Reconfigurable unit cell for reflectarray antenna based on barium-strontium-titanate thick-film ceramic

Reconfigurable unit cells based on the ferroelectric thick-film ceramic of Barium-Strontium-Titanate (BST) are presented in this paper, which enable the realization of low-profile, cost-effective and fast steerable reflectarray antennas in X-band. A microstrip patch antenna partitioned into two halves is patterned on top of a screen printed BST thick-film. By applying a variable DC bias voltage between the halves, the resonance frequency of the capacitively loaded patch is shifted, and in the same time, a phase shift of the reflected wave is achieved. The method of using a waveguide simulator as the periodic boundaries in both simulation and measurement is also addressed.