Design of coplanar power amplifiers for millimeter-wave system applications including thermal aspects

Because of the poor thermal conductivity of GaAs, successful power MMIC amplifier design in coplanar technology requires careful thermal considerations. The influences of the active device geometry and mounting conditions have been investigated theoretically and experimentally to provide reliable thermal management design data. Fifty-ìm substrate thinning and flip-chip mounting with thermal bump attachment on aluminum nitride (AlN) or diamond heat sinks exhibited temperature rises of the. order of 50°C and 40° to 30°C, respectively, leading, to significant improvement in the performance of coplanar power devices and circuits. These results demonstrate the potential of coplanar MMIC technology for high power applications.