A 24GHz signal generator with 30.8 dBm output power based on a power amplifier with 24.7 dBm output power and 31% PAE in SiGe

High-frequency systems such as mm-wave radar transmitters and LO/RF chains in vector network analyzers (VNAs) often require the generation of signals with high output power. While these systems benefit considerably from the reduction in size and weight provided by SiGe integration, their output power must be further increased in order to meet the performance of other technologies (e.g. GaAs). To this end, a SiGe signal generator was developed that achieves 28.7 dBm peak output power with 21.9% of PAE and over 27.4 dBm of output power over its whole frequency range from 19.7 GHz to 28.2 GHz. The output power is scalable with DC current up to a maximum of 30.8 dBm with 17.6% PAE. It is based on a voltage controlled oscillator (VCO), power amplifier cells (PA cells) and lumped-element Wilkinson power combiners/dividers. Its phase noise is less than -94 dBc/Hz at 1MHz offset over the entire frequency range. The developed single PA cell achieves a maximum saturated output power P_sat of 24.7 dBm with a peak PAE of 31%.