A medical device includes a handle assembly and a probe-and-amplifier assembly. The handle assembly includes a handle body defining a chamber therein. The probe-and-amplifier assembly includes a probe and a microwave amplifier unit. The probe extends distally from the distal end of the handle assembly. The microwave amplifier unit is disposed within the chamber. The microwave amplifier unit and the probe are mechanically coupled to one another to form a unitary body. The probe-and-amplifier assembly is selectively removable from the handle assembly.