Síntesis y diseño de filtros paso bajo

[ES] Técnica mejorada de síntesis y diseño de filtos paso bajo en guía rectangular. Con ésta se consigue aumentar las prestaciones de los filtros en terminos de manejo de potencias, tamaño y peso.[EN] Improvements in the low pass filters synthesis and design procedure. Using this procedure there are big improvements in terms of power handling, size and weight.Monerris Belda, Ó. (2010). Síntesis y diseño de filtros paso bajo. http://hdl.handle.net/10251/27440.Archivo delegad

Automatic, Calibrated and Accurate Measurement of S-Parameters in Climatic Chamber

When measuring RF or microwave devices under a temperature profile inside a climatic chamber, one of the main problems lies in the impossibility to have the network analyzer calibrated for all the temperatures measured along the profile. Typically, the calibration is performed just at room temperature, assuming that there is going to be an error in the rest of the measured temperatures. That error will be higher the further we are from room conditions. In this work, we present a systematic procedure for accurately measuring the S-parameters of a device at different temperatures. It applies a calibration algorithm using the S-parameters of the device under test (DUT) and of the calibration standards measured at the different temperatures of interest along the temperature profile.This work was supported by the European High RF Power Space Laboratory of Val Space Consortium for contributing with its installations - Laboratory co-funded by the European Regional Development Fund-A way of making Europe.Monerris Belda, Ó.; Díaz Caballero, E.; Ruiz Garnica, J.; Boria Esbert, VE. (2015). Automatic, Calibrated and Accurate Measurement of S-Parameters in Climatic Chamber. IEEE Microwave and Wireless Components Letters. 25(6):412-414. doi:10.1109/LMWC.2015.2421330S41241425

Experimental Analysis of the Multipactor Effect With RF Pulsed Signals

© 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.The main goal of this letter is the analysis of the multipactor effect within a coaxial waveguide excited by an RF pulsed signal. The variation of the multipactor RF voltage thresholdwiththe ON interval length of the pulse has been analyzed. To reach this aim, an in-house multipactor simulation code based on the Monte-Carlo algorithm has been implemented. The numerical simulations show that the multipactor RF voltage threshold increases as the ON pulse interval diminishes. In addition, an experiment was carried out to validate the proposed theoretical model, and demonstrating the excellent agreement between the theory and the experimental data. Finally, the results are compared with the 20-gap-crossing rule used in the space standard document (ECSS-E20-1A).The work of O. Monerris Belda was supported by the European Regional Development Fund. The review of this letter was arranged by Editor A. Ortiz-Conde.Gonzalez Iglesias, D.; Monerris Belda, Ó.; Diaz, M.; Gimeno Martinez, B.; Boria Esbert, VE.; Raboso García-Baquero, D. (2015). Experimental Analysis of the Multipactor Effect With RF Pulsed Signals. IEEE Electron Device Letters. 36(10):1085-1087. doi:10.1109/LED.2015.2468068S10851087361

Novel multipactor studies in RF satellite payloads: Single-carrier digital modulated signals and ferrite materials

In this work it is reviewed the most novel advances in the multipactor RF breakdown risk assessment devoted to RF satellite microwave passive devices employed in space telecommunication systems. On one side, it is studied the effect of transmitting a single-carrier digital modulated signal in the multipactor RF voltage threshold in a coaxial line. On the other hand, an analysis of the multipactor phenomenon in a parallel-plate waveguide containing a magnetized ferrite slab it is presented

Multipactor Threshold Estimation Techniques Based on Circuit Models, Electromagnetic Fields and Particle Simulators

