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This paper presents a building block approach for the design of frequency identification receivers. The devices are based on a Reconfigurable Discriminator (RD) for frequency measurement, operating from 1 to 4 GHz. The RD is a two-port device used to identify the frequency of an unknown signal. The devices use RF switches, which are implemented with PIN diodes to select different bits used for frequency identification. ; Grant number : Part of this work has been supported by the Generalitat de Catalunya under grant 2014 SGR 1551 and Spanish government projects TEC2014-58341-C4-4-R and PIB2010BZ-00585 (NANOWAVE) © 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

Several civil and military applications (hertzian beams, satellite communications, automotive radars, high resolution imaging systems) require antennas with reconfigurable beam capabilities (beam-scanning, beamshaping, multiple beam generation). Transmitarray antennas are good candidates and represent an alternative to classical phased arrays or reflect-arrays for these applications. The main objective of this thesis is to demonstrate the feasibility of reconfigurable transmitarrays fabricated with standard technologies in Ka-band (20-30 GHz). Different unit-cell designs based on p-i-n diodes have been developed to work in linear and circular polarization. Their optimization and experimental characterization have been performed. Waveguide measurements show insertion losses of 1.09 dB at 29.0 GHz with a 3-dB bandwidth of 14.7%. A hybrid simulation technique has been developed in order to analyze efficiently large transmitarrays in which the sequential rotation technique has been applied to optimize the polarization quality and the radiation patterns. A 400-elements transmitarray operating in circular polarization has been realized and tested in anechoic chamber. A beam-scanning angular coverage of ±60° and circular polarization selection (left/right) have been demonstrated. ; De nombreuses applications civiles et militaires (faisceaux hertziens, futurs réseaux mobiles, communications par satellite, radars automobiles, systèmes d'imagerie haute résolution) nécessitent des antennes à faisceau reconfigurable (dépointage de faisceau, faisceaux multiples, faisceaux formés). Les antennes à réseaux transmetteurs apparaissent comme une alternative aux réseaux phasés classiques ou aux réseaux réflecteurs pour ces applications. L'objectif principal de cette thèse est de démontrer la faisabilité de réseaux reconfigurables fabriqués avec des technologies standards en bande Ka (20-30 GHz). Divers cellules élémentaires utilisant des diodes p-i-n et fonctionnant en polarisation linéaire ou circulaire ont été conçues, optimisées ...

Several civil and military applications (hertzian beams, satellite communications, automotive radars, high resolution imaging systems) require antennas with reconfigurable beam capabilities (beam-scanning, beamshaping, multiple beam generation). Transmitarray antennas are good candidates and represent an alternative to classical phased arrays or reflect-arrays for these applications. The main objective of this thesis is to demonstrate the feasibility of reconfigurable transmitarrays fabricated with standard technologies in Ka-band (20-30 GHz). Different unit-cell designs based on p-i-n diodes have been developed to work in linear and circular polarization. Their optimization and experimental characterization have been performed. Waveguide measurements show insertion losses of 1.09 dB at 29.0 GHz with a 3-dB bandwidth of 14.7%. A hybrid simulation technique has been developed in order to analyze efficiently large transmitarrays in which the sequential rotation technique has been applied to optimize the polarization quality and the radiation patterns. A 400-elements transmitarray operating in circular polarization has been realized and tested in anechoic chamber. A beam-scanning angular coverage of ±60° and circular polarization selection (left/right) have been demonstrated. ; De nombreuses applications civiles et militaires (faisceaux hertziens, futurs réseaux mobiles, communications par satellite, radars automobiles, systèmes d'imagerie haute résolution) nécessitent des antennes à faisceau reconfigurable (dépointage de faisceau, faisceaux multiples, faisceaux formés). Les antennes à réseaux transmetteurs apparaissent comme une alternative aux réseaux phasés classiques ou aux réseaux réflecteurs pour ces applications. L'objectif principal de cette thèse est de démontrer la faisabilité de réseaux reconfigurables fabriqués avec des technologies standards en bande Ka (20-30 GHz). Divers cellules élémentaires utilisant des diodes p-i-n et fonctionnant en polarisation linéaire ou circulaire ont été conçues, optimisées et caractérisées. Les mesures en guide d'onde montrent des pertes minimales de 1,09 dB à 29,0 GHz et une bande passante à 3 dB de 14,7%. Une méthode de simulation hybride a été développée afin d'analyser efficacement des réseaux de grandes dimensions utilisant des rotations séquentielles d'éléments pour optimiser la qualité de polarisation et les diagrammes de rayonnement. Un réseau de 400 cellules élémentaires fonctionnant en polarisation circulaire a été réalisé et testé en chambre anéchoïque. Un dépointage électronique de ±60° et la possibilité de commuter entre les deux polarisations circulaires (droite/gauche) ont été démontrés.

