US Patent 11529633 Printed circuit board heater for an amplification module

An apparatus includes a substrate, a first heating element, and a second heating element. The substrate includes a first portion, a second portion, and a third portion that is between the first portion and the second portion. The first portion is characterized by a first thermal conductivity, the second portion is characterized by a second thermal conductivity, and the third portion is characterized by a third thermal conductivity. The third thermal conductivity is less than the first thermal conductivity and the second thermal conductivity. The first heating element is coupled to the first portion of the substrate, and is configured to produce a first thermal output. The second heating element is coupled to the second portion of the substrate, and configured to produce a second thermal output. The second thermal output is different from the first thermal output.