[EN] Multipactor has become a keylimiting factor of the final performance of satellite communication systems, due to the increase in power levels and/or operating frequency bands. As a result, the critical components of these systems must meet demanding multipactor specifications which should be considered during the design process. This paper describes the different techniques available to predict the multipactor threshold power for radio frequency (RF) and microwave passive hardware under continuous wave (CW) excitation, from cumbersome particle simulations to fast approximate methods based on circuit models. All these techniques have been described and compared together for the first time, including also a detailed description of the configuration issues of commercial particle simulators required to obtain accurate multipactor threshold predictions. The techniques are applied to both wideband and narrowband application examples. The predictions have been compared with measured thresholds of manufactured samples obtained with a novel multipactor test bed, thus allowing to highlight the advantages and limitations of each technique and particle simulator. From this paper, it will be possible to choose the most suitable procedure (and an appropriate simulator, if needed) to obtain multipactor threshold prediction of passive hardware.The work of Pablo González was supported by the FPU Fellowship of the Ministerio de Educación, Cultura y Deporte, Spanish Government, with Ref. FPU17/02901. This work was supported in part by the Ministerio de Ciencia e Innovación (MICIN, Spanish Government) under R&D Project PID2019-103982RB-C41 (funded by MICIN/AEI/10.13039/501100011033), and in part by the European Space Agency (ESA) under Project H2020-ESA-007 (funded by the European Union's Horizon 2020 Research and Innovation Program).González-Santatecla, P.; Alcaide, C.; Cervera, R.; Rodríguez, M.; Monerris, Ó.; Petit, J.; Rodríguez Pérez, AM.... (2022). Multipactor Threshold Estimation Techniques Based on Circuit Models, Electromagnetic Fields and Particle Simulators. IEEE Journal of Microwaves. 2(1):57-77. https://doi.org/10.1109/JMW.2021.313228457772

