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This work outlines the synthesis procedure for the development of ladder acoustic wave (AW) filters with uniform electro-acoustic coupling. This approach prevents the need to include external components in a final filter configuration and therefore provides a simpler and valuable network from the application point of view. The paper presents the initial synthesis process and complements it with an iterative and formulated process to obtain a ladder network with prescribed electroacoustic coupling. The process has been fully proved with a fabricated order 2 filter., Peer Reviewed, Postprint (published version)

The main area of study of this Bachelor's Thesis are the radio frequency filters. More precisely, the main objective is to design the filters that will be part of a duplexer for an environment where space is one of the most important limitations. The project starts with an overview of the types of filters that currently exist, to see what are the different possibilities to carry out the design of new filters for the environments with the previously mentioned limitations. After that, a more in-depth study of the BAW technology is carried out, which is based on the use of piezoelectric materials, which can generate acoustic waves if an electrical input stimulus is applied to them, and vice versa. In addition, this part of the theoretical study also includes a brief introduction to the concept of acoustic signals in telecommunication devices, together with the differences between these devices and the traditional ones, where only electric signals are used. Also, several measures are carried out on a duplexer created to work on a GSM base station. From these ones, the different basic requirements for a duplexer will be extracted. With these specifications obtained, the process of designing different versions of electroacoustic filters is started, with simulation software to generate the most accurate response to the requirements obtained to the measurements possible. Once the theoretical design is obtained with the simulation program, the simulation of the real implementation is carried out with real dimensions and building materials thanks to a new program that allows to obtain the responses of the different resonators that conform the designed filters. With them, new small adjustments are made to generate a response that allows to comply with the maximum possible specifications of the duplexer that has been measured., Outgoing

In recent decades, there has been a shift in the radio frequency communications sector, with an increase in the use of Acoustic-Wave technology due to the advantages these filters present over conventional ones. Primarily, the smaller size of these filters allows for more implementations, improving the device's characteristics. Acoustic wave filters are composed of piezoelectric transducers, which convert electrical signals into acoustic ones using their properties. Specifically, they can convert electrical signals into mechanical vibrations. If the propagating wave has a stationary wave pattern, this transducer is known as an acoustic resonator, and there are two types: Surface Acoustic Wave and Bulk Acoustic Wave. Acoustic filters consist of acoustic resonators and have a significant impact in the aerospace world due to their small size. Moreover, they have the advantages of better response to arbitrary signals compared to other filters, the ability to work at high frequencies, and great stability in extreme conditions. Additionally, due to their size, more acoustic filters can be implemented in the satellite, and with the help of switches, the cut-off frequencies and bandwidths can be changed remotely in real-time, making an adjustable filter. However, the main problem with acoustic resonators is that they are nonlinear elements, meaning they generate nonlinearities that negatively affect the signal. A nonlinearity is an alteration of the original signal, which can be harmonics or intermodulation distortions. The former occurs at the fundamental frequency or its multiples, and the latter is a combination of harmonics. Nonlinearities can interfere with the original signal and, in some cases, make its reception and decoding impossible, making it necessary to model nonlinearities when designing a filter to prevent or minimize their impact. Programs exist that model nonlinearities, but they consume a huge amount of resources, time, and require licences for use. There, En las últimas décadas, ha habido un cambio de tendencia en el sector de las comunicaciones de radiofrecuencia, con el aumento del uso de la tecnología "Acustic-Wave" debido a las ventajas que presentan estos filtros respecto a los convencionales. Principalmente, el tamaño más reducido de estos filtros hace que se puedan implementar más, mejorando las características del dispositivo. Los filtros de onda acústica están compuestos por transductores piezoeléctricos, los cuales convierten la señal eléctrica en acústica utilizando sus propiedades. Concretamente, tienen la capacidad de convertir las señales eléctricas en vibraciones mecánicas. Si la onda que se propaga tiene un patrón de una onda estacionaria, este transductor se conoce como un resonador acústico, y existen dos tipos, los "Surface Acoustic Wave" y los "Bulk Acoustic Wave". Los filtros acústicos están formados por resonadores acústicos, y tienen un gran impacto en el mundo aeroespacial debido a su pequeño tamaño. Además, tienen las ventajas de tener una mejor respuesta a señales arbitrarias que los demás filtros, poder trabajar a frecuencias elevadas y por tener una gran estabilidad en condiciones extremas. Adicionalmente, debido a su tamaño, se pueden implementar más filtros acústicos en el satélite, y con la ayuda de interruptores, se puede cambiar desde la distancia a tiempo real las frecuencias de corte y los anchos de banda haciendo un filtro ajustable. Sin embargo, el problema principal de los resonadores acústicos es que son elementos no lineales, es decir, generan no linealidades que afectan de forma negativa a la señal. Una no linealidad es una alteración de la señal original, pudiendo ser armónicos o distorsiones de intermodulación. La primera es a la frecuencia fundamental o en múltiplos de esta y la segunda es una combinación de armónicos. Las no linealidades tienen la capacidad de interferir en la señal original, y en algunos casos, hacer que sea imposible la recepción y codificación de esta, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura

Lateral modes are responsible for the in-band spurious resonances that appear on BAW resonators, degrading the in-band filter response. In this work, a fast computational method based on the transmission line matrix (TLM) method is employed to model the lateral resonances of BAW resonators. Using the precomputed dispersion curves of Lamb waves and an equivalent characteristic impedance for the TE1 mode, a network of transmission lines is used to calculate the magnitude of field distributions on the electrodes. These characteristics are specific to the stack layer configuration. The model’s implementation is based on nodal Y matrices, from which particle displacement profiles are coupled to the electric domain via piezoelectric constitutive relations. Consequently, the input impedance of the resonator is obtained. The model exhibits strong agreement with FEM simulations of FBARs and SMRs, and with measurements of several SMRs. The proposed model can provide accurate predictions of resonator input impedance, which is around 200 times faster than conventional FEM., This research was funded by the Catalan Government under Grant 2017 SGR 813, by Spanish Government under Grant PID2020-118410RB-C21 and Grant PID2020-113832RB-C21, and by the Secretary of Universities and Research of the Generalitat de Catalunya and the European Social Fund through Grant 2020 FI_B-00967., Peer Reviewed, Postprint (published version)

