Communications in Physics

A Design of high efficiency and wideband dual-functional metasurface for polarization conversion and asymmetric transmission

Hoa Nguyen Thi Quynh — 2024-10-29

A wideband and high-efficiency bi-functional metasurface for polarization conversion and asymmetric transmission (AT) based on the gratings/ polarization converter/gratings structure is proposed. The proposed metasurface structure consists of a two double-split ring structure array sandwiched by two orthogonal metallic sub-wavelength gratings. Using two orthogonal metallic
sub-wavelength gratings, the proposed metasurface reveals excellent AT effect and nearly perfect polarization conversion performance for linearly polarized waves. The proposed metasurface achieves a polarization conversion ratio (PCR) of above 0.99 from 3.7 GHz to 20.2 GHz with a relative bandwidth (RBW) of 138% and an AT parameter of over 0.9 from 5.8 GHz to 17 GHz with
an RBW of 99.5%. Moreover, the proposed metamaterial maintains high PCR and AT performance for a wide range of incident angles. Due to its excellent features, such as the wideband and high efficiency of both PCR and AT performances, the proposed bi-functional metasurface can be useful for promising applications such as polarization imaging. radar, radiometer, and transmission.
array antennas.

New Physics in the 3-3-1 models

Hoang Ngoc Long — 2024-08-30

Two main ingredients of current particle physics such as local gauge symmetry and mass generation via the Higgs mechanism being basic ground of the Standard Model are widely confirmed by experimental data. However, some problems such as neutrino masses, dark matter, baryon asymmetry of Universe have clearly indicated that the Standard Model cannot be the ultimate theory of nature. To surpass the mentioned puzzles, many extensions of the Standard Model (called beyond Standard Model) have been proposed. Among beyond Standard Models, the 3-3-1 models have some intriguing features and they get wide attention. The pioneer models develop in some directions. In this paper, new main versions of the 3-3-1 models and their consequences are presented.

Multiple mobility edges in quasi-periodic mosaic lattices revisited: A numerical study based on time-dependent reflection

Phi Ba Nguyen — 2024-09-05

The dynamics of a short wave packet in one-dimensional quasi-periodic lattices with mosaic modulated on-site potentials is investigated numerically. This model is characterized by the modulation period $\kappa$ and the quasi-periodic potential strength $\lambda$. For parabolic wave packets with a given central energy $E_{0}$, we calculate the averaged time-dependent reflectance, $\langle R(t) \rangle$, for various values of $\kappa$ and $\lambda$. From the extensive numerical calculations, we show that there exist multiple mobility edges in such a model with the number of mobility edges to be always equal to $2(\kappa-1)$.