Afterwards, the rules of Interval Arithmetic are exploited to compute the bounds of deviation in the resonance frequency of each element, the phase response of the element and the radiated power pattern. Different techniques are proposed and assessed in order to eliminate the dependency effect such as reformulating the interval function and the Enumerative interval analysis. Moreover, the Minkowski sum approach is used to eliminate the wrapping effect.
Design and optimization of reflectarray antennas Italian abstract: In questa tesi si presentano pertanto nuovi tipi di elementi re-irradianti per il progetto dei reflectarray.
In seguito sono state sviluppate versioni modificate del BOA e del cGA, versioni che hanno mostrato prestazioni ampiamente migliori rispetto agli algoritmi originali.
La singola cella ha mostrato caratteristiche che la rendono adatta per il progetto di un intera RRA. Reflectarray antennas are nowadays a quite popular technology, used in several applications, thanks to their advance features e. Reflectarray antenna thesis, they still suffer for some limitations that are partially due to their intrinsic reduced bandwidth, that could be enlarged, but generally with a drastic increase of the structure complexity.
Therefore, in this thesis new types of re-radiating element for reflectarray design will be presented.
Moreover, the design will exploit the capability of optimization algorithms to support the design of RAs and enhance their bandwidth. The developed activity was mainly focused on the following two research areas: For what concerns the activity on the optimization algorithms, different available solutions, including evolutionary algorithms e.
Modified versions of BOA and cGA, which greatly improved their performances with respect to the original algorithms, have been then developed. These modified algorithms have been successfully applied to array synthesis problems, as the design of thinned arrays and sparse arrays, revealing promising features also for more complex applications as the optimized design of reflectarray antennas.
Passive reflectarrays are flat arrays of passive printed elements, whose resonant behavior allows a phase shaping of a beam incident on the array, thus replacing the curvature of a conventional reflector.
Despite of their advantages, RAs present also some drawbacks, the main of which is their narrow bandwidth. In order to enhance the bandwidth, new possible configurations of reflectarray unit elements have been studied.
After an exhaustive analysis of different types of elements, the most promising have been used to design entire RAs; their full-wave numerical analysis shows the obtained bandwidth improvement. Reconfigurable reflectarray antennas RRAs have been also investigated in the thesis.
RRA offer the possibility of dynamically control and reconfigure the antenna's beam patterns, feature which is highly demanded in radar and satellite communication applications.
The selected configuration shows its characteristics that make it suitable for the design of a whole RRA.Reconfigurable Reflectarray Antenna Desi gn using Anisotropic Dielectric Materials. It is possible to vary the dielectric permittivity of anisotropic liquid crystals simply by applying a dc bias voltage across the substrate, which allows the molecules of anisotropic.
This thesis first describes an automated test system developed for a unit of the Space Flight Laboratory’s Modular Power System, the Micro-Switched Power Node. This unit is responsible Table Transparent conducting oxide reflectarray antenna payload – driving requirements.
patterns of the antenna are measured and compared with the simulations. It has been shown that the reflectarray is capable of beam switching to 35° in Ka band, 24° in K band. Keywords: Reflectarray, RF MEMS switches, Reconfigurable antennas, Split-ring, Dual band antennas. Reflectarray (RA) antennas are introduced as an alternative to the conventional parabolic reflectors and antenna arrays.
Therefore, two attractive antenna concepts are studied here, namely micromachined Fabry-Perot (FP) cavity antennas and folded reflectarray antennas. In this thesis works, we have designed a novel configuration of micromachined FP cavity antennas using silicon membrane and bulk micromachining techniques in W band. Reflectarray (RA) antennas are introduced as an alternative to the conventional parabolic reflectors and antenna arrays. The RA provides the advantages of both reflectors and arrays. The narrow bandwidth is one of the distinct disadvantages of RA. The RA bandwidth is primarily limited by two factors, the element bandwidth, and the spatial phase delay. BEAM-STEERABLE AND RECONFIGURABLE REFLECTARRAY ANTENNAS FOR HIGH GAIN SPACE APPLICATIONS by KALYAN K. KARNATI ph-vs.com Jawaharlal Technological University, India, M.S. University of Central Florida, U.S.A, A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
The RA provides the advantages of both reflectors and arrays. The narrow bandwidth is one of the distinct disadvantages of RA. The RA bandwidth is primarily limited by two factors, the element bandwidth, and the spatial phase delay.
patterns of the antenna are measured and compared with the simulations.
It has been shown that the reflectarray is capable of beam switching to 35° in Ka band, 24° in K band. Keywords: Reflectarray, RF MEMS switches, Reconfigurable antennas, . Hello all, I am doing a thesis project on reflectarray antennas.
I am modeling in CST I have a question concerning the setup. 1) Which solver do you use, i have created a model of a reflectarray with a PEC-backed substrate with a couple of patches on top and a horn exactly 1 F/D away.