A Wideband 20 to 28 GHz Signal Generator MMIC With 30.8 dBm Output Power Based on a Power Amplifier Cell With 31% PAE in SiGe

High-frequency systems such as mm-wave radar transmitters and LO/RF driver 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 cost 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 MMIC was developed that achieves 28.7 dBm peak output power with 21.9% PAE and over 27.4 dBm of output power over the 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. The signal generator is based on a VCO, power amplifier cells (PA cells) and lumped-element Wilkinson power combiners/dividers. The VCO's phase noise is less than -96 dBc/Hz at 1 MHz offset over the entire frequency range. The developed single PA cell achieves a maximum saturated output power P_sat of 24.7 dBm with peak PAE of 31%. This article describes the design and performance of all components. The signal generator MMIC has been integrated in an evaluation board together with a PLL, power supply, and serial interface.