Low-Profile Circular-Polarized Filtering Transmitarray Antenna in V-Band

This communication introduces a low-profile circular-polarized (CP) filtering transmitarray antenna operating in V-band frequencies. The proposed antenna is composed of three well-designed components: the metamaterial filtering surface, reflective polarization rotator, and planar filtering illumination source. The filtering surface inherently possesses threefold functionalities: the ${y}$ -polarization to circular polarization converter with filtering capability, full-span $2\pi $ phase compensator, and reflector for ${x}$ -polarization. Different from the conventional illumination source with a 3-D horn structure, the proposed one has a planar configuration and presents excellent filtering characteristics. It is integrated with the reflective polarization rotator, which can reflect a linear-polarization incident wave with 90° polarization rotation. Thanks to the double filtering contribution made by the filtering source and filtering surface, the proposed transmitarray antenna shows excellent filtering performance. Its low profile is achieved by applying the folded propagation concept and adopting the planar feeding strategy. Featuring the merits of outstanding filtering response, stable CP radiation, easy integration, and low profile, the proposed antenna is promising for applications in high-speed millimeter-wave communications.