scholarly journals Ultra-Wide Band and Multifunctional Polarization Converter Based on Dielectric Metamaterial

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3857 ◽  
Author(s):  
Ju Gao ◽  
Yiming Zhang ◽  
Yang Sun ◽  
Qiang Wu
Keyword(s):  
Communication Systems ◽  
Wide Band ◽  
Ultra Wide Band ◽  
Transformation Theory ◽  
Polarization Converter ◽  
Frequency Bands ◽  
Polarization Control ◽  
Narrow Bandwidth ◽  
Linearly Polarized ◽  
Low Permittivity

Polarization has always been an important issue in modern communication systems, especially in sensitive measurements. Conventional polarization converters show limited applications due to their large size and narrow bandwidth. In this paper, we demonstrate an ultra-wide band, multifunctional, and highly efficient metamaterial-based polarization converter that is capable of converting a linearly polarized wave into its cross-polarized wave and circularly polarized wave over different frequency bands. The design principle is based on the field transformation theory and the anisotropic plate is made with high/low permittivity strip metamaterials. The simulation results show that the metamaterial-based polarization converter is able to achieve linear-to-linear conversion over 11.5–12.6 GHz, and linear-to-circular conversion over two frequency bands, 3.0–11.5 GHz and 12.6–17.0 GHz, with an average polarization conversion efficiency over 90%. The polarization converter proposed in this paper provides an important stepping stone for future communication systems’ polarization control and can also be extended to higher frequency bands.

A Dual-Channel 6b 1GS/s 0.18um CMOS ADC for Ultra Wide-Band Communication Systems

2006 ◽  
Author(s):  
Young-Jae Cho ◽  
Kyung-Hoon Lee ◽  
Hee-Cheol Choi ◽  
Young-Ju Kim ◽  
Kyoung-Jun Moon ◽  
...  
Keyword(s):  
Communication Systems ◽  
Wide Band ◽  
Ultra Wide Band ◽  
Dual Channel

scholarly journals Microstrip-fed cusp antenna for ultra-wide band communication systems

2009 ◽  
Vol 19 (1) ◽  
pp. 33-38 ◽  
Author(s):  
Ezzeldin A. Soliman ◽  
Walter De Raedt ◽  
Guy A. E. Vandenbosch
Keyword(s):  
Communication Systems ◽  
Wide Band ◽  
Ultra Wide Band

scholarly journals FAST early pulsar discoveries: Effelsberg follow-up

2021 ◽  
Author(s):  
M Cruces ◽  
D J Champion ◽  
D Li ◽  
M Kramer ◽  
W W Zhu ◽  
...  
Keyword(s):  
Electron Density ◽  
Radio Telescope ◽  
White Dwarf ◽  
Wide Band ◽  
Mass Function ◽  
Ultra Wide Band ◽  
Linearly Polarized ◽  
Drift Scan ◽  
L Band

Abstract We report the follow-up of 10 pulsars discovered by the Five-hundred-meter Aperture Spherical radio-Telescope (FAST) during its commissioning. The pulsars were discovered at a frequency of 500-MHz using the ultra-wide-band (UWB) receiver in drift-scan mode, as part of the Commensal Radio Astronomy FAST Survey (CRAFTS). We carried out the timing campaign with the 100-m Effelsberg radio-telescope at L-band around 1.36 GHz. Along with 11 FAST pulsars previously reported, FAST seems to be uncovering a population of older pulsars, bordering and/or even across the pulsar death-lines. We report here two sources with notable characteristics. PSR J1951+4724 is a young and energetic pulsar with nearly 100 per cent of linearly polarized flux density and visible up to an observing frequency of 8 GHz. PSR J2338+4818, a mildly recycled pulsar in a 95.2-d orbit with a Carbon-Oxygen white dwarf (WD) companion of $\gtrsim 1\, \rm {M}_{\odot }$, based on estimates from the mass function. This system is the widest WD binary with the most massive companion known to-date. Conspicuous discrepancy was found between estimations based on NE2001 and YMW16 electron density models, which can be attributed to under-representation of pulsars in the sky region between Galactic longitudes 70○ < l < 100○. This work represents one of the early CRAFTS results, which start to show potential to substantially enrich the pulsar sample and refine the Galactic electron density model.

scholarly journals High-Efficiency Asymmetric Transmission of Red-Near-Infrared Light Based on Chiral Metamaterial

2021 ◽  
Vol 9 ◽  
Author(s):  
Yu Tian ◽  
Zhiwei Chen ◽  
Fang-Fang Ren ◽  
Qingguo Du ◽  
Zhengying Li
Keyword(s):  
Communication Systems ◽  
High Efficiency ◽  
Polarized Light ◽  
Infrared Light ◽  
Polarization Conversion ◽  
Metamaterial Structure ◽  
Polarization Converter ◽  
Asymmetric Transmission ◽  
Linearly Polarized ◽  
Chiral Metamaterial

Designing and fabricating high-performance polarization converters that exhibit asymmetric transmission (AT), for light with different circularly/linearly polarized states with opposite propagating directions, are in high demand. The AT phenomenon leads to potential applications as isolators and circulators in information and communication systems. We propose a chiral metamaterial structure with high AT efficiency for two types of linearly orthogonal polarized red-near-IR light in two opposite incident directions. Theoretical results showed that the proposed chiral metamaterial structure achieves cross-polarization conversion where the polarization conversion ratio (PCR) is over 90%, in a broadband wavelength range from 715 to 810 nm, for both forward-propagating linearly polarized light and backward-propagating orthogonal linearly polarized light. The physical mechanisms of the polarization converter with the AT have been investigated. It was confirmed that the Fabry–Perot-like resonance and coupling between electric and magnetic dipoles lead to highly efficient asymmetric polarization conversion for two orthogonal linearly polarized light. Additionally, the conversion efficiency and bandwidth of the polarization converter are successfully optimized by adjusting the related structure parameters.

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