| Popis: |
We discuss a method for the production of microwave polymer-dispersed liquid-crystal devices. We also show how to obtain a fine grained uniform fibrous polymer network. We then measure how the microwave-band dielectric properties and response-time characteristics of microstrip-line-type polymer-dispersed liquid-crystal devices vary with polymer concentration, and we measure how their response-time characteristics vary with the thickness of the polymer-dispersed liquid-crystal layer. With a layer thickness of 50 /spl mu/m, an applied voltage of 100 V and a polymer concentration of 7 wt%, we show that the decay time can be reduced to approximately 1/30th that of a plain liquid crystal at the expense of an increase in rise time of approximately 2.5 times and a deterioration of dielectric birefringence of approximately 50%. Finally, we discuss the results obtained with a prototype polymer-dispersed liquid-crystal loaded variable phase shifter in the 15-GHz band. By comparing the variable phase and response time of this phase shifter with basic experimental data obtained by the microwave resonance method, we verified the validity of these values. |
