A Reflector Antenna With Integrated Frequency- Selective Metal-Only Reflectarray for Dual-Band Operation

This paper presents a dual-band metal-only antenna that operates at 20 and 40 GHz. The unit cell consists of a square waveguide with short circuit termination and a square metallic block in the center. Its performance is evaluated and analyzed in detail. The proposed metal-only antenna combines the functionalities of reflectarray and parabolic reflector antennas. At 20 GHz, the reflected beam is determined by a parabolic surface. At 40 GHz, the reflected beam is controlled by the phase distribution of cells in the antenna. The gain increases with frequency in the lower frequency band, which is similar to what happens in a parabolic reflector antenna. The antenna profile is significantly reduced and the antenna's performance is improved after rotating the coordinate system. The antenna with reduced profile is fabricated using selective laser melting 3D printing technology. The measured results show that the proposed antenna can operate as parabolic reflector and reflectarray in the target two frequency bands.