Liquid Crystal Tunable Filter Based On DBR Topology

The use of liquid crystals for tunable devices has already been investigated for phase-shifters and antennas in planar technology. Here, the focus is, first, on a half-wavelength open-circuited stub resonator, then on a second-order dual behavior resonator filter. To have the benefit of liquid crystal anisotropy and thus obtain agility, a bias voltage is applied to the device under study. In order to avoid the shift observed between simulated and measured results of the half-wavelength open-circuited stub for the first structure, the technological process has been improved for the second one in the aim to reduce mismatching and LC leaking.