Dual-Resonance Continuously Beam-Scanning X-Band Reflectarray Antenna

In this article, a 7 x 7 reconfigurable reflectarray operating at X-band is proposed and experimentally verified. The reflectarray consists of linearly polarized, dual-resonance, tunable unit cells fabricated on a single layer. Reconfigurability is achieved by loading each dual-resonance unit cell with four varactors; the two resonances provide a phase range greater than 360 degrees . The unit cell design utilized in this reflectarray is analyzed using full-wave Floquet simulations. A biasing network supporting individual biasing of each array element is designed, allowing beamsteering in E-, H-, and diagonal planes. The proposed reflectarray is evaluated using both full-wave simulations and measurements. To facilitate measurements, a fused filament deposition 3-D printer is used to fabricate an antenna mounting fixture using micrometer stages to make fine adjustments for the final alignment. A measured gain of 15.03 dBi, 3 dB gain fractional bandwidth of 7.81%, and continuous beam scanning are demonstrated in multiple planes from -50 degrees to +50 degrees at 10.1 GHz.