Solidly Mounted Resonators (SMRs) for high frequency RF filters and sensing applications often display spurious resonances that distort their frequency response. In this work, we try to identify the origin of spurious resonances accompanying the main series resonances in AlN-based SMRs with the help of modified Butterworth Van Dyke (BVD) and Mason’s models. By manufacturing SMRs of different sizes and shapes and studying the influence of the position of the electrical probing spot, we have demonstrated both theoretically and experimentally that devices with larger areas are more likely to display these additional peaks. Our updated models accurately simulate the frequency response of the SMRs, revealing that spurious peaks are mostly related to the resistance of the electrodes. Our study clarifies the origin of the spurious resonances and offers solutions for both, the optimal design and measurement method of SMRs., This work was supported in part by the UPC University. Department of Signal and communications [Grant BS123456], CONACYT [grant 291234] Conacyt-Secretaría de Energía-Hidrocarburos 2017 octavo período, R&D National Plan of Spanish Government [PID-2020- 118410RB-C22] and Comunidad de Madrid through the call Research Grants for Young Investigators from Universidad Politécnica de Madrid, ACUEX, APOYO-JOVENES-21-TUGJDU-108-WNZK0H., Peer Reviewed, Postprint (published version)

Tesi amb menció de Doctorat Internacional, (English) The sensing industry is constantly growing due to its demand in fields that require critical and essential information (data environment) for human safeness and quality of life. In recent years, designers, researchers and engineers have paid especial attention in at least three important characteristics in order to obtain reliable devices. These characteristics are: costs reduction, miniaturization for electronic integration compatibility (IC) and sensitivity. A promising technology that has the capacity to meet these requirements is the electroacoustic one. This technology is primary based on the propagation of surface acoustic waves (SAWs) and bulk acoustic waves (BAWs) in a piezoelectric material. For the last years, these devices have been studied and tested in different sensing applications such as gas detectors (gravimetric sensors), temperature monitoring and thin film growth. They have been tested in different fields such as automotive industry, food preservation and thin film deposition, and they have proved excellent performance. Moreover, these applications are special because the collected data occurs in harsh environments. Therefore, the required technology must possess special characteristics to meet these requirements under such environmental conditions. One more time, electroacoustic devices have showed good performance on this type of environments and conditions. BAW devices are an excellent solution to overcome the requirements needed due to their high resolution, straightforward fabrication process, high sensitivity, low costs, low size and compatibility with the IC technology. Specifically, the Solidly Mounted Resonator (SMR) configuration based on AlN is one of the best option since it has been widely studied. This configuration is well-known for its applications in Radio Frequency communication systems. Furthermore, it has demonstrated excellent performance and high quality factors in various sensing applications, even at high tempera, (Español) La industria del desarrollo de sensores está creciendo constantemente debido a su alta demanda en sectores donde se requiere información crítica y esencial para el bienestar y la calidad de vida de los seres humanos (información del medio ambiente). En los últimos años, ingenieros e investigadores han dedicado mucho tiempo en la investigación de este campo, principalmente en tres principales características que son intrínsecas del diseño de sensores. Estas características son las siguientes: la reducción de costos, la miniaturización para la integración y compatibilidad en circuitos eléctricos y la sensibilidad. Una tecnología prometedora que cumple con los requisitos mencionados es la tecnología que está basada en dispositivos electro acústicos. El principio de operación de esta tecnología está descrito por la forma en que se propagan las ondas acústicas atreves de un piezoeléctrico. Existen dos formas principales las cuales son: SAWs and BAWs. Durante las últimas décadas del siglo pasado y en el reciente se han investigado este tipo de dispositivos electro-acústicos y han sido probados en diferentes aplicaciones, por ejemplo, en el censado de masa (sensores gravimétricos), detectores de temperatura, detectores de gases y en el monitoreo del crecimiento de películas delgadas entre otros. Estas aplicaciones han sido implementadas en industrias como: la automotriz, preservación de alimentos y crecimiento de películas delgadas y en todos los campos han demostrado excelente desempeño. Además, en este tipo de aplicaciones la recogida de datos es especial porque habitualmente tiene que ser en ambientes hostiles. Por tanto, esta tecnología tiene que cumplir ciertos requerimientos y condiciones para desempeñar un buen papel en estos medios. Según las últimas investigaciones esta tecnología ha demostrado buenos resultados en dichos ambientes. Para solventar los requerimientos mencionados en dispositivos de censado para ambientes hostiles. Los sensores electro acús, Postprint (published version)

Electroacoustic filters, also known as acoustic wave (AW) filters, are very helpful in space missions since they can operate reliably under the harsh conditions of space at very high frequencies. The performance of electrical components can be harmed by the intense radiation, extreme temperatures, and other environmental stressors that spacecraft and satellites are exposed to. However, these situations can be handled by electroacoustic materials. Additionally, tuneable electroacoustic filters, which have seen a growing market in recent decades, introduce several advantages over fixed-frequency filters since they are able to operate over different frequency ranges. The fact of being able to adjust the operation band of the filter offers great flexibility as regards communication applications. Furthermore, miniaturization is another key feature for the use of electroacoustic filters in space applications as it leads to volume and mass savings. The first aim of the present thesis is to further develop the software tool for the synthesis of electroacoustic filters, FILTRAW®, in order to increase the flexibility of the design process, as well as to reduce the derived fabrication costs. The current project is embedded in the framework of a European Space Agency project to design tuneable electroacoustic filters, which aim to advance in flexible payloads. As the need for more adaptable and economical space missions grows, flexible payloads are becoming more and more crucial. Furthermore, the project is conducted within the collaborative framework between UPC and Qorvo¿, as an integral aspect of their ongoing partnership. The tool will introduce the capability to synthesize filters in transversal configuration in addition to the conventional ladder configuration. This topology was created and proved through a previous ESA project and an initial prototype for space application was manufactured. Moreover, the tool will enable the adjustment of the ladder filter synthesis outc, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura

