Increasing the speed of microstrip line-type PDLC devices

We measure how the microwave band dielectric properties and response time characteristics of microstrip line-type PDLC (polymer dispersed liquid crystal) devices vary with polymer concentration, and we measure how their response time characteristics vary with the thickness of the PDLC layer. The physical significance of these results is also examined. With a layer thickness of 50 μm, an applied voltage of 100 V and a polymer concentration of 7 wt%, we show that the decay time can be reduced to about 1/30th that of a plain liquid crystal at the expense of an increase in rise time of about 2.5 times and a deterioration of dielectric birefringence of about 50%. Also, by varying the PDLC layer thickness with a polymer concentration of 5 wt% and an applied electric field fixed at 1.8 × 10⁶ V/m, we show that increasing the layer thickness causes the decay time to increase and the rise time to decrease. The rise time obtained with a PDLC layer thickness of 100 μm is half the value obtained with a thickness of 20 μm, while the decay time is approximately 3.6 times larger.