Doctoral School

Reading date: 30/10/2026

• NI CHUIREAIN, FIONNUALA: Intrinsic Randomness in Quantum Information Theory
  
  Author: NI CHUIREAIN, FIONNUALA
  Programme: DOCTORAL DEGREE IN PHOTONICS
  Department: Institute of Photonic Sciences (ICFO)
  Mode: Normal
  Deposit date: 24/09/2026
  Reading date: 30/10/2026
  Reading time: 10:00
  Reading place: ICFO Auditorium
  Thesis director: ACÍN DAL MASCHIO, ANTONIO
  Thesis abstract: The unpredictability of quantum physics gives rise to an intrinsic form of randomness. We generate it by performing a measurement on a quantum state. In an adversarial scenario, we then quantify the randomness by the probability that a correlated eavesdropper could correctly guess the measurement outcomes. This thesis addresses the following question: given a known quantum state and measurement, how much intrinsic randomness can we generate?.We begin by solving the maximal intrinsic randomness of any state, optimised over all projective measurements, for four figures of merit: the conditional min, max and von Neumann entropies, and the newly introduced unambiguous randomness. The last of these describes an eavesdropper who is never wrong, but can sometimes return an inconclusive outcome. Relaxing the assumption of perfect accuracy, we also consider randomness given a fixed rate of inconclusive outcomes. We solve both of these quantities for any state and projective measurement in dimension two. If the setup is used to choose random bases for a prepare-and-measure quantum key distribution protocol, we show that the unambiguous randomness captures the knowledge gained by an eavesdropper about the secret key, without causing any disturbance. We then turn to extremal measurements beyond the projective case, which may have more outcomes. An unbiased measurement is one whose outcomes all have the same a priori probability. We characterise the randomness generated by any unbiased extremal rank-one measurement acting on any state, solving the problem explicitly in dimension two. Four-outcome measurements of this type are tomographic, such that one can fully determine the state from the outcome probabilities, so these results hold for fully source-device-dependent randomness too. The tetrahedral symmetric informationally complete (SIC) measurement, we find, has the least intrinsic randomness within this class. We also present the biased skewed SIC family of measurements, and use them to prove that 2 log d bits of randomness, the maximal amount, can be generated device-dependently (or source-device-independently) in any dimension d in which there exists a SIC measurement.Reversing the scenario, we optimise over all states to solve the maximal intrinsic randomness of two classes of non-extremal, or noisy, measurements: any two-outcome measurement in dimension two, and projective measurements in any dimension affected by isotropic noise. In a realistic implementation, however, neither the state nor the measurement is completely free of noise. Taking a simple example of a state measured in a basis of any dimension, we compare the case where only one device is affected by noise to that where both devices are noisy, such that an eavesdropper may have joint correlations with the state and the measurement. For a fixed amount of total noise, we find that, contrary to the common practice of attributing all experimental noise to a single device, the joint-noise eavesdropper strictly outperforms her single-noise counterpart, compromising the security of the randomness generated.That the outcomes of a quantum measurement are unpredictable has been known since the inception of quantum theory. This thesis presents a step forward in analytically characterising the intrinsic randomness of quantum physics. On the practical side, our results bound the functionality of quantum random number generators, under various assumptions. On a more foundational level, this work provides a new lens through which to compare quantum states and measurements and, from their vast landscape, to see which of them emerge as the most random.
  

Reading date: 02/11/2026

• MUÑOZ GALAN, HELENA: Sensor design and development for autonomous devices for disease diagnosis and therapy
  
