Determining timing for isothermal pulsed-bias S-parameter measurements

S-parameters measured under pulsed conditions are shown to vary from their steady-state values with pulse measurement width and pulse repetition rate. A method is presented for determining suitable timing for isothermal, pulsed-bias, pulsed-RF, S-parameter measurement of GaAs devices. Variation of S-parameters with wafer temperature and with measurement duration and duty cycle are correlated.