A single-chip dual-mode CW/pulse electron paramagnetic resonance spectrometer in 0.13μm SiGe BiCMOS

Microwave circuitry for electron paramagnetic resonance (EPR) spectroscopy is implemented in a 0.13μm SiGe BiCMOS process. The chip can operate in both continuous wave (CW) and pulse modes. The frequency is tunable from 770MHz to 970MHz, corresponding to Zeeman magnetic fields from 28mT to 35mT for a free electron. The CW-EPR absorption line of a DPPH powder sample is acquired. The chip consists of a VCO, a PA, an LNA, a down-conversion mixer, baseband amplifiers, and a pulse generation block.