  Author: MUÑOZ GALAN, HELENA
  Programme: DOCTORAL DEGREE IN POLYMERS AND BIOPOLYMERS
  Department: Department of Chemical Engineering (EQ)
  Mode: Normal
  Deposit date: 22/01/2026
  Reading date: pending
  Reading time: pending
  Reading place: pending
  Thesis director: ALEMAN LLANSO, CARLOS ENRIQUE | PÉREZ MADRIGAL, MARIA DEL MAR
  Thesis abstract: This doctoral research addresses key challenges in diabetes management by integrating sustainable materials, non-invasive sensing, and advanced insulin delivery technologies into a unified framework. Diabetes mellitus is a chronic metabolic disorder that requires continuous glucose monitoring and precise insulin administration to maintain glycemic control and reduce complications. Responding to these needs, the thesis is structured around three major contributions.First, the work advances the development of a previously created non-invasive glucose-monitoring device by incorporating recycled low-density polyethylene (LDPE) into the sensor design. The use of recycled LDPE improves sustainability, cost-efficiency, and environmental compatibility while maintaining reliable sensing performance. This demonstrates the feasibility of repurposing plastic waste in biomedical technologies without compromising functionality.Second, the research explores new strategies for controlled insulin delivery through stimuli-responsive hydrogels. Hydrogels based on poly(γ-glutamic acid) and multi-armed polyethylene glycol (PEG) were engineered to achieve sustained and tunable insulin release. The incorporation of poly(3,4-ethylenedioxythiophene) (PEDOT), a biocompatible conducting polymer, enables electrically triggered and on-demand insulin delivery. This approach offers a minimally invasive alternative to conventional injection-based therapies and highlights the potential of electro-responsive materials in smart drug-delivery systems.Finally, the thesis investigates the nanomechanical properties of multi-armed PEG hydrogels using a microcantilever-based optomechanical sensor. This analysis provides essential insights into the structural behavior, stability, and long-term performance of the hydrogels, contributing to the optimization of their mechanical robustness and responsiveness.Together, these contributions form a comprehensive strategy for improving diabetes care. By integrating non-invasive monitoring, environmentally conscious materials, and intelligent delivery platforms, the research promotes more sustainable biomedical solutions while advancing patient-centered therapeutic tools.
  

• NAVARRO GESSÉ, EDGAR: Synthesis, Design and COM-based Modeling of SAW Electroacoustic Filters
  
  Author: NAVARRO GESSÉ, EDGAR
  Programme: DOCTORAL DEGREE IN SIGNAL THEORY AND COMMUNICATIONS
  Department: Department of Signal Theory and Communications (TSC)
  Mode: Normal
  Deposit date: 01/10/2026
  Reading date: 02/11/2026
  Reading time: 11:00
  Reading place: Aula C4-028-2, Edifici C4 de l'Escola d'Enginyeria de Telecomunicació i Aeroespacial de Castelldefels (EETAC) de la UPC
  Thesis director: COLLADO GOMEZ, JUAN CARLOS | MATEU MATEU, JORDI
  Thesis abstract: Radio-frequency filtering is a key function in modern wireless systems, where demanding requirements on selectivity, bandwidth, compactness, and integration must be satisfied within a limited physical footprint. Surface acoustic wave (SAW) devices provide an attractive solution because they combine strong frequency selectivity with compact implementation. However, as filtering functions become more complex and conventional ladder architectures are complemented by multimode and hybrid configurations, the design problem extends beyond the synthesis of an equivalent electrical network: synthesized resonances, couplings, capacitances, and impedance levels must ultimately be translated into a physically realizable acoustic structure subject to the electroacoustic coupling, dispersive behaviour, geometrical constraints, and fabrication limitations of the selected technology.This thesis addresses the absence of a sufficiently systematic bridge between a prescribed filtering function and the final geometry of advanced SAW filters. The central approach is a synthesis–technology-adaptation–Coupling-of-Modes (COM) framework in which network synthesis establishes the required resonant and coupling conditions, topology-dependent circuit transformations or resynthesis enforce physical compatibility, and the resulting targets are mapped onto distributed COM structures that account for the physical dimensions of the interdigital acoustic geometry. The objective is not to replace physical modelling with an ideal equivalent circuit, but to preserve an explicit and repeatable correspondence between the prescribed response, a technology-compatible circuit representation, and the final acoustic geometry.At synthesis level, a unified driving-point extraction procedure combines finite-transmission-zero nonresonating-node sections with transmission-zero-at-infinity resonating-node sections, allowing a single filtering function to be partitioned between independent ladder resonators and multimode coupled-resonator-filter (CRF) sections. An enforced-zero deflation technique improves the numerical robustness of high-order synthesis by restoring the exact prescribed immittance root before each polynomial division. For conventional ladder filters, the Butterworth–Van Dyke-to-COM mapping is extended to a synthesis–mapping–resynthesis loop that accounts for the dispersive electroacoustic coupling of the technology.For multimode structures, a circuital Nakamura COM formulation and inverse-design procedures are developed for isolated two- and three-mode CRFs and extended to mixed ladder–CRF and cascaded-CRF architectures. The resulting design flow combines topology-specific circuit transformations with COM-based inverse design, incorporating the required impedance scalings, inverter transformations, static-capacitance compensation, technology-aware resynthesis, and physical partitioning needed to obtain realizable structures and ultimately determine their geometric dimensions. The proposed synthesis and circuit-transformation procedures are formulated and implemented as systematic and repeatable numerical procedures, while CRF inverse design and COM evaluation are implemented in a dedicated MATLAB design tool. The methodology is validated through COM simulations and measurements of fabricated ladder and two-mode CRF devices. A complementary tunable in-line filter further demonstrates the broader applicability of synthesis-based electroacoustic filter design, with measured continuous centre-frequency tuning from 0.99 to 1.03 GHz and up to 100% bandwidth control.Overall, the thesis establishes a systematic but topology-dependent methodology for translating prescribed filtering functions into physically realizable electroacoustic filter geometries, extending synthesis-driven design from conventional SAW ladders to multimode, mixed, cascaded, and reconfigurable architectures.
  