Tesi amb continguts retallats per motius de confidencialitat, (English) During the last years, electro-acoustic technology has been a key factor in the development of portable devices thanks to its high performance and very compact filtering structures. Such a technology has enabled the inclusion of several systems and standards in a single device.Specifically, with the introduction of the new 5G and the carrier aggregation techniques, today's handset devices might have more than 50 RF filters to support usage in countries across the world. As a matter of fact, the expectation is that these numbers increase over the future. The new generation of communication standards calls for very wide bandwidths of operation and higher data rates. These requirements impose the development of ultra-wideband filters that can provide outstanding performance in terms of low loss, high rejection and multifrequency operability in the smallest possible footprint. Ladder filter topology has been the preferred one for the development of filters in the past generations of standards, since it provides very high selective filters with low insertion loss levels. However, the maximum achievable bandwidth is limited to the electro-acoustic coupling coefficient, the position of the transmission zeros depends on the resonant frequencies of the resonators and its out-of-band behavior is determined by the capacitance ratio between resonators. These shortcomings could become a bottleneck for the forthcoming stringent specifications. In a recent work, a new transversal topology has been introduced that offers a high degree of flexibility in the design of acoustic filters and it has proven to solve some of the limitations of the ladder topology. Nevertheless, its differential behavior requires of a balun stage to properly work. Moreover, some circuital transformations that are carried out in the current synthesis procedures have some limitations when ultra-wideband filters are targeted. The aim of this work is to provide novel solutions that overcome the existi, (Español) Durante los últimos años, la tecnología electroacústica ha sido un factor clave en el desarrollo de dispositivos portátiles gracias al alto rendimiento que proporcionan sus etapas de filtrado en términos de respuesta en frecuencia y tamaño. Tal tecnología ha permitido la inclusión de varios sistemas y estándares en un solo dispositivo. Concretamente, con la introducción del 5G y la aparición de nuevas técnicas de agrupación del espectro (Carrier Aggregation), los dispositivos móviles actuales pueden llegar a contener más de 50 filtros de radiofrecuencia, que permiten su uso en países de todo el mundo. De hecho, la expectativa es que estos números aumenten en el futuro. Los requerimientos de la nueva generación de estándares de comunicación se caracterizan por tener anchos de banda de operación muy amplios y velocidades de datos más altas. Estos requisitos imponen el desarrollo de filtros de banda ultra ancha capaces de proporcionar un rendimiento excepcional en términos de pérdidas de inserción, atenuación y miniaturización. Además, también deben mostrar un buen desempeño en el desarrollo de etapas de filtrado más complejas, tales como multiplexores o filtros multibanda. La topología de filtro de escalera (comúnmente conocida con su término en inglés, Ladder) ha sido la preferida para el desarrollo de filtros en las pasadas generaciones de estándares, ya que proporciona respuestas en frecuencia muy selectivas con bajos niveles de pérdidas de inserción. Sin embargo, el ancho de banda máximo alcanzable está limitado por el coeficiente de acoplamiento electromecánico, la posición de los ceros de transmisión depende de las frecuencias de resonancia de los resonadores y su comportamiento fuera de banda está determinado por la relación de capacitancia entre resonadores. Estas limitaciones podrían suponer un cuello de botella ante las estrictas especificaciones que la nueva generación de estándares plantea. En un trabajo reciente, se ha introducido una nueva topo, Postprint (published version)

This work presents the study of suspended Y-cut Lithium Niobate shear bulk acoustic resonators for wide band filter applications in the frequency range of 3.5-4.5GHz. The resonators consist of a Lithium Niobate film with Aluminum top interdigitated electrodes (IDE) and floating bottom metal plate. Through vertical electric field excitation, shear bulk acoustic waves are generated in each unit cell of the device functioning as a quasi-independent resonator. Measured devices at 3.7GHz having large relative resonance-antiresonance bandwidth of 16.7% (750MHz), with 2 O impedance at resonance are presented. Suppression of higher order lateral harmonics through etching of trenches in the Lithium Niobate and geometric optimization is discussed.2022-0205, This work is supported by Innosuisse - Schweizerische Agentur für Innovationsförderung under the grant ING-33030.1., Peer Reviewed, Postprint (author's final draft)

A good understanding of the nonlinearity mechanism in SAW devices is a crucial aspect in the filter stage. Nonlinear intermodulation distortion (IMD) may lead to spurious signals falling into the receiver band and limiting its sensitivity. Identify the dominant source of nonlinearity specially at high-power is important for a good prediction of the filter nonlinear response. In this work, third-order intermodulation (IMD3) products in TC-SAW (Temperature Compensated-SAW) devices are presented. Within this work we apply the previously developed Input-Output Equivalent Sources (IOES) method to compute nonlinearities of more complex structures such as ladder-type and CRF (Coupled Resonator Filter) filter structures., This work was supported in part by the Spanish Government through grant PID2020-118410RB-C21. Research was also supported by the Secretary of Universities and Research of the Generalitat de Catalunya and the European Social Fund through grant FI_B-00136., Peer Reviewed, Postprint (author's final draft)

In this work we theoretically and experimentally assess the behavior of AlN-based Solidly Mounted Resonators (SMR) at cryogenic and high temperatures. This study can be useful for precise behavior prediction of SMR sensors working as gas detectors in the food preservation industry, or the industrial and automotive ones. We have subjected SMRs to temperatures from -160°C up to 130°C in high vacuum conditions (6×10 -7 mBar) and compared their experimental performance to a modelled one. We employed an updated mBVD model that includes low temperatures effects, and we show good accuracy between data. Our SMRs have fairly preserved their quality factors and electromechanical coupling factors at both cryogenic and high temperatures: Qa= 482, Qr = 288 and k eff = 6.30% at -160°C to a Qa = 477, Qr = 265 and k eff = 6.39% at 130°C., This work was supported by the next projects: TEC2017-84817-C2-2-R, TEC2017-88343-C4-2-R, TEC2017-84817-C2-1-R, 2017 SGR-813 and Conacyt-México., Peer Reviewed, Postprint (author's final draft)

The motivation of this work is to analyze the in-band intermodulation distortion (IMD) occurring in surface acoustic wave (SAW) devices, using a recently developed fast method based on the input–output equivalent sources (IOES). The method calculates the equivalent current sources of a given harmonic (H) or IMD, which when applied at the boundaries of any uniform nonlinear region produce the same nonlinearities as the full distributed circuit. The accuracy of the method is validated with a very simplified SAW resonator with ten digits, which is modeled by a discretized Mason-based circuit. The IOES method provides equal results to the ones obtained through harmonic balance (HB) simulations, performed by means of commercial software, being the first 1000 times faster. Once the accuracy of the method is guaranteed, it is used to analyze the measured in-band IMD3 of several lithium tantalite 42° cut leaky SAW (LSAW) resonators with different pitches and duty factors at the B66 long term evolution (LTE) frequency band. Those resonators are comprised of 100 and 20 electrode pairs for the active region and each of the reflectors, respectively, which implies the analysis of a very large distributed nonlinear problem with thousands of nonlinear local sources. The IOES method takes 35.4 s in simulating 51 frequency points, whereas this simulation is not possible using a commercial HB simulator on a general-purpose computer., This work was supported in part by the Spanish Gov. through grants PID2020-118410RB-C21 and PID2020-113832RB-C21 funded by MCIN/AEI/10.13039/50110001103 and by the Catalan Gov. under grant 2017 SGR-813., Peer Reviewed, Postprint (author's final draft)

