Practical Design of Filters Using EBG Waveguides Periodically Loaded with Metal Ridges

[EN] The dispersion diagram of infinite periodic structures is useful for the practical design of waveguide filters. Starting from the dispersion diagram of a unit cell, it is possible to generate a finite structure with very similar pass- and stop-bands (gaps). However, truncation of the infinite periodic structure degrades the pass-band performance. In this paper, these impairments are overcome by means of suitable waveguide tapers matching the impedance of the periodic structure to the access ports. As a result, the design of practical low-pass filters, derived from passive structures based on Electromagnetic Band-Gap (EBG) waveguides periodically loaded with metal ridges, is successfully addressed. According to this procedure, a five-order and an eight-order EBG low-pass filters are obtained after an optimization step. Measurements of a manufactured prototype fully validate the proposed approach.This work was supported by the Ministerio de Economía y Competitividad (MINECO), Spanish Government, under the R&D projects TEC2013-47037-C5-1-R and TEC2013-47037-C5-4-R. The authors would like to thank ITACA (Instituto de Aplicaciones de las Tecnologías y de las Comunicaciones Avanzadas), from Technical University of Valencia (Valencia, Spain), for their support in the accurate manufacturing of the low-pass filter prototypeMarini, S.; Soto Pacheco, P.; Coves, A.; Gimeno Martinez, B.; Boria Esbert, VE. (2016). Practical Design of Filters Using EBG Waveguides Periodically Loaded with Metal Ridges. Progress in ElectromagneticsResearch C. Pier C. 63:13-21. https://doi.org/10.2528/PIERC15111603S13216

Design of compensated multiport waveguide junctions considering mechanization effects

tA new tool for the rigorous and efficient design of compensated multiport waveguide junctions, consider-ing the mechanization effects due to low-cost manufacture techniques, is presented. Several new designsfor a great variety of key components, present in modern microwave and millimetre-wave equipment, areproposed taking into account the introduction of rounded corners in the rectangular waveguide accessports. The new implemented tool permits to control and compensate for the potential degradation of thewide-band performance of such components prior to their fabrication, thus achieving an optimal design.All the presented results have been successfully validated by comparing the obtained simulated datawith the results provided by a commercial software based on the finite-element method.San Blas Oltra, ÁA.; Boria Esbert, VE.; Gimeno Martinez, B.; Cogollos Borras, S. (2015). Design of compensated multiport waveguide junctions considering mechanization effects. AEU - International Journal of Electronics and Communications. 69(1):328-331. doi:10.1016/j.aeue.2014.10.003S32833169

Long-term multipactor discharge in multicarrier systems

[EN] A new mechanism of long-term multipactor in multicarrier systems is studied employing both analytical and numerical methods. In particular, the investigation is focused on the impact that a realistic secondary emission yield at low energies produces on the development of long term multipactor. A novel analytical model for this interperiod charge accumulation is presented using the traditional multipactor theory for parallel plates, and approximating the multicarrier signal as a single-carrier signal modulated by a pulsed signal envelope. The analytical predictions are verified by numerical simulations for a typical rectangular waveguide. The analytical and numerical results demonstrate that the susceptibility of the system to develop a long-term multipactor discharge increases with higher values of low-energy secondary emission yield.The authors would like to thank ESA/ESTEC for having funded this research activity through the Contract “RF Breakdown in Multicarrier Systems” (19918/06/NL/GLC).Anza Hormigo, S.; Vicente Quiles, CP.; Gimeno Martinez, B.; Boria Esbert, VE.; Armendariz, J. (2007). Long-term multipactor discharge in multicarrier systems. Physics of Plasmas. 14(8):1-8. doi:10.1063/1.2768019S1814

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

EM Based Synthesis and Design of Bandpass Waveguide Filters Including Manufacturing Effects with FEST3D

