One-bit wideband reconfigurable reflectarray with stable beam-scanning gain for X-band application

A wideband and electrically reconfigurable reflectarray (RRA) is presented for X-band application. The unit cell is composed of two heterogeneous resonators, that is, a split resonator ring and a metallic patch, and two positive-intrinsic-negative (PIN) diodes integrated between these two resonators. A bias circuit on the bottom layer is designed to achieve the switching of the two states via properly placing the PIN diodes on the resonators with minimal electric field. One-bit phase quantization is obtained by switching two different resonant mode via controlling the ON or OFF state of two PIN diodes. The simulated results show that the proposed unit cell can achieve one-bit phase quantization with 180° ± 20° and reflection coefficients of -1 dB from 9.5 to 10.8 GHz, corresponding relative bandwidth of 12.81%. In addition, a fully functional 12 × 12 RRA fed by a linearly polarized horn is theoretically designed, simulated, and fabricated. The measured results show that the main beam can be steered from −50° to +50° at operating frequency, for example, 10.1 GHz with 1.5 dB gain loss within the scanning range and 20.34% aperture efficiency. In addition, the measured average gain is about 17.5 dBi and 3 dB gain bandwidth is about 15.68% from 9.4 to 11 GHz. In virtue of wide bandwidth, stable radiation gain, and good beam scanning capability, the proposed RRA is promising for future wireless communication and radar.