Wideband Phase Switched Screen based on Tunable Artificial Magnetic Conductor Surface

The phase switched screen for cloaking is realized by periodically control two working states of the screen, i.e. inphase reflection and out-of-phase reflection, and therefore the ideal phase difference between the two states is π. In this paper, it is proved that, the effective phase difference between the two states might be in a range other than a single value; based on this finding, a new technique of enhancing the bandwidth of the phase switched screen (PSS) is proposed. The wideband PSS is consist of a tunable artificial magnetic conductor (AMC) and a biasing network controlled by periodical switch sequence, while the tunable electromagnetic band gaps are realized through varactors. By controlling the voltage of the varactors properly, the in-phase reflection frequency of the AMC can be tuned from 2.15GHz to 3.23GHz, and the phase differences between adjacent states are all fit in the effective phase difference range, and hence a broadband phase switched screen is realized. Based on a new proposed AMC structure, we finally realize a phase switched screen with the relative bandwidth of over 40%.