Dual-Band Transmitarray Architecture for Low-Profile Design

In this work a novel dual-band transmitarray antenna (TA) design is presented. The proposed TA operates at 12 GHz and 14 GHz exploiting an interleaved lattice configuration where two unit-cells operating at 12 GHz and 14 GHz respectively, are interleaved along the TA aperture. For each band the unit-cell consists of a frequency selective surface featuring two microstrip patch antenna coupled through a SIW cavity. The unit-cell has a size of 0.22 λ0 × 0.22 λ0 (with λ0 defined at 12 GHz) resulting in a periodicity of 0.44 λ0 at 12 GHz and 0.52 λ0 at 14 GHz. Such a high miniaturization of the unit-cell sizes leads to an extremely limited sensitivity to oblique incidence, allowing for a low-profile TA design. The unit-cell achieves a 360-degree phase range at 12 GHz with an insertion loss of 3.2 dB, maintaining this performance up to a 60-degree oblique incidence. Similarly, at 14 GHz, it exhibits a 360-degree phase range with an insertion loss of 3.1 dB under the same incidence conditions.