RESUMO
The primary bottlenecks in designing and implementing PT-symmetric systems at microwave frequency ranges are noise and instability which can weakly break PT-symmetry resulting in system performance degradation. Practical implementation of such systems and devices require significant level of control and stability and it is crucial to analyze the noise performance of such systems in terms of noise figure and signal-to-noise ratio. We describe and develop a simulation model to calculate noise figure of PT-symmetric system and evaluate the performance degradation. We also discuss application design and circuit configurations that could reduce the noise figure resulting in better performance.
RESUMO
A waveform synthesis technique is introduced and applied to the femtosecond pulse excitation of plasmonic nanoantennas for temporal and spatial energy concentration control. The waveform synthesis process is based on phase and polarization shaping and an understanding of the electromagnetic response of the nanostructure. Linear and radial nano-dipole arrays are analyzed before the log-periodic toothed nanoantenna is investigated as a nanostructure capable of combining the benefits of the nano-dipole arrays. The consistent superiority of the log-periodic toothed nanoantenna is established by comparing its electromagnetic response to that of the radial nano-dipole array using a variety of synthesized excitation waveforms.
RESUMO
In recent years, the study of generating and detecting localized surface plasmons (LSPs) has been expanded from the optical regime to microwave regime. In this Letter, the compact spoof LSPs are introduced through both numerical simulations and near-field measurements. It is observed that the compact LSP structure could effectively reduce the resonant frequency with a stronger resonance strength (GdBsm) and a higher Q-factor. Both electric near-field and surface-current distributions are monitored to examine the resonance processes of the LSP particle.
