Open Access
Integrating multiple stubs in stepped-impedance filter aiming for high selectivity
(IET, 2022) Sami, Abdul; Gómez Laso, Miguel Ángel; Lopetegui Beregaña, José María; Arnedo Gil, Israel; Calero Fernández, Ibai; Teberio Berdún, Fernando; Martín Iglesias, Petronilo; Benito Pertusa, David; Arregui Padilla, Iván; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
A design technique to include multiple and fully-controlled transmission zeros (TZs) in the frequency response of rectangular waveguide commensurate-line stepped-impedance filters is presented in this letter. These bandpass filters (BPFs) are known for having reduced sensitivities against manufacturing inaccuracies and are composed of multiple waveguide sections. In order to improve their selectivity, 3λg/4 and λg/4-stubs are included to create multiple TZs around the passband. The proposed technique allows us to add multiple stubs in a single section and, therefore, only minor adjustments in the affected part of the filter are required, which simplifies the overall design process. The technique has been verified with a design example with four TZs (two on each side) near the passband.
Open Access
High-power filter design in waveguide technology: future generation of waveguide satellite filters in payloads handling increasing bit rates and numbers of channels
(IEEE, 2020) Arregui Padilla, Iván; Teberio Berdún, Fernando; Arnedo Gil, Israel; Percaz Ciriza, Jon Mikel; Martín Iglesias, Petronilo; Lopetegui Beregaña, José María; Gómez Laso, Miguel Ángel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
To design a filter for a particular application, many issues must first be considered. Which technology will be the most convenient? What design technique will provide better results for a particular set of frequency specifications? Once the device has been designed, will it fulfill all of the (not only electrical) requirements? It is not always easy to answer such questions in advance. In this article, we try to shed some light on these questions when our aim is the design of filters for high-power operation.
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
W-band filtering antenna based on a slot array and stacked coupled resonators using gap waveguide technology
(IEEE, 2024) Santiago Arriazu, David; Fang, Mu; Zaman, Ashraf Uz; Gómez Laso, Miguel Ángel; Lopetegui Beregaña, José María; Arregui Padilla, Iván; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
This letter proposes a new design approach for filtering antennas. The novel matching reflection coefficient based method allows the integration of filters and antennas without compromising the frequency behavior of either of these components. Moreover, this integration is done avoiding the need of lengthy optimization processes and provides a high degree of flexibility in the types of antennas that can be used. In order to validate it, two examples are provided. In both cases, a 4 th -order Chebyshev bandpass filter at 101.5 GHz implemented in stacked groove gap waveguide (GGW) configuration is used, firstly along with a single aperture antenna and, subsequently, with a slotted ridge gap waveguide (RGW) array. This second example has been manufactured to demonstrate the usefulness of the new design methodology. Excellent measured performance has been obtained for a filtering antenna at W-band for the first time.
Open Access
Synthesis of rectangular waveguide filters with smooth profile oriented to direct metal additive manufacturing
(IEEE, 2023) Percaz Ciriza, Jon Mikel; Hussain, Jabir; Arregui Padilla, Iván; Teberio Berdún, Fernando; Benito Pertusa, David; Martín Iglesias, Petronilo; Arnedo Gil, Israel; Gómez Laso, Miguel Ángel; Lopetegui Beregaña, José María; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
In this paper, a novel design method for rectangular waveguide filters intended for fabrication using direct metal additive manufacturing is proposed. The synthesized filters will feature a smooth profile that allows us to fabricate them orienting the filter propagation axis in the vertical building direction, achieving an optimum configuration for direct metal additive manufacturing fabrication. The novel design method is valid for any all-pole transfer function, which is initially implemented with a commensurate-line distributed unit element prototype. The impulse response of that initial prototype is then properly interpolated to obtain the target response for a smooth-profiled filter with similar length and profile excursion. Finally, the target impulse response just generated is implemented in rectangular waveguide technology employing a novel inverse scattering synthesis technique that relies on the coupled-mode theory to model the electromagnetic behavior of the waveguide filter. The novel inverse scattering synthesis technique is general and also valid for the case of filters with very high rejection levels, which is of great relevance in rectangular waveguide technology. A Ku-band low-pass filter with stringent satellite specifications is designed using the proposed method, fabricated by means of a direct metal additive manufacturing technique, and measured with a vector network analyzer. A very good agreement is achieved between the simulated and measured results, fulfilling the required specifications and demonstrating the feasibility and performance of the novel design method.
