Open Access
Freehand system for antenna diagnosis based on amplitude-only data
(IEEE, 2021) Álvarez Narciandi, Guillermo; Laviada, Jaime; Álvarez López, Yuri; Ducournau, Guillaume; Luxe, Cyril; Belem Goncalves, Cybelle; Gianesello, Frederic; Nachabe, Nour; Río Bocio, Carlos del; Las-Heras, Fernando; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This article presents a portable system for freehand antenna diagnosis and characterization based on amplitude-only data. The amplitude-only samples are acquired by moving a handheld probe, which is tracked by a motion capture system, in front of the antenna under test (AUT) aperture. The acquired measurements are processed using the phaseless sources reconstruction method to compute an equivalent current distribution on the AUT aperture. Finally, the radiation pattern of the AUT can be obtained by evaluating the corresponding radiation integrals. Unlike previous work, the use of amplitude-only data avoids the need of a phase reference, paving the way to the diagnosis and characterization of antennas under operational conditions. This fact, together with the handheld capabilities, makes the system very convenient for measurements of already deployed and onboard antennas. Moreover, these amplitude-only acquisitions also simplify the required hardware. The system has been validated through measurements in a wide frequency range from Ka-band up to 300 GHz. Despite that one cannot expect the same degree of accuracy that can be achieved under laboratory conditions (including an anechoic environment and highly accurate positioners), the system shows excellent capabilities to detect malfunctions, such as wrong amplitude/phase distributions, as well as a fair estimation of the far field.
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
Design of concentric ring antenna arrays for isoflux radiation in GEO satellites
(Institute of Electronics, Information and Communication Engineers (IEICE), 2011) Reyna, Alberto; Panduro, Marco A.; Río Bocio, Carlos del; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
The design of concentric rings arrays for isoflux radiation is reported in this paper. This design considers the reduction of the side lobe level and the isoflux radiation requirements for Geostationary Earth Orbit (GEO) satellites. The optimization problem considers the spacing between rings and the levels of amplitude excitations. The well-known method of Particle Swarm Optimization (PSO) is utilized for the optimization. The obtained results could lead the satellite hardware to be reduced significantly even more than results presented previously in the literature.
Open Access
Diseño de filtros paso bajo usando Defected Ground Structures (DGS)
(2003) Garde Irigoyen, Ieltxu Aitor; Río Bocio, Carlos del; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper a new method of trully design of filters using Defected Ground Structures is proposed. It makes use of the model proposed in previous developments by the same authors and simplifies it to a first-order model formed only by an inductor. This is done in order to make the process easier and more straight-forward. The tabulation of the inductors which are equivalent to DGS is made varying the perimeter. This allows us to connect to the classical theory and therefore to design any desired filter. The results obtained are very good and can be applied to other cases.
Open Access
Respuesta EBG en microondas: ¿efecto Bragg o simplemente resonadores?
(2004) Ibáñez Loinaz, Asier; Río Bocio, Carlos del; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
A rigorous consideration of the EBG structures filtering effect at the microwave frequency range will be performed in this paper. We will show that in that frequency range, the periodic structure filtering (or Bragg effect) and the self-resonance of the different cells involved are tuned approximately at the same frequencies, mixing their influences in the final filter response. Both effects are defined by different geometrical laws and probably this is the main reason not to have a standard design method for a given filter requirements using these technologies.
Open Access
New coplanar waveguide based on the gap waveguide technology
(IEEE, 2021) Biurrun Quel, Carlos; Teniente Vallinas, Jorge; Río Bocio, Carlos del; Institute of Smart Cities - ISC
A new planar waveguide, coined Inverted coplanar gap waveguide is presented. The concept of gap waveguides and parallel plate suppression between perfect magnetic and a perfect electric conductors is applied to coplanar waveguides in order to create a low-dispersion, low-loss transmission line. The combination of an artificial magnetic conductor and channelized top cover allow the propagation of an even coplanar mode with a strong component propagating over the air while solving encapsulation matters without the use of metallic vias. The main theory behind this new concept is presented and supported by FEM simulations on a commercial software package.
Open Access
ASTRA 3B horn antenna design
(2010) Teniente Vallinas, Jorge; Río Bocio, Carlos del; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
The ASTRA 3B satellite includes 60 Ku-band state-of-the- art transponders and 4 Ka-band transponders. The spacecraft have been designed for the distribution of both direct-to-home (DTH) broadcast services and two way broadband services across Europe. After Astra 2B and Astra 1M, Astra 3B is the third Astra satellite to be built by ASTRIUM. Two different horn antennas, for Ku- and Ka-bands, were designed with very stringent requirements as it is usually required for space applications. For the horns the cross-polar levels should be below -45 dB, and the return loss below -30dB for all frequency bands. Normally the horn aperture is fixed by the required illumination of the reflector edges, so it is difficult to reduce the aperture size of a horn antenna. Nevertheless, thanks to the design technique used, the relation between the output aperture and the total horn length for the Ka-band was approximately 0.56 and for the Kuband was something like 0.76. This means that the lengths of the horn antennas are 1.8 and 1.32 times the respective apertures. Furthermore, the taper and the phase center movement inside the respective bandwidths could be controlled and limited to certain limits during the optimization procedure, obtaining a very efficient configuration when they were combined with the reflectors. The horn antennas were based on the combination of horizontal and vertical corrugations and they were designed by the Antenna group of the Public University of Navarra.
Open Access
Ultra-wide band corrugated gaussian profiled horn antenna design
(IEEE, 2001) Teniente Vallinas, Jorge; Gonzalo García, Ramón; Río Bocio, Carlos del; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
A corrugated horn antenna design with more than 40% bandwidth is proposed in this paper. The measured radiated field patterns have a good agreement with the simulated ones. This antenna can be used in applications that require extremely wide bandwidth with low sidelobes and low crosspolar levels, with not very strong return loss requirements.
Open Access
Comparación entre antenas cónicas corrugadas y antenas gaussianas corrugadas
(2002) Teniente Vallinas, Jorge; Gonzalo García, Ramón; Río Bocio, Carlos del; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper, a study of two equal size corrugated horn antennas; a conical and a gaussian profiled horn antenna (GPHA) has been developed. It will be demonstrated that GPHA´s provide lower sidelobes and wider bandwidths, while conical corrugated horn antennas offer higher directivities for the same aperture. Both type of antennas provide low crosspolar levels.
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.