Sorolla Ayza, Mario

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https://academica-e.unavarra.es/handle/2454/50055

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Sorolla Ayza

First Name

Mario

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Ingeniería Eléctrica y Electrónica

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751225

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484

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Now showing 1 - 10 of 57

Open Access
On the determination of the phase center of gaussian horn antennas
(1998) Río Bocio, Carlos del; Teniente Vallinas, Jorge; Gonzalo García, Ramón; Sorolla Ayza, Mario; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Gaussian horn antenna designs have experimentally demonstrated excellent performance to produce a very pure Gaussian beam mode with extremely low sidelobes and crosspolarization levels. These results make very attractive these antennas for high performance applications as satellite communications, radar and remote sensing. The particular position of the phase center inside the horn antenna is crucial in the subsequent process to design the mirror system to be illuminated by the antenna. The Gaussian horn antennas, because the feature to excite a Gaussian beam modes, have the phase center close to the horn throat instead of the output horn aperture as usual. This feature is particular of Gaussian horn antennas, and it supposes a change in the design process using these antennas. The mathematical determination, by correlation of the output fields with Gaussian structures, and the numerical demonstration, will be showed in this paper. Also, some considerations of the advantages or disadvantages of this property will be commented.
Open Access
Línea de transmisión cuasi-óptica con modos gaussianos de orden superior para sistemas basados en gyrotrones tecnológicos para aplicaciones cerámicas
(1997) Río Bocio, Carlos del; Gonzalo García, Ramón; Möbius, Arnold; Sorolla Ayza, Mario; Thumm, Manfred; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper, a description of a new compact microwave oven system based on a tecnological gyrotron for material processing applications is presented. The whole system has been designed by the Institute of Applied Physics in Nizhny Novgorod (Russia) and nowadays is installed in the Forschungszentrum (Karlsruhe, Germany). It consists ot a technological gyrotron working at 30 GHz giving 10 Kw CW in the TE02 circular waveguide mode, a quasi-optical transmission line (optimized in this work) and the final very oversized cavity or applicator. The original transmission line had a transmission efficiency of about 70%, by using a Vlasov launcher to generate a fundamental gaussian beam from the TE02 mode. The power was driven through a total of three mirrors. The improved design presented here increases the transmission efficiency up to 91%, by using a higher order gaussian beam mode, azimuthaly polarized and conical profile, by using only two ellipsoidal mirrors.
Open Access
Planoconcave lens by negative refraction of stacked subwavelength hole arrays
(Optical Society of America, 2008) Beruete Díaz, Miguel; Navarro Cía, Miguel; Sorolla Ayza, Mario; Campillo, Igor; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
This work presents the design of a planoconcave parabolic negative index metamaterial lens operating at millimeter wavelengths fabricated by using stacked subwavelength hole arrays. A staircase approximation to the ideal parabola profile has been done by removing step by step one lattice in each dimension of the transversal section. Theory predicts power concentration at the focal point of the parabola when the refractive index equals -1. Both simulation and measurement results exhibit an excellent agreement and an asymmetrical focus has been observed. The possibility to design similar planoconcave devices in the terahertz and optical wavelengths could be a reality in the near future.
Open Access
A slow light fishnet-like absorber in the millimeter-wave range
(EMW Publishing, 2011) Navarro Cía, Miguel; Torres Landívar, Víctor; Beruete Díaz, Miguel; Sorolla Ayza, Mario; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
A novel route to achieve a narrowband free-space electromagnetic absorber in any range of the spectrum based on stacked subwavelength hole arrays is proposed. The absorption is obtained by means of a slow light mode inside a fishnet-like engineered structure and exploiting the unavoidable misalignments and bucklings of the free-standing stack. An incoming pulse becomes permanently trapped in the structure due to the near zero group velocity which causes an enhancement of the radiation-structure interaction that leads to a huge increment of losses arising from the finite conductivity of the metal as well as arrangement tolerances. This approach is studied not only by simulation but also experimentally under normal incidence at millimeter wavelengths. Moreover, a basic grasp about the angular dependence of the structure is given by analyzing the 2D dispersion diagram. It shows that this scheme may also display high absorption under oblique incidence for s-polarization (or TE-polarization), whereas p-polarization (TM-polarization) would degrade its performance.
Open Access
Estudio de la posibilidad de utilizar modos de orden superior en guías de onda cuasi-ópticas