Open Access
Improvement of corona breakdown threshold (peak power handling) in smooth-profiled microstrip filters
(2022) Ahmad, Jamil; Hussain, Jabir; Arregui Padilla, Iván; Martín Iglesias, Petronilo; Arnedo Gil, Israel; Gómez Laso, Miguel Ángel; Lopetegui Beregaña, José María; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
In this paper, the PPHCs of two filter design techniques, stepped-impedance (SI) and smooth-profile (SP), are presented for four design prototypes. Smooth-profiled filters feature smooth variations in the characteristic impedance profile, avoiding sharp edges, which accumulate electric fields. The absence of sharp edges in SP reduces the voltage magnification factor, which in turn improves the PPHC of the filter. The phenomenon of electric fields accumulation at the sharp corners of the SI filters is presented and compared with smooth transitions in SP filters. Furthermore, 1D graphs of electric field intensity are presented along the strip contour of the microstrip lines. Finally, SPARK3D results clearly demonstrate that SP filters can handle higher peak powers than their SI counterparts between critical pressure and ambient pressure, for all the studied designs.
Open Access
Metal 3D printing for RF/microwave high-frequency parts
(Springer, 2022) Martín Iglesias, Petronilo; Gómez Laso, Miguel Ángel; Lopetegui Beregaña, José María; Teberio Berdún, Fernando; Arregui Padilla, Iván; Marechal, M.; Calves, P.; Hazard, M.; Pambaguian, L.; Brandao, A.; Rodríguez Castillo, S.; Martin, T.; Percaz Ciriza, Jon Mikel; Iza, V.; Martín-Iglesias, Santiago; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
Space Systems have been historically characterised by high performance, high reliability and high cost. Every new generation of space systems tends to improve performance, keep as much as possible reliability, speeding the lead time and lower the cost. Aggressive approach is nowadays followed by some of the players of the new space ecosystem where, for instance, reli- ability can be relaxed thanks for the in-orbit redundancy or robustness to failures by having a constellation with a high number of satellites. This push towards the technology and system limit requires to investigate new methods for the manufacturing of RF/Microwave parts. RF devices such as those based on waveguide structures, benefit from an additive manufacturing approach in terms of radio frequency (RF) performance and compactness. However each manufacturing approach comes with specific features and limitations which need to be well understood and, in some cases, even taking advantage of them. This paper provides a short review of some of the RF/Microwave parts already manufactured using this technology. The paper will focus mainly on metal 3D printing parts since this technology is, at the moment, well accepted by the space community.
Open Access
Diseño de filtro en guía de onda en banda W mediante guía multicapa con simetría glide
(URSI, 2023) García-Martínez, Sergio; Santiago Arriazu, David; Tamayo-Domínguez, Adrián; Sánchez-Olivares, Pablo; Arregui Padilla, Iván; Lopetegui Beregaña, José María; Fernández González, J. M.; Gómez Laso, Miguel Ángel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
Este artículo presenta el diseño e implementación de un filtro paso banda de cuarto orden en tecnología de guía de onda multicapa a 100 GHz. Para evitar fugas de campo en las paredes de la guía y permitir la implementación del filtro en múltiples capas sin necesidad de contacto eléctrico, se ha utilizado una estructura periódica con agujeros y simetría de deslizamiento, con agujeros circulares, como una estructura de banda prohibida electromagnética (EBG). Se presenta un filtro robusto y compacto, capaz de mantener una buena respuesta en la banda para un amplio rango de entrehierro entre capas. Este enfoque permite la implementación de la estructura compleja del filtro en bandas milimétricas, ofreciendo alta precisión y facilidad de fabricación.
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
Robust and flexible design for effective low-pass filters exploiting a passband replica
(IEEE, 2024) Santiago Arriazu, David; Gómez Laso, Miguel Ángel; Lopetegui Beregaña, José María; Arregui Padilla, Iván; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
In this paper, a design approach for effective low-pass filters (LPF) that use the Rth-passband replica of the stepped-impedance prototype response is presented. Traditional LPF design methods often rely on well-established techniques, but they may not always deliver the desired performance or flexibility. By incorporating the Rth-passband replica of the stepped-impedance prototype, we introduce a new perspective that opens up new possibilities in filter design. This approach has the potential to overcome some of the limitations associated with existing methods, offering improved filter performance, robustness, and novel design possibilities and flexibility. Additionally, we will showcase its practical application by designing, fabricating, and measuring a 5th-order gap waveguide LPF that employs the first replica as per the provided guidelines.