Reading date: 05/11/2026

• ALI, SALMAN: ANALYSIS OF THE INTEGRATION OF RENEWABLE ENERGY AND ENERGY STORAGE SYSTEMS IN SERIES-CASCADED MICROGRIDS
  
  Author: ALI, SALMAN
  Programme: DOCTORAL DEGREE IN ELECTRICAL ENGINEERING
  Department: Department of Electrical Engineering (DEE)
  Mode: Normal
  Deposit date: 29/09/2026
  Reading date: 05/11/2026
  Reading time: 10:00
  Reading place: ESEIAAT – TR5 – Expo Sala
  Thesis director: BOGARRA RODRIGUEZ, SANTIAGO | CORCOLES LOPEZ, FELIPE
  Thesis abstract: The increasing integration of renewable energy sources has transformed power distribution networks into decentralized energy systems. Distributed generation (DG) sources, including solar photovoltaic (PV), wind, fuel cells, hydropower, and other renewable resources, enable localized power generation and reduce dependence on centralized infrastructure. Microgrids (MGs) have emerged as a solution for integrating DG units. MG structures are widely adopted due to their control and protection characteristics. However, the low-voltage output of DG sources requires boost conversion stages, increasing system complexity and losses. Consequently, series-cascaded microgrids (SCMGs) have attracted attention.Despite their advantages, SCMGs face challenges in power sharing, voltage regulation, and integration of non-dispatchable DG (ND-DG) sources. Existing power routing controls generally assume ideal DC sources, limiting their applicability under renewable intermittency. Conventional approaches such as fundamental voltage reconstruction and third-harmonic voltage injection exhibit limited power sharing capability, constrained DC-link voltage margins, overmodulation risks, and degraded dynamic performance. To address these limitations, this thesis investigates an SCMG topology integrating ND-DG units and battery storage systems. A multi-power-carriers based control strategy incorporates third-harmonic current injection alongside fundamental component to enable inter-module power routing under reduced or zero ND-DG output. The proposed approach maintains desired multilevel output voltage while satisfying voltage and modulation constraints. In addition, proportional DC-side power utilization coordinates battery charging and discharging, supporting voltage stability and power sharing. Although the proposed methodology extends the power routing range, injected third-harmonic current appears in the grid current, affecting grid compatibility.To overcome this limitation, the SCMG architecture is extended to a delta-connected configuration. In this topology, third-harmonic current circulates within cascaded clusters, enabling inter-module power routing without propagating harmonics to the grid. Zero-sequence current injection is employed for inter-cluster power routing and symmetrical three-phase currents. The proposed framework determines optimal third-harmonic current, third-harmonic voltage, and zero-sequence injection, together with proportional DC-side power utilization control. Under adverse operating conditions, the fundamental component governs grid-compliant power exchange, the third-harmonic component enhances inter-module power redistribution, and the zero-sequence component ensures inter-cluster balancing.The proposed methodology is validated through MATLAB/Simulink simulations, hardware-in-the-loop experiments, and a laboratory-scale prototype. The results confirm stable multilevel voltage generation, effective DC-link stabilization, and robust inter-module and inter-cluster power routing. Overall, this thesis advances the state-of-the-art in SCMGs by introducing a scalable control framework that enables reliable operation under realistic microgrid conditions and supports renewable energy and energy storage integration in future smart power systems.
  

