Monolithically Integrated Time-Varying Transmission Lines (TVTL) for Tunable and Interference Resilient RF Front Ends

Speaker: Xiating Zou
Affiliation: Ph.D. Candidate

Via Zoom: https://ucla.zoom.us/j/97421211692?pwd=YzNkanhJZVMwNmJvZ1Y3M1JLdkhZdz09

Abstract:  With the development of modern wireless communications, interference has become a primary challenge for spectrum utilization and coexistence. High frequency selectivity, tunable, low-noise, and high-linearity RF front-end components can greatly help the reception robustness under heavy interference scenarios. In this work, we propose to utilize the parametric mixing and amplification behavior of the time-varying transmission lines (TVTL) to design and implement such devices.

TVTLs are reactance-based circuits consisting of passive transmission lines whose inductance or capacitance is modulated by an electromagnetic wave called the “pump”. The single-sideband operation of a TVTL is especially favorable in that it can provide low-noise parametric amplification and frequency conversion with a moderate amount of gain. Moreover, TVTLs are compatible with modern IC technologies and can be realized with small form factors.

In this work, an in-depth theoretical study on the time-varying transmission lines (TVTL) in the single-sideband operation is presented. The theory then serves as a guideline to design three configurations of TVTLs on commercially available monolithic microwave integrated circuit (MMIC) processes. These MMIC TVTLs are then applied to design the RF correlator and the tunable peak amplifier to tackle the interference issues faced by modern receivers. Measurements results showed that 0 dB conversion loss was realized in the direct-pumped TVTL correlator prototype. A  correlation suppression could also be achieved by the same prototype when comparing the reception of the correlated signal with the reception of the uncorrelated (orthogonal) signal. For the tunable peak amplifier, experiments indicated that the peak gain of the tunable peak amplifier was  with a bandwidth , and the measured frequency tuning range was . The noise figure of the tunable peak amplifier in both simulation and measurement was . Lastly, the tunable peak amplifier also exhibited good linearity in the measurement, which was  in-band  and  out-of-band .

Biography:  Xiating Zou received the B.S. in Electronic Information Engineering from University of Science and Technology of China (USTC), China, in 2016 with the Guo-Moruo Scholarship (the highest honor). She earned her M.S. degree in Electrical and Computer Engineering from UCLA in 2018 and is currently pursuing the Ph.D. degree in Electrical and Computer Engineering at UCLA. During her time at UCLA, she was awarded the UCLA ECE Department Fellowship in 2016 and the Dissertation Year Fellowship in 2020. Her research interests include theory and application of time-varying electromagnetics and design of novel low-noise RF components.

For more information, contact Prof. Yuanxun Ethan Wang (ywang@ee.ucla.edu)

Date/Time:
Date(s) - May 24, 2021
4:00 pm - 6:00 pm

Location:
Via Zoom Only
No location, Los Angeles
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