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
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
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.
Open Access
Optimum horn antennas for high order mode beam waveguides
(1995) Río Bocio, Carlos del; Gonzalo García, Ramón; Sorolla Ayza, Mario; Thumm, Manfred; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Higher order free space modes can be considered as serious candidates for power millimeter wave transmission in advanced material processing by using medium power CW gyrotrons. These modes can be propagated in a beam waveguide with properly designed mirrors. Here, we present some optimal ways to excite these higher order free space modes from circular symmetric cylindrical waveguide modes by using optimal non linear horn launchers. An original synthesis procedure is proposed which has been successfully tested by computational simulation.
Open Access
Generation of the HE11 mode in rectangular waveguide using gaussian techniques
(IEEE, 1999) Teniente Vallinas, Jorge; Gonzalo García, Ramón; Sorolla Ayza, Mario; Río Bocio, Carlos del; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
A new and efficient design of a rectangular corrugated waveguide mode converter, from TE10 mode in a smooth rectangular monomode waveguide to HE11 mode in a corrugated rectangular waveguide, is proposed. The main idea is the application of Gaussian design techniques, described in the given references, previously applied in circular waveguides. By using these techniques compact and very efficient components are obtained. The obtained far field pattern is rather good as illuminator of square or rectangular parabolic reflectors, with very low sidelobes and crosspolarisation levels, avoiding the use of a rectangular to circular waveguide converter. Simulations by using the HP’s Finite Element code HFSS shown very promising results.
Open Access
Generación del modo HE11 a partir de una guía circular lisa monomodo
(1996) Gonzalo García, Ramón; Río Bocio, Carlos del; Teniente Vallinas, Jorge; Sorolla Ayza, Mario; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper, we present an original taper design to obtain the HE11 corrugated circular waveguide mode exciting with a pure TE11 monomode smooth circular waveguide mode. The proposed corrugated taper has a longitudinal section composed of two hyperbolic profiles in series, one concave and the other convex united at a point, such that the derivative is continuous. Superimposed there is an additional tapering of the corrugation depth that goes from l/2 at taper input to l/4 within the first hyperbola. This original synthesis procedure has been successfully tested by computational simulation. The calculation method has been validated by experimental results of other authors.
Open Access
High order mode beam waveguide for technological medium power millimeter wave applications
(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 use of medium power millimeter wave CW gyrotrons (10- 30 kW and 30-100 GHz) has several potential applications in advanced materials processing. Since a stochastic field distribution in the applicator is desirable no pencil beam is necessary. Then the possibility to couple the circular symmetric gyrotron output to a higher order free space mode can be considered. Beam waveguides based on iterative reflection of such high order beams on properly designed mirrors opens the possibility to increase the efficiency and to reduce costs of present compact transmission lines in gyrotron technological systems.
Open Access
Measurements of a new gaussian profile corrugated horn antenna for millimeter wave applications
(IEEE, 1998) Gonzalo García, Ramón; Martí Canales, J.; Teniente Vallinas, Jorge; Río Bocio, Carlos del; Sorolla Ayza, Mario; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
The measurements results of a new design of corrugated horn antennas [1, 2, 3] following the gaussian expansion are presented in this paper. The performance of two corrugated horn antennas of this kind was verified in the ESTEC Compact Antenna Test Range (CATR) [4]. Very high agreement between measured and predicted results is found.
Open Access
Diseño óptimo de antenas de bocina multimodo para excitar un haz gaussiano fundamental de alta pureza
(1996) Gonzalo García, Ramón; Río Bocio, Carlos del; Teniente Vallinas, Jorge; Sorolla Ayza, Mario; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper, we present an original and optimal multimode horn antenna design to excite the fundamental Gaussian beam from an overmoded waveguide. In particular, we focus the study in overmoded circular corrugated waveguide. The main idea to design this multimode horn antenna, is to increase the waveguide radius as the desired gaussian mode expands. This principle has also been applied to smooth circular waveguides to excite higher order Gaussian beams from TE0n modes. The horn antenna design considered here, improves the gaussian conversion efficiency, the crosspolarisation and the sidelobes level of some good mixture ( aprox. 85% of TE11 and 15% of TM11 ).