A Digital IR-UWB Transmitter With High Spectrum Utilization and AM-PM Distortion Calibration

This brief presents an IEEE 802.15.4z-compliant impulse-radio ultra-wideband (IR-UWB) transmitter for an indoor positioning system. Controlled by the digital baseband, a current-mode digital power amplifier (DPA) generates programmable pulse waveforms, ensuring optimal spectrum utilization and sidelobe suppression. Uniquely, it can directly measure AM-PM distortion caused by non-linear power networks, offering an exclusive compensation method to enhance linearity and elevate in-band spectrum utilization. As a proof-of-concept, a prototype was implemented in a 22-nm FD-SOI process. The measurement result demonstrates that the design can support channels from 6.5 to 10 GHz with 13 dBm peak output power. After calibration, the output spectrum has an in-band spectrum utilization of 81% at peak output power. The chip consumes 33.4 mW at a maximum output power spectral density of −41.3 dBm/MHz.