scholarly journals Full-duplex reflective beamsteering metasurface featuring magnetless nonreciprocal amplification

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sajjad Taravati ◽  
George V. Eleftheriades
Keyword(s):  
Incident Field ◽  
Phase Shifters ◽  
Full Duplex ◽  
Wave Radiation ◽  
Large Wave ◽  
Wave Amplification ◽  
Telecommunication Systems ◽  
Wireless Telecommunication ◽  
A Chain ◽  
Radiation Beams

AbstractNonreciprocal radiation refers to electromagnetic wave radiation in which a structure provides different responses under the change of the direction of the incident field. Modern wireless telecommunication systems demand versatile apparatuses which are capable of full-duplex nonreciprocal wave processing and amplification, especially in the reflective state. To realize such a functionality, we propose an architecture in which a chain of series cascaded radiating patches are integrated with nonreciprocal phase shifters, providing an original and efficient apparatus for full-duplex reflective beamsteering. Such an ultrathin reflective metasurface can provide directive and diverse radiation beams, large wave amplification, steerable beams by simply changing the bias of the gradient active nonmagnetic nonreciprocal phase shifters, and is immune to undesired time harmonics. Having accomplished all these functionalities in the reflective state, the metasurface represents a conspicuous apparatus for efficient, controllable and programmable wave engineering.

scholarly journals Full-duplex Reflective Beamsteering Metasurface Featuring Magnetless Nonreciprocal Amplification

2021 ◽  
Author(s):  
Sajjad Taravati ◽  
George Eleftheriades
Keyword(s):  
Phase Shifters ◽  
Full Duplex ◽  
Wave Radiation ◽  
Large Wave ◽  
Wave Amplification ◽  
Telecommunication Systems ◽  
Wireless Telecommunication ◽  
A Chain ◽  
Different Response ◽  
Radiation Beams

Abstract Nonreciprocal radiation refers to electromagnetic wave radiation in which a structure provides different response under the change of the direction of the incident field. Modern wireless telecommunication systems demand versatile apparatuses which are capable of full-duplex nonreciprocal wave processing and amplification, especially in the reflective state. Here, we propose full-duplex reflective beamsteering metasurfaces for magnetless nonreciprocal wave amplification. To realize such a unique, extraordinary and versatile functionality, we propose a completely new architecture in which a chain of series cascaded radiating patches are integrated with nonreciprocal phase shifters, providing an efficient mechanism for wave reception, signal amplification, nonmagnetic nonreciprocal phase shifting and steerable wave reflection. Having accomplished all these functionalities in the reflective state, the metasurface represents a conspicuous apparatus for efficient, controllable and programmable wave engineering for wireless telecommunications. Such an ultrathin reflective metasurface can provide directive and diverse radiation beams, and steerable beams by simply changing the bias of the gradient active nonmagnetic nonreciprocal phase shifters. The proposed structure provides large wave amplification and is immune to undesired time harmonics, yielding a highly efficient full-duplex reflective beamsteering apparatus.

scholarly journals Frequency Division Multiplexing of Terahertz Waves Realized by Diffractive Optical Elements

2021 ◽  
Vol 11 (14) ◽  
pp. 6246
Author(s):  
Paweł Komorowski ◽  
Patrycja Czerwińska ◽  
Mateusz Kaluza ◽  
Mateusz Surma ◽  
Przemysław Zagrajek ◽  
...  
Keyword(s):  
Frequency Division Multiplexing ◽  
Diffractive Optical Elements ◽  
Frequency Division ◽  
Terahertz Waves ◽  
Optical Elements ◽  
Telecommunication Systems ◽  
Wide Range ◽  
The Future ◽  
Wireless Telecommunication ◽  
Finite Distance

Recently, one of the most commonly discussed applications of terahertz radiation is wireless telecommunication. It is believed that the future 6G systems will utilize this frequency range. Although the exact technology of future telecommunication systems is not yet known, it is certain that methods for increasing their bandwidth should be investigated in advance. In this paper, we present the diffractive optical elements for the frequency division multiplexing of terahertz waves. The structures have been designed as a combination of a binary phase grating and a converging diffractive lens. The grating allows for differentiating the frequencies, while the lens assures separation and focusing at the finite distance. Designed structures have been manufactured from polyamide PA12 using the SLS 3D printer and verified experimentally. Simulations and experimental results are shown for different focal lengths. Moreover, parallel data transmission is shown for two channels of different carrier frequencies propagating in the same optical path. The designed structure allowed for detecting both signals independently without observable crosstalk. The proposed diffractive elements can work in a wide range of terahertz and sub-terahertz frequencies, depending on the design assumptions. Therefore, they can be considered as an appealing solution, regardless of the band finally used by the future telecommunication systems.

