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

Because of the poor thermal conductivity of GaAs, successful power MMIC amp lifier design in coplanar technology requires careful thermal consideration s. The influences of the active device geometry and mounting conditions hav e been investigated theoretically and experimentally to provide reliable th ermal management design data. Fifty-mum substrate thinning and flip-chip mo unting with thermal bump attachment on aluminum nitride (AlN) or diamond he at sinks exhibited temperature rises of the order of 50 degreesC and 40 deg rees to 30 degreesC, respectively, leading to significant improvement in th e performance of coplanar power devices and circuits. These results demonst rate the potential of coplanar MMIC technology for high power applications.