Liquid crystal-based composite material including electrically conducting elongated particles and having enhanced microwave birefringence

A phase modulating composite material having enhanced birefringence and being responsive to electric fields or magnetic fields applied thereto, comprising:

• liquid crystal material;
• and
• electrically-conducting, elongated particles dispersed in the liquid crystal material,
• wherein the elongated particles are alignable parallel with the liquid crystal material in response to the applied fields in a direction which is at a variably-controlled angle to propagation directions of microwaves or millimeter waves to be phase modulated.

A method for modulating the phase of a microwave, comprising the steps of:

• providing a microwave phase modulating cell comprising:
• a phase modulating medium, the phase modulating medium comprising a liquid crystal having a dispersion of electrically conducting, elongated particles therein, and
• means for controllably aligning the particles and the liquid crystal in a selected direction in the phase modulating medium;
• directing a beam of microwave energy through the cell in a microwave propagation direction;
• and
• controllably aligning the particles and the liquid crystal in the selected direction, which includes aligning the particles with the liquid crystal, thereby changing the microwave index of refraction of the phase modulating medium.