• HUSSAIN, TAUSEEF: Metamaterial-inspired Flexible Microwave Resonant Structures for RFID Sensing and Shielding
  
  Author: HUSSAIN, TAUSEEF
  Programme: DOCTORAL DEGREE IN ELECTRONIC ENGINEERING
  Department: Department of Electronic Engineering (EEL)
  Mode: Article-based thesis
  Deposit date: 20/07/2026
  Reading date: 05/11/2026
  Reading time: 15:30
  Reading place: Sala de Conferències TR1 – ESEIAAT, UPChttps://meet.google.com/fkh-mqus-zbt
  Thesis director: GIL GALI, IGNACIO | FERNANDEZ GARCIA, RAUL
  Thesis abstract: Metamaterials are artificially engineered electromagnetic structures that enable wave–matter interactions beyond those achievable with natural materials. When implemented in flexible and textile-compatible forms, metamaterial-inspired resonant structures offer unique advantages for wearable technologies, including conformability, lightweight construction, and tunable electromagnetic responses. These characteristics make them particularly attractive for wearable radio-frequency identification (RFID) sensing platforms, where sensitivity, robustness, and user safety must be addressed simultaneously. This thesis investigates the design and integration of metamaterial-inspired flexible resonant structures with RFID systems to enable sensors with enhanced performance and improved electromagnetic safety.Conventional RFID-based sensors typically rely on antenna deformation or substrate perturbation alone to transduce physical or biochemical stimuli. While effective in controlled environments, these approaches exhibit limited sensitivity and strong dependence on environmental loading in wearable scenarios. At ultra-high-frequency (UHF) bands, proximity to the human body causes impedance detuning and reduced read range reliability, whereas at microwave frequencies, increased absorption in biological tissue raises specific absorption rate (SAR) concerns. These limitations motivate the use of engineered resonant structures that offer enhanced field confinement and improved control over antenna–environment interactions.This thesis first investigates resonator-assisted passive UHF RFID sensing for biomechanical and biochemical monitoring. Electromagnetic coupling between printed UHF RFID tag antennas and compact resonant elements is exploited to enhance sensitivity beyond conventional antenna-based sensing. Meander-line resonators are integrated with RFID tags to enable displacement sensing, demonstrating reliable respiration and knee-flexion monitoring. The coupling approach is further extended to biochemical sensing through the integration of a capacitively coupled complementary split-ring resonator (CSRR) with an H-slot RFID antenna, enabling passive wireless monitoring of glucose concentration via read-range modulation.Subsequently, the thesis addresses electromagnetic stability and user safety at microwave RFID frequencies, where shorter wavelengths enable compact resonator arrays to be realized as metasurfaces. A breathable ground-grid artificial magnetic conductor (GG-AMC) is developed to mitigate body-induced detuning, suppress backward radiation, and significantly reduce SAR while preserving wearer comfort. In addition, near-field coupled metamaterial absorbers are introduced as dual-function structures that simultaneously provide electromagnetic shielding and strain-sensitive resonance modulation, enabling respiration monitoring at microwave frequencies. The core scientific contributions of this research are documented in five JCR-indexed journal articles and two peer-reviewed IEEE conference publications, and the thesis is presented as a compendium of articles.Keywords – RFID sensing, wearable sensors, microwave resonators, metasurfaces, biomechanical monitoring, biochemical sensing, artificial magnetic conductor, metamaterial absorber, electromagnetic shielding.