The relatively high-mobility metal-oxide thin-film transistors (TFTs) have the potential to realize radio-frequency (RF) circuits operating in the megahertz regime. Here, we investigate the RF performance of amorphous indium gallium zinc oxide (a-IGZO) TFTs on the glass substrate with the sputtered channel layer. The device exhibits a high current density of 22.6 mA/mm by employing thin bi-layer Al2O3/SiO2 gate dielectrics. The 1.5 mu m gate length device achieves a current gain cutoff frequency f(T) of 384 MHz and a maximum frequency of oscillation f(max) of 1.06 GHz. The record high RF response among the amorphous oxide channels makes it possible to explore new large-area electronics applications, such as low-cost radio frequency identification (RFID) tags. Furthermore, the corresponding small signal parameters were extracted and the voltage dependences of RF response were studied. (C) 2014 Elsevier Ltd. All rights reserved.