There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Thank you very much for downloading computational methods for electromagnetics. Maybe you have knowledge that, people have search numerous times for their favorite readings like this computational methods for electromagnetics, but end up in malicious downloads. Rather than enjoying a good book with a cup of tea in the afternoon, instead they juggled with some malicious bugs inside their laptop. computational methods for electromagnetics is available in our digital library an online access to it is set as public so you can download it instantly. Our books collection hosts in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Kindly say, the computational methods for electromagnetics is universally compatible with any devices to read.

Computational Methods For Electromagnetics

Ultra-high sensitivity sensor has significant application for micro-nano optical devices in terahertz. Here, we propose a simple graphene metasurface, which can achieve obvious graphene plasmon-induced transparency (PIT) phenomenon. We can find that PIT, reflectivity, and absorbance can be effectively tuned by the Fermi level. Moreover, the finite-different time-domain (FDTD) numerical results are well agreement with the coupled mode theory (CMT) results. Interestingly, an ultra-high sensitivity sensor performance based on tunable PIT in terahertz bands can be realized in our proposed metasurface, the sensitivity and Figure of merit (FOM) can reach up to 1.7745 THz/RIU and 23.61, respectively. Hence, these results can provide theoretical guidance for terahertz dynamic integrated photonic devices.

Graphene-based metasurface sensing applications in terahertz band

In this work, we present an efficient polarization conversion device via using a hollow graphene metasurface. The platform can simultaneously realize a series of excellent performances, including the broadband x-to-y cross polarization conversion (CPC) function with near unity polarization conversion ratio (PCR), dual-frequency linear-to-circular polarization conversion (LTC-PC) function, and highly sensitive polarization conversion function manipulation under wide oblique incidence angle range. For instance, the proposed device obtains an x-to-y CPC function with the bandwidth up to 1.83 THz (χPCR ≥98.8%). Moreover, the x-to-y CPC function can be switched to LTC-PC function via artificially tuning the Fermi energy of graphene. The maximal frequency shift sensitivity (S) of polarization conversion function reaches 23.09 THz/eV, suggesting a frequency shift of 2.309 THz for the LTC-PC function when the chemical potential is changed by 0.1 eV. Based on these superior performances, the polarization converter can hold potential applications in integrated and compact devices, such as polarization sensor, switches and other optical polarization control components.

Multi-functional polarization conversion manipulation via graphene-based metasurface reflectors.

Quad-Band Transmissive Metasurface with Linear to Dual-Circular Polarization Conversion Simultaneously

Performance Improvement of a Graphene Patch Antenna using Metasurface for THz Applications

This article reports a graphene-based metasurface to work at terahertz domain as a wideband tunable absorber along with a property of electromagnetic transmittivity. This indeed for the first time claims the widest possible absorption band produced by a graphene metasurface-based rasorber operating in terahertz frequencies (2.24–4.67 THz). Each unit cell comprises stacked graphene, silicon dioxide, and slotted gold layer featuring 99.9% absorptivity as well as 34.01% transmittivity across the respective bands. The other novel feature lies in its ultrathin characteristics ( $\lambda _{\mathrm {g}}$ /10.70), which is improved by more than a factor of 4 relative to its closest competitor, and also in the compactness in periodicity ( $\lambda _{\mathrm {g}}$ /12.49), which is identically improved by a factor of 6. The design is executed using an extensive analysis of simulated results. The lack of experimental facility at those frequencies accessible to the authors in their country has been compensated by verifying the simulated prediction using a circuit model developed inhouse. A new biasing scheme for achieving tunable absorption has been illustrated. This work also promises some features, i.e., polarization-insensitive transmission and absorption together with angularly stable characteristics of the incident wave up to 40°. The proposed structure should find potential applications in terahertz, including communication security, satellite communication systems, and stealth applications.

Graphene-Based Metasurface for Tunable Absorption and Transmission Characteristics in the Near Mid-Infrared Region

https://iopscience.iop.org/article/10.1088/2053-1591/ab2220/pdf

Comment on: 'Wide incidence angle and polarization insensitive dual broad-band metamaterial absorber based on concentric split and continuous rings resonator structure'

In this paper a modified compact CPW fed printed monopole antenna is presented. Modified double circular shaped monopole antennas with different type of feedings are proposed to achieve directional radiation characteristics and high front to back lobe ratio (F/B) for various applications. The proposed antenna covers the ultra-wideband (3.3 GHz–10.6 GHz) and a part of the license free super wideband (10.6 GHz–20 GHz) and it can be used to meet the vast range of wireless applications. For different directional radiation characteristics the proposed antenna can be used for some specific applications such as terrestrial communication like satcom applications, biomedical applications like tumor detection, imaging applications, stroke diagnosis system, and point to point communication etc. The proposed antenna prototypes exhibit good impedance matching for the proposed band of operation. The parametric study is performed to achieve the optimized performance of the antenna. The overall antenna size of the proposed antenna is 42×50×1.57 mm3. The proposed prototypes are designed and simulated using HFSS. The finally designed antenna offers good impedance bandwidth, well directive radiation characteristics, good gain and efficiency.

Printed monopole antenna for UWB and SWB with directional radiation characteristics and high F/B ratio

A terahertz (THz) bandpass filter has been presented in this manuscript based on frequency selective surfaces (FSS). The presented structure is very simple in nature with compact design comprising various rectangular metallic patches, showing a bandpass characteristic in THz region lying between 8.1 THz and 32.1 THz. The structural design along with the evolution of the geometrical shape of the unit cell has been discussed. The 3-dB bandwidth of 23.9 THz has been achieved with referred to center frequency of 20.1 THz. The structure provides ultra-thin nature and can be used for spectroscopy and imaging applications in infrared domain.

Sambit Kumar Ghosh

Papers

Performance Improvement of a Graphene Patch Antenna using Metasurface for THz Applications

Graphene-Based Metasurface for Tunable Absorption and Transmission Characteristics in the Near Mid-Infrared Region

Comment on: 'Wide incidence angle and polarization insensitive dual broad-band metamaterial absorber based on concentric split and continuous rings resonator structure'

Printed monopole antenna for UWB and SWB with directional radiation characteristics and high F/B ratio

An Ultra-thin FSS Bandpass Filter in Terahertz Region