Research

An overview of the major research themes of our group. Please visit our publications page for a comprehensive list. Feel free to contact us to learn more about any of these areas!

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Software-Defined Radios

A software-defined radio (SDR) ideally allows all of the parameters of a radio to be programmed dynamically. While the circuits on the baseband of radios are easily tunable, the RF front-end is not.

Our research has focused on developing methods of manipulating the impedance seen by the antenna using baseband circuits. We have achieved this using passive mixers connected directly to the antenna (without an LNA) with performance competitive with traditional radios. Our group has also developed circuit architectures to enable full-duplex communications for efficient spectrum usage.

Angle Sensitive Pixels

The original goal here was to be able to detect and localize luminescent or fluorescent sources in a 3-D matrix (i.e tissue) or solution without need for a lens and at very low cost/size. The key idea that made this possible is the Angle Sensitive Pixel or ASP. This structure, which can be made entirely using the layers of a standard CMOS process, detects information about the incident angle of light striking it by imaging the diffraction pattern formed by the Talbot effect. An array of ASPs captures the 4D light field allowing the ability to digitally refocus rays, estimate depth, and even localize light sources in a 3-D volume. Since then, we have spurred on multiple efforts at various levels of hierarchy, from opto-electronic device development inside of standard CMOS , circuit + system design (to handle and preprocess data from large numbers of ASPs), and machine learning and signal processing for plenoptic imaging, even optically computing the first layer of convolutional neural networks for energy-efficient deep learning!

Microelectrode Arrays

By combining very compact amplification and digitization of neural signals with angle sensitive pixels, we are building multi-hundred active electrode arrays intermingled with lensless imaging for simultaneous opto-electronic recording of neural tissue. We are also building on this, combined with techniques we have developed for low power, low noise neural recording to ultimately develop implantable opto-electronic neural probes.