10-GSymbols/s Supply Modulated 250-GHz SiGe HBT Transmitter RF Front-End with 6.8-dBm Peak Modulated Power

A 250-GHz SiGe HBT (fT and $\mathrm{f}_{\text {max }}$ of $\mathbf{3 0 0} \mathbf{~ G H z}$ and 450 GHz) transmitter RF front-end using supply modulation at 10GSymbols/s along with a 16-customized-APSK (APSK ${ }_{c}$) constellation is used to generate instrumentation limited 40-Gbps signals with a peak modulated power of 6.8 dBm and an EVM of -18.9 dB, while consuming $\sim 1 W$ of DC power. The peak modulated output power and efficiency for the average modulated power generation of the transmitter RF front-end is 3 X and 2.3 X higher than when conventional QAM modulation with a backoff is employed. The $6.8-\mathrm{dBm}$ peak modulated power is the highest among the reported in literature.