Electric field regulating behaviour of microwave propagation in ER fluids

The model of microwave propagation through electrorheological (ER) fluids has been established according to the experimental facts that the structure and the dielectric properties of ER fluids change with the external electric field. The theoretical simulation shows that the microwave transmittance increases with the dielectric constant of ER fluids if the dielectric constant of the ER fluids is larger than that of the container. Otherwise it decreases with the dielectric constant. The experimental results revealed that the microwave transmittance in the ER fluids could be adjusted by changing the DC field strength. The microwave transmittance increases with the field strength when the concentration of the fluid is low, but it decreases when it is high. The phenomenon that the microwave transmission could be adjusted in the ER fluids can be attributed to the changes of the structure and the dielectric properties of the ER fluids under the external electric field.