Physically Oriented Design of Negative Capacitors Based on Linvill’s Floating Impedance Converter

Buiantuev, Bair; Kalmykov, Nikita; Kholodnyak, Dmitry; Brizić, Ante; Vincelj, Leo; Hrabar, Silvio

doi:10.1109/tmtt.2021.3131544

Cited by 14 publications

(1 citation statement)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alternatively, compensation through the structure of the evaluated network is also possible. Because hardware adaptations by impedance converters [37], [38] would be associated with high additional costs, the problem of parasitic capacitances is to be improved by adapted signal processing within the scope of this work. Figure 11 demonstrates that even not fully accurate corrections, such as those from Equation 1, can give useful results in EIT.…”

Section: Discussionmentioning

confidence: 99%

Open Source Sensor Interface for Soft Detectors in Surgical Simulators

et al. 2023

View full text Add to dashboard Cite

Surgical simulation is an emerging area of research and development, making new developments of especially hybrid simulators highly relevant. In this context, soft sensors enable low-cost position or force detection in haptically realistic synthetic tissue imitations to link the physical and virtual components of a patient phantom. To accelerate and facilitate the development of such simulators, an open-source sensor interface module optimized for use with soft carbon black silicone composite based sensors is presented. The module can measure complex voltages and impedances between multiple measurement channels at various frequencies. This enables up to three-dimensional tool tracking of conductive surgical instruments in patient phantoms as well as force or deformation detection at relevant structures. Several application scenarios are presented. Disruptive influences on the sensors are minimized by evaluating the signals based on discrete Fourier transform. Higher frequency signal coupling avoids contacting problems with soft sensors, which are often highly piezoresistive. Compensation functions or favorable sensor structures can largely avoid the influence of parasitic capacitances, which are particularly prevalent in low-cost electronics. The universally applicable module provides all the necessary electronics, including firmware and software interface for the subsequent processing computer. The handy module offers 17 measuring channels as well as digital inputs and outputs and is operated via USB. In addition to the evaluability of various sensor types relevant for surgical simulation, electroimpedance tomography is also supported, as demonstrated by the examples.

show abstract

Section: Discussionmentioning

confidence: 99%

Open Source Sensor Interface for Soft Detectors in Surgical Simulators

et al. 2023

View full text Add to dashboard Cite

show abstract

Non-Foster approach to broadband optical metamaterials based on Lorentzian gain materials

Hrabar,

Ziolkowski

2024

Applied Physics Letters

View full text Add to dashboard Cite

All passive metamaterials are inherently narrowband due to fundamental dispersion-energy constraints, and their dispersive properties are usually approximated by a Lorentz model. However, there are broadband active metamaterials in the radio frequency (RF) regime based on negative capacitors with non-Foster dispersion properties. Non-Foster dispersion is usually considered as an “electronic-engineering trick” that cannot be applied at optical frequencies. Here, we demonstrate that the dispersion relation of a RF non-Foster capacitor is similar to that of an optical gain material described by a Lorentz model. This insight paves the way to realize non-Foster optical metamaterial structures. As the simplest example, we develop a broadband non-Foster optical epsilon-near-zero slab with a 1:10 bandwidth.

show abstract