Full reflection phase dynamic tuning using active impedance surface with dual poles and one zero

A tunable impedance surface with full 360° reflection phase control is presented. It removes the phase tuning deficiency in the conventional approaches. The half unit cell can be modeled as two parallel resonance tanks in series, providing the 360° reflection phase variation within a finite frequency band. By tuning the varactors integrated into the unit cells, the frequency band of the 360° phase variation can be shifted so as to produce a frequency region where the reflection phase can be tuned freely within 360° fully. Theoretical analysis and simulation results are validated by the experiment. The proposed approach can be applied for fine and full phase tuning, e.g. beam steering in reflectarray antennas.