Voltage-variable microwave delay line using ferroelectric liquid crystal with aligned submicron polymer fibers

This letter describes a variable microwave delay line that uses a thick ferroelectric liquid crystal film stabilized by aligned polymer fibers of submicron diameter. The delay line consists of a microstrip transmission line with a 50-μm-thick liquid crystal film as the dielectric material. The conical axis of the helical alignment of the ferroelectric liquid crystal molecules can be anchored in the microwave propagation direction by aligned polymer fibers dispersed in the liquid crystal film without conventional alignment layers coated on substrates. The phase shift of microwaves passed through the device could be varied by applying a voltage across the film to loosen the liquid crystal helical alignment.