Very low frequency electromagnetic phenomena: ‘whistlers’ and micropulsations

1977 ◽  
Vol 279 (963) ◽  
pp. 225-238 ◽  
Keyword(s):  
Low Frequency ◽  
Dynamical Behaviour ◽  
Weddell Sea ◽  
Particle Interactions ◽  
Terrestrial Environment ◽  
Wave Amplification ◽  
A Chain ◽  
Magnetic Conjugacy ◽  
Sea Area ◽  
The Antarctic

Observations of natural electromagnetic phenomena, embracing frequencies ranging from millihertz to tens of kilohertz, have made a major contribution to our knowledge of the terrestrial environment extending out to many Earth’s radii. The Antarctic has offered exceptional opportunities in this field for a number of reasons, including: (i) the location of Antarctic bases (including Halley Bay) at key magnetic latitudes, (ii) magnetic conjugacy to Northern Hemisphere thunderstorm sources, (iii) low interference levels. Important aspects of this research are the investigation of the role of wave-particle interactions in the magnetosphere and that of the structure and dynamical behaviour of the plasmapause, using both passive and active techniques. Comparisons of observations made at antarctic stations and their northern geomagnetic conjugates show close similarities in dominant pulsation periods and demonstrate the uniqueness of the Weddell Sea area in relation to magnetospheric wave amplification at the higher frequencies. An extra dimension to this work is being added, during the International Magnetospheric Study (1976-8), through the development of a chain of stations employing the goniometer (direction-finding) technique pioneered at Halley Bay by Sheffield University.

Ultra-low-power and high-speed SiGe base bipolar transistors for wireless telecommunication systems

1998 ◽  
Vol 45 (6) ◽  
pp. 1287-1294 ◽  
Author(s):  
M. Kondo ◽  
K. Oda ◽  
E. Ohue ◽  
H. Shimamoto ◽  
M. Tanabe ◽  
...  
Keyword(s):  
Low Power ◽  
High Speed ◽  
Bipolar Transistors ◽  
Ultra Low Power ◽  
Telecommunication Systems ◽  
Wireless Telecommunication

scholarly journals Stochastisation of microwave oscillations in microstrip log-periodic antenna-generator with LF noise-like modulation.

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
E.O. Yunevich ◽  
◽  
V.I. Kalinin ◽  
V.D. Kotov ◽  
V.E. Lyubchenko ◽  
...  
Keyword(s):  
Field Effect ◽  
Field Effect Transistors ◽  
Single Frequency ◽  
Power Combining ◽  
Electronic Warfare ◽  
Active Antennas ◽  
Telecommunication Systems ◽  
Wireless Telecommunication ◽  
Effect Transistor ◽  
Oscillator Arrays

Microwave solid-state oscillators of noise-like signals are of the great interest for wireless telecommunication systems, imaging systems and electronic warfare. In the paper, the possibility of power combining in the array of three independent noise-like oscillators is investigated. The noise-like oscillators are based on the microstrip log-periodic antennas which are integrated with field-effect transistors. As an active element, NE350184С field-effect transistor with 13.5 dB gain at 12 GHz is chosen. It was previously shown that single-frequency, multifrequency or noise-like generations are possible in the active antennas. The main factors that affect the generation type are the current in the drain-source circuit of the transistor and the distance between the antenna plane and reflecting screen. It is experimentally shown, that using of the noise-like oscillator arrays makes possible the spectrum and power combining, but the construction is not enough stable and reliable.

scholarly journals Pure and Linear Frequency Converter Temporal Metasurface

2021 ◽  
Author(s):  
Sajjad Taravati ◽  
George V. Eleftheriades
Keyword(s):  
Frequency Conversion ◽  
Frequency Converter ◽  
Temporal Frequency ◽  
Extraordinary Wave ◽  
Phase Shifters ◽  
Linear Frequency ◽  
Telecommunication Systems ◽  
Digitally Controlled ◽  
Field Programmable ◽  
Invisibility Cloaks

Abstract Metasurfaces are ultrathin structures which are constituted by an array of subwavelength scatterers with designable scattering responses. They have opened up unprecedented exciting opportunities for extraordinary wave engineering processes. On the other hand, frequency converters have drawn wide attention due to their vital applications in telecommunication systems, health care devices, radio astronomy, military radars and biological sensing systems. Here, we show that a spurious-free and linear frequency converter metasurface can be realized by leveraging unique properties of engineered transmissive temporal supercells. Such a metasurface is formed by time-modulated supercells; themselves are composed of temporal and static patch resonators and phase shifters. This represents the first frequency converter metasurface possessing large frequency conversion ratio with controllable frequency bands and transmission magnitude. In contrast to conventional nonlinear mixers, the proposed temporal frequency converter offers a linear response. In addition, by taking advantage of the proposed surface-interconnector-phaser-surface (SIPS) architecture, a spurious-free and linear frequency conversion is achievable, where all undesired mixing products are strongly suppressed. The proposed metasurface may be digitally controlled and programmed through a field programmable gate array. This makes the spurious-free and linear frequency converter metasurface a prominent solution for wireless and satellite telecommunication systems, as well as invisibility cloaks and radars. This study opens a way to realize more complicated and enhanced-efficiency spectrum-changing metasurface.

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