Aquesta tesi es desenvolupa en el context de la missió Lunar GNSS Receiver Experiment de la NASA i la ASI, que té com a objectiu demostrar el posicionament, la navegació i el temps basats en GNSS a la Lluna mitjançant el desplegament d'un receptor multiconstel·lació del sistema de navegació per satèl·lit amb cobertura global. El projecte es desplega sota la supervisió del grup NavSAS del Politecnico di Torino. La finalitat del projecte és el desenvolupament d'una aplicació que permeti l'anàlisi i simulació de mesures GNSS sense processar. El software ha de ser modular, flexible i fàcil d'utilitzar., Outgoing

The ESA wants to implement tuneable acoustic filters in satellite communication, with various purposes, one of which is to reduce the size of the circuit and have a high-quality factor. The two frequency bands in which it wants to work are 200 MHz and 1 GHz. In this work, we will focus on obtaining various filter topologies in the 1 GHz band. The first step is the Introduction, where you will start by commenting on the idea of the project and who the members are. After the idea is clear, the objective will be set and how it will be carried out step by step. Having gone through the Introduction and knowing that it will be done at every moment, it will give way to Chapter l, here you will know what behaviours the acoustic resonator has, you will see the different electroacoustic resonator configurations, such as SAW, BAW, SH0, X- BAR. In this way, you will know and be able to understand how the chosen configuration, the BVD, works. Next, it will be shown which theoretical analysis have been carried out to have an acoustic filter and which steps have been followed for the implementation and evaluation of the two acoustic configurations. Having done the theoretical analysis and the procedure done, we will move on to Chapter II, where most of the practical part is carried out. To be able to carry out this function, two tools will be used, the ADS to be able to do the simulations of the different topologies used and the MATLAB, to have all the calculations and graphics in a more dynamic and fast way. At this point, the tuning of each topology and the evolution of certain elements will be shown depending on the frequency being worked on. Finally, the real elements that are on the market and those that will be used will be shown. Finally, a series of comparisons with other topologies of acoustic filters will be shown, in this way you will see which topology is most interesting for the frequencies you want to act on.

Transversal networks for electroacoustic filters had been proposed and manufactured recently. One of the main problems that arose in the first prototype were the spurious modes due to the mirror stack of the Solidly Mounted Resonators (SMR). In this work, different approaches for solving this problem are discussed, relying on Mason's circuit-based simulations of each resonator and of the filter topology. The main drawbacks and advantages of the different approaches are discussed in terms of fabrication and mirror efficiency., This work was supported in part by the Catalan Government under Grant 2017 SGR 813, in part by the Spanish Government under Grant TEC2017-84817-C2-2-R and Grant TEC2017-88343-C4-2-R, and was also supported by the Secretary of Universities and Research of the Generalitat de Catalunya and the European Social Fund through grant 2020 FI_B-00967., Peer Reviewed, Postprint (published version)

The transversal filter topology consists of resonators which require both positive and negative coupling to the input/output which typically necessitates the use of a BALUN. In this paper, transversal filters based on stacked crystal filters (SCFs) are presented. By inverting the polarity in one side of the SCF structure, both positive and negative couplings can be achieved, and the BALUN is no longer needed. In addition, a new approach to suppress spurious modes of SCFs is introduced. © 2021 IEEE., Peer Reviewed, Postprint (published version)

We study the presence of an additional peak appearing at the series resonance of SMRs due to the resistance of thin metallic electrodes, especially relevant in devices with large area. To properly account for this effect, we have modified the traditional Mason and BVD models by adding a parallel branch with different series resistors. Finally, we validated these models with fabricated resonators. This work is important for SMRs sensing applications as the presence of the spurious peak can distort the response of the sensor by limiting its resolution and limit of detection., Peer Reviewed, Postprint (published version)

Tesi amb diferents parts encriptades per motius de confidencialitat, Nowadays, mobile devices have become a key technology in our lives, making us become part of a connected world, in which millions of mobile handsets are sold every year. In order to satisfy the user demands, many mobile communication standards are working together in the same device (LTE-A, 5G-NR, IEEE Wireless LAN Standards, etc.). High data rates are demanded for different wireless services working on a very crowded frequency spectrum, where all the devices and systems need to operate at the same time without detrimental of mutual interference. Although this major objective has to be faced from different perspectives, such as new modulations and new networking protocols, the radio frequency (RF) and microwave components, forming the communication chain in a transceiver, play a significant role on the whole system performance. Passive devices, like filters, contribute to the signal degradation due to passive intermodulation (PIM). PIM can be generated by the lack of mismatch between metallic contacts, oxidation, or basically, by the inherent nonlinear material properties used on the fabrication of the devices. Although the impact of PIM is lower than the distortion introduced by active devices, for current wireless services and their demanding requirements, any type of nonlinear generation is certainly an issue. Acoustic wave (AW) devices have become a fundamental technology for portable handsets supporting current wireless communication networks. Bulk Acoustic Wave (BAW) has become the main technology nowadays for high frequency filters. This technology allows a high degree of miniaturization, easily making more than 40 filters per device, and also gives other advantages as low insertion losses and multiple frequency operation. Despite these major advantages, BAW resonators exhibit a nonlinear behavior, i.e., they may suffer of intermodulation and harmonic distortion, which might become a real bottle neck for the full expansion of the technology in the ever increa, Avui en dia, els dispositius mòbils s’han convertit en una tecnologia clau a les nostres vides, fent-nos formar part d’un món connectat, en el qual es venen milions de telèfons mòbils cada any. Per tal de satisfer les demandes dels usuaris, molts estàndards de comunicacions mòbils treballen junts en el mateix dispositiu (LTE-A, 5G-NR, IEEE Wireless LAN Standards, etc.). Es requereixen altes velocitats de transmissió de dades per als diferents serveis de comunicació sense fils, treballant en un espectre de freqüències molt concorregut, on tots els dispositius i sistemes han de funcionar al mateix temps sense interferir-se mútuament. Tot i que aquest objectiu principal s’ha d’afrontar des de diferents perspectives, com ara noves modulacions i nous protocols de xarxa, els components de radiofreqüència i de microones, que formen la cadena de comunicacions en un transceptor, tenen un paper important en el rendiment de tot el sistema. Els dispositius passius, com els filtres, contribueixen a la degradació del senyal a causa de la intermodulació passiva (PIM). La PIM es pot generar per el desajust entre contactes metàl·lics, l’oxidació o, bàsicament, per les propietats no lineals inherents dels materials que s’utilitzen en la fabricació dels dispositius. Tot i que l’impacte de la PIM és inferior a la distorsió introduïda pels dispositius actius, per als serveis sense fils actuals i els seus requisits exigents, qualsevol tipus de generació no lineal és sens dubte un problema. Els dispositius d’ona acústica (AW) s’han convertit en una tecnologia fonamental per a telèfons mòbils treballant a les xarxes de comunicació sense fils actuals. La tecnologia Bulk Acoustic Wave (BAW) s’ha convertit avui en dia en la principal tecnologia per filtres d’alta freqüència. Aquesta tecnologia permet un alt grau de miniaturització, podent fabricar més de 40 filtres per dispositiu i també ofereix altres avantatges com baixes pèrdues d’inserció i el funcionament a freqüències múltiples. Malgrat, Postprint (published version)

