Simultaneous beam steering of multiple signals based on optical wavelength-selective switch

A novel, photonics-based scheme for the independent and simultaneous beam steering of multiple radio frequency signals at a wideband phased-array antenna is presented. As a proof of concept, a wavelength-selective switch (WSS) is employed both as a wavelength router to feed multiple antenna elements and as a tunable phase shifter to independently control the phase of each signal at any antenna element. In the experiment, two signals at 12.5 and 37.5 GHz are simultaneously fed to the four output ports of the WSS with independent and tunable phase shifts, emulating the independent steering of two signals in a four-element phased-array antenna. The results confirm the precision and flexibility of the proposed scheme, which can be realized both with bulk components or resorting to photonic integrated circuits, especially for wide-band applications. The architecture for a possible integrated implementation of the proposed solution is presented, employing a structure based on micro-ring resonator. Starting from these results, the feasibility of an integrated version of the presented architecture is also considered. The proposed photonic integrated circuit realizing the beam-forming network might be based on tunable true-time delay, as well as on phase shift through micro-ring resonators, and could be conveniently implemented with CMOS-compatible silicon technology.</jats:p

Job Placement of JTPA-Trained Welfare Recipients: Implications for the JOBS Program in Southern and Nonmetro States

The new Job Opportunities and Basic Skills Training Program was instituted to provide education, training, and employment for adults receiving Aid to Families with Dependent Children. This study uses job placement rates for AFDC recipients trained through Job Training Partnership Act programs to gauge the difficulty participants in the new program may have in finding jobs. The results indicate that, at minimum, there would have been 56 percent more participants in the new JOBS program than there were in Job Training Partnership Act programs had the JOBS program started in the 1986 program year. Only about 60 percent of the AFDC recipients in JTPA-training programs obtained jobs, suggesting that the larger number of JOBS participants also would have had difficulty finding jobs. Estimates of job vacancies and competition from the unemployed also indicate that JOBS participants would face stiff competition for employment, particularly in Southern and nonmetro states. Lack of training facilities and employment opportunities in many rural areas may make it necessary for AFDC recipients in those areas to move if they want to participate in the new program

Precision Measurement of the Boron to Carbon Flux Ratio in Cosmic Rays from 1.9 GV to 2.6 TV with the Alpha Magnetic Spectrometer on the International Space Station

Knowledge of the rigidity dependence of the boron to carbon flux ratio (B/C) is important in understanding the propagation of cosmic rays. The precise measurement of the B/C ratio from 1.9 GV to 2.6 TV, based on 2.3 million boron and 8.3 million carbon nuclei collected by AMS during the first 5 years of operation, is presented. The detailed variation with rigidity of the B/C spectral index is reported for the first time. The B/C ratio does not show any significant structures in contrast to many cosmic ray models that require such structures at high rigidities. Remarkably, above 65 GV, the B/C ratio is well described by a single power law R[superscript Δ] with index Δ=-0.333±0.014(fit)±0.005(syst), in good agreement with the Kolmogorov theory of turbulence which predicts Δ=-1/3 asymptotically.National Science Foundation (U.S.) (Grants 1455202 and 1551980)Wyle Research (Firm) (Grant 2014/T72497)United States. National Aeronautics and Space Administration (NASA Earth and Space Science Fellowship Grant HELIO15F-0005

Modelling Tunable Integrated Optoelectronic Oscillators

Optoelectronic oscillators (OEOs) are recognized for their ability to generate ultra-low phase noise and high-frequency microwave (MW) signals, surpassing traditional electronic oscillators. Recent research has focused on creating wideband tunable and compact integrated OEOs to minimize size and improve stability, which is essential for applications like instrumentation, adaptive radars, communication transceivers, and phase-locked loops. However, the modeling of OEOs is challenging due to the need for simultaneous simulation of electronic and photonic components. This paper reviews various modeling techniques tailored specifically for OEO configurations. Additionally, it extends existing computer-aided model to explore widely tunable hybrid integrated OEOs using Si3N4 micro-ring resonator (MRR) notch filters, considering practical device parameters and integration platform requirements

Photonics-based tunable 1-50 GHz RF transmitter on silicon chip

The paper presents an innovative tunable software-defined RF transmitter based on integrated photonics, able to work in 1-50GHz with very fast tuning. The system has been characterized and verified in a communication scenario

Estudo da influência da locação de uma edificação rural na carga térmica solar recebida pelas paredes

The purpose of this paper is to verifythe influence of a rural edification orientation on the radiant thermal load (solar radiation) intercepted byit. The authors examined two situations commonlyfound: the North-South and East-West orientations. In order to determine the radiant thermal load, so important in the ventilation and refrigeration problems, it was assumed a model of construction as an example and the proposed relations can be applied to anydesired construction model. The results show that the radiant thermal load from East-West reached 74% of the North-South exposure.O presente trabalho se propõe a verificar de que modo a orientação de uma edificação rural influe na carga térmica radiante (radiação solar) interceptada pela mesma. Duas situações freqüentemente encontradas na prática são examinadas: a orientação Norte-Sul e a Leste-Oeste. Para determinar a carga térmica radiante, de importância nos problemas deventilação e refrigeração, é adotado um modelo de construção a título de exemplo, sendo que as relações aqui propostas são aplicáveis a qualquer modelo de construção desejado. Os resultados mostraram quea carga térmica radiante da exposição Leste-Oeste chega a ser 74% da carga na exposição Norte-Sul

