According to the effective medium theory,the average field inside a cell suspension was calculated by Maxwell-Wagner effective equation.Then,based on the second-order model for calculating the transmembrane voltage(ΔΨ) on a single cell exposed to an alternating field,an analytical model was derived for the ΔΨ on the cells in suspensions exposed to millimeter waves.The model shows that the ΔΨ on a cell in suspensions depends on the frequency and amplitude of the external field,cell arrangement,and cell volume fraction.