Advanced Techniques for Multipactor Testing

[ES] En los últimos años han proliferado los nuevos sistemas de satélites, sobre todo las grandes constelaciones en las órbitas terrestres bajas. Casi todos los satélites transmiten señales digitales con diversas modulaciones y niveles de potencia. Y no sólo eso, el modelo de negocio exige un rápido despliegue de los satélites, lo que impone enormes restricciones a los proveedores de equipos de carga útil de microondas. Un área de riesgo clave para estos equipos sigue siendo la avería del multipactor bajo niveles de potencia de moderados a altos. Debido a la aleatoriedad inherente al fenómeno multipactor, los clientes tienden a añadir márgenes de diseño adicionales para los componentes de microondas de alta potencia. Esto se traduce en costes más elevados, dispositivos más voluminosos y más tiempo para las pruebas. A partir de la experiencia personal realizando ensayos de multipactor, la principal motivación del trabajo descrito en la tesis ha sido emprender una revisión exhaustiva de este fenómeno y desarrollar capacidades de ensayo multipactor de vanguardia. Proporcionar medios para la prueba rápida de multipactores bajo una variedad de señales moduladas de banda ancha. La tesis demuestra que las modulaciones analógicas y digitales tienen un impacto significativo en el umbral multipactor. También se analizan los regímenes multipactor a corto y largo plazo, regímenes que, en algunos casos, presentan umbrales multipactor muy diferentes para el mismo hueco crítico. La necesidad de reducir el peso de la carga útil de microondas convierte a la multiportadora en una excelente opción para los diseñadores. Al encaminar varias señales a través del mismo dispositivo, el peso de la carga útil se reduce drásticamente. Las soluciones comerciales para pruebas multicarrier no son adecuadas debido a los altos niveles de potencia requeridos. Se presentan varias estrategias para implementar bancos de pruebas multiportadora con parámetros controlables. Los resultados demuestran que la señal generada es precisa y estable en el tiempo. Por último, se propone un novedoso sistema de detección de multipactores para hacer frente a la detección de multipactores cuando se utilizan señales moduladas y multiportadora de cualquier ancho de banda. Este método tiene la misma sensibilidad que el conocido anulador de microondas para señales de onda continua y la supera para señales moduladas. El procesamiento digital de señales utilizado para detectar los patrones multipactor proporciona un método de detección totalmente autónomo.[CA] En els darrers anys han proliferat els nous sistemes de satèl·lits, sobretot les grans constel·lacions a les òrbites terrestres baixes. Gairebé tots els satèl·lits transmetten dades digitals amb diverses modulacions i nivells de potència. I no només això, el model de negoci exigeix un ràpid desplegament dels satèl·lits, cosa que imposa enormes restriccions als proveïdors de càrrega útil de microones. Una àrea de risc clau per a aquests equips continua sent la descarrega de multipactor sota nivells de potència de moderats a alts. A causa de l'aleatorietat inherent al fenomen multipactor, els clients tendeixen a afegir marges de disseny addicionals per als components de microones d'alta potència. Això es tradueix en costos més elevats, dispositius més voluminosos i més temps per a les proves. A partir de l'experiència personal realitzant assajos de multipactor, la motivació principal del treball descrit a la tesi ha estat emprendre una revisió exhaustiva d'aquest fenomen i desenvolupar capacitats d'assaig multipactor d'avantguarda. Proporcionar mitjans per a la prova ràpida de multipactors sota una varietat de senyals modulats de banda ampla. La tesi demostra que les modulacions analògiques i digitals tenen un impacte significatiu al llindar multipactor. També s'analitzen els règims multipactor a curt i llarg termini, règims que, en alguns casos, presenten llindars multipactor molt diferents per al buit crític mateix. La necessitat de reduir el pes de la càrrega útil de microones fa de la transmissií multiportadora en una excel·lent opció per als dissenyadors. Encaminant diverses senyals a través del mateix dispositiu, el pes de la càrrega útil es redueix dràsticament. Les solucions comercials per a proves multicarrier no són adequades a causa dels alts nivells de potència requerits. Es presenten diverses estratègies per implementar bancs de proves multiportadora amb paràmetres controlables. Els resultats demostren que el senyal amb què s'alimenta el dispositiu sotmès a proves és precís i estable en el temps. Finalment, es proposa un nou sistema de detecció de multipactors per fer front a la detecció de multipactors quan s'utilitzen senyals modulats i multiportadors de qualsevol amplada de banda. Aquest mètode té la mateixa sensibilitat que el conegut anul·lador de microones per a senyals d'ona contínua i la supera per a senyals modulats. El processament digital de senyals utilitzat per detectar els patrons multiactor proporciona un mètode de detecció totalment autònom.[EN] In the recent past, there has been a proliferation of new satellite systems, especially the large constellations in the Low Earth Orbits (LEOs). Nearly all satellites now carry digital traffic with a variety of modulations and power levels. Not only that, the business model requires rapid deployment of satellites, putting enormous constraints for the suppliers of microwave payload hardware. A key risk area for such equipment remains the multipactor breakdown under moderate to high power levels. Owing to the inherent randomness of the multipactor phenomenon, customers tend to add extra design margins for the high power microwave components. This results in higher costs, bulkier devices and longer time for testing. Based on personal experience in multipactor testing, the prime motivator for the work described in the thesis has been to undertake a comprehensive review of this phenomenon and develop cutting edge multipactor test capabilities, providing means for the rapid multipactor testing under a variety of wide-band modulated signals. The thesis dissertation shows that analog and digital modulations have a significant impact in the multipactor threshold. The short and long-term multipactor regimes are also analyzed, regimes that, in some cases, have very different multipactor thresholds for the same critical gap. The need to reduce the microwave payload weight by using multicarriers in a single transponder provides an excellent option for designers. By routing several signals through the same device, the payload weight is dramatically reduced. Commercial solutions for multicarrier testing are not suitable because of the high power levels required. Several strategies to implement multipactor test benches with controllable parameters are presented. Results prove that the signal being fed to the device under tests is accurate and stable over time. Finally, a novel multipactor detection system is proposed to cope with multipactor detection when modulated and multicarrier signals of any bandwidth are used. This method has the same sensitivity as the well known microwave nulling for continuous wave signals and surpasses it for modulated signals. The digital signal processing used to detect the multipactor patterns provides a full autonomous detection method.Monerris Belda, Ó. (2023). Advanced Techniques for Multipactor Testing [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/19278

