Topic: Reflectarray Antenna Thesis – 551071 | Sweet Enuff

The third part of the thesis is dedicated to the detailed study of different phasing technique for the realization of reconfigurable microstrip antennas for steerable reflectarray applications.

Reflectarray Antenna Thesis Paper – 370424 – 1 …

Reconfigurable reflectarray antennas (RRAs) have been also investigated in the thesis.
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Reflectarray Antenna Thesis Paper

Ageneralized analysis approach is presented and the radiation performanceof reflectarray antennas on singly-curved conformal cylindricalplatforms are studied and compared with their planar counterpart.

Discussione: Reflectarray Antenna Thesis – 644771

The objective of the thesis is to establish the physical layer foundations of the ultra-broadband communication in the THz band. First, a unified multi-path propagation channel is modeled in the THz band, based on ray-tracing techniques. The wideband characteriza- tion are analyzed, which include the distance-varying spectral windows, the delay spread, the wideband capacity and the temporal broadening effects. Second, a multi-wideband waveform design for the THz band is proposed to improve the distance and support ultra- high-speed transmissions. Third, two algorithms for timing acquisition in the pulse-based wireless systems are developed, namely the low-sampling-rate (LSR) algorithm, and the maximum likelihood (ML)-based approach. Fourth, the distance-aware bandwidth resource allocation schemes for the single-user and multi-user THz band networks are developed. Fifth, a three-dimensional (3-D) end-to-end model is developed and characterized, which includes the responses of the graphene-based reflectarray antenna and the 3-D multi-path propagation.

It isrevealed that conformal reflectarray antennas are a suitable choice fora high-gain antenna where curved platforms are required.
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Multi-band reflectarray antennas in Ku and THz …

Modern communication systems require intelligent antenna arrays to achieve increased phase range for the performance improvement. Moreover the design requirements of spacecraft antennas for satellite communications and telecommunication missions require multifunction antennas to prevent the propagation of electromagnetic waves in certain frequency bands. This project investigates the feasibility of employing reflectarray antenna integrated with FSS textured configurations to combat the scan blindness problem. Performance investigation of different strategic resonant elements has been carried out in X-band frequency range by using commercially available computer models of CST MWS and Ansoft HFSS based on Finite Integral Method (FIM) and Finite Element Method (FEM) respectively. Frequency Selective characteristics are also exploited by embedding the dipole, square loop and triangular loop resonant elements on top of the groundless substrate. Integrated FSS Reflectarray (FSS-RA) configurations based on iterative loop length approach are than implemented for operation in both X and Ku-band to improve the static phase range for the reduction of phase errors resulting in scan blindness. It has been demonstrated that the maximum static phase range of 540° can be obtained with the loop length variation of 6.8mm. Moreover novel algorithms based on mathematical models have been developed for the calculation of progressive phase distribution depicted by each individual resonant element and resonant frequency estimation of FSS reflectarrays. In order to validate the authenticity of numerical results waveguide scattering parameter measurements have been carried out by fabricating two patch unit cells for each reflectarray resonant element. Measured results demonstrated that reduction in reflection area of resonant elements from 105.74mm2 to 7.33mm2 tends to increase the reflection loss values from 2.63dB to 20.25dB. Moreover, an increased measured static phase range of 290° offering the reduction in phase errors is also shown by employing the triangular loop element.

Design and optimization of reflectarray antennas - …

La presente ricerca si è focalizzata soprattutto su due obiettivi:- Lo sviluppo di tecniche di ottimizzazione avanzate- Lo studio di innovative Antenne Reflectarray (RA), stampabili e a banda larga Per quel che concerne gli algoritmi di ottimizzazione, in un primo tempo sono state prese in considerazione diverse soluzioni possibili, in particolare algoritmi evolutivi come:PSO, GA, Bayesian Optimization Algorithm (BOA) e Compact Genetic Algorithm (cGA).

Reconfigurable Printed Reflectarray Antenna for LEO ..

(in lingua inglese)

Le antenne Reflectarray costituiscono oggi una tecnologia piuttosto popolare, usata in svariati contesti e applicazioni grazie alle loro caratteristiche avanzate come il basso costo, la distribuzione conforme e la riconfigurabilità. Nonostante tutto, le antenne Reflectarray soffrono tutt’ora di alcune limitazioni dovute in parte alla loro larghezza di banda intrisicamente ridotta, banda che può essere allargata ma a costo di un drastico aumento della complessità della struttura. In questa tesi si presentano pertanto nuovi tipi di elementi re-irradianti per il progetto dei reflectarray. In particolare, per la definizione delle RAs e per aumentare la loro banda passante si sfrutteranno le potenzialità di specifici algoritmi di ottimizzazione.