Open Access
A gap waveguide-based compact rectangular waveguide to a packaged microstrip inline transition
(MDPI, 2020) Pérez Escudero, José Manuel; Torres García, Alicia E.; Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Institute of Smart Cities - ISC
In this paper two different simple to design and easy to manufacturing transitions from a microstrip to rectangular waveguide based on ridge and groove gap waveguides are studied. The first one is based on a combination of a groove and ridge gap waveguide. In this case, the microstrip substrate occupies the whole bottom metallic housing block, namely, the transition and the gap between the bed of nails and the lid; therefore, it does not require any substrate shaping. Nevertheless, the transition needs to replace groove waveguide by ridge gap waveguide sections to avoid higher-order mode excitation. In the second approach, based on only a groove gap waveguide, the substrate is shaped to be only in the microstrip section, that is, outside the bed of nails area. This leads to a simplification of the design procedure. Prototypes of both transitions have been characterized, showing good agreement with the simulations taking into account the manufacturing tolerances. Performance comparable to the state-of-the-art in this frequency band has been achieved.
Open Access
Enhancing the infrared and visible emission properties of calcium silicate hydrate for radiative cooling using metamaterials
(IEEE, 2022) Lezaun Capdevila, Carlos; Dolado, Jorge S.; Torres García, Alicia E.; Pérez Escudero, José Manuel; Liberal Olleta, Íñigo; Beruete Díaz, Miguel; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
Two periodic structures composed of metal cylinders with different orientations are used to improve the solar reflection of calcium silicate hydrate (CSH) while maintaining its atmospheric emission. Interesting effects have been found when the distance between bars is small, suggesting that lattice effects, arising from the interaction between the rods could be leveraged in the design of these metamaterials. The size of the metal bars is selected based on state of the art micro-manufacturing techniques. This study limits its scope to a CSH gel model; i.e. the most important component of cement-based materials. Further research will be undertaken to consider a best description of the dielectric function of concrete.
Open Access
Development of sub-millimetre wave band subsystems and packaging techniques
(2019) Pérez Escudero, José Manuel; Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
En esta tesis se investigan técnicas de diseño y fabricación de dispositivos, ya sean transmisores o receptores, a frecuencias de THz y submilimétricas y técnicas de empaquetado con el objetivo de que el dispositivo final sea más compacto. Esto es interesante sobre todo pensando en uso comercial o en la integración en satélites, ya que en ambos casos la portabilidad y facilidad de uso son muy importantes. El contenido de la tesis puede dividirse en dos partes bien diferenciadas. La primera de ellas parte de la base de que no hay conectores a tan alta frecuencia y es necesario el uso de equipamiento basado en guía de onda para medir y caracterizar los dispositivos fabricados en estas bandas de frecuencia. Por lo tanto, la primera parte está orientada hacia el diseño de transiciones de tecnología planar con la tecnología en guía de onda partiendo de un análisis teórico y con el objetivo de un ensamblado sencillo. Este método ha sido aplicado a guía de onda rectangular estándar y también a tecnologías novedosas tales como Gap waveguide. Concretamente, en este trabajo se presentan cuatro transiciones en línea cuyo diseño provee ventajas desde el punto de vista computacional, por el ahorro de recursos y tiempo, además de la sencillez desde el punto de vista de fabricación y ensamblado. La segunda parte trata el diseño, análisis y fabricación de dispositivos integrados compactos basados en diodos Schottky. Específicamente, dos mezcladores de frecuencia con ocilador local basado en MMIC y un transmisor optoelectrónico. Uno de los prototipos es un mezclador cuarto armónico y el otro es un mezclador subarmónico, que usa el mismo LO e integra un multiplicador de frecuencia en el mismo substrato. Por medio de esta integración se consigue dispositivos de ensamblado más sencillo y más compactos, cuyo comportamiento es cercano al estado del arte. Además, el transmisor optoelectrónico integra el mismo substrato un fotodiodo UTC y un triplicador de frecuencia basado en diodos Schottky. De esta manera, el rango de operación del fotodiodo UTC puede ser extendido a frecuencias más altas, manteniendo sus ventajas, tales como la posibilidad de integración con fibra óptica para enlaces de alta capacidad. Por último, se ha diseñado un mezclador sexto armónico basado en la tecnología membrana de arseniuro de galio. Esta tecnología permite la integración de los diodos Schottky en la membrana junto con la circuiterí a microstrip, de tal forma que los diodos no tienen que ser soldados. En este diseño, además, un triplicador de frecuencia se integra también en la misma membrana que el mezclador armónico. Por lo tanto, el comportamiento final del mezclador sexto armónico es similar al de un mezclador subarmónico. De esta forma es más fácil encontrar fuentes con bastante potencia dado que el oscilador trabaja a una frecuencia más baja. Asimismo, gracias a la integración, los problemas causados por desalineamiento durante el ensamblado de los componentes individuales se evitan.
Open Access
Silicon integrated subharmonic mixer on a photonic-crystal platform
(IEEE, 2021) Torres García, Alicia E.; Pérez Escudero, José Manuel; Teniente Vallinas, Jorge; Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
This paper presents a planar silicon integrated subharmonic mixer on top of a photonic-crystal platform. The local oscillator (LO) power is injected through a 2D photoniccrystal (PC) slab to a resonant cavity that effectively couples the signal to a planar bow-tie antenna. The same antenna, which is printed on the top of the PC cavity, contains an antiparallel Schottky diode pair which performs the down-conversion. The proposed design is a simple, easy to integrate, low cost, low profile device. Moreover, the described fabrication process is compatible with active components integration. The performance of the design has been experimentally demonstrated showing good agreement with the simulation and is comparable with the stateof-the-art of planar mixers. The work presented here is based on concepts and technologies from electronics and photonics domains and may be a good starting point for the creation of new devices, allowing the integration and upgrading of existing techniques from both worlds.