This work presents the complete synthesis procedure and circuit transformations needed to go from the characteristic polynomials to the transversal network formed by electroacoustic resonators. This filter topology allows the possibility to achieve any filter response in spite of limited electroacoustic coupling. This is crucial for obtaining very wideband filters with arbitrary positions of transmission zeros. Additional circuit transformations reveal the flexibility of such topology to control other important parameters of the acoustic filter such as the impedance of the resonators and their resonant frequencies, which directly affect the manufacturing process. The transversal topology for electroacoustic filters has been verified by the synthesis, design, fabrication, and measurement of a very wideband filter to meet the requirements of 5G N77 frequency band, centered at 3.75 GHz with 910 MHz of bandwidth., This work was supported in part by the Catalan Gov. through grant 2017 SGR 813, and by the Spanish Gov through grants TEC2017-84817-C2-2-R, TEC2017-88343-C4-2-R and the ESA Contract No. 4000124123/18/NL/CRS., Postprint (author's final draft)

This work provides a new procedure to synthesize acoustic wave ladder filters starting with series resonators. The novelty of this method relies in a new synthesis methodology to extract a series inductance in filter configurations starting in series resonators. As a matter of fact, this new synthesis provides solutions with a reduced value of the electrostatic capacitance, thereby giving resonators with smaller size., This work have been supported by the Spanish Government through grants TEC2017-84817-C2-2-R, TEC2017-88343-C4- 2-R, the Secretary of Universities and Research of the Generalitat de Catalunya through 2017 SGR 813., Peer Reviewed, Postprint (author's final draft)

Improving power handling and lifetime are key assets to ensure device performance and reliability. SAW resonators composed by very thin cross-section inter-digital transducer (IDT) structures make difficult to control the current density and thus acoustomigration plays and important role since degradation of the metallization is one of the main failure modes. The motivation of this work is to monitor and characterize the resonator behavior even at high powers levels that can damage the device. The method is based on a feed-forward-based technique to measure the reflection coefficient of SAW resonators under a fixed-frequency high power heating (HPH) signal., This work was supported in part by the Spanish Government through grants TEC2017-84817-C2-2-R, TEC2017-88343-C4-2-R and 2017 SGR-813. Research was also supported by the Secretary of Universities and Research of the Generalitat de Catalunya and the European Social Fund through grant FI_B-00136., Peer Reviewed, Postprint (published version)

In this paper we present an updated version of the well-known one dimensional model for Solidly Mounted Resonators (SMRs) based on Aluminum Nitride (AIN) for harsh environments at 2.4 GHz in sensing applications. Our model covers from 22°C up to 422°C and presents this performance. Qa=900,Or=350 and keff=6.17% at 22°C to a Qa=380,Qr=150 and keff=5.48% at 422°C Also we have verified our model using measurements from fabricated SMRs with an acoustic reflector of seven alternating layers of low and high acoustic impedance., This work was supported by the next projects: TEC2017-84817-C2-2-R, TEC2017-88343-C4-2-R, TEC2017-84817-C2-1-R, 2017 SGR-813 and Conacyt-México., Peer Reviewed, Postprint (published version)

Tesi amb diverses seccions retallades per raons de confidencialitat, The meteoric growth of the mobile communication market for the last three decades has been strongly related with the evolution of the electroacoustic (EA) filter technology. With way over 5 billion cell phone users worldwide in 2017 and 5G standard in the horizon, the radiofrequency spectrum is becoming increasingly crowded whereas demand for mobile data has no expected limits in the short to medium term. In this scenario, where a unique filter needs to be designed for each band of operation, requirements for advanced filtering solutions continue to grow as well as the average value of the RF solutions and the RF content per mobile device. RF and microwave devices based on EA resonators such as Bulk Acoustic Wave (BAW) and Surface Acoustic Wave (SAW) filters overcame the limitations of the existent technologies back in the 1980’s thanks to its compatibility with the manufacturing process of standard Silicon Integrated Circuits (Si-IC). Nowadays sophisticated RF Front-End (RFFE) Modules based on System-in-Package (SiP) are the key solution to integrate the increasing number of electronic parts - Power Amplifiers (PAs), Low Noise Amplifiers (LNAs) and switches - that accompanies acoustic filtering devices like filters, duplexers and multiplexers. Even though the level of complexity and accuracy present on the current EA devices is extraordinary, the design procedures for acoustic filters are still based on the optimization of built-in performance parameters from behavior-based compact models of resonators and the success on this duty relies mostly on the expertise of the designers. However due to the stringent technological constrains and the increasing complexity of the RFFE module architectures devoted to satisfy demanding specifications of the current and forthcoming communications standards, the challenging work of the designers is never getting easier. The aim of this work is focused on providing valuable insights that might help to overcome some of the existent, El creixement meteòric del mercat de comunicacions mòbils durant les últimes tres dècades ha estat fortament relacionat amb l'evolució de la tecnologia de filtres electroacústics (EA). Amb més de 5 bilions d'usuaris de telefonia mòbil al món i amb implantació del 5G a l'horitzó, l'ocupació de l'espectre de radioelèctric és cada cop més gran, mentre que la demanda de dades mòbils no para de créixer exponencialment. En aquest escenari, on s'ha de dissenyar un filtre únic per a cada banda d'operacions, continuen creixent els requisits per a solucions de filtratge avançades, així com el valor mitjà de les solucions RF i el contingut de RF per dispositiu mòbil. Els filtres de radi i microones basats en ressonadors EA com Bulk Acoustic Wave (BAW) i Surface Acoustic Wave (SAW) filtren la superació de les limitacions de les tecnologies existents a la dècada de 1980 gràcies a la seva compatibilitat amb el procés de fabricació de circuits integrats de silici estàndard (Si -I C). Actualment, els sofisticats mòduls de front-end RF (RFFE) basats en System-in-Package (SiP) són la solució clau per integrar el nombre creixent de peces electròniques (amplificadors de potència (PA)), amplificadors de baix soroll (LNAs) i interruptors - que acompanya. dispositius de filtratge acústic com filtres, dúplex i multiplexors. Tot i que el nivell de complexitat i precisió presents als dispositius EA actuals és extraordinari, els procediments de disseny dels filtres acústics continuen basant-se en l’optimització de paràmetres de rendiment integrats a partir de models compactes de ressonadors basats en el comportament i l’èxit d’aquest servei es basa. principalment en l’experiència dels dissenyadors. No obstant això, a causa de les estrictes limitacions tecnològiques i la creixent complexitat de les arquitectures del mòdul RFFE dedicades a satisfer les especificacions exigents dels estàndards de comunicació actuals i propers, el treball desafiant dels dissenyadors no és mai fàcil. L'objectiu d', Postprint (published version)

