A 3-D-Printed mm-Wave Reflectarray With Coaxial Unit Cells

A metallic 3-D-printed reflectarray (RA) based on a novel coaxial unit cell (UC) is presented herein for mm-wave applications. A full phase tuning range is achieved by varying the UC depth. The UC design allows for incident wave polarization independence and operability over a wide range of frequencies. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$16\times 16$ </tex-math></inline-formula> RA utilizing the proposed UC is designed, simulated, fabricated, and characterized. Furthermore, the RA performance is benchmarked against a conventional RA with printed square microstrip patch UC. The simulated and measured radiation patterns of both RAs in the E-plane demonstrate the achievement of accurate beam steering at the desired angle. The proposed RA is shown to have a higher gain (25.8 dBi) and efficiency (54%) compared to the conventional RA constructed using printed circuit technology. The proposed RA design is deemed promising for applications with stringent environmental conditions.