Jessica Li
Research Mentor: Steven Young
Mentor Department: Department of Electrical Engineering and Computer Science, Engineering
Author(s): Jessica Li, Nick Ventresca, Anthony Grbic, Steve Young
Session: Session 7 (4:00 PM – 4:50 PM)
Presentation Type: Oral Presentation
Abstract
Space-time modulation has attracted growing interest in radio frequency (RF) circuits, applied electromagnetics, and optics because it enables applications such as filtering, frequency conversion, parametric effects, and nonreciprocal transmission. Recent advances in tunable semiconductor devices, as well as electro-optic, magneto-optic, phase-change, and 2D materials, have made experimental demonstrations of these effects more feasible. In this project, I investigate space-time modulation experimentally using a transmission-line-based test platform at microwave frequencies. The goal is to verify theoretically predicted effects and study practical behaviors that are difficult to capture fully in simulation, such as stability, noise performance, and the effects of nonidealities and parasitics. To do this, I designed a periodically modulated transmission line with four unit cells using time-modulated varactor diodes to achieve frequency conversion from 1 GHz to 1.5 GHz. I selected components and designed a printed circuit board layout to realize the modulated system, and then simulated the expected performance using ADS Momentum and Ansys HFSS. This also involved designing supporting circuits such as filters and bias tees for the time-varying pump. After fabrication, I assembled the printed circuit board and used microwave measurement instruments to characterize its performance and observe the effects of time-varying modulation.
