A Design of Dual-frequency 1-bit Unit Cell with Independent Phase Modulation for Reflectarray Antennas

An active reconfigurable reflectarray unit cell with independent phase modulation at two different frequencies is designed and analysed. A metallic ring is placed out of the metallic patch to introduce the second working frequency, and two PIN diodes are adopted to control the phase at 5GHz and 7.5GHz, respectively, whose equivalent circuits vary when the bias voltage applied across the diode changes. Simulated results are analysed carefully, showing that the element designed has two phase states with 180° differences at two frequencies by controlling the ON/OFF states of two diodes.