Wideband Millimeter-Wave Microstrip Reflectarray Using Dual-Resonance Unit Cells

A wideband millimeter-wave reflectarray antenna is investigated. First, using the microstrip technique, a new dualresonance unit cell is proposed for the reflectarray, which provides an approximately linear phase response of 0°-360° range. Additionally, its phase response curves are nearly parallel within a broad band, which can widen the operating bandwidth of the reflectarray antenna. Then, using the proposed unit cells, a 1296-element reflectarray antenna is designed, fabricated, and measured. Finally, measured results show that the boresight gain is 31.9 dBi and the 1-dB bandwidth is greater than 29.3% at Q-band. Simulation and measurement results agree very well with the proposed design scheme.