The recently proposed transversal topology for creating acoustic filters allows to achieve arbitrary filter responses, in terms of position of transmission zeros and bandwidth, among others. This new topology might indeed help to give response to the demanding filter specification of the recent and future wireless communication systems, some not yet achievable with the conventional ladder configuration used in acoustic technology. Full success of the transversal configuration to this end also requires meeting decent nonlinear responses. This work makes use of a comprehensive nonlinear equivalent circuit model to analyze and evaluate the nonlinear response, in particular the second harmonic (H2), of acoustic transversal filters. This work evaluates the effects of the filter bandwidth, electro-acoustic coupling and goes one step further to propose variation of the topology to provide filter responses with reduced nonlinear effects., Work supported by the Spanish Government through grants TEC2017- 84817-C2-2-R, TEC2017-88343-C4-2-R, the Secretary of Universities and Research of the Generalitat de Catalunya through 2017 SGR 813, Peer Reviewed, Postprint (published version)

Understanding the mechanism of nonlinearity in SAW/BAW devices is growing up in importance because these, even being weak, can cause desensitization of the receivers and limiting their performance. Proper nonlinear distributed models have been extensively used, usually running Harmonic Balance (HB) simulations being in some cases very time consuming. The motivation of this work is to apply a new method of analysis for the simulation of harmonics (H) and intermodulation products (IMD) generation in SAW devices. The method is called the Input-Output Equivalent Sources (IOES) and it allows extremely fast and robust simulations of large distributed weak nonlinear circuits., This work was supported in part by the Spanish Gov. through grants TEC2017-84817-C2-2-R, TEC2017-88343-C4-2-R and 2017 SGR-813. Research wasalso supported by the Secretary of Universities and Research of the Generalitatde Catalunya and the European Social Fund through grant FI_B-00136., Peer Reviewed, Postprint (published version)

ADS-B presents itself as the surveillance technology that will provide aircraft controlling for years to come. By virtue of its broadcast nature, private companies such as Aistech Space are able to obtain and process huge amounts of real aircraft trajectory data and develop their own products and algorithms for commercial use. The first part of this project consists of conducting research on the cutting edge ADS-B derived applications in order to select a viable candidate to be developed in the second part. The elected topic was a tool for predictive maintenance against adverse effects of dust ingestion in wind turbines. The second part consists of the research for viable sources of atmospheric composition, obtained from satellite imagery, an

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works, This work presents a new method to analyze weak distributed nonlinear effects, with focus on the generation of harmonics (H) and intermodulation products (IMD) in bulk acoustic wave resonators and filters composed of them. The method consists of finding equivalent current sources (Input-Output Equivalent Sources) at the H or IMD frequencies of interest, that are applied to the boundary nodes of any layer that can contribute to the nonlinearities according to its local nonlinear constitutive equations. The new methodology is compared with the harmonic balance analysis, by means of a commercial tool, of a discretized nonlinear Mason model, which is the most used model for nonlinear bulk acoustic wave resonators. While the computation time is drastically reduced, the results are fully identical. For the simulation of a 7th order filter, the Input-Output Equivalent Sources method is around 700 times faster than the harmonic balance simulations., This work was supported in part by the Catalan Gov. through grant 2017 SGR 813, and by the Spanish Gov through grants TEC2017-84817-C2-2-R, TEC2017-88343-C4-2-R., Peer Reviewed, Postprint (author's final draft)

This is the pre-peer reviewed version of the following article: González‐Rodríguez, M., Collado, C., González‐Arbesú, J. M., Mateu, J., Montoro, G., & Gilabert, P. L. (2021). Tone injection‐based cancellation technique for nonlinear distortion reduction of modulated signals in BAW resonators. Microwave and Optical Technology Letters, 63(3), 781-786, which has been published in final form at https://onlinelibrary.wiley.com/doi/10.1002/mop.32670. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions., A technique for the reduction of third-order intermodulation distortion (IMD3) occurring in bulk acoustic wave (BAW) filters and multiplexers is presented. The method consists of using the intrinsic second-order intermodulation distortion generated by BAW filters and multiplexers themselves by injecting an externally controlled amplitude and phase modulated signal at low frequency to compensate for the IMD3. The proposed technique has been experimentally verified by performing IMD3 measurements in a single BAW resonator subject to several modulated signals under a nonlinear scenario., Secretary of Universities and Research of the Generalitat de Catalunya and the European Social Fund, Grant/Award Number: FI_B-00136; Spanish Government, Grant/Award Numbers: 2017 SGR-813,TEC2017-84817-C2-2-R, TEC2017-88343-C4-2-R, Peer Reviewed, Postprint (author's final draft)

An equivalent circuital model is proposed for the lateral modes of a BAW resonator. It is based in the Mason model, adding a dispersive a transmission line to model the Lamb waves along the lateral dimensions of the resonator. The lateral perturbation of the longitudinal strain is added into the nonlinear constitutive relations. Validation of the model is performed with H2 measurements of Type I rectangular SMR devices., Peer Reviewed, Postprint (published version)

