A switch bias system is provided that includes a bipolar junction transistor (BJT) switch comprising a base, emitter, and collector; a current sense circuit coupled to the emitter, the current sense circuit configured to sense current flow through the emitter of the BJT switch; and a proportional bias circuit configured to generate a bias current to the base of the BJT switch, the bias current set to a fixed proportion of the sensed current flow through the emitter of the BJT switch.