▎ 摘　　要

We studied the frequency and temperature dependence of the impedance of Si/SiO2-substrate graphene. dc resistance is a weak non-monotonic temperature function at low temperature, whereas it exhibits a negative temperature characteristic at high temperature. The frequency dependence of the impedance implies that one should he concerned with the renormalization in the complete understanding of graphene impedance at radio frequencies. As an application, we designed a sensitive temperature sensor at the range 70 degrees C-120 degrees C.