Contribution of self heating to intermodulation in FETs

Self heating gives microwave FETs a temperature response to power dissipation. This is shown to be significant at high-frequency signal rates, even though the apparent time constant of heating is a few kilohertz. Self heating causes variation in intermodulation with frequency spacing and the extent of this variation is linked to bias. The frequency response of the heating process can be characterized from third-order intermodulation versus frequency spacing.