A 5.4W X-band gallium nitride (GaN) power amplifier in an encapsulated organic package

Gallium nitride (GaN) amplifiers are inherently well suited for high power applications, but their increased power densities call for high thermal conductivity (k) substrates, such as copper (Cu) or aluminum nitride (AlN), to provide adequate thermal management. Thus, low-cost/low-k substrates, such as organics, have been traditionally overlooked for GaN-based amplifiers. In this paper, an encapsulated package is investigated to circumvent the thermal limitations of liquid crystal polymer (LCP), one such organic, while leveraging its multilayer and microwave advantages. An X-band GaN PA in such a package has been designed and fabricated, showing a PAE of 38% and PSAT of 5.4W under CW operation, or 49% PAE and 7W PSAT at 50% duty cycle.