(1995) Río Bocio, Carlos del; Gonzalo García, Ramón; Marín Pilz, Miguel; Sorolla Ayza, Mario; Möbius, Arnold; Thumm, Manfred; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
The possibility to employ low power gyrotron tubes (10-30 kW, CW) at millimeter wave frequencies (30-100 GHz) has potential applications in advanced ceramic sintering, surface coating, radar, remote sensing, etc.. In materials processing applications, the final shape of the beam is not relevant, because the experiment have to be done in a cavity which has a metallic mode stirrer in order to obtain inside a uniform distribution of the electromagnetic fields. In this paper, we present a preliminar study, showing that it is possible to use high order modes in the transmission line to carry the power to the final experiment efficiently.
Open Access
Arrangements of via-holes in microstrip lines as metallodielectric periodic structures
(Wiley, 2000) Gómez Laso, Miguel Ángel; Lopetegui Beregaña, José María; Bacaicoa, Miguel; Hernández, Jorge; Gonzalo García, Ramón; Sorolla Ayza, Mario; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Gobierno de Navarra / Nafarroako Gobernua
In this paper, the use of via holes in microstrip lines to design periodic structures that can be regarded as metallodielectric electromagnetic crystals is analyzed. The proposed novel periodic structures achieve a notably increased reflectivity compared to that obtained with a single via hole. Theoretical analysis and experimental results are provided showing a satisfactory performance for these devices as broadband reflectors or short circuits with enhanced behavior at high frequencies.
Open Access
Gaussian beam propagation versus Huygens method in non-paraxial conditions
(1997) Gonzalo García, Ramón; Turullols, Pedro; Río Bocio, Carlos del; Sorolla Ayza, Mario; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper, we present a study about the difference between Gaussian beam propagation and Huygens method to obtain the radiation pattern in the case of non-paraxial conditions. We fix a way to determine the error in the Gaussian beam propagation, in this way, we could know if the approximation is good enough. The computational results show that it is not possible to use the Gaussian propagation equation when we are working with Gaussian beams in non-paraxial conditions.
Open Access
Lentes metálicas basadas en el fenómeno de transmisión extraordinaria para conseguir índices de refracción negativos
(2009) Navarro Cía, Miguel; Beruete Díaz, Miguel; Sorolla Ayza, Mario; Campillo, Igor; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this communication we report plano-concave and bi-concave metamaterial lenses based on the close stack of subwavelegnth hole arrays. Contrary to what is expected from cut-off holes, an engineered array of holes supports Extraordinary Transmission. Moreover, the medium formed when those structures are subwavelength stacked (thus, under metamaterial condition) behaves as a medium with effective negative index of refraction, which allows designing new lenses with properties that were only guessed at not long ago such as perfect imaging, subdiffraction and free-space matching to name a few.
Open Access
Millimeter-wave phase resonances in compound reflection gratings with subwavelength grooves
(Optical Society of America, 2010) Beruete Díaz, Miguel; Navarro Cía, Miguel; Skigin, Diana C.; Sorolla Ayza, Mario; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Experimental evidence of phase resonances in a dual-period reflection structure comprising three subwavelength grooves in each period is provided in the millimeter-wave regime. We have analyzed and measured the response of these structures and show that phase resonances are characterized by a minimum in the reflected response, as predicted by numerical calculations. It is also shown that under oblique incidence these structures exhibit additional phase resonances not present for normal illumination because of the potentially permitted odd field distribution. A satisfactory agreement between the experimental and numerical reflectance curves is obtained. These results confirm the recent theoretical predictions of phase resonances in reflection gratings in the millimeter-wave regime, and encourage research in this subject due to the multiple potential applications, such as frequency selective surfaces, backscattering reduction and complex-surface-wave-based sensing. In addition, it is underlined here that the response becomes much more complex than the mere infinite analysis when one considers finite periodic structures as in the real experiment.
Open Access
Paraxiality considerations of higher order gaussian modes
(1996) Río Bocio, Carlos del; Gonzalo García, Ramón; Sorolla Ayza, Mario; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Frequently, gaussian modes are used as free space wave equation solutions. This is not true since they are obtained assuming certain paraxial character in them. In this paper, we present an original study of the condition for paraxiality of higher order gaussian modes solutions of the wave equations in free space. A bound for the product of number (k) in free space and the beam waist of a family of modes is obtained, in terms of the mode indexes - the bound being more restrictive the larger the order of the mode.