Open Access
Surface roughness effects on ENZ media IR spectra
(IEEE, 2023-09-04) Navajas Hernández, David; Pérez Escudero, José Manuel; Liberal Olleta, Íñigo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
The development of high-performance nanophotonic technologies faces challenges like material losses and surface roughness. While surface roughness has been studied in the plasmonic regime, its effect on epsilon-near-zero (ENZ) media has been less explored. Two theoretical scenarios arise regarding roughness in ENZ media: one predicts the excitation of a strong longitudinal electric field, while the other suggests minimal changes in reflection due to the large effective wavelength. This study investigates silicon carbide (SiC) as an ENZ substrate, using deep reactive ion etching (DRIE) to create significant surface roughness. The findings show that surface roughness affects the reflection spectra, induces polaritonic effects, and highlights the robustness of SiC against surface roughness. Numerical simulations and experimental measurements confirm these results, revealing that ENZ substrates maintain their reflective properties even with surface roughness on the scale of hundreds of nanometers.
Open Access
Design of a slotted Substrate Integrated waveguide antenna using a metasurface
(IEEE, 2021) Chocarro Álvarez, Javier; Pérez Escudero, José Manuel; Ederra Urzainqui, Íñigo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In this paper, the use of a metasurface to improve the radiation properties of a Substrate Integrated Waveguide based slotted antenna is proposed. The design process of a metasurface covered 8 element slot antenna array following a Chebyshev distribution is presented and its performance is compared with that of a conventional one. The results demonstrate the improvement in the radiation performance that can be achieved, without affecting the bandwidth.
Open Access
Response of complementary split ring resonators in composite stratified substrate integrated waveguide
(American Institute of Physics, 2017) Pérez Escudero, José Manuel; Jarauta Ayensa, Eduardo; Falcone Lanas, Francisco; Beruete Díaz, Miguel; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica
In this work, the behavior of a Complementary Split Ring Resonator (CSRR) operating within the quasi-static resonance regime and embedded in a composite stratified Substrate Integrated Waveguide (SIW) with two different dielectric layers is analyzed. In these conditions, the propagating modes within the SIW combined with the imposed non-symmetrical structure lead to the excitation of the CSRR elements inside the SIW at difference with conventional excitation. Several cases of CSRR loaded SIW are proposed, and their electromagnetic field components as well as their frequency response are analyzed, providing insight into the CSRR resonance excitation. A test prototype has been designed, fabricated, and measured, showing a good agreement with simulation results and providing a new alternative for the implementation of compact frequency selective devices compatible with planar technology and without undesired radiation loss.
Open Access
A Chebyshev transformer-based microstri-to-groove-gap-waveguide inline transition for MMIC packaging
(IEEE, 2019) Pérez Escudero, José Manuel; Torres García, Alicia E.; Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
The gap waveguide technology has become an alternative to millimeter- and submillimeter-wave electronic circuit packaging thanks to the loss reduction associated with its use. In this paper, a simplified design of an inline transition between a microstrip and a groove gap waveguide (GGW) operating at the W-band is presented. The transition consists of a tapered microstrip line and a Chebyshev adapter that couple the quasi-TEM mode of the microstrip line to the so-called vertical mode of the GGW. The simplicity of this design makes this transition appropriate for monolithic microwave integrated circuit (MMIC) packaging at millimeter frequencies and above. The simulation results have been experimentally validated in the W-band. A good performance has been achieved, resulting in a return loss better than 10 dB and a mean insertion loss lower than 2 dB.
Open Access
Spectrally stable thermal emitters enabled by material-based high-impedance surfaces
(Royal Society of Chemistry, 2023) Navajas Hernández, David; Pérez Escudero, José Manuel; Liberal Olleta, Íñigo; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
Radiative thermal engineering with subwavelength metallic bodies is a key element for heat and energy management applications, communication and sensing. Here, we numerically and experimentally demonstrate metallic thermal emitters with narrowband but extremely stable emission spectra, whose resonant frequency does not shift with changes on the nanofilm thickness, the angle of observation and/or polarization. Our devices are based on epsilon-near-zero (ENZ) substrates acting as material-based high-impedance substrates. They do not require from complex nanofabrication processes, thus being compatible with large-area and low-cost applications.
Open Access
Comparison of modified Soret lenses for dual band integrated detectors
(IEEE, 2020) Torres García, Alicia E.; Pérez Escudero, José Manuel; Gonzalo García, Ramón; Ederra Urzainqui, Íñigo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
This paper presents the comparison of different modified Soret lenses suitable for a millimeter and submillimeterwave dualband integrated pixel detectors. The approach is based on the modification of a printed planar Soret lens, designed to operate in the sub-mm range, to obtain an antenna at the millimeter region. Three modifications of a transmission-mode Soret Lens at 850 GHz based on spiral, logarithmic and meander antennas geometries have been analyzed with a combination of Kirchhoffs Diffraction and full-wave simulation methods. The performance of the designs has been experimentally demonstrated in the submillimeterwave band, showing good agreement with simulation results.