Liquid-crystal-based mm-wave tunable resonator

A new tunable planar resonator based on nematic liquid crystals (LC) substrate for applications at mm-wave frequencies is presented. The proposed structure utilizes an electric field bias to align the LC molecules, offering direct control over the dielectric properties (anisotropy) of the LC substrate. The LC used is a mixture commonly referred to as E7. A tunability of about 6% is achieved in the 30 - 60 GHz range; i.e. 1.94 GHz around 30 GHz and 3.58 GHz around 60 GHz. The proposed structure can also be exploited to realize miniaturized tunable filters with wide tuning range at mm-wave/microwave frequencies.