The impact on port competition of the integration of port and inland transport services

The performance of the transport chain is important for the efficiency and competitiveness of an economy. In the context of port competition, there has been an increasing cooperation between firms involved in the intermodal transport chain including seaport services. This paper examines the economic incentives and welfare implications to the integration of port activities with inland transport services under inter-ports competition. Although ports find it advantageous to engage in such integration process it may be detrimental to welfare, since shippers' aggregate surplus decreases - noting that farther away users benefit at the expense of those closer to the ports. Several scenarios not leading to such welfare decrease are identified: asymmetries in port capacities, government regulation and efficiency gains. These latter results provide support to policies that favor integration processes of transport service

A three-stage competition game in an air transport network under asymmetric valuation of flight frequencies

This paper analyzes the effects of changes in aeronautical charges as brought by several airport management regimes on the air transport industry. Airlines compete on both price and non-price variables, where connecting passengers have asymmetric valuations of flight frequencies in different legs. Changes in landing fees trigger airlines reactions on flight frequencies and airfares, whose sign depends on the weight attached to flight frequencies. Thus, an increase in the spoke landing, fee leads to more international flights under low valuations of frequencies at spoke airports. Simulation exercises show that profit-maximizing aeronautical charges only as the spoke airport are preferable to those either only at the hub airport or at both airports. Welfare losses are lower when airports are granted to a unique infrastructure manager rather than to independent ones. When frequencies in the hub are highly valued, profit-maximizing charges only at the spoke airport will likely induce a welfare increase

High-Power Multicarrier Generation for RF Breakdown Testing

(c) 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, 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 components of this work in other works.Testing of satellite components for high RF power breakdown effects, such as multipactor and corona or passive-intermodulation, is a topic of growing interest in the aerospaceindustry. Switching fromthe classical single carrier approach to the more realisticmulticarrier scenario is very challenging from the experimental point of view. Themulticarrier signals, amplifiedby several RF power amplifiers, need to have controlled phase, amplitude, and frequency in each carrier. Fine tuning of the signal generator phases is required in order to compensate the phase drift occurring in the active elements of the test bed. This paper presents an efficient and low-cost technique to generate multicarrier signals, valid for testing vacuum breakdown phenomena in satellite components.This work was supported in part by the European High RF Power Space Laboratory of European Space Agency and Val Space Consortium, Laboratory co-Funded by the European Regional Development Fund and in part by the Ministerio de Economia y Competitividad, Spanish Government, under the Research Project TEC 2013-47037-C5-1-R and Project TEC 2013-47037-C5-4-R. The review of this paper was arranged by Editor L. Kumar.Monerris Belda, Ó.; Díaz Caballero, E.; Boria Esbert, VE.; Gimeno Martinez, B. (2017). High-Power Multicarrier Generation for RF Breakdown Testing. IEEE Transactions on Electron Devices. 64(2):556-563. doi:10.1109/TED.2016.2641243S55656364

Viability of new road infrastructure with heterogeneous users

This paper explores the importance of heterogeneity in value of time and route choice when assessing the viability of new road infrastructure to alleviate congestion problems. The model incorporates strategic interaction between road operators in a cost-benefit framework and several competitive regimes are considered. It is then employed to establish the financial and socio-economic viability of a congestion pricing demonstration entering Madrid city centre, where road users have to choose between a free but highly congested road and a priced free-flowing road (semi-private regime). A logit estimation is undertaken with information from a questionnaire among road users in the Eastern Madrid area to obtain users' value of time and of congestion. The tolls obtained generate a traffic reallocation towards the new roadway such that revenues suffice to render the infrastructure socio-economically viable. The private and the low toll regimes generate similar welfare gains that are close to the first best. Yet the former supposes large losses to users. The low toll and the semi-private regimes do not raise such distributional concerns. However, the low toll regime requires a sufficiently high traffic growth rate to make it financially viable; this does not happen for the other competitive regimes.Parallel road network Heterogenous users Viability