In this paper, we propose Electronically REconfigurable Superstrate (ERES) antenna design to provide simple, yet effective, beam steering capabilities to increase connectivity between wireless sensor network (WSN) nodes. The proposed design involves the superstrate layer concept, proposed originally to increase gain of microstrip patch antennas. By grouping parasitic patches within the designed superstrate layer and introducing a switching circuit with PIN diodes, it has been possible to create sections that can be steered using only 4 digital input output ports. Simulation results indicate, that, by shortening each section independently to the ground, it is possible to steer the main antenna beam electronically. In consequence, the proposed antenna can successfully be used to improve connectivity in WSN nodes relying on inexpensive transceivers and operating in demanding industrial conditions. Acknowledgement: This paper is a result of the Productive4.0 project (https://productive40.eu) which has received funding from the ECSEL Joint Undertaking (JU) under grant agreement No 737459. The Joint Undertaking receives support from the European Union's Horizon 2020 research and innovation programme and Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Luxembourg, Netherlands, Norway, Poland, Portugal, Spain, Sweden, Turkey. The document reflects only the authors' view and the Commission is not responsible for any use that may be made of the information it contains.

[EN] This paper deals with the problem of formally defining and specifying Mission Plans for Remotely Piloted Aircraft Systems (RPAS). Firstly, the profile of RPAS missions is highly variable and different from those of commercial flights. Route variability from the planned route is frequent due to operating conditions and, especially, contingencies. For this reason, RPAS Mission Plans should be reconfigurable: they should allow the nominal plan to be modified during flight time. Secondly, aviation authorities may require the ability to operate in an autonomous mode in response to Command and Control (C2) link losses. As a result, RPAS Mission Plans should specify all possible routings and behaviors in greater detail. The Reconfigurable Mission Plan concept introduced in this paper expands on current flight plans by providing a level of description that improves predictability and allows for reconfiguration, contingency handling, and higher levels of automation and pilot assistance. The paper presents a detailed discussion of RPAS contingency handling and develops a formal specification of the Reconfigurable Mission Plan concept. The paper also develops algorithms for dynamically configuring Mission Plan routes that might mitigate the effect of contingencies. Finally, the whole proposal is validated with a prototype implementation and a proof of concept. ; This work was supported by the Spanish Regional Government Generalitat Valenciana under contract ACIF/2016/197. ; Usach Molina, H.; Vila Carbó, JA. (2020). Reconfigurable Mission Plans for RPAS. Aerospace Science and Technology. 96:1-20. https://doi.org/10.1016/j.ast.2019.105528 ; S ; 1 ; 20 ; 96

This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. As such, it is in the public domain, and under the provisions of Title 17, United States Code, Section 105, may not be copyrighted. ; Proceedings of the 9th International Workshop on Boolean Problems, Freiberg, Germany, Sept. 16-17, 2010, pp. 1-12 (Invited paper) (Unrefereed) ; "Bent Boolean functions are important in the encoding/decoding of secure messages. Because they are the most nonlinear of all functions, they are the least susceptible to linear attack. However, bent functions are rare and difficult to discover. The only known way to enumerate all bent functions is by a sieve in which many prospective functions are tested. This is a tutorial description of the process of bent Boolean function discovery by a reconfigurable computer. Specifically, we discuss the use of SRC Computersâ SRC-6 reconfigurable computer in sieving through a large number of functions. We show why this process is much faster than on a conventional computer (up to 60,000 times), and we discuss the circular pipeline as a method to improve the throughput even further. The circular pipeline takes advantage of the fact that most functions pass not even one test for bentness. The improvement in throughput due to the circular pipeline depends on the relationship between distances among functions, but it is approximately 500 times better than our present throughput. "

