenna is designed with an area of 18 × 18 cm 2 . The reflectarray is center fed by a linearly polarized pyramidal horn antenna. The planar reflectarray antenna is fabricated and has wide −1 dB gain bandwidth, about 20% covering 12.1–14.8 GHz. The measured antenna gain at 13.5 GHz is 25 dB which is equivalent to 39% efficiency. The proposed unit cell and the reflectarray antenna are simulated through CST and HFSS software packages.