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
Magnetic human body communication based on double-inductor coupling
(IEEE, 2017) Hernández-Gómez, Yicely K.; Álvarez Botero, Germán Andrés; Bacca Rodríguez, Jan; Sousa, Fernando Rangel de; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
This paper proposes a new technique for Human Body Communication (HBC) that uses the magnetic coupling in transmitter and receiver. A discussion about the presence of parasitic paths, when magnetic coupling is used in the transmitter, and electrical coupling is used in the receiver is presented; showing that the technique presented here, reduces the influence of the surrounding environment at the same time that simplifies the conventional reception schemes. In addition, a physical-based model is presented, obtaining a good model-experiment correlation up to 20 MHz. This results suggest the possibility to use the double-inductor coupling technique for the HBC channel characterization, contributing in the design of portable applications for communications systems.
Open Access
Characterization of RF-MOSFETs in common-source configuration at different source-to-bulk voltages from S-parameters
(IEEE, 2013) Zárate-Rincón, Fabián; Álvarez Botero, Germán Andrés; Torres-Torres, Reydezel; Murphy-Arteaga, Roberto S.; Decoutere, Stefaan; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Using a new test fixture that allows us to bias the bulk terminal through an additional compensated DC probe, a two-port S-measurement-based methodology to characterize RF-MOSFETs in common-source configuration is herein presented. In addition to obtaining S-parameters at different bulk-to-source voltages using a single two-port configured test-fixture, the proposal allows the analysis of the electrical parameters of a MOSFET that are influenced by the substrate effect when the frequency rises. Physically expected results are obtained for device's model parameters, allowing to accurately reproduce S-parameters up to 20 GHz. Furthermore, extracted parameters, such as threshold voltage, are in agreement with those obtained using well-established DC methods. This method allows one to characterize a four-terminal MOSFET from two-port small-signal measurements.
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
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
Characterization and modeling of the capacitive HBC Channel
(IEEE, 2015) Pereira, Maicon D.; Álvarez Botero, Germán Andrés; Sousa, Fernando Rangel de; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
The increasing interest in wireless body area networks has created the need for alternative communication schemes. One example of such schemes is the use of the human body as a communication medium. This technology is called human body communication (HBC), and it offers advantages over the most common radiation-based methods, which makes it an interesting alternative to implement body area networks. The aim of this paper is to identify the influence of a fixture on the HBC channel characterization, and an extended model that includes the test fixtures to explain the measured channel response is proposed. The model was tested against the channel measurement results, and a good experiment-model correlation was obtained. The results show that the test fixture has a nonnegligible influence and that an extended model, based on the physical meaning of the phenomena involved, helps to explain the channel frequency profile results and behavior.
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
Modeling and parameter extraction of test fixtures for MOSFET on-wafer measurements up to 60 GHz
(Wiley, 2013) Álvarez Botero, Germán Andrés; Torres-Torres, Reydezel; Murphy-Arteaga, Roberto S.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
We present a circuit model and parameter determination methodology for test fixtures used for on-wafer S-parameter measurements on CMOS devices. The model incorporates the frequency dependence of the series resistances and inductances due to the skin effect occurring in the metal pads. Physically based representations for this effect allow for excellent theory-experiment correlations for different dummy structures, as well as when de-embedding transistor measurements up to 60 GHz.
Open Access
Magneto-dielectric composites characterization using resonant sensor and neural network modeling
(IEEE, 2024) Álvarez Botero, Germán Andrés; Lobato-Morales, Humberto; Hui, Katherine; Tarabay, Naji; Sánchez-Vargas, Jeu; Vélez, Camilo; Méndez-Jerónimo, Gabriela; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza
This article presents a novel way to estimate magnetodielectric composites’ complex permittivity (ε) and permeability (µ). A methodology based on artificial neural network (ANN) modeling is proposed to determine ε and µ from S-parameter measurements around 2.45 GHz, obtained using a new microstrip split ring resonator (SRR)-based resonant sensor.
Open Access
Using S-parameter measurements to determine the threshold voltage, gain factor, and mobility degradation factor for microwave bulk-MOSFETs
(Elsevier, 2011) Álvarez Botero, Germán Andrés; Torres-Torres, Reydezel; Murphy-Arteaga, Roberto S.; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this paper, we present an extraction and characterization methodology which allows for the determination, from S-parameter measurements, of the threshold voltage, the gain factor, and the mobility degradation factor, neither requiring data regressions involving multiple devices nor DC measurements. This methodology takes into account the substrate effects occurring in MOSFETs built in bulk technology so that physically meaningful parameters can be obtained. Furthermore, an analysis of the substrate impedance is presented, showing that this parasitic component not only degrades the performance of a microwave MOSFET, but may also lead to determining unrealistic values for the model parameters when not considered during a high-frequency characterization process. Measurements were made on transistors of different lengths, the shortest being 80 nm, in the 10 MHz to 40 GHz frequency range.