Synthesis procedure for ladder acoustic wave filters starting in series resonator

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 ReviewedPostprint (author's final draft

Acoustic wave transversal filter for 5G N77 band

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

Nonlinear effects of SiO2 layers in bulk acoustic wave resonators

©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.This paper presents the development of a comprehensive distributed circuit model to account for the existing nonlinear effects in bulk acoustic wave (BAW) resonators. The comprehensiveness of the model and its distributed implementation allow for the inclusion of the nonlinear effects occurring in any layer of the BAW configuration, not only the piezoelectric layer. The model has been applied to evaluate the nonlinear contribution of the piezoelectric layer and silicon dioxide (SiO₂) layer in the Bragg reflector. The nonlinear manifestations are a function of the frequency of the driving fundamental tones. Accurate measurements of state-of-the-art resonators validate the model proposed and confirm the contribution of the SiO₂ layer in the overall nonlinear performance.Peer ReviewedPostprint (author's final draft

Comprehensive circuit model of autolimiting superconductor devices

©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.This paper presents a phenomenological equivalent circuit to model the phenomenon occurring when a section of superconducting transmission line transits from a superconducting state to a normal state. This phenomenon allows the use of superconductors for the design of autolimiting structures based on superconducting transmission line sections. Although this autolimiting effect happens when the current density achieved in the superconductor exceeds the critical current inherent to the superconducting material, heating effects also play a significant role in this behavior. The equivalent circuit presented in this work accounts for both electric and thermal effects, and the interaction between them. The circuit model is then used for the evaluation of a practical microwave and frequency selective IMUX configuration.Peer ReviewedPostprint (author's final draft

N-Plexer and N-Band acoustic filters based on transversal configuration

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 ReviewedPostprint (published version

Wideband transversal acoustic wave filters. Application to connected cars

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 ReviewedPostprint (published version

Nonlinear performance on acoustic transversal filters

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 813Peer ReviewedPostprint (published version