This article aims at the industry interest on automated design tools that are able to take into account manufacturing effects. First, an efficient design strategy for bandpass waveguide filters including the rounded corners arising from low-cost manufacturing procedures is presented. This technique is based on a recent enhanced prototype and synthesis methodology able to consider the real structure parts. Using the resulting electromagnetic (EM)-based synthesis technique, an excellent structure is extracted, which requires, at most, only a slight final EM optimization. Second, this article presents analytical expressions providing error estimates for the different filter performances in terms of manufacturing tolerances. From such expressions, designers can determine the tolerance to be requested for a tuning-less implementation. Moreover, they can also be used to set the convergence criterion for the synthesis procedure. A fully automated design tool of bandpass waveguide filters able to consider manufacturing impairments has been developed and integrated in the commercial software Full-wave EM Simulation Tool 3D (FEST 3D)The authors thank Mrs. Eva Tarin, Mr. Oscar Monerris, and Mr. Jaime Armendariz for their work on the integration of the synthesis tool for H-plane waveguide filters in FEST 3D. This work was supported by Ministerio de Educacion y Ciencia, Spanish Government, under the Research Project ref. TEC2010-21520-C04-01.Soto Pacheco, P.; Boria Esbert, VE.; Carceller Candau, C.; Vicente Quiles, CP.; Gil Raga, J.; Gimeno Martinez, B. (2012). EM Based Synthesis and Design of Bandpass Waveguide Filters Including Manufacturing Effects with FEST3D. International Journal of RF and Microwave Computer-Aided Engineering. 22(1):93-103. https://doi.org/10.1002/mmce.2058893103221Reiter, J. M., & Arndt, F. (1995). Rigorous analysis of arbitrarily shaped H- and E-plane discontinuities in rectangular waveguides by a full-wave boundary contour mode-matching method. IEEE Transactions on Microwave Theory and Techniques, 43(4), 796-801. doi:10.1109/22.375226Zhou, J., Duan, B., & Huang, J. (2010). Influence and tuning of tunable screws for microwave filters using least squares support vector regression. International Journal of RF and Microwave Computer-Aided Engineering, 20(4), 422-429. doi:10.1002/mmce.20447Nikolova, N. (2008). Electromagnetic software in microwave engineering [Guest Editorial]. IEEE Microwave Magazine, 9(6), 10-12. doi:10.1109/mmm.2008.929880Boria, V. E., Gimeno, B., Marini, S., Taroncher, M., Cogollos, S., Soto, P., … Gil, J. (2007). Recent advances in modeling, design, and fabrication of microwave filters for space applications. International Journal of RF and Microwave Computer-Aided Engineering, 17(1), 70-76. doi:10.1002/mmce.20199Kozakowski, P., & Mrozowski, M. (2002). Gradient-based optimization of filters using FDTD software. IEEE Microwave and Wireless Components Letters, 12(10), 389-391. doi:10.1109/lmwc.2002.804561Boria, V. E., Bozzi, M., Bruni, F., Cogollos, S., Conciauro, G., Gimeno, B., & Perregrini, L. (2003). Efficient analysis of in-line waveguide filters and frequency-selective surfaces with stepped holes. International Journal of RF and Microwave Computer-Aided Engineering, 13(4), 306-315. doi:10.1002/mmce.10087Morro, J. V., Esteban, H., Boria, V. E., Bachiller, C., & Belenguer, A. (2008). Optimization techniques for the efficient design of low-cost satellite filters considering new light materials. International Journal of RF and Microwave Computer-Aided Engineering, 18(2), 168-175. doi:10.1002/mmce.20264Hunter, I. (2001). Theory and Design of Microwave Filters. doi:10.1049/pbew048eSoto, P., Tarin, E., Boria, V. E., Vicente, C., Gil, J., & Gimeno, B. (2010). Accurate Synthesis and Design of Wideband and Inhomogeneous Inductive Waveguide Filters. IEEE Transactions on Microwave Theory and Techniques, 58(8), 2220-2230. doi:10.1109/tmtt.2010.2052668Morini, A., Venanzoni, G., & Rozzi, T. (2006). A new adaptive prototype for the design of side-coupled coaxial filters with close correspondence to the physical structure. IEEE Transactions on Microwave Theory and Techniques, 54(3), 1146-1153. doi:10.1109/tmtt.2005.864112Morini, A., Venanzoni, G., Farina, M., & Rozzi, T. (2007). Modified Adaptive Prototype Inclusive of the External Couplings for the Design of Coaxial Filters. IEEE Transactions on Microwave Theory and Techniques, 55(9), 1905-1911. doi:10.1109/tmtt.2007.904329Cogollos, S., Marini, S., Boria, V. E., Soto, P., Vidal, A., Esteban, H., … Gimeno, B. (2003). Efficient modal analysis of arbitrarily shaped waveguides composed of linear, circular, and elliptical arcs using the BI-RME method. IEEE Transactions on Microwave Theory and Techniques, 51(12), 2378-2390. doi:10.1109/tmtt.2003.819776Levy, R. (1967). Theory of Direct-Coupled-Cavity Filters. IEEE Transactions on Microwave Theory and Techniques, 15(6), 340-348. doi:10.1109/tmtt.1967.1126471Balasubramanian, R., & Pramanick, P. (1999). Computer aided design ofH-plane tapered corrugated waveguide bandpass filters. International Journal of RF and Microwave Computer-Aided Engineering, 9(1), 14-21. doi:10.1002/(sici)1099-047x(199901)9:13.0.co;2-

