Analysis of distributed multi-finger high-power transistors using the FDTD method

The FDTD method has been used for the EM analysis of the power scaling versus gate periphery in distributed multi-finger, large area RF power transistors, such as RF LDMOS, the dominant technology in cellular base-station applications. Results show that, regardless of transistor optimization for better RF performance, there is a strong degradation of the RF power density when scaling multi-finger dies to large size, due solely to EM effects. Therefore, EM effects within the active region of the transistor should be thoroughly accounted for in the design process of transistors for ultra high power amplifiers.