/library/oar/handle/123456789/2070 2025-12-21T21:37:22Z /library/oar/handle/123456789/142199 Title: Experimental investigation of thermal tuning for laterally excited bulk acoustic wave MEMS resonators using SOI bulk heating Authors: Bengashier, Munira; Casha, Owen; Grech, Ivan; Farrugia, Russell; Micallef, Joseph; Gatt, Edward Abstract: This paper presents the experimental investigation of electrothermal fine frequency tuning for a 60 MHz laterally excited contour mode bulk acoustic wave MEMS resonator, fabricated using the PiezoMUMPs multiprocess wafer process. Tuning is achieved via electrothermal SOI bulk heating of the resonator, so that its resonant frequency is shifted by inducing additional stresses in the device, as well as varying its elastic properties via a temperature change. Experimental results show that the resonant frequency decreases with an increase in the electrical heating power, which is applied to the resonator SOI bulk via two heating electrodes. For a 50-mW heating power swing, the resonator frequency varies from 61.368 MHz to 61.418 MHz. Measured results show that the SOI bulk resistance remains approximately constant over this tuning range, with a value of around 31 Ω . The discussion of the experimental results is aided and confirmed via finite element modelling and simulation. 2024-10-01T00:00:00Z /library/oar/handle/123456789/142102 Title: An analytical approach for designing passive matching networks Authors: Casha, Owen Abstract: This paper presents an analytical approach for designing three-component T-section or π-section passive matching networks by using a direct and generic impedance or admittance network analysis. This approach is proposed as an alternative technique for designing such networks, which can be achieved through either a graphical approach using an impedance-admittance Smith chart, a back-to-back L-section-based matching network design, or a phase-shift-based approach. The proposed approach provides all possible T-section or π-section passive matching network configurations and their respective component values with high accuracy by analytically solving three equations, as demonstrated by the implemented algorithm. 2025-11-01T00:00:00Z /library/oar/handle/123456789/140785 Title: Demonstration of full polarization control of soft X-ray pulses with Apple X undulators at SwissFEL using recoil ion momentum spectroscopy Authors: Kittel, Christoph; Sarracini, Antoine; Augustin, Sven; Yang, Ningchen; Al Haddad, Andre; Ferrari, Eugenio; Knopp, Gregor; Knurr, Jonas; Morillo-Candas, Ana Sofia; Swiderska, Iwona; Prat, Eduard; Sammut, Nicholas; Schmidt, Thomas; Bostedt, Christoph; Calvi, Marco; Schnorr, Kirsten Abstract: The ability to freely control the polarization of X-rays enables measurement techniques relying on circular or linear dichroism, which have become indispensable tools for characterizing the properties of chiral molecules or magnetic structures. Therefore, the demand for polarization control in X-ray free-electron lasers is increasing to enable polarization-sensitive dynamical studies on ultrafast time scales. The soft X-ray branch Athos of SwissFEL was designed with the aim of providing freely adjustable and arbitrary polarization by building its undulator solely from modules of the novel Apple X type. In this paper, the magnetic model of the linear inclined and circular Apple X polarization schemes are studied. The polarization is characterized by measuring the angular electron emission distributions of helium for various polarizations using cold target recoil ion momentum spectroscopy. The generation of fully linear polarized light of arbitrary angle, as well as elliptical polarizations of varying degree, are demonstrated. 2024-01-01T00:00:00Z /library/oar/handle/123456789/138445 Title: Advancing prosthesis design : ontology driven multi-disciplinary framework for evolving amputee needs Authors: Patiniott, Nicholas; Borg, Jonathan C.; Farrugia, Philip; Casha, Owen; Gatt, Alfred; Mercieca, Adrian Abstract: To address the evolving life-cycle needs of both the amputee and prosthesis, input from key stakeholder (amputees and family members, prosthetist, physiotherapist, and prosthesis technician) is essential. Collaborative decision-making is necessary for timely involvement in the design, redesign, and maintenance of prostheses. Our framework, adProLiSS, supports this process by integrating stakeholder knowledge and real-time data obtained from smart prosthetic devices. Through an Ontology-Driven Prosthesis-Service System Framework incorporating an Ontology-Driven Consequence Mapping Model, key decision makers can visualise the consequences of their choices, enhancing communication, alignment, and adaptability. This holistic, data-driven approach prioritises patient-centred care, advocating for a paradigm shift in healthcare design practices. 2025-01-01T00:00:00Z