This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. As such, it is in the public domain, and under the provisions of Title 17, United States Code, Section 105, may not be copyrighted. ; Proceedings of the 10th International Workshop on Boolean Problems, Freiberg, Germany, Sept. 19-21, 2012, pp. 225-232, 2011 ; Algebraic immunity (Al) is a property of a Boolean function f that measures its susceptibility to an alebraic attack. If f has a low algebraic immunity and f is used in an encryption protocol, then there are ways to successfully cyrptanalyze the system. As a result, it is important to have an efficient means to compute the alebraic immunity of Boolean functions. Unfortunately, algebraic immunity is one of the most complex cryptographic properties to compute. For example, it is significantly more difficult to compute than nonlinearity. Here, we show the advantage of a reconfigurable computer in computating a function's algebraic immunity. For example, we show that a reconfigurable computer is 4.9 times faster than a conventional computer in this computation for 5-variable computer is 4.9 times fater than a conventional computer in this computation for 5-variable functions. Indeed, we compute the distribution of functions to algebraic immunity for all 5-variable functions, a computation that has not been previously accomplished. Interestingly, the problem we address is to design a logic circuit that computes a characteristic of a logic function.

Pattern reconfigurable antennas have aroused intensive research recently because of their critical role in wireless communication and military applications. Phased arrays offer best beam steering ability but they are balky and costly built. Alternatively, cost effective solutions can be achieved by introducing switch circuitry into simpler antenna structures like ring antennas, slot antennas, and spiral antennas. This thesis focuses on single arm rectangular spiral antennas capable to steer the beam by switches attached on the spiral. Two novel beam steering spiral antennas operating at 3.3 GHz with wide beam coverage have been proposed. Simulation was conducted using Ansys HFSS. RF-MEMS varactors or PIN diodes are used as switches. Simulation results show wider azimuth plane coverage than existed designs because of the added bridges and extra switches. The location of the bridges and PIN diodes are determined by parametric sweep simulation process which has been detailed. In order to validate the simulation results, two antennas are fabricated using Rogers 4350 substrate and PIN diodes. They are center fed by SMA connectors with inner pin connecting the starting point of the spiral. Up to three DC biasing signals of both positive and negative voltages are required to achieve various cases for the switches. Since DC supplies are directly connected with spiral arm, biasing line, pad, and quarter wavelength stubs are needed to open circuit RF signals. Although the geometry and locations of them have been optimized, analysis indicates that these elements for biasing purposes generate errors and disagreements from simulation results. The wire connecting DC supply and range errors lead to discrepancy between simulation and measurement. Simulation and measured results for reflection coefficient, radiation pattern (both RHCP and LHCP), gain, and axial ratio are compared. Measurement methods by spinning source, two-orthogonal-cut, and cavity backed circular spiral antennas are detailed. In addition, a thorough review of ...

With the emerging democratization of space, Earth Observation (EO) imagery is becoming increasingly important to a variety of industries. However, it remains difficult and expensive to build constellations that achieve continuous and high-quality global coverage. Reconfiguring a satellite constellation into different orbital planes to change its observational performance is traditionally a fuel intensive procedure. The concept of a reconfigurable constellation (ReCon) accounts for J2 perturbation effects when making fuel efficient maneuvers to shift a satellite's ground track. ReCon reduces the cost of high revisit frequency, high-quality resolution, EO constellations compared to nonreconfigurable constellations by reducing the number of satellites required to achieve repeated observations of a given ground event on demand. This paper first explores the sensitivities of ReCon's performance against uncertainties in reconfiguration demand, design costs, and imagery value. The sensitivity analysis reveals that in cases of extremely low demand, ReCon fails to provide a cost-effective solution in terms of events responded to per dollar spent. In cases of high demand ReCon fails to meet demand altogether. A Monte Carlo analysis over a range of demand scenarios shows using a staged deployment for ReCon offers a flexible, cost-effective solution to the uncertainties in the demand of EO imagery. Deferring launch costs to the future, through a staged deployment, not only provides flexibility in constellation design, but also allows the designer to capitalize on the continuation of lowering launch costs and increasing launch opportunities. Staging the deployment of constellations also allows for the satellites' technology to evolve over time, facilitating the capture of higher value imagery and further enhancing the capabilities of ReCon. Implementing the option to deploy additional satellites in stages makes ReCon significantly better equipped to respond to the uncertainty in the demand of space assets.