UC San Diego
Electronic Circuits for Communications and Sensing Applications
- Author(s): Levy, Cooper Sinclair
- Advisor(s): Mercier, Patrick P
- Buckwalter, James F
- et al.
This dissertation addresses two distinct topics, namely circuits for radio-frequency and millimeter-wave transmitters with emphasis on power amplifiers, and control circuits and system design for linearizing atomic magnetometers.
Power amplification for wireless transmitters, despite receiving myriad attention over the last few decades, is still one of the main bottlenecks in terms of complete transmitter integration and reducing system power dissipation. First, a distributed amplifier architecture aiming to improve peak efficiency by voltage supply scaling will be presented. By using multiple supplies, wasted headroom is eliminated in the early stages of the distributed amplifier where the output voltage swing is relatively low. Second, a class of Doherty power amplifiers that was rediscovered by the author by reverse engineering the canonical Doherty power amplifier, and a modern implementation, will be presented. The implementation stacks the voltage swings of the main and peaking amplifiers of the Doherty power amplifier, allowing increased output power in scaled CMOS without concern of breakdown. Finally, atomic magnetometers have shown promise as replacements in many applications where SQUIDs are currently used, with the benefits of no supercooling required, and the ability to operate in Earth's geomagnetic field. At the same time, operation outside of a magnetically-shielded environment has numerous side-effects. The last section will present a technique for linearizing the Bell-Bloom atomic magnetometer, improving its performance in interference-rich environments. The technique notes that the detected output signal of the magnetometer contains not only information about the spin precession of the optically pumped atoms, but also a large component due to the pumping laser modulation. By subtracting this known pumping modulation signal from the detected output, the system linearity can be significantly improved.