Single-Layer Shared-Aperture Dual-Band Reflectarray Antenna with High Aperture Efficiency

A novel single-layer shared-aperture dual-band reflectarray is proposed, operating in the Ku-band and K-band. The reflection units of two frequency bands are alternately distributed on the same dielectric substrate, and a nearly 360° phase shift is achieved by changing the size of the reflection units. Based on this, a square reflectarray operating at 15.3 GHz and 21.6 GHz with an aperture diameter of 128 mm is designed, which consisting of 20×20 K-band reflection units and 10×10 Ku-band reflection units. At 15.3 GHz, the gain is 21.9 dBi and the aperture efficiency is 29%. At 21.6 GHz, the gain is 27 dBi and the aperture efficiency is 47%. In addition, the sidelobe levels are below -19.1 dB.