Advancement of photonic integration technology for space applications: A x-band scan-on-receive synthetic aperture radar receiver with electro-photonic beamforming and frequency downconversion capability

Synthetic Aperture Radar is a well-known technique for remote sensing applications with great advantages like uninterrupted imaging capabilities even at night or in presence of cloud cover. However, spaceborne SAR sensors face major challenges such as cost and size, which are among the barriers against their applicability for future constellations of low-Earth observation applications. SAR sensors are not compact and require large or medium-sized satellites, which cost hundreds million dollars. To solve these challenges, the recently started SPACEBEAM project, funded by the European Commission, aims at developing a novel SAR Scan-on-Receive approach, exploiting a hybrid integrated optical beamforming network (iOBFN). The compactness and frequency flexibility of the proposed photonic solution complies with the requirements of future constellations of low-Earth orbit satellites in terms of size, weight, power consumption, and cost (SWaP-C). In the design of the SCORE SAR receiver module, we target the development of an X-band receiver having a large swath width of 50 km (5 times wider than state-of-art spaceborne SAR systems), although at the same time enabling a fine spatial resolution of 1.5 m in both along-track and across-track directions. In this paper, we present specifications and preliminary design of the SCORE-SAR receiver at equipment level, where we aim at the realization of a hermetically packaged hybrid InP/TriPleX™ photonic integrated circuit (PIC) for this application. We target the design for the PIC as well as for the RF front-end and control electronics, enabling the electro-photonic frequency down-conversion of the RF signals and the fast control of iOBFN with &lt;300 ns switching time

Design and Performance Estimation of a Photonic Integrated Beamforming Receiver for Scan-On-Receive Synthetic Aperture Radar

Synthetic aperture radar is a remote sensing technology finding applications in a wide range of fields, especially related to Earth observation. It enables a fine imaging that is crucial in critical activities, like environmental monitoring for natural resource management or disasters prevention. In this picture, the scan-on-receive paradigm allows for enhanced imaging capabilities thanks to wide swath observations at finer azimuthal resolution achieved by beamforming of multiple simultaneous antenna beams. Recently, solutions based on microwave photonics techniques demonstrated the possibility of an efficient implementation of beamforming, overcoming some limitations posed by purely electronic solutions, offering unprecedented flexibility and precision to RF systems. Moreover, photonics-assisted RF beamformers can nowadays be realized as integrated circuits, with reduced size and power consumption with respect to digital beamforming approaches. This paper presents the design analysis and the challenges of the development of a hybrid photonic-integrated circuit as the core element of an X-band scan-on-receive spaceborne synthetic aperture radar. The proposed photonic-integrated circuit synthetizes three simultaneous scanning beams on the received signal, and performs the frequency down-conversion, guaranteeing a compact 15 cm2-form factor, less than 6 W power consumption, and 55 dB of dynamic range. The whole photonics-assisted system is designed for space compliance and meets the target application requirements, representing a step forward toward a deeper penetration of photonics in microwave applications for challenging scenarios, like the observation of the Earth from space

Food consumption behaviours in Europe:Mapping drivers, trends and pathways towards sustainability

Why do European consumers buy food the way they do? Which key factors drive Europeans’ food consumption patterns and how could they be used to create pathways toward sustainability? The VALUMICS project’s evidence-based report provides insights to what influences consumers the most in their food choices. The report ‘Food consumption behaviours in Europe’ brings together data across various countries, such as the United Kingdom, Germany, France and Italy. Through in-depth literature research, focus groups and expert consultations, the report provides a better understanding of the status quo, trends, motivations as well as barriers and opportunities towards more sustainable food consumption behaviours in general. The focus is on five product categories: Beef, dairy, salmon, tomatoes and bread. Findings indicate that food consumption behaviours can be largely attributed to price considerations, family eating habits, health concerns or social contexts of consumers. The report highlights that environmental awareness and values play little to no role in the consumption patterns. “Certain changes can only be made by politics, or the EU in this case, which should impose high sustainability limits and standards: for example, banning disposable plastics is a good start. Until certain management practices are allowed, it is difficult to behave more sustainably because everyone else can be more economically competitive” noted one of the experts interviewed for the report. Other actions suggested in the report include fostering stronger communication channels between producers and consumers, with the potential for increasing the resilience of food value chains as well as using behavioural insights to inform strategies and action plans for more sustainable food consumption. The report ’Food consumption behaviours in Europe’ is the first in a series of VALUMICS publications focusing on analysing food consumption. The upcoming reports look into successful interventions for sustainable food behaviour, multi-stakeholder recommendations toward more sustainable food consumption, and food retailer interventions to support this shift.Nicolau, M., Esquivel, L., Schmidt, I., Fedato, C., Leimann, L., Samoggia, A., Monticone, F., Prete, D.M., Ghelfi, R., Saviolidis, M.N., Olafsdottir, G., Sigurdardottir, H., Aubert, P.M., Huber, E., Aditjandra, A., Hubbard, C., De, A., Gorton, M., Čechura, L., Bogason, G.S., Brimont, L., Odene, J. & Schamari, D. Report on (2021) Food consumption behaviours in Europe. Mapping drivers, trends and pathways towards sustainability. VALUMICS "Understanding Food Value Chains and Network Dynamics", funded by European Union's Horizon 2020 research and innovation programme GA No 727243. Deliverable: D6.1, CSCP, Germany, 87 pages