This paper presents the synthesis and circuit transformations of acoustic wave filters based on a transversal arrangement of the individual resonators. This configuration allows for the synthesis of any filter response without detrimental of the limited value of the electro-acoustic coupling coefficient. The synthesis can be performed in the low-pass domain to be latter transformed into the band-pass domain. This latter step results in significant differences between the low-pass and the band-pass responses in wideband stringent filters. This work, after an initial synthesis in the low-pass domain, directly applies the pass-band circuit transformation achieving a more accurate synthesized network even for wideband filters., This work has been supported by the Spanish Government through grants TEC2017-84817-C2-2-R, TEC2017-88343-C4-2-R and the Secretary of Universities and Research of the Generalitat de Catalunya through 2017 SGR 813., Peer Reviewed, Postprint (published version)

As the power requirements in BAW filters steadily increase, thermal behaviour emerges as a key asset to ensure device performance and reliability. Under these conditions, self-heating mechanisms drive to possible situations where the filters no longer meet the electrical specifications. In addition to that, the evaluation of the heat spreading might help to define the resonators and pillars distribution along with the overall performance of current BAW filters. In the past, numerical methods based on FEM have been used to study the temperature distribution under high-power (HP) signals, lacking efficiency in terms of computational time. The motivation of this work is to describe an analytical method that is able to simulate very fast, without the need of costly FEM simulation, the heat spreading in a filter according to the spatial distribution of the resonators., This work was supported in part by the Spanish Gov. through grants TEC2017-84817-C2-2-R, TEC2017-88343-C4- 2-R and 2017 SGR-813. Research was also supported by the Secretary of Universities and Research of the Generalitat de Catalunya and the European Social Fund through grant FI_B00136, Peer Reviewed, Postprint (published version)

This work shows the feasibility of using filters with transversal configuration to create N-Plexers and N-Band responses, by directly connecting several BAW filters in a transversal manner. The new multi-filtering solutions might indeed help on the existing and forthcoming challenges for LTE or 5G, such as the efficient management of the limited spectrum allocation or the non-contiguous spectrum, with the aim of increasing the network capacity and higher data rates. The filter arrangement proposed shows as well flexibility on dynamic scenarios like the ones occurring in a Carrier Aggregation (CA) access [1]., This work was supported in part by the Spanish Government through grants TEC2017-84817-C2-2-R, TEC2017-88343-C4-2-R, the Secretary of Universities and Research of the Generalitat de Catalunya through 2017 SGR 813 and ESA Contract No. 400012413/18/NL/CRS., Peer Reviewed, Postprint (published version)

An equivalent circuit model is proposed in order to model the Border Ring (BR) spurious modes on Type I Solidly Mounted Resonators (SMR) BAW resonators and the cancellation of the in-band lateral modes that the BR frame produces. The model has been validated through FEM simulations and with measurements of resonators. It predicts the electrical response of the BR effects for different resonators and BR sizes., This work was supported in part by the Spanish Government through grants TEC2017-84817-C2-2-R, TEC2017-88343-C4-2-R and 2017 SGR-813., Peer Reviewed, Postprint (published version)

This work applies a comprehensive nonlinear characterization process of two Temperature Compensated Bulk Acoustic Wave (TC-BAW) resonators. In both resonators, the SiO 2 layers have a remarkable impact on the generation of third- order intermodulation products (IMD3), confirming the impact of the SiO 2 on the generation of passive intermodulation. A unified model considering the electro-thermo-mechanical constitutive relations of the piezoelectricity is used, that allows to discern on the origin of the IMD3, either it comes from intrinsic nonlinearities of the materials, or from self-heating mechanisms., This work was supported in part through grants TEC2017-84817-C2-2-R, TEC2017-88343-C4-2-R and 2017 SGR 813. With the support of the Universities and Research Secretary of the Generalitat de Catalunya and the European Social Fund through grant 2018FI_B_00448, Peer Reviewed, Postprint (published version)

This paper evaluates important aspect of acoustic filters based on a transversal configuration in order to foreseen the potential and limitations of this new configuration. These aspects are: effects of the losses of the resonators and external components, such as capacitors and inductors, sensitivity on the deviation of the impedance and resonant frequency of the resonators and effects of having a non-ideal balun. This study has been performed in a sixth order filter with asymmetric position of the transmission zeros., Work supported by TEC2017-84817-C2-2-R, TEC2017-88343-C4-2-R, 2017 SGR 813, ESA- 400012413/18/NL/CRS., Peer Reviewed, Postprint (published version)

This paper performs a comprehensive nonlinear modeling of a Bulk Acoustic Wave (BAW) duplexer operating at the band 7 of the LTE wireless communication standard. The modeling starts by an accurate characterization of the resonators forming the filters by performing measurements of the second harmonic (H2). The modeling of individual resonators has then been used to predict second order nonlinear manifestations occurring in a real duplexer. These are H2, second order intermodulation products (IMD2), for the case where a jamming signal is set to low frequencies (IMD2-Low) and when the jamming signal is set to high frequencies (IMD2-High). Predicted results are then validated with real measurements., The authors would like to thank Qorvo Inc. for providing the on-wafer measurements that appear in this article. Work supported in part through grants TEC2017-84817-C2-2-R, TEC2017-88343-C4-2-R and 2017 SGR 813, Peer Reviewed, Postprint (published version)

This article discusses on the measured third-order intermodulation (IMD3) products and third harmonics (H3) appearing in a set of six different solidly mounted resonators (SMR) and bulk acoustic-wave (BAW) resonators with different shapes and stack configurations. The discussion is supported by a comprehensive nonlinear distributed circuit model that considers the nonlinear effects potentially occurring in any layer of the resonator stack. The aluminum-nitride (AlN) and silicon-dioxide (SiO2) layers are identified as the most significant contributors to the IMD3 and H3. The frequency profile of the third-order spurious signals also reveals that, in temperature-compensated resonators, where the SiO2 layers are usually thicker, the remixing effects from the second-order nonlinear terms are the major contributors to the IMD3 and H3. These second-order terms are those that explain the second-harmonic (H2) generation, whose measurements are also reported in this article. Unique values of the nonlinear material constants can explain all the measurements despite the resonators have different shapes, resonance frequencies, and stack configurations., Peer Reviewed, Postprint (author's final draft)

This paper presents a novel filter configuration based on acoustic wave resonators that allows to obtain filter responses unachievable with the well established ladder configuration, such as arbitrary position of transmission zeros, multiband filtering responses and wideband performances. Additional advantage of such configuration is the full flexibility to prescribe the coupling coefficient of each resonator by the designer. The present work outlines the concept behind this new configuration. Several examples will be shown to illustrate the benefits of this novel approach., Peer Reviewed, Postprint (published version)

