Open Access
Assessment of performance of one-turn inductors in series configuration through a transmission-line modeling approach
(IEEE , 2024) Álvarez Botero, Germán Andrés; Moctezuma-Pascual, Eduardo; Gómez Laso, Miguel Ángel; Torres-Torres, Reydezel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza
In this paper, transmission-line theory is applied to implement a physical model for compact one-turn inductors, which simultaneously incorporates the frequency-dependent effects introduced by the conductor skin effect and the loss originated by the coupling with the ground plane. For this purpose, S-parameter measurements are processed to extract the associated parameters, which exhibit scalability with the turn radius. This allows the model to be used for interpolation and extrapolation analyses. In this regard, the device performance is assessed for one-turn inductors in series connection, for different load impedances, and when the turn is narrowed. To validate the proposal, agreement between the model and the experimental transmission line RLGC parameters, the return loss, and the Q-factor is obtained up to 20 GHz.
Open Access
Diseño de filtros en tecnología de línea coaxial sin dieléctricos mediante impresión 3D
(Universidad de Castilla La Mancha, 2024) Pons Abenza, Alejandro; Arregui Padilla, Iván; Lopetegui Beregaña, José María; Gómez Laso, Miguel Ángel; Álvarez Botero, Germán Andrés; Martín Iglesias, Petronilo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
This article presents the design and manufacturing of a fully metallic X-band bandpass filter in coaxial-line technology. The device is 3D-printed as a self-supported structure without any dielectric inside. A short-circuit λ/4 parallel stub bandpass filter provides the required mechanical support for the self-supported 3D-printing process. To enhance filter out-of-band performance, a second stage consisting of a stepped-impedance low-pass filter is integrated, also using coaxial-line technology. Both filters are designed separately and then combined to achieve desired frequency specifications. A prototype with a passband at X-band (between 8 and 12 GHz) is manufactured using Selective Laser Melting, showing excellent agreement between simulations and measurements. This approach promises highly integrated, multifunctional monoblock coaxial filters with additional benefits such as increased RF shielding and protection against electrostatic discharge.
Open Access
Integración de múltiples stubs en filtros de saltos de impedancias de alta selectividad
(URSI, 2023) Gómez Laso, Miguel Ángel; Sami, Abdul; Lopetegui Beregaña, José María; Martín Iglesias, Petronilo; Álvarez Botero, Germán Andrés; Pons Abenza, Alejandro; Arregui Padilla, Iván; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
Rectangular waveguide commensurate-line stepped-impedance bandpass filters have been shown to have an increased fabrication robustness using conventional CNC milling. In this paper, their frequency response is improved by adding multiple transmission zeros at fully-controlled positions around the passband. The technique starts with the design of the filter without transmission zeros and only requires that one of the filter sections is slightly redesigned, while the rest keep unaltered, when lambda_g/¿¿ and 3*lambda_g/¿¿ stubs are included in the section to increase the overall filter selectivity around the passband. The design example is a 7th-order Chebyshev bandpass filter in Ku-band.
Open Access
Caracterización de composites magneto-dieléctricos usando sensores resonantes de microondas y redes neuronales
(Universidad de Castilla La Mancha, 2024) Álvarez Botero, Germán Andrés; Lobato-Morales, Humberto; Hui, Katherine; Tarabay, Naji; Sánchez-Vargas, Jeu; Méndez-Jerónimo, Gabriela; Pons Abenza, Alejandro; Arregui Padilla, Iván; Lopetegui Beregaña, José María; Gómez Laso, Miguel Ángel; Vélez, Camilo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Gobierno de Navarra / Nafarroako Gobernua
In this paper, we introduce an innovative approach for determining the complex permittivity (ε) and permeability (𝜇)) of magnetodielectric composites. Our methodology uses artificial neural network (ANN) modeling to determine these key parameters from S-parameter data collected at 2.45 GHz. These measurements are performed by a novel microstrip split ring resonator (SRR)-based resonant sensor, offering enhanced precision and reliability in the estimation process.
Open Access
A 3-D-printing-oriented coaxial-line filter with wide out-of-band rejection
(IEEE, 2025-06-18) Baranowski, Michal; Pons Abenza, Alejandro; Arregui Padilla, Iván; Lopetegui Beregaña, José María; Álvarez Botero, Germán Andrés; Lamecki, Adam; Gómez Laso, Miguel Ángel; Martín Iglesias, Petronilo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
In this letter, a novel design for a 3-D-printed, self-supported coaxial-line X-band filter is presented. The filter is intended for Earth observation (EO) data downlink systems, where it must effectively reject signals in a wide frequency range. The filter design incorporates a 15th-order low-pass filter structure with a smooth profile, integrated with a short bandpass section with four $\lambda /4$ short-circuited stubs. The optimization of the low-pass section is attained by means of shape deformation, including the inner and outer coaxial conductors, and leads to a wide rejection band up to around 40 GHz, to suppress the third harmonic and other undesired out-of-band frequencies. A prototype was fabricated in one piece in an aluminum alloy using selective laser melting (SLM) and measured, exhibiting excellent agreement with simulations. In terms of out-of-band performance, the proposed coaxial-line filter is superior to other related state-of-the-art solutions.