Thermal analysis of fully integrated RF single-package module for GSM quad band handsets

The thermal analysis of fully integrated RF single-package module (RSPM) for GSM quad band handsets is presented. The RSPM includes RFIC transceiver, GaAs power amplifier (PA), SP6T RF switch, and RF SAW filters in addition to control circuitry and matching components. Multi-layer laminate organic substrate has been chosen due to lower cost than LTCC substrate and maturity of the technology. Size of the RSPM is 13mm × 13mm × 1.5mm. The thermal impact mainly caused by high power amplifier affects the electrical performance of RF SAW filters and this result in Rx sensitivity degradation of RSPM in in-band edge. Three-dimensional tangential vector finite element method (FEM) model is used to predict the optimal RSPM design with good electrical performance and lower costs, while maintaining reasonable thermal performance. An infrared microscope system is used to measure RSPM temperature with both RF and dc power. The comparison between the numerical and experiment data indicates agreement with less than 14.5% difference in peak temperature. The optimal distance from SAW filters to GSM PA and optimal number of thermal vias under the SAW filter area are 7.1mm and 4, respectively. The measured results of RSPM show reasonable thermal performance and good electrical performance.