Metal Only Spiral Slot Reflectarray Element Operating at 66 GHz

A metal-only reflectarray element operating in V-band (50-75 GHz) is proposed in this paper. By utilizing slots into the design, the dielectric substrate can be removed and replaced with an air gap. A slot based reflectarray element typically have a very limited phase curve. In contrast, in this paper, we show that multiple slots can result in a desirable phase range of 360°. The designed element consists of a square slot in the center of the unit cell with straight slots extending from its four corners to form resonators. The maximum loss of the element was less than 0.6 dB at the design frequency of 66 GHz.