The frequency response of all oxide field-effect transistors with amorphous LaAlO3 on a crystalline SrTiO3 substrate is reported. The intrinsic cut-off frequencies of 4 mu m gate-length devices are found to be approximately 17 MHz indicating that with gate length scaling gigahertz cut-off frequency is possible. The low cut-off frequency is primarily limited by the low effective mobility. The estimated effective mobility value determined from the S-parameter measurement is 3.8 cm(2)/Vs, which is consistent with previous reports. Small-signal equivalent circuit model parameters are extracted by fitting to on-wafer measured S-parameters. Good agreement is obtained between measured and simulated S-parameters based on the equivalent circuit model. (C) 2012 Elsevier Ltd. All rights reserved.