This is the peer reviewed version of the following article: A. M. Hagerstrom, X. Lu, N. M. Dawley, H. P. Nair, J. Mateu, R. D. Horansky, C. A. E. Little, J. C. Booth, C. J. Long, D. G. Schlom, N. D. Orloff, Adv. Mater. Technol. 2018, 3, 1800090. https://doi-org.recursos.biblioteca.upc.edu/10.1002/admt.201800090, which has been published in final form at https://doi.org/10.1002/admt.201800090. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving., Voltage-tunable dielectric materials are widely used for microwave-frequency signal processing. Among tunable dielectric thin films, (SrTiO3)nSrO Ruddlesden–Popper (RP) superlattices have exceptionally low loss at high frequencies. This paper reports the first realization of resonators, a ubiquitous building block of microwave components, fabricated on RP films, and an analysis of their static and dynamic tuning behavior. The RP film has a ferroelectric-paraelectric phase transition at ˜200 K, and the tunability is strongest at this temperature. The resonators have approximately 2.5% tuning of the resonance frequency at room temperature and 20% tuning at 200 K, and a tuning time scale of less than a nanosecond, which is limited by the measurement circuit rather than material properties., Peer Reviewed, Postprint (author's final draft)

©2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., With emerging medical, chemical, and biological applications of microwave-microfluidic devices, many researchers desire a fast and accurate calibration that can be achieved in a single connection. However, traditional on-wafer or coaxial calibrations require measurements of several different artifacts to the data prior to measuring the microwave-microfluidic device. Ideally, a single artifact would be able to present different impedance states to correct the vector network analyzer data, minimizing drift and eliminating artifact-to-artifact connection errors. Here, we developed a multistate single-connection calibration that used a coplanar waveguide loaded with a microfluidic channel. We then used measurements of the uncorrected scattering parameters of the coplanar waveguide with the channel empty, filled with deionized water, and filled with 30 w% (30 grams per liter) of saline to construct an eight-term error model and switch-term correction. After correction, the residuals between measured scattering parameters and with the literaturebased finite-element simulations were below -40 dB from 100 MHz to 110 GHz. This multistate single-connection calibration is compatible with both wafer-probed and connectorized microwave-microfluidic devices for accurate impedance spectroscopy and materials characterization without the need for multiple device measurements., Peer Reviewed, Postprint (author's final draft)

Acoustic filters are, without any doubt, the key technology for the development of highly miniature high performance RF/Microwave filters. Such a technological and engineering effort has been one of the driving forces for the expansion of handset wireless devices, such as smart phones, tablets and other portable gadgets (integrating +50 filters each of those portable devices). The main features of current acoustic wave (AW) filters: low insertion loss, sharp frequency response and highly miniaturized, in comparison with other technologies, are highly desirable in RF components for space applications., Peer Reviewed, Postprint (published version)

This work presents the development of a Matlab software tool based on a non-iterative method for the nonlinear analysis of Bulk Acoustic Wave (BAW) resonators and filters. The procedure starts with the admittance matrix extraction of the distributed circuit that models a resonator. The aim of this procedure is to avoid high computation times and/or convergence problems that usually appear when performing Harmonic Balance (HB) simulations of very large circuits, as those resulting from a distributed model of a BAW resonator with a high discretization level. Moreover, the procedure allows to simulate the potential isolated contribution of each nonlinear coefficient that appear in the constitutive equations with a low penalty in terms of computation time. As an example, this analysis capability is integrated with an optimization algorithm that is able to find the first order nonlinear coefficients that better match the second harmonic (H2) broadband measurements of a device., Peer Reviewed, Postprint (published version)

This work presents a new technique to cancel third-order intermodulation distortion (IMD3) by using a low frequency injected tone to generate a second-order intermodulation product (IMD2) that fall exactly at the same frequency of the undesired IMD3. The phase and amplitude of the injected tone are controlled to cancel out the IMD3. A proper characterization and a good modeling are needed to demonstrate the concept. Narrow band characterization and modeling of second harmonic (H2) and IMD3 in a Bulk Acoustic Wave (BAW) resonator has been done to evaluate the nonlinear contribution of each material composing the resonator and to identify the dominant nonlinear terms. The concept of this technique will be demonstrated by doing measurements of an on-wafer resonator. The measurement system, including the cancellation procedure, will be described. The cancellation achieved with this technique is in good agreement with the simulations., Peer Reviewed, Postprint (published version)

This work presents the nonlinear modeling of a real acoustic wave filter set at the cellular commercial receiver band B40. The paper outlines the synthesis procedure of the acoustic filter and presents the filter performance of the fabricated device in both, a narrow-band and a broadband range. Differences between synthesized and fabricated filters are modeled afterwards in order to account for all the out-of-band features. Measurements of the second harmonic have been performed over the bandwidth of the filter. Modeling of the nonlinear response has been developed by using nonlinear models of the acoustic wave resonators forming the filter., Peer Reviewed, Postprint (published version)

©2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., This paper describes a measurement setup to obtain the reflection coefficient response over the frequency of a given device when this is subjected to a single-tone high-power (HP) signal. The proposed system is based on a feed-forward technique to cancel the reflected HP signal before reaching the vector network analyzer. This allows measuring the effects of the HP interfering signal into the device's low-power frequency response. This technique does not require either power-calibrated standards or complex calibration techniques. Experiments in several devices are also reported to validate the suitability of this technique., Peer Reviewed, Postprint (author's final draft)

This master thesis is about the study of an Active Corner Reflector (ACR) to be used in C-band for Sentinel-1 satellite. The purpose is to design and implement a prototype to test to extract the first outcomes and suggestion for next improved version. Because of passive corner reflectors drawbacks (they are large, heavy, has an expensive installation, needs for maintenance because of weather or thermal conditions), this project proposes an active transceiver with a compact design and main requirements to guarantee a very low coupling transmitting and receiving antennas. The goal is to achieve a first prove of an active transponder which needs to be low cost, portable and reliable. In order to aims a low mutual impedance between transmitting and receiving antennas, the purpose is to design circularly polarized array antennas. The report content follows the study and the procedure to aim the active transponder with circularly polarized antennas. The introductory chapter offer a brief description of Sentinel-1 satellite. The next chapter defines the ACR requirements and scheme components with a first test in order to obtain indicative parameters. The project finally focuses on the design and realization of the circularly polarized patch array antenna.