Bovine enzootic haematuria from consumption of Pteris deflexa and Pteris plumula in northwestern Argentina

Bovine enzootic haematuria (BEH) is caused by prolonged ingestion of toxic principles of bracken fern, essentiallybyPteridium spp. In northwestern Argentina, this disease has a greateconomic impact ant it is attributed a chronic consumption to Pteridium arachnoideum. This paper describes two endemic areas for enzootic hematuria due to the consumption of Pteris deflexa and Pteris plumula. Two areas where P. deflexa and P. plumula are endemic, but free of Pteridium species, were devised and seven farms were visited. The disease was confirmed basedon the presence of clinicallyaffected animals. Infournecropsies bleeding neoplastic lesions were observed in the mucosa of the urinary bladder. At phytochemical analysis, both ptaquiloside and pterosin B were found in P. deflexa and P. plumula. Thus, the consumption of P. deflexa and P. plumula can also cause BEH.EEA SaltaFil: Micheloud, Juan Francisco. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Animal del Chaco Semiárido. Área de investigación en Salud Animal -EEA Salta; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Colque Caro, Luis Adrian. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Martinez, Olga Gladys. Universidad Nacional de Salta. Faculta de Ciencias Naturales. Museo de Ciencias Naturales. Herbario; ArgentinaFil: Gimeno, Eduardo Juan. Universidad Nacional de La Plata, Facultad de Ciencias Veterinarias; ArgentinaFil: Ribeiro, Debora De Silva Freitas. Universidad Federal de Minas Gerais. Escola de Veterinaria. Departamento de Clínica e Cirugia Veterinarias; BrasilFil: Soto Blanco, Benito. Universidad Federal de Minas Gerais. Escola de Veterinaria. Departamento de Clínica e Cirugia Veterinarias; Brasi

Efficient Design of Waveguide Manifold Multiplexers Based on Low-Order EM Distributed Models

In this paper, a new systematic technique to design manifold-coupled multiplexers in waveguide technology is proposed. The new technique uses generalized low-order electromagnetic (EM) distributed models, which constitute a half-way point between the fast, but imprecise, analytical models, and the more accurate, but costly, full-wave EM models. The method can be applied to contiguous and noncontiguous channel multiplexers, in both E-plane or H-plane configurations. This paper covers the complete design procedure for manifold multiplexers, starting from the required specifications and finishing with the physical dimensions. After explaining the general design technique for multiplexers with channel filters based on transmission-line resonators, the method is specialized for the design of classic multiplexers with circular-waveguide dual-mode filters. As a further application example, the same methodology is also used for the design of a nonconventional tuningless wideband multiplexer with a new type of rectangular waveguide filters. This paper is concluded with a comparison between simulation and measurements for the wideband multiplexer. Excellent agreement between measurements and simulations are demonstrated, thereby validating the complete design procedure.The authors would like to thank the European Space Agency (ESA) and Val Space Consortium (VSC) High Power RF Space Laboratory (A laboratory funded by the European Regional Development Fund, A way of making Europe) for financing the manufacture and experimental validation of the wideband six-channel PIM test bed.Cogollos Borras, S.; Soto Pacheco, P.; Boria Esbert, VE.; Guglielmi, M.; Brumos Vicente, M.; Gimeno Martinez, B.; Raboso García-Baquero, D. (2015). Efficient Design of Waveguide Manifold Multiplexers Based on Low-Order EM Distributed Models. IEEE Transactions on Microwave Theory and Techniques. 63(8):2540-2549. doi:10.1109/TMTT.2015.2442990S2540254963

