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Conformal leaky-wave antennas for terahertz wireless links
No full textWe explore the performance of curved leaky-wave antennas in the terahertz range. We identify two distinct regimes in whichthe far-field emission pattern varies relative to that of a planar antenna. We show that a curved multi-aperture leaky-waveantenna can be used for agile far-field beam forming, and demonstrate high-gain wireless links at gigabit-per-second data ratewith low bit error rate, in multiple directions simultaneously. This work lays the foundation for the implementation of terahertzleaky-wave structures in conformal geometries
Riesz-projection based simulation and analysis of resonant photonic devices and machine-learning based parameter optimization
No full textWe present Riesz projection based methods relying on contour integration for efficiently computing quasi-normal modes and modal expansions of near-field and far-field physical quantities. We use a finite-element method based implementation of these methods for the analysis of nanophotonic resonators for quantumoptics applications. We use Bayesian optimization methods for finding best geometry parameters yielding, e.g., resonators with maximized quality factor
Electromagnetic Skyrmions of Free Space
No full textIn this talk we overview recent progress in toroidal electrodynamics including generation and detection of toroidal pulses, the study of their space-time “entanglement†and isodiffraction behaviour and light-matter interactions involving anapoles. We will report on the unique supertoroidal pulses, propagating skyrmionic formations of electromagnetic fields that can be non-diffracting and exhibit superoscillatory behavior
Engineering Highly Directive Optical Waveguide Antennas
No full textWe show the numerical and experimental realization of broadband optical traveling-wave antennas made from low-loss dielectric materials which exhibit highly directive patterns. The high directivity is a result of the interplay between two dominant TE- and leaky-modes present in the antenna director. These antennas possess near unity radiation efficiency at the operational wavelength of 780nm, maintaining a broad bandwidth. We envision that our all-dielectric approach demonstrates a new class of antennas that are excellent candidates for optical-communication and sensing
Novel resonant-tunneling-diode terahertz oscillators and applications
No full textThe recent progress in resonant-tunneling diode (RTD) THz oscillators and applications is reviewed. For high-frequency and high output power, RTD oscillators integrated with cylindrical and rectangular cavities have been developed. Structure simplified RTD oscillators for easy device fabrication and good uniformity were proposed and fabricated. This simple structure has an extensibility for large-scale array, active metamaterial, and beam forming function. Novel THz radar systems using RTD oscillators were proposed, and a precise distance measurement and a three-dimensional imaging were demonstrated
Polarization Reconfigurable Patch Antenna with Ground Slots for Sub-6GHz Applications
No full textA polarization reconfigurable patch antenna truncated at the corners has been presented in this paper. The proposed antenna is covering the sub-6GHz band. In order to achieve reconfigurability, D-shaped slots have been cut in the ground plane and two PIN diodes are inserted in each slot. The antenna is capable of switching between two polarization states i.e. linear polarization and circular polarization. Moreover, 3D radiation pattern of the design is also shown in order to check the pattern stability
Convergence acceleration for the numerical solution of Maxwell's equations by processing edge singularities of the electromagnetic field
No full textThe methodology for accelerating the convergence of numerical methods for solving Maxwell's equations in the frequency domain by taking into account the behavior of the electromagnetic field near the geometric edges of wedge-shaped structures is presented. Several algorithms for incorporating treatment of singularities into methods for solving Maxwell's equations in two-dimensional structures by the examples of the analytical modal method and the spectral element method are discussed
Recent Advances in Conformal Transmitarrays
No full textThis talk will give an overview of research on conformal transmitarrays conducted in University of Technology Sydney, Australia. More specifically, it includes our latest progress in high efficiency conformal transmitarrays and multi-beam conformal transmitarrays
Limits on Electromagnetic Scattering
No full textWhile improvements in nanofabrication and computational methods have driven dramatic progress in expanding the range of achievable optical characteristics, they have also greatly increased design complexity. These developments have led to heightened relevance for the study of fundamental limits on optical response. Here, we review recent progress in our understanding of these limits with special focus on an emerging theoretical framework that combines computational optimization with conservation laws to yield physical limits capturing all relevant wave effects
Gap Waveguide Technology using Periodic Structures with Higher Symmetries
No full textIn this work, the use of holes instead of pins for the implementation of the groove version is presented. The periodic structure based on the use of holes requires the glide symmetrical disposition of the unit cell to provide a complete and wide stopband for the parallel plate modes. Design guidelines for this version will be detailed and the advantages in terms of manufacturing will be discussed together with the limitations when compared to the use of pins. Some examples of designed antennas and components in the millimeter wave band using this approach will be presented in the talk