Reconfigurable planar metamaterial unit cell

A new reconfigurable metamaterial unit cell is introduced. DC-biased controlled PIN diodes are embedded in the structure of this unit cell so that its configuration can be controlled by switching the diodes. The presented unit cell operates in two different modes. In the first mode, which is called the horizontal mode, the unit cell shows an effective permittivity and permeability close to one which leads to a refractive index around 1, whereas at the other mode, which is called vertical configuration, it possesses a double positive behaviour for the constitutive parameters and shows a refractive index of 2. Both modes are simulated using a lumped-element model for the embedded PIN diodes and the constitutive parameters are extracted using a well-known algorithm. To validate the results, the unit cell is fabricated and the free-space method is used to measure the S-parameters of the unit cell. This unit cell will be used in advanced antenna applications.