Multipactor susceptibility charts for ridge and multiridge waveguides

“© 2012 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 aim of this paper is to study the multipactor radio-frequency breakdown voltage in several ridge and multiridge waveguide configurations. First, multipactor susceptibility charts for several types of ridged waveguides have been computed using the commercial software FEST3D. Next, these charts have been used to predict multipactor threshold values for a bandpass filter and a quasi-low-pass filter both containing ridge waveguide sections. Furthermore, multipactor simulations using FEST3D are carried out to calculate the multipactor threshold of the aforementioned structures. A good agreement between predictions and simulations has been found for both filter examples.Gonzalez Iglesias, D.; Soto Pacheco, P.; Anza Hormigo, S.; Gimeno Martinez, B.; Boria Esbert, VE.; Vicente Quiles, CP.; Gil Raga, J. (2012). Multipactor susceptibility charts for ridge and multiridge waveguides. IEEE Transactions on Electron Devices. 59(12):3601-3607. doi:10.1109/TED.2012.2215611S36013607591

Electron Emission of Pt: Experimental Study and Comparison With Models in the Multipactor Energy Range

"(c) 2016 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."Experimental data of secondary emission yield (SEY) and electron emission spectra of Pt under electron irradiation for normal incidence and primary energies lower than 1 keV are presented. Several relevant magnitudes, as total SEY, elastic backscattering probability, secondary emission spectrum, and backscattering coefficient, are given for different primary energies. These magnitudes are compared with theoretical or semiempiricalThis work was supported in part by the Ministerio de Economia y Competitividad under Project TEC2013-47037-C5-4-R, and in part by MICIIN through the Space Programme under Project AYA2012-39832-C02-01/02. The review of this paper was arranged by Editor M. Thumm.Bronchalo, E.; Coves, A.; Mata Sanz, R.; Gimeno Martinez, B.; Montero, I.; Galán, L.; Boria Esbert, VE.... (2016). Electron Emission of Pt: Experimental Study and Comparison With Models in the Multipactor Energy Range. IEEE Transactions on Electron Devices. 63(8):3270-3277. https://doi.org/10.1109/TED.2016.2580199S3270327763

Optimized Multipactor-Resistant Wedge-Shaped Waveguide Bandpass Filters

[EN] Wedge-shaped waveguides present a certain advantage with respect to rectangular waveguides regarding their resistance to multipactor discharges. In this paper, the optimal configuration for the wedge geometry is investigated based on theoretical results, on a precise multipactor prediction tool, and on previous experience. In addition, design rules are presented, which allow us to achieve for wedge-shaped filters electrical performances comparable to the ones of rectangular waveguide filters, while at the same time improving the multipactor-free power range. As a proof of concept, two three-pole bandpass filters with equivalent electrical characteristic of 150-MHz bandwidth, centered at 12 GHz (Ku band), and the same Q factor have been designed, manufactured, and tested. The first design is based on conventional rectangular waveguide technology, while the second one has non-parallel broadside walls (wedge-shaped cross section). The multipactor power threshold and RF performance of the filters have been measured in order to validate the improvements achievable employing wedge-shaped resonators.This work was supported by the Ministerio de Ciencia e Innovacion, Spain, under Research Project TEC2010-21520-C04-01/TCM.Hueso González, J.; Raboso García-Baquero, D.; Ernst, C.; Schmitt, D.; Boria Esbert, VE.; Gimeno Martinez, B.; Taroncher Calduch, M.... (2013). Optimized Multipactor-Resistant Wedge-Shaped Waveguide Bandpass Filters. IEEE TRANSACTIONS ON PLASMA SCIENCE. 41(8):2135-2144. https://doi.org/10.1109/TPS.2013.2253134S2135214441