A Large-Signal Model of Ferroelectric Thin-Film Transmission Lines

作者：Rocas Eduard^*; Collado Carlos; Mateu Jordi; Orloff Nathan; O'Callaghan Juan M; Booth James C

来源：IEEE Transactions on Microwave Theory and Techniques, 2011, 59(12): 3059-3067.

DOI：10.1109/TMTT.2011.2169420

• Circuit modeling
• ferroelectric films
• large-signal model
• microwave measurements
• nonlinear response
• thermal effects

This paper evaluates the microwave nonlinear properties and tuning at RF frequencies of ferroelectric Ba0.3Sr0.7TiO3 thin films by on-wafer measurements of the second-and third-order harmonics and intermodulation products of several coplanar transmission lines as a function of dc bias. We analyze these data by use of a large-signal circuit model to obtain the nonlinear distributed capacitance as a function of voltage.
Whereas the model with an electric-field-dependent dielectric constant for the ferroelectric material is able to predict the tuning when a dc voltage is applied and the generated harmonics, it disagrees with the measured third-order intermodulation products at frequencies 2 omega(1) - omega(2) and 2 omega(2) - omega(1). Nonlinear effects due to self-heating mechanisms are also considered, along with an additional phenomenological source of nonlinearities, to model all the observables. Interactions between the ferroelectric and self-heating components give rise to a deep null in both the measured and modeled intermodulation-distortion component.

• 出版日期2011-12